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BACKGROUND OF THE INVENTION
The subject matter disclosed herein relates to detecting impact forces on aircraft, and in particular to detecting landing gear impact on aircraft.
Aircraft such as, for example, rotary wing aircraft and fixed wing aircraft use a variety of sensors to provide feedback to aircraft control systems. Detecting when a force, such as weight, is applied to the landing assemblies or other portions of an aircraft provides useful feedback to aircraft systems. Previous systems used sensors located on each landing assembly to determine whether weight was applied to a landing assembly. The use of these sensors increased the weight and complexity of the aircraft, and had limited fidelity in sensing actual weight applied to a landing assembly.
BRIEF DESCRIPTION OF THE INVENTION
According to one aspect of the invention, a method for sensing a force applied to an aircraft includes defining a first velocity vector as a function of a first velocity due to a rotation motion of the aircraft, defining a second velocity vector as a function of a second velocity due to the rotation motion of the aircraft, defining an instant axis of rotation of the aircraft as a function of the first velocity vector and the second velocity vector, determining whether a force has been exerted on a first portion of the aircraft, and outputting an indication that a force has been exerted on the first portion of the aircraft responsive to determining that the force has been exerted on the first portion of the aircraft.
According to another aspect of the invention, a system for sensing a force applied to an aircraft includes a first sensor, a second sensor, and a processor operative to define a first velocity vector as a function of a first velocity due to a rotation motion of the aircraft, define a second velocity vector as a function of a second velocity due to the rotation motion of the aircraft, define an instant axis of rotation of the aircraft as a function of the first velocity vector and the second velocity vector, determine whether a force has been exerted on a first portion of the aircraft, and output an indication that a force has been exerted on the first portion of the aircraft responsive to determining that the force has been exerted on the first portion of the aircraft.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWING
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 illustrates a block diagram of an exemplary embodiment of an aircraft 100 .
FIG. 2 illustrates an example of the geometric relationship between sensors and a nose landing assembly of FIG. 1 .
FIG. 3 illustrates a block diagram of an exemplary embodiment of logic performed by the processor of FIG. 1 .
FIG. 4 illustrates an exemplary diagram of a Euler Axis estimation.
FIG. 5 illustrates an exemplary diagram of a Euler Axis and a landing assembly.
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a block diagram of an exemplary embodiment of an aircraft 100 . The aircraft 100 includes a nose landing assembly 101 , a left landing assembly 103 , and a right landing assembly 105 . The landing assemblies may include, for example, a landing gear assembly that includes an inflatable wheel, or any other device that is operative to contact a landing surface. For example a skid assembly may be used, and portions of the skid assembly may be designated as contact points similar to the gear described above. The aircraft 100 includes a processor 102 that is communicatively connected to flight controls 104 and sensors 106 that may include, for example, a gyro sensor, one or more accelerometers, two or more velocity sensors from, for example, a global positioning system (GPS), or any other inertial sensors. The processor 102 may also be communicatively connected to a memory 110 and a display 108 .
FIG. 2 illustrates an example of the geometric relationship between a sensor 106 , sensor 107 and the nose landing assembly 101 including an example of coordinate systems that are associated with the sensor 106 , the sensor 107 and the nose landing assembly 101 .
FIG. 3 illustrates a block diagram of an exemplary embodiment of logic performed by the processor 102 (of FIG. 1 ). In this regard, the processor 102 receives input data from the sensors (sensors_i; where i=1, 2, 3, . . . ) 106 . The input includes acceleration (a i x , a i y , and a i z ) from, for example, an accelerometer, velocity (v i x , v i y , v i z ) from, for example, a GPS or derived from an accelerometer, and a rate of change in orientation (P, Q, R) from, for example, a gyro. In block 302 , the processor 102 performs an initialization routine that receives minimum rotation parameters (α, β, γ) 301 where α is the minimum angular velocity norm threshold value, β is the minimum angular velocity derivative norm threshold value and γ is the minimum acceleration norm threshold value, and determines whether a minimum rotation norm (MRN) condition has been satisfied as follows:
MRN:={(|{right arrow over (ω)}|>α)&({dot over ({right arrow over (ω)}|>β} (1)
The processor 102 resets the aircraft velocities and accelerations values as follows:
At
:
t
=
t
1
where
{
MRN
is
true
}
,
then
:
{
v
→
trans
i
=
v
→
i
(
t
1
)
&
a
→
trans
i
=
a
→
i
(
t
1
)
(
2
)
Thereafter the initialization routine outputs velocities and accelerations due to the rotation motion of the aircraft only ({right arrow over (v)} rot i and {right arrow over (v)} rot i ) where:
For
:
t
>
t
1
where
{
MRN
is
true
}
,
then
:
{
v
→
rot
i
=
v
→
i
-
v
→
trans
i
&
a
→
rot
i
=
a
→
i
-
a
→
trans
i
(
3
)
The initialization routine determines whether the acceleration norm due to the rotation motion of the aircraft exceed the acceleration norm threshold value (γ) to output an enabling signal (Enable) to enable the landing detection process, as follows:
if {(MRN is true)&({right arrow over (α)} rot i |>γ)}, then: Enable=1 (4)
In block 304 the processor 102 receives sensor coordinates (P i sensor ) 303 , which includes locations of the sensors, and performs Euler-Axis routine that determines an instant axis of rotation of the aircraft defined as the intersection line of two non-parallel planes as illustrated in FIG. 4 . Geometrically, the intersection line, axis of rotation, is defined by a unit directional vector {right arrow over (u)} axis and a specific point defined P axis on the axis. The parametric equation of the axis of rotation is given by:
P axis ( s )= P axis +{right arrow over (u)} axis ·s (5)
In a three dimensional space, plane Δ is defined by a point P and a normal vector {right arrow over (n)}. Two planes Δ 1 and Δ 2 are not parallel if their normal vectors {right arrow over (n)} 1 and {right arrow over (n)} 2 are not parallel; this is equivalent to the cross product norm condition (CPN), where CPN=|{right arrow over (n)} 1 ×{right arrow over (n)} 2 |≧μ>>0. To determine the axis of rotation directional unit vector {right arrow over (u)} axis ; the best two non parallel velocity vectors are selected by maximizing CPN, where:
CPN=max{| {right arrow over (v)} rot 1 ×{right arrow over (v)} rot 2 |,{right arrow over (v)} rot 1 ×{right arrow over (v)} rot 3 |,|{right arrow over (v)} rot 2 ×{right arrow over (v)} rot 3 |} (6)
In vector space, the axis of rotation directional unit vector is given by:
u
→
axis
=
{
v
→
rot
1
×
v
→
rot
2
v
→
rot
1
×
v
→
rot
2
,
if
CPN
=
v
→
rot
1
×
v
→
rot
2
v
→
rot
1
×
v
→
rot
3
v
→
rot
1
×
v
→
rot
2
,
if
CPN
=
v
→
rot
1
×
v
→
rot
3
v
→
rot
2
×
v
→
rot
3
v
→
rot
2
×
v
→
rot
3
,
if
CPN
=
v
→
rot
2
×
v
→
rot
3
(
7
)
To simplify the example, CPN==|{right arrow over (v)} rot 1 ×{right arrow over (v)} rot 2 |, thus selecting sensor_ 1 and sensor_ 2 for the detection process.
To determine the intersection line, axis of rotation, a specific point is found on the line, that is, to find a point P axis that lies in both planes Δ 1 and Δ 2 , thereby solving implicit equations of Δ 1 and Δ 2 for P axis :
Δ 1 :{right arrow over (v)} rot 1 ·( P axis −P sensor 1 )=0
Δ 2 :{right arrow over (v)} rot 2 ·( P axis −P sensor 2 )=0 (8)
Equivalently solving for three coordinates P axis — x , P axis — y , and P axis — z :
{
v
rot
_
x
1
P
axis
_
x
1
+
v
rot
_
y
1
P
axis
_
y
1
+
v
rot
_
z
1
P
axis
_
z
1
=
d
1
v
rot
_
x
2
P
axis
_
x
2
+
v
rot
_
y
2
P
axis
_
y
2
+
v
rot
_
z
2
P
axis
_
z
2
=
d
2
(
9
)
Where d 1 and d 2 are known constants given by:
{
d
1
=
v
rot
_
x
1
P
sensor
_
x
1
+
v
rot
_
y
1
P
sensor
_
y
1
+
v
rot
_
z
1
P
sensor
_
z
1
d
2
=
v
rot
_
x
2
P
sensor
_
x
2
+
v
rot
_
y
2
P
sensor
_
y
2
+
v
rot
_
z
2
P
sensor
_
z
2
(
10
)
For a robust solution of Equation 9, a direct linear equation algorithm is used. First a largest absolute coordinate value, noted δ, of {right arrow over (u)} axis given by equation 7, is selected by:
δ=max{absolute( u axis — x ,u axis — y ,u axis — z )} (11)
Depending of the value of 6 from equation 11, the corresponding coordinate of P axis is set to zero. Solving for the two other coordinates, the equation 9 gives the general solution for P axis expressed as:
P
axis
=
{
(
0
,
d
2
·
v
rot
_
z
1
-
d
1
·
v
rot
_
z
2
,
d
1
·
v
rot
_
y
2
-
d
2
·
v
rot
_
y
1
)
v
rot
_
y
1
·
v
rot
_
z
2
-
v
rot
_
z
1
·
v
rot
_
y
2
;
if
δ
=
abs
(
u
axis
_
x
)
(
d
2
·
v
rot
_
z
1
-
d
1
·
v
rot
_
z
2
,
0
,
d
1
·
v
rot
_
x
2
-
d
2
·
v
rot
_
x
1
)
v
rot
_
x
1
·
v
rot
_
z
2
-
v
rot
_
z
1
·
v
rot
_
x
2
;
if
δ
=
abs
(
u
axis
_
y
)
(
d
2
·
v
rot
_
y
1
-
d
2
·
v
rot
_
y
2
,
d
1
·
v
rot
_
x
2
-
d
2
·
v
rot
_
x
1
,
0
)
v
rot
_
x
1
·
v
rot
_
y
2
-
v
rot
_
y
1
·
v
rot
_
x
2
;
if
δ
=
abs
(
u
axis
_
z
)
(
12
)
In block 306 , the axis-distances routine receives gear coordinates 305 that include locations of the gears P k gear 101 , 103 , 105 (of FIG. 1 ), and using equations 13 and 14, computes and outputs λ k axis-gear and λ cg parameters defined as the distances from the estimated instant axis of rotation to the extended landing gears end points and the aircraft center of gravity as illustrated in FIG. 5 .
λ axis-gear k =|( P gear k −P axis )× {right arrow over (u)} axis |; K= 1,2,3 (13)
λ cg =|P axis ×{right arrow over (u)} axis | (14)
In block 308 , the detection logic determines if the distance from the axis of rotation to a given gear is the minimum of the axis-distances values and is less than a gear-axis-distance threshold value defined as a gear-cylinder-diameter λ cylinder 307 and the distance from the axis of rotation to center of gravity of the aircraft exceeds the gear-axis-distance threshold value then the detection logic identifies the landing gear as center-of-rotation. The detection logic outputs a weight on wheel (force on wheel) signal 310 indicating contact:
WoW = K if { min k ( λ axis - gear k ) < λ cylinder & λ cg > λ cylinder ( 15 )
With: WOW=1→left gear; WOW=2→right gear; WOW=3→foward gear.
The gear WoW signal 310 in FIG. 3 indicates that a weight on wheel has occurred on the gear. The indication provides information to the aircraft 100 operator and/or automatic control systems of the aircraft 100 that assists in operating the aircraft. Particularly, the weight on wheel signal may indicate that the aircraft has landed or has taken off from a landing area.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
|
A system for sensing a force applied to an aircraft includes a first sensor, a second sensor, and a processor operative to define a first velocity vector as a function of a first velocity due to a rotation motion of the aircraft, define a second velocity vector as a function of a second velocity due to the rotation motion of the aircraft, define an instant axis of rotation of the aircraft as a function of the first velocity vector and the second velocity vector, determine whether a force has been exerted on a first portion of the aircraft, and output an indication that a force has been exerted on the first portion of the aircraft responsive to determining that the force has been exerted on the first portion of the aircraft.
| 1
|
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit of Great Britain patent application number 1121272.7, filed on Dec. 12, 2011, which is hereby incorporated by reference to the maximum extent allowable by law.
BACKGROUND
[0002] 1. Technical Field
[0003] The present application relates to processor communications and in particular but not exclusively for processor communication for controlling shared memory data flow. One embodiment is for controlling multiprocessor data transfers accessing a shared memory on a single integrated circuit package, but can be used in any shared memory controller.
[0004] 2. Discussion of the Related Art
[0005] Microprocessor-based systems are increasingly containing multiple central processor units (CPU) or cores which are required to communicate with each other. A method for implementing this communication between CPU cores is to use an area of shared memory. However using shared memory requires the control of the flow of data through the shared memory area. For example the shared memory area is required to be controlled such that the receiving processor does not attempt to read data before the sender has placed it in the memory, a read after write (RAW) hazard, where the receiving processor accesses the old data. Furthermore the shared memory should be controlled such that the sending processor does not attempt to overwrite data in the shared memory before the receiver has read the data on the memory, a write after read (WAR) hazard where the receiver cannot access the old data.
[0006] These hazards have been researched and proposed solutions have involved implementing flow control in shared memory as a circular buffer where the sender send a write pointer (WP), indicating the next memory location to be sent data by the sender, to the receiver and the receiver sends a read pointer (RP), indicating the next memory location to the read from by receiver, to the sender.
[0007] In such examples the sender places data in the buffer, updates its local write pointer, and sends the new pointer value to the receiver.
[0008] The receiver receives the updated write pointer, compares it to its read pointer and the comparison enables the receiver to determine whether it can read data from the current read pointer address (in other words the receiver when detecting the difference between the read pointer and write pointer is greater than a threshold enables a read operation to occur).
[0009] The receiver when a read operation on the shared memory is performed can then send an updated read pointer back to the sender.
[0010] The sender, on receiving the updated read pointer, has the information that the receiver has read the data from the buffer, and thus can ‘clear’ the memory space, enabling the sender to write data again providing the sender write operation does not result in the write pointer catching up with or passing the read pointer.
[0011] However such communication of pointers between the processors may require pointers which are large enough to address the whole of the buffer. For example a buffer with 256 locations requires a minimum of eight bits per pointer. Furthermore the flow control can implement pointers as relative addresses (relative to the base of the buffer), or absolute addresses. Thus the read and write pointers can require typically 32 bit addressing capability (or even larger numbers of bits per pointer).
[0012] Furthermore such communication is problematic where the sender and receiver are on separate chips (or on the same chip) separated by significant routing distance. In such examples the overhead of communicating multiple wires between the sender and receiver could be unacceptably high.
[0013] Although there has been suggestion that further shared memory locations can be used to store the read and write pointer values, and thus not require the transfer of write and read pointers between the central processing units, the use of additional shared memory space places different communication loads on both the sender and receiver to poll the pointer locations for updated pointer values.
[0014] Furthermore where the sender and receiver are in separate clock domains the communication of read and write pointers require additional hardware to ensure the pointers are communicated safely without corruption due to clock domain boundary errors.
[0015] Further flow control designs determine a common transfer size between sender and receiver, enable the sender to maintain local read and write pointers, and enable the receiver to maintain a local read pointer. Such examples further are configured to allow the sender to contain a memory mapped register which drives a request signal to the receiver. Furthermore in such examples allow the receiver to contain a further memory mapped register which drives and an acknowledgement signal to the sender. In such examples the sender can place data into the buffer, update the sender write pointer, then compare the read and write pointers so that where the sender determines that the amount of data in the buffer is more than the agreed transfer size the sender sets a request signal by writing to the memory mapped register.
[0016] The receiver sees the request signal asserted and reads the agreed amount of data from the shared memory buffer. Once the receiver has read the data the receiver uses the receiver memory mapped register to invert the acknowledged signal. The sender then detects the edge of the acknowledged signal and updates the sender read pointer to take account of the data read from the shared memory buffer. Then based on the current fill level of the shared memory buffer the sender can choose to clear or assert the request signal.
[0017] These examples of flow control allow flow control to be maintained because the receiver will not attempt to read data from the buffer unless the request is asserted. Also the sender will not write data into the buffer if the write pointer passes the read pointer as the sequence of edges on the acknowledge signal ensure that the sender's copy of the read pointer is kept up to date.
[0018] In such examples only two wires between the sender and receiver, a request write wire and an acknowledge wire are required. However the request and acknowledge signals require very fast propagation between the sender and receiver. Where propagation is slow then the receiver can poll the request signal before the previous acknowledgement edge has propagated through to the de-assertion of the request resulting in a single request being serviced twice by the sender. This can for example generate memory buffer underflow.
SUMMARY
[0019] At least one embodiment provides a shared memory communication system between two separately clocked processors throughout the shared memory area to be used as a circular buffer while minimizing the number of connecting signals and being tolerant of high propagation latency on these signals.
[0020] According to one aspect there is provided a processor module comprising: a processor configured to share data with at least one further processor module processor; and a memory mapped peripheral configured to communicate with at least one further processor memory mapped peripheral to control the sharing of the data, wherein the memory mapped peripheral comprises a sender part comprising: a data request generator configured to output a data request indicator to the further processor module dependent on a data request register write signal from the processor; and an acknowledgement waiting signal generator configured to output an acknowledgement waiting signal to the processor dependent on a data acknowledgement signal from the further processor module, wherein the data request generator data request indicator is further dependent on the data acknowledgement signal and the acknowledgement waiting signal generator acknowledgement waiting signal is further dependent on the acknowledgement waiting register write signal.
[0021] The data request generator may comprise a first flip-flop configured to receive as a set input the data request register write signal, as a dominant clear input the acknowledgement waiting signal and to output a first provisional data request signal.
[0022] The data request generator may further comprise an AND logic combiner configured to receive as a first input the first provisional data request signal, as a second input an inverted acknowledgement waiting signal and to output a second provisional data request signal.
[0023] The data request generator may further comprise an XOR logic combiner configured to receive as a first input the second provisional data request signal and as a second input dependent on the data acknowledgement signal and to output a third provisional data request signal.
[0024] The data request generator may further comprise a second flip flop configured to output a synchronized third provisional data request signal as the data request indicator.
[0025] The acknowledgement waiting signal generator may comprise a first flip-flop configured to receive as a dominant set input an edge detected acknowledgement signal, as a clear input the acknowledgement waiting register write signal from the processor and to output the acknowledgement waiting signal to the processor.
[0026] The acknowledgement waiting signal generator may further comprise an edge detector configured to detect an edge change of the data acknowledgement signal from the further processor module.
[0027] The acknowledgement waiting signal generator may further comprise a data acknowledgement synchronizer configured to synchronize the data acknowledgement signal from the further processor module into a clock domain of the processor module.
[0028] The processor may be configured to share data with the at least one further processor module processor via a memory.
[0029] According to another aspect there is provided a processor module comprising: a processor configured to share data with at least one further processor module processor; and a memory mapped peripheral configured to communicate with at least one further processor memory mapped peripheral to control the sharing of the data, wherein the memory mapped peripheral comprises a receiver part comprising: a data acknowledgement generator configured to output a data acknowledgement signal to the further processor module dependent on a data acknowledgement register write signal from the processor; and a data request waiting signal generator configured to output a data request waiting signal to the processor dependent on a data request signal from the further processor module, and the data acknowledgement signal.
[0030] The data acknowledgement generator may comprise a toggle flip flop configured to receive as a input the data acknowledgement register write signal from the processor and to output the data acknowledgement signal to the further processor module.
[0031] The data request waiting signal generator may comprise an XOR logic combiner configured to receive as a first input the toggle flip-flop output, as a second input the data request signal from the further processor module and to output the data request waiting signal to the processor.
[0032] The data request waiting signal generator may further comprise a data request synchronizer configured to synchronize the data request signal from the further processor module into a clock domain of the processor module.
[0033] The processor may be configured to share data with the at least one farther processor module processor via a memory.
[0034] According to another aspect there is provided a processor module comprising: means for sharing data with at least one further processor module processor; and means for communicating with at least one further processor to control the sharing of the data, wherein the means for communicating with at least one further processor memory mapped processor comprises means for controlling sending data to the processor module comprising: means for outputting a data request indicator to the further processor module dependent on a data request register write signal from the processor; and means for outputting an acknowledgement waiting signal to the processor dependent on a data acknowledgement signal from the further processor module, wherein the means for outputting a data request indicator is further dependent on the data acknowledgement signal and the means for outputting an acknowledgement waiting signal is further dependent on the data acknowledgement waiting register write signal.
[0035] The means for outputting a data request indicator may comprise a first flip-flop configured to receive as a set input the data request register write signal, as a dominant clear input the acknowledgement waiting signal and to output a first provisional data request signal.
[0036] The means for outputting a data request indicator may further comprise an AND logic combiner configured to receive as a first input the first provisional data request signal, as a second input an inverted acknowledgement waiting signal and to output a second provisional data request signal.
[0037] The means for outputting a data request indicator may further comprise an XOR logic combiner configured to receive as a first input the second provisional data request signal and as a second input dependent on the data acknowledgement signal and to output a third provisional data request signal.
[0038] The means for outputting a data request indicator may further comprise a second flip flop configured to output a synchronized third provisional data request signal as the data request indicator.
[0039] The means for outputting an acknowledgement waiting signal may comprise a first flip-flop configured to receive as a dominant set input an edge detected acknowledgement signal, as a clear input the data acknowledgement waiting register write signal from the processor and to output the acknowledgement waiting signal to the processor.
[0040] The means for outputting an acknowledgement waiting signal may further comprise an edge detector configured to detect an edge change of the data acknowledgement signal from the further processor module.
[0041] The means for outputting an acknowledgement waiting signal may further comprise means for synchronizing the data acknowledgement signal from the further processor module into a clock domain of the processor module.
[0042] The processor may be configured to share data with the at least one further processor module processor via a memory.
[0043] According to another aspect there is provided a processor module comprising: means for sharing data with at least one further processor module processor; and means for communicating with at least one further processor to control the sharing of the data, wherein the means for communicating with at least one further processor memory mapped processor comprises means for controlling receiving data comprising: means for outputting a data acknowledgement signal to the further processor module dependent on a data acknowledgement register write signal from the processor; and means for outputting a data request waiting signal to the processor dependent on a data request signal from the further processor module and the data acknowledgement signal.
[0044] The means for outputting a data acknowledgement signal may comprise a toggle flip flop configured to receive as an input the data acknowledgement register write signal from the processor and to output the data acknowledgement signal to the further processor module.
[0045] The means for outputting a data request waiting signal may comprise an XOR logic combiner configured to receive as a first input the toggle flip-flop output, as a second input the data request signal from the further processor module and to output the data request waiting signal to the processor.
[0046] The means for outputting a data request waiting signal may further comprise means for synchronizing the data request signal from the further processor module into a clock domain of the processor module.
[0047] The processor may be configured to share data with the at least one further processor module processor via a memory.
[0048] According to another aspect there is provided a method comprising: sharing data between a processor module and at least one further processor module processor; and communicating with at least one further processor to control the sharing of the data, wherein communicating with at least one further processor comprising controlling sending data to the processor comprising: outputting a data request indicator to the further processor module dependent on a data request register write signal from the processor; and outputting an acknowledgement waiting signal to the processor dependent on a data acknowledgement signal from the further processor module, wherein outputting a data request indicator is further dependent on the data acknowledgement signal and outputting an acknowledgement waiting signal is further dependent on the acknowledgement waiting register write signal.
[0049] Outputting a data request indicator may comprise configuring a first flip-flop to receive as a set input the data request register write signal, as a dominant clear input the acknowledgement waiting signal and to output a first provisional data request signal.
[0050] Outputting a data request indicator may further comprise configuring an AND logic combiner to receive as a first input the first provisional data request signal, as a second input an inverted acknowledgement waiting signal and to output a second provisional data request signal.
[0051] Outputting a data request indicator may further comprise configuring an XOR logic combiner to receive as a first input the second provisional data request signal and as a second input dependent on the data acknowledgement signal and to output a third provisional data request signal.
[0052] Outputting a data request indicator may further comprise configuring a second flip flop to output a synchronized third provisional data request signal as the data request indicator.
[0053] Outputting an acknowledgement waiting signal may comprise configuring a flip-flop to receive as a dominant set input an edge detected acknowledgement signal, as a clear input the data acknowledgement waiting register write signal from the processor and to output the ack
[0054] Outputting an acknowledgement waiting signal may further comprise configuring an edge detector configured to detect an edge change of the data acknowledgement signal from the further processor module.
[0055] Outputting an acknowledgement waiting signal may further comprise synchronizing the data acknowledgement signal from the further processor module into a clock domain of the processor module.
[0056] Sharing data between a processor module and at least one further processor module processor may comprise sharing data sharing data via a memory.
[0057] According to another aspect there is provided a method comprising: sharing data between a processor module and at least one further processor module processor; and communicating with at least one further processor to control the sharing of the data, wherein communicating with at least one further processor memory mapped processor comprises controlling receiving data comprising: outputting a data acknowledgement signal to the further processor module dependent on a data acknowledgement register write signal from the processor; and outputting a data request waiting signal to the processor dependent on a data request signal from the further processor module and the data acknowledgement signal.
[0058] Outputting a data acknowledgement signal may comprise configuring a toggle flip flop to receive as an input the data acknowledgement register write signal from the processor and to output the data acknowledgement signal to the further processor module.
[0059] Outputting a data request waiting signal may comprise configuring an XOR logic combiner to receive as a first input the toggle flip-flop output, as a second input the data request signal from the further processor module and to output the data request waiting signal to the processor.
[0060] Outputting a data request waiting signal may further comprise synchronizing the data request signal from the further processor module into a clock domain of the processor module.
[0061] Sharing data between a processor module and at least one further processor module processor may comprise sharing data sharing data via a memory.
[0062] A processor-readable medium may be encoded with instructions that, when executed by a processor, perform a method as described herein.
[0063] Apparatus comprising at least one processor and at least one memory including computer code for one or more programs, the at least one memory and the computer code configured to with the at least one processor may cause the apparatus to at least perform a method as described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] For better understanding of the present application, reference will now be made by way of example to the accompanying drawings in which:
[0065] FIG. 1 shows schematically a shared memory system suitable for employing some embodiments of the application;
[0066] FIG. 2 shows schematically a sender MMP in further detail according to some embodiments of the application;
[0067] FIG. 3 shows schematically a receiver MMP in further detail according to some embodiments of the application;
[0068] FIG. 4 shows a flow diagram of the shared memory controller with respect to the sender request operations according to some embodiments of the application;
[0069] FIG. 5 shows a flow diagram of the shared memory controller with respect to the receiver request and acknowledgement operations according to some embodiments of the application; and
[0070] FIG. 6 shows a flow diagram of the shared memory controller with respect to the sender acknowledgement operations according to some embodiments of the application.
DETAILED DESCRIPTION
[0071] The following describes in further detail suitable apparatus and possible mechanisms for the provision of shared memory controlling.
[0072] With respect to FIG. 1 an example system, device or apparatus is shown within which embodiments can be implemented. The system is shown comprising a first device 10 (Device 1 ), the sender, which is configured in the following examples as the device sending the data to the memory. The system is further shown comprising a second device 20 (Device 2 ), the receiver, which is configured in the following examples as the device receiving or reading data from the shared memory. The system is shown further comprising a shared memory 30 comprising a shared ring buffer portion 31 configured to be accessible for both the first device and the second device.
[0073] It would be understood that the first device 10 and the second device 20 can be any suitable electronic processing unit, such as processing cores fabricated on the same or different silicon structures, or packaged with the same or different integrated circuit packages. In some embodiments the first device 10 , the second device 20 and the shared memory 30 are fabricated on the same silicon structure or packaged within the same integrated circuit package. In some embodiments the first device 20 is synchronized by a first clock domain signal and the second device 20 is synchronized by a second clock domain signal. In some embodiments the first clock domain signal and the second clock domain signal are the same signal, however the following examples are described where the first clock domain signal and the second clock domain signals are different, for example having a phase or frequency difference. Furthermore although the following examples show the first device and the second device as sender and receiver respectively it would be understood that in some embodiments each device can be configured to send and receive. Furthermore in some embodiments the system can comprise more than two device configured to communicate to each other. In such embodiments each device communication pairing can comprise a sender and receiver pair as shown in the exampled described herein.
[0074] The sender device 10 can in some embodiments comprise a central processing unit (CPU) 11 configured to generate data and enable the sending of data to the memory 30 shared ring buffer 31 . The CPU 11 can be configured to be any suitable processor.
[0075] The sender device 10 can further comprise a sender memory mapped peripheral (sender MMP) 13 . The sender memory mapped peripheral can be configured to assist in the control of data flow between the sender and the receiver devices. In some embodiments the sender MMP 13 can be configured to receive data request (DREQ) register write information from the CPU 11 , and output a data request (DREQ) to the receiver indicating that the sender requests transferring data to the receiver (in other words that there is data placed in the shared memory for retrieval). The sender MMP 13 can further in some embodiments be configured to receive from a receiver MMP a data acknowledge (DACK) signal indicating that the request has been acknowledged by the receiver device, and to output to the sender CPU 11 a data acknowledgement waiting register signal. In some embodiments the sender MMP further can be configured to receive the data acknowledge (DACK) register write signal.
[0076] The sender device 10 can further in some embodiments comprise a register 15 suitable for storing values to be used by the CPU. The sender register 15 in some embodiments comprises a sender write pointer S:WP, and a sender read pointer S:RP. The sender write pointer S:WP and sender read pointer S:RP define write and read addresses within the share ring buffer 31 detailing the current address of the shared memory for the sender device to write to (the write pointer) and read from (the reader pointer RP). The pointers can in some embodiments be absolute or relative pointers.
[0077] The receiver device 20 can in some embodiments comprise a central processing unit (CPU) 21 . The central processing unit 21 can in some embodiments be a CPU similar to that of the sender CPU 11 , however in other embodiments the receiver CPU 21 can be different from the sender CPU 11 . The receiver CPU 21 can be configured to be suitable for reading from the shared memory.
[0078] In some embodiments the receiver device 20 comprises a memory mapped peripheral (receiver MMP) 23 . The receiver MMP can be configured to receive a data acknowledge (DACK) register write signal from the receiver CPU 21 , and output an acknowledge signal (DACK) to the sender. Furthermore the receiver MMP 23 can be configured to receive the data request (DREQ) signal from the sender device and further be configured to output a request waiting signal (DREQ waiting) to the receiver CPU 21 .
[0079] The receiver device 20 can further comprise in some embodiments a register 25 comprising the receiver read pointer (R:RP). As described herein the receiver read pointer (R:RP) can be configured to contain an address value for the shared memory 30 detailing from which location is the next location to read from.
[0080] With respect to FIG. 2 an example of the sender memory mapped peripheral (sender MMP) 13 is shown in further detail. The sender MMP 13 in some embodiments comprises a first flip-flop (flip-flop A) 101 . The first flip-flop 101 is configured with a clear (CLR) data input, a set (SET) data input, a data output (Q) and a synchronization clock input (>). In the following examples the clear input is given priority over the set input.
[0081] The first flip-flop 101 receives as the set input the data request (DREQ) register write signal. Furthermore the first flip-flop 101 is configured to receive the data acknowledge (DACK) waiting register signal as a clear input. The first flip-flop 101 can be configured to output the data output (Q) to a first AND gate 103 .
[0082] The sender MMP 13 can in some embodiments further comprise an AND gate 103 . The AND gate 103 is configured to receive as a first input the data output of the first flip-flop 101 , and a second input which is an inverted data acknowledgement (DACK) waiting register signal. The output of the AND gate 103 is passed to a first XOR gate 105 .
[0083] In some embodiments the sender MMP 13 comprises a first XOR gate 105 . The first XOR gate 105 is configured to receive as a first input the output of the AND gate 103 and further configured to receive as a second input the output of a fifth flip-flop 113 (flip-flop E). The first XOR gate 105 is further configured to output the XOR′ed logic combination to a second flip-flop 107 .
[0084] The sender memory mapped peripheral 13 in some embodiments further comprises a second flip-flop 107 (flip-flop B) configured to receive as a data input the first XOR gate 105 output. The second flip-flop 107 is further configured to output a synchronized version of the input which is the data request (DREQ) signal passed to the receiver device 20 .
[0085] In some embodiments the sender MMP 13 further comprises a third flip-flop 109 (flip-flop C). The third flip-flop 109 is configured to receive as a data input the data acknowledgement signal (DACK) from the receiver. The third flip flop 109 is configured to output a synchronized or clocked version of the input signal to a fourth flip-flop 111 .
[0086] In some embodiments the sender MMP 13 comprises a fourth flip flop (flip-flop D) 111 . The fourth flip flop 111 is configured to receive as a data input the output of the third flip flop 109 and further configured to output a synchronized or clocked version of the input signal to the fifth flip-flop 113 , and a second XOR gate 115 .
[0087] In some embodiments the sender MMP 13 comprises a fifth flip-flop 113 (flip-flop E) configured to receive as a data input the output of the fourth flip-flop 111 , and configured to output a synchronized or clocked version of the input signal to the first XOR gate 105 and the second XOR gate 115 .
[0088] In some embodiments the sender MMP 13 further comprises a second. XOR gate 115 configured to receive the output of the fourth flip-flop 111 as a first input and the output of the fifth flip-flop 113 as a second input. The second XOR gate 115 is configured to output the XOR′ ed combination to a sixth flip-flop 117 .
[0089] In some embodiments the sender MMP 13 further comprises a sixth flip-flop 117 (flip-flop F). The sixth flip-flop 117 is configured to receive as a set input (SET) the output of the second XOR gate 115 , and configured to receive as a clear input (CLR) a data acknowledgement waiting register write signal (DACK waiting register write). The sixth flip-flop 117 is configured with the set input given priority over the clear input. The output of the sixth flip-flop 117 (Q) is output as the data acknowledgement (DACK) waiting register signal which is output to the CPU, the first flip-flop 101 , and as the inverted input of the AND gate 103 .
[0090] With respect to FIG. 3 an example receiver memory map peripheral (receiver MMP) 23 is shown in further detail. The receiver MMP 23 can in some embodiments comprise a first or toggle flip-flop 201 (flip-flop G). The toggle flip-flop 201 can be configured to receive as its toggle input the data acknowledgement register write signal (DACK register write) received from the receiver CPU 21 . The output of the toggle flip-flop 201 can be output as the acknowledgement signal to the sender (DACK) and an input to a XOR gate 207 .
[0091] In some embodiments the receiver MMU 23 can further comprise a second flip-flop 203 (flip-flop H), configured to receive the request (DREQ) signal from the sender 10 and output a clocked version to a third flip-flop 205 .
[0092] The receiver MMU 23 can further comprise in some embodiments a third flip flop 205 (flip-flop I) configured to receive as a data input the output of the second flip-flop 203 and configured to output a clocked version to the XOR gate 207 .
[0093] The receiver MMU 23 can in some embodiments further comprise a XOR gate 207 configured to receive as a first input the output of the toggle flip-flop 201 and as a second input the output of the third flip-flop 205 . The XOR gate 207 can be configured to output the data request waiting (DREQ waiting) signal to the receiver CPU 21 .
[0094] In the examples herein the sender and receiver MMU flip-flops the clock and reset connections have been omitted for clarity. Furthermore in examples described herein all of the flip-flops are reset to 0 at power up. In such embodiments as described above the flip-flop inputs (set, clear and toggle) are considered to be synchronous inputs.
[0095] In these examples all the sender flip-flops are furthermore clocked using the same ‘sender’ clock source and all the receiver flip-flops are clocked from the same ‘receiver’ clock source. In some embodiments the sender and receiver clock sources can be the same clock source or be substantially the same. However it would be understood that in some embodiments as described herein the clock sources may differ and have phase or frequency differences.
[0096] With respect to FIGS. 4 , 5 , and 6 the operation of the communication between the devices with respect to embodiments of the application is described in further detail.
[0097] With respect to FIG. 4 the operation of communication between the devices up to the passing of the sender data request is described.
[0098] The sender CPU 11 can be configured in some embodiments to write data into the circular buffer (or shared ring buffer 31 ). The sender CPU 11 can for example write data into the circular buffer using the sender write pointer S:WP. The sender CPU 11 furthermore can be configured to ensure that the data does not overflow the buffer by checking that the write pointer S:WP does not pass the read point S:RP for the determined data transfer size.
[0099] The operation of writing data onto the circular buffer is shown in FIG. 4 by step 301 .
[0100] Once the sender CPU 11 has written data into the circular buffer the sender CPU 11 can be configured to determine or calculate how much data is remaining in the buffer. In other words the sender CPU 11 determines the buffer capacity. Where the capacity or available amount of data is greater than the transfer threshold than the CPU 11 can be configured to write to the data request register to send the request to the receiver 20 . The transfer threshold can be any suitable value such as zero in other words the sender CPU can be configured to send a request whenever the buffer is not empty.
[0101] The operation of determining buffer capacity and when checking the capacity being greater than the transfer threshold to write the data request register to write to the data request register to send the request is shown in FIG. 4 by step 303 .
[0102] The data request register write signal being asserted sets the sender MMP first flip-flop 101 to a value of one as the data request register write signal is equal to 1.
[0103] The data request register write signal being asserted setting the flip-flop 101 to 1 operation is shown in FIG. 4 by step 305 .
[0104] The signal then propagates via the AND gate 103 and the XOR gate such that the input of the second flip-flop 107 is inverted and is then propagated at the next clock signal to output a request to the receiver in the form of the DREQ signal being output.
[0105] The operation of outputting the signal DREQ to the receiver is shown in FIG. 4 by step 307 .
[0106] With respect to FIG. 5 the operation of communication between the devices from the outputting of the DREQ signal to the outputting of the DACK signal is shown in further detail according to some embodiments of the application.
[0107] The receiver MMP 23 can be configured to receive the data request (DREQ) signal from the sender 10 where the second flip-flop 203 and the third flip-flop 205 synchronize the request into the receiver clock domain. It would be understood that the number of flip-flops required to synchronize the request can be greater than or fewer than two flip-flops depending on the clock frequencies used for the sender (CPU) and the receiver (CPU). In some embodiments the receiver MMP 23 can be configured to comprise no resynchronization flip-flops, in other words the DREQ signal passes directly to the XOR gate 207 , where the sender and receiver are within the same clock domain or where the process technology is sufficient to allow auto-synchronisation.
[0108] The operation of synchronizing the data request received from the sender into the receiver clock domain is shown in FIG. 5 by step 309 .
[0109] The receiver MMP 23 then can be configured to compare the receiver acknowledgement (DACK) output with the resynchronized request from the sender. This comparison can be performed, as shown in FIG. 3 , by the XOR gate 207 . When the two signals, the receiver acknowledgment (DACK) output, and the resynchronized request from the sender are different the receiver MMP 23 and in particular the XOR gate 207 can be configured to assert the DREQ waiting signal to indicate that a request from the sender is waiting to be serviced. This DREQ waiting signal can in some embodiments be transmitted to the CPU 21 . However the data request waiting signal could be used to interrupt the receiver CPU 21 , made available in a register for reading, or made available as a flag for branching.
[0110] The comparison of the receiver acknowledgement signal with the synchronized data request signal to generate a DREQ waiting signal is shown in FIG. 5 by step 311 .
[0111] The receiver CPU 21 can be configured to receive the request notification (DREQ waiting) and react by reading the agreed amount of data from the shared memory area using the receiver read pointer (R:RP). The receiver CPU 21 can then be configured to update the receiver read pointer (R:RP) to take account of the data that has been read and write to the data acknowledgement register to send an acknowledgement to the sender.
[0112] The operation of receiving the request waiting notification, reading the agreed amount of data, updating the read pointer, and writing to the data acknowledgement register to send an acknowledgement is shown in FIG. 5 by step 313 .
[0113] The writing to the DACK register to send an acknowledgement to the sender causes the data acknowledge register write signal to be asserted, which in some embodiments is received by the toggle flip-flop 201 causing the value of the flip-flop to toggle.
[0114] The operation of asserting the data in a register write signal and toggling the flip-flop 201 is shown in FIG. 5 by step 315 .
[0115] The toggling of the flip-flop 201 causes the output value to be the same as the resynchronised request from the sender de-asserting the data request waiting signal.
[0116] The de-asserting of the data request waiting signal is shown in FIG. 5 by step 317 .
[0117] Furthermore the toggle flip-flop 201 is configured to send the acknowledge signal (DACK) to the sender.
[0118] The outputting of the flip-flop 201 output acknowledge signal to the sender is shown in FIG. 5 by step 319 .
[0119] With respect to FIG. 6 the operation of communication between the devices from the output of the acknowledge signal to the completion of the communications cycle is shown in further detail. The sender MMP 13 can be configured to receive the acknowledge signal (DACK) from the receiver. The acknowledge signal can in some embodiments be resynchronised into the sender clock domain by the third flip-flop 109 and the fourth flip-flops 111 . It would be appreciated that in some embodiments the number of resynchronization flip-flops can be more than or fewer than two flip-flops depending on the clock frequencies of the sender and receiver. Furthermore as described herein the sender can be configured with no resynchronization flip-flops where in embodiments of the application the same clock domain is used for both the sender and receiver or where the process technology allows it.
[0120] The operation of synchronizing the acknowledge signal into the sender clock domain is shown in FIG. 6 by step 321 .
[0121] Furthermore the resynchronized acknowledge signal is passed through the fifth flip-flop 113 and the input and output of the fifth flip-flop 113 can then be compared by the second XOR gate 115 . The second XOR gate 115 thus can be configured to detect a rising or falling edge of the acknowledge signal being received.
[0122] The detection or determination of an acknowledge rising or falling edge is shown in FIG. 6 by step 323 .
[0123] The rising or falling edge detection output then sets the sixth flip-flop 117 .
[0124] The operation of setting the flip-flop 117 is shown in FIG. 6 by step 325 .
[0125] The setting of the flip-flop 117 causes an assertion of the output value, in other words the output of the sixth flip-flop is set to 1. This output value causes the output of the first flip-flop 101 to be cleared, cancelling the effect of the original data request register write (DREQ Reg Write) signal at the first flip-flop 101 which is propagated to the DREQ signal output to the receiver.
[0126] The clearing of the DREQ value and in other words cancelling the request operation is shown in FIG. 6 by step 327 .
[0127] The data acknowledge waiting register signal is also output from the sixth flip-flop 117 . In other words in some embodiments the sender MMP 13 asserts the value of the sixth flip-flop to the sender CPU 11 to indicate that an acknowledgement has been received. This acknowledgement can be used according to some embodiments as an interrupt, register value or flag in a manner similar to the data request signal received at the receiver.
[0128] The operation of outputting the data acknowledge waiting flip-flop signal to the sender CPU 11 is shown in FIG. 6 by step 329 .
[0129] The sender CPU 11 can in some embodiments react to the acknowledge waiting signal by updating the sender read pointer S:RP. In other words the sender CPU 11 frees up the shared memory space occupied by the data the receiver has read.
[0130] The operation of updating the S:RP, is shown in FIG. 6 by step 331 .
[0131] The sender CPU 11 can furthermore in some embodiments recalculate the buffer fill level. Where the amount of data in the buffer is greater than the transfer threshold the sender CPU 11 can be configured to write to the data request (DREQ) register to reassert the date request.
[0132] The operation of re-calculating the buffer capacity and writing to the DREQ register where the capacity is greater than the transfer threshold is shown in FIG. 6 by step 333 .
[0133] This operation enables further cycles of generating DREQ and DACK signals.
[0134] The advantages of these embodiments of the application are that there is a minimisation of the number of connections required (only one signal in each direction). Furthermore in some embodiments the operation is tolerant of any amount of latency in the request or acknowledgement signals.
[0135] In these embodiments the sender can place as many transfers worth of data into the buffer without the receiver being required to remove any of the data provided that the buffer is large enough. Furthermore in some embodiments multiple requests do not cancel each other out.
[0136] The senders CPU according to some embodiments can be further be allowed to be recalculate and reassert the request safely at any time without causing the receiver to receive a spurious request. For example where the sender attempts to reassert the request whilst an acknowledgement is waiting the request is ignored because the waiting acknowledgement overrides the request.
[0137] It would be understood that while the read and write pointer management can be performed by software running on the CPUs the embodiments of the application can be extended to include automatic pointer management hardware.
[0138] Furthermore although the above description describes where the control of a shared memory is performed the operations and designs in communicating predetermined commands from one CPU to another can also be implemented using embodiments of the application.
[0139] In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.
[0140] Embodiments may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD.
[0141] The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), gate level circuits and processors based on multi-core processor architecture, as non-limiting examples.
[0142] Embodiments may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.
[0143] Programs, such as those provided by Synopsys, Inc. of Mountain View, Calif. and Cadence Design, of San Jose, Calif. automatically route conductors and locate components on a semiconductor chip using well established rules of design as well as libraries of pre-stored design modules. Once the design for a semiconductor circuit has been completed, the resultant design, in a standardized electronic format (e.g., Opus, GDSII, or the like) may be transmitted to a semiconductor fabrication facility or “fab” for fabrication.
[0144] The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention as defined in the appended claims.
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A processor module including a processor configured to share data with at least one further processor module processor; and a memory mapped peripheral configured to communicate with at least one further processor memory mapped peripheral to control the sharing of the data, wherein the memory mapped peripheral includes a sender part including a data request generator configured to output a data request indicator to the further processor module dependent on a data request register write signal from the processor; and an acknowledgement waiting signal generator configured to output an acknowledgement waiting signal to the processor dependent on a data acknowledgement signal from the further processor module, wherein the data request generator data request indicator is further dependent on the data acknowledgement signal and the acknowledgement waiting signal generator acknowledgement waiting signal is further dependent on the acknowledgement waiting register write signal.
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This application is a division of Ser. No. 682,650 filed Dec. 17, 1984, now U.S. Pat. No. 4,596,850; which is a division of Ser. No. 715,218 filed Mar. 22, 1985, issued Mar. 18, 1986 as U.S. Pat. No. 4,577,031; which is a continuation of Ser. No. 473,922 filed Mar. 10, 1983, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to novel polymerizable imidazolidinone monomers, their preparation, and their use to form self-crosslinking polymers which are thermosettable without the release of formaldehyde. It also relates to the use of such polymers in emulsion form as non-woven binders.
It is well-known in the art to employ self-crosslinking polymers, either in emulsion or solution form, as coatings, binders, or adhesives for a variety of substrates. Self-crosslinking polymers are distinguished from crosslinkable polymers in that the latter contain a functionality, such as a carboxyl group, which can only be crosslinked by the addition of a co-reactant (i.e., crosslinker) to the polymer emulsion or solution. A typical crosslinkable system can be represented as follows: ##STR4##
In contrast, self-crosslinking polymers contain a functionality which is self-reactive and consequently do not require the use of a coreactant species per se. A typical self-crosslinking system can be represented as follows: ##STR5##
The advantages of the self-crosslinking polymer systems are their simplicity, economy, and particularly their efficiency. Such systems have been used as textile adhesives, non-woven binders, pigment binders for glass fabrics, and fabric finishing agents for hand and weight modification. On curing, such systems produce textile products with excellent durability to washing and dry cleaning. They have also been used in pigment printing and dyeing and as a binder for paper.
Both the self-crosslinking and crosslinkable polymer systems of the prior art suffer from the disadvantage that toxic free formaldehyde is present either during the curing or the preparation of the polymers. The self-crosslinking systems, which are typically formaldehyde-amide polymeric adducts containing methylolacrylamide repeating units, liberate formaldehyde during curing of the crosslinked thermoset polymer. The crosslinkable systems, which are typically based on urea-formaldehyde or melamine-formaldehyde resins and crosslinkers, may contain residual free formaldehyde.
In addition to the odor problems created by the presence of free formaldehyde, the dermatitic effect is a serious problem. The exposure of operating personnel and consumers to formaldehyde has been a recent concern of both industry and regulatory agencies. This has lead to the search for formaldehyde-free systems, especially self-crosslinking, formaldehyde-free systems for use as nonwoven binders.
SUMMARY OF THE INVENTION
The present invention provides, as a composition of matter, an imidazolidinone of the general structure: ##STR6## wherein R 1 is hydrogen or a C 1 -C 6 linear or branched alkyl group; X is a divalent radical selected from the group consisting of --(CH 2 ) m --, ##STR7## with R being hydrogen or a methyl group, with m being an integer from 0 to 5, and with n being an integer from 1 to 5, preferably m or n being 1; R 2 is hydrogen or a methyl group; R 3 is hydrogen or a ##STR8## group with R 7 being hydrogen or a linear or branched C 1 -C 6 alkyl or hydroxyalkyl; and R 4 and R 5 are independently hydrogen or a linear or branched C 1 -C 4 alkyl group.
It also provides homopolymers and polymers thereof with monomer(s) containing at least one ethylenically unsaturated group.
In a preferred embodiment it provides emulsion (latex) polymers containing about 1-15%, preferably 3-6%, by weight of the above monomers and about 85-99%, preferably 94-97%, of an ethylenically unsaturated monomer, such as ethylene, vinyl acetate, ethyl acrylate, butyl acrylate, methyl methacrylate and the like, for use as formaldehyde-free binders for nonwoven textiles. A typical polymer contains about 45-60% vinyl acetate, 34-52% butyl acrylate, and about 3-6% of the self-cross-linking imidazolidinone.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The novel monomers herein are typically prepared by reacting an ethylenically unsaturated urea derivative with glyoxal. The urea derivatives are usually well known compounds previously reported in the chemical literature. Methods for their preparation are described in Synthetic Organic Chemistry by R. B. Wagner and H. D. Zook, John Wiley & Sons, 1963, p. 645. Two suitable methods include the reaction of isocyanates with amines, i.e. ##STR9## wherein R or R' may be an unsaturated group, and the reaction of amines with urea, i.e. ##STR10## wherein R" is an unsaturated group.
In the typical isocyanate reaction, the isocyanate compound is dissolved in an aprotic dry solvent such as toluene at about 40% concentration. The entire reaction system is protected from moisture by suitable drying tubes, inert gas purge, or the like. The amine is slowly added to the solution at a temperature not exceeding 10°-15° C. In the case of ammonia or simple alkyl amines, this component is a gas and it is bubbled subsurface. The reaction is exothermic and adequate cooling may be required. The urea derivative usually precipitates as it forms and may be recovered from the reaction mixture by filtration. The derivative is then washed and dried.
In the typical amine reaction, the amine and urea are combined and heated at 120°-150° C. with the evolution of ammonia. When the reaction mixture reaches the required weight, the heating is stopped and the solid mass is recrystallized to recover the urea derivative.
In the imidazolidinone preparation, the urea compound is dissolved in sufficient water and gloxal to provide a solution of about 50% theoretical solids (based on imidazolidinone being prepared). The glyoxal reagent, used in stoichiometric amounts, may vary in form (e.g. 40% aqueous solution, 80% powder, p-dioxane diol, or the like). The pH of the mixture is adjusted to 7-7.5 with sodium hydroxide. Heat is applied to raise the temperature of the mixture to 45°-80° C. to effect complete reaction. The reaction is monitored by titrating for glyoxal content. When the reaction is complete, the monomer solution is generally diluted to 40% solids by the addition of water and the diluted mixture treated with activated charcoal. When the hydroxyl groups of the imidazolidinone ring are substituted with alkyl groups, suitable starting materials for the imidozolidinones may be prepared using well-known methods described in Synthesis 243 (1973a).
The above imidazolidinone monomers are useful as vinyl polymerizable monomers (i.e. monomers polymerizable by vinyl type polymerization procedures). They may be used to form homopolymers or their mixtures may be used to form polymers thereof. They may also be used to form addition polymers with other ethylenically unsaturated monomers. The polymers may be prepared by solution, emulsion, precipitation, suspension, or bulk polymerization techniques. The preferred method is emulsion polymerization.
Suitable comonomers include one or more monomers containing at least one ethylenically unsaturated group such as (meth)acrylonitrile; (meth)acrylic acid and the esters, amides and salts thereof; itaconic acid and its functional derivatives, preferably the esters; maleic anhydride; maleic and fumaric acids and the esters thereof; vinyl ethers and esters; styrene; ethylene; vinyl and vinylidene chlorides; and the like.
The preferred addition polymers for use as formaldehyde-free binders for non-woven textiles are polymers containing about 1-15%, preferably 3-5%, by weight of the above imidazolidinone monomers and about 99-85%, preferably 97-95%, by weight of one or more ethylenically unsaturated monomers such as ethylene, vinyl acetate, ethyl acrylate, butyl acrylate, or methyl methacrylate. The preferred imidazolidinone monomers for this use include 3-(methacryloxyethyl)-4,5-dihydroxy-2-imidazolidinone, 1-ethyl-3-allyl-4,5-dihydroxy-2-imidazolidinone, and 3-allyl-4,5-dihydroxy-2-imidazolidinone.
The following examples will more fully illustrate the embodiments of this invention. In the examples, all parts and percentages are given by weight and all temperatures are in degrees Celsius unless otherwise noted.
EXAMPLE I
This example describes the preparation of the 3-(methacryloxyethyl)-4,5-dihydroxy-2-imidazolidinone (MEDHEU). The two-step reaction sequence was as follows: ##STR11##
A three liter round bottom flask equipped with a thermometer agitator, condenser, drying tube and a gas inlet tube was charged with 1500 ml. of 3A° sieve dried toluene and 340 g. (2.195 moles) of β-isocyanatoethyl methacrylate. With agitation, the mixture was cooled to 5° C. in an ice bath. While maintaining the reaction temperature at 5°-10° C., 39.6 g. ammonia gas was bubbled subsurface over a period of 7 hrs. After the addition was completed, the temperature of the reaction mixture was allowed to rise to 25° C. The precipitated urea product was recovered by filtration, washed with fresh toluene, and dried in a vacuum dessicator to constant weight. Yield was 369 g. (98%). IR analysis (1715 cm -1 , 1685 cm -1 , 1600 cm -1 ) and nitrogen analysis (16.3%) were consistent with the mono-substituted urea structure of N-methacryloxyethyl urea.
A one-liter four neck flask equipped with an agitator, thermometer, condenser and pH electrode/meter was charged sequentially with 13 g. distilled water, 95.6 g. of 43.6% aqueous glyoxal solution, 0.25 g. monomethyl ether of hydroquinone, and 125 g. of the above urea. The mixture was agitated until complete solution was achieved. The pH of the mixture was adjusted to 7.0-7.5 with 6.25N NaOH (25% W/V) and the mixture was heated at 60° C. for 5 hr. At the end of this period, analysis for glyoxal indicated 95% reaction. The mixture was diluted with 597 g. distilled water, purified by slurrying with 8.3 g. of a high surface area activated charcoal, and filtered through diatomaceous earth. The active solids content was 20% MEDHEU.
EXAMPLE II
This example describes the preparation of 1-ethyl-3-allyl-4,5-dihydroxy-2-imidazolidinone (EADHEU). The two-step reaction sequence was as follows: ##STR12##
A two-liter reactor equipped with an agitator, thermometer, condenser with drying tube and equalized dropping funnels was charged with 800 ml. of sieve dried toluene and 80 g. allyl amine. With agitation, the mixture was cooled to 10° C. and 100 g. of ethylisocyanate was added over a 2 hr. period. The reaction was exothermic and the temperature was maintained at 10°-15° C. throughout the addition by external cooling. After the addition was completed, the toluene was vacuum distilled from the mixture at 40° C./20mm. Hg. The viscous liquid was titurated with heptane to precipitate the N-ethyl, N'-allyl-urea. The nitrogen content was 21.3% (21.5% theoretical).
A 500 ml. flask equipped with a thermometer, condenser, and agitator was charged with 75 g. of the above urea, 97.1 g. of 43% aqueous glyoxal, and 87.5 g. distilled water. After complete dissolution of the reactants, the pH was adjusted to 7.0-7.5 with 25% sodium hydroxide and the mixture heated at 80°-85° C. for 4.5 hr. The glyoxal content was monitored during the reaction period. At the end of the heating period, no glyoxal was detected, indicating 100% reaction. The mixture was diluted with water and purified as before. The active solid content was 26.5% EADHEU.
Carbon-13 NMR analysis of the aqueous solution confirmed the presence of the imidazolidinone ring structure. The chemical shifts were as follows:
______________________________________Oc ppm Pattern Assignment______________________________________ 12.9 Quartet ##STR13## 35.3 Triplet ##STR14## 42.5 Triplet ##STR15## 84.3 Doublet ##STR16##117.0 Triplet ##STR17##132.8 Doublet ##STR18##158.8 Singlet ##STR19##______________________________________
EXAMPLE III
This example illustrates the preparation of additional imidazolidinone monomers using the procedure of Example II.
Part A
3-Allyl-4,5-dihydroxy-2-imidazolidinone (ADHEU) was prepared using 93.5 g. N-allyl urea, 109 g. 43% aqueous glyoxal, and 60 g. distilled water. The reaction was carried out for 6 hr. at 45°-50° C. Yield was 87%. The active solid content was 43.6%. The monomer had the following structure: ##STR20##
Part B
1-Methyl-3-(methacryloxyethyl)-4,5-dihydroxy-2-imidazolidinone was prepared using 37.2 g. N-methyl-N'-methacryloxyethyl urea, 25.7 g. 43% aqueous glyoxal, and 6 g. water. The reaction was carried out for 6.5 hr. at 60° C. Yield was 94%. The mixture was diluted with 124 g. distilled water. The active solids content was 25%. The monomer had the following structure: ##STR21##
Part C
1-Butyl-3-(2-methyl-1-propenyl)-4,5-dihydroxy-2-imidazolidinone was prepared using 85 g. N-butyl-N'-(2-methyl-1-propenyl) urea, 36.3 g. 80% aqueous glyoxal, and 106 g. water. The reaction was carried out for 8 hr. at 80° C. Yield was 100%. The mixture was diluted with 58 g. distilled water. The active solids content was 39.5%. The monomer had the following structure: ##STR22##
This example describes the preparation of 3-(β-hydroxyethyl-2-maleoxyethyl)-4,5-dihydroxy-2-imidazolidinone (EMDHEU). The three-step reaction sequence was as follows: ##STR23##
A two-liter round bottom flask, fitted with an agitator, thermometer, condenser, and dying tube, was charged with 1000 ml. of sieve dried toluene, 208 g. (2.0 moles) of β-hydroxyethyl urea and 196 g. (2.0 moles) of maleic anhydride. The reaction mixture was heated to 85°-90° C. Initially the mixture formed two distinct immiscible liquid phases. As the reaction proceeded, the mixture became homogeneous. Heating was continued until infrared analysis showed complete disappearance of the anhydride bands and the acid number of the reaction mixture indicated complete reaction (280 mg. KOH/gm. sample actual vs. 277 theory). The toluene was removed by vacuum stripping. A total of 393.5 g. (97.5% yield) of N-(2-maleoxyethyl) urea was obtained.
While maintaining the above reaction mixture at 80°-85° C., 0.9 g. Na 2 CO 3 was added and the subsurface addition of ethylene oxide (115 g.) was carried out over 6 hours. At the end of the ethylene oxide addition, the acid number was 28 corresponding to a reaction efficiency of 91%. The residual ethylene oxide was removed by a brief vacuum stripping at 80° C. A total of 464 g. of N-(β-hydroxyethyl-2-maleoxyethyl) urea having an acid number of 15 (corresponding to 95% reaction) was obtained.
The above reaction mixture was cooled to 30° C. and 100 g. distilled water and 254 g. of 43% aqueous glyoxal were added. It was adjusted to pH 7.0-7.5 with 25% W/V sodium hydroxide and heated at 60° C. for 2 hr. After this time no glyoxal was detected in the reaction mixture. It was diluted to 20% solids with 1917 g. water, treated with charcoal and filtered. Yield was 100%.
EXAMPLE V
This example describes the preparation of 3-(methacryloxy-2-hydroxypropoxyethyl)-4,5-dihydroxy-2-imidazolidinone (MPEDHEU). The two-step reaction sequence was as follows: ##STR24##
A 500 ml. round bottom reaction flask fitted with a thermometer, condenser and agitator was charged with 142 g. (1 mole) of glycidyl methacrylate, 0.25 g. monomethyl ether of hydroquinone, 0.75 g. tetramethyl ammonium chloride and 104 g. β-hydroxyethyl urea (1.0 mole). The mixture was heated and stirred at 80°-85° C. until gas-liquid chromatographic (GLC) analysis indicated complete consumption of the glycidyl methacrylate (about 6 hrs.). This is always indicated by testing the water solubility of the reaction mixture. The product is water soluble and near completion of the reaction no turbidity is observed in test samples. The reaction mixture was then cooled to 30° C. and 132 g. of water were added.
A portion of the above reaction mixture containing 154 g. of N-(methacryloxy-2-hydroxypropoxyethyl) urea (0.407 moles) was charged to a 250 ml. reaction vessel equipped with a stirrer, thermometer, and condenser. To this was added 27.7 g. of glyoxal trimer (0.397 mole-83% active) and 7.5 g. distilled water. The pH of the mixture was adjusted to 7.0-7.5 with 25% W/V NaOH and the mixture was heated at 65° C. for 3 hr. The glyoxal content was 0% indicating 100% reaction. The reaction mixture was treated with 4 gms. of activated carbon and filtered. The active solids content was 40%.
EXAMPLE VI
This example describes the preparation of 3-(1-propenoxy-2-hydroxypropoxyethyl)-4,5-dihydroxy-2-imidazolidinone.
The reaction was carried out in a similar manner to that of Example V except that 114 g. allylglycidyl ether (1 mole) was used in place of the glycidyl methacrylate and 135 g. (1 mole) of 43% aqueous glyoxal was used instead of the 83% aqueous glyoxal trimer. The active solids content was 45%. The monomer had the following structure: ##STR25##
EXAMPLE VII
This example describes the preparation of 3-allyl-4,5-dimethoxy-2-imidazolidinone.
A mixture of 100 g. of N-allyl urea (1 mole), 69.9 g. of 83% glyoxal (1 mole), and 750 g. methanol is stirred for 1 hr. at 35°-40° C. A total of 50 g. of a cation exchange resin (sulfonated polystryrene, H + form, 5.2 meq./dry g.) is then added. The mixture is stirred for 1 hr. at relux (about 70° C). The catalyst is removed by filtration, and the reaction mixture is concentrated by vacuum distillation of the solvent. The resulting product should be 232 g. of a syrup at 80% active solids (based on 100% yield). The monomer will have the following structure: ##STR26##
EXAMPLE VIII
This example describes the preparation of 1-ethyl-3-vinyl-4,5-dihydroxy-2-imidazolidinone.
A total of 172 g. of N-vinyl-N'-ethyl urea (1 mole), prepared as described in J. Poly. Science, Part A-1, Vol. 7, 35-46 (1969), is dissolved with stirring in 200 g. distilled water. To this solution is added 69.9 g. 83% glyoxal (1 mole). The pH of the mixture is adjusted to 7.5 with 0.5N NaOH, and the mixture is heated at 70° C. for 4.5 hr. or until a determination of the glyoxal content indicates complete conversion. The mixture is diluted with 133 g. distilled water and 0.23 g. monomethyl ether of hydroquinone. The diluted mixture is treated with 2 g. activated charcoal and filtered. The final product should be an aqueous solution of the monomer at 80% solids (based on 100% yield). The monomer will have the following structure: ##STR27##
EXAMPLE IX
This example describes the preparation of a surfactant-stabilized latex polymer containing 58.9% vinyl acetate, and 35.3% butyl acrylate, 5.8% of the MEDHEU monomer of Example 1. It also describes its evaluation after crosslinking and its use as a binder for non-woven textiles.
Part A
A two-liter four neck flask was fitted with a thermometer, condenser, agitator, subsurface nitrogen purge, and suitable addition funnels. To the flask was added:
400 g. distilled water
2.0 g. 20% sodium dodecyl benzene sulfonate
2.5 g. 70% ethoxylated nonyl phenol (30 moles EO)
0.5 g. sodium acetate
0.8 g. sodium persulfate
The mixture was purged subsurface th nitrogen at a rapid rate for 15 min. The gas rate was then reduced, and 50 g. vinyl acetate and 5 g. butyl acrylate were added. Agitation was started.
A monomer pre-emulsion was prepared by combining the following ingredients in a beaker and subjecting the mixture to high speed mixing: 125 g. of the MEDHEU monomer @ 20%; 10 g. of 30 mole ethoxylated nonyl phenol @ 70%; 12 g. of 20% sodium dodecyl benzene sulfonate; 200 g. vinyl acetate; 145 g. butyl acrylate. The mixture was transferred to a one-liter dropping funnel. A catalyst solution, designated S-2, was prepared by dissolving 0.7 g. sodium persulfate in 30 g. distilled water.
The initial reactor charge was heated to 72°-75° C. The mixture began to reflux at 72° C. Polymerization was indicated by a change in the mixture's appearance. After the refluxing stopped, the monomer pre-emulsion (S-1) and the catalyst solution (S-2) were slowly added to the reactor over a 4 hr. period at 72°-75° C. After the addition was complete, the batch was held for 1 hr. at 75° C., cooled, and discharged.
The resulting latex had a solids content of 48%. Yield was 98%. The properties of the latex were as follows: a pH of 4.1; intrinisic viscosity of 0.90 dl./g. in dimethyl formamide (DMF); Brookfield viscosity of 175 cps.; particle size of 0.17 nm.; and unfiltered grit (200 mesh) of 40 ppm. No formaldehyde was detected (the detectable limit was 5 ppm).
Part B
In order to evaluate the self-crosslinking capabilities and formaldehyde content of the above latex polymer, films were drawn on polyethylene as uncatalyzed or catalyzed (0.5% oxalic acid on polymer solids) latices. The films were air dried overnight or cured by heating in a forced air draft oven at 130° C. for 5 min. The film specimens were then weighed into enough DMF to make a 1% solution and refluxed for 2 hours. The cooled mixture was filtered, and the amount of soluble polymer was determined by oven solids. A determination of % insolubles was then made. A comparison polymer containing 3% N-methylolacrylamide (NMA), a known self-crosslinking monomer was also evaluated.
______________________________________ Comparison Latex Invention Latex (containing NMA) (containing MEDHEU)______________________________________Formaldehyde on 3400 ppm NonelatexInsolubles - air 38% 45%driedInsolubles - cata- 64% 70%lyzed and air driedInsolubles - cata- 89% 90%lyzed and ovencured______________________________________
The results show the latex containing the self-crosslinking imidazolidinone-containing polymer of the present invention contained no formaldehyde and that it crosslinked as efficiently as the comparison latex containing the self-crosslinking polymer of the prior art.
Part C
The above latex polymers were evaluated as binders for non-woven textiles.
A substrate web of 100% polyester fiber was prepared by carding and subsequently lightly thermally bonded. The latex containing the MEDHEU polymer was formulated with 1% (dry basis) zinc chloride catalyst. The comparison latex containing the NMA polymer was formulated with 0.5% oxalic acid. The binders were diluted with water to 15% solids. The web was passed through a bath saturated with the binder formulation and squeezed through nip rolls to remove excess binder. Binder add-on was controlled to 40%±4% dry binder, based on fiber weight. This range was equivalent to 26-31% binder on total fabric weight and provided a finished fabric weighing approximately 20 gms./sq. yd. The aturated web was dried on a rotary drum dryer at 120° C. and then cured for 2 min. at 150° C. in a forced air oven. Specimens were tested for wet strength (soaked 5 min. in a 0.5% Aerosol OT solution) and dry strength in the cross machine direction (CD).
______________________________________Fabric Treatment Strength % Basis (lbs./linear inch)Latex Pickup Wt. CD Wet CD Dry______________________________________MEDHEU Polymer Latex 44 20.1 1.18 1.94NMA Polymer Latex 40 20.8 1.27 1.83(comparative)______________________________________
The results show that the formaldehyde-free binder containing the self-crosslinking imidozolidinone-containing polymer provided a non-woven textile of comparable wet and dry strength to that prepared using the prior art NMA-containing polymer that self-crosslinks with the release of formaldehyde.
EXAMPLE X
This example describes the preparation of a latex polymer of 82% vinyl acetate, 15% ethylene, and 5% of the EMDHEU monomer of Example IV.
A 1-liter stirred autoclave was charged with 213.5 g. distilled water, 0.011 g. FeSO 4 , 0.1% in water, 0.057 g. of a 75% solution of sodium dioctyl sulfosuccinate, 1.44 g. of a 80% solution of sodium dihexyl sulfosuccinate, 0.18 g. sodium acetate, and 2.28 g. acetic acid. The reactor was purged and evacuated with nitrogen three times. After purging, 35 g. vinyl acetate was loaded into the reactor. It was pressurized to 500 psi with ethylene and agitation was started.
A monomer pre-emulsion, designated S-1, was prepared by mixing with high speed agitation 85 g. distilled water, 0.5 g. calcium acetate, 5.0 g. partially ethoxylated phosphoric acid, 5.0 g. ethoxylated nonylphenol (40 moles EO), 50.0 g. MPEDHEU monomer at 20% solids, and 245.0 g. vinyl acetate.
Catalyst solutions, designated S-2 and S-3 respectively, were prepared by mixing 1.31 g. sodium persulfate and 17.5 g. distilled water and by mixing 0.52 g. sodium formaldehyde sulfoxylate and 17.5 g. distilled water.
The reactor contents were heated to 40° C. under 500 psi ethylene pressure. At temperature, the monomer pre-emulsion S-1, the oxidant S-2 and the reductant S-3 were added over a 6 hr. period. The reaction temperature was allowed to rise to 70° C. and was maintained at that temperature during the entire polymerization. At the end of the addition, the pressure source was isolated and the reactor pressure was allowed to drop over 2 hr. while maintaining the mixture at 70° C. The reactor was then cooled and the resultant latex discharged.
The latex was 41.1% solids. Conversion was 99%. The latex had the following properties: a pH of 4.2; intrinsic viscosity of 2.44 dl./g. in DMF; Brookfield viscosity of 25 cps.; particle size of 0.19 mm; and grit (200 mesh) of 20 ppm unfiltered. The Tg of the polymer was +3° C.
EXAMPLE XI
Using procedures outlined in Examples IX and X, latex polymers of 48.5% vinyl acetate, 48.5% butyl acrylate, and 3% of the indicated imidazolidinones were prepared. All values are based on 100 parts of the major monomer component and are expressed as active ingredient.
The initial charge was prepared by mixing 76.6 parts distilled water, 0.155 parts of a 31% solution of disodium ethoxylated alcohol half ester of sulfosuccinic acid, 0.42 part of a 70% solution of ethoxylated octyl phenol (30 mole EO), 10 parts vinyl acetate, 1 part butyl acrylate, 0.12 part ammonium persulfate, and 0.04 parts sodium acetate.
The monomer pre-emulsion was prepared from 15.7 parts distilled water, 40 parts vinyl acetate, 49 parts butyl acrylate, 3 parts of the imidazolidinone monomer described hereafter, 0.62 part disodium ethoxylated half ester of sulfosuccinic acid, and 0.7 part of a 70% solution of ethoxylated octyl phenol (30 mole EO). The catalyst used was prepared from 8 parts distilled water and 0.16 part ammonium persulfate.
Latex A prepared using the EADHEU monomer of Example II had a solids content of 48.3%. Conversion was 98%. It had a pH of 3.9; intrinsic viscosity of 1.524 dl./g. in DMF; viscosity of 30 cps.; particle size of 0.25 mm.; and grit (200 mesh) of 60 ppm. unfiltered. The % insolubles uncured (air-dried) and cured were 45 and 90%, respectively.
Latex B prepared using the EMDHEU monomer of Example IV had a solids content of 48.2%. Conversion was 98%. It had a pH of 4.2; intrinsic viscosity of 1.19 dl./g. in DMF; Brookfield viscosity of 77 cps.; particle size of 0.15 mm.; and grit (200 mesh) of 30 ppm. unfiltered. The % insolubles uncured and cured were 11 and 75%, respectively.
EXAMPLE XII
This example describes the preparation of a latex polymer of 87.4% ethyl acrylate, 9.7% methyl methacrylate, and 2.9% of the ADHEU monomer of Example III--Part A. The polymerization procedure previously described was used.
The initial charge was prepared from 71.0 parts distilled water, 0.20 part sodium dodecylbenzene sulfonate, 0.40 part of ethoxylated octyl phenol (30 mole EO), 10 parts ethyl acrylate, and 0.15 part ammonium persulfate. The monomer pre-emulsion was prepared from 13.1 parts distilled water, 80.0 parts ethyl acrylate, 10.0 parts methyl methacrylate, 0.6 part sodium dodecylbenzene sulfonate, and 1.55 parts of ethoxylated octyl phenol (30 mole EO). The self-crosslinking functional monomer solution consisted of 3 parts of the ADHEU monomer and 12.2 parts water. The catalyst solution contained 10 parts water, 0.2 part ammonium persulfate, and 0.1 part sodium bicarbonate.
The resulting latex had a solids content of 47.7%; a pH of 3.2; intrinsic viscosity of 0.603 dl./g. in DMF; Brookfield viscosity of 400 cps.; particle size of 0.17 mm.; and grit (200 mesh) of 10 ppm. The conversion was 95.8%.
EXAMPLE XIII
This example describes the prepration of a polyvinyl alcohol-stabilized latex polymer of about 97.1% vinyl acetate and 2.9% of the MEDHEU monomer of Example 1.
A 2-liter reactor was charged with an initial mixture of 288 parts distilled water, 6 parts medium viscosity 88% polyvinyl alcohol, 9 parts high viscosity 88% polyvinyl alcohol, 0.46 parts ammonium persulfate, and 50 parts vinyl acetate. The mixture was heated to reflux (about 72° C.). To the heated mixture were slowly added a pre-emulsion of 90.9 parts distilled water, 0.2 parts medium viscosity 88% polyvinyl alcohol, 75.0 parts of the MEDHEU monomer (20%), 0.45 parts high viscosity 88% polyvinyl alcohol, and 45 parts vinyl acetate and a catalyst solution of 26.5 parts distilled water, 0.75 parts 28% ammonium hydroxide solution, and 0.25 parts ammonium persulfate. The pre-emulsion and catalyst solution were added at a rate sufficient to maintain reflux (over about 3 hr.). After the addition was completed, the batch was cooled and discharged. The resulting latex had a solids content of 52.3%, a pH of 4.6, and Brookfield viscosity of 7000 cps.
Now that the preferred embodiments of the invention have been described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present invention are to be limited only by the appended claims, and not by the foregoing specification.
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Novel polymerizable imidazolidinone monomers, useful in the preparation of self-crosslinking polymers, have the general structure ##STR1## wherein R 1 is H or a C 1 -C 6 linear or branched alkyl or hydroxyalkyl group; X is a divalent radical selected from the group consisting of --(CH 2 ) m --, ##STR2## with R being H or CH 3 , m being 0-5, and n being 1-5; R 2 is H or CH 3 ; R 3 is H or ##STR3## with R' as defined above; and R 4 and R 5 are independently H or linear or branched C 1 -C 4 alkyl groups. In a preferred embodiment, aqueous emulsions of the imidazolidinone-containing polymers (e.g. 45-60% vinyl acetate, 34-52% butyl acrylate, and 3-6% imidazolidinone) and an acid-curing catalyst (e.g. ZnCl 2 ) are used as formaldehyde-free binders for nonwoven textiles.
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FIELD OF THE INVENTION
This invention relates to rail vehicle braking systems and relates especially to improvements to such systems as applied to a train of vehicles.
BACKGROUND AND SUMMARY
In rail vehicle braking systems it has become established practice to employ air under pressure in a brake pipe running the length of a train as the control means whereby brakes are applied and released. More specifically, it has been preferable to establish a system pressure, a decrease in which pressure in the brake pipe gives rise to a brake application, and a subsequent recovery of which permits the release of the brakes.
The use of air under pressure for control of the brakes in the above manner has certain shortcomings in a long train because not only can the rate of propagation of a pressure signal be no greater than the speed of sound but more significantly, where the system relies upon a reduction of brake pipe pressure by passing air from one end of the train to another through the brake pipe, the resistance to such flow of air through the brake pipe can introduce substantial delays between the operation of the brakes on spaced vehicles of the train. The present invention seeks to advantageously reduce the above more significant shortcoming.
According to the present invention there is provided in a rail vehicle braking system an arrangement for improving brake signal propagation in a brake pipe, the arrangement including a valve and a fluid flow sensor connected into a section of a brake pipe and to be responsive to flow rate in the brake pipe, said valve being responsive to the flow sensor to effect enhancement of a brake pipe pressure change produced by flow therein. The arrangement preferably is constructed so as to effect the enhancement only upon the occurrence of a predetermined pressure change to be propagated in the pipe, so as to render the arrangement non-responsive to pressure changes of other than a predetermined sense and to steady pressure gradients and flow as might be caused by a leak in the system, thus responding only to predetermined changing pressures in the brake pipe.
In a braking system, one or more said arrangements may be included at the points based along the brake pipe of a train from a brake pipe control valve and thereby reduce delays in response of the brakes along the train.
BRIEF DESCRIPTION OF DRAWING
In order that the invention may be more clearly understood and readily carried into effect, the same will be further described by way of example with reference to the accompanying drawing which illustrates in schematic form a relevant part of a brake system utilising the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawing, a heavy conduit denoted by the reference 1 represents a portion of the brake pipe of a train, being a portion which is provided on one vehicle of a train. Connected into this portion of the brake pipe between the points A and B there is provided a restriction denoted by the reference 2 which is sufficient to provide a perceptible pressure drop when a reduction of brake pipe pressure is effected such as to give rise to an appreciable flow of air between the points A and B. This perceptible pressure drop is such as to be responded to by a pressure sensitive device 3, to which connections 4 and 5 are made to either side of the restriction 2. The pressure sensitive device 3 essentially comprises a main body 6 which is divided into two chambers 7 and 8 by means of a flexible diaphragm 9. This diaphragm 9 is such that when the pressure in the chamber 7 exceeds that in the chamber 8, it bears against an orifice 10 to close the orifice in the manner of a valve thereby preventing the flow of fluid from the chamber 8 to an output conduit connected to the orifice 10. For reasons to be referred to hereafter, the pressure sensitive device 3 also includes a piston operable plunger 11, operation of which is effective to maintain the diaphragm in a position in which it maintains the orifice 10 closed. The piston is denoted by the reference 12 and this is provided with a light spring such that in the absence of applied pressures, the plunger 11 is urged against the diaphragm. Output pressure derived from the orifice 10 is applied via a conduit 14 and a choke 29 to atmosphere and also to a control input of a vent valve 15. The vent valve is of conventional construction and merely comprises a spring loaded diaphragm operable valve member 16 which is normally urged by its spring 17 into the closed position against a valve seat 18. The valve seat 18 communicates with the brake pipe via a conduit 19 and the other side of the valve seat communicates with atmosphere via a conduit 20. The vent valve is thus such that on application of a suitable pressure via the conduit 14, the vent valve opens to provide communication via conduits 19 and 20 to atmosphere thereby venting the brake pipe for as long as the necessary pressure exists at the conduit 14. A further pressure responsive device is denoted by the outline 3a and a further vent valve is denoted by the outline 15a and it will be noted that whilst the pressure responsive device 3a is connected across the restriction 2 in a manner similar to the device 3, the vent valve 15a is connected on the other side of the restriction 2 as compared to the vent valve 15.
One further unit is shown in the drawing and this comprises a device 21 which in operation inhibits the operation of either of the vent valves 15 and 15a in the event of the existence of rising pressure in the brake pipe, or in the event of steady flow or pressure gradients, i.e., when pipe pressure is not actually changing. This latter device 21 comprises a diaphragm 22 separating two chambers 23 and 24, the former of which communicates via a tube 25 with the front of the piston of each of the pressure responsive devices 3 abd 3a. The chamber 23 also communicates via a choke and suitable conduit with the brake pipe. The other chamber 24 of the device 21 communicates via suitable conduit also with the brake pipe.
Whilst in the foregoing a restriction 2 is actually inserted in the brake pipe, it is to be understood that by making the connections between more widely spaced points in the brake pipe sufficient pressure drop may be able to be sensed due to flow in the brake pipe without the provision of the actual restriction and the operation now to be described should be taken having this in mind.
In operation of the apparatus as shown in the drawing, it will be assumed that the locomotive from which the brakes are to be controlled is connected to the section of brake pipe which joins the section AB at the point A. That is, the locomotive is to be left. With a steady system brake pipe pressure in the brake pipe 1, the various parts of the arrangement are in the position shown and the vent valve 16 is closed against its seat 18. Similarly the vent valve 15a is also closed. This is because no signal pressure is available from either of the pressure responsive devices beneath the diaphragms of the respective vent valves. On a reduction of brake pipe pressure occurring such as is required to call for a brake application, due to the action of 21 piston 12 is displaced to the left to withdraw plunger 11. The flow of air which commences to occur in a direction from the point B to the point A, gives rise to a pressure drop across the restriction 2 which is provided in the brake pipe. When this occurs the diaphragm 9 of the pressure responsive device 3 is deflected allowing some venting of the brake pipe via conduit 5 chamber 8, orifice 10 or conduit 14 and leakage choke 29 to atmosphere and a pressure signal is applied via 10 beneath the diaphragm of the vent valve 15. This causes a deflection of the diaphragm of the vent valve 15 such as to lift the valve 16 off its seat 18 thereby effecting venting of the brake pipe via the conduits 19 and 20. In this manner, enhancement of a brake pipe reduction is effected at the point at which the apparatus is provided. This continues until a time is reached a short time afterwards when the pressure drop which occurs across the restriction 2 is insufficient to keep the orifice 10 open to sustain a signal in the conduit 14 to the vent valve and the vent valve 15 again closes. The further pressure responsive device 3a and the further vent valve 15a are provided in order that the arrangement may operate equally regardless of whether the locomotive carrying the driver's brake control valve is connected via the section of brake pipe which is adjacent the point B or the section of brake which is adjacent the point A as described above. The system is thereby entirely reversible.
In order to inhibit operation of both pressure responsive devices in response to increasing brake pipe pressure the device 21 is provided responsive to an increase of brake pipe pressure to urge the diaphragm 22 against the opening in the lower end of the tube 25. This happens for only such pressure changes because of the existence of the choke 26 in the conduit 27 which connects the brake pipe to the chamber 23. With such rise in brake pipe pressure the spring 13 is effective on the piston 12 to urge the plunger 11 against the diaphragm 9 thereby rendering the pressure responsive device 3 unresponsive to a pressure differential across the restriction 2. Similar comments also apply to the pressure responsive device 3a for increasing brake pipe pressure. This effect is the same for both the pressure responsive devices 3 and 3a regardless of from whichever of the ends B and A the increase of pressure is eminating.
Whilst not shown in the arrangement shown in the drawing, the apparatus may be provided with means, not for preventing operation of the vent valve when the brake pipe pressure is rising, but where the restriction 2 is an actual inserted restriction, for effectively removing this restriction. It may be desirable to remove the restriction for the reason that the pressure gradient along the brake pipe as a result of a pressure rise may otherwise be too great. Assuming a sufficiently rapid response to a pressure increase removal of the restriction in response thereto could inherently prevent operation of the vent valve.
Again, in an alternative arrangement it may be arranged for the restriction to be included in a control valve device by means of which the restriction is inserted only when a reducing brake pipe pressure is sensed by such means. The above mentioned consideration of the pressure gradient for a rising brake pipe pressure is thus dealt with. Further, by providing for such insertion of the restriction only during falling brake pipe conditions, it may again be found superfluous to include also the inhibition feature afforded by the spring 13, piston 12 and rod 11 of the arrangement described, for in the absence of falling brake pipe the restriction 2 will be absent and the sensing valve will not be operated.
As foreshadowed above, whilst the provision of a built-in or switched-in restriction into the brake pipe is proposed at a given point in a brake pipe, with a car of sufficient length, the fluid flow sensor may be connected to points sufficiently spaced along the brake pipe to produce a perceptible signal without an introduced additional restriction. In such an event the above alternatives whereby the restriction is introduced only by changing pressure would not of course apply.
In the event that the invention is to be applied to an arrangement for reducing the pipe gradient for an increasing brake pipe pressure along a train pipe, the valve may be a valve which operates to connect a source of air such as a reservoir or a further supply pipe to the brake pipe.
By providing for the use of the invention to be responsive to flow due to a pressure gradient existing in either direction along the train and the provision of vent valves and recharging valves the invention can be arranged to reduce the pressure gradient due either to rising brake pipe pressure or falling brake pipe pressure. Clearly in such a case such suitable means as is necessary will be included to prevent venting during recharging or recharging during venting.
It will be understood further that whilst the arrangement described as applied to a train braking system may be provided on each vehicle of a train, it may be by no means necessary to do this. By providing it at suitably much wider spaced intervals along a train, the undesired pressure gradients will readily be reduced. Accordingly, by providing sufficient such arrangements in a long train, even failure of one or more such arrangements will not substantially affect the efficiency or response time of the train braking system.
In a system where many such arrangements are included, say one per car, it may be possible to reduce the cost of each arrangement by not using the relay valves. This is because where venting or boosting occurs at each car, sufficient air may be transmitted into or out of the brake pipe via the sensing device. Thus in the above described embodiment sufficient venting for the length of pipe included in the one car may be obtained via the leak choke 29 without the relay valve 15, if the leak choke is made sufficiently large.
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A train braking system is provided which operates conventionally to effect braking by a reduction of pressure in a brake pipe and which includes on a car of the train a fluid flow sensor operating in response to a pressure gradient due to flow over a length of the brake pipe in the car or over an interposed restriction in the brake pipe, the fluid flow sensor being sensitive to such flow to operate a valve via which fluid is permitted to be applied to or removed from the brake pipe ahead of the restriction or brake pipe section having regard to the direction of propagation to tend to enhance a pressure change being caused by the flow.
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[0001] This Application is a Continuation-In-Part of prior co-pending pending application U.S. Ser. No. 09/514,089, now U.S. Pat. No. 6,196,697.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] This invention relates to airport runway light support apparatus and methods. In one aspect, this invention relates to height and azimuth adjustable container apparatus and methods for embedded container light supports for airport runways and the alignment of their light fixtures. In one aspect, this invention relates to adjustable airport runway lights and to apparatus and methods for specialized, set-in-the-ground lighting systems utilized for the purpose of guiding pilots during their approach to an airport runway and during the landing and taxi of aircraft.
[0004] 2. Background
[0005] Conventional lighting fixtures forming part of specialized, set-in-the-ground airport runway lighting systems are mounted on certain steel containers. The steel containers for these airport runway inset lights can be one-part or two-part and, sometimes, three-part containers and are set below the surface of runways, taxiways, and other aircraft ground traffic areas. The bottom sections of the containers are sometimes called shallow light bases. The top sections are called fixed-length extensions and are manufactured in different fixed lengths and diameters. Flat spacer rings are installed between the extensions and the lighting fixtures for providing further height and azimuth adjustments. These conventional steel containers, in addition to serving as bases for mounting the lighting fixtures, also serve as transformer housings and junction boxes to bring electrical power to the lighting fixtures.
[0006] In the installation of airport runway touchdown zone, centerline, and edge lighting systems, as well as in the construction or installation of taxiway centerline and edge lighting systems, and other lighting systems, these containers are embedded in the runway, taxiway, and other pavements at the time the runway and taxiway pavements are poured (concrete) or placed (bituminous). These containers, hereinafter referred to as embedded containers, vary in length and diameter. Conventional embedded containers provide an inverted flange at their top portion, which flange has a standard set of threaded holes to allow for the runway, taxiway, edge, and other light fixtures to be bolted onto them above the pavement surface, or to allow for the top section of the container to be bolted onto the bottom section, if it is a two-section container. A great majority of these existing, conventional containers are two section containers, bolted together at their inverted flanges. The light fixture then is bolted onto the top inverted flange of the top section of the two-section container. The top section of the two-section container is referred to as the fixed-length extension, which is part of the conventional embedded containers.
[0007] The top portions of the lighting fixtures are installed at a close tolerance, slightly above the pavement surface. Installations of the containers and their lighting fixtures are required on two different occasions. The first is when the runways, taxiways, and other aircraft ground traffic areas are built for the first time. The second is for resurfacing or repaving of the runways, taxiways, and other aircraft ground traffic areas. The latter is the most common, i.e., most frequent.
[0008] The light fixtures installed on the embedded containers, otherwise known as airport inset lights, have to be aligned with respect to each other in a precise, straight line on the horizontal plane known as azimuth correction, and their height has to be set within a fixed, strict tolerance measured from the pavement surface.
[0009] Each airport paving project may consist of installing hundreds or thousands of lighting fixtures and their airport inset light containers.
[0010] Runways, taxiways, and other aircraft ground traffic areas deteriorate with years of usage. This creates the need for resurfacing or repaving, i.e., replacing the asphalt of these ground surfaces. Repavement is a much more common, i.e., frequent, occurrence than the construction of new pavements.
[0011] When a runway, taxiway, or other aircraft ground traffic area is first built, or when upgrading or modernizing, or when maintenance projects require their resurfacing (repavement), the flanges on the embedded containers get buried under the pavement. This creates the need for height adjusting devices with flanges identical to those of the embedded containers to adapt the container up to the final surface and for the lighting fixtures to be installed and aligned above the payment. In many instances, this requires core-drilling the newly poured or placed pavement to reach down to the now buried top flange of the embedded container.
[0012] Depending on the lengths of the runways and taxiways, thousands of these embedded containers are affected, and a wide variety of height adjustments can be involved for each given size of embedded containers. In such an adjustment system, fixed-length extensions must be made available in many different lengths, so as to provide the many different gross height adjustments. A combination of one or more flat spacer rings, which are manufactured in thicknesses of {fraction (1/16)}, ⅛, ¼, and ½ inch (1.6, 5 3.2, 6.3, and 12.7 millimeters, approximately), and other thicknesses, can be used to provide the final height.
[0013] These fixed-length extensions have one inverted flange on each end to bolt onto the embedded container, and then flat rings are added on top of the fixed-length extension top flange before the lighting fixture is bolted onto the flange.
[0014] The fixed-length extensions and the flat spacer rings must be individually ordered to the required length. This adjustment system makes for a difficult and tedious conventional installation procedure involving (1) field measurement of each individual fixed extension length and flat spacer ring required for every container; (2) record keeping of all those field measurements and locations for ordering and verification; (3) ordering, receiving, and delivering to the field each size according to its location; and (4) frequently having to install more than one flat spacer ring to achieve the required height. The listed complications for the difficult conventional installation procedure are further magnified by the fact that the embedded containers are made in 4 different sizes: 10, 12, 15, and 16 inches (25.4, 30.5, 38.1, and 40.6 centimeters, approximately) in diameter.
[0015] These embedded containers below the pavement surface serve as light fixture bases. They also serve as transformer housings and junction boxes.
INTRODUCTION TO THE INVENTION
[0016] Depending on the location where these containers are installed, they are exposed to varying degrees and types of corrosive chemicals and materials applied to them by the aircraft and other vehicular traffic in that location. For example, runway and taxiway light fixtures, and the containers they are bolted onto, are subjected to rain water and to chemicals such as chemicals applied to the aircraft for the purpose of deicing.
[0017] It is therefore an object of the present invention to provide non-corrosive apparatus and method for mounting an airport runway light and adjusting with precision and simplicity the height and the azimuth of a runway embedded container and for aligning with efficiency, simplicity, and precision a lighting fixture installed upon the non-corrosive apparatus of the present invention.
[0018] A further object of the present invention is to provide non-corrosive apparatus and method for adjusting the height of a runway embedded container without having to install individual fixed-length extensions or flat spacer rings.
[0019] A still further object of the present invention is to provide non-corrosive apparatus and method for adjusting the height and azimuth of an array of airport runway embedded containers in a lighting system without having to install individual fixed-length extensions or flat spacer rings.
[0020] It is an object of the present invention to provide non-corrosive apparatus and method for adjusting with precision and simplicity the height and the azimuth of a container, previously installed and embedded as an airport inset light, and for aligning with efficiency, simplicity, and precision a lighting fixture installed upon the apparatus of the present invention.
[0021] It is a further object of the present invention to provide an alignment adjustments assembly that does not require the installation of a separate mud dam.
[0022] It is a further object of the present invention to provide a non-corrosive alignment adjustments assembly that does not require the installation of a separate mud dam.
[0023] A further object of the present invention is to provide non-corrosive apparatus and method for adjusting the height of a container, previously installed and embedded as an airport inset light, without having to install individual fixed-length extensions or flat spacer rings.
[0024] A still further object of the present invention is to provide non-corrosive apparatus and method for adjusting the height and azimuth of an array of containers, previously installed and embedded as airport inset lights, in a lighting system without having to install individual fixed-length extensions or flat spacer rings.
[0025] It is an object of the present invention to provide a non-corrosive alignment adjustments assembly which corrects the problem of tilting of the assembly from the vertical axis which increases the angle at which the light beam from an inset lighting fixture is projected, diverting the light beam away from incoming airplanes.
[0026] It is also another object of this invention to provide a non-corrosive alignments adjustments assembly which corrects the problem of the rotation of the assembly which alters the azimuth alignment of the lighting fixture, which in turn would impede the pilot of an incoming airplane from seeing the light.
[0027] It is yet another object of the present invention to provide a non-corrosive alignments adjustments assembly which will allow the longer, angled bottom type inset lights be installed upon it.
[0028] It is yet a further object of the present invention to provide a non-corrosive alignment adjustments assembly which does not require installing a separate flat spacer ring, with a groove on its top flat side.
[0029] These and other objects of the present invention will become apparent from a careful review of the detailed description and the figures of the drawings which follow.
SUMMARY OF THE INVENTION
[0030] Novel non-corrosive airport inset light adjustable alignment container set apparatus and method of the present invention include a light fixture and stainless steel support for airport runway, taxiway, or other aircraft ground traffic areas. A variable length means rotatably adjusts height by a vertical displacement and mounting means for mounting the airport inset light. Rotation locking means are provided for securing the rotatable adjustment apparatus from further rotation. A top flange is adapted to receive various different designs of inset lights and to provide a stainless steel protection ring “mud dam.”
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] [0031]FIG. 1 is an elevation view, partially in section, of the existing fixed-length extensions installed on an embedded container and a lighting fixture installed thereon. FIG. 1 also shows a concrete encasement and three layers of pavement.
[0032] [0032]FIG. 2 is an elevation view, partially in section, of the same existing fixed-length extensions of FIG. 1 but now shown tilted.
[0033] [0033]FIG. 3 is a pictographic view, partially in section, showing a landing passenger jet airplane, a runway, and a tilted runway centerline inset lighting fixture.
[0034] [0034]FIG. 4 is an elevation view, partially in section, of the adjustable extension component of the present invention showing a mud dam and an “O” ring with its groove.
[0035] [0035]FIG. 5 is an elevation view, partially in section, showing an Allen-set screw component of the present invention.
[0036] [0036]FIG. 6 is an elevation view, partially in section, of the adapter flange component of the present invention.
[0037] [0037]FIG. 7 is an elevation view, partially in section, of an airport inset lighting fixture, showing a straight bottom.
[0038] [0038]FIG. 8 is an elevation view, partially in section, of an airport inset lighting fixture, showing an angled bottom.
[0039] [0039]FIG. 9 is a plan view of the lighting fixture of FIG. 7 and of FIG. 8.
[0040] [0040]FIG. 10 is an elevation view, partially in section, of a mud dam protection ring.
[0041] [0041]FIG. 11 is an elevation view, partially in section, of the alignments adjustments assembly of the present invention shown installed on an existing embedded container. FIG. 11 also shows an airport inset lighting fixture mounted on the adjustments assembly.
[0042] [0042]FIG. 12 is a plan view of the top flange of the embedded container of FIGS. 1, 2, and 11 .
[0043] [0043]FIG. 13 is an elevation view, partially in section, of the universal top adjustment container of the present invention and shows an airport inset lighting fixture and an “O” ring.
[0044] [0044]FIG. 14 is a plan view, i.e., a top view, of the universal top adjustment container of the present invention as shown in FIG. 13 without the lighting fixture.
DETAILED DESCRIPTION
[0045] The present invention provides a height and azimuth adjustable container set, utilized for all the purposes embedded containers are utilized, i.e., to serve as bases for lighting fixtures, as transformer housings, and as junction boxes, but with a major difference from conventional embedded containers. The adjustable container sets of the present invention also are utilized for the precise and simplified, economic mounting and adjusting of the height of the lighting fixture to be mounted upon it. Also, the adjustable containers of the present invention provide for precise and simplified, economic aligning of the azimuth of the lighting fixtures and aligning the lights with respect to each other, by virtue of the azimuth alignment.
[0046] The adjustable container set of the present invention is used to improve existing containers, while being efficiently and economically adjustable. These containers are installed in airport runways, taxiways, and other aircraft ground traffic areas to serve as bases for lighting fixtures, transformer housings, and junction boxes. The adjustments take place when the containers and their lighting fixtures are installed initially, e.g., when new runway, taxiway, and other aircraft ground traffic areas are first built and every time they are repaved.
[0047] The present invention provides a height and azimuth alignments adjustments assembly utilized for the more economic, precise, and simplified adjusting of the heights of concrete embedded containers and the azimuth alignment of airport inset lighting fixtures mounted thereon. These containers of the present invention are installed and reused in airport runways and taxiways and other aircraft ground traffic areas to serve as bases for lighting fixtures, transformer housings, and as junction boxes.
[0048] In the actual testings and installations of the alignments adjustments assembly disclosed and described in U.S. patent application Ser. No. 08/002,014 filed Jan. 8, 1993 and entitled “Alignments Adjustments Assembly Apparatus and Method,” now U.S. Pat. No. 5,541,362, I have discovered certain aspects which could be modified.
[0049] One drawback is that airport runway light bolts used to install the airport runway light on or in the airport runway light support can be part of a corrosion problem. Corrosive materials such as deicing chemicals used on the aircraft can accelerate corrosive problems between the light bolts and the light support. The airport runway light stainless steel bolts can accelerate corrosive attack by a galvanic action between dissimilar metals.
[0050] The present invention provides an alignment adjustments assembly which corrects the problem of corrosion.
[0051] One drawback is that a great number of the existing conventional, fixed-length extensions installed as stacked-on embedded containers have tilted from their vertical axis. This tilting, which at the place of tilting is relatively small, nevertheless increases the angle at which the light beam from an inset lighting fixture is projected, thereby diverting the light beam away from incoming airplanes. At one-half mile (1 kilometer) away from the approach area, it is difficult for the pilot of a landing airplane to see the light because of the very large divergence at that point from the point at which it should otherwise be, when properly height-adjusted.
[0052] The present invention provides an alignment adjustments assembly which corrects the problem of tilting.
[0053] Another drawback encountered is that the new larger and heavier airplanes, now becoming more common, exert a larger torsional force upon the inset lighting fixtures. Tests made to simulate those larger torsional forces on the alignment adjustment assembly disclosed and described in U.S. patent application Ser. No. filed Jan. 8, 1993 and entitled “Alignments Adjustments Assembly Apparatus and Method,” now U.S. Pat. No. 5,541,362, proved that a very slight rotational movement occurs, even though considered relatively insignificant today. Nevertheless, even heavier airplanes could provide a more significant rotational movement that would alter the azimuth alignment of the lighting fixture, which in turn would impede the pilot of an incoming airplane from seeing the light.
[0054] The present invention provides an alignments adjustments assembly which corrects the problem of the rotation of the assembly.
[0055] Yet another drawback encountered is the need to install a separate component called the mud dam, consisting of a flat, three-quarters inch (19 mm) thick spacer ring with a flat, thin steel band welded all around the periphery of the flat spacer ring. This band is about one and a quarter inches (3.3 cm) wide.
[0056] The present invention provides an alignment adjustments assembly that does not require the installation of a separate mud dam.
[0057] A further drawback encountered is that there are two types of inset light construction with respect to its bottom side. The bottom on one type is short and flat. The bottom on the other is longer and at an angle with respect to the light base vertical axis. The longer, angled bottom does not allow the light to fit properly on the top flange of the apparatus as disclosed and described in U.S. patent application Ser. No. 08/002,014 filed Jan. 8, 1993 and entitled “Alignments Adjustments Assembly Apparatus and Method,” now U.S. Pat. No. 5,541,362.
[0058] The present invention provides an alignments adjustments assembly which will allow the longer, angled bottom type inset lights to be installed upon it.
[0059] Yet a further drawback encountered is that, in a great many occasions, an “O” ring seal is specified. In such cases, a separate flat, three-quarters inch (19 mm) thick spacer ring, with a groove on its top flat side, is installed between the fixed-length extension and the lighting fixture.
[0060] The present invention provides an alignment adjustments assembly which does not require installing a separate flat spacer ring with a groove on its top flat side.
[0061] The invention includes an existing embedded container with an inverted flange on one end onto which an adapter flange bolts. The adapter flange has Acme threads in its center aperture. The apparatus and method of the present invention also include an outside Acme threaded adjustable extension, which threads down into the adapter flange, to provide the precise height required and the precise alignment of its lighting fixture. The adjustable height extension has a top flange to provide a base upon which the specified lighting fixture can be bolted.
[0062] The present invention provides height and azimuth light support sets utilized for the more efficient and economic, precise, and simplified adjusting of the heights of exiting art embedded containers and the alignment of their light fixtures. These containers are installed in airport runways and taxiways to serve as bases for lighting fixtures, as transformer housings, and as junction boxes.
[0063] Referring now to FIGS. 1 and 2, a container 1 is represented schematically with three fixed-length extensions 2 , 7 , and 11 bolted together. Container 1 is embedded in concrete 25 at the time an airport runway, taxiway, and other aircraft ground traffic areas (hereinafter aircraft ground traffic areas) are first built. These ground traffic areas generally are built upon a compacted granular sub-base 26 .
[0064] Steel containers 1 , in addition to serving as bases for mounting airport inset lighting fixtures 95 also serve as transformer housings and junction boxes to bring electrical power to lighting fixture 95 , as shown in FIGS. 1, 2, and 7 . Fixed-length extension 2 is bolted to top flange 30 on container 1 , which has 12 threaded bolt holes 136 , as shown in FIG. 12, by means of its bottom flange 4 and bolts 3 . Fixed-length extension 2 is bolted to bottom flange 6 of fixed-length extension 7 by means of its top flange 5 and bolts 8 . Fixed-length extension 7 is bolted on top of fixed-length extension 2 .
[0065] Fixed-length extensions have twelve bolt holes in both of their flanges, i.e., top flange 5 and bottom flange 4 of extension 2 , as shown in FIG. 1. The bolt holes, not shown, on the top flanges of the extensions are threaded, while the bolt holes, not shown, on the bottom flange are not threaded. Nevertheless, the bolt holes in both flanges of the fixed-length extensions are on a bolt hole circle diameter identical to bolt circle diameter 137 , as shown in FIG. 12, of container 1 .
[0066] Fixed-length extension 7 is bolted to bottom flange 10 of fixed-length extension 11 by means of its top flange 9 and bolts 12 . Fixed-length extension 11 is bolted on top of fixed-length extension 7 .
[0067] Fixed-length extensions provide only a gross height adjustment. One or a plurality of flat spacer rings 15 are required for providing the more precise final height adjustment.
[0068] Flat spacer rings 15 are installed on top flange 13 of fixed-length extension 11 , as shown in FIG. 1, i.e., the top fixed-length extension, to provide the final height adjustment 17 for inset lighting fixture 95 . Flat spacer rings 15 can be one or more. They are fabricated as thin as {fraction (1/16)} inch (1.6 mm) and as thick as three-quarters inch (19 mm) or thicker. Mud dam 36 , as shown in FIGS. 1 and 10, comes next on top of spacer rings 15 . The inset lighting fixture 95 is bolted together with flat spacer rings 15 and mud dam 36 onto the top flange 13 of the top fixed-length extension 11 by means of bolts 14 .
[0069] Continuing to refer to FIGS. 1 and 2, several layers of pavement 19 , 20 , 21 are shown, to exemplify the fact that fixed-length extensions 2 , 7 , and 11 are utilized for height adjustments every time an aircraft ground traffic area is first built or upgraded by the installation of new pavement, i.e., each new layer of pavement 19 , 20 , and 21 . The new layers create new surfaces 22 , 23 , and 24 and therefore new heights.
[0070] These airport aircraft ground traffic area upgrades create the need for heights adjusting devices, with flanges identical to those of the embedded container 1 , in order to adapt the container 1 to the new surface, i.e., the new height and further in order for the lighting fixture 95 to be installed slightly above the new pavement surface, i.e., surface 22 , 23 , or 24 , at a close tolerance 17 above new pavement surface 24 , for example.
[0071] In order to seal pavement layers 19 , 20 , 21 around container 1 , grout 18 is utilized. Pavement rings 36 , commonly known in the industry as mud dam 36 , as shown in FIGS. 1 and 10, are installed on top of spacer rings 15 to protect lighting fixture 95 from being splashed by the grout 18 at the time of its application.
[0072] Inset lighting fixture 95 is set inside mud dam protection ring 36 , as shown in FIG. 10. Mud dam 36 consists of a flat ring 38 , as shown in FIG. 10, generally of ¾ inch (19 mm) in thickness, with a 1 to 1¼ inch (2.54 to 3.27 cm) wide, flat, thin steel band welded around the periphery of flat ring 38 . Flat ring 38 has bolt holes 39 which match bolt holes, not shown, on flat spacer rings 15 , on fixed-length extension 11 as well as on lighting fixture 95 . Bolt holes on fixed-length extension 11 are threaded. Lighting fixture 95 is bolted onto fixed-length extension 11 , together with mud dam 36 and flat spacer rings 15 by means of bolts 14 . Mud dams 36 are generally provided with grooves 43 in order to accept “O”-ring gasket 44 .
[0073] When any one layer of pavement is first placed, it is done by placing it over the entire surface, i.e., surface 31 . Then the pavement 19 is core-drilled at the location of each container 1 to remove the pavement at that location to install fixed-length extension 2 , any flat spacer ring 15 , mud dam 36 , and finally lighting fixture 95 at the new height created by pavement 19 and surface 22 , by way of example. This process is repeated every time a new layer of pavement is added, i.e., for further layers 20 and 21 . The core drilled hole is larger in diameter than the diameter of container 1 , hence the requirement to utilize grout 18 to fill in the void and therefore the need to install a mud dam 36 , as shown in FIG. 10, to protect lighting fixture 95 , as shown in FIGS. 1, 2 when grout 18 is poured.
[0074] A new method has been used for a few years already, whenever an aircraft ground traffic area reconstruction takes place, i.e., resurfacing or repaving. Instead of adding a new layer of pavement on top of the last one installed, the last one layer, i.e., pavement layer 21 , is milled down by large roto-milling machines. This method is extensively explained in my U.S. Pat. No. 5,431,510 entitled “Overlay Protection Plate Apparatus and Method.”
[0075] Prior to roto-milling the pavement top layer, i.e., layer 21 , the lighting fixtures, any spacer rings, the mud ring, and the top, existing fixed-length extensions have to be removed. An overlay protection plate, not shown, is bolted to top flange 30 , on container 1 , to prevent debris from falling into container 1 . After roto-milling, a new layer of pavement is installed, and the new pavement is core-drilled at the location of each container 1 to replace the items removed back to their original position. Core drilling at each embedded container location is done to provide access for reinstalling the items previously removed. Nevertheless, in a great percentage of the cases, i.e., at each of the individual container locations, differences of height occur, creating the need for the installation of additional flat spacer rings 15 on top of the ones removed and being reinstalled.
[0076] Referring to FIGS. 1 and 2, lighting fixture 95 is installed at a close tolerance 17 slightly above pavement surface 24 . The optical system, not shown, inside the lighting fixture, projects its light beam 32 through lens 107 in window 108 of lighting fixture 95 at a precise angle 34 from surface 24 to allow a pilot landing aircraft 51 , as shown in FIG. 3, see light beam 32 , from a distance of about one-half mile (1 kilometer), when landing at night or under other low visibility conditions. Lighting fixtures 95 are also known as centerline lights because they are installed on the embedded containers in the center of the aircraft ground traffic areas, i.e., runways, taxiways, and others.
[0077] The continuous landing of aircraft, day and night, year after year, on top of these lighting fixtures can provide a slight tilting 41 , as shown in FIG. 2, of the lighting fixture and fixed-length extension 11 , as represented by 41 (not to scale), as shown in FIG. 2, for the purpose of making this explanation more clearly understood. This tilting 41 will alter the installed height tolerance 17 , as shown in FIG. 1, which now would be larger as represented by 42 in FIG. 2. The maximum installed height tolerance 17 is {fraction (1/16)} inch (1.6 mm), per F.A.A. (U.S. Federal Aviation Administration) specifications. Tilting 41 is shown as a separation of flange 10 of fixed-length extension 11 from flange 9 of fixed-length extension 7 .
[0078] Even the slightest tilting of lighting fixture 95 and the associated extension produces an angular deviation, angle 35 , as shown in FIGS. 2 and 3, which is larger than the precise angle 34 obtained by a combination of the precise height adjustment of lighting fixture 95 and the angle at which light beam 32 is emitted from lighting fixture 95 , through its lenses 107 , in windows 108 , as shown in FIGS. 1 and 2. This lighting fixture emitted light beam angle is set at the factory and is precisely established by F.A.A. regulations.
[0079] An increased angle 35 would project emitted light beam 33 away from a line of sight from the pilot when landing aircraft 51 , as shown in FIG. 3, as it descends for landing. As a result, the pilot of aircraft 51 would not be able to see light beam 33 when landing at night or during poor visibility conditions. An increase in the height adjustment 17 of lighting fixture 95 would have the same effect, i.e., the light beam would not be visible to the pilot at landing. In addition, an increased installed height creates the danger of the lighting fixture being plowed-off, during winter time, when snow is regularly plowed off airport ground traffic areas. This creates the danger of lighting fixtures, bolts, rings, and other components, being thrown onto these traffic areas, with the resulting danger to landing aircraft.
[0080] Conventionally, tilting is field-corrected by installing a thick tapered spacer ring, not shown. These tapered rings are custom made, per field measurement, and they are installed after first removing some of the existing flat spacer rings 15 , to correct angular deviation 35 of light beam 33 to the correct angular adjustment 34 of the light beam. Tilting of the fixed-length extension is corrected, when the apparatus and methods of the present invention are utilized, because fixed-length extensions, bolted one on top of the other are no longer required.
[0081] Referring to FIGS. 7, 8, and 9 , lighting fixtures today are manufactured with two different types of bottom portions. FIG. 7 shows lighting fixture 95 with six non-threaded, counter sunk bolt holes 109 drilled through mounting flange 106 . Bolt holes 109 are set apart at an angle 115 of 60 degrees one from another, in bolt circle 114 . Lighting fixture 95 is provided with optical lenses 107 in countersunk windows 108 and with a flat, short, straight down bottom portion 100 . Electrical wires 111 and connector 112 are provided for bringing electrical power to lighting fixture 95 from an isolation transformer, not shown, in conventional container 1 , as shown in FIGS. 1 and 2.
[0082] Lighting fixture 105 of FIG. 8 has six non-threaded, countersunk bolt holes 109 drilled through mounting flange 106 . Bolt holes 109 are set apart at an angle 115 of 60 degrees one from another, in bolt circle 114 . Lighting fixture 105 is provided with optical lenses 107 in countersunk windows 108 and with a long, angled bottom 110 , hence the novel angled 66 opening 67 of adjustable extension 55 , as shown in FIG. 4. Angled 66 opening 67 allows lighting fixture 105 to be installed on flange 62 of the extension, in addition to allowing also the installation of lighting fixture 95 , as shown in FIG. 7.
[0083] Continuing to refer to FIG. 8, lighting fixture 105 is also provided with wires 111 and connector 112 for bringing electrical power to lighting fixture 105 from conventional embedded container 1 , as shown in FIGS. 1 and 2.
[0084] Azimuth orientation arrows 113 are engraved on mounting flange 106 in the countersunk windows 108 area. Arrows 113 are also engraved in countersunk windows 108 of lighting fixture 95 . The difference between lighting fixture 95 and lighting fixture 105 is in the short, flat bottom portion 100 of fixture 95 versus the longer, angled bottom portion of fixture 105 .
[0085] Engraved azimuth arrows 113 are required for aiding a lighting fixture installer in orienting lenses 107 , on windows 108 , directly to the exact azimuth alignment, to correctly align, in azimuth, the light beam projected through lenses 107 with the aircraft landing direction. The azimuth alignments are required when the lighting fixture is first installed and on every occasion maintenance is performed on the fixture, i.e., removal for bulb change and others.
[0086] [0086]FIG. 9 is a top view, i.e., a plan view, of the lighting fixtures of FIGS. 7 and 8. The lighting fixtures 95 , 105 have six countersunk bolt holes 109 each on bolt circle 114 , with a bolt circle diameter identical to the diameter of the bolt circle, not shown, of bolt holes 64 , on top flange 62 , as shown in FIG. 4.
[0087] The bolt circle diameter, the number and size of bolts and bolt holes in the lighting fixtures, as well as in the flange where the lighting fixtures are to be installed, i.e., top flange 62 , as shown in FIG. 4, or in conventional top flange 13 , as shown in FIG. 1, are specified by specifications known as Circulars, issued by the F.A.A.
[0088] Referring now to FIGS. 4, 5, and 6 , adjustable extension 55 and adapter flange 85 represent the preferred embodiment of the alignments adjustments assembly of the present invention.
[0089] Adjustable extension 55 consists of a tubular, cylindrical section, defined by a non-threaded top portion 58 which has its bottom portion 57 threaded with Acme threads 56 , e.g., by way of example at four threads per inch (2.54 cm). Top portion 58 and bottom threaded portion 57 are the wall of the cylindrical portion, i.e., the wall of a tubular cylinder, shown in elevation, partially in section, in FIG. 4.
[0090] Acme threaded portion 57 is threaded for approximately six inches (15 cm) from bottom end 61 . Threaded portion 57 has a minimum of six vertical rows of threaded holes 59 , 60 , i.e., parallel to its vertical axis 68 , as opposed to three vertical rows of holes at 120 degrees apart, disclosed in U.S. patent application Ser. No. 08/002,014 filed Jan. 8, 1993 entitled “Alignments Adjustments Assembly Apparatus and Method,” now U.S. Pat. No. 5,541,362. Holes 59 are on a horizontal plane different from holes 60 , i.e., intercalated, i.e., staggered as shown in FIG. 4, so that at all times there will be a minimum of four and a maximum of six holes 59 , 60 for threading Allen set-screws 81 , as shown in FIG. 5, through them and for tightening against inside threaded surface 87 of adapter flange 85 , as shown in FIG. 6. By the method of the present invention, at least one Allen set-screw 81 , as shown in FIG. 5, protruding through holes 59 or 60 , penetrates at least one eighth inch (3.2 mm) into a drilled aperture 86 , as shown in FIG. 6, on inside threaded surface 87 of adapter flange 85 .
[0091] Allen set-screws are threaded through both holes 59 and 60 , shown threaded through hole 59 on FIG. 5 for simplification purposes. Allen set-screws are of a minimum ½ inch (1.3 cm) nominal diameter.
[0092] Top flange 62 is welded at top portion 71 of the tubular, cylindrical portion of the extension 55 . Top flange 62 has 12 threaded bolt holes 64 through it, when seeing it in plan, but shown only in section in FIG. 4. These threaded bolt holes 64 have a bolt circle diameter, not shown, that coincides with bolt circle diameter 114 , as shown in FIG. 9, of lighting fixture 95 and 105 , as shown in FIGS. 7 and 9, respectively. The bolt circle and bolt size are mandated by the F.A.A. specifications, i.e., U.S. Federal Aviation Administration specifications. All features shown on FIG. 9, a plan view, coincide with a plan view, not shown, of FIG. 7 in all respects, i.e., they are substantially identical. Therefore, either lighting fixtures of FIG. 7 or FIG. 8 can be bolted onto top flange 62 .
[0093] Top flange 62 has opening 67 at an angle 66 of approximately 45 degrees. In addition to accepting lighting fixture 95 , as shown in FIG. 7, it also accepts lighting fixture 105 , as shown in FIG. 9.
[0094] Preferably top flange 62 and tubular cylindrical portion 57 are made of stainless steel. The stainless steel assembly 55 of the present invention provides an alignment adjustments assembly which corrects the problem of corrosion from materials such as corrosive deicing chemicals or by a galvanic action between dissimilar metals between the light bolts and the light support.
[0095] Novel mud dam protecting ring 69 , consisting of a 1 to 1¼ inches wide (2.54 to 3.27 cm), thin, stainless steel band, is built in one piece with top flange 62 , if adjustable extension 55 is built in one piece, which is the preferred method. Mud dam protecting ring 69 can also be welded all around the outer periphery of top flange 62 if adjustable extension 55 is built of individual components. Mud dam 69 is positioned to protect the lighting fixture and its lenses 107 , as shown in FIGS. 7, 8, and 9 from grout 122 , as shown in FIG. 11, when grout 122 is poured. Groove 65 is provided on surface 63 of top flange 62 in order to accept “O”-ring 70 , shown lifted from groove 65 , on FIG. 4.
[0096] The adjustable extension of the present invention can be cast, in one piece, e.g., from stainless steel, comprising the tubular, cylindrical portion as well as the top flange 62 and mud dam protection ring 69 . It can then be machine-finished including groove 65 and mud dam protection ring 69 . Acme-threads 56 are cut for a minimum of up to 6 inches (15 cm) or more from bottom end 61 . All holes 59 , 60 , and 64 are then drilled and tapped. Preferably, each individual component is made of stainless steel.
[0097] The adjustable extension can also be made of individual components, i.e., a tubular piece, to obtain the cylindrical portion and a standard steel plate, machine-finished to obtain the top flange 62 , to which a thin, steel band is welded to make the protection ring 69 . Then the flange 62 is welded at 71 , top end of non-threaded portion 58 of the tubular piece, i.e., the cylindrical portion. Any additional machine-finishing then is done, including groove 65 . Acme threads 56 are cut for a minimum of 6 inches (15 cm) or more from bottom end 61 . All holes 59 , 60 , and 64 are then drilled and tapped.
[0098] Optionally, Acme threads 56 could be cut, and holes 59 and 60 drilled and tapped in the field at the point of use.
[0099] The order in which the fabrication steps are herein described, i.e., for casting in one piece or for individual components, is not intended to limit the many variations of manufacturing sequencing, as those skilled in the art would recognize. Therefore, all sequencing steps, whether listed or not, are part of the apparatus and method of the present invention.
[0100] As it can be readily understood by those skilled in the art, the adjustable extension can be made in any overall length, including any length of its threaded portion 57 . This feature provides the design engineers a great advantage in planning for future aircraft ground traffic changes, i.e., additional layers of pavement or the replacement of existing layers of pavement with new, thicker layers, to upgrade these aircraft traffic areas to new generations of larger, heavier aircraft.
[0101] [0101]FIG. 5 represents the Allen set-screw 81 component of the present invention shown threaded-in and protruding through threaded portion 57 of the adjustable extension.
[0102] [0102]FIG. 6 represents the circular adapter flange 85 component part of the present invention shown in elevation. Non-threaded aperture 86 is at least ⅛ inch (3.2 mm) deep, drilled into Acme threaded surface 87 in opening 88 . Inside opening 88 is threaded with 4 Acme threads per inch (2.54 cm) in order to thread extension 55 into it. Non-threaded holes 89 are 12 in number (only two shown) and are drilled through surface 90 . Bolt holes 89 are drilled on a bolt circle, not shown, identical to the bolt circle 137 , as shown in FIG. 12, on top flange 30 of conventional embedded container 1 , as shown in FIGS. 1 and 2. Adapter flange 85 thereby provides the means for the installation of adjustable extension 55 onto embedded stainless steel container 1 A, as shown in FIGS. 11 and 12.
[0103] For the installation of the alignments adjustments assembly of the present invention on airport runway embedded stainless steel container 1 A, adapter flange 85 is bolted onto top flange 30 , as shown in FIGS. 1, 2, and 12 of embedded container 1 after removing bolts 3 , as shown in FIGS. 1 and 2 and all fixed-length extensions 2 , 7 , and 11 . When adapter flange 85 is bolted onto stainless steel container 1 A, the adjustable extension 55 can be threaded into adapter flange 85 , through Acme threaded opening 88 , in order to install an airport inset lighting fixture upon top flange 62 , as shown in FIGS. 4 and 11, of adjustable extension 55 .
[0104] All Allen set screws are threaded through holes 59 , 60 of extension 55 and torqued to a minimum of 60 foot-pounds (8 kilogram-meters) against Acme threaded surface 87 of adapter flange 85 , one of them, torqued against the inside of drilled aperture 86 .
[0105] Referring now to FIG. 11, a completed installation of the apparatus of the present invention is represented. Aperture 86 on Acme threaded surface 87 is drilled as follows. First, adjustable extension 55 with “O” ring 70 , in groove 65 and with lighting fixture 105 bolted onto it, as shown in FIG. 11, is threaded into adapter flange 85 , which has been bolted already onto stainless steel container 1 A by means of bolts 121 . Lighting fixture 105 on adjustable extension 55 then is brought to the exact height and azimuth by threading in adjustable extension 55 until azimuth orientation arrows 113 are aligned to the precise azimuth at the required height. Prior to any installation, a surveyor provides the necessary centerline marks 138 , as shown in FIG. 12, on the pavement, i.e., of a runway, for aiding the installer in finding the correct azimuth line. At this point, the lighting fixture is removed, and all required Allen setscrews are installed through holes 59 , 60 of adjustable extension 55 and fully torqued at 60 foot-pounds (8 kilogram-meters) against Acme threaded surface 87 to immobilize adjustable extension 55 in place, keeping it at the desired azimuth alignment and height adjustment. Then, aperture 86 is drilled approximately ⅛ inch (3.2 mm) into surface 87 of adapter flange 85 , through one of threaded holes 59 or 60 of the adjustable extension 55 . Immediately after aperture 86 is drilled-in, the remaining Allen set-screw 81 is threaded through the respective hole 59 or 60 and fully torqued at 60 foot-pounds (8 kilogram-meters) against the inside of aperture 86 . By making at least one Allen set-screw 81 penetrate at least ⅛ inch (3.2 mm) into aperture 86 , on surface 87 of adapter flange 85 , by installing six Allen set-screws, and by making the set-screw ½ inch (12.7 mm) in diameter, the adjustable extension 55 and the lighting fixture mounted thereupon will not be made to turn by the torque tangentially applied by the force of airplane wheels, including those of the newer, heavier airplanes landing upon the lighting fixtures or by the twisting action created by heavy aircraft locked wheels when turning. All holes 59 , 60 not utilized are plugged-in with threaded, plastic plugs, not shown. When holes 59 , 60 are plugged-in, the lighting fixture is connected to electrical power connector 123 from imbedded container 1 by means of cable 111 and connector 112 . Then the lighting fixture is re-bolted onto top flange 62 of adjustable extension 55 with its azimuth orientation arrows 113 aligned in azimuth, by means of bolts 120 . “O” ring 70 is compressed by the bolting pressure, thereby providing a tight water seal. Angled bottom 110 of lighting fixture 105 fits very well in angled 66 opening 67 , as shown in FIG. 4, of the adjustable extension.
[0106] At this point, the installation is completed by pouring-in grout 122 all around the alignments adjustments assembly 55 , 85 , of the present invention. It can be seen that the novel protection ring 69 , as shown in FIGS. 4 and 11, prevents grout 122 from getting on the lighting fixture, especially so on its lens 107 through window 108 . It is also readily understood that groove 65 , as shown in FIG. 4, provided on surface 63 of top flange 62 of adjustable extension 55 eliminates the requirement for installing a separate spacer ring with a groove on it for the installation of “O” ring 70 .
[0107] The alignments adjustments assembly of the present invention is reusable. When the alignments adjustments assembly is installed and the airport aircraft ground traffic area is modified, creating a higher or lower surface, i.e., if surface 24 were made higher or lower, extension 55 can be threaded in or out, after first removing all Allen set-screws 81 , to provide a new height adjustment without affecting the azimuth alignment. Azimuth is a straight line, i.e., toward the horizon, in the direction of aircraft landings, with the centerline 138 , as shown in FIG. 12, of the aircraft ground traffic area runway, taxiway, defining this straight line. Thus the embedded containers with their inset lights mounted thereupon all are installed at a specified distance one from another on this centerline for the length of the aircraft ground traffic area.
[0108] At the time embedded stainless steel container 1 A is first installed, its top flange 30 , as shown in FIG. 12, is aligned in azimuth, by aligning centerline 138 of the aircraft ground traffic area to pass exactly aligned with two diametrically opposed threaded bolt holes 136 . Prior to its installation, a surveyor provides markings on the pavement for aiding in the azimuth alignment of stainless steel container 1 A. Bolt holes 136 are at an angle 135 of 30 degrees apart, and they are set on bolt circle 137 with a diameter identical to bolt circle 114 , as shown in FIG. 9, on the lighting fixtures 95 , 105 . Bolt circle diameter 137 on top flange 30 also is identical to the bolt circle diameter, not shown, on adapter flange 85 , which bolts thereupon, by the method of the present invention.
[0109] Adjusting the height of adjustable extension 55 would not affect the azimuth alignment of a lighting fixture installed upon its flange 62 , as shown in FIG. 11, because extension 55 Acme threaded portion 57 is provided with at least four Acme threads 56 per inch (2.54 cm). At four Acme threads per inch (2.54 cm), it would take four full, 360 degree turns of adjustable extension 55 , for it to go up or down one inch (2.54 cm). Therefore the adjustable extension will move up or down only ¼ inch (6.3 mm) when rotated 360 degrees about its axis 68 , i.e., one single, complete rotation. A 30 degree turn of adjustable extension 55 will produce a height change of only 0.0208 inches (0.05 mm), up or down, i.e., one twelfth of ¼ inch (6.3 mm). The measure of 0.0208 inches (0.05 mm) is slightly more than {fraction (1/64)} inch (1.6 mm) The overall tolerance 17 , as shown in FIG. 1 is {fraction (1/16)} inch (1.6 mm). A 30 degree turn equals one twelfth of one full 360 degree rotation. Therefore, adjustable extension 55 can be rotated a few degrees about its axis 68 in any direction to obtain a very precise azimuth alignment without negatively affecting its height adjustment. Any azimuth alignment adjustment would always be 15 degrees or less because bolt holes 109 , as shown in FIG. 9, of the lighting fixtures, by FAA mandate, are spaced apart 60 degrees, i.e., only six holes. Bolt holes 64 on top flange 62 , as shown in FIG. 4, are spaced at 30 degrees, exactly the same as bolt holes 136 , as shown in FIG. 12, on top flange 30 of the embedded container, i.e., 12 bolt holes, also by FAA specifications. The diameter of bolt circles 114 , as shown in FIG. 9, and 137 , as shown in FIG. 12, are also identical to that of the top flange 62 . Accordingly, a 30 degree azimuth alignment adjustment is obtained by properly positioning the lighting fixture upon top flange 62 of adjustable extension 55 , matching its bolt holes 109 with the two bolt holes 64 on flange 62 , positioning arrows 113 closest to the correct azimuth alignment marked on the pavement by a surveyor. The final, precise adjustment of 15 degrees or less is done by simply turning the adjustable extension. From FIG. 9, it can be seen that windows 108 are centered between two bolts 109 , and, therefore, orientation arrow 113 is at 30 degrees apart from the two adjacent bolt holes 109 .
[0110] Referring now to FIGS. 13 and 14, a universal top adjustable alignment container 255 is shown in elevation in FIG. 13 and in plan view, i.e. top view, in FIG. 14. The non-corrosive top adjustable alignment container 255 is another preferred embodiment of the present invention.
[0111] [0111]FIG. 13 shows, for the purpose of illustration, an airport inset light 205 , a new type of airport inset lighting fixture, manufactured by Hughes Phillips. The novel features of the universal top adjustable alignment container 255 allow the installation of any of the three types of lighting fixtures that exist in the U.S. market today, e.g., lighting fixture 95 , shown in elevation in FIG. 7 and in plan view in FIG. 9; lighting fixture 105 , shown in elevation in FIG. 8 and in plan view in FIG. 9; and the newest inset lighting fixture 205 , shown in elevation in FIG. 13.
[0112] Any of the three lighting fixtures 95 , 105 , and 205 can be installed on the universal top adjustable alignment container 255 without requiring its top flange 262 to have an angled opening 66 (FIG. 4), as it is required for the flange 62 of the adjustable extension 55 of FIG. 4.
[0113] Continuing to refer to FIG. 13, the novel top flange 262 of the universal top adjustable alignment container 255 has an opening 267 with a straight inside surface 266 instead of an angled inside surface 66 as shown in FIG. 4. In addition, the top flange 262 is thicker than the top flange 62 of FIG. 4. This additional thickness allows a stepped bottom 201 of the lighting fixture 205 to be perfectly fit inside the opening 267 of the top flange 262 , with a flange 206 inside the mud dam 269 .
[0114] The universal top adjustable alignment container 255 of FIG. 13 is preferably cast in one piece, in stainless steel. The casting can then be machined to form the top flange 262 , a flat surface 263 , with a groove 265 in it, the mud dam 269 , and an opening 267 , with its straight surface 266 . Twelve threaded holes 264 (only two shown) are drilled and tapped through the surface 263 of the flange 262 . Then acme threads 256 are cut, at four threads per inch, on a surface 257 for a minimum of six inches from a bottom a 261 of a tubular section 257 . The tubular section 257 is of a required wall thickness 274 to allow for the required strength of the threads to resist shearing forces created by the axial loading forces applied upon the lighting fixtures by landing aircrafts. At this point, holes 259 and 260 are drilled and tapped through the tubular section 257 , through its wall thickness 274 .
[0115] Holes 259 and 260 are intercalated, i.e., staggered. These holes 259 and 260 , if required, could be drilled and tapped in the field instead of in the factory. Nevertheless, drilling and tapping holes 259 and 260 in the field is not the preferred method because it is not cost effective, and it is inefficient.
[0116] Threaded bolt holes 264 of the top flange 262 are a total of twelve, i.e., at 30 degrees 235 from each other, as shown on FIG. 14. These holes 264 are drilled and tapped through a surface 263 of the flange 262 on a bolt circle 214 (FIG. 14), which is similar to the bolt circle 114 of FIG. 9, on the lighting fixtures 95 and 105 of FIGS. 7 and 8, respectively.
[0117] Bolt holes 209 of lighting fixture 205 are drilled through flange 206 on a bolt circle (not shown) similar to bolt circle 214 on top flange 262 . Lighting fixture 205 has six bolt holes (only two shown) spread at sixty degrees apart, similar to the configuration 235 shown of FIG. 9 for lighting fixtures 95 , 105 . The number of holes, sizes, and degrees apart are all mandated by the FAA, i.e., the Federal Aviation Administration, in specifications known as FAA Circulars.
[0118] Lighting fixture 205 of FIG. 13 has a stepped bottom comprising a portion 201 and a portion 200 . The portion 200 provides electrical wires 211 that bring electrical power to the lighting fixture 205 . Flange 206 is utilized to install the lighting fixture upon surface 263 of top flange 262 of universal top adjustable container 255 , inside its mud dam 269 . Lighting fixture 205 , when bolted onto top flange 262 , compresses an “O” ring 270 in a groove 265 , providing a water tight seal between the lighting fixture 205 and the inside of the universal top adjustable alignment container 255 of FIG. 13.
[0119] Lighting fixture 209 has two countersunk windows 208 , similar to the countersunk windows 108 on lighting fixtures 95 , 105 of FIG. 9. The lighting fixture 205 also has one azimuth orientation arrow (not shown) engraved in each of countersunk windows 208 . The countersunk windows 208 , engraved azimuth arrows, lighting system, and their angular positioning for all lighting fixtures manufactured in the U.S. are all very similar and they are all mandated by FAA regulations, i.e., FAA Circulars.
[0120] Engraved azimuth arrows (not shown) on the lighting fixture 205 are utilized to aid the installer in aligning the lighting fixture 205 in azimuth, on the runway centerline and in the direction 32 of landing aircraft 51 (FIG. 3).
[0121] Referring now to FIG. 14, a plan view, i.e., a top view, of the universal top adjustable alignment container 255 , of FIG. 13, is shown. FIG. 14 shows the top flange 262 , with its mud dam 269 and twelve threaded holds 264 drilled and tapped on the bolt circle 214 , at thirty degrees 235 from each other. FIG. 14 also shows groove 265 in surface 263 of top flange 262 . Groove 265 is provide for receiving “O” ring 270 . In addition, FIG. 14 shows straight surface 266 of inside opening 267 and inside surface 274 of tubular section 257 .
[0122] The universal top adjustable alignment container of the present invention can also be fabricated of individual components, which can be welded together. By way of an example, top flange 262 can be welded at 271 to the tubular section 257 , and mud dam 269 can be made of a piece of thin steel welded to the outer periphery of top flange 262 . Any machining including the cutting of acme threads 256 and the drilling and tapping of holes 259 , 260 , and 264 can be done at the time each component is fabricated or after all or part of the components have been welded together.
[0123] Whether cast in one piece or fabricated of individual components, the universal top adjustable alignment container 255 preferably is made of stainless steel, to provide for corrosion resistance.
[0124] The alignments adjustments precision makes the apparatus of the present invention an efficient and economical apparatus and method for the replacement of conventional, existing fixed-length extensions at the time of renovation, i.e., resurfacing of aircraft ground traffic areas, as well as for new installations of such traffic areas by eliminating the need for installing fixed-length extensions, by eliminating the need for installing several flat spacer rings of various thicknesses, by eliminating the need for installing and angle-correcting, tapered spacer rings, i.e., leveling rings, and by eliminating the need for installing a separate mud dam. In addition, the installation of alignments adjustments assembly of the present invention saves labor costs, and the assembly is reusable.
[0125] Thus it can be seen that the invention accomplishes all of its objectives.
[0126] The apparatus and process of the present invention are not limited to the descriptions of specific embodiments presented hereinabove, but rather the apparatus and process of the present invention should be viewed in terms of the claims that follow and equivalents thereof. Further, while the invention has been described in conjunction with several such specific embodiments, it is to be understood that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing detailed descriptions. Accordingly, this invention is intended to embrace all such alternatives, modifications, and variations which fall within the spirit and scope of the appended claims.
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An airport inset light adjustable alignment container set provides a light fixture and stainless steel support for airport runway, taxiway, or other aircraft ground traffic areas. A variable length extension means rotatably adjusts height and azimuth by a rotatable vertical displacement. In one aspect, a previously installed, airport inset light and stainless steel base of the present invention receives a variable length extension assembly for rotatably adjusting the height and azimuth alignment of an airport inset light. Rotation locking means are provided for securing the rotatable adjustment apparatus from further rotation. A novel stainless steel base is adapted to receive various different designs of inset lights and, in one aspect, to provide a stainless steel protection ring “mud dam.”
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of forming an integrated circuit with NAND flash array segments and intra array multiplexers and to a corresponding integrated circuit with NAND flash array segments and intra array multiplexers.
2. Related Art
A flash memory is a non-volatile computer memory that can be electrically erased and reprogrammed. E.g. each flash memory may store information in an array of floating-gate transistors, often called cells. One example for a flash memory is a NAND memory which uses tunnel injection for writing and tunnel release for erasing.
As manufactures increase the density of data storage in flash devices, the size of an individual memory cell is shrinking. Also, the distance between two adjacent memory cells decreases. Therefore, it is a challenge to provide a high cell density as well as a sufficient stability of its components.
BRIEF DESCRIPTION OF THE FIGURES
The invention can be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
FIG. 1 a illustrates a schematic plain view of an embodiment of an integrated circuit and FIG. 1 b shows a schematic cross section of the integrated circuit;
FIG. 2 shows a flow chart of a first embodiment of the method of forming an integrated circuit;
FIG. 3 illustrates a schematic plain view of an embodiment of a brute force double patterning process of forming active areas;
FIG. 4 illustrates a schematic plain view of an embodiment of a brute force double patterning process of forming contacts;
FIGS. 5 a and 5 b illustrate schematic plain views of embodiments of a pitchfrag double patterning process of forming active areas;
FIGS. 6 a and 6 b illustrate schematic plain views of further embodiments of a pitchfrag double patterning process of forming active areas using a trim mask; and
FIGS. 7 a and 7 b illustrate alternative layouts with a joint of a source line and an inhibit voltage supply; and
FIG. 8 shows a flow chart of a second embodiment of the method of forming an integrated circuit.
DETAILED DESCRIPTION
In the following description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration one or more specific implementations in which the invention may be practiced. It is to be understood that other implementations may be utilized and structural changes may be made without departing from the scope of this invention.
FIG. 1 a illustrates a schematic plain view of an embodiment of an integrated circuit 10 and FIG. 1 b shows a schematic cross section of the integrated circuit 10 .
The integrated circuit 10 includes a number N1 of NAND flash array segments 20 and N1 intra array multiplexers 31 , 32 , each NAND flash array segment 20 is surrounded by a first and a second half 31 , 32 of the corresponding multiplexer. Reference sign 31 designates the first half or left half of the corresponding multiplexer and reference sign 32 designates the second half or right half of the corresponding multiplexer.
Each NAND flash array segment 20 has a number N2 of rows or active areas 41 - 43 . Further, the active areas 51 - 56 of the intra array multiplexers 31 , 32 may be formed by double patterning and may have a 3F width W 1 and a 1F pitch P 1 . Each row 41 - 43 or active area of the corresponding NAND flash array segment 20 has a local bit line 61 - 64 connected. The rows 41 - 43 may be formed by double patterning and may have a 1F width W 2 and a 1F pitch P 2 to each other.
The integrated circuit 10 has global bit lines 71 - 73 and local bit lines 61 - 64 . At least one global bit line 71 - 73 is connected to at least two local bit line 61 - 64 . Preferably, a respective global bit line 71 - 73 may be connected to at least two associated or neighbouring local bit lines 61 - 64 .
Preferably, the integrated circuit 10 further includes a number N4 of global bit lines, in particular with N4=½N2, the i th global bit line 71 - 73 is able to be connected to the (2i−1) th local bit line 61 , 63 and the (2i) th local bit line 62 , 64 , iε[1, . . . , N4], the global bit lines 71 - 73 are formed by double patterning and have a 2F width W 3 and a 2F pitch P 3 to each other.
That NAND flash array segment 20 forms a NAND flash array. In contrast to conventional NAND flash array segments, the total number of bit lines connected to the periphery of the NAND flash array is decreased, because not every row of the corresponding segment is coupled by a bit line connected to said periphery. In contrast, only the global bit lines 71 - 73 may be connected to the periphery, said global bit lines multiplexed to the local bit lines 61 - 64 coupling a respective row or string. Said multiplexing within said integrated circuit 10 or NAND flash array is provided by means of said N1 intra array multiplexers. The phrase intra within intra array multiplexer indicates that the intra array multiplexers are incorporated or integrated within the integrated circuit 10 .
That NAND flash array may have 32 to 128 word lines or rows forming a string or NAND string. Said string has a respective select transistor at its beginning and at its end. On the one end, said string is connected to source, and on the other end it is connected to bit lines. Said string structure recurs and, therefore, forms a NAND flash array segment 20 . After a predefined number of said strings, e.g. several hundreds or thousands, there is arranged an intra array multiplexer.
Further, each row 41 - 43 can have a number N3 of NAND strings 81 , 82 , wherein the corresponding local bit line 61 - 64 of the respective rows 41 - 43 is connected to the number N3 of NAND strings 81 , 82 . To increase the legibility of FIGS. 1 a and 1 b not all elements shown are comprised with reference signs.
Further, the first half 31 of the intra array multiplexer can have a first and a second transistor 91 , 92 for activating the (2i−1) th local bit line 41 , 43 , respectively. The first transistor 91 is able to connect the i th global bit line 71 with the (2i−1) th local bit line 41 , respectively. E.g. the first transistor 91 is able to connect the first global bit line 71 with the first local bit line 41 .
Further, the second transistor 92 can be able to connect the i th global bit line 71 with an inhibit voltage 101 , respectively. E.g. the second transistor 92 is able to connect the first global bit line 71 with the inhibit voltage supply 101 .
The second half 32 of the multiplexer can have a third and a fourth transistor 93 , 94 for activating the (2i) th local bit line 42 , 44 , respectively. In particular, the third transistor 93 is able to connect the (2i) th local bit line 62 to an inhibit voltage supply 102 , respectively. E.g. the third transistor 93 can be able to connect the second local bit line 42 with the inhibit voltage supply 102 .
Furthermore, the fourth transistor 94 may be able to connect the i th global bit line 91 with the (2i) th local bit line 62 , respectively. E.g. the fourth transistor 94 can be able to connect the first global bit line 71 with the second local bit line 62 .
The global bit lines 71 - 73 can be arranged over all N1 flash array segments 20 , wherein the local bit lines 61 - 63 are arranged over the corresponding NAND flash array segment 20 .
The first half 31 of the intra array multiplexer can have N4 global bit line contacts 111 - 113 , wherein the i th global bit line contact 111 can connect the i th global bit line 71 with the first transistor 91 , respectively E.g. the first global bit line contact 111 can connect the first global bit line 71 with the first transistor 91 .
The first half 31 of the intra array multiplexer can have N4 local bit line contacts 114 - 116 , wherein the i th local bit line contact 114 can connect the (2i−1) th local bit line 61 with the first transistor 91 , respectively. E.g. the first local bit line contact 114 can connect the first local bit line 61 with the first transistor 91 .
Further, the second half 32 of the intra array multiplexer can have N4 global bit line contacts 121 - 123 , wherein the j th global bit line contact 121 , jε[1, . . . , N4], can connect the i th global bit line 71 with the fourth transistor 94 , respectively. E.g. the first global bit line contact 121 can connect the first global bit line 71 with the fourth transistor 94 .
Furthermore, the second half 32 of the intra array multiplexer can have a number N4 of local bit line contacts 124 - 126 , wherein the i th local bit line contact 124 can connect the (2i) th local bit line 62 with the fourth transistor 93 , respectively. E.g. the first local bit line contact 124 can connect the second local bit line 62 with the fourth transistor 93 .
Also, contacts 133 can be provided over each NAND string 81 , 82 for connecting a corresponding bit line (not shown) with the underlying active area 41 .
A NAND flash array segment 20 comprises a source line 129 , a ground select transistor 130 , a number of word lines 131 and a bit line select transistor 132 . Without loss of generality, this is shown in FIG. 1 b for the first row of the integrated circuit.
FIG. 2 shows a flow chart of an embodiment of a method of forming an integrated circuit 10 . In the following, the method of forming an integrated circuit is explained with reference to the block diagram of FIG. 2 referring to the schematic plain view of FIG. 1 a and the schematic cross section of FIG. 1 b.
The embodiment of the method of forming an integrated circuit 10 has the method steps S 1 -S 4 as shown in FIG. 2 :
Step S 1 :
Active areas 41 - 43 for a number N1 of NAND flash segments 20 are formed by double patterning respectively a double patterning process, wherein each NAND flash segment 20 has a number N2 of rows 41 - 43 with a 1F width W 2 and a 1F pitch P 2 to each other.
Step S 2 :
Active areas 51 - 56 for a number N1 of intra array multiplexers 31 , 32 are formed by double patterning respectively a double patterning process, wherein the active areas 51 - 56 have a 3F width W 1 and a 1F pitch P 1 to each other
Step S 3 :
A local bit line 61 - 63 is formed over each row 41 - 43 respectively, each local bit line having a 1F width W 2 and a 1F pitch P 2 to each other.
Step S 4 :
A number N4 of global bit lines 71 - 73 ,
N 4 = 1 2 N 2 ,
is formed with a 2F width W 3 and a 2F pitch P 3 to each other by double patterning respectively a double patterning process such that a i th global bit line 71 - 73 is able to be connected to a (2i−1) th local bit line 61 , 63 and a (2i) th local bit line, iε[1, . . . , N4]. E.g. the first global bit line 71 is able to be connected to the first local bit line 61 and the second local bit line 62 . Further, the second global bit line 72 can be able to be connected to the third local bit line 63 and the fourth local bit line 64 .
Further to method steps S 1 -S 4 , the method of forming an integrated circuit 10 can have the following embodiments:
Each NAND flash array segment 20 can be surrounded by the first and second halves 31 , 32 of the corresponding intra array multiplexer. Further, a number N3 of NAND strings 81 , 82 can be formed within each row 41 - 43 , wherein the formed N3 NAND strings 81 , 82 can be connected with the corresponding local bit lines 61 - 61 . E.g. the first NAND string 81 and the second NAND string 82 within the first row 41 can be connected to the first local bit line 61 .
Further, the first half 31 of the intra array multiplexer can be provided with a first and a second transistor 91 , 92 for activating the (2i−1) th local bit line 41 , 43 , respectively. In this regard, the first transistor 91 can be formed to be able to connect the i th global bit line 71 with the (2i−1) th local bit line 41 , respectively. E.g. the transistor 91 can be able to connect the first global bit line 71 with the first local bit line 41 .
The second transistor 92 can be formed to be able to connect the (2i−1) th global bit line 71 with an inhibit voltage supply 101 , respectively. E.g. the second transistor 92 is formed to be able to connect the first global bit line 71 with the inhibit voltage supply 101 .
The second half 32 of the intra array multiplexer can be provided with a third and a fourth transistor 93 , 94 for activating the (2i) th local bit line 42 , 44 , respectively the even-numbered local bit line 42 , 44 , respectively. In this regard, the third transistor 93 can be formed to be able to connect the (2i) th local bit line 62 with an inhibit voltage supply 102 , respectively. E.g. the third transistor 93 can be formed to be able to connect the second local bit line 62 with the inhibit voltage supply 102 .
Further, the fourth transistor 94 can be formed to be able to connect the i th global bit line 71 with the (2i) th local bit line 62 , respectively. E.g. the fourth transistor 94 can be formed to connect the first global bit line 71 with the second local bit line 62 .
The global bit lines 71 - 73 can be arranged over all N1 NAND flash array segments 20 , wherein the local bit lines 61 - 63 can be arranged over only the corresponding NAND flash array segments. E.g. the first local bit line 61 is arranged only over the corresponding NAND flash array segment 20 . Further, the integrated circuit 10 can be formed as a memory device for a memory circuit.
Further, the active areas 41 - 43 for the N1 NAND flash segments 20 and the active areas 51 - 56 for the N1 intra array multiplexers 31 , 32 can be formed with one double patterning process at the same time or simultaneously.
Also, the first half 31 of the intra array multiplexer can be provided with N4 global bit line contacts 111 - 113 , wherein the i th global bit line contact 111 can connect the i th global bit line 71 with the first transistor 91 , respectively. E.g. the first global bit line contact 111 can connect the first global bit line 71 with the first transistor 91 .
Further, the first half 31 of the intra array multiplexer can be provided with N4 local bit line contacts 114 - 116 , wherein the i th local bit line contact 114 can connect the (2i−1) th local bit line with the first transistor 91 , respectively. That means that the N4 local bit line contacts 114 - 116 can connect the odd-numbered (by means of parameter i) bit lines 61 , 63 . E.g. the first local bit line contact 114 can connect the first local bit line 61 with the first transistor 91 .
Further, the second half 32 of the intra array multiplexer can be provided with a number N4 of global bit line contacts 121 - 123 , the j th global bit line contact, jε[1, . . . , N4], can connect the i th global bit line 71 with the fourth transistor 94 , respectively. E.g. the first global bit line contact 121 can connect the first global bit line 71 with the fourth transistor 94 .
Further, the second half 32 of the intra array multiplexer can be provided with a number N4 of local bit line contacts 124 - 126 , wherein the i th local bit line contact 124 can connect the (2i) th local bit line 62 with the fourth transistor 94 , respectively. E.g. the first local bit line contact 124 can connect the second local bit line 62 with the fourth transistor 94 .
Furthermore, the first half 31 of the intra array multiplexer can be provided with N4 local bit line contacts 114 - 116 , the i th bit line contact 114 can connect the (2i−1) th local bit line 61 with the first transistor 91 , the second half 32 of the intra array multiplexer can be provided with N4 local bit line contacts 124 - 126 , the i th local bit line contact 124 can connect the (2i) th local bit line 62 with the fourth transistor 94 , wherein the local bit line contacts 114 - 116 ; 124 - 126 are structured as stackered CB chain by lithography or by double patterning.
Further, the N4 global bit line contacts 111 - 113 at the first half 31 of the intra array multiplexer and the N4 global bit line contacts 121 - 123 at the second half 32 of the intra array multiplexer can be formed by a double patterning process, wherein the global bit line contacts 111 - 113 ; 121 - 123 can be landed on a contact 127 , 128 processed within a local bit line 114 - 116 ; 124 - 126 structuring processor on the respective local bit line 61 - 64 .
FIG. 3 illustrates a schematic plain view of an embodiment of the brute force double patterning process of forming active areas 51 - 56 of a first half 31 of an intra array multiplexer and active areas 41 - 49 of an NAND array segment 20 . In a first sub-step of the brute force double patterning process, the active areas 51 , 53 , 58 and 41 , 43 , 45 , 47 , 49 can be formed simultaneously. In a second sub-step of the brute force double patterning process, the active areas 52 , 57 and 42 , 44 , 46 and 48 can be formed simultaneously.
FIG. 4 illustrates a schematic plain view of an embodiment of the brute force double patterning process of forming contacts 201 - 208 for connecting a corresponding bit line (not shown) with the underlying active area 41 - 48 and local bit line contacts 301 , 303 , 305 , 307 of the active areas 54 , 55 , 56 , 59 of the second half 32 of the intra array multiplexer.
In a first sub-step of the brute force double patterning process, the contacts with an odd number, namely 201 , 203 , 205 , 207 , 301 , 303 , 305 and 307 , are formed simultaneously.
In a second sub-step, the contacts with an even number, namely 202 , 204 , 206 and 208 , are formed simultaneously.
The sequence of the first and second sub-steps of the brute force double patterning process as described with reference to FIGS. 3 and 4 can be changed.
FIGS. 5 a and 5 b show schematic plain views of embodiments of a pitchfrag double patterning process of forming active areas 51 - 55 of the first half 31 of an intra array multiplexer and active areas 41 - 49 of a NAND flash array segment 20 .
Before processing the pitchfrag double patterning, an active area 400 is provided which forms the basis for the intra array multiplexers 31 , 32 and the NAND flash array 27 .
Without loss of generality, the FIGS. 5 a and 5 b show only the first half 31 of one intra array multiplexer and one NAND flash array segment 20 .
After providing the active area 400 , carrier layers 401 used as a spacer for building an isolation area for the active areas are processed. Subsequently to the processing of the carrier layers 401 , spacer layers 402 are processed on the respective carrier layers 401 . By means of the spacer layers 402 isolation areas between neighbouring active areas of the first half 31 of the intra array multiplexer and the NAND flash array segment 20 can be processed.
Alternatively for dividing the first half 31 of the intra array multiplexer and the NAND flash array segment 20 as depicted in FIG. 5 a , a trim mask 403 as shown in FIG. 5 b can be used. The trim mask may be a hard mask.
In an analogous way, the FIGS. 6 a and 6 b show schematic plain view of embodiments of a pitchfrag double patterning process of forming contacts 501 - 516 .
Further, FIGS. 6 a and 6 b show the use of a CB mask 600 for defining the length of the contacts 501 - 516 .
As an alternative to the embodiment of FIG. 5 a , the FIGS. 7 a and 7 b show alternative layouts for an integrated circuit as shown in FIGS. 1 a and 1 b with a joint of source line 129 and inhibit voltage supply 101 processed by a pitchfrag double patterning process.
FIG. 8 shows a flow chart of a second embodiment of a method of forming an integrated circuit 10 . In the following, the method of forming an integrated circuit is explained with reference to the block diagram of FIG. 8 referring to the schematic plain view of FIG. 1 a and the schematic cross section of FIG. 1 b.
The embodiment of the method of forming an integrated circuit 10 has the method steps T 1 -T 4 as shown in FIG. 8 :
Step T 1 :
Active areas 41 - 43 for a number N1 of NAND flash segments 20 are formed, wherein each NAND flash segment 20 has a number N2 of rows 41 - 43 with a 1F width W 2 and a 1F pitch P 2 to each other.
Step T 2 :
Active areas 51 - 56 for a number N1 of intra array multiplexers 31 , 32 are formed, wherein the active areas 51 - 56 have width W 1 greater than 2F and a pitch P 1 to each other smaller than 2F.
Step T 3 :
A local bit line 61 - 63 is formed over each row 41 - 43 respectively, each local bit line having a 1F width W 2 and a 1F pitch P 2 to each other.
Step T 4 :
A number N4 of global bit lines 71 - 73 ,
N 4 = 1 2 N 2 ,
is formed with a 2F width W 3 and a 2F pitch P 3 to each other such that a i th global bit line 71 - 73 is able to be connected to a (2i−1) th local bit line 61 , 63 and a (2i) th local bit line, iε[1, . . . , N4]. E.g. the first global bit line 71 is able to be connected to the first local bit line 61 and the second local bit line 62 . Further, the second global bit line 72 can be able to be connected to the third local bit line 63 and the fourth local bit line 64 .
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The present invention provides an integrated circuit including N1 NAND flash array segments with N2 local bit lines, N1 intra array multiplexers and N2/2 global bit lines. Further, the present invention provides a method of producing an integrated circuit including N1 NAND flash array segments with N2 local bit lines, N1 intra array multiplexers and N2/2 global bit lines.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to railway crossing construction, and more particularly to prefabricated railway panel assemblies for installation at railway crossings.
2. Description of the Related Art
Railway tracks typically include a pair of steel rails supported on a plurality of traversely extending ties which in turn are supported on ballast material. At intersections with roadways, sidewalks and the like, the railway tracks are typically embedded so that the top surface of the rails are substantially the same height as the finish grade of the surrounding surface so that vehicles, pedestrians and the like may cross over the rails with minimal difficulty.
One typical way of embedding the rails includes installing gauge panels between the rails and field panels at opposite or outer sides of the rails such that a gap is formed between the rails and panels. Gaps must exist in order permit the flanged wheels of a train, car or other rail-guided vehicle to pass along the rails through the intersection without obstruction. These gaps also prevent the surrounding surface from contacting the rails, due to construction tolerances or surface shifting. However, the gaps between a rail and panels cause several problems. By way of example, foreign objects may become wedged in the gaps and present an obstacle for vehicles traveling along the rails, as well as for vehicles crossing the rails. Foreign objects and fluids may also fall through the gaps and accumulate between the rail and the surrounding surface. These fluids or foreign objects can damage the railway crossing system, such as the ballast, ties, attaching hardware, and so on. In order to address these problems, filler strips have been separately inserted into the gaps between the rails and panels, a time-consuming and labor-intensive task.
It has been proposed to bolt a filler strip directly to the panel at spaced locations, as shown for example in U.S. Pat. No. 4,415,120 issued to Thim. However, the filler strip may become wavy between mounting bolts and break the seal between the panel and rail, thus permitting liquid, dirt, and other debris to pass between the rail and panel.
SUMMARY OF THE INVENTION
According to the invention, a panel assembly is provided for installation at a railroad crossing. The panel assembly comprises a panel having a side surface adapted to face at least one of the rails. A filler strip has a sealing portion adapted to contact at least one rail and a mounting portion for connecting the filler strip to the panel. A reinforcing member extends along a length of the filler strip mounting portion such that the filler strip mounting portion is sandwiched between the reinforcing member and the panel side surface. A plurality of fasteners extend from the panel side surface through the filler strip and reinforcing member to thereby connect the filler strip to the panel. The reinforcing member provides structural rigidity to the filler strip.
Further according to the invention, a system for embedding a railway track having a pair of rails comprises a pair of field panels adapted for positioning opposite each other at outer sides of the rails and a gauge panel adapted for positioning between the rails. Each field panel has a side surface adapted to face its corresponding rail outer side and the gauge panel has opposite side surfaces adapted to face the inner sides of the rails. A first filler strip is associated with each of the field panels and a pair of second filler strips are associated with the gauge panel. Each of the first and second filler strips include a sealing portion that is adapted to contact one of the inner and outer rail sides and a mounting portion for connecting the filler strip to its respective panel. A reinforcing member extends along a length of each filler strip mounting portion such that each filler strip is sandwiched between its respective reinforcing member and panel side surface. A plurality of fasteners extend from the side surface of each panel, through its respective filler strip and reinforcing member to thereby connect the filler strip to the panel. The reinforcing member provides structural rigidity to the filler strip.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, wherein like designations denote like elements, and wherein:
FIG. 1 is a cross sectional elevational view of a railroad crossing incorporating the panel system of the present invention;
FIG. 2 is a top plan view of the railroad crossing and panel system of FIG. 1;
FIG. 3 is a cross sectional elevational view of a portion of the panel system taken along line 3 — 3 of FIG. 2;
FIG. 4 is an enlarged cross sectional view of the panel system of FIG. 3; and
FIG. 5 is a view similar to FIG. 3 illustrating installation of a gauge panel system.
It is noted that the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and to FIGS. 1 and 2 in particular, a railroad crossing 10 includes a pair of spaced rails 12 and 14 and a panel system 16 adapted to sealingly engage either side of the rails. The panel system 16 has a pair of field panels 18 and 20 that are positioned adjacent an outer side of the rails 12 and 14 , respectively, and a gauge panel 22 that is positioned between the rails. Filler strips 21 are connected to a rail side of the field panels 18 and 20 , while filler strips 23 are connected to opposite rail sides of the gauge panel 22 to sealingly engage the rails, as will be described in greater detail below. The panels 18 , 20 and 22 may be constructed of concrete or other durable material with high compressive strength. Although not shown, rebar may be embedded in the panel material for increased strength. The filler strips 21 and 23 are preferably extrusion formed of rubber or other suitable elastomer or plastic material.
The rails 12 , 14 are typically supported on ties 24 constructed of wood, concrete, or the like. Tie plates 26 (FIG. 3) may be provided between the ties 24 and the rails 12 , 14 . Spikes 28 may be driven into the ties to secure the rails and tie plates to the ties in a well-known manner. The ties 24 may be supported on a ballast layer 30 , which is in turn supported on a compacted suballast layer 32 of hot or cold mix asphalt, which is in turn supported on a compacted subgrade layer 34 . A non-woven geotextile fabric may be located between the ballast and suballast layers. Pipes or conduits 38 may be located in the ballast layer 30 and extend generally parallel to the rails 12 , 14 for accommodating signal wires or the like. Perforated drainage pipes 40 may also be located in the ballast layer 30 . A road surface 36 is located on either side of the panel system 16 and may be sloped or otherwise arranged to provide a relatively smooth transition between the railroad crossing 10 and the road surface 36 .
As illustrated in FIG. 2, depending on the width of the railroad crossing and length of each panel 18 , 20 and 22 , a plurality of panels such as left end panels 18 A, 20 A and 22 A, middle panels 18 B, 20 B and 22 B, and right end panels 18 C, 20 C and 22 C may be arranged to extend along the entire width of the railroad crossing. The panels 18 , 20 and 22 are also positioned on the ties 24 . A plurality of bores 50 are formed in each panel 18 , 20 , and 22 . The bores 50 extend through the thickness of each panel and are each sized to receive a fastener (not shown) to secure the panels to the ties 24 . Where the panels are not directly connected to the ties, the bores may be eliminated. An elastomeric layer 25 may be positioned between the panels and the ties. A pair of spaced slots or openings 52 are also formed in each panel for temporary connection to a lifting device (not shown) during installation of the panels at the railroad crossing 10 . As shown, a chamfer 54 may be formed at the left terminal edge of the left end panels 18 A, 20 A and 22 A, and a chamfer 56 may be formed at the right terminal edge of the right end panels 18 C, 20 C and 22 C. The chamfers 54 , 56 extend generally transverse to the rails 12 , 14 . A frame 60 surrounds an upper perimeter of each panel and is embedded into the panel material.
With reference now to FIGS. 3 and 4, the frame 60 is L-shaped in cross section and includes a substantially horizontal leg 62 that extends from a substantially vertical leg 64 . The frame 60 is preferably embedded in the panel during panel formation and serves in part to protect the edges of the panel from wear and chipping.
The rails 12 and 14 are of well-known construction and include a base flange 68 connected to a rail head 70 through a web 72 . The elongate side of the panels adjacent he rails are recessed, as shown by numeral 66 , in order to provide clearance for the base flange 68 , tie plates 26 and spikes 28 . A row of fasteners 74 , preferably in the form of threaded studs, extend away from the vertical leg 64 of each panel toward the web 72 for mounting the filler strips 21 and 23 to their respective panels. The studs are preferably fixedly connected to the vertical leg 64 through welding, but may alternatively be embedded in the panel material during formation of the panel.
The filler strip 21 includes a sealing portion 80 connected to a mounting portion 82 . Preferably, the sealing portion 80 and mounting portion 82 are integrally formed during an extrusion process. The sealing portion 80 extends between and abuts against the leg 64 of the frame 60 and the head 70 of the rail 12 when the filler strip 21 is mounted on the field panel 18 . A groove 84 is formed in the filler strip 21 and extends along the length thereof between the sealing portion 80 and mounting portion 82 . Bores 86 and 88 are formed in the sealing portion 80 and a bore 90 is formed in the mounting portion 82 to reduce the amount of material and thus reduce the cost of the filler strip 21 , as well as to provide some flexibility during compression of the filler strip to assure a tight seal. Rebar or the like (not shown) may be located in one or more of the bores to provide additional reinforcement to the filler strip 21 and connect adjacent panels together.
An elongate reinforcing member 92 is mounted to the field panels 18 , 20 . The reinforcing member 92 supports the filler strip 21 during installation of the field panels 18 , 20 and resists outside forces during use during use that may be caused by vehicles and foreign objects. The reinforcing member 92 may be constructed of metal such as steel or aluminum, fiberglass or other composites, plastic, or any other suitable material. The reinforcing member 92 preferably extends along the entire length of the filler strip 21 . The reinforcing member 92 is preferably U-shaped in cross-section with an upper leg 94 , a lower leg 96 and a plate 98 extending between the legs. The lower leg 96 is positioned against the lower surface 100 of the filler strip 21 , while the upper leg 94 is located in the groove 84 . The plate 98 includes a plurality of openings (not shown) coincident with the studs 74 so that a threaded portion of each stud extends outwardly of the plate. A nut 102 is threaded onto each stud 74 to compress the mounting portion 82 between the reinforcing member 92 and the vertical leg 64 and secure both the reinforcing member 92 and the filler strip 21 to the field panel 18 , 20 . In an alternative embodiment, the reinforcing member 92 may be L-shaped with the plate 98 serving as a mounting plate and one of the legs 94 , 96 serving as a ledge for supporting the filler strip 21 . A channel 104 may be formed along the length of the filler strip 21 to allow additional compression of the filler strip and assure a tight seal between the rail head 70 and field panel 18 , 20 . With this arrangement, the reinforcing member keeps the filler strip 21 straight and level with the top of the field panel and prevents the filler strip from being forced down when under pressure from vehicle traffic and foreign objects. The reinforcing member 92 also prevents the filler strip 21 from deforming upwards during installation of the field panel and throughout the service life of the filler strip 21 . This is a great advantage over prior art systems where the filler strips have been known to migrate upward when in service. The interlocking nature between the reinforcing member 92 and the filler strip 21 prevents upward movement of the filler strip 21 .
Each filler strip 23 includes a sealing portion 110 connected to a mounting portion 112 . Preferably, the sealing portion 110 and mounting portion 112 are integrally formed during an extrusion process. A sealing finger 114 is pivotally connected to the main body of the sealing portion 110 at an integrally formed hinge joint 118 . An outer free end 116 of the finger 114 abuts against the head 70 and/or the web 72 of the rail 12 when the filler strip 23 is mounted on the gauge panel 22 . The position of the finger 114 under the rail head 70 forms a channel 75 that receives the wheel flange of a rail-guided vehicle. A groove 120 is formed in the filler strip 23 and extends along the length thereof between the sealing portion 110 and mounting portion 112 . A bore 122 is formed in the mounting portion 112 to reduce the amount of material and thus reduce the cost of the filler strip 23 , as well as to provide some flexibility during compression of the filler strip to assure a tight seal. Rebar or the like (not shown) may be located in the bore 122 to provide additional reinforcement to the filler strip 23 and to connect adjacent panels together.
An elongate reinforcing member 130 is mounted to the gauge panel 22 . The reinforcing member 130 provides support for the filler strip 23 during installation of the gauge panel 22 and resists outside forces during use that may be caused by vehicles and foreign objects. The reinforcing member 130 is similar in construction to the reinforcing member 92 and preferably extends along the entire length of the filler strip 23 , with an upper leg 132 , a lower leg 134 and a plate 136 extending between the legs. The lower leg 134 is positioned against the lower surface 138 of the filler strip 23 , while the upper leg 132 is located in the groove 120 . The plate 136 includes a plurality of openings (not shown) coincident with the studs 74 so that a threaded portion of each stud extends outwardly of the plate. A nut 102 is threaded onto each stud 74 to compress the mounting portion 112 between the reinforcing member 130 and the vertical leg 64 and secure both the reinforcing member 130 and the filler strip 23 to the gauge panel 23 . In an alternative embodiment, the reinforcing member 130 may be L-shaped with the plate 136 serving as a mounting plate and one of the legs 132 , 134 serving as a ledge for supporting the filler strip 23 . A rear surface 140 of the filler strip 23 preferably extends at an obtuse angle with respect to the lower surface 138 before the filler strip 23 is mounted on the panel 22 so that a tight seal is formed between the filler strip 23 and the vertical leg 64 after mounting. With this arrangement, the reinforcing member 130 keeps the filler strip 23 straight and prevents the filler strip from being forced down when under pressure from vehicle traffic and foreign objects. The reinforcing member 130 also prevents the mounting portion 112 of the filler strip 23 from deforming upwards during installation of the gauge panel and throughout the service life of the filler strip 21 . This is a great advantage over prior art systems where the filler strips have been known to migrate upward when in service. The interlocking nature of the reinforcing member 130 and the filler strip 23 prevents upward movement of the filler strip 23 .
When the gauge panel 22 is first set in place between the rails 12 and 14 , and as shown in FIG. 5, the finger 114 of each filler strip 23 will initially rest on the upper surface of the rail head 70 . This feature is especially advantageous since the gauge panel can be lowered in a linear direction between the rails positioned more easily than the prior art method of canting the gauge panel during positioning. The fingers 114 are then pressed downwardly in a direction represented by arrow 142 by a tool (not shown) to slip the fingers 114 to a position under the rail head as shown in FIG. 3 . Once in position, the fingers 114 sealingly engage the rails and the reinforcing members 130 prevent the fingers from being forced further down during use.
It is to be understood that the terms left, right, middle, horizontal, vertical and their respective derivatives, as may be used throughout the specification, refer to relative, rather than absolute, positions and/or orientations.
While the invention has been taught with specific reference to the above-described embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and the scope of the invention. Thus, the described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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A system for embedding a pair of rails of a railway track comprises a pair of field panels adapted for positioning opposite each other at outer sides of the rails and a gauge panel adapted for positioning between the rails. Each field panel has a side surface adapted to face its corresponding rail outer side and the gauge panel has opposite side surfaces adapted to face the inner sides of the rails. A first filler strip is associated with each of the field panels and a pair of second filler strips are associated with the gauge panel. Each of the first and second filler strips include a sealing portion that is adapted to contact one of the inner and outer rail sides and a mounting portion for connecting the filler strip to its respective panel. A U-shaped reinforcing member extends along a length of each filler strip mounting portion such that each filler strip is sandwiched between its respective reinforcing member and panel side surface. A plurality of fasteners extend from the side surface of each panel, through its respective filler strip and reinforcing member to thereby connect the filler strip to the panel. The reinforcing member provides structural rigidity to the filler strip.
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BACKGROUND OF THE INVENTION
This application relates to a unique control and method for correcting errors in at least two different variables in a refrigerant system, wherein each of two error correction algorithms take into account an error signal from both variables.
Refrigerant systems typically include a compressor for compressing a refrigerant and a first heat exchanger receiving the refrigerant. Downstream of the first heat exchanger is an expansion device that expands the refrigerant. Adjustable expansion devices are known, that can be opened to varying amounts to change refrigerant pressure throughout the system. From the expansion device, the refrigerant travels to a second heat exchanger and then back to the compressor.
A control for the system is operable to take in inputs, such as a user demand for a particular hot water temperature at a faucet. Other applications may be to achieve a temperature in an environment conditioned by the refrigerant cycle (air conditioning or heat pump), and control aspects of the refrigerant cycle to achieve the demanded temperature. As an example, in one use of a refrigerant cycle, the first heat exchanger is utilized to heat water. Among the uses may be a hot water system for heating water.
In a hot water system, a control takes in an operator demand for a particular water temperature, and controls the amount of water flowing through the first heat exchanger. The more water that flows through the first heat exchanger, the lesser the temperature of the hot water at the outlet. Thus, to achieve higher temperatures for the water, the volume of water flow is reduced.
Further, and again to achieve the desired temperature demanded for the hot water, the refrigerant circuit must be controlled to provide sufficient heat at the first heat exchanger to heat the water to the desired temperature. Thus, two aspects of the hot water circuit must be controlled; the amount of water flowing through the first heat exchanger, and also an aspect of the refrigerant cycle. The amount of water delivered to the first heat exchanger can be controlled by controlling the speed of the water pump. In one embodiment, the refrigerant cycle is controlled in a system developed by the assignee of this application, by controlling the expansion device to provide a desired discharge pressure. Of course, a desired temperature or other condition could also be provided.
The controls for controlling the two variables, e.g., water pump speed and expansion device opening, typically have each taken into account an error, an integral of that error, and a derivative of this error. Such controllers are known as PID controllers. This type of controller is quite useful in controlling a condition, and providing feedback to adjust the condition such that it remains as desired. Such controls are known as single input, single output or “SISO.” These systems are somewhat sensitive to variations in some of the variables surrounding the system, as examples, ambient air temperature, the temperature of the water entering the heat exchanger, etc.
There is another deficiency in the above described control when the two control variables have an impact on each other. That is, as one of the variables, e.g., water pump speed, changes, it will change the pressure, yet the error correction algorithm for one variable does not anticipate the impact changes to the other will cause, until after the change has occurred. Thus, the efficiency of the overall system may not be as high as would be desired, in that each of the two variables would be sensitive to change in the other.
SUMMARY OF THE INVENTION
In a disclosed embodiment of this invention, a PID control calculates error correction values for each of two variables. The variables interact in such a way that a change in one results in a change in the other. An error correction algorithm for each of the variables considers the error in the other variable. Thus, the two error correction algorithms are better able to predict necessary change, by including a prediction of the change in the other variable.
While this control technique has wide application, in particular it is utilized in a system for supplying hot water. A main disclosed application is in a hot water heating system, where one of the variables is the speed of the water pump for moving the water through a first heat exchanger, and the other variable is a refrigerant condition within a refrigerant circuit for heating the water in the first heat exchanger. In the disclosed embodiment, the refrigerant condition is the discharge pressure of the refrigerant downstream of the compressor, and this variable is controlled by opening the expansion device. As the expansion device is closed down, pressure will increase. As the pressure increases, so does the temperature. Thus, as the refrigerant pressure is increased, it is likely that the temperature of the hot water leaving the first heat exchanger (“LWT”) would also increase. LWT is also controlled by varying the water pump speed, and thus as the refrigerant pressure increases, the pump speed may not need to decrease as much as would have previously been expected to achieve a demanded LWT. Thus, by considering the errors in both variables, the control is better able to adjust each of the variables more quickly to reach the desired states.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically shows a hot water heating system incorporating this invention.
FIG. 2 is a flowchart for this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A system 20 is illustrated in FIG. 1 for controlling the temperature at an end use 22 , such as a faucet. As known, a user of use 22 may set a desired temperature such as through a handle 25 . Hot water is supplied to a first heat exchanger 27 from a hot water supply line 24 to control the temperature at use 22 and meet the desired temperature. Such systems are known in the art, and the operation of this system forms no part of this invention.
Feedback from handle 25 goes to a central control 26 . Further, the discharge temperature 28 (LWT) of the hot water 24 leaving first heat exchanger 27 is also provided as feedback to controller 26 . The controller can identify a desired LWT based upon the demanded temperature from handle 25 . Actual LWT 28 is provided to the control 26 , and control 26 is operable to control the variable of the hot water supply system to adjust actual LWT 28 to meet the desired LWT. One such variable is the speed of the water pump 30 , for moving the water through a first heat exchanger 27 , and to use 22 . As the pump motor speed 30 decreases, the amount of water flowing through the heat exchanger 27 also decreases, and thus the water is heated to a greater temperature than if the speed of pump 30 is higher.
At the same time, a refrigerant 34 is flowing through the first heat exchanger 27 to heat the water. As known, the refrigerant is compressed by a compressor 36 , delivered to the first heat exchanger 27 , and then to an expansion device 38 . Expansion device 38 is adjustable, such that the size of its orifice can be adjusted to control conditions of the refrigerant 34 . Downstream of the expansion device 38 the refrigerant moves through a second heat exchanger 40 . From second heat exchanger 40 , the refrigerant returns to compressor 36 .
A system condition that is disclosed for controlling the condition of the refrigerant 34 is the discharge pressure 42 , downstream of the compressor 36 . Control 26 is operable to identify a desired pressure, and compare the actual discharge pressure at 42 to this desired discharge pressure. The control 26 adjusts the expansion device 38 to achieve change in the actual discharge pressure 42 such that it moves toward the desired discharge pressure. A method of determining the desired discharge pressure is disclosed in co-pending patent application Ser. No. 10/793,489, filed on even date herewith, and entitled “Pressure Regulation in a Transcritical HVAC System.”
Preferably, not only the error between actual LWT and the desired LWT is taken, but the control 26 preferably also takes the derivative of that error, and the integral of that error. The same is true of an error between the desired and actual 42 discharge pressure. Such controls are known as PID controllers, and are well known in the art.
With the system illustrated in FIG. 1 , there is some challenge in controlling the two variables, in that a change in one variable results in a change in the other. Thus, as for example, if refrigerant discharge pressure changes, it will in turn affect the LWT 28 . Further, a change in the amount of water flowing through the first heat exchanger 27 will change how much heat is taken out of the refrigerant 34 , and thus impact upon the discharge pressure 42 . To date, the two variables are controlled independently, and thus are sensitive to changes in each variable, such that reaching the desired steady state sometimes take longer than would be desired, and overall system efficiency is effected.
Generally, the desired discharge pressure to achieve the desired LWT is based upon various experimental data developed (as disclosed in the above-referenced patent application) to achieve the highest co-efficient of performance (COP), or the highest system efficiency. Thus, losing efficiency by not properly controlling the system would harm one of the main goals of having selected the desired pressure.
The refrigerant 34 is preferably a refrigerant capable of operation as part of a transcritical cycle. In one disclosed embodiment, the refrigerant is CO2. In a transcritical cycle, compressor discharge pressure is not dictated by saturation properties, and thus the above-referenced patent application provides a method of achieving a good deal of control over the overall cycle.
However, the problem of two variables might make achieving the efficiency goals somewhat difficult. The present invention improves upon the independent control of the two variables by incorporating the error signal from each of the variables into both error correction algorithms. A basic flowchart is provided at FIG. 2 . In the disclosed algorithms, the correction factor for both the hot water temperature and the refrigerant pressure includes both errors, a derivative of both errors, and the integral of both errors. The several factors are weighted by different constants, but are considered in each. Disclosed error correction algorithms for the adjustment of the expansion valve signal u EXV , and the control signal for the water pump speed, u VSP , are as follows:
u EXV = Kp 11 e P + Kp 12 e t + Ki 11 ∫ e p ⅆ t + Ki 12 ∫ e T ⅆ t + Kd 11 ⅆ e p ⅆ t + Kd 12 ⅆ e T ⅆ t
u VSP = Kp 21 e P + Kp 22 e T + Ki 21 ∫ e P ⅆ t + Ki 22 ∫ e T ⅆ t + Kd 21 ⅆ e P ⅆ t + Kd 22 ⅆ e T ⅆ t
e p is the pressure error, i.e., the difference between actual and desired compressor discharge pressure. e t is the temperature error, i.e., the difference between actual and desired delivery water temperature. K p11 , K p12 , . . . etc., are numerical constants. The constants K would be selected based upon the system, and also based upon the expected change that a particular change in water pump speed, for example, would have on the pressure. There are many methods for choosing the constants. The preferred method is the H ∞ (“H infinity”) design method, as explained for example in the textbook “Multivariable Feedback Design” by J. M. Maciejowski (Addison-Wesley, 1989). Note that according to these equations, u EXV and u VSP depend both on the current pressure and the current temperature. This is what makes the controller “multivariable.” A “single-variable” controller would have u EXV depend only on the pressure and u VSP depend only on the temperature.
In addition, there is preferably an adjustment to provide for correction and avoiding a particular condition wherein both the error for water temperature, and the derivative of the error are negative. This algorithm essentially utilizes an error that is the multiple of the detected error multiplied by the derivative of the detected error when both are negative. In this way, an otherwise potentially inefficient condition can be avoided. Details of this correction algorithm are disclosed in U.S. patent application Ser. No. 10/793,486, filed on even date herewith, and entitled Non-Linear Control Algorithm in Vapor Compression Systems.
Control 26 reads the current values of pressure and temperature from the corresponding sensors, computes u EXV and u VSP using the formula above, and sends these values to the expansion valve and water pump respectively. This procedure is repeated periodically (for example, every two seconds).
Essentially, the error correction algorithms above consider the error in both variables for calculating a correction factor for each variable. In this way, the correction factor anticipates the change in the other variable.
Of course, other error correction algorithms are within the scope of this invention. The invention broadly extends to the concept of controlling two variables with an error correction algorithm that incorporates error information for both variables into each error correction algorithm. Also, any type of suitable control may be used.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
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A control particularly useful for a hot water heating system, includes calculation of a desired leaving water temperature for water leaving a hot water heat exchanger, and a desired refrigerant condition for most efficiently achieving the desired leaving water temperature. A control looks at both desired variables and compares them to actual variables to determine an error for each. The control includes an error correction algorithm for each of the two variables that takes into account both of the errors, the integral of both of the errors, and the derivative of both of the errors. In this way, sensitivity in the error correction for one variable due to changes in the other variable is reduced, and the system functions more efficiently.
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This application is a continuation-in-part of U.S. application Ser. No. 08/134,085, filed Oct. 8, 1993, now U.S. Pat. No. 5,494,124.
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for conditioning the flow of fluid. The invention is believed to have a wide variety of applications, especially in the fabrication and use of calibrated or focused nozzles to create a fluid jet having unique characteristics.
Nozzles are used to create fluid jets in industries such as the oil and gas industry, among other things, to inject and mix fluids and to cleanse and erode surfaces. For example, during oil and gas drilling operations, drilling bits tear away at rock in a well bore while nozzles inject jets of drilling fluid into the well bore. The jets of drilling fluid may be used to assist in the erosion or cleaning of rock from the surface of the well bore by aggressively impinging on the surface. The fluid jets also may be used to clean rock fragments from the teeth of the drill bits.
When a nozzle is used for the purpose of eroding or cleaning a surface, the nozzle creates a fluid flow that impinges upon that surface. In many applications, the fluid flow is a "single-phase" flow in which the fluid flowing through the nozzle is a substantially homogeneous liquid (e.g., water). When pressure is applied to a single-phase fluid in the nozzle, a single-phase fluid jet impinges upon the surface and imparts energy to particles at the surface. Frequently the energy transferred from the fluid jet to the surface particles imparts momentum to the surface particles, thereby separating the particles from the surface. Such a separation of surface particles leads to an erosion or cleaning of the surface.
Improved ability and efficiency in separating the particles from the surface have been achieved through "multi-phase" fluid flow. For example, "dual-phase" flow may occur when gases are introduced into the liquid flowing through the nozzle, and "three-phase" flow may occur when particulate materials are entrained along with gas and/or liquid into the fluid. Multi-phase flow produces different erosion or cleaning characteristics from single-phase flow.
The fluid flow produced by a nozzle also may mix fluids and particles both at and away from an impingement surface. In any fluid flow, the presence of turbulent kinetic energy (i.e., turbulence) creates agitation within the fluid. Agitation produces a mixing phenomenon in the fluid which is beneficial, for example, in combining eroded rock fragments with the flowing fluid, thereby enhancing the ability of rock fragments to be carried out of the drilling area.
While the use of fluid jets generally for eroding, cleaning and mixing is well known in the art, room for improvement exists. For example, energy transfer between fluid jets and impingement surfaces can be carried out with greater efficiency. In addition, agitation created by the presence of turbulent kinetic energy can be increased.
SUMMARY OF THE INVENTION
The invention provides improved eroding, cleaning and mixing capabilities in fluid flow. Greater levels of erosion, cleaning and mixing are achieved for the expended energy, and thus more efficient fluid flow is produced. Eroding and cleaning capabilities are enhanced, in part, because the invention produces a pressure maximum and a pressure minimum (e.g., a strong positive pressure and a strong negative pressure) at substantially the same axial distance from the source of the flow. Mixing capabilities are increased as a result of increased turbulent kinetic energy throughout the flow region. The invention may also produce a region of turbulent kinetic energy at substantially the same axial distance from the source of the maximum and minimum pressure regions. The invention may calibrate, or focus, fluid flow to provide minima and maxima in set locations.
The invention has utility in conjunction with an impingement surface. Fluid contacts the impingement surface in a manner that produces regions of positive and negative pressure at the surface. In addition, the fluid flow creates a region of turbulence which lies at the surface. As a result, the fluid flow not only imparts pressure to the impingement surface, but also pulls material away from the surface. The fluid flow also enhances the effects of turbulence away from the impingement surface.
In general, in one aspect of the invention, a method of conditioning a flow of fluid includes the steps of introducing a fluid into a nozzle body, directing the fluid introduced into the nozzle body over an inner surface of the nozzle body, and applying a pressure to the fluid. The nozzle body has an opening defining an inlet and an opening defining an outlet. The inner surface of the nozzle body connects the inlet to the outlet and is eccentric throughout its longitudinal dimension. Applying pressure to the fluid provides a first region outside the nozzle of relative maximum pressure and a second region outside the nozzle of relative minimum pressure, where the first and second regions are substantially the same distance from the outlet.
Embodiments of the invention include the following features. The step of directing the fluid may comprise focusing the fluid such that the first region of relative maximum pressure and the second region of relative minimum pressure occur at a predetermined distance. The step of introducing a fluid into a nozzle body includes the additional steps of forming an axisymmetric inlet and forming an asymmetric outlet. The outlet may also be circular. The step of introducing a fluid may also include the step of forming an outlet which is symmetric-periodic or N-lobe periodic in shape, as well as the step of forming a circular inlet. The method of conditioning a flow of fluid may further include the step of directing the conditioned fluid against an impingement surface to provide a negative pressure thereon. The step of introducing a fluid into a nozzle body may comprise introducing liquid into the nozzle body or introducing gas into the nozzle body. This step also may comprise introducing a multi-phase flow into the nozzle body or introducing a particulate material into the fluid.
In general, in another aspect of the invention, a fluid-conditioning nozzle comprises an inlet having an edge defining a first circumference, an outlet having an edge defining a second circumference, and a transition surface extending between the inlet and the outlet. The second circumference is smaller than the first circumference and the outlet is offset from and spaced apart from the inlet. The transition surface is eccentric throughout its longitudinal dimension between the first and second circumferences, and the nozzle is operable to provide a first region outside the nozzle of relative maximum pressure and a second region outside the nozzle of relative minimum pressure, where the first and second regions are substantially the same distance from the outlet.
Embodiments of the invention include the following features. The inlet, the outlet, and the transition surface may be focused such that the first region of relative maximum pressure and the second region of relative minimum pressure occur at a predetermined distance. The outlet may be symmetric-periodic or N-lobe periodic in shape, and the inlet may be substantially circular in shape. The inlet and the outlet both may be substantially circular or substantially elliptical in shape. The transition surface may be linear or may curve between the first and second circumferences. The transition surface may also have a different slope at diametrically opposed locations at the circumference of the outlet. The nozzle may comprise cast metal or molded plastic.
In general, in another aspect of the invention, a fluid-conditioning nozzle comprises a substantially circular inlet having a first radius R 1 and a first centerline, a substantially circular outlet having a second radius R 2 and a second centerline, and a transition surface extending between the inlet and the outlet. The second radius R 2 is smaller than the first radius R 1 . The second centerline is parallel to the first centerline, and the first and second centerlines are offset a radial distance d from each other. The inlet and the outlet are spaced apart in axial distance L from each other. The transition surface has a longitudinal cross-section defining a first edge with a first slope A 1 and a second edge with a second slope A 2 , where the first edge and the second edge are at diametrically opposed locations on the transition surface. The first slope A 1 and the second slope A 2 are defined by the equation:
tanA.sub.1 +tanA.sub.2 =(2R.sub.1 -2R.sub.2)/L.
The radial distance d is defined by the equation:
d=R.sub.1 -R.sub.2 -L(tanA.sub.2).
The inlet, the outlet and the transition surface are cooperable to provide a first region outside the nozzle of relative maximum pressure and a second region outside the nozzle of relative minimum pressure, where the first and second regions are substantially the same distance from the outlet. In specific embodiments of the invention, the first and second cross-sectional edges may be either linear or curved.
In general, in another aspect of the invention, a method of manufacturing a nozzle comprises the steps of forming an inlet and an outlet in a nozzle body, the inlet and the outlet being eccentric, joining the inlet and the outlet with a transition surface having an edge of first perimeter at a first end in contact with the inlet and having an edge of second perimeter at a second end in contact with the outlet, and tapering the transition surface through the nozzle body such that the second edge perimeter is smaller than the first edge perimeter. The inlet, the outlet and the transition surface cooperate to define a fluid passage through the nozzle body, and the nozzle is operable to provide a first region outside the nozzle of relative maximum pressure and a second region outside the nozzle of relative minimum pressure, where the first and second regions are substantially the same distance from the outlet. In specific embodiments of the invention, the step of tapering the transition surface may comprise forming either a linear surface or a curved surface through the nozzle body, and the inlet and the outlet may be either substantially circular, substantially elliptical, or periodic in shape.
Other features and advantages of the invention will become apparent from the following description of the preferred embodiments and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are described below, with reference to the following drawings.
FIG. 1 is a cross-sectional view in a longitudinal plane of a prior fluid nozzle.
FIGS. 2 through 4 show regions of pressure and turbulence created by prior fluid nozzles.
FIGS. 5 and 6 are longitudinal cross-sectional views of nozzles in accordance with the present invention.
FIGS. 7 through 9 show regions of pressure and turbulence created by the nozzles of FIGS. 5 and 6.
FIG. 10 is an end view of the nozzles of FIGS. 4 and 5.
FIGS. 11 and 12 are longitudinal cross-sectional views of alternative nozzles in accordance with the present invention.
FIGS. 13 and 14 are a longitudinal cross-sectional view and an end view of an alternative nozzle in accordance with the present invention.
FIG. 15 is end view of an alternative embodiment of a nozzle in accordance with the present invention.
FIG. 16 shows regions of pressure created by the nozzle of FIG. 15.
FIG. 17 is an end view of an alternative embodiment of a nozzle in accordance with the present invention.
FIG. 18 is a perspective view of a nozzle in accordance with the present invention.
FIG. 19 is an outlet end view of a nozzle in accordance with the invention having a tri-legged slot outlet extending into a frustoconically shaped passageway.
FIG. 20 is a longitudinal semi-cross-sectional view of the nozzle of FIG. 19.
FIG. 21 is an outlet end view of a nozzle in accordance with the invention having a cross-shaped slot outlet extending into a frustoconically shaped passageway.
FIG. 22 is a longitudinal semi-cross-sectional view of the nozzle of FIG. 21.
FIG. 23 is a diagram of contour lines of relative pressure projected by a fluid forced through the nozzle of FIGS. 19 and 20.
FIG. 24 is a diagram of contour lines of relative pressure projected by a fluid forced through the nozzle of FIGS. 21 and 22.
FIG. 25 is a schematic representation of a zone of negative hydrostatic pressure impinging a rock-cutter interface and zones of positive pressure along which fluid vortices are shedding.
FIGS. 26 through 29 are alternative embodiments of an outlet perimeter of a nozzle in accordance with the invention.
FIG. 30 is a longitudinal cross-sectional view of an alternative embodiment of a transition surface in accordance with the invention.
DESCRIPTION OF PRIOR NOZZLES
Referring to FIG. 1, fluid enters a typical nozzle 102 though a cylindrical inlet 106 and exits the nozzle 102 through a circular outlet 108, which is concentric with and diametrically smaller than the inlet 106. Between the inlet 106 and the outlet 108 is a tapering transition surface 112, which forms a conical nozzle passage 114 in the nozzle body 110. A longitudinal centerline 116 exists though the inlet and the nozzle passage 114, and defines the center 120 of the outlet 108. At all points around its perimeter, the transition surface 112 forms a constant angle A with respect to the longitudinal centerline 116, and thus is axisymmetric in shape. An axisymmetric body is one which mirror images itself in any longitudinal, cross-sectional plane.
As fluid flows through the inlet 106, the transition surface 112 alters the dynamics of the flow, forcing the fluid to converge toward the centerline 116. Because the fluid passage 114 is axisymmetric, fluid flows through the outlet 108 with substantially uniform magnitude of velocity and at a substantially uniform angle with the centerline 116 at all points of equal radial distance from the centerline 116. For example, fluid flowing directly adjacent the transition surface 112 leaves the outlet 108 with a velocity of magnitude w and at an angle A with respect to the centerline 116 at all points around the perimeter of the outlet 108. Thus, like the nozzle itself, the flow of fluid from the nozzle is axisymmetric about the longitudinal centerline 116.
Referring to FIG. 2, fluid flowing from the outlet 108 may impinge upon a surface 124 substantially normal to the general direction 126 of the fluid flow. As this happens, a region of positive impingement pressure 128 occurs at the surface 124 by action of the fluid (i.e., the fluid "pushes" on the surface). The point of greatest positive pressure on the impingement surface 124 occurs at the centerline 116. At points increasingly distant from the centerline 116, the magnitude of positive pressure on the surface 124 tends to decrease. At some location 130 along a radial path from the centerline 116, the fluid exerts no substantial impingement pressure on the surface.
As may be seen in FIG. 3, regions of substantially equal impingement pressure are represented by pressure contour lines 132, as viewed from the nozzle. Region I is the region of greatest impingement pressure, with the most positive fluid pressure lying on the centerline 116. The impingement pressure in region II is lower than that of region I but greater than the pressure in region III, which in turn is greater than the pressure in region IV. In all of regions I through IV, the fluid flow exerts a positive impingement pressure upon the surface 124. Region V covers the remainder of the impingement surface, upon which the fluid flow exerts no significant impingement pressure.
Referring again to FIG. 2, fluid flowing from the nozzle 102 also creates a region of negative pressure 134. This toroidal region of negative pressure 134 is axisymmetric about the centerline 116 and distanced in the axial direction from the impingement surface 124. The negative pressure region 134 results when fluid flows away from the centerline 116 and forms eddy currents.
As depicted in FIG. 4, the flow of fluid from the typical nozzle 102 also produces axisymmetric regions of turbulence 136a and 136b. Turbulence in zone or region 136a is in the shape of a hollow cylinder, axisymmetric about the centerline 116. Turbulence in zone or region 136b is toroidal in shape, is wider in diameter than region 136a and surrounds the end of region 136a closest to the impingement surface. Together, regions 136a and 136b form an axisymmetric "top hat-shaped" region of turbulence that surrounds the longitudinal centerline 116 and that is axially distanced from the impingement surface 124.
Non-axisymmetric nozzles are also known in art. These nozzles typically have a circular inlet and non-circular outlet, with a common centerline passing throughout the nozzle. The characteristics of non-axisymmetric nozzles known in that art are similar to those of the axisymmetric nozzle described above.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 5, a nozzle 150 fashioned in accordance with the present invention includes a generally cylindrical nozzle body 152 in which a fluid passage 154 is formed. The nozzle body may be made of many different types of materials, depending upon the application. In downhole drilling applications, for example, the nozzle must be of great strength with high abrasive resistance, so a strong metal, such as tungsten, preferably should be used. For less rigorous applications, such as hot tubs, spas and the like, the nozzle may be made of a plastic or a ceramic material. The fluid passage 154 is preferably formed by milling the nozzle body with a numerically controlled automated machine tool. However, any suitable means may be used, including casting or molding.
At one end of the fluid passage 154 is an inlet throat 156 of generally circular cross-section in axial plane P1 (FIG. 5). At the other end of the fluid passage 154 is a generally circular outlet 164 of smaller diameter, and thus smaller circumference, than the inlet throat 156. The inlet throat 156 and the outlet 164 have parallel centerlines, denoted 160a and 160b, respectively, which are offset by a radial distance d. Thus, the inlet throat 156 and outlet 164 are eccentric, i.e., they do not share a centerline.
Between the inlet throat 156 and outlet 164, the fluid passage 154 defines a transition surface 166. The transition surface is a linear surface of generally circular cross-section in any axial plane P2 (FIG. 5). Because the inlet throat 156 and the outlet 164 are eccentric, the transition surface 166 forms a non-axisymmetric "offset cone." A transition centerline 160c intersects the inlet centerline 160a where the transition surface 166 meets the inlet throat 156 to form an edge, or transition inlet 158, and intersects the outlet centerline 160b at the outlet 164. Transition centerline 160c is a "centerline" in the sense that, for any axial plane P2 (FIG. 5), the centroid 162 of the circular cross-section of the transition surface 166 lies on the transition centerline 160c.
When viewed in longitudinal cross-section, the transition surface 166 forms diametrically opposed angles B and C (FIG. 5) with respect to centerlines 160a and 160b. The relationship between the angles is determined by the equation:
tanB+tanC=(2R.sub.c -2R.sub.j)/L.sub.CONE
where R c is the radius of the transition inlet 158, R J is the radius of the outlet 164, and L CONE is the axial distance between the transition inlet 158 and the outlet 164. The offset d of centerlines 160a and 160b is determined by the equation:
d=R.sub.c -R.sub.j -(tanC)L.sub.CONE
The offset "cone" is typically constructed such that angles B and C are both between 0° and 50°. A "cone" in which one of the angles B and C equals 0° is shown in FIG. 11. The "cone" may also have a region in which the transition surface forms negative angles, as shown in FIG. 12.
Because the geometric slope continuously changes around the perimeter of the transition surface 166, fluid exits the passage 154 at velocities which continuously vary in magnitude and angle in both the radial and angular directions with respect to the outlet centerline 160b. Fluid flowing along the transition surface 166, for example, passes diametrically opposed points of the outlet 164 with velocity vectors u and v (FIG. 5). Velocity vector u forms an angle B with centerline 160b, whereas velocity vector v, of smaller magnitude than vector u, forms an angle C with outlet centerline 160b. Between the vectors u and v, no two adjacent outflow vectors along the perimeter of the outlet 164 have equal magnitude or form the same angle. Thus, the offset cone nozzle creates a fluid jet that is asymmetric about the outlet centerline 160b. This asymmetry has been found to have beneficial results, as will be discussed in more detail below.
Referring to FIG. 6, in an alternative form, the fluid passage 154' may be defined by a non-linear transition surface 166' between the inlet throat 156' and outlet 164'. As with the linear nozzle, the inlet centerline 160a' and the outlet centerline 160b' are offset by a radial distance d' (FIG. 6). However, instead of abutting the inlet throat 156' with a different slope, the slope of the transition surface 166' at the inlet throat 156' is substantially equal to the slope of the inlet wall. The transition surface 166' then gradually changes the slope of the passage 154' between the inlet throat 156' and outlet 164'. At the outlet 164', the transition surface 166 forms diametrically opposed angles B' and C' with centerline 160b', as discussed with respect to the linear-surface nozzle above. As with the linear-surface nozzle, fluid flows out of the non-linear-surface nozzle with diametrically opposed velocity vectors u' and v' (FIG. 6). In FIG. 6, if d=0 (i.e., if the inlet throat 156' and outlet 164' are coaxial), then the inlet throat 156' and the outlet 164' are symmetric, but the transition surface 166' remains asymmetric with respect to the inlet centerline 160a,b. In the embodiments of FIGS. 5 and 6, for most, and preferably all, axial cross-sections of the transition surface, the centroid of the cross-sectional region 163 does not lie on the inlet centerline 160a.
FIG. 10 is an inlet end view of the nozzle of either FIG. 5 or FIG. 6 that illustrates the cross-sectional region 163 formed where the axial plane P2 intersects the transition surface 166. The centroid 162c of the region 163 is the geometric center of the region, i.e., the two-dimensional "center of mass." In the preferred embodiments, the centroid 162c does not coincide with the center 162a of the inlet 158, and thus does not lie on the inlet centerline 160a. In FIG. 10, the inlet centerline 160a runs normal to the page, intersecting the page at the centroid 162a of the inlet. The transition centerline 160c is the locus of the centroids of every axial cross-sectional region in the transition surface 166. The transition surface is therefore eccentric throughout its longitudinal dimension.
Referring to FIG. 7, the fluid jet produced by the nozzle 150 follows a generally curved path 168 toward an impingement surface 170. As a result, the general thrust of the flow of fluid impinges the surface 170 at an angle, with respect to centerline 160b, which is normal to the impingement surface 170. Non-normal impingement of the fluid produces on the impingement surface 170 a region of positive pressure 172, the magnitude distribution of which resembles an egg-shaped dome. The region of maximum pressure lies in the vicinity of the intersection between the centerline 160b and the surface 170.
In addition, the fluid flow produces a region of negative pressure 174, which in shape resembles an irregular torus that is asymmetric about centerline 160b. The region of negative pressure bends toward the impingement surface 170, such that at least a portion, and preferably a large portion, of the negative pressure region 174 lies on the impingement surface 170. As a result, the regions of relative maximum and minimum pressure are formed at substantially the same distance from the nozzle 150. The nozzle 150 may be focused such that the regions of relative maximum and minimum pressure occur at predetermined distances from the outlet 164' (FIG. 6).
Referring to FIG. 8, contour lines around line-of-symmetry 176 show that a primary negative pressure region 174 is established at the impingement surface 170 in a generally crescent-like or horseshoe-like shape. The greatest negative pressure upon the surface 170 lies in a crescent-shaped maximum negative pressure region VI, and the pressure becomes decreasingly negative until it reaches substantially zero at the extremities 175 of a crescent-shaped intermediate negative pressure region VII. In addition to the primary negative pressure region 174, a secondary negative pressure region 178 may form on the impingement surface 170, centered at a position diametrically opposed to the maximum negative pressure region VI. At very high flow rates an entire torus of negative pressure 174 may be established at the impingement surface 170, so that a complete ring of negative pressure is formed around the outside of the positive pressure region 172. The radial distances between the positive pressure region 172 and the negative pressure regions 174 and 178 depend upon the geometry of the perimeter of the outlet 164 and the transition surface 166, as well as the fluid flow parameters such as flow rate, viscosity, and the like.
The regions of positive and negative pressure produced by the nozzle 150 on the impingement surface 170 lead to advantages before unrealized in the art. For example, the enlarged region of positive pressure 172 (FIG. 8) leads to greater erosion and cleaning of the surface. The regions of negative pressure 174 and 178 (FIG. 8) create a "pulling" action on the surface, thus enabling the fluid to tear material or particles away from the surface. With a nozzle fashioned in accordance with the present invention, the ability of fluids to clean and erode solid surfaces is significantly enhanced.
Referring to FIG. 9, in addition to the negative pressure regions, fluid flowing from the nozzle produces a region of turbulent kinetic energy 180 which is established at the impingement surface 170. Like the negative pressure region, the region of turbulence 180 is asymmetric, and it resembles an irregular truncated torus that substantially continuously acts upon the impingement surface 170. The region of turbulence 180 also may be concentrated or focused into a single, non-toroidal region on the impingement surface, depending upon flow conditions. Such a non-toroidal region may be tuned to coincide with a region of maximum negative pressure, or it may be offset some angle about the outlet centerline 160b from the regions of maximum negative pressure, again depending upon flow conditions and nozzle geometry. Fluid flowing from the nozzle also enhances other regions of turbulent kinetic energy throughout the well bore.
The turbulent kinetic energy produced by the fluid flow from the nozzle 150 is believed to be at least three times as great as that from the prior art nozzle of FIG. 1. Turbulent kinetic energy may be defined as the dot product of the time averaged velocity vector fluctuations v', or ρ·K, where ρ is the mass density of the fluid, and K is the "turbulence measure," both well-known in the art. For the velocity vector v having fluctuation components v' 1 , v' 2 and v' 3 , turbulence measure is defined by the equation:
K=1/2<ν.sub.1.sup.2 +ν.sub.2.sup.2 ν.sub.3.sup.2 >
Experimental data has shown that for nozzles according to the invention, K is at least three times that of the prior art nozzle of FIG. 1. One result is that the fluid flow from nozzle 150 has enhanced fluid mixing qualities over known nozzles.
Referring to FIG. 11, the nozzle 150 also may be constructed such that, at a predetermined location 182, the transition surface 166 has zero slope and thus runs parallel to centerlines 160a and 160b, forming a "right-angle" cone. In this embodiment, the angle formed between the fluid jet and centerline 160b continuously changes around the perimeter of the outlet 164 until, at the location of zero slope 182, fluid exits the nozzle in a direction normal to the impingement surface.
Referring to FIG. 12, a further alternative embodiment is shown. In particular, the nozzle 150 may be further modified so that the angle formed between the transition surface 166 and centerline 160b not only reaches zero, but becomes negative, reaching a maximum negative angle of -C. In regions where the slope of the transition surface 166 is negative, fluid flowing through the outlet 164 will actually diverge from centerline 160b.
FIGS. 13 and 14 show another alternative embodiment. FIG. 13 is a longitudinal cross-section of the nozzle and FIG. 14 is the nozzle as viewed through the inlet throat 156". The inlet throat 156" of the fluid passage 154" is defined by a surface 156a" of substantially circular cross-section comprising a tapering neck 156b" that abuts a substantially cylindrical portion 156c". The tapering neck 156b" allows the inlet surface 156a" to transition from the larger diameter of the inlet mouth 156d" to the smaller diameter of the transition inlet 158". From the transition inlet 158", the transition surface 166" tapers toward the eccentric outlet 164" at diametrically opposed angles B" and C", preferably of 5° and 35°, respectively. The outlet 164" is also generally circular and of smaller diameter than the transition inlet 158". At the transition inlet 158", the transition surface 166" and the inlet surface 156a" do not meet at different angles, but rather cooperatively form a rounded intersection 158a" to ensure smooth transition between the two surfaces.
In each of the embodiments of FIGS. 11 through 14, the centroid of each axial cross-sectional region lies on a transition centerline which does not coincide with the inlet centerline 160a. The effects on fluid flow of these alternative embodiments are similar to those of the nozzles of FIGS. 4 and 5.
Referring to FIG. 15, the offset cone geometry may also be used to form an elongated nozzle 190. In the elongated nozzle 190, a rectangular-cubical nozzle body 192 contains a rectangular inlet 194, whose width is greater than that of a rectangular outlet 196. The longitudinal centerline 195 of the outlet 196 is offset from the longitudinal centerline 193 of the inlet 194, so that a cross-section in plane P3 resembles the cross-section of the circular nozzle 150 of FIG. 5. Instead of creating a fluid jet, the elongated nozzle 190 creates a substantially planar fluid flow which may be used, e.g., as a fluid knife.
Referring also to FIG. 16, the elongated nozzle 190 creates substantially elongated pressure regions having a relatively high aspect ratio when compared with the pressure regions of other nozzles depicted, e.g., in FIG. 8. A positive pressure region 198 is formed on the impingement surface 170 around the orthogonal projection of centerline 195. Surrounding the positive pressure region 198 is an asymmetric irregular loop of negative pressure, part of which intersects the impingement surface 170 in an elongated crescent-shaped region of negative pressure 200. A second, smaller region of negative pressure 202 may also be formed on the impingement surface 170, opposite region 200.
The elongated nozzle 190 provides the benefits of the circular nozzle but over a wider area and with a higher aspect ratio. This arrangement facilitates enjoyment of the benefits of the invention in applications such as seafood processing, textile treatment (e.g., carpet cleaning), paint removal, and other such applications. For example, the elongated nozzle 190 could be placed into a sweeper which, when passed over carpet, allows the positive and negative pressure regions to form on the carpet surface, thereby dislodging and removing particles from the carpet.
Referring to FIG. 17, a further alternative embodiment is shown, whereby the nozzle of FIGS. 5 and 6 includes a nozzle passage that is noncircular in shape. The non-circular nozzle 210 comprises a nozzle body 212, into which an oblong conical fluid passage 214 is formed. The passage 214 has an oblong inlet 216, which is generally elliptical or ovular in shape. From the inlet 216, an elliptical-conical transition surface 218 tapers through the nozzle body 212 towards an oblong outlet 220 of smaller perimeter than the inlet 216. The center of the outlet 220 is offset from the center of the inlet 216. This offset may be along the minor axes 222 of the inlet 216 and outlet 220, the major axes 224, or some combination of the two (major and minor axes, as used here, do not necessarily conform to the meaning of these terms as used in the mathematical definition of an ellipse). The inlet and the outlet also may be rotated with respect to each other, e.g., by 90°, so that the minor axis of the inlet 216 is parallel to the major axis of the outlet 222, and vice versa. The dynamics of the fluid jet produced by the non-circular nozzle 210 are similar to those described above for the circular nozzle. However, certain advantages are provided by a nozzle having a higher aspect ratio.
An improved nozzle in accordance with the invention may be used to replace the nozzles typically used in the art under either single-phase or multi-phase flow conditions. A useful application for the nozzle is in downhole drilling operations using tri-cone and fixed-cutter drill bits. As shown in FIG. 18, a substantially cylindrical nozzle 230 has a diameter as required by flow area limitations and is inserted into a drilling bit of size specific to the given applications in a manner known to those of skill in the art. As the drill bit is rotated within a well bore and, in the case of the tri-cone bit, as the roller cones tear away at the rock within the bore, pressure is applied to fluid in the nozzle 230, thereby creating a fluid jet. The fluid jet exits the nozzle 230 and impinges upon the teeth of the drill bit and/or the rock surface. Because of the features of the fluid flow described above, the teeth of the drill bits may be better and more efficiently cleaned, the rock surface may be better and more efficiently eroded, and/or the fluid within the well bore may be better and more efficiently mixed with cuttings than would be expected with prior nozzles. As a result, the drilling operation becomes faster and more efficient.
Other alternative embodiments do not necessarily include a transition surfaces which are eccentric throughout, but instead may be formed with transition surfaces that are symmetric or axisymmetric about a centerline. Referring to FIG. 19, a nozzle 240 is depicted in end view. The nozzle 240 includes a nozzle body 248 which is substantially cylindrical in shape and centered along a longitudinal axis 244. Also centered on the longitudinal axis 244 is an outlet 246, in the form of a tri-legged or star-shaped slot, each leg 246a, 246b and 246c of which is of equal length from the longitudinal axis 244. Line D--D on FIG. 19 denotes the location of the semi-cross-sectional view of the nozzle 240 along one leg 246a, as shown in FIG. 20.
Referring also to FIG. 20, nozzle body 248 defines a passageway 250, a semi-cross-sectional portion of which is shown. The passageway 250 includes an inlet throat 254 at the end of the nozzle body 248 opposite the outlet 246. Between the inlet throat 254 and the outlet 246 is a first transition surface 256 which tapers inwardly toward the longitudinal axis 244 at a predetermined angle (e.g., 35°) from the longitudinal axis 244. The first transition surface 256 defines a frustoconical surface, the imaginary apex of which lies on a point of projection 252 on the axis 244 outside the nozzle 240 and beyond the outlet 246. The passageway 250 includes a second transition surface 258 that intersects the first transition surface 256. The second transition surface 258 tapers inwardly at a greater angle than the first transition surface, forming a slotted shape in the less steeply rising first transition surface 256. Similar semi-cross-sectional portions are found in each of the other two legs 246b and 246c of the outlet 246.
Referring to FIG. 21, a nozzle 270 includes a nozzle body 278 which is columnar in shape and centered along a longitudinal axis 274. Also centered on the axis 274 is an outlet 276 in the form of a four-legged or cross-shaped slot, each leg 276a, 276b, 276c and 276d of which is of equal length from the axis 274. Line E--E on FIG. 21 denotes the location of the semi-cross-sectional view of the nozzle 270 along one leg 276a, as shown in FIG. 22.
Referring also to FIG. 22, the nozzle body 278 defines a passageway 280, a semi-cross-sectional portion of which is shown. The passageway 280 includes an inlet throat 284 at the end of the nozzle body 278 opposite the outlet 276. Between the inlet throat 284 and the outlet 276 is a first transition surface 286 which tapers inwardly toward the longitudinal axis 274 at a predetermined angle (e.g., 35°) from the longitudinal axis 274. The first transition surface 286 defines a frustoconical surface, the imaginary apex of which lies at a point of projection 282 on the axis 274 outside the nozzle 270 and beyond the outlet 276. The passageway 280 includes a second transition surface 288 that intersects the first transition surface 286. The second transition surface 288 tapers inwardly at a greater angle than the first transition surface 286, forming a slotted shape in the less steeply rising first transition surface 286. Similar semi-cross-sectional portions are found in each of the other three legs 276b, 276c and 276d of the outlet 276.
The nozzle of FIGS. 19 and 20 was tested in a fixture as follows. The nozzle body had an overall length of 2.75 inches, an outside diameter of 2.375 inches, a single leg width of 0.289 inches and a single leg length of 0.650 inches. Total area of the nozzle outlet was 0.5 in 2 . A tank of dimensions 4.15 feet long, 3.69 feet wide and 2 feet deep having a capacity of 229.09 gallons was employed with a 3 by 2 centrifugal pump acting on water as a test fluid. A pressure/vacuum transducer model PU350 manufactured by John Fluke Manufacturing Company, Inc., capable of measuring 0-500 psig with full vacuum function, with analog to digital voltmeter readout was employed with a pressure measuring fixture comprising a flat plate translatable in two axes, one perpendicular to flow, the other parallel to flow. A 3/8 inch OD×3/16 inch ID nipple projected 3/16 inch above the plate. Pressure readings were taken at 1/4 inch increments perpendicular to the flow from center of the jet to three inches radially outward from the centerline. Flow rate was 165 gpm, plate depth was 12 inches below the static waterline, nozzle discharge pressure was 68 psig static, pressure at the plate was 0 psig (transducer calibrated to read zero at 12 inches depth), the nozzle to plate distance was 1.625 inches, and water temperature was 100° F. The resulting first derivative topographical pressure profile is depicted in FIG. 23.
The mapped pressure profile of FIG. 23 shows that the nozzle of FIGS. 19 and 20 produces a tri-lobular zone 290 of positive hydrostatic pressure that degrades from a maximum positive value in a core portion 292 thereof at its center and at its lobes 294 to a zero reference value in distal peripheries 295 thereof. Furthermore, the nozzle of FIGS. 19 and 20 produces zones of negative hydrostatic pressure 296a, 296b, 296c adjacent and between each union of a lobe leg of the high pressure zone 290. Each of these zones of negative hydrostatic pressure degrades from a maximum negative value in a core portion 298 to a zero reference value at a distal pressure periphery 299. The negative zones are symmetrically spaced and substantially equidistant from adjacent leg extremities 295 of the core portion 292 of the positive zone 290.
The nozzle of FIGS. 21 and 22 was tested under the same conditions as the nozzle of FIGS. 19 and 20, except that the water temperature was 90° F. The nozzle body had an overall length of 2.75 inches, and outside diameter of 2.375 inches, a single cross arm width of 0.220 inches and a single cross arm length of 1.292 inches. Total area of the nozzle outlet was 0.5 in 2 . The resulting first derivative topographical pressure profiles are shown in FIG. 24.
The mapped pressure profiles of FIG. 24 show that the nozzle of FIGS. 21 and 22 produces a cruciform zone 290' of positive hydrostatic pressures that degrades from a maximum positive value in a central core portion 292' thereof at its center to a zero reference value in distal peripheries 295' thereof. Furthermore, the nozzle of FIGS. 21 and 22 produces zones of negative hydrostatic pressure 296a', 296b', 296c', and 296d' adjacent and between each union of a cross arm of the high pressure zone 290'. Each of these zones of negative hydrostatic pressure degrades from a maximum negative value in a core portion 298' to a zero reference value at a distal pressure periphery 299'. The negative zones are symmetrically spaced substantially equidistant from adjacent arm extremities 295' of the core portion 292' of the positive zone 290'.
Referring to FIG. 25, a nozzle 430 (as depicted in FIG. 19 or FIG. 21) is mounted in the body 410 of a drill bit. Fluid flowing from the nozzle forms vortices 490 just in front of the face 450 of a cutter 420 protruding from the bit body 410. High pressure areas 470 lie between the vortices 490, while low pressure areas 480 lie outside the vortices 490. The vortices 490 are essentially located around the periphery of the high pressure areas 470. This relationship between the vortices and the pressure zones, due to the design of the nozzle and its location in the drill bit, gives rise to the beneficial features of the nozzles of FIGS. 19 through 22.
Referring to FIGS. 26 and 27, further alternative embodiments of the outlet are shown, in which the shape of the outlet is a "symmetric-periodic" curve. The symmetric-periodic outlet has a line-of-symmetry 300 (FIG. 26) or 300' (FIG. 27) containing a reference point 302 (FIG. 26) or 302' (FIG. 27). The outlet is formed such that for every angle θ and the corresponding angle -θ from the line of symmetry 300 (FIG. 26) or 300' (FIG. 27), the perimeter of the outlet is a predetermined radial distance R (FIG. 26) or R' (FIG. 27) from the reference point 302 (FIG. 26) or 302' (FIG. 27).
Referring to FIGS. 28 and 29, further alternative embodiments of the outlet are shown, in which the shape is an "N-lobe periodic" curve. The N-lobe periodic outlet has a centroid 310 (FIG. 28) or 320 (FIG. 29) from which the perimeter of the outlet is at the same radial distance r (FIG. 28) or r' (FIG. 29) at points 312a, 312b, and 312c (FIG. 28) or 322a and 322b (FIG. 29), separated from each other by an angle of 2π/N. FIG. 28 illustrates an embodiment having three lobes (N=3), and FIG. 29 illustrates an embodiment having two lobes (N=2).
Nozzles containing embodiments of the outlet as shown in FIGS. 26 through 29 preferably have a circular inlet. Because of the complex structure of the transition surface connecting the circular inlet to the illustrated outlets, it is not required, but is preferred, that the centroid of each axial cross-sectional region of the transition surface lie on a transition centerline that does not coincide with the inlet centerline.
As shown in FIG. 30, an alternative embodiment of the transition surface is a "toroidal cone" 350. The transition surface 350 joins an inlet 352 and an outlet 354, both of which are circular, which lie in non-parallel planes having a line of intersection 356. The transition surface 350 is formed such that any plane containing the line of intersection 356 intersects the transition surface in a circular cross-sectional region 358. The "centerline" 360 of the transition surface 350 is the curve which contains the center points of every cross-sectional region of the toroidal cone created by planes containing the line of intersection 356.
Other embodiments are contemplated to fall within the scope of the following claims. The nozzle may be used in a wide variety of eroding, cleaning and mixing applications.
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A method of conditioning a flow of fluid comprises the steps of introducing a fluid into a nozzle body having an opening defining an inlet, an opening defining an outlet, and an inner surface connecting the inlet and the outlet, directing the fluid introduced into the inlet of nozzle body over the inner surface, and applying a pressure to the fluid. The inner surface of the nozzle is asymmetric with respect to a centerline of the inlet to provide a first region outside the nozzle of relative maximum pressure and a second region outside the nozzle of relative minimum pressure, where the first and second regions are substantially the same distance from the outlet. A fluid-conditioning nozzle comprises an inlet having an edge defining a first circumference, an outlet, offset from and spaced apart from the inlet, having an edge defining a second circumference, smaller than the first circumference, and a transition surface extending between the inlet and the outlet. The transition surface has a continuously changing slope between the first and second circumferences. The nozzle is operable to provide a first region outside the nozzle of relative maximum pressure and a second region outside the nozzle of relative minimum pressure, where the first and second regions are substantially the same distance from the outlet.
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A portion of the disclosure of this patent document contains material which is subject to copyright protection. The owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
This application claims priority from U.S. provisional application Ser. No. 60/010,304, filed Jan. 22, 1996, the disclosure of which is incorporated herein by this reference.
TECHNICAL FIELD OF THE INVENTION
This invention relates to novel, improved devices for radiation shielding, and to methods for fabricating and using the same. Devices of that character are well suited for use in protecting personnel from ionizing radiation in nuclear power plants, and in particular are well suited for reducing the dosage of ionizing radiation received by personnel when working around valves and pipes.
BACKGROUND OF THE INVENTION
During maintenance and overhaul of nuclear power plants, personnel are frequently required to perform operations that bring them into close proximity to locations which have the potential to accumulate, and thus emit, potentially harmful ionizing radiation. A common site at which an accumulation of radioactive substances occurs is at valves which are located in any piping that has or is carrying a radioactive substance. Often, such radioactive contamination occurs in a water or steam circuit line.
In the prior art, various types of shielding have been applied to valves in an attempt to limit the radiation exposures of personnel. Generally, the prior art apparatus and methods known to me are too cumbersome, and they are not particularly well adapted to being secured in place for long term radiation protection. As a result, the overall radiation dosage received by nuclear plant workers could be appreciably reduced with the availability of improved radiation shielding devices, and in particular, with improved devices that are suitable for being left in place to shield against radiation emanating from valves and piping during long term plant operations.
One important problem which must also be overcome with respect to any lead based radiation shield design is the potential for contamination of lead by existing radioactively contaminated materials, as that would result in further contamination since the lead may itself become radioactive. In other words, the use of a lead shield necessitates protection of such a lead shield, to avoid the possibility of further contamination, of either the lead itself, or of the underlying area due to lead becoming deposited thereon. This problem is further aggravated when the shields are placed in locations subject to high temperature or to water spray. Depending upon the anticipated service, a radiation shield may be subject to various adverse or harsh operating conditions, and thus the design must accordingly be capable of reliably protecting the lead during such service.
Currently, when it becomes necessary to work on or near pipe runs which are emitting an appreciable radiation dosage, common practice has been to use a type of wool blanket, or lead shot bags, or lead strips. Each of such apparatus and the methods for their use are somewhat effective in reducing radiation dosage, but in each case, their use has certain drawbacks, including:
(1) the equipment is too bulky (especially in the case of a lead wool blanket);
(2) the equipment is prone to leak (such as in the case of lead shot bags, where loss of lead causes other contamination problems); and
(3) installation of the apparatus is too time consuming (such as in the case of installation of lead sheet strips).
The configuration of piping or components in and around valves often limits the amount of the types of such aforementioned radiation shielding which could be placed around a valve. Further, if a valve itself has to be operated, or requires maintenance, placement of such radiation shielding is even further limited, because the placement of shielding can not restrict the operability of the valve, and can not prevent maintenance on the valve.
Radiation shielding devices which provide some of the general capabilities desired have heretofore been proposed. For the most part, prior art devices do not provide permanently affixable radiation shield designs, and thus are inherently not well suited for many of the applications which are of interest to me. Some radiation shielding devices are not suitable for exposure to moderate or high temperatures, or to water spray environments, due to use of a vinyl plastic sheet as a protective surface material. Other portable shields are designed for protection of large areas during major outages, and thus are so large and unique as to be inapplicable for most of the smaller applications of interest to me.
As a result, there still remains an unmet and a continuing need to provide an improved radiation shielding apparatus and method for radiation shielding of valves, and particularly small valves, in a manner that overcomes the deficiencies of the equipment and methods which have been used in the prior art. Specifically, there is an ongoing need for an improved radiation shield for valves which:
(1) allows for rapid and simple installation; and
(2) provides effective attenuation of ionizing radiation;
(3) has the assurance that retrieval is possible without encountering adverse lead contamination; and
(4) decreases the shield size, and therefore,
(5) increases accessibility to the shielded valve to allow many operation and maintenance operations to be conducted with protective shielding in place.
Consequently, I have developed novel radiation shields, and methods for their installation, which provide radiation shields that are superior to earlier radiation shielding apparatus and techniques which are known to me. The advantages offered by my novel radiation shield designs, which are permanently mountable and which may be provided in sizes which are transportable by a single worker, yet be removable and cleanable, are important and self-evident.
SUMMARY OF THE INVENTION
I have now invented, and disclose herein, a novel, radiation shield for use in attenuating exposures of radiation workers to ionizing radiation. Unlike radiation shields heretofore available, my shields are simple to build, particularly for custom applications, easy to install, relatively inexpensive, easy to use while avoiding undesirable lead contamination, and are otherwise superior to the heretofore used or proposed radiation shield devices for valves of which I am aware.
In one exemplary embodiment my radiation shield is provided in specially designed shields which are adapted to fit over the body of an existing valve, and to accommodate existing piping adjacent to the valve. Each shield consists of two or more separable portions (preferably two "half-round" shapes) which are interfitingly juxtaposed, and preferably interlocked, when installed in their operating, shielding position. Also, the separable portions are preferably uncoupled for installation and for removal. Preferably, at least one locking or fastening latch mechanism is provided for securing the separable portions one to the other. Most preferably, a hinge mechanism is provided at one side of each of the of separable portions (separable half-rounds, in the ideal case), and the hinge mechanism also preferably serves to secure the pair of separable portions to each other, thus allowing rapid installation. The separable shield portions can then be fastened or locked together on side of the half-rounds opposite the hinge, so that the half-rounds cooperate to form a finished shield with full coverage around the pipe or valve being shielded. Where appropriate, shield portions can be secured in place by various means, such as tape, wire ties, or steel bands.
My novel radiation shields are simple, durable, and relatively inexpensive to manufacture. In use, they provide a significant measure of reduction in radiation exposure to workers, by virtue of their ease of use in areas which were heretofore difficult to shield, and thus provide a significant improvement in a radiation shield device for valves.
OBJECTS, ADVANTAGES, AND FEATURES OF THE INVENTION
From the foregoing, it will be apparent to the reader that one important and primary object of the present invention resides in the provision of novel radiation shield devices which can be custom fabricated to fit the particular needs of a given application, in order to minimize installation difficulties while maximizing the effective dosage exposure reductions ultimately achieved.
Other important but more specific objects of the invention reside in the provision of radiation shields for valves which:
can be used in radioactively contaminated areas with minimal risk of contamination by the lead from the shield;
can be provided in a simple coating that allows use in moist environments;
which can be used in direct contact with stainless steel piping, valving, and components;
are relatively simple, particularly in manufacture and installation, to thereby enable the devices to be easily prefabricated and installed for unique applications; and
which can be easily decontaminated.
My radiation shields are also advantageously provided with coating materials which have additional important and more specific objectives, in that they:
can be easily used in areas which may encounter high pressure spray;
can be used in radioactively contaminated areas with a minimum of risk of contaminating the lead in the shield;
can be used on or around piping and components requiring that the shielding be protected against moisture, heat, and high temperature water or steam;
Coated radiation shields fabricated as described herein can be custom built, and specially designed and fabricated, and which are:
compatible with direct stainless steel contact;
easy to decontaminate;
able to withstand exposure to water or spray;
easy to install and to remove.
Other important objects, features, and additional advantages of my invention will become apparent to the reader from the foregoing and from the appended claims and as the ensuing detailed description and discussion proceeds in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 illustrates an end view of a typical radiation shield for a valve, shown installed about a valve in a pipe run; this view shows the compactness of the shield, and its configuration in a manner which would not interfere with the operation of the valve.
FIG. 2 illustrates a side elevation view of the typical radiation shield for a valve as just set forth in FIG. 1; this side view again shows how my novel radiation shield shield avoids interference with valve operation.
FIG. 3 illustrates a top view of a typical radiation shield for a valve, as just set forth in FIGS. 1 and 2 above, again showing how my novel radiation shield fits around an operating valve.
FIG. 4 shows an end view of one half-round of the radiation shield first set forth in FIG. 1 above, showing the approximate size and shape of an exemplary embodiment of my novel radiation shield apparatus.
FIG. 5 shows an end view of one half-round of a radiation shield, complimentary to the one-half round just set forth in FIG. 4, showing the shape of an exemplary embodiment of my novel shield.
FIG. 6 shows a side elevation view of my radiation shield for a valve, showing the overall shape when used for a typical globe valve.
FIG. 7 shows a top plan view of one separable portion, here one half-round of my shield, similar to the one-half round first illustrated in FIG. 4 above.
FIG. 8 shows a top plan view of a second separable portion of a radiation shield for valves, complimentary to the one-half round just set forth in FIG. 7, as illustrated in a configuration for use with a typical globe valve.
FIG. 9 is a perspective view of complimentary "half-round" portions of my radiation shield for valves.
FIG. 10 illustrates a perspective view of my novel radiation shield for valves, such as may be used for a typical globe stop valve in the 1/2 inch to 1 inch range.
FIG. 11 illustrates a side view of a typical one-half round for use with a globe stop valve. shows, from an end, a cross-sectional view of a first complementary portion of a shield for a typical 1/2 inch to 1 inch globe stop valve.
FIG. 12 shows an top view of a first one-half round portion of a radiation shield for a typical globe stop valve, as often seen in the one-half to one inch size range.
FIG. 13 shows an top view of a second one-half round portion of a radiation shield for a typical globe stop valve, as often seen in the one-half to one inch size range.
FIG. 14 shows an end view of a first one-half round portion of a radiation shield for a typical globe stop valve, as often seen in the one-half to one inch size range.
FIG. 15 shows an end view of a second one-half round portion of a radiation shield for a typical globe stop valve, as often seen in the one-half to one inch size range.
FIG. 16 illustrates two complimentary radiation shield portions in an open position, ready for installation around an existing valve.
FIG. 17 illustrates the reverse side of two complimentary shield portions in an open position, similar to the shield first set forth in an open position in FIG. 16 above.
In the various figures of the drawing, identical features will be indicated with identical reference numerals, and similar features in alternate embodiments or locations may be indicated by use of prime (') superscripts, without further mention thereof, as may be appropriate.
DETAILED DESCRIPTION
My invention can be easily understood and appreciated by considering the application for shielding a typical globe valve 20, as is shown in hidden lines in FIGS. 1, 2, and 3. My specially designed radiation shield 22 is shaped to fit over the outer surface or body 24 of globe valve 20, and adjacent piping 26. The fit of the first 28 and second 30 inner surfaces of shield 22 must be in a size large enough to fit around the body 24 of the valve 20, as seen in FIGS. 1 and 2. Ideally, the shield 22 has a relatively close fitting relationship with the pipe 26 and valve 29, especially with the upper reaches 32 of the valve 20, as is illustrated in FIGS. 1 and 3. Also, the shield 22 may be sized so that the inlet 34 and outlet ends 36 (along the longitudinal axis of piping 26) are each sized complementary to the size of the piping 26, so that the first 28 and second 30 inner surfaces of shield 22 fit close to or against pipe 26 in a close fitting, or even abutting, complimentary relationship, as can be appreciated from FIGS. 4 and 5, where a relatively close fit to outer piping surface 26' is illustrated for first 28 and second 30 inner surfaces. Alternately, piping sometimes is accompanied by an insulating layer (not shown), and the configuration shown in FIG. 1 is in such cases appropriate, to allow room for an insulating layer around the pipe 26 below first 28 and second 30 inner surfaces of shield 22.
Each radiation shield 22 comprises complimentary separable portions, preferably "half-rounds" or first 40 and second 42 separable portions. These first and second separable portions 40 and 42 are preferably interfitingly interlocked when installed in their operating, shielding position substantially surrounding valve 20 in an effective radiation attenuation manner. The two or more separable portions, here half-rounds 40 and 42, can be uncoupled for installation on or for removal from partially surrounding valve 20.
The first separable portion 40 and said second separable portion 42 each are manufactured from an effective radiation attenuation solid composition in a thickness suitable for effective attenuation of ionizing radiation. Preferably, the main radiation attenuation solid composition utilized is lead or bismuth, as these can be provided in easily cast parts. The first and second separable portions 40 and 42 are of complimentary size and shape for being releasably joined as a matching pair in a closed, shielding position to form a shell, such as is clear in FIGS. 1 and 3, having a partially closed internal chamber C therebetween formed by internal walls 28 and 30. Ideally, the internal chamber C has internal walls 28 and 30 which are shaped for complementary close fitting engagement with a portion of a valve 20 and a portion of a pipe 26'.
In one embodiment, as set forth in FIGS. 4 and 5, an interlocking engagement tab 50, and complementary receiving receptacle 52, are provided for interlocking engagement of the first separable portion 40 with the second separable portion 42. An alternate hinge arrangement is noted in FIGS. 16 and 17.
Preferably, my radiation shield is provided with a first separable portion 40 and a second separable portion 42 which are complimentary shaped to form, when engaged in an adjoined relationship, a hollow, substantially cylindrical chamber of radial wall thickness T between inner surfaces 28 or 30 and outer surfaces 54 and 56, respectively.
Turning now to FIGS. 7, 8, and 9, as noted above, the shield 22 extends lengthwise between an inlet end 34 and an outlet end 36. Extending substantially between the inlet end 34 and the outlet end 36, the first 40 and second 42 separable portions each have a lower abutting wall section, 60 and 62, respectively. Also, the first 40 and second 42 separable portions each have one or more, and preferably a pair, of upper abutting wall portions respectively. On first separable portion 40, abutting wall portions are noted as 64 and 66, and on second separable portion 42, abutting wall portions are noted as 68 and 70, respectively.
An upwardly disposed opening U is located between and inward surface I 1 and I 2 defined between the opposing pairs of upper abutting wall portions, 64-68 and 66-70, respectively, and inward surfaces I 3 and I 4 which arise upward from the outer surfaces 54 and 56, respectively. The upwardly disposed opening U is generally sized for upward extension of at least a portion of valve 22 therethrough. The inward surfaces I 1 , I 2 , I 3 , and I 4 have companion outer surfaces O 1 , O 2 , O 3 , and O 4 that define therebetween an upwardly disposed perimeter wall with portions of thickness W. Each of the perimeter wall portions 80, 82, 84, and 86 extend upwardly from the outer surfaces 54 and 56 of the first and second separable portions 40 and 42 to cooperatively form a perimeter wall substantially surrounding at least a portion of valve 20.
As noted in FIG. 5, and as also evident from FIG. 9, the radiation shield 22 preferably has a thick walled tubular body member of substantially annular partial cross-section of wall thickness T 1 extending between an inner surface 30 and an outer surface 56, and extending along a lengthwise axis between an inlet end 34 and an outlet end 36.
Turning now to a second embodiment of my radiation shield, as seen in FIGS. 10-17, a shield 122 can also advantageously be provided with angular disposed tubular portions, rather than with an open top with perimeter wall as illustrated in FIGS. 1-9 above. In such a case, first 140 and second 142 separable portions, have first and second axes, respectively, which meet at an angle Y. Along each axis is are disposed a central hollow cylindrical portion having an interior wall, 128 and 130 along the first or primary axis C L1 , and 128' and 130' along the secondary axis C L2 respectively. The cylindrical portion along the secondary axis is angularly and upwardly disposed toward an opening UU, which is defined by the inside walls 128' and 130' from the cylindrical portions 190 and 192. The angularly and upwardly disposed opening UU extending angularly and upwardly from the inner surface 128 and 130 of each of the first 140 and second 140 separable portions to cooperative form therebetween a thick walled tubular body member of substantially annular partial cross-section of wall thickness T 2 extending between an inner surface 130' and an outer surface 156'. This thick tubular wall provides an angularly and upwardly disposed opening generally sized surrounding and providing for upward extension of at least a portion of a valve therethrough, in a manner that radiation emanating therefrom can be attenuated.
Also illustrated in FIGS. 10, 12, 16 and 17 is a hinge mechanism and latch which I prefer to use in order to easily install my valve shields 22 or 122. As noted in FIG. 10, a latch support, such as pin 170, is affixed to one of the separable portions. A manually engageable latch 172 is moveably secured by the latch support 170. As noted from FIG. 13, a catch 174 is affixed to either the first 140 or second 142 separable portion, in the complementary separable portion. The catch 174 is adapted to lockingly engage the manually engageable latch 172, so as to secure the first 140 and second 142 separable portions one to the other.
Ideally, rather than the interlocking tab arrangement shown in FIGS. 4 and 5, I prefer to use an flexible hinge arrangement as noted in FIGS. 16 and 17. The hinge 180 has a first side 181 affixed to a first separable portion 140, and a second side 182 affixed to a second separable portion 142. The hinge may be any suitable flexible material such as a plastic strip 184, so that the first separable portion and the second separable portion are held together in a manner whereby the radiation shield 122 may be releasably moved between (i) a closed, working position, as seen in FIG. 10, and (ii) an open, installation position, as depicted in FIGS. 16 and 17. The interlocking of first portion 140 and second portion 142 is assisted by use of interfitting locating knobs 200 and detents 202, as seen throughout the FIGS. 9, 11, 16, and 17, for example. By use of the interfitting knobs 200 and detents 202, and the locking mechanism just illustrated, or a comparable arrangement, the separable shield portions can then be fastened together to secure the shield in place. Where appropriate, shield portions can be further secured in place by various means, such as, tape, nylon wire ties, or steel bands.
The configurations for shield 122 provided in FIGS. 10-17 are typical for shielding a 1/2 inch to 1 inch globe stop valve, which is commonly encountered in nuclear power plants.
Obviously, my radiation shields must be manufactured using an effective ionizing radiation attenuation substance for the body of the shields. I prefer lead, however, bismuth is also available and effective. These materials are preferred because they make for cost effective manufacture via casting methods. The radiation shield thickness is preferably provided in a wall thickness (T 1 or T 2 ) off at least about 1/2 inches in thickness in the radial direction, and is more preferably provided with a wall thickness of at least about 3/4 inches in thickness in the radial direction.
To avoid spread of lead contamination, my shields 22 or 122 are preferably coated with a special coating that is durable, easily decontaminated and acts as an effective protective barrier between the shield material and the valve, piping, or, other components. Specifically the most preferred coating comprises a thermoplastic, flexible, polyethylene co-polymer based powder coating which is applied by electrostatic deposition using a flame spray or fluidized bed process. Use of a Dupont "Flamecoat" process and polyethylene copolymer composition is one ideal way to accomplish the preferred coating, however, other flexible plastic coatings of suitable hardness and reliability will undoubtly be entirely serviceable. The coating powder is preferably of the following approximate effective composition:
Solids: 100%
VOC: 0
Specific Gravity: 0.934
Melting Point: 221° F.
Type: Ethylene methacrylic acid copolymer
The final installed coating preferably has the following physical characteristics and properties:
Impact Direct: 384 in.lbs.(on steel) ASTM D-2794
Impact Reverse: 384 in.lbs.(on steel) ASTM D-2794
Adhesion (steel): >1000 PSI ASTM D-454
Water Vapor Transmission: 0.003123 Perm inches at 15 mils thickness
My shields can be manufactured in various sizes and configurations so as to fit any desired valve, including the most common valves found in a nuclear power plant. Most of my shields are designed such that they can be used on most valves of similar type and size, regardless of manufacturer.
Radiation shields using my design can be custom manufactured to be installed around pipe, valves, conduit, or other structures from which radiation is being emitted. The exact design of the shielding will be based on the radiation source(s), the dose rate both (i) contact and (ii) general area type, the project shielding requirements (whether job specific or area dose rate reduction driven), the area configuration, including environmental conditions, the duration (temporary or permanent), and various engineering requirements, such as structure loading and seismic requirements.
In any event, it will thus be seen that the objects set forth above, including those made apparent from the proceeding description, are efficiently attained, and, since certain changes may be made in carrying out the construction of a radiation shielding apparatus to generally in the manner described, while still achieving the objectives as set forth herein. Therefore, it is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. For example, while I have set forth exemplary designs for an encapsulated lead radiation shield of half-round design, many other embodiments are also feasible to attain the result of the principles of the apparatus and via use of the methods disclosed herein. Therefore, it will be understood that the foregoing description of representative embodiments of the invention have been presented only for purposes of illustration and for providing an understanding of the invention, and it is not intended to be exhaustive or restrictive, or to limit the invention to the precise forms disclosed. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as expressed in the appended claims. As such, the claims are intended to cover the structures and methods described therein, and not only the equivalents or structural equivalents thereof, but also equivalent structures or methods. Thus, the scope of the invention, as indicated by the appended claims, is intended to include variations from the embodiments provided which are nevertheless described by the broad meaning and range properly afforded to the language of the claims, or to the equivalents thereof.
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A radiation shield for valves comprises separable portions of shielding composition, such as lead or bismuth, which are provided in hollow cylindrical half-round portions. The shield portions are interfitingly juxtaposed, and preferably interlocked, when installed in their operating, shielding position. The shields may be removably affixed to an existing valve or pipe. The shield has a hard shell coating, preferably of ethylene methacrylic acid copolymer, to prevent the shielding composition, e.g. lead, from contaminating the structure on which it is used. At least one locking or fastening latch mechanism is provided for securing the separable portions one to the other. Most preferably, a hinge mechanism is provided at one side of each of the of separable portions (separable half-rounds, in the ideal case), and the hinge mechanism also preferably serves to secure the pair of separable portions to each other, thus allowing rapid installation. The separable shield portions can then be fastened or locked together on side of the half-rounds opposite the hinge, so that the half-rounds cooperate to form a finished shield with full coverage around the pipe or valve being shielded.
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BACKGROUND OF THE INVENTION
[0001] The centrifuge is a time-honored method for increasing the density of particles. By effectively increasing the acceleration of gravity many fold, more dense materials and particles are readily pushed to the bottom of a test tube. This action discriminates only by the density of the particles. Yet it is effective for many suspensions of cells and other particles. For example, it is used for concentrating the density of red blood cells. Drawing off the fluids and lighter cells thus performs the crude sorting of cells in blood.
[0002] Many modern medical therapies would be possible if individual cells could be sorted by more discriminating methods. Tagging of cells with fluorescent markers and other methods make it possible to identify cells of interest. But the process of sorting the individual cells is limited to a time consuming process.
[0003] Prior art discloses suspending cells or particles in a stream of fluid. External sensing means can detect and type on the order of 10,000 cells per second. Breaking the stream into droplets captures individual cells in a droplet. A charge may be applied to the droplet. Electrostatic forces may be used to selectively deflect the droplets. Collecting the droplets in separate receptacles provides the desired sort.
[0004] Other discrimination methods may be employed such as particle size detection, optical absorption, and thermal conductivity etcetera.
DISCUSSION OF PRIOR ART
[0005] Microscopic vapor bubbles are commonly used as an actuator in ink jet printers such as U.S. Pat. No. 4,490,728 “Thermal ink jet printer”. These use the formation of a vapor bubble to expel ink from a small channel.
[0006] U.S. Pat. No. 6,062,681 “Bubble Valve and bubble valve-based pressure regulator” describes a channel with a bubble formed in it for pressure regulation.
[0007] This is an obstruction in the tube not a diverter from one tube to another.
[0008] Thomas K. Jun of UCLA uses a series of sequenced bubbles to pump fluids through a channel in his publication “Micro Bubble Pump”.
[0009] U.S. Pat. No. 5,878,527 “Thermal optical switches for light” uses vapor bubbles to form optical switches in fiber optic junctions.
SUMMARY OF THE INVENTION
[0010] The invention at hand is a microscopic valve. As a fluid flows through a “Y” junction, fluid is diverted to one leg or the other. This is done by momentarily closing the fluid channel of one leg or the other. The channel is closed by formation of a vapor bubble in the channel. Fluid and objects in the fluid are thus diverted to the opposite leg.
[0011] Particles of many types may be suspended in the flow. Detection means may be provided to determine a property of the fluids and particles flowing through. Detection means may be external or integrated into the substrate. Switching control may be internal or externally actuated. Switching may be in response to the properties detected.
[0012] The valves may be mass-produced in an array that processes particles through thousands of adjacent channels simultaneously. An array of such valves provides a simple integrated method for sorting cells. It is compact and scaleable to process a large volume of cells in parallel in a reasonable time.
[0013] Other applications include programmed mixing of solutions or gasses. Printing applications include mixing of ink. This can be used to alter dye or pigment density variations. Solutions and particles that are sorted can be arranged in desired orders.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows an oblique schematic view of a bubble actuated Y-valve with the top of the channels removed for clarity.
[0015] FIGS. 2 . 1 through FIG. 2 . 3 show a sequence of events used to direct a particle.
[0016] FIG. 3 . 1 through FIG. 3 . 4 show a sequence of events used to direct a particle with a generalized detector.
[0017] FIG. 4 . 1 through FIG. 4 . 5 show a sequence of events used to direct a particle with a specific sensor employing an integrated light source and light detector.
[0018] FIG. 5 . 1 and FIG. 5 . 2 show oblique views of two configurations of bubble actuated T-valves.
[0019] FIG. 6 shows an oblique view of a generalized X-valve.
[0020] FIG. 7 shows a plan view of an array of generalized X-valves.
[0021] FIG. 8 shows a plan view of an array of generalized T-valves.
DETAILED DESCRIPTION OF THE INVENTION
[0022] As depicted in FIG. 1 , a “Y” junction is formed by an entrance channel ( 1 ) and two output channels ( 2 a ) and ( 2 b ). The paths may be of the same cross-sectional area or differing cross-sectional area. A working fluid ( 4 ) is allowed or forced to flow from the entrance channel to the exit channels. The fluid is roughly divided between the two exit channels. Any particles ( 5 ) in the fluid will approach the junction ( 6 ). The particles will randomly go to one exit channel or the other exit channel. A vapor bubble ( 7 a ) is shown in the mouth of channel 2 a.
[0023] The fluid may be externally pumped into entrance channels or pulled from exit channels by methods common in the art. These include but are not limited to mechanical pumps, peristaltic pumps, gravity feed etcetera. Pumping means may be included on the substrate. Pumping means may be a sequence of bubbles. Pulses in the pumped stream may be synchronized with the valving functions.
[0024] FIG. 2 . 1 through FIG. 2 . 3 show the basic sequence of steps of a valve function. A working fluid ( 4 ) is pumped into the entrance channel ( 1 ). The working fluid may be water, aqueous solution, or any other fluid with a vapor point and viscosity suitable for the particular application. If a bubble ( 7 a ) is formed in the mouth of channel ( 2 a ) the flow will be directed to exit channel ( 2 b ). Alternately a bubble ( 7 b ) may be formed in channel ( 2 b ). This will direct the flow to exit channel ( 2 a ).
[0025] FIG. 2 . 1 shows a particle or particles ( 5 ) suspended and carried along within the working fluid ( 4 ). As the particle approaches the junction ( 6 ) a vapor bubble ( 7 a ) is formed in the mouth of output channel ( 2 a ) as shown in FIG. 2 . 2 . This restricts the flow through channel ( 2 a ). The fluid and particle are carried along into exit channel ( 2 b ) as shown in FIG. 2 . 3 . Alternately, a bubble may be formed in the mouth of channel ( 2 b ) directing the flow to exit channel ( 2 a ).
[0026] Bubbles may be formed by external means. This includes, but is not limited to, an external laser. The laser may be directed to form a bubble inside the working fluid. Alternately, energy dissipating features ( 3 a ) and ( 3 b ) may be included at the mouths of channel ( 2 a ) and ( 2 b ). Laser energy may be directed at these features. External light may be used to trigger a light activated switch. The substrate may be temperature controlled to a desired point near the boiling point of the working fluid ( 4 ). A super heated fluid can be triggered to nucleate by external energy source directed at the bubble generating site.
[0027] The energy dissipating features ( 3 a ) and ( 3 b ) may be thin film resistors. A current pulse may be passed through either of the thin film resistors. The heat dissipated in the resistor is coupled to the fluid in contact with the resistor. Vaporization of the thin layer occurs and a bubble is produced. The bubble may be sustained by energy dissipation. Once the heating ceases, the vapor quickly condenses and the bubble collapses. Various pulse widths and pulse shapes may be employed.
[0028] FIG. 3 . 1 through FIG. 3 . 4 show the basic operation of the valve used for sorting. FIG. 3 . 1 shows the working fluid ( 4 ) carrying along with it an occasional particle ( 5 ). The working fluid flows roughly equally through exit channels ( 2 a ) and ( 2 b ). In FIG. 3 . 2 the particle passes over detector ( 30 ). The detector may be built into the channel or be an external device. The detector may be suited to detect any desired property of the fluid or particle. If the property is found, an actuation means causes a bubble ( 3 a ) to be formed when the particle reaches the junction ( 6 ) as seen in FIG. 3 . 3 . This causes the flow and the particle to be diverted to exit channel ( 2 b ) as seen in FIG. 3 . 4 . Alternately, if the desired property is not found, a bubble could be formed at the mouth of exit channel ( 2 b ) causing the flow and the particle to de diverted to exit channel ( 2 a ).
[0029] FIG. 4 . 1 through FIG. 4 . 5 show one embodiment of a sensor in operation. This example, in no way restricts the generality of sequences that may be employed. In FIG. 4 . 1 a particle ( 5 ) is carried in the flow ( 4 ). The particle includes a fluorescent dye. In FIG. 4 . 2 the particle passes over a light emitting diode ( 40 ) formed in the entry channel ( 1 ). The photons excite the fluorescent dye on the particle ( 5 ). In FIG. 4 . 3 the working fluid ( 4 ) brings the particle past a light detector ( 41 ). In this case the rate of emitted photons is detected. As seen in FIG. 4 . 4 a logic and driver circuit ( 42 ) causes thin film resistor ( 3 a ) in exit channel ( 2 a ) to be energized. This causes the particle to pass to exit channel ( 2 b ) as seen in FIG. 4 . 5 .
[0030] Sensors may be made to detect a wide variety of properties as are known in the art. These include but are not limited to particle size, shadow cast, spectroscopy, emissivity, absorption, fluoresce, density, thermal conductivity, radioactivity, radioactive decay rate, etcetera. Chemical sensors can also detect toxins.
[0031] Radioactive particles are also readily detected. Particles may be irradiated and be rendered temporarily radioactive. The amount of radiation is readily detected and can be used as a criterion for sorting. The time decay of the radioactivity can also be used as an indicator. If the radiological properties of the particles in a suspension are cataloged, then the sorting can be used to identify the quantity of each constituent in the suspension.
[0032] Thermal properties can be exploited also. Heat pulses in the flow may be used to track the velocity of the fluid. Heat decay rates can be detected and used for categorizing materials.
[0033] The detector sites can also be used as chemistry sites. External means or catalysts at the site can cause chemical reactions to occur. The reactants may be detected. The bubble or bubbles can be used to delay the fluid flow to allow the needed time for the chemical reaction or time for detection.
[0034] Detector sites may be used to trigger a bubble while a strand is traversing a bubble generation site. The bubble formation may cleave the strand. Strands may be directed by subsequent channels and valves to be reconstructed at later sites.
[0035] Other valve configurations are possible. A “T” shaped junction can be employed. Without loss of generality, two examples are shown in FIG. 5 . 1 and FIG. 5 . 2 .
[0036] A natural extension of this sorting process is to make the sorting decisions in a widely parallel array. While this is possible with Y-valves or T-valves, these configurations lead to ever increasing density of channels. A hexagonal array eliminates this problem but is not favorable for production in silicon.
[0037] As seen in FIG. 6 another useful configuration is an “X” or “+”. Such an X-valve has two entrance channels ( 1 a ) and ( 1 b ) which feed to two exit channels ( 2 a ) and ( 2 b ). Sensors may be disposed at one or both inputs. Bubble sites may be in one or both of the exit channels. X-valves more readily allow the concatenation of valves. Channels can be readily fabricated using an-isotropic etching of silicon wafers.
[0038] FIG. 7 shows a schematic view of a sequence of X-valves arranged in parallel and series. A multiplicity of entrances ( 4 a ) are generally disposed on the top edge of each junction ( 6 ). A multiplicity of entrances ( 4 b ) are generally disposed on the left of each junction. The exits ( 2 a ) and ( 2 b ) are generally disposed on the right and bottom of each junction respectively. Collectively, the array exits are to the right and bottom.
[0039] FIG. 8 shows a schematic view of a sequence of T-valves arranged in parallel offset rows. A multiplicity of entrances ( 4 ) are generally disposed on the top edge of the array. The exits ( 2 a ) and ( 2 b ) are disposed on the right and left of each junction ( 6 ). Collective exits are disposed at the bottom and or sides of the arrays. This arrangement has the additional benefit of one sensor group per junction.
[0040] As in earlier examples, discriminating sensors and bubble generating sites are disposed at many or all of the intersections. Sensors may be nominally identical. Sensors may have one variety in one direction and a second variety in the other direction. The sensors may have a wide variety throughout the structure.
[0041] Velocity of working fluid can be monitored and adjusted by the actuation of bubbles within channels.
[0042] Sensors do not need to be very efficient. The redundancy of multiple detectors gives the overall apparatus many chances to make decisions and correct errors in decisions.
[0043] The discrimination function may be achieved with external sensors. A natural choice is to use a CCD camera that can simultaneously visualize a large number of junctions. This would require communicating decisions to each of the bubble forming regions. This may be done through optical excitation of the bubbles through photo detectors. Alternately, control signals could be directed in to each of the resistors. Driver circuitry may be centralized or distributed.
[0044] An alternative method would be to do all of the sensing, discrimination, and driving locally at each junction. A data channel can be routed to each node for control functions. A data channel can also be provided to communicate out the details of the sort provided or the aggregate of the sort accomplished. Logic circuitry may also be centralized on the substrate.
[0045] Virtual walls can be formed by a series of bubbles. This greatly reduces the need for wall structures and the need to align wall structures with the structures on the substrate. If bubbles are generated by an externally focused laser or focused sound, particles could be deflected within a thick layer of working fluid.
[0046] Sorting can be arranged in a wide variety of configurations. These include but are not limited to the examples cited herein. The concentration of a population can be increased. One population can be separated from another. A continuum of properties can be sorted for presenting a distribution at the arrays of exit channels. A detailed sorting can be used to arrange components for chemical assembly at the exit ports.
[0047] The working fluid can be arranged in short or long segments separated by gas. So a sorting array can be used to move and direct fluids or gas products. Elastomeric layers can be used to isolate the working fluid from the fluid or gas being transported.
[0048] Particles, fluids and gasses can me manipulated by the switches to reaction sites where chemistry can be directed. Resulting components can then be detected, sorted, and or directed for further processing. Ink can be directed by bubble valves. This may be used to mix incoming colors and color densities of ink for subsequent delivery to ink jet nozzles.
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A method and apparatus are presented for a microscopic valve. The valve is electronically activated. Sensors for detecting objects in the flow may be external or formed in the channels of the valve. Many valves can be formed in parallel and in sequence on a single substrate. Multiple channels may feed each junction. Closure of the valve is accomplished by the formation of a vapor bubble or bubbles. Virtual walls may be formed by a sequence of bubbles. Logic and driver circuitry for producing bubbles may be external or included in the substrate. Such an array is ideally suited for sorting cells. Other materials in a suspension may also be sorted by a variety of criteria. A multi lumen output can produce a continuous distribution of cells or particles thus sorted.
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This application is a continuation-in-part of Ser. No. 013,279, filed Feb. 21, 1979, now abandoned which is a continuation of Ser. No. 566,996, filed Apr. 10, 1975 now abandoned.
RELATED APPLICATION
The invention hereof is related to Applicants' copending application, Ser. No. 401,370, filed Sept. 27, 1973, entitled "METHOD OF BONDING SOLID LIGNOCELLULOSIC MATERIAL, AND RESULTING PRODUCT", now U.S. Pat. No. 4,007,312, dated Feb. 8, 1977, but is specific to defiberized lignocellulosic material for the manufacture of paper or paper like products in which enhanced interfiber bonding is effected in constradistinction to surface to surface interface bonding of solid wood.
BACKGROUND OF THE INVENTION
Bonding of lignocellulosic fiber materials, such as wood fiber, is widely used commercially as for example in the manufacture of paper or fiber products. In present commercial bonding procedures, bonding among the fibers is based primarily on physical forces created by the large surface of finely interlocked cellulose fibers. For increasing the bonding strength of such product, one may add to the pulp, before mat or sheet formation, sizing substances such as starch or resins as adhesives. Strength increase by such procedure is only moderate, and moreover the use thereof increases costs. Strength may also be increased by formation (fibrillation) of longer and more refined fibers. This involves, however, more complicated and costly chemical pulping procedures, and results in lower yield, of about 45% in the Kraft process, compared to 95% in mechanical pulping.
SUMMARY AND OBJECTS OF THE INVENTION
In the invention hereof, less expensive sources of lignocellulosic fibers are rendered available for the production of paper or paper like products, which provide physical properties comparable to more expensive fiber sources. Thus, high lignin content mechanical pulp (ground wood), semi-mechanical or semi-chemical pulp provide sources for the production of products of increased strength, such as liner board or other flexible paper, which could not normally be obtained otherwise. Such objective is achieved by increasing the interfiber bonding strength among the fibers, by thoroughly dispersing throughout a mat of the fibers, an oxidizing agent of a certain class which results in formation of interfiber chemical linkages effected by oxidation upon application of heat.
Ground wood, which is now widely employed as a source for newsprint or other high lignin content fibers, can by the invention hereof be employed for the manufacture of much stronger flexible sheets not heretofore obtainable from ground wood, such as liner board used in the manufacture of corrugated paper and cartons. Ground wood is mechanically ground in the presence of water, and is known as mechanical pulp. Substantially no lignin is removed by such mechanical treatment.
Although the invention hereof is particularly applicable to ground wood as it enables an inexpensive source of fiber to be used for paper products requiring strength properties not heretofore obtainable from ground wood, it may be employed with other sources of defiberized lignocellulosic material wherein at least some of the ligning is present such as semi-chemical and semi-mechanical pulps, which normally form weaker paper mats than fully delignified lignocellulosic material. In this connection, to obtain the oxidative bonding reaction, at least some lignin should remain in the defiberized material, or lignin like material, such as phenolics added thereto.
The chemical reactions involved in the process hereof are not fully understood. Wood is a high-polymeric substance composed of three classes of materials--carbohydrates (primarily cellulose), lignin and extractives. While cellulose is a polysaccharide built up of glucose units, lignin appears to be a polymeric phenolic material, the structure of which is still not fully understood. Not much is known about the bond between the carbohydrates and lignin, although, generally speaking, lignin seems to function as a binder for cellulose microfibrils. The function of extractives appears to be manifold; their disease protective function is probably the most important.
In oxidation of lignocellulosic materials several reaction systems may be involved at the same time. Based on the present day chemical knowledge, it can be assumed that the oxidation of phenolic units contained in lignin structure is either the main or at least one of the main reactions leading to self bonding of lignocellulosic materials. In this case the intermediate formation of free radicals is likely to take place, coupling under the formation of lignin-to-lignin linkages. It cannot be excluded, however, that to some extend polysaccharide-to-polysaccharide and lignin-to-polysaccharide bonding also takes place during this oxidation.
In effecting the oxidation reaction, a mat of the defiberized material is provided in which an oxidant is thoroughly dispersed uniformly therethrough. The mat is formed into a sheet under pressure and heat for a time sufficient to effect the oxidative reaction. In this connection, the oxidizing agent may also be employed with a promoter to promote the oxidative bonding.
The invention hereof may readily be performed on a paper making machine wherein a paper mat is formed in the conventional manner. The mat is then sprayed or roller coated with the oxidant in a liquid carrier which wets the mat, and with a catalyst to promote the reaction. They may both be contained in the same carrier or applied separately to the sheet in the machine as will be discussed more fully hereinafter.
From the preceding it is seen that the invention has as its objects, among others, the provision of an improved method of effecting increased interfiber bonding among fibers of defiberized lignocellulosic material by effecting an oxidative reaction among the fibers, which method is simple to perform and renders available less expensive sources of pulp for the manufacture of paper or paperboard sheets requiring strength, and which is economical and simple to perform.
Other objects will become apparent from the following more detailed description, and accompanying drawing, in which:
The single FIG. 1 is a schematic side elevational view of a conventional Fourdrinier paper making machine in which the invention hereof may be performed in various ways; parts being broken away to shorten the view.
PRIOR ART
The patent to Heritage U.S. Pat. No. 2,125,634, dated Aug. 2, 1938, discloses bleaching of paper pulp in a paper making machine by applying hydrogen peroxide to the wet or partially wet mat in minute concentrations in the presence of an alkali such as sodium silicate, at a point ahead of or in advance of the dry end of the dryer, solely to bleach the sheet or pulp. However, it has been found pursuant to this invention that hydrogen peroxide will effect the oxidative bonding reaction better if a catalyst is provided. It is believed that such catalyst (examples of which are given below) modifies the hydrogen peroxide by decomposing it under heat and pressure to free radicals instead of to oxygen and water. Transition metals and many other inorganic and organic substances can effect such peroxide decomposition. Moreover, the pH of the hydrogen peroxide solution should be below pH 7, and the concentration of the hydrogen peroxide in the carrier should be above 1% to be effective, and desirably above 5%, and may be as high as 50%.
DETAILED DESCRIPTION
In performing the method hereof, a lignocellulosic mat of for example ground wood fiber is formed in the usual manner as a continuous sheet. After the sheet is formed, it is wetted with a liquid carrier containing an oxidizing agent selected as described below and which penetrates the sheet thoroughly and covers the surfaces of the individual fibers. The wetting may be effected in any suitable manner such as by spraying the liquid carrier containing oxidant over a surface of the sheet or by roller coating the same on such surface. Where a catalyst is employed it is also uniformly dispersed throughout the sheet to promote oxidation by the oxidant. Various procedures of oxidant application to the sheet may be employed, such as:
1. The lignocellulosic fiber sheet may be simply wetted with a liquid carrier containing an oxidant of the type effective without a catalyst discussed hereinafter, or with a mixture of oxidant and catalyst, followed by application of heat and pressure. The effectiveness varies depending upon factors such as type of oxidant, temperature and time. Hydrogen peroxide used with a catalyst, such as a transition metal compound, e.g. zirconium tetrachloride, ferric chloride or cupric chloride can be effectively employed in this manner of application.
2. In many instances a higher level of interfiber bonding may be obtained if the lignocellulosic sheet is first wetted with the oxidant thoroughly penetrating the sheet followed by treatment with a liquid carrier containing a catalyst. Subsequent wetting with a liquid carrier containing hydrogen peroxide forms a Fenton reagent with the transition metal catalyst, which is a very effective oxidizing agent for the lignocellulosic fibers. Pressing under an elevated temperature is then effected.
3. Another mode of application is first to wet the sheet with a liquid carrier containing a peroxide such as a peracid to incorporate peroxy groups into the lignocellulosic material. After such incorporation, a liquid carrier containing a transition metal catalyst is added to the material, followed by application of pressure at an elevated temperature to form the flexible paper sheet.
4. In some commercial processes which are known as dry or semi-dry processes used in the production of fiberboards or hardboards, the dry or semi-dry pulp is formed as a relatively thick mat which may be 2 or 3 inches in thickness, and then compacted into a relatively thin rigid board. Because of the initial thickness of such mat, it may be difficult to obtain uniform penetration or dispersion throughout the mat by spraying or roller spreading the carrier containing the desired oxidizing agent on the mat surface.
To insure such uniform penetration the oxidizing agent, if used alone, and the catalyst if employed with the oxidant have to be thoroughly intermixed with fiber. If the catalyst does not react with the oxidant at ambient temperature, they may be both included in the same liquid carrier. However some catalysts may react with the oxidant at ambient temperature, such as hydrogen peroxide and ferrous sulfate. In such event to produce the reaction initially in the fiber, the catalyst and the oxidant are applied separately in two steps. For example, the carrier and oxidant may be applied first, and then the carrier and catalyst, or vice versa. Also, an oxidizing agent may be mixed with one-half of the material for formation of the mat, and a transition metal catalyst thoroughly mixed with the other half, followed by mixing of the two parts together which results in uniform incorporation of oxidant and catalyst in the mat. The mat is then compacted under pressure and heat to form the desired product.
From the preceding it is seen that particular procedures for performing the method hereof may vary widely. In the manufacture of flexible paper and related products such as flexible liner board, the method hereof can be performed readily on a conventional paper making machine. It is only necessary to spray or otherwise apply to the fiber sheets in the machine a liquid carrier containing oxidant, catalyst, or oxidant and catalyst as the case may be, in the manner outlined above. The liquid carrier penetrates the sheet thoroughly. Also, the agents might be included in the water slurry prior to dehydration of the sheet on the paper making machine.
There are a number of types of oxidizing agents (and of catalysts where they are used) that may be employed as will be listed subsequently. It is only necessary, irrespective of the system of oxidant or of catalyst used, to effect the oxidative bonding reaction among the fibers of the lignocellulosic material at an elevated temperature and for a time sufficient to effect such interfiber bonding. The oxidative reaction is effected primarily by heat but it is desirably conducted under pressure as well as heat in order to effect bonding between fibers, which are kept in close contact by the pressure such as by plates in a conventional press or by the pressure effected by calendar rolls in a paper making machine. In this connection, relatively dry paper already formed may be wetted in the manner related with oxidant or oxidant and catalyst, and when heated increased oxidative bonding will occur.
The temperature and time for obtaining the oxidative bonding reaction among the fibers will vary depending upon the oxidants and the character of the fibrous material. As usual, the lower the temperature the longer the reacting time and vice versa. The reacting temperature should not exceed the temperature at which charring of the lignocellulosic material will occur. Also, the pressure applied should not exceed that at which the lignocellulosic material is crushed.
With higher amounts of some oxidants such as hydrogen peroxide, and compatible catalysts the pressing or reacting temperature may be as low as ambient. A suitable temperature range is between 20° C. and 250° C. with a reaction time of 0.1 to 15.0 minutes at a pressure of between atmospheric and 950 psi.
As a solvent or liquid carrier for the oxidant, any liquid may be employed which does not react with the wood such as water or alcohol. The solvent readily escapes as vapor during the pressing and drying of the mat.
The amount and concentration of oxidant solution will also vary widely depending upon the chemical character of the oxidant, the type of lignocellulosic material, and reaction conditions. In general, an amount of carrier solution (which need not be a true solution but which may be a suspension) is used which will provide from 0.5 to 6.0% of oxidant based on the dry weight of the lignocellulosic material but this range is not critical as even small amounts of reagent are effective. Large amounts serve no useful purpose. For any given oxidant one can readily determine the amounts and conditions of treatment which will produce optimum oxidative bonding.
As noted above, a variety of oxidants may be used for the purposes of this invention to effect the interfiber bonding of defiberized lignocellulosic material by oxidative bonding. Some of these oxidants are effective alone without catalysts while others require or benefit by a catalyst in conjunction therewith to promote the oxidative bonding.
The oxidants that are used are per compounds, nitrates and chlorates, examples of which are as follows:
Per compounds: Hydrogen peroxide, per acids such as peracetic acid, persulfuric acid, ozonides, acylperoxides, such as benzoylperoxide, di- and monoalkylperoxides, such as ethylperoxide, and other compounds with O-O linkage.
Nitrates: Sodium nitrate, ammonium nitrate, potassium nitrate, barium nitrate, lead nitrate, zinc nitrate.
Chlorates: Sodium chlorate, ammonium chlorate, potassium chlorate, barium chlorate.
Where a per compound is used, it is used at an acid pH, e.g. pH=3 to 6 and it is preferably, although not necessarily used with a catalyst. Such catalysts as transition metal compounds, e.g. zirconium tetrachloride, ferric chloride and cupric chloride may be used, also ferrous, manganese, chromium, lead, copper and cobalt salts. Nitrates and chlorates generally require no catalyst and may be used at acid, neutral or alkaline pH.
Catalysts can be applied in the liquid carrier mixed with the oxidant or separately. Catalysts also include various organic and inorganic reducing agents such as hydroquinone, pyrogallol, tannins, hydrazine and bisulfites. The amount of catalyst used is relatively small compared to the amount of oxidant and usually will vary from 0.01% to 1.0% by weight of the oxidant, but this rrange is not critical.
The following are typical examples of hand prepared samples prepared by conventional laboratory procedures demonstrating the principles of the instant invention:
EXAMPLE 1
A mat of Western hemlock ground wood fibers about 1 foot square, was formed on a sieve screen of about 120 mesh from a water slurry of about 4% consistency. It was pressed between such screen and another similar sieve screen to a thickness of about 0.1 in., to partially dehydrate the resultant mat to a consistency of about 40%, and the mat while still wet was then sprayed with a water carrier containing about 15% by weight of hyrogen peroxide and about 0.75% by weight of zirconium tetrachloride; the total amount of carrier, oxidant and catalyst being about 6.5% by weight of the dry weight of fibers. After allowing the carrier and its contents to penetrate the mat which took about 1 minute, the mat was promptly pressed between two 120 mesh sieve screens at a temperature of about 150° C. and pressure of about 700 lbs. per sq. inch (psi) for about 2 minutes to thus form a flexible paper sheet suitable for use as liner board. The physical properties of this sheet and those of following Examples 2 and 3 are noted in subsequent Table I which also includes properties of control samples which were made in the same way as in the examples but without oxidant and catalyst.
In this example, it will be noted that the oxidants and the catalyst were both applied from the same water carrier.
EXAMPLE 2
A mat of one foot square was formed of Western hemlock ground wood fiber from a water slurry containing about 5% by weight of the ground wood and 0.125% of sodium hypochlorite as a preoxidant thoroughly dispersed in the wood fiber. It was pressed as in Example 1 to partially dehydrate the resultant mat to a consistency of about 40%, and was then sprayed with a 2.5% water solution of ferrous sulfate catalyst in the amount of about 5% solution to the weight of dry fibers. After the solution was allowed to penetrate the mat as in Example 1, it was sprayed with a 20% water solution of hydrogen peroxide in the amount of about 5% of solution to the weight of dry fiber, and was then pressed between two sieve screens as in Example 1 at a temperature of about 150° C. and pressure of 700 psi for two minutes which resulted in a flexible paper sheet.
In this example, the impregnation with hypochlorite as a preoxidant, is followed by sequential catalyst and oxidant addition.
EXAMPLE 3
A mat one foot square was formed as in Example 1 from a water slurry of Western ground wood fiber. After draining and partial dehydrating by pressing between two sieve screens, the mat was sprayed with 7.5% water solution of persulfuric acid in the amount of 10% of the solution to the weight of dry fiber. After allowing the penetration to occur (about 2 minutes) the sheet was sprayed with 2.5% water solution of ferrous sulfate in the amount of 10% solution to the weight of dry fiber, and was pressed as in Examples 1 and 2 at a temperature at about 150° C. and pressure of 700 psi for about two minutes. This example illustrates sequential addition of oxidant and catalyst.
The physical properties of the paper sheet materials produced under conditions of Examples 1 through 3 are noted in the following Table I, which as noted above also includes the properties of control samples which were treated in the same way as in Examples 1 through 3 but without the oxidizing agents.
TABLE I______________________________________ Tensile strength psi Thickness Thickness Density 24 hrs. swellingExample in. gr/ft.sup.2 dry soaked %______________________________________1 0.023 55 1987 512 392 0.025 54 2649 663 343 0.024 56 2505 495 26Control 0.024 57 2037 282 51______________________________________
The data set forth in the Table for each example is an average of 10 tests. From the Table, it will be noted that the thickness and density resulting from all tests are substantially the same. The dry tensile strength data of Examples 2 and 3 evidence the efficaciousness of the oxidative interfiber bonding achieved under the conditions described in these examples.
It is noteworthy that the tensile strengths of the sheets after they had been soaked in water for 24 hours establish the marked improvement in wet strength of Examples 1 through 3 compared to the control. Also, it will be observed that the control had a much higher percent of thickness swelling than the sheets of Examples 1 through 3, which evidences the bonding strength obtained by the method of this invention. The less the swelling, the higher the bonding strength, or decrease in hygroscopicity.
EXAMPLE 4
A rigid hard board suitable as a building board panel was produced in the following manner. Western hemlock ground wood fibers were sprayed with a 1.25% water solution of sodium hypochlorite followed by spraying with a 1.25% water solution of ferrous sulfate both in the amount of about 100% solution to the weight of dry fibers. After thorough mixing, a mat was formed from a water slurry containing about 5% by weight of treated fibers. After draining and partial dehydration by pressing the sheet between two sieve screens as in the previous examples, the sheet was sprayed with a 20% water solution of hydrogen peroxide in the amount of 10% to dry weight of fibers. After such treatment, the sheet was pressed between two sieve screens at a temperature of 150° C. and pressure of about 850 psi for five minutes to produce hardboard of 0.117 in thickness and 1.055 specific gravity. Table II, below, depicts the physical data obtained by an average of ten tests on samples produced by Example 4, compared to a control which was not treated with oxidizing agents, also an average of 10 tests.
TABLE II______________________________________ Tensile strength psi Thickness Thickness Specific 24 hrs. swellingExample in. gravity dry soaked %______________________________________4 0.117 1.055 4322 1424 26.6Control 0.123 1.034 4103 667 52.2______________________________________
EXAMPLE 5
This example is one wherein hard board is produced from a relatively thick mat which is compacted to a relatively thin rigid board. One part of ground wood fiber particles was sprayed with a 1.25% water solution of sodium hypochlorite as a preoxidizing agent followed by spraying with a 1.25% water solution of ferrous sulfate both in the amount of about 10% by weight of the fiber on a dry basis. The other part was sprayed with a 20% water solution of hydrogen peroxide also in the amount of 10% by weight of the dry weight of fibers. The thoroughly wet sprayed parts were then thoroughly mixed together; and a sheet of about a thickness of about 2 inches was formed and then pressed between sieve screens of about 120 mesh to dehydrate the mat to a water consistency of about 40%. The mat was conveyed on the screens into a press in the usual manner, and the mat was compressed to a thickness of about 1/8 inch under a temperature of about 150° C. and pressure of about 850 psi for about 2 minutes which resulted in a rigid hard board suitable for building purposes.
Thickness of the board was 0.120 in.; specific gravity 1.071; dry tensile strength 4,416 psi; tensile strength after 24 hrs. soaking in water 1,519 psi, and thickness swelling 24.4%.
EXAMPLE 6
Fiber made by pressure refining of hardwood chips was sprayed by a water solution of pH 7.5 containing 20% by weight of potassium nitrate. Ten percent of the solution by weight to oven dry fiber was sprayed during substantial mixing of the fiber to get a good distribution of the solution in fiber. After drying the fiber to about 6 to 9% moisture content a fiber mat was formed by hand which was then deposited between two smooth metalic plates into a press and pressed to 1/4 inch thick hardboard at 240° C. for 3 minutes at 500 psi pressure. This produced hardboard which had a modulus of rupture of 5,100 psi, an internal bond of 220 psi and a specific gravity of 1.015.
EXAMPLE 7
Fiber made by pressure refining of hardwood chips was sprayed by water solution of 9.0 pH containing 5% of sodium nitrate and 30% of sodium carbonate. Twenty percent of the solution by weight to oven dry wood was sprayed followed by drying the fiber to 6-9% moisture content and forming a fiber mat which was then deposited between two metallic plates in a press and pressed to hardboard. Press platens were at 240° C. and the hardboard was pressed for 3 minutes at 500 psi pressure. The boards had a specific gravity of 0.967, a modulus of rupture of 5,200 psi and an internal bond of 196 psi.
EXAMPLE 8
Fiber made by pressure refining of hardwood chips was sprayed by a water solution containing 11% by weight of sodium chlorate. Eighteen percent of this solution by weight to oven dry fiber was sprayed during substantial mixing of the fiber to get a good distribution of the solution in the fiber which was then formed into a mat. Such mats having about 17% moisture were then deposited between two metallic plates in a press and pressed at 240° C. press platen temperature and 500-180 psi pressure to 1/4 inch thick boards for 3 minutes. The resulting boards had a specific gravity of 0.999, a modulus of rupture of 4,900 psi, an internal bond of 350 psi and a thickness swelling after 1 hour in boiling water of 32%.
EXAMPLE 9
Fiber made by pressure refining of hardwood chips was sprayed by a water solution containing 8.42% of sodium chlorate, 20% of sodium carbonate (soda ash), all by weight. Twenty-four percent based on dry fiber of this solution was sprayed during substantial mixing of the fiber to get a good distribution of the solution in the fiber. Fiber mats were hand formed from such fiber having about 17% of moisture which were then deposited in a press between two metallic plates. Press platens were at 240° C. temperature and hardboards were pressed for about 3 minutes at 500-180 psi pressure. This produced 1/4 inch thick hardboards having a modulus of rupture of 7,000 psi, an internal bond of about 500 psi and a thickness swelling after 1 hour in boiling water of 33%. Specific gravity was 1.02.
As was noted above, the method hereof is particularly adapted for performance in a paper making machine. Referring to FIG. 1, a conventional type of Fourdrinier machine is schematically illustrated. It comprises headbox 2 from which a slurry of defiberized material, such as ground wood, is discharged onto a Fourdrinier wire or table 3 on which the mat is initially formed. From wire 3, the wet web of paper is continuously discharged into press section 4 through which it is continuously conveyed through press rolls 6, and wherein the moisture content is reduced by mechanical pressure effected by the rolls. The thus partially dehydrated sheet is continuously conveyed through dryer section 7 which removes remaining moisture from the sheet by means of heat and vapor transfer; the dryer section comprising a large number of heated drying rolls 8. From the dryer section, the now substantially dehydrated sheet passes through calender stack 9 comprising a series of smooth surfaced, heated calender rolls 11 which control the thickness of the sheet, its smoothness and other characteristics. The calendered sheet is then wound into a roll 12.
As previously related, the oxidant or oxidant and catalyst may be applied to the defibered lignocellulosic material in various ways rendering the method hereof very versatile. For example, with reference to paper making machine application, if only an oxidant or oxidant and catalyst is applied, the liquid carrier containing the oxidant or mixture of oxidant and catalyst may be suitably added at positions indicated at A, B or C in the machine, which results in penetration of the oxidant, or catalyst and oxidant, into the sheet.
Where mild preoxidation of the sheet is desirable, a small amount of the preoxidizing agent, such as sodium hypochlorite, may be added in the slurry in the headbox, or at position A. The carrier containing the transition metal catalyst may be added midway in the dryer section indicated at position B, and the carrier containing hydrogen peroxide oxidant at position C just ahead of calender stack or rolls.
Where the sheet is to be treated with a peracid or peroxide, it may be added at position D, just before the press section; and the carrier containing a transition metal catalyst at position B or C. Both surfaces or only one surface of the sheet may be wetted. Also, a catalyst solution may be applied to one surface and the oxidant solution to the other surface of the sheet as long as they are thoroughly intermixed in the mat.
From the preceding, it is seen that the procedure comprises a two step process, namely (a) treatment of the defibered lignocellulosic material with oxidant or oxidant and catalyst before pressing, namely before bringing the fiber surfaces into sufficient contact, and (b) effecting the bond formation reaction by temperature increase, and desirably under pressure.
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Defiberized lignocellulosic material, such as wood, is treated with a liquid carrier containing an oxidizing agent (a per compound, a chlorate or a nitrate), and the wet mat thereof is subjected to pressure, and to heat for a sufficient period of time to cause an oxidative reaction among the fibers resulting in a strong interfiber bond. Where the oxidizing agent is a per compound, the pH of the mixture or lignocellulosic material and per compound is less than 7. Catalysts or other reaction modifying agents are employed if needed. By virtue of the enhanced interfiber bonding effect, paper sheets, such as liner board, which are usually formed of delignified cellulosic material, the fibers of which are highly refined, can be formed totally or partially of less expensive sources of material such as ground wood, semi-chemical or semi-mechanical lignocellulosic pulps without sacrifice of strength.
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The present application is a continuation of application Ser. No. 07/890,265, filed May 29, 1992, now U.S. Pat. No. 5,293,749, which is a divisional of (1) application Ser. No. 07/722,547, filed Jun. 26, 1991, now U.S. Pat. No. 5,154,063, (2) of application Ser. No. 07/721,816, filed Jun. 26, 1991, now U.S. Pat. No. 5,144,805, and (3) of application Ser. No. 07/721,135, filed Jun. 26, 1991, now U.S. Pat. No. 5,144,810, each of which is, in turn, a divisional of application Ser. No. 07/430,582, filed Nov. 1, 1989, now U.S. Pat. No. 5,092,130.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multi-stage cold accumulation type refrigerator and a cooling device utilizing the same.
2. Discussion of the Invention
FIG. 29 shows a conventional three-stage GM (Gifford-McMahon) refrigerator as a multi-stage cold accumulation type refrigerator as disclosed in Advances in Cryogenic Engineering Vol. 15, p428, 1969, for example. The refrigerator includes a third cold accumulator 1 having a cold accumulating member formed of lead balls, a second cold accumulator 2 having a cold accumulating member formed of lead balls, a first cold accumulator 3 having a cold accumulating member formed of copper wire net, a third displacer 4, a second displacer 5, a first displacer 6, a third seal 7 for preventing leakage of a helium gas 16 from an outer periphery of the third displacer 4, a second seal 8 for preventing leakage of the helium gas 16 from an outer periphery of the second displacer 5, a first seal 9 for preventing leakage of the helium gas 16 from an outer periphery of the first displacer 6, a three-stepped cylinder 10 formed from a honing pipe, a suction valve 11 for inducing the helium gas 16 compressed by a helium compressor 13, an exhaust valve 12 for exhausting the helium gas 16, a driving motor 15, a driving mechanism 14 for converting rotation of the driving motor 15 into a linear motion and operating the suction valve 11 and the exhaust valve 12 in synchronism with the linear motion, third, second and first expansion chambers 17, 18 and 19 for expanding the helium gas 16, a third thermal stage 20 for transmitting cold generated in the third expansion chamber 17 to a body to be cooled (not shown), a second thermal stage 21 for transmitting cold generated in the second expansion chamber 18 to the body, and a first thermal stage 22 for transmitting cold generated in the first expansion chamber 19 to the body.
The operation of the above refrigerator will now be described. FIG. 30 is a P-V diagram in the expansion chambers 17 to 19, wherein an axis of ordinate represents a pressure in the expansion chambers 17 to 19, and an axis of abscissa represents a volume of the expansion chambers 17 to 19. Under the condition as shown by (1), the displacers 4 to 6 are disposed as their uppermost positions, and the suction valve 11 is open, while the exhaust valve 12 is closed. Accordingly, the pressure in the expansion chambers 17 to 19 is a high pressure PH. When the condition is shifted from (1) to (2), the displacers 4 to 6 are lowered, and the helium gas 16 having a high pressure is induced through the cold accumulators 1 to 3 into the expansion chambers 17 to 19. During this operation, the valves 11 and 12 remain still. The helium gas 16 is cooled to predetermined temperatures by the cold accumulators 1 to 3. Under the condition at (2), the volume of each expansion chamber is maximum, and the suction valve 11 is closed, while the exhaust valve 12 is opened. At this time, the pressure of the helium gas 16 in each expansion chamber is reduced to generate cold, and the condition is shifted to (3). When the condition is shifted from (3) to (4), the displacers 4 to 6 are raised, and the helium gas 16 having a low pressure is exhausted. At this time, the helium gas 16 cools the cold accumulators 1 to 3, and the temperature of the helium gas 16 is increased. Then, the helium gas 16 is returned to the helium compressor 13. Under the condition at (4), the volume of each expansion chamber is minimum, and the exhaust valve 12 is closed, while the suction valve 11 is opened. As a result, the pressure in each expansion chamber is increased to restore the condition shown by (1).
In the multi-stage cold accumulation type refrigerator as mentioned above, the efficiency of the third cold accumulator is rapidly reduced, and temperature of 6.5K. or less can not be obtained because a specific heat of lead forming the cold accumulating member of the third cold accumulator is smaller temperature of 10K. or less, while a specific heat of helium gas is large.
Further, a generated refrigeration quantity becomes smaller than an indicated refrigeration quantity at a temperature of 4K. owing to a change in physical property of helium. Accordingly, there occurs a problem of heat generation due to sliding resistance of the seal.
Further, as the specific heat of the third heat stage becomes small at temperature of about 4K., temperature oscillation in a refrigeration cycle is increased to cause a reduction in efficiency.
If the cold accumulating member in the conventional multi-stage cold accumulation type refrigerator is formed of an alloy or compound containing a rare earth metal (which alloy or compound will be hereinafter referred to as a rare earth substance), fine powder of the cold accumulating member is generated by vibration during operation, and is deposited to the seal portions, causing a reduction in sealing effect and an increase in friction between each displacer and the cylinder.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a multi-stage cold accumulating type refrigerator which improves the efficiency, temperature stability and reliability, and also provide various cooling devices utilizing such a refrigerator.
According to a first aspect of the present invention, there is provided in a multi-stage cold accumulation type refrigerator including a compressor disposed at an ordinary temperature, a helium gas as a common operating fluid to be compressed by said compressor, and one or more expansion chambers and cold accumulators of different temperature levels; the improvement wherein a cold accumulating member of said cold accumulators is formed of an alloy or compound containing a rare earth metal.
According to a second aspect of the present invention, there is provided in a multi-stage cold accumulation type refrigerator including a compressor disposed at an ordinary temperature, a helium gas as a common operating fluid to be-compressed by said compressor, and one or more expansion chambers and cold accumulators of different temperature levels; the improvement wherein a cold accumulating member of said cold accumulators is formed of two or more kinds of substances according to a temperature region where a large specific heat is obtained, and GdRh is used for the cold accumulating member at a high temperature level, while Gd 0 .5 Er 0 .5 Rh is used for the cold accumulating member at a low temperature level, and a weight ratio of GdRh is set to 45-65%.
According to a third aspect of the present invention, there is provided in a multi-stage cold accumulation type refrigerator including a compressor disposed at an ordinary temperature, a helium gas as a common operating fluid to be compressed by said compressor, and one or more expansion chambers and cold accumulators of different temperature levels; the improvement comprising a seal for preventing leakage of said helium gas, wherein a heat generation quantity due to sliding resistance of said seal is set to be smaller than a theoretical generated refrigeration quantity to be obtained on the assumption of isothermal expansion in said expansion chambers.
According to a fourth aspect of the present invention, there is provided in a multi-stage cold accumulation type refrigerator including a compressor disposed at an ordinary temperature, a helium gas as a common operating fluid to be compressed by said compressor, and one or more expansion chambers and cold accumulators of different temperature levels; the improvement comprising a cylinder, a seal for preventing leakage of said helium gas, a thermal anchor mounted on an outer surface of said cylinder at a position where said seal is slid, said thermal anchor being formed of a good heat conductor and thermally connected to a high-temperature thermal stage so as to absorb heat generation due to sliding resistance of said seal.
According to a fifth aspect of the present invention, there is provided in a multi-stage cold accumulation type refrigerator including a compressor disposed at an ordinary temperature, a helium gas as a common operating fluid to be compressed by said compressor, and one or more expansion chambers and cold accumulators of different temperature levels; the improvement wherein a cold accumulating member formed of an alloy or compound containing a rate earth metal having a large specific heat at a temperature region of 10K. or less or a container for containing helium is mounted to an end of a cylinder, thermal stage or displacer disposed at said temperature region, so as to reduce a temperature change in a refrigeration cycle.
Other objects and features of the invention will be more fully understood from the following detailed description and appended claims when taken with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a vertical sectional view of a preferred embodiment of the three-stage GM refrigerator according to the present invention;
FIG. 2 is a characteristic graph of the specific heat of the cold accumulating member to be used in the refrigerator with respect to a temperature change;
FIG. 3 is a characteristic graph of the temperature of the third thermal stage in the refrigerator with respect to a change in ratio of GdRh;
FIG. 4 is a characteristic graph of the theoretical generated refrigeration quantity with respect to a temperature change;
FIGS. 5A and 5C are enlarged sectional views of different types of the seal portion in the refrigerator;
FIG. 5B is a cross section taken along the line A--A in FIG. 5A;
FIG. 6 is a characteristic graph of the temperature of the third thermal stage with respect to a change in surface roughness of the inner surface of the cylinder;
FIG. 7 is a schematic illustration of an experimental system in the preferred embodiment;
FIG. 8 is a characteristic graph of the refrigerating capacity with respect to a temperature change;
FIG. 9 is an enlarged sectional view of the trapping magnets for trapping fine powder of the cold accumulating member;
FIG. 10 is a schematic illustration of the three-stage GM refrigerator to be used in the present invention;
FIG. 11 is a characteristic graph of the refrigerating capacity of the refrigerator shown in
FIG. 10 with respect to a temperature change;
FIG. 12 is a schematic illustration of a preferred embodiment of the cryopump according to the present invention;
FIG. 13 is a view similar to FIG. 12, showing another preferred embodiment of the cryopump;
FIG. 14 is a sectional view of a preferred embodiment of the superconducting magnet cooling device according to the present invention;
FIGS. 15, 16 and 17 are views similar to FIG. 14, showing various modifications of the superconducting magnet cooling device;
FIG. 18 is a sectional view of a preferred embodiment of SQUID cooling device according to the present invention;
FIGS. 19 and 20 are views similar to FIG. 18, showing various modifications of the SQUID cooling device;
FIG. 21 is a sectional view of a preferred embodiment of the superconducting computer cooling device according to the present invention;
FIGS. 22 to 25 are views similar to FIG. 21, showing various modifications of the superconducting computer cooling device;
FIG. 26 is a sectional view of a preferred embodiment of the infrared telescope cooling device according to the present invention;
FIGS. 27 and 28 are views similar to FIG. 26, showing various modifications of the infrared telescope cooling device;
FIG. 29 is a vertical sectional view of the three-stage GM refrigerator in the prior art; and
FIG. 30 is a P-V diagram of a refrigeration cycle in the refrigerator shown in FIG. 29.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, the three-stage Gifford-McMahon cycle refrigerator (which will be hereinafter referred to as GM refrigerator) includes a low-temperature section 1 of a third cold accumulator, a high-temperature section 23 of the third cold accumulator, a thermal anchor 24 mounted on an outer surface of a cylinder 10 at a seal sliding portion, an internal uniform heating cold accumulating member 25 mounted on an end of a third displacer 4, an external uniform heating cold accumulating member 26 mounted to a third thermal stage 20, and a trapping magnet 27.
Referring to FIGS. 5A and 5C, reference numeral 28 denotes a tension ring of a piston ring 7a as a preferred embodiment of a third seal 7, and reference numeral 7b denotes a labyrinth seal as another preferred embodiment of the third seal 7.
Referring to FIG. 7, the experimental system includes a vacuum tank 29 for heat insulation, a helium conduit 30, a helium cylinder 31, a pressure reducing valve 32 for reducing a pressure of the helium gas from the helium cylinder 31, a manometer 33, a heater 34 mounted to a helium tank used as the external uniform heating cold accumulating member, a liquid helium 35, a temperature sensor 36 and a radiation shield 37.
Referring to FIG. 9, reference numerals 38, 39 and 40 denote a fine powder of the cold accumulating member, a trapping magnet II provided at an outlet of the cold accumulator, and a trapping magnet III provided at a center of the cold accumulator.
In the multi-stage cold accumulation type refrigerator as constructed above, the cold accumulating member of the low-temperature section 1 and the high-temperature section 23 of the third cold accumulator is formed of a rare earth substance having a large specific heat at low temperature of 10K. or less, so as to improve the efficiency as the cold accumulator. FIG. 2 shows specific heats per unit volume of lead, rare earth substances (e.g. GdRh and Gd 0 .5 Er 0 .5 Rh) and 20 bar helium. In the refrigerator shown in FIG. 1, the helium gas to 40K. in a first cold accumulator 3, and is then refrigerated to 11K. in a second cold accumulator 2, and is then further refrigerated in the third cold accumulator 1 to be introduced into a third expansion chamber 17. If lead is used for the cold accumulating member of the third cold accumulator 1, the helium gas is not sufficiently refrigerated since the specific heat of lead is smaller than that of the helium gas as apparent from FIG. 2. Accordingly, temperature in the third expansion chamber 17 is increased to generate a loss. In contrast, if GdRh is used for the cold accumulating member, the loss can be reduced to thereby lower an attainable temperature since the specific heat of GdRh is larger than that of lead as apparent from FIG. 2.
As the result of a comparative test using lead and GdRh for the cold accumulating member of the third cold accumulator 1, the attainable temperature in the case of lead was 6.5K., while it was 5.5K. in the case of GdRh. As apparent from FIG. 2, the specific heat of GdRh is relatively large in the range of 20K. to 7.5K., while the specific heat of Gd 0 .5 Er 0 .5 Rh is relatively large in the range of 7.5K. or less. Accordingly, the efficiency can be more improved by using GdRh for the high-temperature section 23 of the third cold accumulator and using Gd 0 .5 Er 0 .5 Rh for the low-temperature section 1 of the third cold accumulator. FIG. 3 shows a change in the attainable temperature with a change in ratio between Gd 0 .5 Er 0 .5 Rh and GdRh. As apparent from FIG. 3, the attainable temperature can be lowered by setting the weight ratio of GdRh to 45-65%. FIG. 4 shows a change in generated refrigeration quantity with a temperature change, assuming isothermal change. A pressure range is from 20 bar at a high pressure to 6 bar at a low pressure. The generated refrigeration quantity is made dimensionless by an indicated refrigeration quantity. If the temperature is high, the helium gas 16 would be regarded as an ideal gas, and the generated refrigeration quantity made dimensionless would be substantially 1. However, as apparent from FIG. 4, the generated refrigeration quantity is suddenly lowered in the temperature region of 7K. or less. Such a point has not been clarified in the conventional multi-stage cold accumulation type refrigerator, causing a problem of heat generation due to sliding resistance from a large pressure of the third seal 7.
FIGS. 5A and 5B show a structure of the third seal 7a of a piston ring type. The piston ring 7a is radially outwardly pressed by the tension ring 28 to thereby tightly contact an outer circumferential surface of the piston ring 7a with an inner circumferential surface of the cylinder 10 and prevent pass of the helium gas 16. The larger the elastic force of the tension ring 28, the more tightly both the circumferential surfaces contact to more improve the sealability. However, as the pressure of the piston ring 7a becomes larger, the sliding resistance of the seal is increased to cause an increase in heat generation. Conventionally, since the generated refrigeration quantity has been considered to be equal to the indicated refrigeration quantity, the pressure of the tension ring 28 has been excessive. To the contrary, according to the present invention, the generated refrigeration quantity is calculated to select the elastic force of the tension ring 28 so as to reduce the leakage of the helium gas and generate refrigeration. For example, when the sliding resistance was set to be 4% of the indicated refrigeration quantity, an improved sealability was obtained. On the other hand, a quantity of leakage of the helium gas is dependent on a surface roughness of the inner circumferential surface of the cylinder 10. FIG. 6 shows a relationship between the surface roughness of the inner surface of the cylinder 10 and the attainable temperature of the third thermal stage 20. When the surface roughness of the inner surface of the cylinder 10 was set to 0.5 μm RMS, the attainable temperature was 3.68K.
FIG. 5C shows a preferred embodiment using the third seal 7b of a labyrinth type. A clearance between an outer circumferential surface of the labyrinth seal 7b and an inner circumferential surface of the cylinder 10 is made very small to thereby increase the resistance upon passing of the helium gas 16 therethrough and reduce the quantity of the helium gas 16 passing therethrough. Furthermore, as the sliding resistance of the labyrinth seal 7b is small, the heat generation can be reduced.
The internal uniform heating cold accumulating member 25 shown in FIG. 1 is formed of a rare earth substance such as ErRh and ErNi 2 having a large specific heat at very low temperatures, so as to increase a heat capacity of the cold generating section. As a result, a temperature change in a refrigeration cycle can be reduced, and the efficiency can be improved.
The external uniform heating cold accumulating member 26 can also exhibit the same effect as above. The external uniform heating cold accumulating member 26 may be formed from a helium tank instead of the rare earth substance as mentioned above.
FIG. 7 is a schematic illustration of an experimental system constructed for the purpose of providing the above-mentioned effect of the present invention. A low-temperature section of the refrigerator is accommodated in the vacuum tank 29 thermally insulated under vacuum. The radiation shield 37 serves to reduce heat penetration due to radiation to the low-temperature section. The helium gas in the helium cylinder 31 is reduced in pressure to about atmospheric pressure by the pressure reducing valve 32, and is introduced through the helium conduit 30 to the helium tank 26. The heater 34 serves to heat the third thermal stage 20, and the temperature sensor 36 serves to detect the temperature of the third thermal stage 20. As the result of the test carried out by using the above-mentioned experimental system, the inventors could liquefy the helium gas solely by the GM refrigerator for the first time in the world. FIG. 8 shows a refrigerating capacity of this refrigerator. As apparent from FIG. 8, the attainable temperature is 3.58K., which temperature is greatly lower than a currently recorded temperature 6.5K.
Generally, the rare earth substance is brittle, and when it is used for a long period of time, there is generated the fine powder 38 of the cold accumulating member as shown in FIG. 9, and the fine powder 38 is expelled into the third expansion chamber 17 to deposit onto the seal portion, causing an increase in leakage. The rare earth substance to be used for the cold accumulating member is almost made into a ferromagnetic material in a usable temperature region. According to the present invention, the trapping magnet 27 is provided to adsorb the fine powder 38 made ferromagnetic, so that the seal portion is not affected by the fine powder 38. The trapping magnet 39 is provided at the outlet of the third cold accumulator 1, so as to suppress the fine powder 38 from being expelled. Similarly, the trapping magnet 40 is provided at the center of the third cold accumulator 1, so as to suppress the fine powder 38 from being expelled.
FIG. 10 is a schematic illustration of a three-stage GM refrigerator utilizing the present invention, and FIG. 11 shows a refrigerating capacity of this refrigerator. As apparent from FIG. 11, it is possible to obtain temperatures less than 4.2K. which is a boiling point of helium. Referring to FIG. 10, reference numerals 50 and 51 denote the three-stage GM refrigerator and a compressor, respectively, and reference numerals 52, 53 and 54 denotes first, second and third heat stages, respectively.
Although the above-mentioned preferred embodiment is applied to a three-stage GM refrigerator, the present invention may be applied to two-stage or four or more-stage GM refrigerator which can exhibit a similar effect. Further, the present invention may be, of course, applied to any other refrigerators utilizing Solvay cycle, improved Solvay cycle, Vilmier cycle, Stirling cycle, etc.
In summary, the present invention can exhibit the following various effects.
(1) As the cold accumulating member of the cold accumulator is formed of a rare earth substance, a high efficiency of the refrigerator in a very low temperature region can be obtained.
(2) As the quantity of heat generation due to the sliding resistance of the seal is set to be smaller than the theoretical generated refrigeration quantity, a refrigerating capacity can be improved.
(3) As the thermal anchor is mounted on the outer surface of the seal sliding portion of the cylinder, and it is thermally connected to the high-temperature thermal stage, the heat generation due to the sliding resistance of the seal can be absorbed to thereby improve the refrigerating capacity.
(4) As the third thermal stage is mounted at the end of the displacer, and the uniform heating cold accumulating member is mounted at the end of the cylinder, temperature oscillation can be reduced, and the efficiency can be improved.
(5) AS the trapping magnet for adsorbing a fine powder of the cold accumulating member is mounted to the displacer, it is possible to suppress the fine powder from affecting the seal portion or the like, thereby improving the reliability for a long period of time.
Referring next to FIG. 12 which shows a preferred embodiment of a cryopump utilizing the multi-stage cold accumulation type refrigerator according to the present invention, reference 101 designates a three-stage GM refrigerator having a refrigerating capacity such that an attainable temperature is 4.2K. or less. A cold accumulating member of a third cold accumulator in this refrigerator is formed on GdRh and Gd 0 .5 Er0.5Rh. The refrigerator 101 includes a first heat stage 102, a second heat stage 103, a third heat stage 104, a first panel 105 mounted to the first heat stage 102, a second panel 106 mounted to the second heat stage 103, a third panel 107 mounted to the third heat stage 104, an active carbon 108 deposited on the third panel 107, and a vacuum container 109.
The first panel 105, the second panel 106 and the third panel 107 are refrigerated by the first heat stage 102, the second heat stage 103 and the third heat stage 104, respectively. The first heat stage 102 is operated at temperatures of about 50K. to refrigerate the first panel 105 functioning to shield radiation to the second panel 106. When steam strikes against the cryopump, it is frozen on the first panel 105. The second heat stage 103 is operated at temperatures of about 15K. to refrigerate the second panel 106 functioning to shield radiation to the third panel 107. On the second panel 106 are frozen nitrogen, oxygen and argon. The third heat stage 104 is operated at temperatures of about 4K. to refrigerate the third panel 107 on which Ne and H 2 are frozen. The active carbon 108 deposited on the inside surface of the third panel 107 serves to adsorb He which is not frozen at temperatures of about 4K.
FIG. 13 shows another preferred embodiment of the cryopump as mentioned above, wherein the same reference numerals as in FIG. 12 denote the same or corresponding parts. In this preferred embodiment, the active carbon 108 is deposited on both the second panel 106 and the third panel 107, so that an operation load of the active carbon 108 on the third panel 107 may be reduced.
As mentioned above, the cryopump according to the present invention employs a multi-stage cold accumulation type refrigerator having plural heat stages and capable of obtaining an attainable temperature of 4.2K. or less. Therefore, H 2 and Ne can be frozen even without the active carbon, and an adsorption quantity by the active carbon can be increased by lowing the temperature of the active carbon.
FIGS. 14 to 17 show some preferred embodiments of a superconducting magnet cooling device utilizing the refrigerator according to the present invention, wherein the same reference numerals throughout the drawings denote the same or corresponding parts.
Referring first to FIG. 14, the cooling device includes a vacuum tank 201 for a superconducting magnet 205, a first radiation heat shield 202, a second radiation heat shield 203, a helium tank 204 for accommodating the superconducting magnet 205, a liquid helium 206 for cooling the superconducting magnet 205, a vaporized gas 207 of the liquid helium 206, liquid drops 208 generated by re-cooling the vaporized gas 207, a supporting device 209 for supporting the helium tank 204 so as to be thermally insulated from the vacuum tank 201, a port 210 communicated with the helium tank 204, a vacuum section 215 for heat insulation, a multi-layer heat insulator 214 for heat insulation, a three-stage GM refrigerator 220, set screws 230 for connecting the first radiation heat shield 202 to a first heat stage of the three-stage GM refrigerator 220, set screws 231 for connecting the second radiation heat shield 203 to a second heat stage of the GM refrigerator 220, set screws 232 for connecting the helium tank 204 to a third heat stage of the GM refrigerator 220, bolts 229 for connecting the GM refrigerator 220 to the vacuum tank 201, a gasket 228 for vacuum sealing, a compressor 221 for compressing a helium gas, a high-pressure hose 222 for supplying the high-pressure compressed helium gas to the GM refrigerator 220, and a low-pressure hose 223 for returning the low-pressure helium gas expanded in the GM refrigerator 220 to the compressor 221.
The third heat stage of the three-stage GM refrigerator 220 is mounted to the helium tank 204 by the set screws 232 in such a manner as to make thermal resistance as small as possible. The cold generated by the third heat stage is transmitted through a partition wall of the helium tank 204 to the vaporized gas in the helium tank 204, so as to re-liquefy the vaporized gas.
The first heat stage and the second heat stage of the GM refrigerator 220 are mounted to the first radiation heat shield 202 and the second radiation heat shield 203, respectively, so as to coot the shields 202 and 203 to about 80K. and about 20K., respectively.
Although the cold generated by the third heat stage is transmitted through the partition wall of the helium tank 204 to the vaporized gas in the above preferred embodiment, the third heat stage may be exposed into the helium tank 204 as shown in FIG. 15. In this case, a gasket 236 for vacuum sealing is necessary.
FIG. 16 shows a modification of the above preferred embodiment, wherein a port 240 for inserting the GM refrigerator 220 is provided. The vaporized gas is reliquefied by the third heat stage, and the radiation heat shields are cooled by the first heat stage and the second heat stage through a partition wall of the port 240. Alternatively, as shown in FIG. 7, the port 240 may be formed into a multi-step structure, so as to enhance thermal contact between the heat stages and the radiation heat shields.
Although the above-mentioned preferred embodiments are applied to a superconducting magnet for MRI, the present invention may be applied to other superconducting magnets having a refrigerating load of several watts at 4.2K. such as a superconducting magnet for magnetic levitation and a superconducting magnet for accelerators.
In the conventional cooling device for a superconducting magnet (e.g. the cooling device for a superconducting magnet for MRI as shown in the 1st Cryogenic Engineering Summer Seminar Text (1988) p14 published by Cryogenic Engineering Association and the 34th Cryogenic Engineering Seminar Text (1985) p88 published by Cryogenic Engineering Association), a helium liquefier includes a heat exchanger and a Joule-Thomson valve. Therefore, such a cooling device is complex in structure and high in cost. Furthermore, the performance thereof is apt to be deteriorated, resulting in low reliability.
To the contrary, according to the present invention, the multi-stage cold accumulation type refrigerator capable of attaining temperatures of 4.2K. or less is combined with a superconducting magnet, so as to reliquefy the helium gas vaporized and simultaneously cool the radiation heat shields. Accordingly, the structure of the cooling device according to the present invention can be simplified at low costs, and the reliability can be improved.
FIGS. 18 to 20 show some preferred embodiments of a SQUID cooling device utilizing the refrigerator according to the present invention, wherein the same reference numerals throughout the drawings denote the same or corresponding parts.
Referring first to FIG. 18, the cooling device includes a refrigerator 301 capable of liquefying helium according to the present invention, a vacuum tank 302 formed of a non-magnetic material such as GFRP, a second thermal shield 306 mounted-to a second thermal stage 305, a third thermal stage 307, a helium condenser 308 thermally connected to the third thermal stage 207 for condensing helium 310, a heat pipe 309 for passing liquid and vapor of the helium 310, a SQUID 311 mounted at an end of the heat pipe 311, a thermal shield 312 formed of a non-magnetic material such as alumina so as to well transmit an external signal to the SQUID 311, a third cylinder 315, and a high-temperature superconductor 316 (e.g. yttrium compounds) coated on the outer surface of the cylinders 313, 314 and 315, the thermal stages 303, 305 and 07, and the thermal shields 304 and 306.
When the refrigerator 301 is operated, the first thermal stage 303 is cooled to about 40K., and the first thermal shield 304 is also cooled to about 40K. Further, the second thermal stage 305 is cooled to about 11K., and the second thermal shield 306 is also cooled to about 11K. When the third thermal stage 307 is cooled to a temperature capable of liquefying the helium 310, the helium 310 starts being liquefied in the helium condenser 308, and the helium 310 liquefied flows down in the non-magnetic heat pipe 309 by the gravity. Thus, the liquefied helium 310 is gathered at the end of the heat pipe 309 to cool the SQUID 311. Under the condition, the high-temperature superconductor 316 is made superconductive and completely diamagnetic to thereby completely shut off a magnetic noise generated in the refrigerator. Further, heat penetration due to radiation to the heat pipe 309 is reduced by the first thermal shield 304, the second thermal shield 306 and the non-magnetic thermal shield 312. Accordingly, the heat pipe 309 can be used for a considerably long period of time. As the vacuum tank 302 and the thermal shield 312 are formed of non-magnetic materials, a fine magnetic field can be measured by the SQUID 311.
Although the above preferred embodiment employs a single SQUID, the present invention may be applied to a system employing two or more SQUIDs. In the case of using a SQUID operable at high temperatures (e.g. 20K.), the helium 310 may be replaced by hydrogen or neon. Further, the high-temperature superconductor 316 may be replaced by the conventional superconductor.
FIG. 19 shows a modification of the above preferred embodiment, wherein the heat pipe 309 is not used but the SQUIDs 311 are directly mounted to the helium condenser 308 and the third thermal stage 307.
FIG. 20 shows a further modification of the above preferred embodiments, wherein the helium condenser 308 is connected through a pressure control pipe 323 to an external pressure controller 322, so as to control the pressure in the helium condenser 308, thereby further improving a temperature stability.
In the conventional cooling device for SQUID as shown in the 37th Cryogenic Engineering Seminar Text p165, for example, the SQUID is cooled-by the cold fed through a cooling pipe from the refrigerator, so as to avoid a magnetic noise to be generated from the refrigerator. However, such a system requires a compressor and a heat exchanger to cause a complex structure, and there is a possibility of the cooling pipe being choked or the like, causing a reduction in reliability. Additionally, a cooling temperature is affected by a stage temperature and a helium flow quantity to cause unstable operation of the SQUID.
To the contrary, the SQUID cooling devices shown in FIGS. 18 to 20 can completely shut off a magnetic noise generated from the refrigerator by means of the high-temperature superconductor. Further, in the case of using a heat pipe for cooling the SQUID, a degree of freedom of mounting of the SQUID can be made large, and a cooling temperature can be made stable.
FIGS. 21 to 25 show some preferred embodiment of a superconducting computer cooling device utilizing the refrigerator according to the present invention, wherein the same reference numerals throughout the drawings denote the same or corresponding parts.
Referring first to FIG. 21, the cooling device includes motor and valve 401 of the GM refrigerator, a first cylinder 402, a second cylinder 403, an interface 404 of the superconducting computer, a gate valve 405, an I/O cable 406, a logic and memory card 407 formed of a superconductor, a superconducting magnetic shield 408 for protecting the logic and memory card 407 from a magnetic field, a liquid helium bath 409 for containing a liquid helium for cooling the logic and memory card 407, which helium bath also serves as an outlet container for the I/O cable 406, a first thermal stage 410 of the GM refrigerator, a second thermal stage 411, a third thermal stage 412 for obtaining a temperature cable of liquefying the helium, a helium gas 416 to be supplied to the GM refrigerator, a return gas 417 to be output from the GM refrigerator, a third cylinder 418 of the GM refrigerator which cylinder includes a cold accumulating member formed of GdRh and Gd 0 .5 Er 0 .5 Rh, a vacuum tank 423, and a radiation shield tank 425 disposed in the vacuum tank 423.
The liquid helium bath 409 is thermally connected to the first thermal stage 410 and the second thermal stage 411 of the GM refrigerator. The first thermal stage 410 is cooled-to about 50K., and the second thermal stage 411 is then cooled to 10-15K. Further, the third thermal stage 412 is cooled to about 4.2K. capable of condensing the helium gas. The liquid helium in the helium bath 409 is partially vaporized by heat generation from the logic and memory card 407 of the superconducting computer or heat penetration into the helium bath 409. Then, the helium gas vaporized is cooled and condensed by the third thermal stage 412 to drop into the helium bath 409.
In the conventional cooling device for superconducting computers as mentioned in NBS SPECIAL PUBLICATION 607 p93-102, for example, a JT loop is used. To the contrary, the cooling device of the above preferred embodiment does not require such a JT loop to thereby make the structure sample and compact. Further, it is easy to handle, and it is improved in reliability and service life.
FIG. 22 shows a modification of the above preferred embodiment, wherein a helium reservoir 419 enclosing helium is mounted on the third thermal stage 412. Since a specific heat of helium at temperatures near the liquefying temperature of the helium becomes large, the helium reservoir 419 serves to stabilize the temperature of the third thermal stage 412.
FIG. 23 shows a further modification of the above preferred embodiment, wherein portions of the liquid helium bath 409 between the first and second thermal stages and between the second and third thermal stages are connected together through heat insulators 421 such as GFRP, so as to prevent heat penetration due to conduction from the outside at an ordinary temperature.
FIG. 24 shows a further modification of the above preferred embodiment, wherein a radiation shield plate 424 formed of copper, for example, is mounted on the liquid helium bath 409, so as to prevent radiation heat.
FIG. 25 shows a further modification of the above preferred embodiment, wherein a helium reservoir 419 enclosing helium is mounted to the third thermal stage 412, and a substrate 420 for mounting the logic and memory card 407 is mounted to the helium reservoir 419. An I/O cable outlet container 426 is provided to lead out the I/O cable 406 connected to the logic and memory card 407. The substrate 420 is cooled to a helium liquefying temperature by conduction of the cold from the helium reservoir 419. As a result, the logic and memory card 407 is made operable. Thus, the preferred embodiment does not require the liquid helium bath as shown in FIGS. 21 to 24, thereby reducing the cost and making the structure compact.
Although the above-mentioned preferred embodiments use a three-stage GM refrigerator, the present invention may be applied to any other cold accumulation type refrigerators capable of liquefying helium.
FIGS. 26 to 28 show some preferred embodiments of an infrared telescope cooling device utilizing the refrigerator according to the present invention, wherein the same reference numerals throughout the drawings denote the same or corresponding parts.
Referring first to FIG. 26, the cooling device includes a case 502, a first reflecting mirror 503 disposed in the case 502 for first reflecting infrared radiation 501 entering the case 502 from the outside, a second reflecting mirror 504 for further reflecting the infrared radiation 501 reflected on the first reflecting mirror 503, an infrared device 505 for receiving the infrared radiation 501 reflecting on the second reflecting mirror 504, a three-stage GM refrigerator 508 capable of attaining temperatures of 2K. to 4.2K. and including a cold accumulating member of a third cold accumulator formed of GdRh and Gd 0 .5 Er 0 .5 Rh, for example, a helium reservoir 509 thermally contacting the infrared device 505 and enclosing helium, a helium gas 510 to be supplied to the three-stage GM refrigerator 508, a return gas 511 to be returned from the refrigerator 508, a first thermal stage 515, a second thermal stage 516 and a third thermal stage 517 of the three-stage GM refrigerator 508.
The infrared radiation 501 entering the case 502 from the outside is first reflected on the first reflecting mirror 503, and is then collected to the second reflecting mirror 504. The infrared radiation 501 collected is further reflected on the second reflecting mirror 504, and is then collected to the infrared device 505. On the other hand, the third thermal stage 508 of the three-stage GM refrigerator 508 is cooled to 2K. to 4.2K., and the helium reservoir 509 thermally contacting the third thermal stage 508 is accordingly cooled to 2K. to 4.2K. As the specific heat of the helium enclosed in the helium reservoir 509 at this temperature region is large, there is hardly generated temperature oscillation in the helium reservoir 509 even when temperature oscillation is generated in the third thermal stage 517. Therefore, there is hardly generated temperature oscillation in the infrared device 505 thermally contacting the helium reservoir 509, and the infrared device 505 is cooled to 2K. to 4.2K. Thus, the infrared device 505 is made operable at the temperatures of 2K to 4.2K. to receive the infrared radiation reflected on the second reflecting mirror 504 and collected to the infrared device 505.
FIG. 27 shows a modification of the above preferred embodiment, wherein a first shield plate 513, a second shield plate 512 and a third shield plate 514 are mounted to the first thermal stage 515, the second thermal stage 516 and the third thermal stage 517, respectively. The first shield plate 513 is cooled to about 50 K. by the first thermal stage 515 to function to shield radiation against the second shield plate 512. The second shield plate 512 is cooled to about 15K. by the second thermal stage 516 to function to shield radiation against the third shield plate 514. The third shield plate 514 is cooled to 2-4.2K. by the third thermal stage 517 to function to shield radiation against the infrared device 505. Thus, the radiation heat to the infrared device 505 and the first and second reflecting mirrors 503 and 504 can be reduced.
Referring to FIG. 28 which shows a further modification of the above preferred embodiment, a pressure control system for controlling the pressure in the helium reservoir 509 is connected to the cooling device. The pressure control system includes an input port 518 for inputting a signal for controlling the pressure, a signal line 519 connected to the input port 518, a digital input circuit 520 for receiving the digital signal input from the input port 518 through the signal line 519, a CPU 521 for receiving an input signal from the digital input circuit 520, an output control circuit 522 for receiving an output signal from the CPU 521, an actuator 523 for receiving an output signal from the output control circuit 522, a pressure conduit 524 connected to the helium reservoir 509, a pair of valves 525A and 525B connected to the pressure conduit 524, a high-pressure tank 526 connected to the valve 525A, and a vacuum tank 527 connected to the valve 525B.
In changing a temperature of the infrared device 505, an input value is input to the input port 518, and it is transmitted through the digital input circuit 520 to the CPU 521. Then, an output signal as a function of temperature is output from the CPU 521. The output control circuit 522 adjusts a magnitude of the output signal from the CPU 521 and outputs an adjusted signal to the actuator 523. Then, the actuator 523 opens and closes the valves 525A and 525B according to a magnitude of the signal from the output control circuit 522.
In the temperature region of 2K. to 4.2K., the helium in the helium reservoir 509 As in the boiling condition. The lower the pressure of the helium, the lower the boiling point thereof. Therefore, the temperature of the infrared device can be reduced by reducing the pressure of the helium in the helium reservoir 509. That is, the valve 525B connected to the vacuum tank 527 is opened to reduce the pressure of the helium in the helium reservoir 509. The pressure in the helium reservoir 509 is detected by a pressure sensor 528, and an output signal from the pressure sensor 528 is converted to a digital signal by an A/D converter 529. Then, the digital signal is output to the CPU 521. When the pressure becomes a desired pressure, a signal for closing the valve 525B is output from the CPU 521.
In contrast, when the temperature of the infrared device 505 is intended to be increased, the pressure of the helium in the helium reservoir 509 may be increased by opening the valve 525A connected to the high-pressure tank 526.
Thus, the temperature of the infrared device 505 can be desirably controlled in the temperature range of 2K. to 4.2K.
In the conventional infrared telescope as shown in NEWTON COLLECTION ASTRONOMICAL OBSERVATION (Kyoikusha), a liquid helium tank is required. To the contrary, the infrared telescope according to the present invention does not require such a liquid helium tank, and it is not required to occasionally supply a liquid helium.
While the invention has been described with reference to specific embodiment, the description is illustrative and is not to be construed as limiting the scope of the invention. Various modifications and changes may occur to those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
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In a multi-stage cold accumulation type refrigerator including a compressor disposed at an ordinary temperature, a helium gas as a common operating fluid to be compressed by the compressor, and one or more expansion chambers and cold accumulators of different temperature levels; a cold accumulating member of the cold accumulators is formed of an alloy or compound containing a rare earth metal, so that the efficiency of the refrigerator can be improved. Further, a heat generation quantity due to sliding resistance of a seal is set to be smaller than a theoretical generated refrigeration quantity to be obtained on the assumption of isothermal expansion in the expansion chambers, so that the refrigerating capacity can be improved. The refrigerator is applied to a cooling device for cooling a superconducting magnet, SQUID, superconducting computer, infrared telescope, etc.
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BACKGROUND OF THE INVENTION
This invention relates generally to a tester for testing the condition of an ignition system of a combustion engine and more particularly it relates to a tester of the type which reduces the electrical energy stored in the primary winding of an ignition coil until an ignition slip or miss occurs.
A tester of this type is known from prior art in which an electrical load is connected in the primary circuit of the ignition coil. Power loss of this load is increased so long until the first ignition slip caused by the lack of energy takes place during the igniting process of the gas air mixture in the combustion spaces of the engine. At the moment of occurrence of this ignition slip the available ignition energy is ascertained and compared with a reference value which is characteristic for the normal operation of a tested ignition system whereby the difference between the two values indicates a measure for the reserve of the ignition energy and thus the condition of the whole ignition system. The disadvantage of this known testing device is the limitation that only the ignition system as a whole can be tested or in other words that it can be ascertained only whether the ignition system is in good working order or not. Accordingly this known device enables only a coarse estimate of the condition of the igniting system and in the case of a deviation from a nominal value the component parts of the system have to be individually tested.
SUMMARY OF THE INVENTION
It is therefore a general object of the present invention to overcome the aforementioned disadvantage.
More particularly, it is an object of the present invention to provide an improved ignition tester of the above-described type in which the parts of the ignition system assigned to respective cylinders of the combustion engine can be selectively checked in order to determine in which individual circuit of the ignition system the trouble takes place, for example, before or after the distributor, and in the case when the fault is after the distributor in which branch of the distributing circuit.
In keeping with these objects and others which will become apparent hereafter, one feature of the invention resides, in a tester of an ignition system having a power source, an ignition coil, a plurality of sparking plugs and a distributor for successively connecting respective plugs to the coil, in a combination which comprises means for adjustably reducing electrical energy normally stored in the coil, and selective switching means controlled by successively activated parts, for connecting the energy reducing means to the coil circuit when a sparking action in the plug under test is initiated.
In the preferred embodiment of this invention, the selective switch includes a scaler or counter which produces an output pulse for a predetermined number of input pulses derived from the actuation of respective sparking plugs and this output pulse switches the energy reducing means to the primary circuit of the ignition coil.
It is also of particular advantage when instead of an electrically passive load which is adjustable for reducing electrical energy stored in the primary circuit of the ignition coil, an adjustable power source is employed so that the energy supply for the ignition system can be adjusted for ready use to such an extent until first ignition slip in a preselected cylinder of the combustion engine takes place.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic circuit diagram of an ignition system of a four cylinder combustion engine including the testing device of the invention;
FIG. 2 is a plot diagram of the primary current of the ignition coil versus time in the circuit of FIG. 1;
FIG. 3 is another embodiment of the testing device of this invention;
FIG. 4 is a plot diagram of primary current versus time in the modification of FIG. 3; and
FIG. 5 shows an adjustable power source for controlling the stored energy in the primary circuit of the ignition coil.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring firstly to FIG. 1, the ignition system of a combustion engine includes a power source 10 of an operative voltage which is connected at one pole thereof to the ground conductor and at the other pole to a contact 30 of power switch 11. The other contact 15 of switch 11 is connected via an adjustable resistor 12 to a terminal 15a of the primary winding 13 of ignition coil 14. The other terminal 1 of the primary winding 13 is connected via contact breaker 17 to the ground conductor, the contact breaker 17 being bridged by ignition capacitor 16. Terminal 1 is also connected to the secondary winding 18 of coil 14 whereby the otherterminal 4 of the secondary winding 18 is connected to the rotary finger 19of distributor 20. The distributor 20 distributes the energy stored in ignition coil 14 between sparking plugs 21 through 24 of the engine. A non-illustrated crank shaft of the engine drives the rotary finger 19 of the distributor and a cam 26 which controls the make-and-brake contact 17.The terminal 1 is further connected to the input of a switching multistage counter or scaler 33 which acts as a selective switch in such a manner that it delivers an output impulse from a preselected stage when a predetermined number of input pulses corresponding to each actuation of contact breaker 17 is completed. Scaler 33 is also controlled by means of a synchronizing pulse generated in a pick-up 34 which is coupled to a branch conduit of distributor 20 corresponding to a preselected sparking plug. The sparking plug 21 is assigned for example to the first cylinder of the combustion engine. By means of the synchronization pulse from pick-up 34 the scaler 33 is synchronized with the cycles of rotary arm 19 of distributor 20. The output pulse from scaler 33 opens a switch 35 whichis connected between contacts 15 and 15a parallel to the adjustable resistor 12 and thus reduces the normal current through the primary winding 13 of coil 14.
The principle of operation of the ignition system as illustrated in FIG. 1 is as follows: At closed contact breaker 17, the primary winding 13 of coil 14 is connected via closed switches 35 and 11 to the power source or battery 10 and a current I p flows through the primary winding. This current does not increase suddenly in response to the closing of contact breaker 17 but with a time delay relative to the application of the battery voltage and gradually raise to a certain end value, the so-called rest current value determined by the ohmic resistance of the primary winding 13. During the increased flow of the current a magnetic field builds up in the primary winding and an electric energy is stored in the latter. Upon completion of the storing process contact breaker 17 opens and interrupts the primary rest current. At the same instant the magnetic field breaks down and by induction generates both in the primary winding and in the secondary winding 18 a voltage which is the higher the faster the magnetic field breaks down. The speed of the collapse of the magnetic field is assisted by condensor 16 which is connected parallel to the contact breaker 17. The high voltage induced in the secondary winding 18 is applied via the distributing finer 19 of the distributor 20 to individual sparking plugs 21 through 24 whereby the resulting ignition spark successively ignites the fuel-air-mixture in combustion spaces of the engine.
In FIG. 2 there is plotted a diagram of the primary current I p againsttime T. When the ignition system is in a good working order, the rise of the primary current corresponds to the curve 27 whereby the ignition energy W Z stored in the coil 14 at a time point t is
W.sub.Z =1/2L.sub.s I.sup.2.sub.t
which in a workable ignition system is fully available. L indicates the inductivity of the primary winding 13 of coil 14.
If in the circuit of FIG. 1 the adjustable resistance 12 is increased from zero, then a voltage drop takes place on the resistor 12 which during a time interval t of the current flow represents a power loss. Experiments have shown that by increasing this series resistance the performance of the engine remains initially constant and that only at a certain minimum current I p will the performance abruptly drop. Consequently if the primary current I p flowing through the primary winding 13 of coil 14 is continuously reduced so the available ignition energy stored in the coil is also reduced and when the first ignition slip caused by the lack of available energy occurs that means when the performance of the engine starts to slip so this available ignition energy is ascertained and compared with a nominal value of the ingition energy, namely with a storedenergy value at which the ignition system operates reliably. From the difference between the two energy values there results so-called reserve of the ignition energy which is a measure for the condition of the whole ignition system.
Curve 28 in FIG. 28 illustrated the time plot of the current through the primary winding 13 of coil 14 at a time point when the first ignition sliptakes place. This characteristic curve of the primary current indicates according to the equation W Z =1/2L s I 2 t the minimum applicable ignition energy for the particular ignition system. The difference between this minimum energy and the normal energy is the aforementioned ignition energy reserve which gives an information about the condition of the system. If this difference is large or if it exceeds a predetermined value, so the ignition system is in a good working order. If the ignition energy reserve is too small and if it is below the predetermined nominal value then the condition of the ignition system is not in order.
By means of scaler 33 and by switch 35 controlled by the scaler, the ignition energy in coil 14 can be reduced only then when fuel-air mixture in a preselected cylinder of the engine is about to ignite. For this purpose scaler 33 is synchronized with the actuation order of individual cylinders of the combustion engine by means of a probe or pick-up 34 coupled for example to a lead-in wire for a plug pertaining to the first cylinder of the engine. The pick-up 34 generates a synchronization pulse which is applied to the scaler 33 and sets the same to zero or to 1 when the sparking of the plug pertaining to the first cylinder takes place. With each actuation of contact breaker 17, a pulse is delivered to the counting input of scaler 33 and is transferred therein about a counting place whereby upon reaching a predetermined number of the input pulses thescaler produces an output pulse which opens the normally closed switch 35. In doing so, the hitherto short-circuited adjustable resistor 12 becomes effective and the stored ignition energy is reduced according to the setting of the tapping arm of the resistor 12. In this manner it is possible selectively to find out the ignition energy reserve for the part of the ignition system pertaining to the selected cylinder of the combustion engine. In addition, apart from the exact pinpointing of the trouble in the ignition system itself, it is also possible to determine whether the failure is before the distributor 20 or behind the latter.
FIG. 3 shows a similar ignition system as FIG. 1 and therefore the description of operation of its individual components parts is omitted forthe sake of simplicity. Instead of resistor 12 which in the preceding example of FIG. 1 has been connected in series with the primary winding ofignition coil 14, in the embodiment according to FIG. 3 there is provided an adjustable resistor 29 which is connected parallel to the contact breaker 17. The resistor 29 reduces the ignition energy delivered to sparking plugs 21 through 24 in such a manner that by reducing the value of the resistor 29 the rest current flowing through the primary winding 13of coil 14 becomes larger.
The operation of this embodiment is explained with reference to FIG. 4 where curve 30 indicates the plotting of the primary current I t versus time when an infinitely large resistor 29 is adjusted. If the resistor 29 is reduced then a rest current I O flows through the primary winding as indicated by broken line 31. As a consequence the primary current does not start raising to its maximum value from a normally negligible rest current but starts from the value I O and itstime development is indicated by the characteristic curve 32. The values readable from the curves 30 or 32 represent the available ignition energy.If the adjustable resistor 29 and thus the available ignition energy is setto such a value at which the first ignition slip occurs, then this value corresponds to the minimum energy which is necessary for functioning of the ignition system. The ignition energy reserve can be again ascertained from the difference between the minimum ignition energy and an energy value which is prescribed for optimum operation of a given ignition system, that is a maximum ignition energy, the ignition energy reserve cannot be determined. Also in this modification a simple good-bad indication of the condition of the ignition system of the engine is possible. Similarly as in the embodiment of FIG. 1, also in this example the scaler 33 is synchronizable by a trigger pulse pick-up or generator 34and the scaler actuates switch 36 which in this embodiment is in series with the adjustable resistor 29. Normally the switch 36 is open so that the adjustable resistor 29 has no effect on the operation of the ignition system. The cylinders of the combustion engine are assigned to respective counting places or stages of scaler 33 and by initiating the firing of a selected cylinder the switch 36 is closed and as a result the energy available from the primary winding of the coil is diminished. By virtue ofthe reduction of the ignition energy at a time point at which fuel-air mixture in a predetermined cylinder of the engine is about to be ignited it can be ascertained whether the part of the ignition system assigned to this particular cylinder is in order or whether a trouble before or after distributor 20 takes place. By switching the stages of scaler 33 that means by actuating the switch 36 by a different output pulse of the scaler33 it is possible to test the remaining cylinders of the engine or the branches of the ignition circuit pertaining to these respective cylinders.
FIG. 5 illustrates the same ignition system as in FIG. 1. Instead of an adjustable resistor in the primary winding, however, there is employed an adjustable power source, that is an adjustable source of voltage 37 or as indicated by broken lines, an adjustable current source 38 by means of which the energy in the coil 14 is reduced. In this embodiment instead of changing the adjustable resistor 12 or 29 the energy supply is reduced by reducing the voltage of voltage source 37 or supply current from current source 38 to a point at which the first ignition slips occur. By means of such an adjustable power source 37 or 38 it is possible to ascertain not only the ignition energy reserve of the whole ignition system but also to find out selectively the condition of individual parts of the circuit provided of course that the system is provided with the scaling and switching devices 33 and 35 as illustrated in FIGS. 1 and 3 for reducing the ignition energy only at preselected cylinders of the engine.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied in specific examples of ignition testing devices, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
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The device for testing an ignition system of a combustion engine comprises an adjustable load connected in the primary winding of the ignition coil by means of which the stored energy is so long reduced until due to the deficient energy the first ignition slip of the fuel-air-mixture occurs. This reduced energy is compared with the nominal or normal energy required for proper operation of the ignition system and the difference between the two values determines a measure for ignition energy reserve and consequently a measure for the condition of the whole ignition system. The energy reserve is measured selectively always for a part of the ignition system, that means for a cylinder of the engine. For this purpose a selective switch is employed using a scaler fed by pulses derived from the contact breaker and synchronized by a pulse from the part of the cylinder under test produce an output pulse which connects the loading member to the primary winding of the ignition coil.
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TECHNICAL FIELD
[0001] The invention relates to a method for integration of a large-caliber gun on a ship, as claimed in the features of the precharacterizing clauses of claims 1 and 2 , and to a ship gun as claimed in the features of the precharacterizing clause of claim 6 .
PRIOR ART
[0002] According to the prior art, it is known for ships currently to fire up to ranges of 15 to 18 km with munition calibers of 57, 76, 100 up to a maximum of 127 mm. A number of nations have started to develop guided missiles with the capability to attack land targets. The effectiveness of the guns used is considered to differ depending on the caliber, the rate of fire and the type of ammunition used. However, in general it can be stated that the effect on the target increases with the caliber. Large-caliber guns of the types used by Army artillery are currently not used for this purpose because the ship structure will not withstand the recoil forces of large-caliber ammunition in the long term. Of the guns which are used on land, it is known that large-caliber ammunition can be fired accurately at targets at ranges up to 40 km. The recoil effects that occur in this case are minimized by appropriate technical solutions, such as recoil dampers.
[0003] The ship ammunition that is used at the moment is specially manufactured and is not compatible with land ammunition. Other ammunition, for example armor-piercing ammunition etc, cannot be used. In some circumstances, there are resupply difficulties during operations abroad. A further disadvantage of the currently used ship ammunition is the short range, as a result of which land targets cannot be attacked without considerable risk to the ship. A further disadvantage of the comparatively small caliber of ship guns is that the guns are susceptible to weather influences, for example wind, so that small ammunition is subject to comparatively wide scatter.
[0004] A further disadvantage of the known ship projectiles mentioned above is that they cannot carry intelligent submunitions, for example cluster munitions or smoke. In order to be effective, a high hit accuracy is required, that is to say a greater number of shots will be necessary in some circumstances.
[0005] The gun turrets that are currently fitted to ships are not gas-tight. Furthermore, they are hard-mounted on the ship, that is to say they are rigidly connected to the ship, which means that the recoil forces resulting from possible use of large-caliber ammunition would be introduced directly into the ship structure and would lead to its destruction. Reinforcement of the steel in the ship structure would lead to a heavy weight and the obvious disadvantages associated with this, as well as leading to considerable additional costs.
[0006] A gun such as this is known from EP 0 051 119 A1. An automatic loading system for large-caliber ammunition is described. In this case, a Howitzer (155 mm) is mounted on a carriage. The carriage is in turn firmly installed on a ship deck. This results in the problem that the recoil forces from the gun/carriage are introduced directly into the ship structure.
[0007] When conventional ship guns are used, the rolling of the ship about its longitudinal axis leads to considerable problems in the determination of the coordinates, so that the aiming accuracy also suffers, with undesirable scatter occurring.
DESCRIPTION OF THE INVENTION
[0008] The object of the invention is to satisfy the existing military requirements for provision of the capability for naval fire support (NFS) for the use of military ships in the coastal area, with fire support for amphibious operations being of particular importance in this context, for which purpose the projectile range should be considerably increased so that it is also possible to attack inland targets with a high hit accuracy. The aim is to achieve this object for newly built ships and during ship conversions without any major modifications to the steel structure and with as little financial cost and time penalty as possible.
[0009] This object is achieved by the features specified in patent claims 1 and 5 .
[0010] The invention is based on the knowledge that the use of land guns on ships, which has not been possible until now, satisfies the new naval requirement by the use of existing technology, which even exceeds expectations, rather than by expensive new development. The use of the land guns with a caliber of >127 mm on a ship advantageously makes it possible to use the proven technology of large-caliber land guns for newly built ships. In a further advantageous manner, the turret of a land gun can be connected to an adaptor plate and a shock-absorbing mounting and can be installed on the ship in such a way that the existing steel structure of the ship withstands the increased recoil forces. It is particularly simple for this installation to be in a modular form, so that no significant modifications need be made to the ship, and the installation can be carried out in a short time. Land guns with a caliber of >127 mm can be used without modification, with the recoil forces to be transmitted to the gun deck being absorbed in a particularly advantageous manner by a shock-absorbing mounting so that the advantageous adaptation (which can be produced in a technologically simple manner) and refinement of the adaptor plate and additional shock damping for the gun deck allows the ship technology standard to be linked to the land technology standard, with this new naval requirement being covered by existing land guns, preferably from the armored 155 mm howitzer, rather than by expensive new development.
[0011] The modular (for example) use of the turret and of the weapon system from the armored 155 mm howitzer as a ship gun makes it possible in a particularly advantageous manner to achieve a long range and high effectiveness on the target with little scatter. The gun according to the invention can also advantageously carry intelligent submunitions, for example cluster munitions or smoke munitions. In the coastal area, the use of a turret with a weapon system from the armored 155 mm howitzer as a ship gun allows fire support for land operations from a safe position with an advantageous range of >40 km. In a further advantageous manner, the modular installation of the armored howitzer on the ship can be sealed such that it is NBC-proof by the use of a radial damper, thus preventing any danger to the operator.
[0012] When the armored 155 mm howitzer is used as a ship gun, the recoil forces must be reduced. A shock-absorbing, elastic mounting results in the introduction of the force being extended over time, thus resulting in technically acceptable residual accelerations for the ship deck. Despite the use of this elastic mounting, an attitude reference arranged above the elastic mounting on the gun guarantees correct target aiming. This attitude alignment is made possible by arranging an inertial platform with GPS and satellite navigation on the turret, which is used to determine the three-dimensional position of the weapon barrel and the geographical position on the earth, thus avoiding the disadvantages of the ship-related influences on previous ship guns. For the reason mentioned above, the invention now allows shots to be fired from a moving ship at a moving target.
[0013] The long range allows the ship to be further away from the land, thus making it considerably more difficult to find the position of the ship. In contrast, land targets can easily be located from the ship by means of helicopters and drones. The invention also advantageously allows the use of projectiles with submunitions, as a result of which, when bomblets are used, it is in any case possible to attack targets without requiring 100% exact target coordinates, which represents a particular advantage for attacks from ships at sea. In a further advantageous manner, the invention allows the combat range for seaborne targets at sea to be doubled. The proven, intelligent sensor system of the armored howitzer allows the turret to always be newly aimed even though the ship is continuing to move. The high aiming accuracy results in a considerable reduction in the number of shots to be fired. The use of the turret and the weapon system from the armored 155 mm howitzer results in ammunition compatibility between the various land and seaborne armed forces units. In future, the invention will also allow naval ships to attack targets well in land, with the use of intelligent (sub-) munitions also being possible.
BRIEF DESCRIPTION OF THE DRAWING
[0014] The invention will be described in detail with reference to one exemplary embodiment, in the following figures.
[0015] FIG. 1 shows a side view of the modular installation of a turret with a weapon system from an armored howitzer on a ship.
[0016] FIG. 2 shows the modular configuration of the turret of the armored howitzer, illustrated enlarged.
[0017] FIG. 3 shows a plan view of a previous ship gun with the mounting device on the deck, which is also used for mounting the turret of the armored 155 mm howitzer.
APPROACHES TO IMPLEMENTATION OF THE INVENTION
[0018] FIG. 1 shows the configuration of a land gun 1 on the upper deck 7 of a naval forces ship 2 . The illustrated example shows a turret 3 , which can rotate, with armament 15 (which can be elevated) from a land gun, based on the example of the armored 155 mm howitzer that is successfully used by the land-based armed forces.
[0019] The turret 3 is equipped with an inertial platform (which cannot be seen) with GPS satellite navigation on the turret 3 . This measures the attitude of the barrel 3 in three dimensions, and the geographical position on the earth. The accurate position of the gun turret 3 is determined by satellite navigation, in consequence allowing the necessary aiming of the barrel 15 to be calculated. A fire control computer (which is not illustrated) receives the desired target coordinates and determines the necessary ballistic curve independently of ship-dependent influences. In order to fire a shot, the turret 3 is rotated about its axis in accordance with the target calculation, and the barrel 3 is elevated about the trunnion axis 16 .
[0020] The recoil forces from the weapon barrel 15 occur only after the shot has been fired. The aiming required for the next shot must be calculated again. On the ship, it is necessary to prevent the recoil forces from causing damage to the ship structure. This is advantageously achieved by means of an adaptor 4 (as illustrated in FIG. 2 ) and an adaptor plate with a shock-absorbing mounting 5 , which are connected to one another and are installed on the ship in such a way that the existing steel structure of the ship 2 will withstand the increased recoil forces.
[0021] The shock-absorbing mounting 5 is supported by a mounting frame 6 . The mounting frame 6 can be mounted together with the adaptor plate in the turret in a modular form, as a unit. In this case, the mounting frame 6 is designed such that it equalizes out the space of a hole which is provided on the free deck 7 of the ship, and can be mounted on the existing hole rim area 9 of the deck 7 .
[0022] This is achieved by means of a multiple screw attachment 19 , of appropriate size, in the rim area 9 as the connection to the ship structure, which can be connected directly to the upper deck without any intermediate foundation (for example encapsulation compound).
[0023] The lower half of the turret ring mount 12 is connected to an intermediate frame 4 , 13 and/or to the adaptor 4 or the adaptor plate, or is inserted in it, with the intermediate frame 13 being connected to the shock-absorbing mounting 5 . The adaptor plate 4 and the intermediate frame 13 are shaped appropriately (in a manner which is not illustrated) and can be scaled appropriately for the respective distance between bulkheads, with integrated reinforcing structures for static and dynamic introduction of the forces resulting from the weight of the gun into the structure of the ship on which it is mounted.
[0024] The shock-absorbing mounting elements 5 comprise energy-absorbing damper and shock elements and, with a damping movement of approximately 150 mm, reduce the forces to be transmitted to the deck to an acceptable level. The shock-absorbing mounting 5 comprises mounting elements 5 ′ which are arranged like segments on the circumference. The mounting elements 5 ′ are connected to the intermediate frame 4 , 13 in such a way that they absorb compressive and tensile forces depending on the firing direction and elevation angle, and are accordingly compressed or extended elastically in order to absorb shock. The mounting elements 5 ′ can be loaded and are elastically deformable on a number of axes corresponding to the firing direction, and are composed, for example, of a rubber mixture, a steel spring or some other suitable elastically deformable spring or damping element.
[0025] The mounting frame 6 is designed in such a way that it is fitted as a unit on the deck, and can be firmly connected, in a modular form to the shock-absorbing mounting 5 and the turret 3 . The mounting frame 6 also allows installation in a different sequence. For example, the frame 6 can also be mounted on the deck first, with the remaining parts subsequently being inserted into the mounting frame.
[0026] A radial damper 14 , which is preferably in the form of a hollow rubber flexible tube, is arranged between the intermediate frame 13 and the mounting frame 6 , for air-tight NBC sealing.
[0027] On the free deck, a sealing skirt 10 protects the mounting elements 5 and, to some extent, the mounting frame 6 against waves of water. The module 18 of the armored howitzer can be connected to the ship in a shock-proof manner in various ways, which are not illustrated.
[0028] A deformable seal between the lower face and the upper deck ensure gas-tightness as well as grounding/electrical bonding. The installation of the armored howitzer on a naval forces ship also leads to the following advantageous improvements:
the ammunition supply can be fully automated; STEALTH technology is used for the turret; horizontal feeding is possible; the turret can advantageously be connected to the compressed-air system in the ship, so that there is no need for a separate compressor for an automatic loader; the use of active barrel coolant; the use of an extended recoil device in order to simplify the damping elements; link between the fire control and the operational system on the ship, and transfer of target data from ship-protected fire control devices.
LIST OF REFERENCE SYMBOLS
[0000]
1 Gun
2 Ship
3 Turret
4 Adaptor plate
5 Shock-absorbing mounting
5 ′ Damping element/mounting element
6 Mounting frame
7 Deck
8 Hole
9 Rim area
10 Sealing skirt
11 Turret basket area
12 Turret ring mount
13 Intermediate frame
14 Radial damper
15 Armament/weapon system/barrel
16 Trunnion axis
17 Ring mount part
18 Module
19 Multiple screw attachment
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A method for integrating a large-calibre gun on a ship, including connecting a turret having an armament of a lad gun with a calibre >127 mm in a modular configuration to an adaptor plate and a shock-absorbing mounting, and installing the turret on the ship so that an existing steel structure of the ship withstands increased recoil forces from the armament.
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BACKGROUND OF THE INVENTION
This invention relates to a pneumatic shuttle picking mechanism and in particular, to a pneumatic picking mechanism in which a piston is moved in a cylinder by pressurized fluid and a rod attached to the piston drives a weaving shuttle.
In mechanisms of this type, the flow of the pressurized fluid from a reservoir to the cylinder is controlled by a main valve having a valve seat, a valve member and a valve guide in which the valve member is slidably mounted. An auxiliary valve actuates the main valve by establishing a pressure differential between the front and rear sides of the valve member.
Such a pneumatic shuttle picking mechanism is disclosed in U.S. Pat. No. 2,677,933. In the mechanism of the '933 Patent, the reservoir annularly surrounds the cylinder, and the valve seat is formed by the open end of the cylinder into which the forward cylindrical end of the valve member can be pushed to close the main valve. The pressure prevailing in the cylinder, and the operating pressure prevailing in the reservoir surrounding the cylinder affects the front face of the valve member. The rear face of the valve member can be subjected to high pressure by way of the auxiliary valve, which causes closure of the main valve, or to atmospheric pressure, which causes opening of the main valve.
With the main valve open, the pressurized gas in the reservoir flows into the cylinder and moves the piston which drives the shuttle by way of the piston rod. With the main valve closed, there exists a connection from the cylinder cavity to the outside through a passage in the main valve. Gas present in the cylinder cavity can thus escape as the piston is urged into its starting position by the arriving shuttle. In this way, the pneumatic picking mechanism acts also to decelerating the shuttle.
In the mechanism of the '933 patent it is a disadvantage that a relatively large part of the energy accumulated in the reservoir by the pressurized gas is required for opening the main valve. It is a further disadvantage that the piston is returned to its starting position exclusively by the kinetic energy of the arriving shuttle. No means are provided to return the piston, and with it the shuttle, to its starting position, if the piston does not reach this position solely by the kinetic energy of the shuttle.
U.S. Pat. No. 3,698,444 describes a pneumatic picking mechanism in which the piston of the mechanism drives the picking arm by way of a crank mechanism. In this case, pressurized fluid is supplied from a reservoir to a cylinder under the control of a magnetically actuated main valve. The '444 mechanism, however, requires a significant investment in mechanical components owing to the crank mechanism.
U.S. Pat. No. 4,082,118 describes a further pneumatic picking mechanism in which the pressurized fluid is provided by a second cylinder whose piston is driven by the loom main shaft. With this arrangement, however, the pressure in the shuttle driving cylinder cannot be built up rapidly enough.
It is therefore an object of the present invention to provide a pneumatic shuttle picking mechanism in which the piston can be subjected to the full pressure prevailing in the reservoir without major losses and within a very short time, and which ensures that the piston returns to its starting position.
SUMMARY OF THE INVENTION
In accordance with the principles of the present invention, the above and other objectives are realized in a pneumatic shuttle picking mechanism in which a main valve is used to control the feeding of pressurized gas from a reservoir to the cavity of the piston supporting cylinder and wherein the valve includes a valve seat, a valve guide and a valve member in the form of a slidably mounted valve disk adapted to bear against the valve seat when the main valve is in the closed position. The valve disk is provided with a valve stem slidably supported in the valve guide and the valve disk is further formed as a cup-shaped member with a hollow rear side so that the annular rim of the aforesaid rear side bears substantially fluid-tightly against the outer periphery of the valve guide to thereby form a chamber between the rear side of the valve disk and the front side of the valve guide. The volume of the latter chamber varies in accordance with the movement of the valve disk and reaches a maximum when the main valve is in a closed position.
The picking mechanism is further provided with an auxiliary valve which is slidably mounted in a through-bore of the valve stem. The auxiliary valve provides communication in its forward position, via the through-bore in the valve stem, between the chamber and the reservoir and, in its rear position, between the chamber and the cylinder cavity. Furthermore, it is arranged such that when the main valve is closed and the piston in the cylinder is in its rearward position, the valve is urged rearwardly by the piston away from the piston to thereby connect the chamber and the cylinder cavity.
A control valve is additionally provided in the mechanism for controlling the movement of the valve disk. The control valve provides coupling with a control port which is located at the transition from the valve seat to the cylinder cavity. The control port is coupled by the control valve with the reservoir to open the main valve and thereby cause striking of the shuttle, or is coupled with a source of gas under a pressure substantially lower than the operating pressure prevailing in the reservoir to close the main valve and thereby cause braking of the shuttle, or with a vacuum source to return the piston to its initial position with the main valve in its closed position.
Preferably the valve seat is made conical and the valve disk is provided with a matching conical annular region. An O-ring may be inserted into a groove in the valve seat for sealing purposes.
The auxiliary valve is preferably spindle-shaped and comprises a stem with an enlargement preferably provided with an O-ring in its middle. The O-ring bears against the inner wall of the longitudinal through-bore in the valve disk stem. Connecting openings from the chamber on the rear side of the valve disk terminate in the aforesaid longitudinal through-bore. Depending on its position, the auxiliary valve opens the path from the connecting openings rearwardly into the reservoir or forwardly into the cylinder cavity. For better guidance and for limiting the axial motion of the spindle in the through-bore, a further enlargement is provided at the rear end of the stem. This latter enlargement is provided with longitudinal bores in order to ensure communication between the connecting openings and the reservoir.
The valve guide has a central bore for guiding the hollow valve disk stem. As above indicated, the annular rim of the hollow rear side of the valve disk bears against the outer periphery of the valve guide so as to form a chamber between the valve guide and the rear side of the valve disk. The pressure prevailing in this chamber depends on the position of the auxiliary valve and contributes to the control of the main valve.
The control valve communicates with the reservoir and, through the control port, with the forward region of the valve seat, so that with the main valve closed there is still communication with the cylinder cavity. The control valve selectively connects the control port with the reservoir or with a source of pressurized gas which supplies a gas at relatively low superatmospheric pressure, the so-called braking pressure of, for example, 0.2 bar, or with a vacuum source of, for example, 0.2 bar. In addition, the reservoir is constantly connected with a source of pressurized gas for providing the so-called operating pressure, which is adjustable and may have a level of, for example, 4 bar superatmospheric.
The terms "superatmospheric" and "subatmospheric" or "vacuum" as used herein designate the pressure difference from ambient (atmospheric) pressure. The cylinder cavity is vented on the front side to the environment, so that the piston face is exposed to atmospheric pressure.
The pneumatic shuttle picking mechanism is controlled such that in the starting position of the piston the control port of the control valve is connected to the vacuum source so as to hold the piston in its starting position by the subatmospheric pressure. Thereby, the piston urges the auxiliary valve rearwardly so that subatmospheric pressure prevails at the connecting openings in the chamber, and also in the chamber itself. Hence, by this pressure differential, the main valve is held in closed position.
In order to pick the shuttle, the control valve connects the control port to the reservoir so as to expose the front side of the valve disk and the piston to operating pressure. Since this pressure is balanced through the relatively fine connecting openings, the chamber is still under vacuum, while the forward side of the valve disk is being subjected to operating pressure. As a result, the valve disk is urged rearwardly, i.e. the main valve opens and the piston is driven forwardly by the pressurized gas maintained at operating pressure. Movement of the piston thereby shoots the shuttle through the shed. Owing to its inertia the auxiliary valve does not follow or at most, partially follows the motion of the valve disk.
The front side of the valve disk is exposed to the operating pressure for only a very short moment--a fraction of a second--and the main valve opens in about 0.1 second. The pressure built up in the cylinder cavity then drives the piston forward and catapults the shuttle.
In order to be able to catch or brake the returning shuttle, the control port of the control valve is now connected to a source of braking pressure which is substantially lower than the operating pressure. This causes the main valve to close, i.e. the valve disk moves forwardly and bears against the valve seat. The auxi.liary valve follows this movement, since it is subject to the same pressure differential, so that the forward end of the auxiliary valve now extends into the cylinder cavity. The chamber now reaches its maximum volume and is under operating pressure, because the openings connecting the chamber to the reservoir are open.
The level of the braking pressure is so selected that the piston can catch the arriving shuttle within the piston stroke. At the rear end of the piston stroke, the piston contacts the auxiliary valve and urges it rearwardly. Thereby, the connecting openings of the chamber are connected with the cylinder cavity, and the pressure in the chamber is lowered to braking pressure level. Since the rearwardly facing outer periphery of the valve disk is always exposed to operating pressure, the main valve is further held in its closed position.
In order to hold the piston in place after it has reached its rear end position, the control port of the control valve is connected with the vacuum source after braking has been completed. In the event that the braking process does not bring the piston to its rearward end position, it is now drawn to and held in said position by the subatmospheric pressure, since the front face of the piston is subjected to atmospheric pressure. Through the connecting openings the subatmospheric pressure or vacuum also spreads into the chamber. At this point, the operating cycle of the pneumatic picking mechanism is terminated. To begin the next operating cycle, the control port of the control valve is again connected to the reservoir.
The position to which the piston is returned by the kinetic energy of the shuttle as it is braking is not precisely defined. It depends on the friction between the shuttle and the warp yarns which is subject to variations. In general, the piston, will, therefore, be moved into its rearward end position by the vacuum applied in the last operating step. In order to have the full piston stroke available as an acceleration path for shuttle picking, means are preferably provided for carrying the shuttle along during the return motion of the piston and thus to also return it to its rear end position. For this purpose, a catch hook is provided at the tip of the piston rod. This hook is lifted in the forward end position of the piston, thereby releasing the shuttle.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other features and aspects of the present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings, in which:
FIG. 1 shows a sectional view of the picking mechanism, in the starting position, and with its main valve closed;
FIG. 2 shows in sectional view, the picking mechanism at the start of piston movement, and with its main valve open;
FIG. 3 shows in sectional view the picking mechanism with its piston in the forward end position and its main valve closed in preparation for the braking;
FIG. 4 shows in sectional view the picking mechanism during braking and with its main valve closed;
FIG. 5 shows a detailed section through the picking mechanism;
FIG. 6 shows the front end of the piston rod of the picking mechanism of FIG. 1 with a catch hook holding the shuttle;
FIG. 7 shows the piston rod, catch hook, and shuttle during acceleration; and
FIG. 8 shows the piston rod in its forward end position with the catch hook lifted and shuttle released.
DETAILED DESCRIPTION
The pneumatic shuttle picking mechanism of the invention comprises a cylinder 1, a main valve 2, a reservoir 3 for gas under operating auxiliary valve 5. The cylinder 1 defines an enclosed cavity 6 in which a piston 7 and a piston rod 8 are supported for reciprocating motion. The front end of the cylinder cavity 6 communicates with the outside through an aperture 9. A buffer 31, one embodiment of which is shown in FIGS. 6 to 8, connects the front end of the piston rod 8 to a shuttle 10.
The rear end of the cylinder 1 is directly followed by a valve seat 11 of the main valve 2. The main valve 2 further includes a valve disk 12 having a valve stem 13, an annular rim 14, and a valve guide 15. The valve guide 15 has a cylindrical surface and is arranged rearwardly of the valve seat 11 and co-axially with respect to the cylinder 1. The valve guide also has a central guide bore 16 in which the valve stem 13 is supported. The annular axially rearwardly extending rim 14 of the valve disk 12 slides on the external side of the valve guide 15 so as to form a chamber 17 between the front side of the valve guide 15 and the rear side of the valve disk 12. The chamber 17 is closed toward the outside and is provided with connecting openings pressure, an electric control valve 4, and an 18 of, for example, 2 mm diameter, which terminate only in the front region of the hollow valve stem 13.
The valve stem 13 has an axial through-bore 19 whose forward end communicates with the cylinder cavity 6 and whose rearward end communicates with the guide bore 16 of the valve guide 15. The guide bore 16, in turn, communicates with the reservoir 3. The valve disk 12 is slidably guided on the valve guide 15, and any movement of the valve disk 12 results in a change in volume of the chamber 17. With the main valve 2 closed, i.e. when the valve disk 12 bears or seats against the valve seat 11, the volume of the chamber 17 is at its maximum. With the main valve open, this volume is at its minimum which is substantially zero. The main valve 2 is followed in the rearward direction by the reservoir 3 which may comprise a cylindrical space connected to a source of pressurized gas of, for example, 4 bar superatmospheric pressure.
The through-bore 19 of the valve stem 13 slidable supports the auxiliary valve 5. The latter valve enables communication of the connecting openings 18 of the chamber 17 with either the reservoir 3 or the cylinder cavity 6. The auxiliary valve 5 is in the shape of a spindle and comprises a stem 20. The stem 20 is provided at its middle with a disk-shaped enlargement 21 which carries an O-ring which sealingly bears against the inner wall of the bore. The movement of the auxiliary valve 5 is suitably limited by stops so that the disk-shaped enlargement 21 in the forward position of the auxiliary valve is disposed before the connecting openings 18, and in the rear end position of the auxiliary valve 5 is disposed behind the connecting openings 18. In the forward position, the stem 20 extends somewhat into the cylinder cavity 6. For better guidance, the rear end of the stem 20 can also be provided with an enlargement 22. The latter includes axial passages 23 to prevent it from having any blocking effect.
Both the valve seat 11 and the valve disk 12 have rearwardly conically flaring sealing faces. Furthermore, at the side end of the valve seat 11 an O-ring 25 is provided for sealing purposes in an annular groove in the valve seat. Into the conical sealing face of the valve seat 11 there opens rearwardly of the O-ring 25 a first conduit 26 and forwardly of the O-ring 25 a second conduit 27. The first conduit 26 establishes communication between the reservoir 3 and the control valve 4, while the second conduit connects a control port 28 with the control valve 4. Both conduits 26, 27 are so arranged that their ends are not closed by the valve disk 12 even in the closed position of the main valve 2.
This can be accomplished for the conduit 26 simply by ending the conduit at the wide end of the valve seat 11. The second conduit, however, leads to the control port 28 located at the narrow end of the valve seat 11. By making the transition from the valve seat 11 to the cylinder cavity 6 somewhat rounded, even with the main valve 2 closed, the second conduit 27 communicates with the cylinder cavity 6 through the control port 28. The control valve 4 is so designed that it is able to selectively perform the following three functions: firstly, to interconnect the first conduit 26 and the second conduit 27; secondly, to close the first conduit 26 and to connect the second conduit 27 to a source of pressurized gas which provides a braking pressure of, for example, 0.2 bar superatmospheric; and thirdly, to close the first conduit 26 and to connect the second conduit with a vacuum source of, for example, 0.2 bar.
The shuttle picking mechanism of the invention operates in three working steps. In the first step the main valve 2 is closed, the second conduit 27 is connected to a vacuum, and the piston 7 is in its rear starting position. This urges the auxiliary valve 5 rearwardly so that the connecting openings 18 communicate with the front side of the valve disk 12, thereby also placing the chamber 17 under vacuum. This condition of the picking mechanism is shown in FIG. 1. It is the starting position prior to striking or shooting of the shuttle.
In the second working step the control valve 4 connects the first conduit 26 with the second conduit 27 for a fraction of a second, e.g. 0.05 sec., so that the working pressure builds up between the valve disk 12 and the piston 7. Since the chamber 17 is still under vacuum and the operating pressure spreads through the small connecting openings 18 into the chamber 17 very slowly, the pressure at the rear face of the valve disk 12, namely that in the chamber 17, is lower than that at the front face of the valve disk 12. The valve disk is thus shifted rearwardly (to the left in FIG. 2), whereby the disk is lifted off the valve seat 11, opening the main valve 2. As a result, the chamber 17 disappears, i.e. its volume becomes substantially zero. This condition of the picking mechanism is shown in FIG. 2. Due to the opened main valve, pressurized gas can now flow rapidly through the annular space formed between valve seat 11 and valve disk 12 into the cylinder cavity 6. The piston is thereby driven forward to pick the shuttle 10. Owing to the operating pressure gradually building up in the chamber 17, the valve disk 12 moves forward only slowly. Within the short time of shuttle picking there is thus no appreciable reduction in flow cross section between the valve seat 11 and the valve disk 12. This also applies to the embodiment of the invention described in FIG. 5 in which the valve disk 12 is urged with a slight force into the closed position preferably by a compression spring 46. During the rearward movement of the valve disk 12, the auxiliary valve 5, owing to its inertia, changes its position only slightly or not at all, i.e. it moves forward relative to the valve disk 12.
As soon as the piston 7 has reached its forward end position (to the right in FIG. 3) the third working step commences. The first conduit 26 is closed and the second conduit 27 vents the operating pressure through a conduit 29 until the desired braking pressure prevails, and is connected to a source of pressurized gas supplying the braking pressure, which pressure is relatively low and may be, for example, 0.2 bar above atmospheric. The braking pressure is substantially lower than the operating pressure, so that the front face of the valve disk 12 is subject to lesser pressure than its rear face. The valve disk 12 is thus shifted towards the valve seat 11 so that the main valve 2 closes. The auxiliary valve 5 does not change its position relative to the valve disk 12, i.e. it is likewise shifted forward so that the chamber 17 is enlarged while under operating pressure. This condition of the picking mechanism is shown in FIG. 3 and, as soon as the main valve 2 is closed, the picking mechanism is able to catch and brake the returning shuttle.
The pressure cushion in the cylinder cavity 6 uniformly brakes the shuttle 10. The required braking path depends on the level of the braking pressure, on the size of the control port between the second conduit 27 and the cylinder cavity 6, and on the adustable size of the aperture 29. The braking path is selected to be as long as possible, i.e. the braking pressure is to be as low as possible so that during braking of the shuttle 10 the piston will come to a halt in the vicinity of its left-hand end position.
During the first working step of the next working cycle, the first conduit 26 again remains closed and the second conduit 27 is connected to a vacuum source supplying a vacuum of for, example, 0.2 bar. This vacuum, in turn, propagates through the control port 28 into the cylinder cavity 6 and draws the piston 7 fully into its left-hand end position or starting position, respectively, unless it has already reached it in the course of braking. In this starting position the piston 7 urges the auxiliary valve 5 rearwardly into the bore 19 of the valve stem 13, so that the connecting openings 18 are now in communication with the cylinder cavity 6. The vacuum thus also propagates into the chamber 17. As soon as the piston 7 has reached it left-hand end position, and the vacuum prevails in the chamber 17, the shuttle picking mechanism is ready for the next shuttle picking stroke.
Since in this first working step a vacuum prevails in the chamber 17, the valve disk 12 is maintained closed only due to the operating pressure acting on the annular rim 14 and the auxiliary valve 5. Therefore, the annular rim 14 should have sufficient surface area to ensure that the disk is kept closed. The actual effective area of the rim corresponds to the difference between the diameters of the O-ring 25 and the valve guide 15. The O-ring 25 may have a diameter of for example, 8.5 cm, the valve guide 15 a diameter of 6.3 cm, and the auxiliary valve 5 a diameter of 2 cm. The effective surface area is thus about 29 cm 2 , so that at an operating pressure of 4 bar the closing force corresponds to about 1200N.
The control valve 4 is activated by a transmitter included in the program unit at the loom shaft. For individual picking operations, manual actuation is also contemplated. Between the control valve 4 and the vacuum source, a negative pressure valve is provided. This valve is actuated by the position transmitter of the shuttle box. Furthermore, between control valve 4 and the source providing the braking pressure there is provided a braking valve which is likewise activated by the position transmitter of the shuttle box. Since the timed sequence of programming the control valve, the negative pressure valve, and the braking valve is so selected that the pneumatic shuttle picking mechanism shoots off the shuttle at substantially the same instant as a mechanical picking drive, it is familiar to those of skill in the art and need not be described in detailed herein.
In order to attain a high degree of acceleration of the shuttle 10 by the piston 7 it is important to allow the pressurized gas contained in the reservoir 3 to flow substantially unimpeded into the cylinder cavity 6 and thereby to subject the piston 7 to the full operating pressure. To this end, the main valve 2 should have a very short length of construction, and the surface area of the annular chamber formed between valve seat 11 and valve disk 12 in open condition of the main valve 2 should be sufficiently large to minimize the flow resistance. At the same time gas should be able to flow from the reservoir 3 to the cylinder cavity 6 without any major directional change. These requirements can best be met if the cone angle of the valve seat 11 and of the valve disk 12 ranges between 30 degrees and 45 degrees. With a smaller angle the valve disk 12 must travel an excessively long path to open up a sufficiently large annular chamber for pressurized gas flow. At a wider angle pressure losses occur due to the two changes in the direction of flow of pressurized gas into the cylinder cavity 6.
FIG. 5 shows the details of a preferred embodiment of the invention. At the junctions of cylinder 1, main valve 2, and reservoir 3, O-rings 40 are provided for sealing purposes. In the interior of the annular rim 14, a collar 41, and in the guide bore 16, a collar 42 are provided to effectively seal the chamber 17 against the reservoir 3. In the front face of the valve guide 15 an O-ring 43 is seated in a groove to cushion the impact of the valve disk 12 against the valve guide 15. The auxiliary valve 5 is guided in an annular insert 44 whose inner diameter corresponds to the enlargement 21 of the auxiliary valve 5, and which tapers in front to the diameter of the stem 20 to guide the latter. In the tapering portion of the insert 44, bores are provided to avoid obstruction of the connection between the chamber 17 and the cylinder cavity 6 when the auxiliary valve 5 is in its rearward position.
The rear end of the stem 20 has an enlargement 22 which slides in the bore 19 and which has axial passages 23. The forward end position of the auxiliary valve 5 is defined by the abutment of the enlargement 22 against the insert 44 where an O-ring 45 is interposed to cushion the impact. A compression spring 46 is seated against a rearwardly opening stepped enlargement of the diameter of the bore 19 in the valve stem 13. The other end of the compression spring 46 is seated on a guide pin 47 mounted by a spring ring 48 at the rear end of the guide bore 16.
The compression spring 46 is not essential to the function of the picking mechanism--it merely facilitates operation of the assembly and defines the position of the valve disk 12 in non-pressurized condition. In the embodiment of FIG. 5, the front end of the compression spring 46 also serves as an abutment to define the rear end position of the auxiliary valve 5. To this end an O-ring 49 is interposed between the enlargement 22 and the compression spring 46.
FIGS. 6 to 8 show a device by which the forward end of the piston rod 8 is fixedly connected to the shuttle 10 as long as the piston 7 is not in its forward end position. This enables the piston 7, in the first working step when the piston is drawn rearwardly by the vacuum prevailing in the cylinder cavity 6, to take along the shuttle 10. This connecting device comprises a catch hook 30 mounted at the forward end of the piston rod 8. Furthermore, the forward end of the piston rod 8 carries a buffer 31 engaging the shuttle 10.
The catch hook 30 is linked to the piston rod somewhat above the buffer 31 and engages a recess 32 in the shuttle which accommodates the shuttle rollers 33. The leading end of the catch hook 30 enters the recess 32 with its lower position and is provided in its upper position with a roller 34. The roller 34 slides along a rail 35 arranged parallel to and spaced above the shuttle path. The rail 35 has a rubber covering 36 along which the roller 34 slides so that the catch hook 30 is elastically urged downwardly and cannot fall out of the recess 32 in the shuttle 10.
In the forward end position of the picking mechanism, the catch hook 30 must release the shuttle 10 in order to enable it to carry the weft thread through the shed. Hence, in the forward end position the catch hook 30 must be lifted. This is accomplished by a control cam 37 which reaches underneath the sliding roller 34 and forces the sliding roller into a higher path to thereby lift the catch hook 30.
By means of the catch hook 30 the tip of the piston rod 8 and the shuttle 10, except in the forward end region, are firmly connected during the entire piston stroke. In this way, it is possible by retraction of the piston 7 to also return the shuttle 10 to the rear starting position for shuttle picking.
An advantage of the pneumatic shuttle picking mechanism of the invention is that it creates relatively low noise. While in a loom for weaving paper-machine screens with mechanical shuttle picking the noise level is about 90 dB(A), it can be reduced to about 82 dB(A), by the use of pneumatic shuttle picking of the invention.
In all cases, it is understood that the above-described arrangements are merely illustrative of the many possible specific embodiments which represent applications of the present invention. Numerous and varied other arrangements can be readily devised without departing from the spirit and scope of the invention.
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A pneumatic picking mechanism for weaving shuttles wherein the weaving shuttle is driven by a piston moved in a cylinder cavity by pressurized gas and wherein the pressurized gas is supplied from a reservoir through a main valve to the cylinder cavity and the main valve is controlled via a control valve assisted by an auxiliary valve.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a non-reduced dielectric composition, which may be used for dielectric materials, such as monolithic ceramic capacitors, using base metals such as nickel as an internal electrode material.
2. Description of the Related Art
Conventional dielectric ceramic materials containing BaTiO 3 as a main component exhibit semiconductive properties when they are reduced as a result of firing under a neutral or reducing low oxygen partial pressure. Therefore, materials which do not melt at the high temperature at which the dielectric ceramic material is sintered, and which do not oxidize when fired under a high oxygen partial pressure and change the dielectric ceramic material to the semiconductor, for example noble metals such as palladium and platinum, must be used for the internal electrodes. Such problems significantly have hampered the low-cost production of the monolithic ceramic capacitors.
In order to solve the above problem, the use of base metals such as nickel, for example, has been required in internal electrode materials. When such base metals are used as internal electrode materials and fired under conventional conditions, the electrode materials become oxidized and do not accomplish the desired function as electrodes. For use with such base metals as internal electrode materials a dielectric ceramic material has been required which does not cause a change into a semiconductor state even when fired under a neutral or reducing low oxygen partial pressure, and which has the sufficient specific resistance and excellent dielectric characteristics of a dielectric material for a capacitor.
As dielectric ceramic materials satisfying the above conditions, for example, a BaTiO 3 --CaZrO 3 --MnO--MgO composition in JP-A-62-256422, a BaTiO 3 --MnO--MgO-rare earth metal oxide composition in JP-A-63-103861, and a BaTiO 3 --(Mg, Zn, Sr, Ca)O+Li 2 O--SiO 2 --MO (wherein MO represents BaO, SrO, or CaO) in JP-B-61-14610 are proposed.
However, the non-reduced dielectric ceramic composition disclosed in JP-A-62-256422 tends to form different phases including CaZrO 3 and CaTiO 3 during firing step, and Mn.
In the non-reduced dielectric ceramic composition disclosed in JP-A-63-103861, the dependency of the insulation resistance and capacitance on temperature are significantly affected by the particle size of the main component, BaTiO 3 , so that the process of obtaining stable characteristics is hard to control. Moreover, the product (CR) of the insulation resistance and electrostatic capacitance ranges from 1,000 to 2,000 (Ω.F).
Further, in the composition disclosed in JP-B-61-14610, the dielectric constant of the resulting dielectric ceramic ranges from 2,000 to 2,800, which is lower than that of conventional ceramic compositions using noble metals such as palladium, i.e., 3,000 to 3,500. Thus, the substitution of this composition for conventional materials, for the purpose of the cost reduction, is not favorable to the miniaturization of a capacitor with higher capacitance.
Although all of the non-reduced dielectric ceramic compositions, including the above-mentioned compositions, which have been proposed recently have higher insulation resistances at room temperature compared with conventional materials, the resistance tends to drastically decrease at a higher temperature. Therefore, the resistance against high temperature is low, and that causes difficulty in thinning of the dielectric substance, so no thin multilayer capacitor using a non-reduced dielectric ceramic composition has been realized. Further, conventional non-reduced dielectric ceramic compositions exhibit a low resistance against high humidity in comparison with conventional materials using palladium as the internal electrode.
The present inventors have proposed novel non-reduced dielectric ceramic compositions in JP-A-5-09066, JP-A-5-09067, and JP-A-5-09068 in order to solve the above problems. Demands for compositions having further excellent properties have increased depending on properties required in the market, in particular, at a high temperature and high humidity.
SUMMARY OF THE INVENTION
In accordance with the present invention, it is intended to provide a non-reduced dielectric ceramic composition applicable to thin layer use, which can be fired without a structural change to a semiconductor under a low oxygen partial pressure, which has a dielectric constant of 3,000 or more and insulation resistance 6,000 or more by CR product, and which has excellent resistance against high temperature and moisture. Further, in the ceramic composition of the present invention, the change of capacitance is fixed within ±15% over the range of -55° C. to 125° C. when the capacitance at 25° C. is set to the standard.
The non-reduced dielectric ceramic composition in accordance with the present invention is characterized in that the composition contains a main component including BaTiO 3 , at least one rare earth metal oxide (Re 2 O 3 ) selected from the group consisting of Tb 2 O 3 , Dy 2 O 3 , Ho 2 O 3 and Er 2 O 3 , and Co 2 O 3 , wherein such constituents are contained in predetermined amounts in the main component, an sub-component including BaO, MnO, MgO, and at least one compound selected from the group consisting of NiO and Al 2 O 3 , and an oxide glass mainly containing Li 2 O--(Si x Ti 1-x )O 2 --M, wherein M is at least one compound selected from the group consisting of Al 2 O 3 and ZrO 2 , and the range of X is 0.30≦X≦1.00.
By mixing these compounds according to a predetermined formulation optimally selected, the non-reduced dielectric ceramic composition of the present invention can be fired without changing to a semiconductor structure even under a low oxygen partial pressure. The ceramic composition has a dielectric constant 3,000 or more and an insulation resistance of 6,000 or more expressed by CR. Further, the change of capacitance is satisfactorily minimized within ±15% over -55° C. to 125° C. when the capacitance at 25° C. is set to the standard that satisfies X7R characteristic defined in EIA. Moreover, the ceramic composition has excellent resistance against high temperature and moisture, and is applicable to thin layer use.
Accordingly, when the non-reduced dielectric ceramic composition of the present invention is used as a dielectric material for multilayer semiconductor capacitors, base metals such as nickel, can be used as an internal electrode material. Thus, a significant cost reduction in such capacitors can be achieved compared with capacitors using a noble metal, for example, palladium, without decreases in all the characteristics including resistance against high temperature and moisture.
Preferred contents of BaTiO 3 , the rare earth metal oxide (Re 2 O 3 ), and Co 2 O 3 as main components in the non-reduced dielectric ceramic composition range from about 92.0 to 99.4 mole percent for BaTiO 3 , about 0.3 to 4.0 mole percent for Re 2 O 3 , and about 0.3 to 4.0 mole percent for Co 2 O 3 to total 100 mole percent of the main components. More preferably, the respective amounts are about 94.0 to 99.0%, about 0.5 to 2.5% and about 0.5 to 4.0%. It was experimentally confirmed that this composition achieves a high insulation resistance, high dielectric constant, and stability of capacitance over wide temperature range.
Since a content of BaTiO 3 of less than 92.0 mole percent causes the increased contents of the rare earth metal oxide and Co 2 O 3 in the composition, the insulation resistance and dielectric constant unsatisfactorily decrease. On the other hand, when the BaTiO 3 content exceeds 99.4 mole percent, the addition of the rare earth metal oxide and Co 2 O 3 has little effect, and the temperature-capacitance change at a high temperature near the Curie point drastically shifts toward the plus side.
The contents set forth above in the present invention may include other ranges in which high insulation resistance, high dielectric constant, stability of capacitance over the wire temperature renege are achieved.
The preferred content of BaO as the sub-component ranges from about 0.05 to 4.0 mole percent, more preferably about 0.05 to 3.0%, based on to 100 mole percent of the main components in the non-reduced dielectric ceramic composition. It was experimentally confirmed that this composition achieved a reduction of the dielectric loss tan δ and insulation resistance, and completeness of sintering. When the content is less than 0.05 mole percent, stable characteristics are not obtainable in a given sintering atmosphere resulting in the increase in tan δ and decrease in the insulation resistance. On the other hand, when the content exceeds 4.0 mole percent, the completeness of sintering decreases.
In the present invention, the sub-component content may include other ranges in which decrease of the dielectric loss tan δ and insulation resistance, and increase of completeness of sintering, are achieved.
Further, the preferred content of MnO as the sub-component ranges from about 0.05 to 2.0 mole percent, more preferably about 0.05 to 1.5%, based on 100 mole percent of the main components in the non-reduced dielectric ceramic composition. It was experimentally. confirmed that this composition achieved a decrease of insulation resistance, increase of resistance against high temperature and moisture. A MnO content of less than 0.05 mole percent causes an unsatisfactory decrease in the insulation resistance, whereas a content over 2.0 mole percent causes some decrease in the insulation resistance and shortening of mean time to failure (MTTF).
In the present invention, the content of the sub-component MnO may include other ranges in which the component achieve the decrease of insulation resistance, increase of resistance against high temperature and moisture.
Moreover, the preferred content of MgO as the sub-component ranges from about 0.5 to 5.0 mole percent, more preferably about 1.0 to 4.0%, based on 100 mole percent of the main components in the non-reduced dielectric ceramic composition. It was experimentally confirmed that this component achieved stability of capacitance within the wide temperature range, increase of dielectric constant, and decrease of insulation resistance. When the MgO content is less than 0.5 mole percent, the stability of capacitance over the wide temperature range is not guaranteed. In particular, the decrease of capacitance is large in the low temperature range. Further, the increase of insulation resistance is small. On the other hand, a content over 5.0 mole percent causes decreases in the dielectric constant and insulation resistance.
In the present invention, the content of the sub-component MgO may include other ranges in which the component achieve a decrease of insulation resistance, increase of resistance against high temperature and moisture.
Also, it is preferred that 0.3 to 3.0 mole percent of at least one of NiO and Al 2 O 3 sub-components is present, more preferably about 0.5 to 2.0%, based on 100 mole percent of the main components in the non-reduced dielectric ceramic composition in accordance with present invention. By the addition of these component an increase of the insulation resistance and dielectric constant, and decrease of dielectric loss were achieved.
When adding less than 0.3 mole percent of these components, the insulation resistance decrease and MTTF is shortened since the resistance against reducing atmosphere decreases. On the other hand, a NiO addition exceeding 3.0 mole percent causes a decrease in the insulation resistance similar to MnO addition, and the Al 2 O 3 addition over 3.0 mole percent causes a decreased insulation resistance due to the incompleteness of sintering with increased dielectric loss.
In the present invention, the content of the sub-components NiO and/or Al 2 O 3 may include other ranges in which the component achieve the decrease of insulation resistance, increase of dielectric constant and decrease of dielectric loss.
In the non-reduced dielectric ceramic composition of the present invention, the alkaline metal oxide content, contained in the BaTiO 3 as impurities, is preferably about 0.04 weight percent or less, based on the experimental results on the increase in the dielectric constant. An alkaline metal oxide content over 0.04 weight percent in BaTiO 3 is impractical due to the decreased dielectric constant.
However, in the present invention, the content of the alkaline metal oxides may include other ranges in which the dielectric constant is increased.
Further, the present invention is characterized by that the non-reduced dielectric ceramic composition may also contain BaZrO 3 as an sub-component. By mixing such a component according to a predetermined formulation optimally decided, the non-reduced dielectric ceramic composition of the present invention can be fired without changing to a semiconductor structure even under a low oxygen partial pressure. The ceramic composition has a dielectric constant of 3,000 or more and insulation resistance of 7,000 or more expressed by CR. Further, the capacitance change is restricted within ±15% over -55° C. to 125° C. when the capacitance at 25° C. is set to the standard that satisfies X7R characteristic defined in EIA. Moreover, the ceramic composition has excellent resistance against high temperature and moisture, and is applicable to thin layer components.
Accordingly, when the non-reduced dielectric ceramic composition of the present invention is used as the dielectric material of multilayer semiconductor capacitors, base metals such as nickel can be used as an internal electrode material. Thus, significant cost reduction can be achieved in such capacitors, compared with capacitors using a noble metal, for example, palladium, without decreases of resistance against high temperature and moisture.
In the non-reduced dielectric ceramic composition of the present invention, about 0.3 to 4.0 mole percent of BaZrO 3 is preferably present, more preferably about 0.5 to 3.0%, based on 100 mole percent of main components comprising a given amount of BaTiO 3 , at least one rare earth element (Re 2 O 3 ) selected from the group consisting of Tb 2 O 3 , Dy 2 O 3 , Ho 2 O 3 , and Er 2 O 3 , and Co 2 O 3 , based on the experimental results on the increased insulation resistance, and stability of capacitance in the wide range of the temperature. A BaZrO 3 content of less than 0.3 mole percent causes less increase in the insulation resistance. On the other hand, a content over 4.0 mole percent causes the noticeable decrease of the capacitance at high temperature region, although the insulation resistance is further increased.
In the present invention, the content of the BaZrO 3 sub-component may include other ranges in which the component achieves an increase of insulation resistance and stability of capacitance in the wide temperature range.
The preferred content of oxide glass set forth above is about 0.5 to 2.5 weight percent per 100 weight percent of the above-mentioned sub-component, preferably about 0.5 to 2.0 wt % in the non-reduced dielectric ceramic composition of the present invention. It was experimentally confirmed that this content causes an increase of completeness of sintering, reducing resistance and dielectric constant. An oxide glass content of less than 0.5 weight percent decreases the completeness of sintering and little increase in the reducing resistance. A content exceeding 2.5 weight percent is impractical due to a decreased dielectric constant.
In the present invention, the glass oxide content may include other ranges in which the component achieves the completeness of sintering, high resistance against reduction and high dielectric constant.
The mole percent of the oxide glass is preferably included within the range of the hexagon, inclusive of sides, having vertices A(20,80,0), B(10, 80, 10), C(10, 70, 20), D(35, 40, 20), E(45, 45, 10), and F(45, 55, 0) expressed by the ternary diagram consisting of (Li 2 O, (Si x Ti 1-x )O 2 , M), wherein 0.30≦X≦1.00 in the composition on line F-A. It was experimentally confirmed that the oxide glass content caused the increase of completeness of sintering and increase of resistance against high temperature and moisture.
A composition out of the range set forth above causes an unsatisfactory decrease in completeness of sintering because the composition does not form glass even when quenched with iced water. Further, even if the composition is within the glass forming range set forth above, a composition corresponding to the line F-A where X=1.00 is not suitable since most characteristics are lost at a high temperature and high humidity. Moreover, an X of less than 0.3 does not form glass and thus decreases completeness of sintering.
However, in the present invention, such glass oxide content range may include other ranges in which the component achieves the completeness of sintering, high resistance against reduction and high dielectric constant.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a ternary diagram consisting of Li2O--(Si x Ti 1-x )O 2 --M wherein M is at least one member selected from the group consisting of Al 2 O 3 and ZrO 2 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following non-limiting Examples illustrate the non-reduced dielectric ceramic composition in accordance with the present invention.
EXAMPLE 1
As starting materials, BaTiO 3 containing various levels of alkaline metal oxide impurities; Tb 2 O 3 , Dy 2 O 3 , Ho 2 O 3 and Er 2 O 3 as rare earth oxides (Re 2 O 3 ); Co 2 O 3 ; BaCO 3 ; MnCO 3 ; MgO; NiO and Al 2 O 3 ; and oxide glass were weighed so as to obtain the compositions shown in Tables 1 and 2, where BaTiO 3 containing 0.03 weight percent of alkaline metal oxides was used in each sample except for Sample Nos. 34 and 35 in which the alkaline metal oxide contents in the BaTiO 3 used were 0.05 and 0.07 weight percent, respectively.
TABLE 1__________________________________________________________________________Sample BaTiO.sub.3 Re.sub.2 O.sub.3 Co.sub.2 O.sub.3 BaO MnO MgO NiO,Al.sub.2 O.sub.3 GlassNo. (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (Wt. %)__________________________________________________________________________ 1 97.0 Dy.sub.2 O.sub.3 1.5 1.5 1.5 0.3 1.0 NiO 1.0 1.0 2 99.0 Dy.sub.2 O.sub.3 0.5 0.5 1.5 0.3 1.0 NiO 1.0 1.0 3* 99.6 Dy.sub.2 O.sub.3 0.2 0.2 1.5 0.3 1.0 NiO 1.0 1.0 4* 90.0 Dy.sub.2 O.sub.3 4.0 6.0 1.5 0.3 1.0 NiO 1.0 1.0 5 94.0 Dy.sub.2 O.sub.3 2.0 4.0 1.5 0.3 1.0 NiO 1.0 1.0 6 97.5 Ho.sub.2 O.sub.3 1.5 1.0 1.5 0.3 2.0 NiO 1.0 1.0 7 96.5 Ho.sub.2 O.sub.3 1.5 2.0 0.1 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 8 96.5 Ho.sub.2 O.sub.3 1.5 2.0 0.05 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 9* 96.5 Ho.sub.2 O.sub.3 1.5 2.0 0.03 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.010 96.5 Ho.sub.2 O.sub.3 1.5 2.0 3.0 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.011 96.5 Ho.sub.2 O.sub.3 1.5 2.0 4.0 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 12* 96.5 Ho.sub.2 O.sub.3 1.5 2.0 5.0 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.013 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 1.5 3.0 NiO 0.5 1.514 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 2.0 3.0 NiO 0.5 1.5 15* 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 2.5 3.0 NiO 0.5 1.516 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 0.05 3.0 NiO 0.5 1.5 17* 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 0.03 3.0 NiO 0.5 1.5 18* 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 NiO 0.2 1.519 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 NiO 2.0 1.520 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 NiO 3.0 1.5 21* 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 NiO 3.5 1.5 22* 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 Al.sub.2 O.sub.3 3.5 1.523 96.5 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 24* 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 0.2 Al.sub.2 O.sub.3 1.5 2.0 25* 96.0 Dy.sub.2 O.sub.3 1.5 1.5 1.5 0.3 0.4 Al.sub.2 O.sub.3 1.5 2.0__________________________________________________________________________
TABLE 2__________________________________________________________________________Sample BaTiO.sub.3 Re.sub.2 O.sub.3 Co.sub.2 O.sub.3 BaO MnO MgO NiO,Al.sub.2 O.sub.3 GlassNo. (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (Wt. %)__________________________________________________________________________26 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 3.0 NiO 1.5 2.027 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 4.0 NiO 1.5 2.028 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 5.0 NiO 1.5 2.029* 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 6.0 NiO 1.5 2.030 96.5 Ho.sub.2 O.sub.3 2.0 1.5 1.5 0.5 2.0 NiO 1.0 2.531* 96.5 Ho.sub.2 O.sub.3 2.0 1.5 1.5 0.5 2.0 NiO 1.0 3.032 96.5 Ho.sub.2 O.sub.3 2.0 1.5 1.5 0.5 2.0 NiO 1.0 0.533* 96.5 Ho.sub.2 O.sub.3 2.0 1.5 1.5 0.5 2.0 NiO 1.0 0.334* 97.0 Dy.sub.2 O.sub.3 1.5 1.5 1.5 0.3 1.0 NiO 1.0 1.035* 97.0 Dy.sub.2 O.sub.3 1.5 1.5 1.5 0.3 1.0 NiO 1.0 1.036* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.037* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.038* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.039* 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.040* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.041* 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.042 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.043* 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.044 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.045* 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.0__________________________________________________________________________
In each sample, the oxide glass was prepared as follows:
First, Li 2 O, SiO 2 , TiO 2 , Al 2 O 3 , and ZrO 2 were prepared as raw materials. After these raw materials were weighed so as to obtain compositions shown in Tables 3 and 4, pure water was added to the weighed materials. The materials were dispersed in water using a ball mill and PSZ balls. After removing the water to dryness, the powder mixture was placed into a platinum crucible and heated at 1400° C. for 15 minutes in a glass furnace. The melt was taken out from the crucible, and quenched in iced water to obtain a bulk glass. After the bulk glass was roughly crushed in a mortar, the crushed glass was thoroughly water-ground in the ball mill using PSZ and a dispersant. The glass powder was obtained by evaporating the dispersant to dryness.
TABLE 3______________________________________Sam- Li.sub.2 O (Si.sub.x Ti.sub.1-x)O.sub.2 M Al2O3 ZrO.sub.2ple (mol (mol x (mol (mol (molNo. %) %) (Mol Frac.) %) %) %)______________________________________ 1 20 80 0.90 0 -- -- 2 20 80 0.90 0 -- -- 3 20 80 0.90 0 -- -- 4 10 80 0.60 10 50 50 5 10 80 0.60 10 50 50 6 10 80 0.60 10 50 50 7 10 70 0.30 20 100 0 8 10 70 0.30 20 100 0 9 10 70 0.30 20 100 010 35 45 0.50 20 0 10011 35 45 0.50 20 0 10012 35 45 0.50 20 0 10013 45 45 0.50 10 50 5014 45 45 0.50 10 50 5015 45 45 0.50 10 50 5016 45 55 0.90 0 -- --17 45 55 0.90 0 -- --18 45 55 0.90 0 -- --19 20 70 1.00 10 70 3020 20 70 1.00 10 70 3021 20 70 1.00 10 70 3022 20 70 1.00 10 70 3023 20 70 1.00 10 70 3024 20 70 1.00 10 70 3025 30 60 0.60 10 30 70______________________________________
TABLE 4______________________________________Sam- Li.sub.2 O (Si.sub.x Ti.sub.1-x)O.sub.2 M Al2O3 ZrO.sub.2ple (mol (mol x (mol (mol (molNo. %) %) (Mol Frac.) %) %) %)______________________________________26 30 60 0.60 10 30 7027 30 60 0.60 10 30 7028 30 60 0.60 10 30 7029 30 60 0.60 10 30 7030 30 60 0.60 10 30 7031 40 50 0.30 10 50 5032 40 50 0.30 10 50 5033 40 50 0.30 10 50 5034 40 50 0.30 10 50 5035 40 50 0.30 10 50 50 36* 40 50 0.20 10 50 50 37* 10 85 0.90 5 50 50 38* 5 75 0.90 20 50 50 39* 20 55 0.90 25 50 50 40* 45 40 0.90 15 50 50 41* 50 45 0.90 5 50 5042 25 75 0.90 0 -- -- 43* 25 75 1.00 0 -- --44 35 65 0.90 0 -- -- 45* 35 65 1.00 0 -- --______________________________________
The oxide glass prepared in such a way contains at least one component among Li 2 O, (Si x Ti 1-x )O 2 (wherein 0.30≦X≦1), and M (wherein M represents Al 2 O 3 and/or ZrO 2 ) as shown in a ternary diagram of FIG. 1. In FIG. 1, the shaded hexagonal portion represents the range of the present invention, wherein Points A (20, 80, 0), B(10, 80, 10), C(10, 70, 20), D(35, 45, 20), E(45, 45, 10), and F(45, 55, 0) represents vertices of the hexagon.
A raw slurry was prepared by dispersing and mixing each component shown in Tables 1 and 2 with a dispersant in the ball mill using PSZ balls. After adding an organic binder and plasticizer to the slurry, the mixture was thoroughly stirred. The mixture was shaped into a ceramic green sheet having a thickness of 12 mm by the doctor blade method.
A Ni conductive paste was screen-printed on a single side of the resulting ceramic green sheet to form an internal electrode. After drying, a plurality of ceramic green sheets were laminated and pressed in the vertical direction of the sheets to obtain a laminated product. Green ceramic units were prepared by cutting the laminated product into small pieces. After each green ceramic unit was held at 320° C. for 5 hours to remove the binder in the green ceramic unit, the unit was fired at the temperature shown in Tables 5 and 6 for 2 hours in a reducing H 2 /N 2 mixed gas stream having a volume ratio of 3/100 in order to obtain a sintered dielectric element having a thickness of 8 mm.
TABLE 5__________________________________________________________________________ Firing Dielectric Dielectric Capacitance Units UnitsSample Temp. Constant Loss Change CR Product Damaged at DamagedNo. (°C.) (e.sub.25) tan δ (%) -55° C. +125° C. Cmax (Ω · F) High Temp by moisture__________________________________________________________________________ 1 1,280 3,340 1.8 -2.6 -7.8 8.9 6,480 0/36 0/36 2 1,280 3,280 1.7 -3.4 -6.4 8.1 6,710 2/36 0/36 3* 1,300 3,540 1.6 -9.1 +20.1 26.1 6,800 6/36 2/36 4* 1,280 2,910 1.9 -3.7 -8.2 9.5 1,870 21/36 19/36 5 1,280 3,240 1.7 -3.6 -7.7 9.1 6,130 0/36 1/36 6 1,280 3,350 1.8 -2.9 -7.3 8.2 6,570 0/36 1/36 7 1,280 3,260 1.9 -3.2 -7.5 8.4 6,290 1/36 0/36 8 1,280 3,190 2.1 -3.4 -7.6 8.5 6,050 2/36 1/36 9* 1,280 3,220 3.8 -3.5 -7.8 9.0 2,040 80 hrs 110 hrs10 1,300 3,340 1.9 -4.2 -7.0 7.9 6,080 1/36 3/3611 1,300 3,200 2.2 -4.6 -6.8 8.6 6,100 3/36 5/36 12* Not measurable due to unsatisfactory sintering even at 1,360° C.13 1,280 3,250 1.8 -4.9 -6.1 7.5 6,810 0/36 0/3614 1,280 3,210 1.7 -5.2 -5.8 7.1 6,360 4/36 2/36 15* 1,260 3,020 2.3 -5.6 -5.1 6.8 2,340 210 hrs 110 hrs16 1,280 3,280 1.8 -4.4 -8.4 9.5 6,480 3/36 5/36 17* 1,280 3,260 4.6 -4.8 -9.2 10.1 1,880 80 hrs 70 hrs 18* 1,280 3,100 3.2 -3.9 -7.7 8.8 3,800 270 hrs 160 hrs19 1,280 3,230 1.8 -3.8 -7.5 8.4 6,340 1/36 2/3620 1,280 3,340 1.9 -3.8 -7.9 8.7 6,180 4/36 6/36 21* 1,280 3,440 2.0 -3.6 -8.2 9.0 3,200 380 hrs 140 hrs 22* 1,320 2,780 2.8 -2.6 -5.7 6.8 4,080 240 hrs 76 hrs23 1,280 3,380 1.8 -3.1 -7.5 8.7 6,600 2/36 3/36 24* 1,260 3,140 1.8 -18.6 -13.1 18.6 3,400 30/36 26/36 25* 1,260 3,300 1.8 -12.6 -9.8 12.6 4,830 12/36 8/36__________________________________________________________________________
TABLE 6__________________________________________________________________________ Firing Dielectric Dielectric Capacitance Units UnitsSample Temp. Constant Loss Change CR Product Damaged at DamagedNo. (°C.) (e.sub.25) tan δ (%) -55° C. +125° C. Cmax (Ω · F) High Temp by moisture__________________________________________________________________________26 1,260 3,290 1.9 -5.1 -6.8 8.0 6,690 0/36 1/3627 1,260 3,210 1.8 -5.4 -6.6 7.9 7,080 2/36 2/3628 1,280 3,110 1.7 -5.6 -6.4 8.0 7,130 2/36 3/3629* 1,280 2,840 1.9 -6.1 -5.1 7.0 3,800 290 hrs 3/3630 1,260 3,200 1.7 -4.2 -8.1 9.3 6,710 0/36 0/3631* 1,260 2,610 1.6 -3.8 -9.0 10.1 6,060 3/36 1/3632 1,300 3,380 1.8 -3.7 -8.4 9.2 6,530 4/36 5/3633* 1,340 3,100 2.2 -2.9 -6.5 7.6 5,600 18/36 8/3634* 1,280 2,810 1.6 -3.0 -7.4 8.6 6,210 2/36 1/3635* 1,280 2,630 1.6 -3.1 -7.0 8.2 5,860 4/36 2/3636* Not measurable due to unsatisfactory sintering even at 1,360° C.37* Not measurable due to unsatisfactory sintering even at 1,360° C.38* Not measurable due to unsatisfactory sintering even at 1,360° C.39* Not measurable due to unsatisfactory sintering even at 1,360° C.40* Not measurable due to unsatisfactory sintering even at 1,360° C.41* Not measurable due to unsatisfactory sintering even at 1,360° C.42 1,280 3,260 1.7 -4.6 -6.6 7.6 6,240 1/36 2/3643* 1,280 3,280 1.8 -4.9 -6.2 7.1 6,180 4/36 320 hrs44 1,300 3,340 1.8 -4.0 -7.5 8.8 6,480 2/36 2/3645* 1,300 3,320 1.9 -4.2 -7.2 8.6 6,290 5/36 280 hrs__________________________________________________________________________
A laminated ceramic capacitor was made by applying a silver paste on the both end faces of the resulting sintered material and firing in air to form silver external electrodes. The laminated ceramic capacitor was evaluated by the following items: dielectric constant at a room temperature ε 25 , dielectric loss tan δ, insulation resistance (logIR), temperature-capacitance change (TCC), and weatherability, i.e., registance against high temperature and moisture. The results are summarized in Tables 5 and 6. In each sample, 36 laminated ceramic capacitors were evaluated.
The dielectric constant ε 25 , and dielectric loss tan δ was measured at 25° C., frequency of 1 KHz, and alternating voltage of 1 V. The insulation resistance was expressed as the product (CR) of the electrostatic capacitance multiplied by the result which was obtained by applying 16 V of dc voltage for 2 minutes at 25° C. The temperature-capacitance change (TCC) was evaluated with the change rate of each capacitance at -55° C. and 125° C. to the standard electrostatic capacitance at 25° C., i.e. ΔC -55 /C 25 and ΔC 125 /C 25 , and the maximum change |ΔC/C 25 | max which is absolute value of the maximum temperature-capacitance change between -55° C. and 125° C.
Concerning the weatherability evaluations, resistance against high temperature was defined as the number of damaged samples after applying 64 V of dc voltage to 36 samples at 175 ° C. for 500 hours, and in the cases where all of the samples damaged within 500 hours, its MTTF was shown in Tables 5 and 6. The resistance against moisture was evaluated by the number of damaged samples after applying dc voltage of 16 V to 36 samples at a temperature of 121° C. and humidity of 100% for 250 hours. When all of the samples were damaged within 250 hours, its MTTF was shown in Tables 5 and 6.
Tables 5 and 6 show the noticeable effects of the thin layer laminated ceramic capacitor using the non-reduced dielectric ceramic composition in accordance with the present invention, which are in no way inferior to conventional products using palladium and the like as the internal electrode.
In the Examples, a sample number marked with an asterisk (*) has a composition deferring from the specified composition in the present invention, and is out of the range of the present invention.
Then, samples with asterisk (*) will be explained.
In sample No. 4, since the BaTiO 3 content is 90.0 mole percent, the rare earth metal oxides and Co 2 O 3 contents are increased resulting in decreased insulation resistance and dielectric constant.
In sample No. 3, since the BaTiO 3 content is too high, i.e, 99.6 mole percent, there is no effect of the addition of rare earth metal oxides and Co 2 O 3 , and particularly, the capacitance change is significantly large at temperatures near the Curie point.
In sample No. 9 containing 0.03 mole percent of the BaO, the product characteristics become unstable in the firing atmosphere, resulting in the increased tan δ, and decreased insulation resistance.
Sample No. 12 containing 5.0 mole percent of BaO has incomplete sintering.
Sample No. 17 containing 0.03 mole percent of MnO has a decreased insulation resistance.
Sample 15 containing 2.5 mole percent of MnO has a shortened MTTF due to the slight decrease in the insulation resistance.
In sample Nos. 24 and 25 containing 0.2 mole percent and 0.4 mole percent of MgO, respectively, the low MgO contents do not effectively flatten the temperature-capacitance change curve, and in particular, tend to exhibit large capacitance change at the lower temperature region. Further, the insulation resistance does not noticeably increase.
In sample No. 29 containing 6.0 mole percent of MgO, the dielectric constant and insulation resistance are decreased.
In sample No. 18 containing only 0.2 mole percent of NiO, since the non-reduced properties of the texture is almost not improved, the insulation resistance is decreased and the MTTF is shortened.
In sample No. 21 containing 3.5 mole percent of NiO, the insulation resistance decreases.
In sample No. 22 containing 3.5 mole percent of Al 2 O 3 , the dielectric constant decreases with increased dielectric loss due to the decrease in sintering characteristics.
In sample Nos. 34 and 35 in which the alkaline metal oxide contents as impurities in BaTiO 3 are 0.05 and 0.07 weight percent, respectively, the dielectric constant decreases.
In sample No. 33, the oxide glass content of 0.3 weight percent causes a decrease in completeness of sintering and very little improvement in resistance against a non-reducing atmosphere.
In sample No. 31, the oxide glass content of 3.0 weight percent causes a decrease in the dielectric constant.
In sample Nos. 37 through 41, since these compositions are out of the range expressed by the hexagon formed by six points, i.e., A, B, C, D, E, and F in the ternary diagram shown in FIG. 1, the samples mostly lost transparency without changing into a glass after quenching in iced water, and this causes the decreased completeness of sintering.
Although sample Nos. 43 and 45 are included in the range expressed by the above-mentioned hexagon, these compositions are on line F-A and at the same time, X=1.00. Thus, these samples show significantly bad characteristics at a high temperature or high humidity.
In sample No. 36, since X equals to 0.20, the sample mostly lost transparency without changing into a glass. Thus, the sintering characteristics decreased in this sample.
The present invention is not limited to such a Example, and it is to be understood that modifications will be apparent to those skilled in the art without departing from the scope of the invention. For example, various sub-components can be added into the composition of the present invention without losing the above-mentioned characteristics.
EXAMPLE 2
As starting materials, BaTiO 3 containing various levels of alkaline metal oxide impurities; Tb 2 O 3 , Dy 2 O 3 , Ho 2 O 3 and Er 2 O 3 as rare earth oxides (Re 2 O 3 ); Co 2 O 3 ; BaCO 3 ; MnCO 3 ; MgO; NiO and Al 2 O 3 ; BaZrO 3 and oxide glass were weighed so as to obtain the compositions shown in Tables 7 and 8. BaTiO 3 containing 0.03 weight percent of alkaline metal oxides was used in each sample except for Sample Nos. 40 and 41 in which the alkaline metal oxide contents in BaTiO 3 used were 0.05 and 0.07 weight percent, respectively.
TABLE 7__________________________________________________________________________Sample BaTiO.sub.3 Re.sub.2 O.sub.3 Co.sub.2 O.sub.3 BaO MnO MgO NiO,Al.sub.2 O.sub.3 BaZrO.sub.3 GlassNo. (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (Wt. %)__________________________________________________________________________ 1 97.0 Dy.sub.2 O.sub.3 1.5 1.5 1.5 0.3 1.0 NiO 1.0 1.0 1.0 2 99.0 Dy.sub.2 O.sub.3 0.5 0.5 1.5 0.3 1.0 NiO 1.0 1.0 1.0 3* 99.6 Dy.sub.2 O.sub.3 0.2 0.2 1.5 0.3 1.0 NiO 1.0 1.0 1.0 4* 90.0 Dy.sub.2 O.sub.3 4.0 6.0 1.5 0.3 1.0 NiO 1.0 1.0 1.0 5 94.0 Dy.sub.2 O.sub.3 2.0 4.0 1.5 0.3 1.0 NiO 1.0 1.0 1.0 6 97.5 Ho.sub.2 O.sub.3 1.5 1.0 1.5 0.3 2.0 NiO 1.0 1.0 1.0 7 96.5 Ho.sub.2 O.sub.3 1.5 2.0 0.1 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 1.0 8 96.5 Ho.sub.2 O.sub.3 1.5 2.0 0.05 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 1.0 9* 96.5 Ho.sub.2 O.sub.3 1.5 2.0 0.03 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 1.010 96.5 Ho.sub.2 O.sub.3 1.5 2.0 3.0 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 1.011 96.5 Ho.sub.2 O.sub.3 1.5 2.0 4.0 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 1.0 12* 96.5 Ho.sub.2 O.sub.3 1.5 2.0 5.0 0.5 2.0 Al.sub.2 O.sub.3 1.0 1.0 1.013 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 1.5 3.0 NiO 0.5 2.0 1.514 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 2.0 3.0 NiO 0.5 2.0 1.5 15* 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 2.5 3.0 NiO 0.5 2.0 1.516 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 0.05 3.0 NiO 0.5 2.0 1.5 17* 97.5 Tb.sub.2 O.sub.3 1.0 1.5 1.5 0.03 3.0 NiO 0.5 2.0 1.5 18* 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 NiO 0.2 2.0 1.519 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 NiO 2.0 2.0 1.520 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 NiO 3.0 2.0 1.5 21* 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 NiO 3.5 2.0 1.5 22* 97.0 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.5 Al.sub.2 O.sub.3 3.5 2.0 1.523 96.5 Er.sub.2 O.sub.3 1.5 1.5 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 2.0 1.5 24* 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 0.2 Al.sub.2 O.sub.3 1.5 2.0 2.0 25* 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 0.4 Al.sub.2 O.sub.3 1.5 2.0 2.026 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 3.0 NiO 1.5 2.0 2.027 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 4.0 NiO 1.5 2.0 2.028 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 5.0 NiO 1.5 2.0 2.0 29* 96.0 Dy.sub.2 O.sub.3 1.5 2.5 1.5 0.3 6.0 NiO 1.5 2.0 2.030 96.5 Ho.sub.2 O.sub.3 2.0 1.5 1.5 0.5 2.0 NiO 1.0 2.0 2.5__________________________________________________________________________
TABLE 8__________________________________________________________________________Sample BaTiO.sub.3 Re.sub.2 O.sub.3 Co.sub.2 O.sub.3 BaO MnO MgO NiO,Al.sub.2 O.sub.3 BaZrO.sub.3 GlassNo. (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) (Wt. %)__________________________________________________________________________31* 96.5 Ho.sub.2 O.sub.3 2.0 1.5 1.5 0.5 2.0 NiO 1.0 2.0 3.032 96.5 Ho.sub.2 O.sub.3 2.0 1.5 1.5 0.5 2.0 NiO 1.0 2.0 0.533* 96.5 Ho.sub.2 O.sub.3 2.0 1.5 1.5 0.5 2.0 NiO 1.0 2.0 0.334 97.0 Tb.sub.2 O.sub.3 2.5 1.0 1.0 0.5 1.5 Al.sub.2 O.sub.3 1.5 3.0 1.535 97.0 Tb.sub.2 O.sub.3 2.5 1.0 1.0 0.5 1.5 Al.sub.2 O.sub.3 1.5 4.0 1.536* 97.0 Tb.sub.2 O.sub.3 2.5 1.0 1.0 0.5 1.5 Al.sub.2 O.sub.3 1.5 5.0 1.537 97.0 Tb.sub.2 O.sub.3 2.5 1.0 1.0 0.5 1.5 Al.sub.2 O.sub.3 1.5 0.5 1.538 97.0 Tb.sub.2 O.sub.3 2.5 1.0 1.0 0.5 1.5 Al.sub.2 O.sub.3 1.5 0.3 1.539* 97.0 Tb.sub.2 O.sub.3 2.5 1.0 1.0 0.5 1.5 Al.sub.2 O.sub.3 1.5 0.1 1.540* 97.0 Dy.sub.2 O.sub.3 1.5 1.5 1.5 0.3 1.0 NiO 1.0 1.0 1.041* 97.0 Dy.sub.2 O.sub.3 1.5 1.5 1.5 0.3 1.0 NiO 1.0 1.0 1.042* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.043* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.044* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.045* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.046* 97.0 Tb.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.047* 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.048 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.049* 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.050 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.051* 97.0 Er.sub.2 O.sub.3 1.0 2.0 1.5 0.5 2.0 Al.sub.2 O.sub.3 1.5 1.5 2.0__________________________________________________________________________
In each sample, an oxide glass was prepared as follows:
First, Li 2 O, SiO 2 , TiO 2 , Al 2 O 3 , and ZrO 2 were prepared as raw materials. After these raw materials were weighed so as to obtain the compositions shown in Tables 9 and 10, pure water was added to the weighed materials. The materials with water were dispersed in a ball mill using PSZ balls. After removing the water to dryness, the powder mixture was placed into a platinum crucible and heated at 1400° C. for 15 minutes in a glass furnace. The melt was taken out from the crucible, and quenched in iced water to obtain a bulk glass. After the bulk glass was roughly crushed in a mortar, the crushed glass was thoroughly water-ground in the ball mill using PSZ and a dispersant. The glass powder was obtained by evaporating the dispersant to dryness.
TABLE 9______________________________________Sam- Li.sub.2 O (Si.sub.x Ti.sub.1-x)O.sub.2 x M Al.sub.2 O.sub.3 ZrO.sub.2ple (mol (mol (mol (mol (mol (molNo. %) %) %) %) %) %)______________________________________ 1 20 80 0.90 0 -- -- 2 20 80 0.90 0 -- -- 3 20 80 0.90 0 -- -- 4 10 80 0.60 10 50 50 5 10 80 0.60 10 50 50 6 10 80 0.60 10 50 50 7 10 70 0.30 20 100 0 8 10 70 0.30 20 100 0 9 10 70 0.30 20 100 010 35 45 0.50 20 0 10011 35 45 0.50 20 0 10012 35 45 0.50 20 0 10013 45 45 0.50 10 50 5014 45 45 0.50 10 50 5015 45 45 0.50 10 50 5016 45 55 0.90 0 -- --17 45 55 0.90 0 -- --18 45 55 0.90 0 -- --19 20 75 0.60 5 70 3020 20 75 0.60 5 70 3021 20 75 0.60 5 70 3022 20 75 0.60 5 70 3023 15 70 0.60 15 30 7024 15 70 0.60 15 30 7025 15 70 0.60 15 30 7026 15 70 0.60 15 30 7027 30 65 0.40 5 50 5028 30 65 0.40 5 50 5029 30 65 0.40 5 50 5030 30 65 0.40 5 50 50______________________________________
TABLE 10______________________________________Sam- Li.sub.2 O (Si.sub.x Ti.sub.1-x)O.sub.2 x M Al.sub.2 O.sub.3 ZrO.sub.2ple (mol (mol (mol (mol (mol (molNo. %) %) %) %) %) %)______________________________________31 25 50 0.40 15 50 5032 25 50 0.40 15 50 5033 25 50 0.40 15 50 5034 25 50 0.40 15 50 5035 40 50 1.00 5 100 036 40 50 1.00 5 100 037 40 85 1.00 5 100 038 40 75 1.00 5 100 039 35 55 0.30 15 0 10040 35 40 0.30 15 0 10041 35 45 0.30 15 0 100 42* 35 75 0.20 15 0 100 43* 10 75 0.90 5 50 50 44* 5 65 0.90 20 50 50 45* 20 65 0.90 25 50 50 46* 45 40 0.90 15 50 50 47* 50 45 0.90 5 50 5048 25 75 0.90 0 -- -- 49* 25 75 1.00 0 -- --50 35 65 0.90 0 -- -- 51* 35 65 1.00 0 -- --______________________________________
The oxide glass prepared in such a way contains at least one component among Li 2 O, (Si x Ti 1-x )O 2 (wherein 0.30≦X≦1), and M (wherein M represents Al 2 O 3 and/or ZrO 2 ) as shown in a ternary diagram of FIG. 1. In FIG. 1, the shaded hexagonal portion represents the range of the present invention, wherein Points A (20, 80, 0), B(10, 80, 10), C(10, 70, 20), D(35, 45, 20), E(45, 45, 10), and F(45, 55, 0) represents vertices of the hexagon.
A Ni conductive paste was screen-printed on a single side of the resulting ceramic green sheet to form an internal electrode. After drying, a plurality of ceramic green sheets were laminated and pressed in the vertical direction of the sheets to obtain a laminated product. Green ceramic units were prepared by cutting the laminated product into small pieces. After each green ceramic unit was held at 320° C. for 5 hours to remove the binder in the green ceramic unit, the unit was fired at the temperature shown in Tables 11 and 12 for 2 hours in a reducing H 2 /N 2 mixed gas stream having a volume ratio of 3/100 in order to obtain a sintered dielectric element having a thickness of 8 mm.
TABLE 11__________________________________________________________________________ Firing Dielectric Dielectric Capacitance Units UnitsSample Temp. Constant Loss Change CR Product damaged at damagedNo. (°C.) (e.sub.25) tan δ (%) -55° C. +125° C. Cmax (Ω · F) High Temp. by moisture__________________________________________________________________________ 1 1,280 3,290 1.7 -2.8 -8.1 9.0 7,180 0/36 0/36 2 1,280 3,240 1.7 -3.4 -6.9 8.6 7,210 3/36 1/36 3* 1,300 3,560 1.8 -8.8 +19.6 25.1 7,400 6/36 8/36 4* 1,280 2,880 1.8 -4.0 -8.5 9.7 2,270 23/36 16/36 5 1,280 3,160 1.6 -3.8 -7.9 9.3 7,130 2/36 1/36 6 1,280 3,210 1.7 -3.1 -7.4 8.5 7,870 0/36 1/36 7 1,280 3,310 2.0 -3.4 -7.9 9.1 7,490 1/36 0/36 8 1,280 3,390 2.2 -3.7 -8.1 9.5 7,250 2/36 1/36 9* 1,280 3,420 3.9 -3.8 -8.4 9.5 2,900 100 hrs 130 hrs10 1,300 3,280 1.8 -4.4 -6.9 7.7 7,310 3/36 2/3611 1,300 3,120 2.2 -4.7 -6.5 7.2 7,100 2/36 6/36 12* Not measurable due to unsatisfactory sintering even at 1,360° C.13 1,280 3,280 1.8 -5.1 -6.4 7.8 7,810 0/36 0/3614 1,280 3,190 1.6 -5.5 -5.4 6.9 7,490 3/36 1/36 15* 1,260 3,020 2.6 -5.9 -4.8 5.9 2,940 240 hrs 130 hrs16 1,280 3,320 1.9 -4.4 -7.9 9.1 7,280 6/36 4/36 17* 1,280 3,390 4.8 -4.1 -9.2 10.3 2,180 110 hrs 90 hrs 18* 1,280 3,140 3.1 -4.3 -7.4 8.6 4,200 290 hrs 180 hrs19 1,280 3,230 1.7 -4.1 -7.6 8.9 7,140 3/36 1/3620 1,280 3,360 1.8 -4.1 -8.1 9.0 7,280 5/36 3/36 21* 1,280 3,420 2.1 -4.3 -8.6 9.6 3,600 370 hrs 160 hrs 22* 1,320 2,690 2.9 -3.1 -5.4 6.5 5,180 260 hrs 90 hrs23 1,280 3,350 1.7 -3.5 -7.8 8.9 7,600 3/36 3/36 24* 1,260 3,410 1.8 -16.8 -15.1 19.6 4,400 25/36 19/36 25* 1,260 3,330 1.7 -13.1 -10.5 13.7 5,230 11/36 7/3626 1,260 3,210 1.8 -5.4 -7.2 8.3 7,290 0/36 1/3627 1,260 3,190 1.7 -5.5 -6.9 7.9 7,480 2/36 3/3628 1,280 3,090 1.6 -5.7 -6.6 8.1 7,630 3/36 5/36 29* 1,280 2,810 1.9 -6.3 -5.3 7.2 4,800 220 hrs 8/3630 1,260 3,130 1.6 -4.2 -8.4 9.5 7,710 0/36 0/36__________________________________________________________________________
TABLE 12__________________________________________________________________________ Firing Dielectric Dielectric Capacitance Units UnitsSample Temp. Constant Loss Change CR Product damaged at damagedNo. (°C.) (e.sub.25) tan δ (%) -55° C. +125° C. Cmax (Ω · F) High Temp. by moisture__________________________________________________________________________31* 1,260 2,700 1.5 -4.5 -9.3 10.2 7,160 2/36 0/3632 1,300 3,410 1.8 -4.2 -8.2 9.2 7,530 4/36 6/3633* 1,340 3,010 2.5 -4.6 -6.9 7.8 5,200 12/36 18/3634 1,280 3,380 1.8 -3.3 -9.7 10.5 8,100 3/36 3/3635 1,280 3,320 1.8 -2.8 -10.8 11.6 8,620 0/36 4/3636* 1,280 3,280 1.7 +0.6 -15.8 15.8 9,650 2/36 3/3637 1,280 3,410 1.8 -3.8 -7.7 8.6 7,820 2/36 1/3638 1,280 3,360 1.7 -4.0 -7.4 8.4 7,320 3/36 2/3639* 1,280 3,430 1.9 -4.2 -7.3 8.1 6,040 1/36 2/3640* 1,280 2,760 1.6 -2.7 -7.7 8.9 5,810 3/36 0/3641* 1,280 2,590 1.4 -3.1 -7.4 8.5 4,960 4/36 2/3642* Not measurable due to unsatisfactory sintering even at 1,360° C.43* Not measurable due to unsatisfactory sintering even at 1,360° C.44* Not measurable due to unsatisfactory sintering even at 1,360° C.45* Not measurable due to unsatisfactory sintering even at 1,360° C.46* Not measurable due to unsatisfactory sintering even at 1,360° C.47* Not measurable due to unsatisfactory sintering even at 1,360° C.48 1,280 3,280 1.7 -4.2 -7.4 8.6 7,420 2/36 3/3649* 1,280 3,310 1.8 -4.2 -7.0 8.4 7,180 6/36 270 hrs50 1,300 3,340 1.7 -4.2 -6.7 7.9 7,540 2/36 3/3651* 1,300 3,370 1.8 -4.2 -6.4 7.7 7,460 4/36 230 hrs__________________________________________________________________________
A laminated ceramic capacitor was made by coating a silver paste on the both end faces of the resulting sintered material and firing in air to form silver external electrodes. The laminated ceramic capacitor was evaluated by the following items: dielectric constant at a room temperature ε 25 , dielectric loss tan δ, insulation resistance (logIR), temperature-capacitance change (TCC), and resistance against high temperature and moisture. The results are summarized in Tables 11 and 12. In each sample, 36 laminated ceramic capacitors were evaluated.
The dielectric constant ε 25 , and dielectric loss tan δ was measured at 25° C., frequency of 1 KHz, and alternating voltage of 1 V. The insulation resistance was expressed as the product (CR) of the electrostatic capacitance multiplied by the result which was obtained by applying dc voltage of 16 V for 2 minutes at 25° C. The temperature-capacitance change (TCC) was evaluated with the percentage of change of each capacitance at -55° C. and 125° C. to the standard electrostatic capacitance at 25° C., i.e. |ΔC -55 /C 25 and ΔC 125 /C 25 , and the maximum change |ΔC/C 25 | max which is absolute value of the maximum temperature-capacitance change between -55° C. and 125° C.
The resistance against a high temperature was defined as the number of failed samples after applying 64 V of dc voltage to 36 samples at 175° C. for 500 hours, and when all of the samples damaged within 500 hours, its MTTF was shown in Tables 11 and 12. The resistance against moisture was evaluated by the number of damaged samples after applying 16 V of dc voltage to 36 samples at a temperature of 121 ° C. and humidity of 100% for 250 hours. When all of the samples damaged within 250 hours, its MTTF was also shown in Tables 11 and 12.
Tables 11 and 12 show the noticeable effects of the thin layer laminated ceramic capacitor using the non-reduced dielectric ceramic composition in accordance with the present invention, which are in no way inferior to conventional products using palladium and the like as the internal electrode.
In Examples, a sample number with asterisk (*) has a composition deferring from the specified composition in the present invention, and is out of the range of the present invention.
Then, samples with asterisk (*) will be explained.
In sample No. 4, since the BaTiO 3 content is 90.0 mole percent, the rare earth metal oxides and Co 2 O 3 contents are increased resulting in decreased insulation resistance and dielectric constant.
In sample No. 3, since the BaTiO 3 is an excessive 99.6 mole percent, there is no effect of the addition of rare earth metal oxides and Co 2 O 3 , and particularly, the capacitance change is significantly large in the temperature range near the Curie point.
In sample No. 9 containing 0.03 mole percent of the BaO, product characteristics become unstable in the firing atmosphere, resulting in the increased tan δ and decreased insulation resistance.
Sample No. 12 containing 5.0 mole percent of BaO exhibits a decrease in completeness of sintering.
Sample No. 17 containing 0.03 mole percent of MnO exhibits a decrease in the insulation resistance.
Sample 15 containing 2.5 mole percent of MnO exhibits a shortened MTTF due to the slight decrease in the insulation resistance.
In sample Nos. 24 and 25 containing 0.2 mole percent and 0.4 mole percent of MgO, respectively, such low MgO contents do not effectively flatten the temperature-capacitance change curve, and in particular, tend to exhibit a large change in capacitance at a lower temperature region. Further, the insulation resistance does not noticeably increase.
In sample No. 29 containing 6.0 mole percent of MgO, the dielectric constant and insulation resistance are decreased.
In sample No. 18 containing only 0.2 mole percent of NiO, since non-reduced properties of the texture is almost not improved, the insulation resistance is decreased and the MTTF is shortened.
In sample No. 21 containing 3.5 mole percent of NiO, the insulation resistance decreases.
In sample No. 22 containing 3.5 mole percent of Al 2 O 3 , the dielectric constant decreases with the increased dielectric loss due to the decrease in completeness of sintering.
In sample Nos. 40 and 41 in which the alkaline metal oxide content as impurities in BaTiO 3 are 0.05 and 0.07 weight percent, respectively, the dielectric constant decreases.
In sample No. 39 in which 0.1 mole percent of BaZrO 3 is added, the insulation resistance does not so satisfactory increase.
In sample No. 36 in which 5.0 mole percent of BaZrO 2 is added, although the insulation resistance further increases, the capacitance is significantly changed at a higher temperature region.
In sample No. 33, the oxide glass content of 0.3 weight percent causes the decrease in completeness of sintering and very little improvement in the non-reduced property.
In sample No. 31, the oxide glass content of 3.0 weight percent causes the decrease in the dielectric constant.
In sample Nos. 43 through 47, since these compositions are out of the range expressed by the hexagon formed by the six points A, B, C, D, E, and F in the ternary diagram shown in FIG. 1, most of the samples lost transparency without changing into a glass after quenching in iced water, and caused a decrease of completeness of sintering.
Although sample Nos. 49 and 51 are included in the range expressed by the above-mentioned hexagon, these compositions are on line F-A and at the same time X=1.00. These samples show significantly bad characteristics at high temperature or high humidity.
In sample No. 42, since X equals to 0.20, most of the sample lost its transparency without changing into a glass. Thus, the sintering characteristics decreased in this sample.
The present invention is not limited to such a Example, and it is to be understood that modifications will be apparent to those skilled in the art without departing from the scope of the invention. For example, various sub-components can be added into the composition of the present invention without losing the above-mentioned characteristics.
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This invention is directed to provide a non-reduced dielectric ceramic composition, which comprises a main component comprising BaTiO 3 , at least one rare earth metal oxide (Re 2 O 3 ) selected from the group consisting of Tb 2 O 3 , Dy 2 O 3 , Ho 2 O 3 , and Er 2 O 3 , and Co 2 O 3 , where such constituents are contained at a predetermined formulation in the main component, an sub-component comprising BaO, MnO, MgO, and at least one compound selected from the group of NiO and Al 2 O 3 , and an oxide glass mainly containing Li 2 O--(Si x Ti 1-x )O 2 --M wherein M represents at least one member selected from the group consisting of Al 2 O 3 and ZrO 2 , wherein the main component, the sub-component, and the oxide glass are contained in described amounts. The composition is used as dielectric materials, such as monolithic ceramic capacitors, using base metals such as nickel as an internal electrode material.
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GOVERNMENT INTEREST
The invention described herein may be manufactured, used and licensed by or for the U.S. Government for governmental purposes without payment to me of any royalty thereon.
BACKGROUND AND SUMMARY
Modern military vehicles carry an increasing number of electronic components designed, inter alia, to find possible targets, detect and counter enemy attempts to locate and identify the vehicle, and to manage performance of the vehicle. Such vehicles typically carry a number of instruments whose control panels contain manually adjustable dials or knobs rotatable upon shafts threaded to openings in the panel, and it is often critical that these dials or knobs are prevented from wandering even slightly from their settings. The vehicles and their components are subjected to severe vibrations and consequently a spring is commonly compressed between a collar on the threaded shaft and the face of the panel. The spring axially forces together the complimentary threads of the shaft and panel, thereby inhibiting the turning of the knobs or dials by the vibrations. In many cases, however, the nature and intensity of the vibrations is such that a spring alone may not suffice to prevent dial movement, particularly when a vehicle vibration sets up a harmonic vibration in the spring. Unwanted dial movement may also occur, if the spring/dial assembly is vibrated in two directions at once, so that one vibration bends the spring along its central axis as another vibration moves shaft threads relative to panel opening threads within a typical interthread clearance.
My invention is an arrangement wherein the dial is prevented from rotating even under the severe vibrational conditions described above. The invention is a pair of interdigitated sleeves rotatable on the axis of the dial shaft. The sleeves encage a coil spring which inhibits rotation of the shaft in a known manner relative to a substrate or body into which the shaft is threaded. My invention can not only be used on electronic instruments as described above, but can also be used on set screw arrangements and screw type metering valves for precise control of a fluid under intense vibrational conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of my invention as applied to a control knob or dial fixed to a partially threaded shaft, the shaft not being sectioned in the figure.
FIG. 2 is an exploded view of FIG. 1.
FIG. 3 shows a modified tooth design for sleeves that form part of my invention.
FIG. 4 shows an alternate embodiment of my invention.
DETAILED DESCRIPTION
In FIGS. 1 and 2 there is shown a generally cylindrical hollow control knob 10 disposed on the external wall 12 of an electrical panel. Shown unsectioned in the Figures is a knob shaft 14 coaxially attached to knob 10 and threadingly received in wall 12. Rotatable on shaft 14 about common axis 16 and extending along this axis is a sleeve 18 which rotatingly bears against an inner peripheral surface 20 that is parallel to wall 12. Bearing surface 22 of sleeve 18 may have a TEFLON material or other low friction material used as a coating to minimize the torsional forces that will be transferred between sleeve 18 and knob 10 when knob 10 is manually rotated on axis 16. Sleeve 18 has an axial opening 24 for accommodating shaft 14, the opening preferably being slightly diametrically larger than the shaft so that the shaft turns freely in opening 24, and so that little or no torque is transferred between shaft 14 and sleeve 18. Additionally, the sides of opening 24 can be coated with a low friction material to further insure that essentially no torque is transferred between shaft 14 and sleeve 18. Sleeve 18 has a series of elongate teeth 26 (FIG. 2) extending parallel to axis 16 and extending away from bearing surface 20, the teeth preferably having angular or arcuate widths that are equal to each other and equal to the angular width of circumferential gaps between the teeth.
A second sleeve 28 has a configuration that is preferably the same as sleeve 18, sleeve 28 also being rotatable about common axis 16 on shaft 14. Sleeve 28 has an axially oriented bearing surface 30 (FIG. 2) which slidingly rotates upon a flat bearing surface 32, bearing surface 32 preferably having a low friction coating so that sleeve 28 will rotate freely on mounting surface 32. Opening 34 in sleeve 28 is slightly larger in diameter than shaft 14 and the sides of opening 34 is also preferably coated with a low friction material so that shaft 14 and collar 28 can rotate independently of one another about common axis 16 without a transfer of torque therebetween. Teeth 36 (FIG. 2) of sleeve 28 are equal in arcuate width to one another, to the circumferential gaps alternated with teeth 36 and to the angular width of teeth 26 on sleeve 18 so that teeth of the respective sleeves will fit in close interdigitated relation when the sleeves move together.
When sleeves 18 and 28 are moved together and their respective teeth are interdigitaled, the sleeves form a cage-like or capsule-like enclosure which contains and protects compression coil spring 38. Spring 38 and the sleeves are of the same metal or are of metals which are close together in the electromotive series so that there is no appreciable corrosion of the spring and therefore no reduction of its spring rate over long periods of time. Spring 38 will be under a selected range of axial compressive loads in the typical arrangement shown in FIG. 1, and the inner diameter of the sleeves will be sized so that the spring will not bind against the inner peripheral walls of the sleeves when the spring is within the selected range of axial loading. The inner diameter of the sleeve is preferably equal to the particular diameter to which the spring expands when the largest acceptable compressive load is on the spring. It is preferred that inner diameter of the sleeves be no greater than the aforementioned particular spring diameter so that the spring is given minimum ability to bend relative to its own axis.
The range of axial compressive loads on spring 38 will vary from design to design, but the minimum value for the range will be the axial force needed to reliably keep knob 10 in a selected rotational position on the face of a control panel. The maximum compressive force will be the greatest force with which the spring can be loaded without damaging threads on shaft 14 or damaging the complimentary threads in wall 12, or making it too difficult to turn knob 12 manually. It may be preferred that the two sleeves will completely mesh together just before the maximum value of the compression upon spring 38 would be reached, so that there are no axial gaps in the fit between the two sets of teeth. This latter feature has two advantages. First, the cage or capsule formed by the sleeves will be completely closed, or nearly so, in the preferred, operational compression range of the spring whereby the spring receives some protection from dust, dirt or foreign matter. Second, there will be a sudden increase in torque necessary to turn knob 10 as the maximum preferred compression for spring 38 is approached, so that a human operator turning the knob will have a palpable feedback just before this maximum value is reached, whereby the operator is warned to turn the knob no further.
FIG. 3 shows a detail view of meshed teeth on sleeves 118 and 128 similar to sleeves 18 and 28 in FIGS. 1 and 2, except that teeth 126 and 136 in FIG. 3 are different from teeth 26 and 36 in FIGS. 1 and 2. Teeth 126 and 136 have bevels as at 140 and 142 which guide these teeth into interdigitated engagement when sleeves 118 and 128 are closed together. In addition, one of teeth 126 has a set of equally spaced graduation or scale marks as seen at 144 and one of teeth 136 has an indicator such as arrowhead 146, the relative positions of the arrowhead and graduation marks providing an indication of the axial compression on spring 38 contained by sleeves 118 and 128. Marks 144 may be numbered, labelled or color coded to increase the ease with which the human operator can equate the marks with corresponding sets of values for compression of spring 38.
FIG. 4 shows an alternate embodiment of my invention wherein sleeves 218 and 228 are the same as those shown in FIGS. 1 and 2, and spring 238 is the same as spring 38 in those figures. Shaft 214 is an unthreaded shaft having a retention collar 244 to trap the assembly of sleeve 218, sleeve 228 and spring 238 against the interior of wall 212 of an instrument panel. Dial 210 rotatingly bears against the exterior of wall 212, the axial load of dial 210 toward wall 212 being born up by bearing or bushing 246.
I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described herein since obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the appended claims.
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A mechanism to prevent a dial or knob of an instrument panel from wandering from a manual setting when the panel is subjected to severe vibrations. The mechanism includes a compression spring to place a load on the dial in the direction of the dial's rotational axis. The mechanism also has a pair of roothed, interdigitated sleeves rotatably disposed along the axis to prevent torque transfer between the dial and the spring.
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BACKGROUND
This invention relates to sprag clutches, and particularly to energizers as used in sprag clutches for urging the sprags into mechanical engagement with the inner and outer races thereof.
Sprag clutches are utilized principally in indexing operations, such as impact hammer drills for boring. Under high rates of impact, for example those at or exceeding 3,000 impacts per minute, the energizers of such clutch applications have relatively short useful lives, and must consequently be replaced frequently. Conventional energizers are coiled garter springs made of steel, which in addition to chattering against and wearing the energizing surfaces of the sprags, suffer loss of spring tension during useful life, resulting in a continuing increase in response time.
SUMMARY OF THE INVENTION
The sprag clutch energizer disclosed and claimed herein reduces the chatter against and wear of the energizing surfaces of the sprags in contact therewith. Both lighter and more resilient, the energizer of this invention has an inherently quicker response time which is not subject to continuous deterioration over its useful life from loss of spring tension. Thus, in addition to longer useful life, the energizer of this invention renders better response performance under service conditions requiring high impact rates.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view of a portion of a sprag clutch, including a preferred embodiment of the energizer of this invention.
FIG. 2 is an end elevation of the view in FIG. 1 taken along lines 2--2.
FIG. 3 is a second cross sectional view of a portion of a sprag clutch, including a second preferred embodiment of the engergizer of this invention.
FIG. 4 is an end elevation of the view in FIG. 3 taken along lines 4--4.
FIG. 5 is a third cross sectional view of a portion of a sprag clutch which is similar to that of FIG. 1 (except that the clutch of FIG. 5 is without a cage) which includes the first preferred embodiment of the energizer as shown in FIG. 1.
FIG. 6 is an end elevation of the view in FIG. 5 taken along lines 6--6.
FIG. 7 is a fourth cross sectional view of a portion of a sprag clutch, including the first preferred embodiment of the energizer of this invention.
FIG. 8 is an end elevation of the view in FIG. 7 along lines 8--8.
FIG. 9 is a fifth cross sectional view of a portion of a sprag clutch, including a third preferred embodiment of the energizer of this invention.
FIG. 10 is an end elevation of the view in FIG. 9 along lines 10--10.
DESCRIPTION OF PREFERRED EMBODIMENTS
It will be noted, particularly in FIG. 1, that the energizers 28 are separate and distinct from the sprags 16, having only frictional contact therewith. This is in contrast to some designs which integrally mold energizers with sets of sprags. The cross section of the energizer 28, as apparent, does not occupy the total groove cross section. The energizer 28 thus establishes a band of resilient frictional contact over less than the total inside area of the annular recess. This serves to avoid the application of undesirable bending moments to the energizers, and thus allows greater relative freedom of movement for the sprags 16.
A sprag clutch utilizing the elastomeric energizer of this invention comprises annular inner and outer races 10 and 12, respectively, as shown in FIGS. 1 and 2. The races are coaxial and define therebetween an annular space 14 which contains a plurality of circumferentially spaced sprags 16, one of which is shown. In the embodiment of FIGS. 1 and 2, the clutch contains an annular cage member 18 which is positioned with the sprags in the annular space 14 to retain the sprags therein. The cage member 18 comprises two cage rings 20 joined together by cross bars 22, the latter forming interspaces for receiving arcuate inner race engaging portions 24 of sprags 16.
The sprags 16 each contain grooves 26 in the sides thereof for containment of elastomeric energizers 28, which in the embodiment of FIGS. 1 and 2 are contracting O-rings. Thus energizers 28 are slightly stretched in order to apply a contracting or inward force on the plurality of sprags 16. In the embodiment of FIGS. 1 and 2, the sprags 16 each contain two ears 30 projecting outwardly thereof, from side walls 32, and parallel to the rotational axis of the clutch (vis. perpendicularly to the plane of FIG. 2). As will be noted in FIG. 1, ears 30 comprise the lateral extremities of the above-noted arcuate inner race engaging portions 24 of the sprags 16. The interface of the side wall 32 and ear 30 form the aforesaid groove 26 in each sprag 16. The groove 26 in each of the circumferentially spaced sprags 16 aligns with the groove of each adjacent sprag. Together the grooves form an annular recess in the plurality of sprags which lies in the plane of FIG. 2, and contains the O-ring energizer 28.
Referring now to FIG. 2, it may be appreciated that as the inner race 10, as a driver, would turn clockwise relative to the outer race 12, the inner race engaging portion 24 of sprag 16 will be in contact with inner race 10 by virtue of the contracting energizer 28. Friction between the latter surfaces will force the sprag 16 to cock counterclockwise, thus forcing the outer race engaging portion 34 into contact with the outer race 12, thus tending to lock the two races together in a driving relationship. As, however, the inner race is retarded, the outer race 12 will "overrun" the inner race 10 by turning clockwise relative thereto, the sprag 16 will be forced to cock clockwise thus freeing the two races from driving relationship. In the operation of an impact hammer or similar equipment enduring rapid cycling of the aforementioned positional relationships, it may be appreciated that the energizer will be subjected to severe cyclic forces. The lighter relative weight of elastomer to steel ensures reduction in such forces, thus enhancing energizing response. The resilient nature of the elastomer surface as compared to steel surfaces ensures less wearing of both the energizer and the sprags in contact therewith. In addition, chatter is controlled because of the resilient yielding nature of the energizer.
The elastomeric energizer 28 may be utilized successfully in still other embodiments. Thus FIGS. 3 and 4 show a sprag clutch of the expanding energizer type, wherein an elastomeric energizer 28 may be compressed slightly in order to effectuate a friction drag relationship between the outer race engaging portion 34 of sprag 16 and the outer race 12. In the latter case, the outer race would function as driver, and counterclockwise motion thereof (FIG. 4) would lock the races in the manner heretofore described.
FIGS. 5 and 6 show a sprag energizer 28 of the contracting type as in FIGS. 1 and 2, but shown operating in a cageless sprag clutch, the latter being familiar to those skilled in the art.
FIGS. 7 and 8 show yet another embodiment of a sprag clutch utilizing the present invention. The sprag 16 (FIG. 7) contains a groove 26 defined by a U-shaped slot 36 in its outer race engaging portion 34. In the preferred embodiment of FIG. 7, the slot 36 is centered within the portion 34, however it could just as well be offset, and it could have a shape other than a "U", as for example, a "V". In addition the elastomeric energizer shown in FIG. 7 is of a contracting type. Alternatively, an expanding elastomeric energizer could be used, wherein the slot 36 would be positioned in the inner race engaging portion 24 of the sprag 16.
FIGS. 9 and 10 show an elastomeric energizer 28 having a square cross section rather than a circular cross section as exemplified in the previous figures. Thus, the invention has been shown to be amenable to many configurations; both as to style of the sprag clutch in which the energizer is used, as well as to the cross section of the energizer per se.
The elastomers, as used herein, are preferably of high polymer materials, exhibiting little plastic flow, and quick and nearly complete recovery from an extending force, as for example, Nitrile or Buna N.
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An elastomeric energizer for a sprag clutch provides an improved mechanism for engaging the circumferentially spaced sprags thereof with the inner and outer races of the clutch. The energizer also dampens sprag oscillations, thereby cutting clutch chatter, and avoiding localized stresses on the energizing surfaces of the sprags. In a preferred embodiment, the sprag energizer is an O-ring contained within an annular recess formed by grooves in the sides of the individual sprags.
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This application is a continuation-in-part of Application Ser. No. 101,105, filed Sept. 25, 1987, now abandoned.
BACKGROUND OF THE INVENTION
This invention generally relates to an apparatus used for wrapping a film around food. More particularly, this invention relates to an apparatus for wrapping a mixture of meat and vegetables resulting in the production of a finished product, such as, a "lumpia" (i.e., a Philippine style egg roll), egg roll, or the like.
Often, the making of a lumpia or an egg roll requires a significant amount of patience, especially in the final production step of wrapping the mixture of meat and vegetables. Not only must there be a reasonably cut or sized food wrapping material, an appropriate amount of filling, i.e., the mixture of meat and vegetables to be wrapped, should be provided as well. In the mass production and sale of lumpias or egg rolls, time and accuracy are of the essence in order to satisfy large orders which is typically required since the lumpia or egg roll, due to size and considerably appetizing taste, is a fast consuming food product.
Accordingly, there is a need for a food wrapper apparatus and a method of operating thereof as in the instant invention which can provide the essential rapid and efficient production of a significant number of lumpias or egg rolls. Such a food wrapper apparatus should be operated so as to permit a user to rapidly and easily produce a significant number of lumpias or egg rolls. Moreover, the food wrapper should be made of durable and rigid materials which can be easily and efficiently cleaned on a regular basis in compliance with governmental regulations. Similarly, it is desirable to have the food wrapper easily mounted on a work table and easily transported and stored when not in use. The food wrapper should be rigidly erect from a working table so as be easily and efficiently accessible to a user.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a food wrapper apparatus and a method of operating thereof.
It is another object of this invention to provide a food wrapper apparatus which can be efficiently operated in order to rapidly and efficiently produce a significant number of lumpias or egg rolls.
It is another object of this invention to provide at least one food wrapper apparatus or a plurality thereof which can be easily and efficiently mounted on a working table.
It is still another object of this invention to provide a food wrapper apparatus which can be made easily accessible to a user when in use.
It is yet another object of this invention to provide a food wrapper apparatus which can be easily transported and stored when not in use.
It is a further object of this invention to provide a food wrapper apparatus which is made of durable and rigid materials which can be easily and efficiently cleaned on a regular basis in compliance with governmental regulations.
It is further object of this invention to accomplish the above by a food wrapper apparatus which will be sufficiently rigid when in use, durable in construction, inexpensive and easy to manufacture.
In accordance with one embodiment of this invention, a food wrapper apparatus for producing lumpias or egg rolls is disclosed. In this embodiment, an upper member mounts on a support member which extends above a base. The base is then seated on a work table. The upper member has slots passing therethrough for guiding a film of guiding material, such as a plastic guiding film or the like. The upper member also has a U-shaped upper portion for accommodating therein a roller rod during the enclosing or wrapping of at least one lumpia or egg roll by a food wrapping material. Operably coupled to the base and support member is at least one pair of scissors which can catch a fully wrapped lumpia or egg roll for effectively cutting thereof to a plurality of lumpias or egg rolls at desirable sizes.
The foregoing and other objects, features and advantages of this invention will be apparent from the following, more particular, description of the preferred embodiments of this invention, as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an embodiment of a food wrapper apparatus in accordance with the present invention showing the upper member mounted on a support member extending above a base which seats on an associated work table.
FIG. 2 is a cross-sectional view taken along line 2a--2a of FIG. 1 showing an upper member with a U-shaped upper portion, the support member, base and at least one pair of scissors operably mounted onto the support member and the base.
FIG. 2b is a side elevational view taken along line 2b--2b of FIG. 2a showing the manner in which the support member is coupled to the base.
FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 1 showing the manner in which the upper member is configured at the center portion thereof.
FIG. 4 is top perspective view of a plurality of pairs of scissors.
FIG. 5a is an exploded perspective view of a roller rod; and FIG. 5b is a side elevational view of a fully assembled roller rod ready for use.
FIG. 6a is a front elevational view of a longitudinal clip; and FIG. 6b is a side elevational view of the longitudinal clip.
FIG. 7a is a front perspective view of a meat filling dispenser accommodated within a meat filling container; FIG. 7b is an exploded perspective view of the meat filling dispenser; and FIG. 7c is a perspective view of the meat filling dispenser in a non-dispensing position.
FIG. 8 is a schematic view of the manner in which a film of guiding material is positioned on the upper member through slots of the upper member, and mounted thereto by the longitudinal clips.
FIGS. 9a through 9d are schematic views illustrating a step-by-step operation of the manner in which the food wrapper apparatus of the instant invention is used.
FIG. 10 is a top elevational schematic view of the upper member having a food wrapping material and meat filling thereon ready to be wrapped.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a perspective view of a food wrapper apparatus, generally designated by reference number 1, showing the apparatus ready for use. The food wrapper apparatus 1 has an upper member 3 mounted on a support member 5 which in turn extends over a base 7. The base 7 sits on a portion of a work table 10. The base 7 has legs 12, 14 which allows the base 7 to sit on the work table 10 above a holding pan 16. The work table 10 is preferably large enough to permit or accommodate thereon a plurality of food wrapper apparatuses 1 of the present invention, if desired.
As shown in FIG. 2, the upper member 3 has a generally U-shaped upper portion 18 which partially extends along the upper portion of the upper member 3. The U-shaped portion 18 is used for accommodating therein a roller rod 20 which will later be more fully discussed. A pair of scissors 22, preferably made of stainless steel, is operably mounted onto the support member 5 by an upwardly extending member 24 having a lip member 26 where the scissor 22 sits when in use. Another upwardly extending member 28, preferably L-shaped, is attached to the base 7 for integrally mounting thereon another portion of the scissor 22 as shown. The scissor 22 has an upwardly extending member 30, integral or attached thereto, which is accessible for a user when the need to manipulate or operate the scissor 22 arises. The upwardly extending member 30 is resiliently coupled to a portion of the scissor 22 by a spring 32, as shown in FIG. 2.
FIG. 2b more closely illustrates the manner in which the support member 5 is coupled by bolts 32 to the base 7.
FIG. 3 shows the manner in which the upper member 3 is configured at the upper center portion 35 having elongated slot 37 abutting thereto. As further seen in FIG. 3, the U-shaped portion 18 of the upper member 3 does not extend through the center portion 35. Passing through the upper member 3 are upper, middle and lower slots 40, 42, 44, respectively. Below the middle slot 42, as shown in FIG. 3, is an elongated bar 46 which is attached to opposing sides 48 of the upper member 3. The lower slot 44 is preferably located immediately above the plurality of scissors 22. The functions of the upper center portion 35 and slots 37, 40, 42, 44 will be apparent when describing the operation of the instant invention.
FIG. 4 illustrates the manner in which a plurality of scissors 22 can be provided in series with the various portions previously discussed for FIG. 2a. The upwardly extending member 24 preferably has at least one aperture 50 passing therethrough for accommodating therein a bolt 52 (see, FIG. 2a) for fastening the upwardly extending member 24 to the support member 5.
FIG. 5a illustrates a roller rod, generally referred to by reference numeral 55, having a middle rod 57 with end tubes 59. The ends of the end tubes 59 preferably have integral protruding members 60 abutting slots 62. Each of the ends of the middle rod 57 has a knob-like member 64 for catching the integral protruding member 60 when the roller rod 55 is fully assembled as shown in FIG. 5b.
FIG. 6a illustrate an elongated clip 66 having a U-shaped configuration as shown in FIG. 6b. The clip 66 removably attaches a film of guiding material 80 to the upper center portion 35 and the elongated bar 46, as described more fully below.
FIG. 7a shows a meat filling dispenser 68 accommodated within a meat filling container 70 which holds the meat filling to be wrapped. Further illustrated in FIG. 7b is the meat filling dispenser 68 shown in its dispensing position having a block member 72, preferably made of plastic material which can be easily cleaned and in compliance with sanitary regulations. The dispenser 68 further has a handle 74 and a preferably U-shaped enclosing member 76 coupled thereto for accommodating therein the block member 72 and meat filling (not shown). The dispenser 68 has an elongated member 78 passing through the handle 74 for sliding therethrough. A spring 80 around the member 78 is pinned at one end with a pin 82. The pin 82 has a side passing through an aperture (not shown) passing through the elongated member 78. A cap 84 may be removable from the elongated member 78. FIG. 7c shows the meat filling dispenser 68 in a non-dispensing position. When the block member 72 is fully drawn into the enclosing member 76, an elongated space 86 within the enclosing member 76 is provided for accommodating the meat filling (not shown) from the container 70.
When the dispenser 68 is used, the block member 72 is initially drawn into the enclosing member 76 and the dispenser 68 is preferably pushed in a side-to-side motion onto the meat filling in the container 70 for an even accumulation of meat filling into the enclosing member 76. The meat filling is dispensed from the enclosing member 76 by pushing the cap 84 towards the handle 74 for allowing the block member 72 to push out the meat filling out of the enclosing member 76 onto the food wrapping material 88 in a manner which will is further discussed below.
The manner in which the food wrapper apparatus 1 operates is hereinafter described. Referring first to the schematic view of FIG. 8, the guiding film of material 80, such as plastic film, cellophane, or the like is initially guided through in the manner shown in FIG. 8.
One end of the guiding film 80 is attached to the elongated bar 46 by the elongated clip 66 as shown. The guiding film 80 then traverses through the lower elongated slot 44 from below the upper member 3 and into the upper elongated slot 40 from above the upper member 3. The guiding film 80 is then passed through the elongated slot 37 and then attached to the center portion 35 of the upper member 3.
The tension of the guiding film 80 is initially calibrated or positioned in the manner hereinafter described for FIGS. 9a to 9b. The elongated clip 66 is initially taken out from the center portion 35 in order to allow ease of tension for the guiding film 80 for initial calibration or positioning. The roller rod 55 is placed beneath the guiding film 80 while a typical rod, either shallow or solid, is placed over the guiding film 80 through the middle elongated slot 42 and rested on the elongated bar 46, shown in FIG. 9a.
As illustrated in FIG. 9b, the roller rod 55 is pulled up over the rod 88 towards the arrow, as shown, taking along with it a portion of the guiding film 80. The roller rod 55 (shown in dashed lines) is placed in a position just below the lower elongated slot 44. The end of the guiding film 80 is thereafter attached to the center portion 35 of the upper member 3 with an elongated clip 66.
After the guiding film 80 has been properly positioned or calibrated in the manner discussed above, the apparatus of the instant invention is ready for wrapping meat filling 90.
As illustrated in the schematic view in FIG. 9c, the roller rod 55 is positioned on the center portion 35 of the upper member 3. Food wrapping material 88, typically made of flour and easily accessible in food markets, is then placed on the portion of the guiding film 80 above the middle elongated slot 42. The dispenser 68 having meat filling in the enclosing member 76 is then placed on the wrapping material 88.
FIG. 10 shows as top elevational schematic view of the arrangement shown in FIG. 9c. The wrapping material 88 is preferably cut in a half-circle shape, as shown in FIG. 10, while the meat filling 90 in an elongated form is placed thereon.
As further illustrated in FIG. 9d, the roller rod 55 is pulled up over the meat filling 90 and rolled in the direction shown in the arrow. While the roller rod 55 is rolled in the direction of the arrow, the guiding film 80 portion beneath the wrapping material 88 is rolled around the meat filling 90. While the roller rod 55 is further rolled down toward the direction of the arrow on the upper member 3, the rolled meat filling 90 with the wrapping material 88 thereon is further rolled down the upper member 3 until the fully wrapped food product (i.e., the lumpia or egg roll) 95 reaches and passes through the lower elongated slot 44. After passing through the lower elongated slot 44, the fully wrapped food product 95 then lands on the plurality of scissors 22. More particularly, the fully wrapped food product 95 lands on the portion of the scissor which is removably attached to the lip member 26 of the upwardly extending member 24 previously discussed. The upwardly extending member 30 of the scissors 22 is then pushed downward in order to cut the fully wrapped food product 95 into multiple lumpias or egg rolls. The resulting multiple lumpias or egg rolls then drop to the pan 16. If desired, food mixture, such as egg material or the like, can be brushed onto the free edge of the lumpia or egg roll for proper sealing. The lumpias or egg rolls are then packed, placed in a deep-freeze container and stored in a freezer thereafter for later consumption.
While the invention has been particularly shown and described in reference to preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the spirit and scope of the invention.
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A food wrapper apparatus is disclosed having a base mounted onto a work table, a support member mounted onto said base, an upper member mounted onto said support member, a roller road cooperating with a guiding film on said upper member for enclosing food with a food wrapper, and at least one cutter for cutting the fully enclosed food into multiple pieces which are accommodated in a pan beneath the base. The food being wrapper results in the rapid and efficient production of a delicacy, such as lumpia, egg roll, or the like.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a human tissue culturing system and to an instrument (CO 2 incubator) for culturing tissue(s) keeping the system. The present invention relates to a simple means for preventing the possible contamination of individual(s) and excluding the mixup when human tissue(s) or cell(s) is/are cultured.
[0003] 2. Description of the Related Art
[0004] Tissues and cells derived from a mammal such as human are routinely cultured using a CO 2 incubator. Cells such as myocardial cells, dendritic cells, hematopoietic stem cells and neural stem cells derived from human are cultured as the autograft of human cell(s)/tissue(s) is realized. Each cell is proliferated in a CO 2 incubator, and is processed for use in a clean bench. This culture is very strictly controlled. It is sometimes required that cells derived from one patient are treated in one room or that the treatment are carried out by two workers in order to prevent the contamination between cells during culturing and processing. Carrying out these regulations in a practical hospital, however, requires the construction of a large-scale facility, makes the business very complex, and makes it very difficult to culture self-cells to transplant.
SUMMARY OF THE INVENTION
[0005] The present invention was conceived in view of the above situations. It is therefore the object of the present invention to provide a system and an apparatus that minimize the possibility of the mis-work in order to simply and safely achieve the culturing of cells for autografting a human tissue or the like.
[0006] To achieve the above object, the present invention provides:
[0007] 1. A human cell/tissue culturing system including a plurality of incubators, each incubator capable of aseptically storing/culturing cell(s) or tissue(s) derived from a (human) individual and identifying the cell(s) or the tissue(s) during incubation, wherein each incubator comprises a detector corresponding to an individual key, the response of the detector permitting opening/closing of a door of each incubator, the response of the detector of one incubator triggering the interception of the function of the detector(s) of other incubator(s) to consequently inhibit opening/closing of the door(s) of the other incubator(s).
[0008] 2. The human cell/tissue culturing system according to claim 1 , wherein the detector corresponding to the key of the incubator carries such a regulation function as to allow the function of the detector of other incubator to be interrupted even when the key is drawn out.
[0009] 3. The human cell/tissue culturing system according to claim 1 or 2 , wherein the key is capable of responding to a detector of a clean bench that permits controlling of the initiation of the use in the clean bench during the treatment in the clean bench in which cell(s) or tissue(s) derived from human(s) is/are taken out from an incubator.
[0010] 4. The human cell/tissue culturing system according to any one of the preceding claims, wherein the key is an electric key, and wherein the detector for detecting the key is an electric detector.
[0011] 5. An instrument for culturing tissue(s), the instrument keeping the function of the human cell/tissue culturing system according to any one of the preceding claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] [0012]FIG. 1 illustrates a set of incubators;
[0013] [0013]FIG. 2 is a wiring diagram;
[0014] [0014]FIG. 3 is a wiring diagram; and
[0015] [0015]FIG. 4 is a sequence circuit diagram.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Culturing human cell(s)/tissue(s) is a method for isolating a tissue, an organ, a lymphocyte, a fertilized egg or a dendritic cell derived from human or a fused cell prepared from a dendritic cell and a tumor cell, followed by proliferating cell(s) in a culture vessel such as flask and petri dish, wherein the vessel usually contain cell(s) derived from human, a medium, a human or fetal calf serum, and so on. The incubation is usually carried out at a temperature of 37° C. at a CO 2 concentration of 5% (or 3% if desired) and a saturated humidity. The CO 2 incubator is an instrument that was developed to maintain an environment suitable for culturing cell(s) or tissue(s). For example, the temperature is a condition that is physiologically necessary for proliferation of cell(s). A concentration of CO 2 is set to stably maintain the pH of a medium necessary for the proliferation of cell(s). Sodium hydrogen carbonate (NaHCO 3 ) added to regulate a concentration of proton in culture medium is dissociated as follows: 2NaHCO 3 ⇄Na 2 CO 3 +H 2 O+CO 2 . Emission of CO 2 results in the increase in Na 2 CO 3 , and pH becomes 7.4 or higher, and the high pH causes a trouble in culturing a cell. To prevent the trouble, CO 2 gas is supplied into the CO 2 incubator to reconvert Na 2 CO 3 to NaHCO 3 , and pH of the medium can be equilibrated between 7.1 and 7.4.
[0017] A lid of flask or the like for culturing human cell(s) or tissue(s) must be loosened to supply CO 2 gas in the incubator into the culture flask and exchange the air. If water evaporates from the medium in the culture flask during incubation, the salinity of the medium is changed to remarkably affect the conditions for culturing the cell(s). It is necessary to humidify inside the CO 2 incubator in order to prevent the drying. The humidification is usually carried out by making the atmosphere of the incubator in a saturation state by spontaneously evaporating water in a vat in the CO 2 incubator. Moreover, it is also necessary to circulate air to the CO 2 incubator.
[0018] In the present invention, the CO 2 incubator as described above is recognized as one incubator for culturing cell(s) derived from one individual. The law requires that cell(s) derived from one individual are cultures in one incubator. Therefore, incubators are usually arranged vertically and horizontally like cube-type lockers (FIG. 1). Each incubator has a function of regulating environmental culture conditions such as gas composition by supplying the above gas. The control function can be carried out by a central management system or individually.
[0019] Cell(s) or tissue(s) derived from human (s) is/are aseptically stored/cultured in each incubator, and the cell(s) or tissue(s) can be individually identified in association with a computor or simply by a manual operation during incubation. The present invention is a cell-culturing system in which incubators are controlled, wherein each incubator has a detector corresponding to characteristic and individual key by which identification is carried out with a computor or manually. When specific cell(s) is/are processed, it becomes necessary to open/close, with a key, an incubator in which the specific cell(s) is/are stored/cultured, wherein the key corresponds to each incubator in which a detector that can respond to each key is installed. Response of the detector permits opening/closing a door of each incubator.
[0020] In case a door is unlocked with response to the detector of one incubator, functions of all other detectors that are controlled are blocked as a result of synchronization, so that other doors are locked.
[0021] A detector corresponding to a specific key of a specific incubator can carry such a regulation function that a function of the detector of other incubator can be blocked by drawing out the key. Such a function permits detecting a key with a detector installed in a clean bench to permit using the clean bench under control in case a specific key is drawn from a specific incubator to keep the identification of a clean bench when cells are taken out of an incubator to aseptically process them in a clean bench or the like. Therefore, it is a preferred embodiment as a system of the present invention to install a detector that permits identifying a key also for a clean bench.
[0022] Although an electric key, a magnetic key and an optical key are preferably used for a key according to the present invention, other keys can also be used. An electric key is most suitable considering that it is not preferable that current flows in an instrument used for culturing human cells, and that an electric key is simple and reliable. An electric detector, a magnetic detector, an optical detector or the like is installed corresponding to the type of the key.
[0023] A method for generally controlling incubators with a key system according to the present invention is installed in an instrument as a system to provide an instrument for culturing tissue(s) having a function as a useful and reliable system for culturing human cell(s)/tissue(s).
EXAMPLES
[0024] The present invention will now be described in more detail by way of examples. These examples are however to be regarded as a help in concrete recognition, and the scope of the present invention is not intended to be limited by the examples which follow.
Example 1
[0025] Set of Incubators
[0026] [0026]FIG. 1 illustrates the front view of a practical state in which incubators according to the present invention are collectively managed. A monitor for identifying an individual and monitoring culture conditions is installed on the upper part of each incubator. A detector, which is a key box, is installed in the lower right part of each incubator.
Example 2
[0027] [0027]FIGS. 2 and 3 illustrate charts of interlock-control circuit. When one key is turned right to be ON, a corresponding solenoid unlocks a rod from a hole of an outer door to permit opening/closing the door of the corresponding incubator. Such a regulation circuit that makes operation of key switches of five other incubators ineffective at that time is written in a sequencer. Therefore, it becomes impossible to open/close the outer doors of five other incubators. FIG. 4 illustrates a sequencer control circuit. When input relay X000 is input (key switch 1 is ON), for example, the regulation relay becomes ON. In addition, when regulation relays M 2 -M 6 are all OFF (key switches 2 - 6 are OFF), M 1 becomes ON. When each key switch becomes ON, each corresponding control relays M 1 -M 6 become ON. Only when all the control relays M 2 -M 6 are OFF, when key switch 1 becomes ON, control relay 1 becomes ON. For each output relays (Y000-Y005), when M 1 is ON, Y000 becomes ON to open the outer door. When each of regulation relays M 2 -M 6 becomes ON, an outer door of each corresponding incubator is unlocked.
[0028] Symbols and codes in figures are described below:
[0029] {circle over (1)}-{circle over (6)} mean incubators.
[0030] X 0 -X 7 mean sequencer input symbols. For example, X 0 controls the key switch of CO 2 incubator 1 . When key X 0 is pushed, the key switch of CO 2 incubator 1 becomes ON. The same applies to the other keys. X 6 and X 7 are spares. ‘1’ is sometimes expressed as ‘001’ in Figures using a three-digit system. Others are also sometimes expressed in a similar manner.
[0031] Y 0 -Y 7 mean sequencer output signals. For example, Y 0 is a lock solenoid for CO 2 incubator 1 , and is output to S 1 . CO 2 incubator 1 is locked by this.
[0032] COM means a sequencer input signal and is an input-side common terminal.
[0033] COM 0 -COM 3 mean sequencer output signals and are output-side common terminals 0 - 3 .
[0034] ZRST has a function of resetting all of relays Y 0 -Y 5 , and is reset for safety when the power supply is ON.
[0035] M8002 means a special relay that momentarily becomes ON when a sequencer is energized.
[0036] M8000 means a special relay that becomes ON when a sequencer is energized.
[0037] Symbol 1
[0038] means an ON(a) junction that becomes ON when each relay (each of X, Y and M can be assigned) is energized.
[0039] Symbol 2
[0040] means an OFF(b) junction that becomes OFF when each relay (each of X, Y and M can be assigned) is energized.
[0041] ‘+24’ means a plus terminal of a DC 24V service power supply.
[0042] ‘L’ means a sequencer power supply connection terminal.
[0043] ‘N’ means a sequencer power supply connection terminal.
[0044] (It works at an arbitrary voltage between AC 100V and 240V between terminals L and N.)
[0045] ‘Sequencer’ is a computor only for a control circuit. Writing in by a predetermined method (symbol) permits controlling the circuit.
[0046] ‘SQ’ means sequencer.
[0047] ‘FXOS-14MR’ is a sequencer made by Mitsubishi Electric Corp.
[0048] ‘DC.24V’ means DC 24 V.
[0049] ‘+24V’ means a plus side of DC 24 V.
[0050] ‘S 1 ’-‘S 6 ’ mean solenoids 1 - 6 , wherein ‘solenoid’ means an electric part so designed as a rod moves by an electromagnetic power made by a magnetic coil against a power of a spring. This output relay unlocks each CO 2 incubator.
[0051] ‘LE30-13’ is a solenoid made by Dakigen Corp.
[0052] ‘KS 1 ’-‘KS 6 ’ mean key switches 1 - 6 that become ON/OFF with keys.
[0053] ‘S-187-90-E-1’ is a key switch made by Dakigen Corp.
[0054] ‘P 1 ’-‘P 6 ’ mean signal lights 1 - 6 that light when solenoids are energized.
[0055] ‘S(W)’ means one phase of an AC power supply, wherein ‘W’ means white covered wire.
[0056] ‘R(R)’ means another phase of an AC power supply, wherein ‘R’ means red covered wire.
[0057] ‘E’ means earth.
[0058] ‘MC 1 - 6 ’ mean metal plug sockets 1 - 6 , wherein ‘metal plug socket’ means a metallic, electric part that is used for connect a flexible cord and can be fixed usually with a metallic screw cap.
[0059] ‘NCS-1604RP’ is a metal plug socket made by Nanahoshi Science Laboratory.
[0060] The present invention can provide a practical means that permits very efficiently, very simply and individually managing/culturing human cell(s), and is extremely useful for practically culturing human tissue(s).
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Disclosed is a human cell/tissue culturing system including a plurality of incubators, each incubator capable of aseptically storing/culturing cell(s) or tissue(s) derived from a (human) individual and identifying the cell(s) or the tissue(s) during incubation, wherein each incubator comprises a detector corresponding to an individual key, the response of the detector permitting opening/closing of a door of each incubator, the response of the detector of one incubator triggering the interception of the function of the detector(s) of other incubator(s) to consequently inhibit opening/closing of the door(s) of the other incubator(s).
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims benefits from U.S. Provisional Patent Application No. 60/690,774, filed Jun. 15, 2005, the contents of which are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates broadly to non-aerosol sprayers. More particularly, this invention relates to a sustained duration mechanical sprayer.
2. State of the Art
Many household and industrial products are sold in containers that include a sprayer. These products include cleansers, insecticides, polishes, waxes, etc. There are several kinds of sprayers used with these products. Perhaps the most common is the manual push button or trigger operated pump which is seen most frequently on liquid cleansers. It has the advantage of being environmentally friendly (i.e. it does not require a propellant) but the disadvantage of delivering fluid in a series of pulses rather than in a continuous spray. Another well known sprayer is the aerosol can which is sealed and charged with a gas propellant. This sprayer has the advantage that it dispenses fluid in a continuous spray, but has several disadvantages. One disadvantage is that the can cannot be refilled. Another disadvantage is that depending on the gas used to charge the container, the propellant can be environmentally unfriendly. While environmentally friendly propellants do exist, generally, they do not charge as well as the unfriendly gases. Still another popular sprayer is the air pump sprayer seen most frequently with insecticides and liquid garden products. See, for example, U.S. Pat. No. 4,192,464 to Chow. The pump sprayer includes a hand operated air pump which is used to charge the container with compressed air. After it is charged, it operates much like an aerosol can except that the spray head is typically attached to the container by a hose and the container is supplied with a carrying handle. The design permits a gardener to charge the pump while it is on the ground, then carry it in one hand with the handle while the other hand operates the sprayer. The air pump sprayer is environmentally friendly but requires considerable effort to keep charged because air is not as efficient a propellant as environmentally unfriendly gases such as FREON or hydrocarbon gasses. Charging requires that the container be placed on the ground while the gardener pumps the air pump.
Still another type of sprayer is the spring biased sustained duration pump. An example of such a pump is shown in U.S. Pat. No. 5,810,211 to Shanklin et al. Like the air pump described above, these sprayers are typically used for garden products such as insecticides, herbicides, etc. The pump is mounted inside the fluid container and is coupled to a hand held sprayer by a hose (flexible tube). The container is provided with a handle and the pump is primed while holding the container on the ground or on a surface like a table top. The spring biased pump does not utilize air to propel liquid from the container through the nozzle. Rather, a spring biased piston is provided inside a cylinder and connected to a rod which extends through the spring, out of the cylinder and out of the container terminating with a handle. A one-way inlet valve is coupled to the cylinder and the tube from the spray head is coupled to the cylinder via a one-way outlet valve. When the handle is pulled, the piston is moved through the cylinder against the spring, drawing liquid from the container into the cylinder via the one-way inlet valve. When the handle is let go, the spring exerts force against the piston which pressurizes the liquid in the cylinder. The only outlet for the liquid is through the one-way outlet valve into the tube to the spray head which has a spray valve to control dispensing of the liquid. When the spray valve is opened by pushing a button on the hand held sprayer, liquid under pressure flows from the cylinder through the tube to the spray valve, through the spray valve and out a nozzle on the hand held sprayer. The duration of the spray depends on the volume of the cylinder, the force of the spring, and the size/shape of the nozzle. When the spring returns the piston to the starting position, the sustained continuous spray ceases and the pump must be primed again. The amount of liquid in the cylinder can be gauged by the length of the rod extending out of the container.
The spring biased sustained duration pump has many advantages. It is environmentally friendly. It is relatively easy to operate and it is potentially more efficient than the air pump sprayer. However, these sprayers also have some disadvantages. The fact that the container must be held down with one hand while the pump is primed with the other hand is a disadvantage. The fact that the pump cylinder occupies space inside the fluid container is another disadvantage. It is also a disadvantage that the piston rod extends out of the liquid container when the pump is primed. This projecting rod is awkward and can get in the way or get caught on something as the sprayer and container are carried about in use.
Some of the aforementioned disadvantages have been addressed in U.S. Pat. No. 6,415,956 to Havlovitz which proposes locating the spring biased piston and cylinder in the hand held sprayer. However, this does not cure the awkwardness of the piston rod extending into space where it can get in the way or get caught on something. Moreover, in order to accommodate the pump in the hand held sprayer, a rather complex spray valve arrangement is required.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a sustained duration non-aerosol mechanical sprayer.
It is another object of the invention to provide a sustained duration non-aerosol mechanical sprayer which is not contained in a fluid container.
It is a further object of the invention to provide a sustained duration non-aerosol mechanical sprayer which can be primed without placing the container on a surface.
It is also an object of the invention to provide a sustained duration non-aerosol mechanical sprayer which does not have a piston rod which extends from the sprayer when it is primed.
It is an additional object of the invention to provide a sustained duration non-aerosol mechanical sprayer which has a simple spray valve arrangement.
In accord with these objects, which will be discussed in detail below, a sustained duration non-aerosol mechanical sprayer includes a spray head which is screwed onto the top of a bottle to form an integral unit (i.e. not a sprayer coupled to a container by a flexible tube). The spray head includes a spring biased piston in a cylinder (also referred to as an accumulator), a lever charging element which is coupled to the piston via a flexible cable, an inlet check valve between an inlet to the accumulator and the bottle, an outlet tube located on the same side of the piston as the inlet, a nozzle, an outlet valve located in the fluid path between the outlet and the nozzle, and a trigger mechanism which actuates the outlet valve.
According to some embodiments of the invention, the nozzle is located at one end of the spray head and the end of the accumulator to which the inlet and outlet are connected is located at an opposite end of the spray head. Thus, the piston must be moved towards the nozzle to prime the pump and the piston moves away from the nozzle during spraying.
The lever is mounted on the exterior of the spray head and is movable from the front (nozzle end) of the spray head to the rear end of the spray head to charge the pump. A series of pulleys are arranged to guide the flexible cable from the piston to the lever. In this arrangement (which is opposite to what is shown in the prior art), a tube must be provided to couple the outlet of the cylinder at the back of the spray head to the front where the nozzle is located. However, the benefit of this arrangement is that the valve and trigger arrangement can be made simpler. According to alternate embodiments, the accumulator is arranged with its inlet and outlet adjacent to the nozzle. In one embodiment, the outlet valve is integral with the accumulator.
According to the presently preferred embodiment, a load bearing surface supporting a vertical force component sustained when the accumulator is charged is located behind the coupling between the bottle and the spray head. The load bearing surface may be part of the bottle or part of the spray head or both. It may be provided with an anti-rotation detent or a bayonet lock. The load bearing surface relieves stress on the bottle neck and coupling when the lever is pulled back to charge the pump.
Optionally, a thumb support/grip is provided on the top of the spray head. The thumb support/grip allows the user to gain leverage when charging the pump by placing the thumb behind the rest/grip while pulling the charging lever with the fingers.
According to another preferred aspect of the invention, the accumulator is clear and a window is provided on at least one side of the spray head whereby the contents of the accumulator may be viewed. This allows a ready assessment of whether the pump needs to be charged.
According to the most recently preferred embodiment, the accumulator is arranged substantially perpendicular to the vertical axis of the bottle and the inlet and outlet are adjacent the nozzle.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view of a first embodiment of a sprayer according to the invention attached to a bottle according to the invention;
FIG. 2 is a broken perspective view of the front of the sprayer and bottle of FIG. 1 ;
FIG. 3 is a broken perspective view of the rear of the sprayer and bottle of FIG. 1 ;
FIG. 4 is an exploded view of the sprayer of FIG. 1 ;
FIG. 5 is a partially disassembled broken side elevation view of the left side of the sprayer and bottle of FIG. 1 ;
FIG. 6 is a partially disassembled broken side elevation view of the right side of the sprayer and bottle of FIG. 1 ;
FIG. 7 is a broken side elevation view of a second embodiment of a sprayer according to the invention
FIG. 8 is a side elevation view of a third embodiment of a sprayer according to the invention attached to a bottle according to the invention;
FIG. 9 is a broken perspective view of the rear of the sprayer and bottle of FIG. 8 ;
FIG. 10 is a broken perspective view of the front of the sprayer and bottle of FIG. 8 ;
FIG. 11 is an exploded view of the sprayer of FIG. 8 ;
FIG. 12 is a partially disassembled broken side elevation view of the left side of the sprayer and bottle of FIG. 8 ;
FIG. 13 is a partially disassembled broken side elevation view of the right side of the sprayer and bottle of FIG. 8 ;
FIG. 14 is a broken side elevation view of a fourth embodiment of a sprayer according to the invention;
FIG. 15 is a partially disassembled broken side elevation view of a fifth embodiment of a sprayer according to the invention;
FIG. 16 is a partially disassembled perspective view of a sixth embodiment of a sprayer according to the invention;
FIG. 17 is a side elevation view of a seventh embodiment of a sprayer according to the invention attached to a bottle according to the invention;
FIG. 18 is an exploded view of the sprayer of FIG. 17 ;
FIG. 19 is a partially disassembled broken side elevation view of the right side of the sprayer and bottle of FIG. 17 ;
FIG. 20 is a partially disassembled broken side elevation view of the left side of the sprayer and bottle of FIG. 17 ;
FIG. 21 is a broken perspective view of the front of the sprayer and bottle of FIG. 17 ;
FIG. 22 is a broken perspective view of the rear of the sprayer and bottle of FIG. 17 ;
FIG. 23 is a broken rear elevation view of the sprayer and bottle of FIG. 17 ; and
FIG. 24 is a broken front elevation view of the sprayer and bottle of FIG. 17 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1-6 illustrate a first embodiment of a sprayer 10 and a bottle 12 . The sprayer 10 generally includes an ellipsoidal body having left and right half shells 14 , 16 . Each half shell has an upper vane 14 a , 16 a and a lower wing 14 b , 16 b . At least one of the half shells, e.g. 14 has a side window 14 c . The two vanes 14 a , 16 a join to define a groove 18 which extends from the front of the body to a point short of the rear as seen best in FIG. 3 . The front of the body is provided with an adjustable nozzle 20 and the bottom of the body is provided with a trigger 22 , a bottle coupling 24 , and a load bearing surface 26 . A pull lever 28 is mounted above the wings 14 b , 16 b . The lever 28 is a generally inverted U-shape having two legs 28 a , 28 b and a cross member 28 c . The cross member 28 c defines an upwardly extending handle 28 d and a downwardly extending rudder 28 e ( FIG. 3 ) which engages and rides in the groove 18 . The ends of the legs 28 a , 28 b have lugs or bosses 28 f , 28 g ( FIG. 4 ) extending inward therefrom. These lugs or bosses engage holes 14 d , 16 d in the left and right half shells 14 , 16 and define the pivot axis of the lever 28 . The pivot axis is preferably aligned close to or on the vertical axis of the bottle coupling 24 .
The bottle 12 has a lower tank area 30 and an upper neck 32 which is dimensioned to be grasped by an adult human hand. The neck 32 has a threaded coupling which is hidden under the coupling 24 of the sprayer 10 . Behind the coupling the bottle has a load bearing surface 34 which abuts the load bearing surface 26 on the sprayer 10 . As illustrated, the load bearing surface 34 is a plateau on a stem 35 which rises behind the coupling 24 to abut a planar surface 26 on the sprayer. The stem 35 and the load bearing surface 34 are preferably generally semi-circular and have a thickness sufficient to support a vertical load during backward movement of the lever 28 . It will be appreciated, however, that the load bearing surface of the sprayer could be at the bottom of a downward extension and the load bearing surface on the bottle could be a planar surface below it. Another feature of the bottle 12 is a finger rest 36 located below and between the trigger 22 and the coupling 24 of the sprayer. In use the user grasps the neck 32 with middle finger, ring finger and pinky while using the index finger to pull the trigger. The finger rest 36 prevents the user's middle finger from riding up the neck 32 into the path of the trigger 22 .
From the foregoing and the following, those skilled in the art will appreciate that the load bearing surface arrangements of the invention may be useful in other sprayers where the charging element exerts a force on the bottle with a vertical load component during charging. This clearly applies to most levers and may apply to other charging elements
Turning now to FIGS. 4-6 , the inner workings of the sprayer 10 are shown in detail. The sprayer includes an accumulator 40 (a piston cylinder), a piston 42 , a piston retainer 44 , a biasing spring 46 , an accumulator cap 48 , and a pull cable 50 . These components are assembled by extending the pull cable 50 through the cap 48 and the spring 46 to the retainer 44 . One end of the cable 50 is attached to the retainer 44 which is coupled to the piston 42 . The piston 42 is inserted into the accumulator 40 with the retainer 44 and the cable 50 following it. The spring 46 is inserted into the accumulator 40 behind the retainer 44 and the accumulator is closed by the cap 48 . The free end of the cable 50 extends through the cap 48 and is attached to the pull lever 28 . At the end of the accumulator opposite the cap 48 is a fluid inlet/outlet 52 (seen best in FIGS. 5 and 6 ) to which a manifold 54 is attached. Two hoses 56 , 58 are coupled to the manifold 54 as seen best in FIG. 6 . Inlet hose 56 is also coupled to a ball check manifold 60 which includes a plastic ball 62 and a ball check fitting which operate in conjunction to form a one-way valve which is coupled to an intake tube (not shown) that extends down into the fluid in the bottle. Liquid hose 58 is coupled to the inlet of one cylinder 66 a (liquid valve) of a double valve body 66 . Two additional hoses 68 and 70 are provided. Vent hose 68 couples the inlet of the second cylinder 66 b (air valve) of the double valve body 66 and extends into the interior of the bottle via the manifold 60 . Liquid hose 70 couples the outlet of cylinder 66 a to a nozzle adapter 72 which is coupled to the nozzle 20 . Each of the cylinders 66 a , 66 b of the double valve body is provided respectively with a spring 74 a , 74 b , a flared piston 76 a , 76 b , and a piston cap 78 a , 78 b , the latter of which are engaged by the trigger 22 . In the resting state the springs 74 a , 74 b bias the pistons to a position where the flares on the pistons block fluid flow through the cylinders 66 a and 66 b . When actuated by the trigger 22 , the flares of the pistons are moved into larger portions of the cylinders, thereby permitting fluid flow through the cylinders.
From the foregoing, those skilled in the art will appreciate how the sprayer works, namely as follows. The spray pump is charged by moving the pull handle 28 (about its pivot axis) from the front of the sprayer toward the rear. This causes the cable 50 to be pulled out of the accumulator 40 pulling the piston 42 against the spring 46 away from the fluid inlet/outlet 52 , and causing a vacuum within the accumulator 40 and the hoses 56 and 58 . Since the hose 56 is coupled to the one way valve assembly 60 , 62 , 64 , it causes the ball 62 to rise, opening the valve and allowing fluid to enter the hose 56 from the bottle into the accumulator 40 . The vacuum in hose 56 does nothing because the end of hose 56 is blocked by the flared piston in the valve cylinder 66 a . When the handle 28 is released or moved as far back as it can go (limited by the length of the cable 50 as well as the length of the groove 18 ) and released, the spring 46 will exert a force against the piston 42 in the accumulator 40 compressing the fluid therein as well as the fluid in the hose 56 which causes the ball 62 to drop, sealing off the fluid path into the bottle. Fluid from the accumulator 40 will be fed under pressure through the manifold 54 into the hose 58 but goes no further because of the piston blocking the cylinder 66 a . When the trigger 22 is squeezed, the piston in the cylinder 66 a is moved, allowing fluid flow therethrough. Fluid under pressure in the accumulator moves through the hose 58 through the cylinder 66 a , through the hose 70 , into the nozzle adapter 72 and out through the nozzle 20 . As fluid is ejected from the accumulator, the spring urges the piston towards the manifold until all of the fluid is expelled from the accumulator and the spring and the pull handle move toward their original position. When the sprayer is spraying, the piston in cylinder 66 b is moved allowing air to enter the bottle and replace the fluid which was previously drawn into the accumulator.
As seen best in FIGS. 5 and 6 , the accumulator 40 is clear and as seen best in FIG. 4 , both the half shells 14 and 16 are provided with windows 14 c , 16 c . The windows allow viewing of the contents of the accumulator. Also, it will be noted that in the illustrated embodiment, the load bearing surfaces 26 , 34 are accompanied by anti-rotation flanges 34 a , 34 b on the bottle. It will be appreciated that the load bearing surfaces relieve strain on the coupling 24 when the handle 28 is pulled back and that the anti-rotation flanges align the load bearing surfaces as well as align the trigger 22 with the finger rest 36 .
Referring now to FIG. 7 , a second embodiment of a sprayer 110 is substantially the same as the sprayer 10 described above with similar reference numerals (increased by 100 ) referring to similar parts. According to this embodiment, a thumb support 119 is formed by extensions of the fin portions 114 a , 116 a . The thumb support is located at the end of the groove 118 . When charging the sprayer, the user places his/her thumb behind the thumb support 116 , grabs the lever with their fingers, and pulls back on the lever using the thumb support for leverage. If the sprayer is charged this way, reduced stress is placed on the coupling 124 .
FIGS. 8-10 are similar to FIGS. 1-3 with similar reference numerals (increased by 200 ) referring to similar parts. On the exterior, the sprayer 210 is similar to the sprayer 10 and the bottles 12 and 212 are identical. The only apparent difference in the appearance of the sprayers 10 and 210 is the size and shape of the fins 214 a , 216 a as compared to the fins 14 a , 16 a and also the shape of the lever 228 as compared to the lever 28 .
FIGS. 11-13 illustrate the similarities and the differences between the sprayer 210 and the sprayer 10 shown in FIGS. 4-6 . Similar reference numerals (increased by 200 ) refer to similar parts. Where there has been a significant departure in the design, dissimilar reference numerals have been used. The sprayer 210 includes an accumulator 240 (a piston cylinder), a piston 242 , a piston retainer 245 , a pulley 247 , a biasing spring 246 , an accumulator cap 249 , and a pull cable 251 . The piston retainer 245 is different from the piston retainer 44 shown in FIG. 4 in that it is adapted to carry the pulley 247 . As will be described in more detail in the next paragraph, the accumulator cap 249 and the pull cable 251 are different from the cap 48 and cable 50 shown in FIG. 4 .
These components are assembled by extending one end of the pull cable 251 through the cap 249 and through the spring 246 around the pulley 247 , back through the spring 246 and fastening it to the cap 249 . The other end of the cable 251 extends through an opening in the cap 249 and is coupled to the lever 228 . The piston 242 is inserted into the accumulator 240 with the retainer 245 , pulley 247 and the cable 251 following it. The spring 246 is inserted into the accumulator 240 behind the retainer 245 and the accumulator is closed by the cap 249 .
As seen best in FIGS. 12 and 13 , the end of the accumulator opposite the cap 249 is a fluid inlet/outlet 252 to which a manifold 254 is attached. Two hoses 256 , 258 are coupled to the manifold 254 . Inlet hose 256 is also coupled to a ball check manifold 260 ( FIG. 11 ) which includes a plastic ball 262 and a ball check fitting 264 which operate in conjunction to form a one-way valve which is coupled to an intake tube (not shown) that extends down into the fluid in the bottle. Outlet hose 258 is coupled to the inlet of one cylinder 266 a (liquid valve) of the double valve body 266 . Two additional hoses 268 and 270 are provided. Vent hose 268 couples the inlet of the second cylinder 266 b (air valve) of the double valve body 266 and extends into the interior of the bottle via the manifold 260 . Liquid hose 270 couples the outlet of the first cylinder 266 a (liquid valve) of the double valve body to a nozzle adapter 272 which is coupled to the nozzle 220 . As seen best in FIG. 11 , each of the cylinders 266 a , 266 b of the double valve body is provided respectively with a spring 274 , a flared piston 276 , and a piston cap 278 , the latter of which are engaged by the trigger 222 . In the resting state the springs 274 bias the flared pistons to a position where the flares on the pistons block fluid flow through the cylinders 266 a , 266 b . When actuated by the trigger 222 , the flares on the pistons are moved into larger portions of the cylinders, thereby permitting fluid flow through the cylinders.
From the foregoing, those skilled in the art will appreciate how the sprayer works, namely as follows. The spray pump is charged by moving the pull handle 228 from the front of the sprayer toward the rear, rotating it about its pivot axis. This causes the cable 251 to be pulled out of the accumulator 240 rotating over the pulley 247 pulling the piston 242 against the spring 246 away from the fluid inlet/outlet 252 , and causing a vacuum within the accumulator 240 and the hoses 256 and 258 . Since the hose 256 is coupled to the one way valve assembly 260 , 262 , 264 , it causes the ball 262 to rise, opening the valve and allowing fluid to enter the hose 256 from the bottle into the accumulator 240 . The vacuum in hose 256 does nothing because the end of hose 256 is blocked by the flared piston in the valve cylinder 266 a . When the handle 228 is released or moved as far back as it can go (limited by the length of the cable 250 as well as the length of the groove 218 ) and released, the spring 246 will exert force against the piston 242 in the accumulator 240 compressing the fluid therein as well as the fluid in the hose 256 which causes the ball 262 to drop, sealing off the fluid path into the bottle. Fluid from the accumulator 240 will be fed under pressure through the manifold 254 into the hose 258 but goes no further because of the piston blocking the cylinder 266 a . When the trigger 222 is squeezed, the piston in the cylinder 266 a is moved, allowing fluid flow therethrough. Fluid under pressure in the accumulator moves through the hose 258 through the cylinder 266 a , through the hose 270 , into the nozzle adapter 272 and out through the nozzle 220 . As fluid is ejected from the accumulator, the spring urges the piston towards the manifold until all of the fluid is expelled from the accumulator and the spring and the pull handle assume their original position or until the trigger is released.
Those skilled in the art will appreciate that this embodiment provides a mechanical advantage by way of the pulley 247 . Thus, the force needed to charge the pump is lessened.
FIG. 14 illustrates a fourth embodiment of a sprayer 310 according to the invention which is similar to the first embodiment with similar reference numerals (increased by 300 ) referring to similar features. The main difference in this embodiment is that the load bearing surface 334 of the bottle 332 is a planar surface behind the coupling 324 and the planar surface 326 on the sprayer is at the bottom of a downward depending extension 327 . The extension 327 has a generally semi-circular cross section and a thickness sufficient to withstand the vertical component of force exerted on it when the lever 328 is pulled backward to charge the pump.
FIGS. 15 and 16 show fifth and sixth embodiments, respectively. These embodiments are, in many ways, similar to the first embodiment with similar reference numerals (increased by 400 and 500 , respectively) referring to similar features. The main difference in these embodiments is that the accumulator 440 , 540 is arranged with its inlet and outlet adjacent to the nozzle 420 , 520 .
Referring now to FIG. 15 , the sprayer 410 includes a nozzle 420 , a trigger 422 , a downward depending extension 427 terminating with a load bearing surface 426 and an interlock 429 . A charging lever 428 and a thumb support 419 are located on the top of the sprayer. An accumulator 440 is located inside the sprayer. The accumulator includes a piston 442 and a spring 446 . A flexible cable 450 is coupled at one end to the piston 442 and at the other end to the charging lever 428 . A plurality of pulleys 451 , 453 , 455 guide the cable 450 from the back of the accumulator to the front. An inlet and outlet manifold 454 is located between the accumulator 440 and the nozzle 420 . Inlet hose 456 couples the manifold 454 with inlet check valve 460 . An outlet valve 466 a having a piston 467 a is coupled between the manifold 454 and the nozzle 420 . An air relief valve 466 b having a piston (not shown) is provided adjacent to the inlet check valve 460 . An upper arm 422 a of the trigger 422 engages the piston 467 a of the outlet valve 466 a and a lower arm 422 b of the trigger engages the piston of the air relief valve 466 b . The sprayer is operated in the same manner as the sprayers described above. The lever 428 is pulled back to charge the accumulator and the trigger 422 is pulled to dispense fluid through the nozzle 420 . Actuation of the trigger 422 causes the upper arm 422 a to move downward thereby pulling the piston 467 a downward and opening the outlet valve 466 a allowing liquid to flow from the accumulator through the nozzle 420 . Simultaneously, the lower arm 422 b moves backward engaging the piston of the air relief valve 466 b allowing a volume of air equivalent to the volume of liquid in the accumulator to enter the bottle (not shown).
FIG. 16 shows a sprayer 510 which is similar to the sprayer 410 with similar reference numerals (increased by 100 ) referring to similar features. The difference between the sprayer 510 and the sprayer 410 is that the outlet valve 566 a is coupled directly to the accumulator 540 and the inlet hose 556 enters the manifold 554 along side the valve 566 a rather than behind it as shown in FIG. 15 .
FIGS. 17 through 24 show a seventh embodiment of a sprayer 610 and bottle 612 . This embodiment is similar to the fifth and sixth embodiments and similar elements will be referred to with similar reference numerals (increased by 200 and 100 respectively). The sprayer 610 generally includes an ellipsoidal body having left and right half shells 614 , 616 . Each half shell has an upper vane 614 a , 616 a and a lower wing 614 b , 616 b . At least one of the half shells, e.g. 616 has a side window 616 c as seen best in FIGS. 21 and 22 . The two vanes 614 a , 616 a join to define a groove 618 which extends from the front of the body to a point short of the rear as seen best in FIGS. 21 and 22 . The front of the body is provided with an adjustable nozzle 620 and the bottom of the body is provided with a trigger 622 , a bottle coupling 624 , and a load bearing surface 626 . A pull lever 628 is mounted above the wings 614 b , 616 b . The lever 628 is a generally inverted U-shape having two legs 628 a , 628 b and a cross member 628 c . The cross member 628 c defines an upwardly extending handle 628 d and a downwardly extending rudder (not shown) which engages and rides in the groove 618 . The ends of the legs 628 a , 628 b have holes 628 f , 628 g ( FIG. 18 ) which are engaged by screws 629 a , 629 b . These screws engage holes 614 d , 616 d in the left and right half shells 614 , 616 and define the pivot axis of the lever 628 . The pivot axis is preferably aligned close to or on the vertical axis of the bottle coupling 624 .
As seen best in FIG. 17 , the bottle 612 has a lower tank area 630 and an upper neck 632 which is dimensioned to be grasped by an adult human hand. The neck 632 has a threaded coupling which is hidden under the coupling 624 of the sprayer 610 . Behind the coupling the bottle has a load bearing surface 634 which abuts the load bearing surface 626 on the sprayer 610 . As illustrated, the load bearing surface 634 is a plateau on the neck 632 stepped down from the threaded coupling. As seen best in FIGS. 17 , 21 , and 22 the load bearing surface 634 is adjacent a vertical planar surface 633 which engages a similar surface 631 on the sprayer 610 which together form an anti-rotation structure.
Turning now to FIGS. 18-20 , the inner workings of the sprayer 610 are shown in detail. The sprayer includes an accumulator 640 (a piston cylinder), a piston 642 , a piston retainer 644 , a biasing spring 646 , and a pull cable 650 . The half shells 614 , 616 , when assembled, form a slotted retainer wall 648 which abuts the spring 646 . These components are assembled by extending the pull cable 650 through the slotted retainer wall 648 and the spring 646 to the retainer 644 . One end of the cable 650 is attached to the retainer 644 which is coupled to the piston 642 . The piston 642 is inserted into the accumulator 640 with the retainer 644 and the cable 650 following it. The spring 646 is inserted into the accumulator 640 behind the retainer 644 and the accumulator is closed by the slotted retainer wall 648 . The free end of the cable 650 extends through the slot in the wall 648 and is attached to the pull lever 628 . At the forward end of the accumulator 640 is a fluid inlet/outlet 652 to which a manifold 654 is attached via an elbow 656 . The manifold 654 is coupled to the bottle coupling 624 with a gasket 655 . An inlet tube 656 is coupled to the manifold 654 via a ball check valve assembly 660 , 662 .
Two valves are provided: one in the fluid outlet 652 and the other in the manifold 654 which acts as an air inlet for the bottle 612 . The outlet valve includes a piston 676 a and a piston adapter 678 a . The piston is mounted in a cylinder in the fluid outlet 652 and is coupled to the adapter 678 a which is coupled to the trigger 622 . The air inlet valve includes a spring 674 , a piston 676 b , and an adapter 678 b . The spring and the piston are mounted in a cylinder in the manifold 654 and the piston is coupled to the adapter 678 b which is coupled to the trigger 622 . The spring 674 biases the valves shut and the trigger forward. When the trigger is pulled backward, both valves open allowing fluid to escape from the accumulator 640 through the nozzle 620 and allowing air to enter the bottle 612 . A second check valve ball 665 is mounted in the manifold and operates when the sprayer and bottle are inverted while operating to prevent leakage through the vent.
There have been described and illustrated herein several embodiments of a sustained duration non-aerosol mechanical sprayer. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. It will therefore be appreciated by those skilled in the art that modifications could be made to the provided invention without deviating from its spirit and scope as claimed.
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A sustained duration non-aerosol mechanical sprayer includes a spray head which is screwed onto the top of a bottle. The spray head includes a spring biased piston in a cylinder, a lever which is coupled to the piston via a flexible cable. A thumb support is provided to facilitate movement of the lever. A load bearing surface is provided to absorb force exerted by moving the lever. Anti-rotation structure is provided to locate the spray head relative to the bottle. A window in the spray head allows the contents of the cylinder to be viewed. According to some embodiments, the nozzle is located at one end of the spray head and the end of the accumulator to which the inlet and outlet are connected is located at an opposite end of the spray head.
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TECHNICAL FIELD
The present invention relates generally to a dispensing apparatus and more particularly relates to beverage dispensers or others types of devices that initiate a sanitation cycle based upon several predetermined factors.
BACKGROUND OF THE INVENTION
Dispensing machines, such as those for beverages and confections, generally have product delivery systems that should be sanitized on a regular basis. Specifically, the machine may need to be sanitized on a daily, weekly, monthly, and/or semi-annually basis. For example, certain low acid beverages, such a frozen beverages, may have a pH level that may permit microorganism growth over a certain amount of time even given the cold temperatures involved. Laboratory testing may determine the growth parameters for a given product so as to determine a relevant time frame. The sanitation cycles generally are set on this determined time frame plus a margin of safety. Thus, most known equipment is sanitized on a straight time interval basis.
This time-based approach, while effective, generally does not compensate for varying product demand levels in a given location. Higher demand and usage levels generally require less sanitation due to the inverse ratio between product dwell time and product demand rate. In other words, because the product is in the dispenser for less time, there is less opportunity for microorganism growth.
Further, this time-based approach generally does not compensate for unscheduled shutdowns. A beverage dispenser generally must be sanitized immediately following any type of unscheduled shutdown. Known beverage dispensers, however, may not compensate for, or take into account, the additional sanitation cycle before initiating a regularly scheduled cycle.
What is desired, therefore, is a dispenser that takes into account other factors beyond the time between sanitation cycles. Preferably, the system can be adaptive to the nature of the product, demand levels, equipment functionality, time intervals, or other factors.
SUMMARY OF THE INVENTION
The present application thus describes a method for altering an initiation time of an apparatus sanitation cycle based upon a base line flow rate. The method may include determining an actual flow rate through the apparatus, comparing the actual flow rate to the base line flow rate, and delaying the initiation time of the apparatus sanitation cycle if the actual flow rate exceeds the base line flow rate.
The delaying step may include delaying the initiation time of the apparatus sanitation cycle if the actual flow rate exceeds the base line flow rate by a predetermined volume. The delaying step also may include initiating the apparatus sanitation cycle at a predetermined time if the actual flow rate does not exceed the base line flow rate by a predetermined volume. The method further may include initiating the apparatus sanitation cycle at a predetermined time if the actual flow rate does not exceed the base line flow rate.
The apparatus sanitation cycle may include defrosting the apparatus, cleaning the apparatus, rinsing the apparatus, sanitizing the apparatus, and/or refilling the apparatus. The comparing step may include determining a type of product loaded in the apparatus and looking up data on the type of product. The method further may include initiating the apparatus sanitation cycle if a not to exceed date is reached.
The present application further may describe a dispenser. The dispenser may include a source of product, a flow meter to determine the volume of the product flowing through the dispenser, a sanitation system, and a controller. The controller may activate the sanitation system based upon the volume of product flowing through the dispenser as measured by the flow meter.
The flow meter may include a paddlewheel. The source of product may include concentrate and water and the flow meter may determine the volume of the concentrate and the water flowing through the dispenser. The dispenser further may include a freezing chamber.
The controller may include data on the source of product. The controller may compare the volume of product flowing through the dispenser to a base line flow rate. The controller may activate the sanitation system at a predetermined time if the volume of product flowing through the dispenser does not exceed the base line flow rate. The controller also may activate the sanitation system when a not to exceed date is reached.
The source of product may include a radio frequency identification tag. The radio frequency identification tag may include data on a product therein.
A further method described herein provides for activating an apparatus sanitation cycle. The method may include determining an actual flow rate through the apparatus over a predetermined period, comparing the actual flow rate to a base line flow rate over the predetermined period for a given product, and activating the sanitation cycle if the actual flow rate is less than the base line flow rate.
These and other features of the present invention will become apparent upon review of the following detailed description when taken in conjunction with the drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram schematically illustrating an example of a frozen beverage machine that may be used with the invention as is described herein.
FIG. 2 is a block diagram showing an example of the process methodology as is described herein.
DETAILED DESCRIPTION
Referring now to the drawings in which like numbers refer to like elements throughout the several views, FIG. 1 shows an example of a beverage dispenser system 10 that may be used with the sanitation method as is described herein. The beverage dispenser system 10 may be a frozen beverage dispenser. Although a frozen beverage dispenser is shown, almost any type of dispensing system may be used herein. Suitable frozen beverage dispensers are show in, for example, commonly owned U.S. Pat. No. 6,604,654, entitled “THREE-BARREL FROZEN PRODUCT DISPENSER”, incorporated herein by reference. Another example is shown in U.S. Pat. No. 6,625,993, entitled “FROZEN BEVERAGE MACHINE AND METHOD OF OPERATION”, also incorporated herein by reference. This reference also describes a “clean in place” system, i.e., an automatic, time based, sanitation cycle.
Similar to that described in U.S. Pat. No. 6,625,993, the beverage dispenser 10 may include a source of water 20 ; a source of syrup 30 (or other types of concentrate or additives); a source of gas 40 , such as a source of compressed carbon dioxide; and a source of cleaning solution 50 , such as sanitizer and/or detergent. A process flow block 60 may control the flow of these fluids. The combination of water, syrup, and gas from the sources 20 , 30 , 40 may be mixed as appropriate within a mixing block 70 and then frozen in a freezing chamber 80 . The freezing chamber 80 may be in communication with a conventional refrigeration system 90 . Once sufficiently mixed or frozen, a beverage may be dispensed via a nozzle 100 .
A controller 110 may govern operation of the beverage dispenser 10 as a whole. The controller 110 may be a conventional microprocessing device capable of executing software commands. The controller 110 may include an internal clock or the controller 110 may be in communication with any other type of time system. A data file 120 may be accessible by the controller 110 . The data file 120 may be any type of data storage system. The controller 110 and/or the data file 120 may be local or remote.
As described above, with known “clean in place” system, the sanitation cycle may begin upon the controller 110 determining that the predetermined time interval since the previous cleaning has occurred. Likewise, the controller 110 may start the sanitation cycle due to certain other events, such as a loss of power. Generally described, the sanitation cycle may include the steps of defrost, clean, rinse, sanitize, dispense, and refill. Other types of sanitation methods may be used herein. The sanitation cycle may include pumping the cleaning fluid through the beverage dispenser 10 as a whole.
FIG. 2 shows a flowchart of an example of the sanitation method 200 as is described herein. The sanitation method 200 may be executed by conventional software code running on the controller 110 in association with the data file 120 or other source of memory means. Remote control means also may be used herein.
To the extent not present in the beverage dispenser system 10 , one or more flow meters 210 may be positioned therein. The flow meter 210 may be positioned in any convenient location within the system 10 as a whole such as between the sources 20 , 30 , 40 and the process flow block 60 , between the freezing barrel 80 and the nozzle 100 , or in any other convenient location. The flow meter 210 may be a conventional paddlewheel or a similar type of measuring or counting device. Any other type of flow or velocity measuring device may be used, such as laser velocimeters, ultrasound, and similar devices. The flow rate may be measured directly or indirect methods also may be used. The term “flow meter” is intended to refer to any such measurement device.
The sanitation method 200 may begin at step 220 with the startup of the beverage dispenser system 10 as a whole. At step 230 , the controller 110 receives input from the flow meter 210 as to the flows from the water, syrup, and/or gas sources 20 , 30 , 40 ; the nozzle 100 ; and/or from other locations within the system 10 as a whole. At step 240 , the controller 110 looks up the relevant parameters in the data file 120 for a given product and/or time. At step 250 , the controller 110 compares the flow data from the input step 230 with the parameters found in the data file 120 in the lookup routine of step 240 . Specifically, the flow rate through the system 10 as a whole is compared to the predetermined time parameters. Based upon this comparison at step 250 , a decision is made at step 260 as to whether the flow rates or the given time intervals require the initiation of a sanitation cycle. If not, the routine returns to the input step 230 . If so, the controller 110 initiates a sanitation cycle at step 270 .
The data file 120 may contain the conventional data as to the time intervals between normal sanitation cycles based upon the laboratory analysis for a given product. As described above, these cycle intervals are time based and factor in additional safety concerns. For example, laboratory testing may indicate that the dispenser 10 can run for thirty-five (35) days under minimal draw rates for a given product and stay within standards.
Should the dispenser 10 experience higher draw rates more in line with real sales, however, the sanitation cycle could be lengthened. For example, if a daily or weekly flow rate exceeds a baseline figure, then the cycle may be extended for a predetermined number of days. This longer period could range, for example for about sixty (60) to about ninety (90) days depending upon the nature of the product. Lengthening the cycles would waste less product, sanitizer, and mechanical component lifetime without jeopardizing safety.
The data file 220 also may have a “not to exceed” date. In other words, the controller 110 may start the sanitation cycle after a given number of days regardless of the flow rate therethrough.
The method 200 also may accommodate unscheduled stops in a more economical fashion. For example, if a power loss occurred two days ago and a sanitation cycle was preformed but the next sanitation cycle is due today, the controller 110 will recognize that the sanitation cycle is to be measured from the last event as opposed to starting a new cycle today.
The controller 110 may be able to determine the nature of the source of the syrup 30 based upon user input or the system 10 may be able to sense the nature of the product via a RFID (radio frequency identification) tag 300 or similar types of identification means. Based upon the nature of the syrup or other source, the controller 110 may access a different file in the data file 120 . As a result, the system 10 as a whole can accommodate the use of different types of syrup sources 30 or other types of input. Further, the RFID tag 300 and the nature of the syrup also may effect the dispensing ratio and other product parameters of the system 10 as a whole.
It should be understood that the foregoing relates only to the preferred embodiments as are described herein and that numerous changes and modifications may be made herein without departing from the general spirit and scope of the invention as described by the following claims and the equivalents thereof.
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A method for altering an initiation time of an apparatus sanitation cycle based upon a base line flow rate. The method may include determining an actual flow rate through the apparatus, comparing the actual flow rate to the base line flow rate, and delaying the initiation time of the apparatus sanitation cycle if the actual flow rate exceeds the base line flow rate.
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TECHNICAL FIELD
This invention relates to mobile wireless telecommunications systems.
BACKGROUND OF THE INVENTION
The dealer-locator service connects a caller to the one of a plurality of business locations of the called party (the "dealer") which is closest to the caller. The dealer-locator service is well-known for stationary calling stations (i.e., conventional wired-in-place telephones). The service uses the calling telephone number to determine the caller's geographical location, and from that information determines the called party's business location that is geographically closest to the caller. Illustrative implementations of the dealer-locator service are disclosed in U.S. Pat. Nos. 4,757,267 and 5,136,636.
While the known dealer-locator service works well for stationary communications stations, it is practically useless for mobile (i.e., portable) communications stations, such as mobile cellular radiotelephones and personal communications services (PCS) wireless handsets. The reason is that the known service uses the calling station's telephone number to derive the caller's geographical location. But the geographical location of a mobile station changes while its telephone number remains the same. Hence, the telephone number of a mobile station is not representative of its location.
Schemes for determining the geographical location of a mobile station are known. One scheme, disclosed in U.S. Pat. No. 5,293,645, uses relative transmission-propagation delays from a mobile station to a plurality of base stations to determine the mobile station's location by using triangulations or other geographical intersection techniques. Consequently, this scheme works only when the mobile station is in simultaneous communication with a plurality (generally at least three) of base stations. Another scheme, disclosed in U.S. Pat. No. 5,479,482, equips each mobile station with a global satellite positioning (GPS) device that determines and reports the mobile station's geo-coordinates, which can then be converted into location information. Consequently, this scheme works only for specially-equipped mobile stations, but not for conventional mobile stations without a GPS device. Neither scheme is therefore useful for implementing a ubiquitous dealer-locator service for conventional mobile telecommunications systems.
SUMMARY OF THE INVENTION
This invention is directed to solving these and other problems and disadvantages of the prior art. Generally according to the invention, when a mobile terminal initiates a call to a dealer-location service, an identification of the base station through which the call is made, rather than the telephone number of the calling station, is used to determine a business location of the dealer that is in the vicinity of the calling station. The address of the determined location is then reported to the caller, and/or the call is extended to the determined location.
According to one aspect of the invention, in a mobile communications system that includes at least one mobile communications station and a plurality of base stations each for communicating with mobile communications stations in a different geographical area, a dealer-locator arrangement serves a plurality of business locations of a service provider that are located in a plurality of the geographical areas. In response to a communication from a mobile communications station that identifies the service provider, the arrangement determines which one of the plurality of base stations is presently communicating with the mobile communications station. Illustratively, this determination is accomplished by the mobile communications system's switching center, or MTSO. The arrangement then uses this determination to determine which one of the plurality of business locations is within a vicinity of the one base station. Illustratively, this is effected via a database lookup in a database whose contents correlate the base stations each with at least one of the business locations that is in the vicinity of the base station. The arrangement then either causes the determined business location (e.g., its address) to be reported to the mobile communications station, or causes a communication (e.g., a phone call) from the mobile communications station to be extended to the determined business location (e.g., to a telephone number that is associated in the database with that business location), or both.
The user of the mobile communications station is thus informed of the whereabouts of, or is connected to, a business location of the service provider that is likely to be one of the closest, if not the closest, to the user at the present time, even though the user is on the move wherefore the user's own geographical position cannot be determined from the user's calling telephone number.
These and other advantages and features of the present invention will become more apparent from the following description of an illustrative embodiment of the invention considered together with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a block diagram of an illustrative mobile telecommunications system that includes an illustrative embodiment of the invention;
FIG. 2 is a block diagram of records of a home location register database of the system of FIG. 1;
FIG. 3 is a block diagram of databases of a dealer locator database of the system of FIG. 1;
FIGS. 4-5 are a functional flow diagram of operations of the system of FIG. 1 in effecting the illustrative embodiment of a dealer-locator service; and
FIG. 6 is a functional flow diagram of operations of the system of FIG. 1 in programming a database of FIG. 3.
DETAILED DESCRIPTION
FIG. 1 shows a mobile wireless telephone system comprising a mobile telephone switching center or office (MTSO) 41 connected to the public service telephone network (PSTN) 60 and to a plurality of base stations 20-23, and providing through each base station 20-23 radiotelephone service to mobile telephones 40 in the base station's geographical service area (cell) 10-13, respectively. Associated with MTSO 41 is a home location register database (HLR) 42 of conventional call records of active calls. As shown in FIG. 2, for each active call, MTSO 41 conventionally creates in HLR a record 201 that contains at least a call identifier (ID) entry 202 by which MTSO 41 distinguishes the call from other calls, a telephone number entry 203 of the calling or called mobile telephone 40 that is involved in the identified call, and a base station ID entry 204 of one of the base stations 20-23 that is presently serving the identified mobile telephone 40 during the identified call. Mobile telephones 40 need not have this MTSO 41 as their home MTSO; they can be roaming units outside of their home area.
Located in various places within the geographical areas served by base stations 20-23 are multiple business locations of various service providers ("dealers"). For purposes of this application, a service provider is defined broadly to encompass substantially any multi-location entity or group of entities. For example, a service provider may be a particular pizza restaurant chain, automobile gas and service stations of one or more oil companies, police stations, automatic teller machines (ATMs) of one or more banks, etc. For ease of illustration, FIG. 1 shows four locations 30-33 of one service provider and three locations 50-52 of a second service provider. Some service locations (e.g., pizza restaurants) may have associated telephones, while other service locations (e.g., ATMs) may not have associated telephones. In this illustrative example, locations 30-33 are assumed to be equipped with telephones, while locations 50-52 are assumed to not be equipped with telephones.
According to the invention, there is provided in the system of FIG. 1 an intelligent peripheral (IP) 43, such as a Lucent Technologies Inc. Conversant® interactive voice response system, and a dealer-locator database (DB) 44 which provide dealer-locator services to mobile telephones 40. IP 43 may be connected directly to MTSO 41 and HLR 42 and function as an adjunct processor thereof. Alternatively, IP 43 may be located remotely from MTSO 41 and HLR 42 and be respectively connected thereto via telephone lines of PSTN 60 and a signaling system 7 (SS7) link. IP 43 may also be co-located with and directly connected to DB 44, but is preferably connected to DB 44 via an SS7 link 45. IP 43 is a stored-program-controlled machine that conventionally includes an interface for communicating with other entities of the system of FIG. 1 and including speech recognition and speech synthesis circuitry such as a digital signal processor (DSP), a memory for storing control programs, and a control processor which executes the control programs out of memory to control the operation of IP 43.
As shown in FIG. 3, DB 44 comprises a collection of one or more databases 300-301, one for each service provider served by the system of FIG. 1. For example, DB 44 comprises a database 300 for a service provider 3 (e.g., a pizza restaurant chain) and a database 301 for a service provider 5 (e.g., an ATM provider). Each database 300-301 comprises a plurality of records 302 that correlate base stations with a dealer's business locations. Each record 302 has at least an entry 303 containing the ID of a base station 20-23 and an entry 304 containing the address of a location 30-33 or 50-52 of the corresponding service provider that lies in the vicinity of the identified base station 20-23. If the service provider's locations 30-33 have telephones, each record 302 further has an entry 305 containing the telephone number of the corresponding location's telephone.
FIG. 4 shows the interactions of elements 40-44 of FIG. 1 in providing the dealer-locator service according this invention. To access the dealer locator service, a user of a mobile telephone 40 conventionally calls the telephone number that is assigned to the dealer locator service, at step 400. The called number may be either a general number for the dealer locator service, or it may be a number for the dealer locator service of a particular one of the service providers for whom the dealer locator service is being provided. Illustratively, these numbers may be "800"-type service numbers. Alternatively, they may be telephone numbers or extension numbers of MTSO 41.
MTSO 41 receives the call generated by mobile telephone 40 at step 400 through one of the base stations 20-23, at step 402, and in response creates a call record 201 for the call in HLR 42, at step 404. As a part of step 404, MTSO 41 assigns a unique call ID to the call. If the called number is not for the dealer locator service, as determined at step 406, MTSO 41 handles the call conventionally, at step 408. If it is determined at step 408 that the called number is for the dealer locator service, MTSO 41 connects the call to IP 43, at step 410. As part of that connection, MTSO 41 passes the call ID to IP 43. IP 43 receives the call and the call ID, at step 412, and in response sends a request to HLR 42 for the call's record 201, at step 414. The request identifies the call by the call ID. HLR 42 receives the request, at step 416, and in response retrieves and returns the call's record 201 to IP 43, at step 418. IP 43 receives the call record 201, at step 420, and checks entry 203 thereof to determine if the called number is of the generic dealer-locator service or if it identifies a specific service provider, at step 422. If the called number is the generic dealer-locator service number, IP 41 generates a query to the caller via the existing call requesting the caller to identify the desired service provider, at step 424. Illustratively, the query is a recorded announcement that is played by IP 43, and the expected response is either a touch-tone signal selecting an item from a menu, or a spoken name of the desired service provider (e.g., "ATM machine", "Luigi's pizza", "service station", etc.) The caller receives the query, at step 426, and in response provides the requisite response, at step 428, which is received by IP 43, at step 430. In response to step 430, or if it was determined at steps 422-423 that the called number is for a specific service provider, IP 43 sends a query to DB 44, at step 432. This query contains a service provider ID, and the base station ID from the call record 201. DB 44 receives the query, at step 434. It uses the service provider ID to select a corresponding one of the databases 300-301, and uses the base station ID to select a corresponding record 302 from the selected database. If there is more than one record 302 for the base station ID, DB 44 selects one of them according to some desired selection criteria. For example, the selection could be random. Alternatively, the selection may be done on a round-robin basis for sequential calls. Furthermore, if the identified base station uses multiple directional antennas to serve different sectors of its cell (e.g., a CDMA system), the selection may be based on which of the antennas is serving the call. DB 44 then returns the selected record 302 to IP 43, at step 436. IP 43 receives the record 302, at step 438, and reports the contents of that record's dealer location address entry 304 to the caller, at step 440. Illustratively, IP 43 voices the record contents to the caller via conventional text-to-speech conversion. Alternatively, record 302 may contain a recorded speech file, in which case IP 43 merely plays back record 302 to the caller. The caller receives this information, at step 442, and becomes informed thereby of a geographically-proximate location of the desired service provider.
IP 43 also checks entry 305 of the received record 302 to determine if it contains a telephone number, at step 443. If not, its job is done, and so IP 43 causes MTSO 41 to end the call with the caller, at step 444. If the received record 302 contains a phone number in entry 305, IP 43 queries the caller for whether the caller desires to have that number called, at step 446. The caller receives the query, at step 448, and returns a response indicating his or her desire, at step 450. IP 43 receives the response, at step 452, and determines therefrom the caller's desire, at step 454. If the caller does not desire to have the service provider called, IP 43 causes MTSO 41 to end the call with the caller, at step 456. If the caller desires to have the service provider called, IP 43 provides the service provider's number to MTSO 41 and requests MTSO 41 to extend the call to that number, at step 458. MTSO 41 receives the request, at step 460, and in response effects a transfer of the call in a conventional manner, at step 462.
Databases 300-301 of dealer locator database 44 may be populated with data in any desired manner. One such manner is shown in FIG. 6. An administrator of DB 44 takes a mobile telephone 40 to a location 30-33 or 50-52 of the service provider whose database 300-301 is being administered, at step 600. The administrator then calls from that location a telephone number that is assigned for administration of the subject database 300-301, and the call is connected through one of the base stations 20-24 and MTSO 41 to IP 43, in the manner shown at steps 400-422 of FIG. 4 and described above. At step 423, IP 43 recognizes the called number as indicating administration of the subject database 300-301, and in response proceeds to step 602 of FIG. 6. At step 602, IP 43 queries the caller for authorization (e.g., a password) to program the subject database 300-301. The administrator receives the query, at step 604, and responds with an authorization code, at step 606. IP 43 receives the authorization code, at step 608, and checks whether it is a valid authorization for administering the subject database 300-301, at step 610. If the authorization is not valid, IP 43 ends the call, at step 612. If the authorization is valid, IP 43 queries the administrator for the address of the location from which the administrator is calling, at step 614. The administrator receives the query, at step 616, and in response speaks the address, at step 618. Alternatively, if mobile telephone 40 is equipped with a keyboard and a modem, the administrator types in the address on the keyboard. IP 43 receives and stores the address, at step 620, and then queries the administrator for a phone number of the service provider's location, at step 622. The administrator receives the query, at step 624, and responds with either the location's phone number or an indication that there is no corresponding phone number, at step 626. The administrator then moves on to a next location of the service provider, returning to step 600 to repeat the above-described process.
IP 43 receives and stores the administrator's response, at step 628. IP 43 then sends an administration command to DB 44 accompanied by the ID of the service provider whose database 300-301 is being administered, the ID of the base station 20-24, through which the call from the administrator was received (this ID was obtained at steps 414-420 of FIG. 4), the location address that was obtained at step 620, and any corresponding telephone number that was obtained at step 628, at step 630. DB 44 receives the command and accompanying data, at step 632, and in response creates therefrom a database record 302 and stores it in the one database 300-301 that is being administered, at step 634.
Of course, various changes and modifications to the illustrative embodiment described above will be apparent to those skilled in the art. For example, a different mobile communications terminal, such as a portable computer equipped with a wireless modem, for example, may be used instead of a mobile telephone. Such changes and modifications can be made without departing from the spirit and the scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the following claims.
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A dealer-locator service is provided to mobile telephones (40) in a mobile telecommunications system (FIG. 1). When a mobile telephone initiates a call to the dealer-locator service, a mobile telephone switching office (MTSO 41) identifies the one of a plurality of base stations (20-23) through which the call is made. A dealer-locator service apparatus (43-45) then uses this base-station identification, rather than the telephone number of the calling mobile telephone, to look up in a dealer-locator database (300-301) the one of a plurality of business locations (30-33, 50-52) of the dealer that is in the vicinity of the identified base station, and hence in the vicinity of the calling mobile telephone. The apparatus then reports the address of the one business location to the caller, and optionally also causes the MTSO to connect the call to a telephone number of the one business location. The dealer-locator database may be programmed by individually calling the dealer-locator service from each dealer business location via a mobile telephone that is positioned at that dealer business location and supplying that location's address and phone number. The apparatus records the identity of the base station through which the call was made along with the supplied information in the database.
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TECHNICAL FIELD
The invention relates to a portable light for producing illumination of variable intensity, and more specifically, for use with cameras to illuminate a scene for photographing.
BACKGROUND OF THE INVENTION
Portable video and film camera lights are generally common. Typically, these lights use a halogen cycle incandescent lamp in an efficient parabolic or elliptical reflector, and are powered by a belt mounted rechargeable battery pack. Early versions of portable lamps used quartz iodine lamps in the 100 W to 150 W power range and ran at a nominal color temperature of 3200° K. Power packs employing rechargeable secondary batteries such as lead-acid, sealed lead calcium or even nickel cadmium cells become unmanageably heavy and awkward if they are designed power 100 Watt lamps for any reasonable length of time. The relatively high levels of illumination developed by these high powered lamps was dictated primarily by the motion picture cameras and color film which were available at the time. Modern video cameras utilizing charge coupled devices or MOS sensors have excellent low light sensitivity and can produce acceptable images at light levels below 10 lux. The requirement for high power video lighting is therefore disappearing and instead only modest auxiliary lighting is needed for most indoor video taping. Furthermore, in most home video situations, distances of only several meters are involved so that lower power lamps are usually adequate. Experience has indicated that 25 Watt high brightness halogen lamps produce enough light for many "close in" taping situations, and are only inadequate at relatively great distances or at very close range, where they can wash out the image highlights due excessive brightness. High brightness video lamps running at high temperature generally last very few hours.
The range of illumination encountered in indoor close up taping and outdoor fill situations is very great. In many applications of auxiliary lighting the dynamic lighting control range of the typical video camera is inadequate. Even though camera lens iris control and image sensor gain can be adjusted, often it is more expedient to control the illumination level by adjustment of the off camera lighting equipment.
There are light responsive devices for controlling various types of lamps, but none are portable and to be used with cameras. One light responsive device is utilized with a control panel, such as on a vehicle. The panel control includes an ambient light sensor, wherein constant contrast illumination control is achieved by pulse width modulation. As the sensor sensing greater ambient light, the pulse widths increase to provide greater illumination. Such a device is disclosed in U.S. Pat. No. 4,368,406 issued Jan. 11, 1983 in the name of Kruzich et al.
A second type of light responsive control is disclosed in U.S. Pat. No. 4,464,606 issued Aug. 7, 1984 in the name of Kane and U.S. Pat. No. 4,682,084 issued July 21, 1987 in the name of Kuhnel et al. Both systems are self-adjusting ballasts for fluorescent lamps. A light sensor maintains the lamps at a predetermined brightness level.
None of the prior art systems disclose a battery powered, portable light for use with cameras which automatically varies lamp output. None of these prior art devices could be used as a portable video lamp.
SUMMARY OF THE INVENTION AND ADVANTAGES
The invention is a portable light assembly adapted to be connected to a camera and directed toward the scene. The assembly comprises portable housing means adapted to be connected to a camera. The housing means includes battery power means supported by the housing means for supplying d.c. power, radiant means supported by the housing means and connected to the battery power means for producing radiant energy to illuminate a scene, and control means connected between the battery power means and the radiant means for receiving a control signal and for switching power to the radiant means controlling the intensity of illumination by the radiant means. The control means includes sensor means for sensing ambient light and reflected radiant energy from the scene indicative of brightness of the scene and for producing the control signal, and switching means responsive to the control signal for switching power to the radiant means controlling the brightness. The switching means including a field-transistor for switching high current to said radiant means.
The invention also includes control means connected to the power supply means and the radiant means for receiving a control signal comprised of pulses and for switching power to the radiant means controlling the intensity of the illumination by said radiant means. The control means includes sensor means for sensing ambient light and reflected radiant energy from the scene indicative of brightness of the scene, modulator means connected to and responsive to the sensed brightness by the sensor means for producing a control signal and for controlling the width of the pulses to control the average intensity of illumination by said radiant means, and switching means in series with the power means and the radiant means for receiving the control signal and for switching the power to the radiant means for a time proportional to the width of the pulses.
The invention also provides a radiant means which includes a first filament means for producing a predetermined intensity of illumination and a second filament means for producing a variable of intensity of illumination and control means connected to the power supply means and the second filament means for switching power to the second filament means to automatically control the intensity of illumination produced by the second filament means.
The invention provides a portable, battery powered video light which is automatically controlled to provide optical illumination levels in a variety of situations while it conserves battery power. Furthermore, the use of two filaments maintains proper color balance.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
FIG. 1 is a perspective view of the subject invention;
FIG. 2 is a schematic diagram of the first embodiment of the subject invention;
FIG. 3 is the more specific schematic diagram of the first embodiment; and
FIG. 4 is a schematic diagram of the second embodiment of the subject invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A portable light assembly for use with a camera 12 is generally indicated at 10 in FIG. 1. The light assembly 10 illuminates a scene 14 which is being photographed by the camera 12. The assembly 10 includes power supply means 16 for supplying power to allow the assembly 10 to become portable. The power supply means 16 may be a nickel-cadmium or sealed lead-acid rechargeable battery pack. The battery pack 16 includes a charger/adapter 18 for connection to an external power source, such as a 120 V. ac outlet, as is commonly known. The assembly 10 is ease of maneuvering with the camera 12 or attachment therewith. The battery 16 may be enclosed in the housing 19 or individually portable, i.e., to be separately carried by the photographer with a power line to the assembly 10.
The assembly 10 includes radiant means 20 connected to the battery 16 for producing radiant energy to illuminate the scene 14. The radiant means 20 is generally a halogen incandescent lamp. By using a high brightness, medium power, halogen incandescent lamp 20, the assembly 10 can automatically adjust its average output power to maintain essentially constant illumination of a scene or subject 14, irrespective of scene 14 reflectivity or distance from the illuminating lamp 20. At relatively farther distances, the lamp 20 runs "wide open" and operates at its maximum rated output, typically 25-50 Watts. At closer distances to the scene or subject 14, the assembly 10 reduces lamp 20 brightness to compensate for its proximity or to compensate for high ambient light levels. The assembly 10 will also compensate for changing scene 14 brightness due to changes in reflectivity of the subject 14. Alternatively, the radiant means 20 may comprise a fluorescent lamp. The lamp 20 includes a reflector 22 to direct all of the radiant output of the lamp 20 toward the scene 14.
The assembly 10 includes control means 24 connected to the power supply 16 and the radiant means 20 for receiving a control signal comprised of pulses and switching power to the radiant means 20 to control the intensity of illumination by said radiant means 20. More specifically, the lamp 20 has a first lead wire 26 connected to the positive terminal 28 of the battery 16 and a second lead wire 30 connected through the control means 24 to the ground terminal 32. The control means 24 connects and disconnects the second lead wire 32 to ground 34 to supply power to the lamp 20 when connected to control the intensity of illumination. Since only the time current through a lamp 20 filament determines the temperature, it is possible to control the output of lamps 20 with variable duty cycle dc pulses.
The control means 24 includes sensor means 36 for sensing ambient light and reflected radiant energy from the scene 14 indicative of brightness of the scene 14, which acts as feedback to the assembly 10. The sensor means 36 is a photo sensor. The photo sensor 36 is either photo voltaic or photo resistive to increase or decrease voltage or resistance proportional to the amount of light impinging thereon. Generally included is a collimator 38 for limiting the field of view of light sensed by the photo sensor 36. The collimator 38 directs the sensitivity of the photo sensor in the direction of the lamp 20 in order to sense the brightness of the scene 14.
The camera 12 photographs a scene 14 of limited cross-sectional view, dependent on distance. Therefore, it is important that the photo sensor 36 only receive light energy from the same general direction at which the camera 12 is directed. The collimator 38 ensures that light is received from only the scene 14 at which the camera 12 is directed.
The control means 24 includes modulator means 40 responsive to the sensed brightness by the sensor means 36 for producing the control signal and for controlling the width of the pulses to control the intensity of illumination by the radiant means 20. The modulator means 40 is generally a pulse width modulator, as commonly known in the art. The pulse width modulator 40 may include a 555 integrated circuit timer chip configured as a pulse width modulator 40. The pulse width modulator 40 running in excess of the lamp 20 flicker rate, typically 100-500 Hz, is preset by the user or manufacturer to some nominal level to yield a given pulse width ON time for a given scene brightness.
The modulator means 40 includes timing means 42 responsive to the sensor means 36 for producing a timing signal indicative of a time period inversely proportional to brightness, and pulsing means 44 for receiving the timing signal to produce the control signal having pulse width proportional to the time period. The timing means 42 is connected to the photo sensor 36 and produces the timing signal representative of the time period of charging a capacitor C1. The pulsing means 44 comprises the 555 timer chip. The timer means 42 receives power through resistor R1 and to a forward biased diode D1 and reversed biased diode D2. The forward biased diode D1 is connected to the photo sensor 36 (resistive) to capacitor C1 to ground. The reverse biased diode D2 is connected though resistor R2 to the capacitor C1. The capacitor C1 is connected to input pins 2 and 6 of the 555 timer 44, and resistor R1 is connected to pin 7. The timer 44 is powered at pins 4 and 8 and grounded at pin 1 and through capacitor C2 to pin 5. The output pin 3 produces the control signal through a low pass filter comprising resistor R3 and capacitor C3.
The control means 24 further includes switching means 46 in series with the battery 16 and the light 20 for receiving the control signal and for switching power to the radiant means 20 for a time proportional to the width of the pulses. The switching means 46 comprises a field-effect transistor (FET). The advent of reasonably price MOSFET devices which can switch tens of Amperes at relatively high speed permit efficient pulse width control of low voltage, high current loads. Bipolar transistors which were previously available suffer from high drive current requirement and high dissipation loss due to typical Vce levels of 0.7 volts. A bipolar transistor or other transistors may also be utilized.
The lamp 20 is driven by the MOSFET power switch 46 which receives continuous power from the dc source 16. The gate of the FET switch 46 receives the control signal and the drain is connected to the ground terminal 32 and the source is connected to the second lead wire 26 of the lamp 20. Therefore, when the FET switch 46 is switched on by a pulse, current flows through the lamp 20 where upon turning off the switch 46, current is prevented from flowing through the lamp 20.
The pulse width modulator 40 yields the given pulse width ON time for a given scene brightness. The photo sensor 36 then either increases or decrease this ON time pulse width in response to the sensed scene 14 brightness. Pulse width modulation control of a lamp 20 not only greatly extends battery 16 operating time, but increases lamp 20 life by reducing the length of time that the filament has to run at extremely high temperatures. Extended operation at lower power levels, which is unlikely in typical consumer video camera use, does present some problems, however. Halogen cycle incandescent lamps depend on a minimum bulb wall temperature of about 200 degrees C. in order to vaporize the tungsten halide (bromide or iodide) and prevent deposition on the envelope. Some darkening of the bulb would result from extended low temperature operation as the tungsten halide (bromide or iodide) collect on the relatively cool bulb wall. This effect is temporary as momentary operation at an elevated temperature would again volatilize these deposits. Electronic limits could be established to prevent bulb operation at high ambient light levels to prevent extended low wattage use.
The assembly 10 includes a control indicator 48 which is useful to inform the user that the scene brightness is within the servo control range. Either monitoring the pulse width modulator 40 using a window comparator to supervise the photo detector 36 is adequate.
The assembly 10 further includes charge monitor means 50 for monitoring the charge on the battery 16 and for visually indicating the time remaining on the charge. The monitor 50 informs the user of the time remaining on a given charge, so that recharging can be planned at a convenient time.
The control means 24 includes a preset switch 49 for establishing the desired brightness of the scene 14. The control signal is compared to this preset level to determine any change in present pulse width output. If the control signal indicates greater brightness than the present level, the pulse width is decreased, and vice versa.
A further problem is presented that in critical taping were color rendition is important, maintaining proper color balance is difficult when the color of the illuminating light is changing. In other words, as the color balance of the illuminator 20 shifts due to changes in power level (filament temperature) the scene 14 becomes "warmer" or "cooler". Camera image sensors 12 do not adapt as the human eye to color shift, even with the automatic white balance feature of most cameras 12. The white balance control usually electronically corrects for non-optimal color temperatures by monitoring a "white" level in the image 14. Assuming the object should be truly white, the camera 14 then adjusts the primary color gain levels to yield an acceptable "white" output signal applying the same correction to all other elements. Should the white subject change position, reflectivity or disappear, color balance is drastically effected. Under constant color illumination, most cameras 12 actually yield better results with fixed daylight or tungsten settings. Under those conditions, it is imperative that the color temperature of the illumination remain reasonably constant making variable light output incandescent lamps unsuitable for critical work.
The second embodiment of the assembly 10' addresses these color problems and is generally illustrated in FIG. 4. Common components as in the first embodiment 10 are indicated by like numbers primed. The second embodiment 10' utilizes the same portable housing 19 directed at the scene 14, as illustrated in FIG. 1. The radiant means 20' includes first filament means 52 for producing a first intensity of illumination and second filament means 54 for producing a second intensity of illumination. Instead of continuously varying the output power of the single filament lamp 20 and accepting the decrease in color temperature as the lamp 20 is dimmed, a single bulb 20' with two filaments 52, 54 is used. By operating each filament 52, 54 at a fixed power level, the illumination color balance remains constant, and the luminous efficiency of the lamp 20' remains high. The assembly 10 must now correct for greater changes in scene 14' illumination due to the step-wise transition from one filament 52 to two 54. Using one dual filament bulb 20' in a single reflector 22' and socket assembly saves cost, weight and space.
The control means 24', 24" is connected to the power supply means 16' and the first 52 and second 54 filaments for switching power to the filament 52,54 to automatically control the intensity of illumination. The assembly 10' includes sensor means 36' for sensing ambient light and reflected radiant energy from the scene 14. Included are first 46' and second 46" switching means connected to the first 52 and second 54 filaments, respectively, each in series with the battery 16' and the filaments 52, 54. The control means 24', 24" includes a first controller 24' and a second controller 24" for receiving the control signal and connected to the first 52 and second 54 filaments, respectively. The switching means 46', 46" are MOSFETs. The controllers 24', 24" may be of the modulated type described with respect to the first embodiment 10, or may allow the filament 52, 54 to operate at its rated output (a single predetermined level).
In a first dual filament embodiment, the second controller 24" is of the same type as the control means 24 described with respect to the single filament of first embodiment 10. The first controller 24' is connected to the battery 16' and the first filament 52 for switching power continuously to the first filament 52 to establish a predetermined intensity. The second controller 24" and switch 46" operate at a variable rate dependent on the control signal. For example, if high light level is sensed, it may be necessary to only operate the first filament 52 and not the second filament 54. If low light is sensed, the first filament 52 is continuously operated between ON and OFF and the second filament output 54 is variably operated to accomplish a predetermined brightness level as sensed by the sensor 36'. In other words, the controllers 24', 24" may include a comparator such that three levels are established. For example, if the output of the sensor 36' is below a first level, the first filament 52 will turn on; if the output is between the first and second level, the second filament 54 will turn on, and if the output is above the second level, both filaments 52, 54 will turn on.
A second embodiment includes controllers 24', 24" operating the first filament 52 and second filament 54 at individual predetermined intensities. Generally, the first filament will be continuously switched on at its rated output, and the second filament 54 will be switched on and off dependent upon the sensor 36' and amount of light required. There may be three levels of illumination produced by the light: A low level produced only by the first filament 52, an intermediate level produced only by the second filament 54 and a high level produced by both the first 52 and second filament 54. It is to be understood that the controllers 24', 24" may be any combination of the fixed regulated intensities or the variable modulated intensities.
The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.
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An automatic battery powered video light (10) is supplied power by a d.c. battery (16). A light (20) is connected between a first terminal of the battery (16) and a MOSFET switch (46), which is connected to a second terminal of the battery (16). A control circuit (24) controls the opening and closing of the MOSFET (46) to supply power to the light (20) and disconnect power from the light (20). The control circuit (24) includes a light sensor (36) for sensing ambient light and reflected radiant light from a scene (14) and a pulse width modulator (40) for controlling the MOSFET switch (46). The modulator (40) increases pulse width and therefore closing time of the switch (46) when the sensor (36) senses time low light levels, and vice versa. Also provided is a dual filament light (20') wherein each filament (52, 54) is independently controlled to enhance color balance.
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This is a division of application Ser. No. 07/045,557, filed May 4, 1987, now U.S. Pat. No. 4,927,429, issued May 11, 1992.
BACKGROUND OF THE INVENTION
This invention relates to a process for dyeing synthetic fabrics using high-boiling ester solvent media in which a dye or mixture of dyes meeting selected performance and physical criteria is used.
Synthetic fabrics can be dyed rapidly and effectively at elevated temperatures using dyes dissolved in and applied from high-boiling ester-type solvents. Waterless dye compositions for apparel and other thermoplastic articles are described in a series of U.S. patents to Robert B. Wilson, more fully identified below, and exemplified by U.S. Pat. No. 4,581,035. See also U.S. Pat. No. 4,550,579 to Clifford which proposes using the same ester materials in a non-reactive, inert atmosphere.
The Wilson-type waterless dyeing compositions are said to include the use of various dyes or pigments as organic colorants in these waterless dye compositions. A wide variety of candidate dyes and pigments are identified in column 8 of this patent, as well as in column 13, lines 31-35 of the Clifford patent. These documents indicate that the choices of suitable dyes and pigments are extremely wide, and that results using any particular dye or pigment selected are comparable, one to the other. It has now been found that only a limited number of dyes meeting very stringent and diverse criteria are actually suitable and form a preferred class for dyeing synthetic fibers, notably nylons and polyesters.
The process of the present invention in one aspect features the use of solvent dyes dissolved in high-boiling ester solvents to color synthetic textiles, notably polyester and nylon. Relatively few dyes are soluble in these high-boiling organic ester materials. The common practice in the art has been to use a class of water-insoluble dyes known as disperse dyes, that is, dyes that are only dispersible rather than soluble in water. These dyes are the type exemplified in the Wilson patent noted above.
SUMMARY OF THE INVENTION
Described is a process for dyeing synthetic textile fibers by dyeing them at elevated temperatures in a waterless coloring composition composed of a high-boiling ester solvent and a specifically selected dye. The dye or mixture of dyes used must meet the following criteria: (1) The dye must be soluble in the high-boiling solvent at 350° F. to the extent of at least 1.5% by weight based on the weight of the solvent, (2) the dye must provide a yield, calculated as the quotient of the integrated depth value of a sample dyed in the ester solvent divided by the integrated depth value of a sample dyed in an aqueous dyeing system with the same weight of a proven disperse dye of the same or substantially the same color, expressed as % yield, of at least 25%, (3) the dye must exhibit on a fabric a lightfastness value, according to AATCC Test Method 16A-1982 for 40 hours of exposure, of at least 3, and (4) the dye must provide a washfastness value of at least 3 according to AATCC Test Method 61-1985-IA.
Other features of the invention will be apparent from the detailed description that follows.
DETAILED DESCRIPTION OF THE INVENTION
Before discussing details of the process of this invention, it is important to carefully define the terms as used in the following disclosure, specification and claims, and as generally used in the dyeing art in which perhaps the preeminent text is The Colour Index. The Colour Index refers to dye classes, such as acid dyes, basic dyes, disperse dyes, solvent dyes, etc., as usage classes. Specific usage names such as C.I. Solvent Yellow 77 are formally called C.I. Generic Names; less formally, use or usage names. The "generic" derives from the multiple manufacturers' specific tradenames for the same dye. The 5-digit number accompanying the dye when its structure is known--C.I. 11855 for the above yellow dye--is its "C.I. Constitution Number".
There are distinct differences between disperse dyes and the solvent dyes used in the process of this invention. The terms "disperse dye" and "solvent dye" are "use" terms, and both of them encompass dyes containing very similar chemical groupings. The chemistry of the dyes, therefore, offers no general promise for distinguishing between the two use classes.
Historically, the name "disperse dyes" reflects the fact that they are mostly used as slightly soluble dispersions in aqueous media. A "solvent dye", on the other hand, is intended for use in a non-aqueous organic solvent. In the context of the present invention, the general difference between disperse dyes and solvent dyes is that in the dyeings in high-boiling hydrophobic solvents, the solvent dyes are more soluble, resulting in greater color yields in many but not all instances, a greater margin of protection against a need for excessive heating to put them in solution, and more capacity for avoiding dye precipitation if the dye solution inadvertently cools while being used. All of these are significant engineering advantages.
Disperse dyes are not sold simply as the powder or solid themselves; rather, they are formulated and designed for use in an aqueous medium. A commercial disperse dyestuff, designed for use in an aqueous medium, is made by washing the solid presscake from the dye synthesis thoroughly with water and then, since the dye itself is virtually insoluble in water, mixing it with a sizable amount of dispersing agent and other additives, if desired. The exact amount of dispersant and additives is varied, depending on the analysis of colorant in each batch, as the way of assuring equal amounts of dye, and thereby color uniformity, from lot to lot. The presscake, whether wet or dried, is known loosely in the art as the "crude" dye; it does not really become a disperse dyestuff until it is mixed with dispersant. This dispersant typically constitutes 60-80% of the weight of commercial disperse dyestuffs, and is anionic in nature.
To determine potentially suitable dyes from the large number of candidates available, a simple solubility screening test was conducted. In this test, an excess weight of the candidate dye was slurried in tris(2-ethylhexyl) trimellitate at 350° F., the mixture filtered rapidly, the weight of the dye caught on the filter recorded, and the percentage of dye dissolved in the hot solvent, based on the weight of the solvent, calculated. Further details of this test are given below. A minimum solubility value of 1.5% is required to pass this initial test.
Given their high content of anionic water soluble dispersants, commercial disperse dyes cannot be more than fractionally soluble in hydrophobic solvents such as tris(2-ethylhexyl) trimellitate. Unlike their good dispersions in aqueous media, the commercial disperse dyes tend to produce tarry, gummy precipitates in many organic solvents.
There are two essential aspects of the invention, both dealing with the use class of the dyes employed, and more specifically with subdivisions of the solvent dye class. One is the use of nonionic solvent dyes, and the other the use of premetallized solvent dyes.
The high-boiling ester solvent used in the process of this invention is an organic composition that remains stable within the temperature range of from about 50° F. to about 450° F. Such high-boiling organic solvents are described in the patent literature and elsewhere as vehicles or solvents for dyestuffs and pigments to form waterless dyeing compositions. See, for example, U.S. Pat. No. 4,293,305 to Wilson.
The aromatic esters can be of the formula ArCOOR 2 , ArCOO-R 1 -OOCAr or (ArCOO) 2 --R 3 , wherein R 1 is alkylene of 2-8 carbon atoms or polyoxyalkylene of the formula (--C r H 2r ) s --, in which r is 2 or 3 and s is up to 15; R 2 is substituted or unsubstituted alkyl or alkenyl of 8-30 atoms; R 3 is the residue of a polyhydric alcohol having z hydroxyl groups; Ar is mono- or bicyclic aryl of up to 15 carbon atoms and z is 3-6.
Furthermore, the cycloaliphatic ester can be of the formula: ##STR1## wherein R is substituted or unsubstituted straight or branched chain alkyl of 4-20 carbon atoms, polyoxyalkylene of the formula R'(OC x H 2x ) n or phosphated polyoxyalkylene of the formula:
(HO).sub.2 P(═O)(OC.sub.x H.sub.2xn OC.sub.x OC.sub.x H.sub.2x)
or a salt thereof, wherein (OC x H 2x O) n is C 2 H 4 O) n --,(C 3 H 6 O) n --or (C 2 H 4 O) p , or (C 3 H 6 O) q --; R 1 is H or ArCO; Ar is mono- or bicyclic aryl of up to 15 carbon atoms; x is 2 or 3; n is 2-22 and the sum of p+q is n.
The preferred high-boiling organic solvents include triesters of 1,2,4-benzenetricarboxylic acid, also known as trimellitic acid. Preferred esters are tris(2-ethylhexyl) trimellitate, triisodecyl trimellitate, triisooctyl trimellitate, tridecyl trimellitate, and trihexadecyl trimellitate. It will be understood that mixed esters such as hexyl, octyl, decyl trimellitate can also be used. Most preferred is tris(2-ethylhexyl) trimellitate (CAS No. 3319-31-1), also known as trioctyl trimellitate, which can be purchased from Eastman Chemical Products, Inc., Kingsport, Tenn., as Kodaflex® TOTM.
Other high-boiling, nonionic ester solvents suitable for this invention include, among others, those described in U.S. Pat. Nos. 4,293,305; 4,394,126; 4,426,297; 4,581,035; 4,602,916; 4,608,056; and 4,609,375. The preparation of the materials described above is given in U.S. Pat. No. 4,529,405, the disclosure of which is herein incorporated by reference.
TESTS FOR DETERMINING SUCCESSFUL DYES OF THE INVENTION
With both the premetallized and nonionic solvent dyes, the determination of success, hence suitability for the process of this invention, versus failure has been based on four measured and apparently distinctive parameters. These are solubility, yield, lightfastness, and wetfastness. Each feature is explained and quantified in detail below. A major difference between the process of this invention and the teaching of the prior art is that the former clearly recognizes the selectivity of a very limited number of solvent dyes particularly suited for dyeing nylon and polyester; while the latter, in the apparent absence of measurements of any of the four parameters above, suggests that virtually any dye would be successful. The four parameters selected distinguish the carefully selected dyes used in the process of this invention from the dyes generally suggested for use in high-boiling solvents. The parameters selected are consistent with the practical aspects of the art of dyeing. As a practical matter, it makes a great deal of difference whether a coloration represents only the staining of a given fiber rather than a dyeing controllable in depth of color depending on dye concentration, dyeing time, and temperature. Applicant has determined that only a small fraction of even the solvent dyes tested succeed in passing the enumerated tests, which is to say that they show promise of practical utility when employed in high-temperature dyeings in the high-boiling ester media.
Dyes suitable for use in the process of this invention are selected from the wide variety of candidate dyes available based upon a combination of four parameters: solubility of the dye in the solvent medium (for test purposes solubility was assessed in tris(2-ethylhexyl) trimellitate at 350° F.), dyeing yield, lightfastness, and washfastness.
These physical parameters are defined in detail as follows:
Solubility--The solubility of solvent dyes by weight in tris(2-ethylhexyl) trimellitate at 350° F. was determined by slurrying an excess weight T in grams of each dye in 250 g of the hot solvent, filtering the mixture rapidly through a fiberglass filter, and recording the dye caught on the filter. To facilitate testing procedures, in view of the large number of dyes tested, a tare correction was made to allow for solvent retained on the wet dye and to give the dry insolubles weight F. The percentage solubility, based on the solvent weight, was calculated for each dye using the formula: ##EQU1##
The solubilities of the nonionic solvent dyes ranged from 2.0 to 4.0 percent; the premetallized solvent dyes that were soluble enough to perform in the process of the invention, from 1.5 to 3.0 percent. Both effective and ineffective dyes of both types fell within these ranges, so that determining only the solubilities of the dyes does not, by itself, form a reliable basis for separating the suitable from the unsuitable dyes.
The lower limit of solubility for dyes suited for use in the process of this invention has been set at 1.5% in tris(2-ethylhexyl) trimellitate on the basis that a lower solubility at dyeing temperature would itself lower the color and the dyeing rate too far to yield practical dyeings.
Yield--The yield, an expression of comparative depth of coloration as defined in the invention is a relative and practical value. It represents a comparison of what can be done in solvent dyeings of the invention with what can be achieved with conventional aqueous dyeings of the same substrate fabric. The basic idea behind this parameter is the practical fact that there is no incentive to resort to the generally more costly solvent dyeing if the depth of coloration it gives is so much less than what can be achieved with less costly aqueous dyeing as to offset the advantages of speed and other merits of the solvent dyeings achieved by the process of this invention.
The percentage color yield for each solvent dye is sometimes expressed in terms of the calculated KSSUM values for the solvent dyeings and the corresponding aqueous disperse dyeings; or ##EQU2##
The term "KSSUM" is also known as the integrated depth value as described by Besnoy, Textile Chemist and Colorist, Vol. 14, No. 5, page 34 (1982), a term which applicants have adopted for their purposes in the present invention. See also the article by Kuehni (Textile Chemist and Colorist, Vol. 10, NO. 4, page 25 (1978).
As used herein, the percent yield is expressed as: ##EQU3##
Lightfastness--The lightfastness values cited for the solvent dyes of the invention were determined by AATCC Test Method 16A-1982, "Colorfastness to Light: Carbon-Arc Lamp, Continuous Light". The exposure times were 40 hours and 200 hours.
For evaluation of the results the extent of fading of each test specimen was judged by visual comparison with the Gray Scale, in which a 5 rating means no fading, as described in the AATCC Technical Manual/1986 AATCC Evaluation Procedure 1, "Gray Scale for Color Change". In order to meet minimum acceptance standards, a minimum Gray Scale acceptance rating of 3 after 40 hours has been set for the dyes suited for use in the process of this invention, but it will be noted that nearly all of the preferred premetallized dyes of the invention significantly exceeded this minimum rating even after 200 hours.
Washfastness--The washfastness values cited for the solvent dyes used in the process of the invention were determined by AATCC Test Method 61-1985-IA, "Colorfastness to Washing, Domestic; and Laundering, Commercial: Accelerated". The color loss in these 45-minute tests is designed to equal that resulting from five average hand, commercial, or home launderings. Here too the Gray Scale changes, above, are the basis for the cited ratings. The minimum acceptance rating for this test was set at 3-4.
Of these four parameters, lightfastness and washfastness are among the quality measurements of dyeing. Proper dye solubility determines whether enough dye will be present in solution around the fiber to provide for rapid diffusion into it, yet not be so soluble as to keep the dye in solution. Yield is a measure of which dyes diffuse into which fibers, and how much. The premetallized solvent dyes worked only on nylon, not polyester, for example.
Table 1 shows that out of the 65 nonionic solvent dyes tested, only four of known formula (having a C.I. Constitution Number) passed the above tests, with either nylon 66 or polyester, but only in one instance with both fibers. In addition to these chemically identifiable nonionic solvent dyes, seven more, having no C.I. Constitution Number, passed the tests of the invention: C.I. Solvent Yellow 93; C.I. Solvent Yellow 114; C.I. Solvent Orange 47; C.I. solvent Orange 60; C.I. Solvent Red 194; C.I. Solvent Violet 31; and C.I. Solvent Blue 59. Once again only one of these seven, C.I. Solvent Yellow 93, was successful with both nylon and polyester.
TABLE 1__________________________________________________________________________Dyeings of Nylon and Polyethylene TerephthalateWith Nonionic Solvent Dyes AATCC Light-C.I. Identity fastness Rating AATCC Wash-Use Name Constitution No. Fabric Solubility Yield 40 hrs. 200 hrs. fastness Rating__________________________________________________________________________Solvent Yellow 77 11855 nylon 3.5 65 4 2 5Solvent Red 52 68210 PET 4 100 4 1 4-5 nylon 4 80 3-4 1 4-5Solvent Red 111 60505 PET 3.5 60 3-4 1 4-5Solvent Violet 13 60725 PET 3 80 4 1 4-5Solvent Yellow 93 PET 4 100 5 2 5 nylon 4 90 4-5 1 4-5Solvent Yellow 114 PET 4 100 5 2 4-5Solvent Orange 47 nylon 4 100 5 1 5Solvent Orange 60 PET 3.5 100 4 1 4-5Solvent Red 194 PET 2 80 4-5 1 5Solvent Violet 31 PET 2.5 80 4 1 5Solvent Blue 59 nylon 2.8 80 5 1 4-5__________________________________________________________________________
TABLE 2__________________________________________________________________________Dyeings of Nylon With Premetallized Solvent Dyes AATCC Light-C.I. Identity Solubility Yield fastness Rating AATCC Wash-Use Name Constitution No. % % 40 Hrs. 200 Hrs. fastness Rating__________________________________________________________________________Solvent Yellow 21 18690 1.9 50 5 4-5 4Solvent Orange 45 11700 2.1 80 5 5 3-4Solvent Red 8 12715 1.75 55 5 3 3-4Solvent Red 102 15675 1.5 50 5 4 3-4Solvent Blue 55 74400 1.5 45 3 1 4Solvent Black 35 12195 2 85 5 4 5Solvent Yellow 83:1 3 100 5 4 4-5Solvent Orange 54 2 90 5 4-5 4-5Solvent Red 22 2.75 100 5 5 4-5Solvent Black 27 2.5 100 5 5 5Solvent Black 45 2.25 95 5 5 4__________________________________________________________________________
It will be seen from Table 1 that only two of the eleven nonionic solvent dyes gave passing results with both nylon and polyester, while three succeeded with nylon alone and six with polyester alone. The most distinctive differences between these nonionic solvent dyeings and the premetallized solvent dyeings lay in the inferior 200-hour lightfastness ratings shown in Table 1 for the nonionics, contrasted with the greatly superior behavior of the premetallized dyeings.
In Table 2 there are summarized the results of dyeing nylon with the eleven premetallized solvent dyes which satisfy the requirements of this invention, beginning with six of known chemical structure and ending with the dyes known only by their C.I. usage names.
A larger proportion of the premetallized solvent dyes than of the nonionic solvent dyes tested passed the standards for the dyes of the invention as set forth above. Even though they are effective only on nylon substrates, the premetallized solvent dyes are preferred to the nonionic solvent dyes and the reason for this is clearly shown in Table 2. The premetallized solvent dyes of the invention, with the sole exception of C.I. Solvent Blue 55, were greatly superior to the nonionic solvent dyes in the 200-hour lightfastness tests. Otherwise the performances of the dyeings with the two classes of dyes were not significantly different.
A total of 122 commercially available and standardized solvent dyes were tested, including 42 premetallized dyes and 65 nonionic dyes. The remainder of the 122 dyes were 10 basic dyes and 5 acid dyes, which 15 were not soluble enough in solvent to pass.
Out of the 42 premetallized solvent dyes tested, Table 2 shows six passing the tests whose formulas were found in The Colour Index. Besides these six dyes of known composition, five others identified only by their C.I. use names also passed: C.I. Solvent Yellow 83:1, C.I. Solvent Orange 54, C.I. Solvent Red 22, C.I. Solvent Black 27 and C.I. Solvent Black 45.
All of the lightfastness and washfastness data in Tables 1 and 2 were obtained from identical dyeings of 3×4-inch swatches of nylon 6,6 (14 ounce per square yard automotive fabric made from low tenacity staple) or of woven polyethylene terephthalate homopolymer fabric. The dyeings were carried out in one percent solutions of each dye in tris(2-ethyhexyl) trimellitate, preheated to 350° F. with the premetallized solvent dyes and 390° F. with the nonionic solvent dyes. (Dyeings of the more dyeable nylon at 350° F. with the premetallized dyes were as efficient as at 390° F., and were preferred because they afforded a larger margin of protection from thermal damage to the nylon fabric. Polyester needed the higher temperature for a high dyeing yield). Each swatch was immersed in the dyebath for one minute, then rinsed in perchlorethylene until the rinse liquor became free of color, after which the swatches were dried and portions were subjected to lightfastness and washfastness testing. The solubility and yield data in the Tables were determined as described above.
General dyeing conditions such as manner of application, operational temperatures and pressures, wet pick-up, scouring, drying and other aspects of the process are in accordance with the conventional practice in the art, and need not be described in detail in this application.
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Synthetic textile fibers are dyed in a waterless coloring composition composed of a high-boiling ester solvent and a dye that (a) is soluble to the extent of at least 1.5% in the solvent, (b) provides a depth of coloration, expressed as yield, of at least 25%, (c) imparts to the dyed fibers a lightfastness value of at least 3, and (d) provides the dyed fibers with a washfastness value of at least 3.
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RELATED APPLICATION
This application is a continuation of application Ser. No. 08/436,830 filed May 8, 1995, now U.S. Pat. No. 6,678,880, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention is directed to computers which operate with object-oriented programs, and more particularly to a system which permits the heterarchy of objects in an object-oriented computing environment, as well as the characteristics of those objects, to be dynamically designed and modified.
BACKGROUND OF THE INVENTION
Object-oriented programming of computers is gaining increasing popularity, in large part due to the great deal of flexibility which it offers with a relatively simple structure. Generally speaking, an object-oriented program comprises a collection of software entities known as objects, each of which is responsible for performing a particular task. Every object is characterized by associated properties, or data values, and one or more handlers that provide certain behavior or functionality. In operation, one object invokes the handlers of another object, to cause the second object to exhibit its associated behavior.
The behavior and properties of a given object can be extended to other objects through an inheritance structure. In such a structure, groups of associated objects can be organized in a hierarchical inheritance tree. In this type of arrangement, an object at a particular level of the hierarchy will inherit the properties and behavior of objects at higher levels from which it descends. Similarly, its property and behavior, including that inherited from higher-level objects, is passed on to lower-level objects that descend from it in the hierarchy.
The inheritance of object properties and handlers in an object-oriented program provides a number of desirable characteristics. Foremost among these is the reusability of software. Since an object at a lower level of the hierarchy inherits all of the behavior of objects at higher levels, the program code that provides particular behavior does not have to be rewritten for each object that is to exhibit that behavior. Consequently, fewer instances of that code exist in the program, and the debugging and testing of that portion of the code is therefore simplified. Another desirable aspect of inheritance is the consistency of interfaces that are provided. All objects which inherit from the same object or set of objects at a higher level of the hierarchy will exhibit the same properties and behavior, and thus present a consistent interface to the user.
Programming in an object-oriented system requires the programmer to build a structure for the set of objects, which defines how properties and handlers are to be inherited. Designing such a structure can be a complex and difficult task. Typically, the programmer doesn't begin the design of the code with the optimum structure in mind at the outset. Rather, as the program is developed, the designer typically discovers desirable variations to the original structure. For example, the designer may discover that a number of objects share a common attribute, and therefore should descend from a common parent to encapsulate that attribute. During development, the overall structure of the object-oriented program, i.e., its inheritance hierarchy, is typically modified over several iterations in such a fashion.
In the past, most program code for object-oriented systems has been text-based. More particularly, the relationships between objects in the hierarchy was described by means of a text file. From this text file, a database was built in working memory, e.g. RAM, to define the relationships during the run-time of the computer. Redesigning of the hierarchy in such systems involved changing the text scripts that defined the hierarchical relationships of the objects. These types of changes required the programmer to manually search through all of the files to find relevant portions of code and objects, and make the required changes. Typically, this was carried out by means of rather crude search and replace operations.
The redesigning of the code structure was even more complicated for object-oriented systems which support multiple inheritances. In these types of systems, an object can descend from, i.e. inherit properties and handlers from, more than one parent object at higher levels of the structure. The term “heterarchy” is used to describe the structure which exists in this type of system. A heterarchy differs from a conventional hierarchy by virtue of the fact that, in a hierarchy each object descends from one, and only one, parent object, whereas in a heterarchy each object can directly descend from more than one parent object. When an object descends from two or more parents, the parents are given a relative priority, or precedence, with respect to that object, in the event that some of their properties and/or handlers are mutually exclusive to one another. Because the interrelationships of objects in a heterarchical structure is much more complex, redesigning such a structure becomes significantly more difficult.
A particularly complex task in the redesign of the program structure is the addition and deletion of levels of the hierarchy or heterarchy. Typically, these kinds of changes involved writing new code to describe new objects in an added level or to remove references to objects in a deleted level, and then recompiling the program to incorporate the newly added code. Similarly, in the design of the program, if it became desirable to reorganize properties or handlers, for example to transfer a property from a descendant object to a newly added parent object, the associated code had to be rewritten and then recompiled.
It is desirable, therefore, to provide a system which permits a user to dynamically design and rearrange object structure, as well as design and rearrange the properties and handlers for an object after the structure has been redesigned, without the need to rewrite and recompile code.
SUMMARY OF THE INVENTION
In accordance with the present invention, this objective is achieved in an object-oriented computing environment by storing information relating to objects in a data file, and manipulating the information in the data file through a suitable user interface. The interface permits a user to completely redesign the program structure by adding or removing parents of an object through simple actions such as menu commands or drag and drop operations. In addition, the precedence of parents in a heterarchy can be reordered, again through a drag and drop operation. Furthermore, layers can be added to or deleted from, the program structure. For example, a new parent can be spliced between an existing parent and its children. Properties and handlers can be moved to appropriate levels of the program structure through simple operations, and the user can be provided with choices to make appropriate functionality changes to individual objects, as desired.
Further features of the invention, and the advantages offered thereby, are explained in detail hereinafter with reference to specific embodiments illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the general hardware components of an exemplary computer system;
FIG. 2 is an illustration of four exemplary buttons that constitute objects in a graphical user interface;
FIG. 3 is an example of a hierarchical program structure;
FIG. 4 is an illustration of the data file for the example of FIG. 3 ;
FIGS. 5A and 5B respectively illustrate a heterarchical program structure and its associated data file;
FIG. 6 is an illustration of a user interface window for redesigning the structure of an object-oriented program;
FIG. 7 is another example of a hierarchy into which a new object has been spliced;
FIG. 8 is an illustration of the inheritance viewer window after a spliced object has been added;
FIG. 9 is an illustration of an object editor interface together with the inheritance overviewer window;
FIG. 10 is an illustration of the data file for the structure of FIG. 7 ; and
FIGS. 11A and 11B are illustrations of the inheritance overviewer window for an example in which an object has plural parent objects.
DETAILED DESCRIPTION
To facilitate an understanding of the principles which underlie the present invention, it is described hereinafter with reference to specific embodiments. For example, a specific window design is illustrated in the accompanying drawings for the interface by which a user can redesign the structure of an object-oriented program. Furthermore, specific examples of objects and structures are described in the context of the prototype approach to object-oriented systems. It will be appreciated, however, that the invention is not limited to the specific described embodiments. Rather, it will find applicability in any type of object-oriented programming environment, and with a wide variety of user interfaces.
Generally speaking, the present invention is directed to a system for dynamically designing the hierarchical or heterarchical structure of an object-oriented computer system. While the particular hardware components of a computer system do not form a part of the invention itself, they are briefly described herein to provide a thorough understanding of the manner in which the features of the invention cooperate with various components of a computer system, to produce the desired results.
Referring to FIG. 1 , a typical computer system includes a computer 10 having a variety of external peripheral devices 12 connected thereto. The computer 10 includes a central processing unit 14 and associated memory. This memory generally includes a main memory which is typically implemented in the form of a random access memory 16 , a non-volatile memory that can comprise a read only memory 18 , and a permanent storage device, such as a magnetic or optical disk 20 . The CPU 14 communicates with each of these forms of memory through an internal bus 22 . The peripheral devices 12 include a data entry device such as a keyboard 24 , and a pointing or cursor control device 26 such as a mouse, track ball, pen or the like. A display device 28 , such as a CRT monitor or an LCD screen, provides a visual display of the information that is being processed with the computer, for example the contents of a document or a computer generated image. A hard copy of this information can be provided through a printer 30 , or similar such device. Each of these external peripheral devices communicates with the CPU 14 by means of one or more input/output ports 32 on the computer.
In the context of the present invention, at least some of the software which resides in the RAM 16 of the computer, and which is executed by the computer to perform desired tasks, is structured as an object-oriented program. For example, this software could comprise the operating system for the computer, by means of which it performs such basic tasks as responding to input commands entered by the keyboard 24 and the cursor control device 26 , reading information from each of the forms of memory 16 , 18 and 20 , providing a graphical user interface on the display device 28 , and communicating with the printer 30 . Alternatively, or in addition, the object-oriented software can comprise one or more application programs which enable the user to perform specific tasks with the computer, such as word processing, graphic design and communications. As described previously, in an object-oriented system, each object is an autonomous agent that has associated properties and handlers. The various objects communicate with one another to carry out one or more specific tasks. Thus, for example, in an operating system, one object may be responsible for sending data to and controlling the operation of the printer 30 , another object may control the writing of graphical information on the display 28 , and another object can carry out the tasks of reading and writing information from the disk 20 . Similarly, in a word processing program, one object may control a scrollbar to present different portions of the text in a display window, and various other objects may perform the operations of respective tools in a toolbar.
In the following description, the present invention will be explained with reference to objects that pertain to elements of a graphical user interface, namely user-actuated buttons. An example of four such buttons is shown in FIG. 2 . These buttons might form part of a dialog box or other user interface element which is displayed on the display device 28 to permit the user to select from among various available choices for a particular operation or feature. It will be appreciated that this particular set of objects is merely exemplary for purposes of explaining the present invention. The applicability of the features of the present invention to all types of objects will become apparent from this example.
Initially, when an object-oriented program is designed, the four buttons might have a hierarchical relationship as depicted in FIG. 3 . All of the buttons inherit from a common parent, a round rectangle object 34 . As such, they inherit the properties of the round rectangle object. For example, they all have the same shape, i.e., a rectangle with rounded corners. In addition, they inherit the functional properties of the round rectangle. For example, each one may become highlighted if the user actuates a cursor control device when the cursor is located over the button, to select that particular button. The various buttons can also have individual properties which are not inherited from the parent object 34 , and therefore not necessarily shared among them. For example, each button might be a different color.
The properties and handlers of the buttons, as well as their hierarchical ancestors and descendants, are recorded in a persistent data file that is stored within the permanent memory 20 of the computer. In addition, this data file, or one created from the information contained in the data file, resides in the working memory 16 of the computer while the program is running. An example of the data file for the particular hierarchical arrangement of FIG. 3 is shown in FIG. 4 . Referring thereto, the file is structured as a database. Each object effectively forms a record in the database, and the fields for each record indicate that object's associated properties, handlers, parents and children. In the example of FIG. 4 , each object is shown having only one property and one handler. In practice, each object can have any number of associated properties and handlers.
The example of FIG. 3 pertains to a hierarchical object-oriented system, in which each object has only one parent object. In a heterarchical system, any object can have more than one parent. An example of such a system is shown in FIG. 5A , in which each of the first and fourth buttons inherit properties from two additional parent objects 35 a and 35 b , respectively. The data file which pertains to this structure is shown in FIG. 5 B.
In the data files of FIGS. 4 and 5B , the entries for the parents and children of each object are shown as the names of the respective objects. In practice, the actual entries in the file may comprise pointers to the location of the records for those objects. Thus, if the record for the round rectangle object is stored at memory address 1234, the entry under “Parents” for each of the four button objects would be a pointer to address 1234. This pointer functions as an indicator that each button inherits the properties and handlers of the object whose record is stored at that location.
By storing the persistent data relating to the characteristics and relationships of objects in this manner, the ability to dynamically edit the features of objects, either programmatically or via direct manipulation, is greatly facilitated. Changes that are made to the data file are immediately implemented, and can be saved and loaded at a later time with no additional effort being required. This editing capability is further facilitated by means of a graphical interface which permits the user to readily view and manipulate the structural relationships of the objects. One example of such a user interface is depicted in FIG. 6 . Referring thereto, the particular interface is a window 36 that is labelled an “Inheritance Overviewer”. The inheritance overviewer window 36 is divided into three panels. The top panel 38 is an input panel which enables the user to specify an object, or group of objects, to be viewed or edited. The lower left panel 40 , labelled the parent panel, lists the parents of the selected object identified in the input panel. If multiple objects have been selected by the user, for example all four of the buttons illustrated in FIG. 3 , only parents which are shared by all of those objects are displayed in the parent panel 40 . The lower right panel 42 , labelled the children panel, displays the descendants of the selected object. If multiple objects are selected, shared descendants are displayed. In the example of FIG. 3 , none of the selected buttons has any descendants, and so no children are shown in the panel 42 .
In addition to providing information to the user about the inheritance hierarchy of selected objects, the inheritance overviewer permits a user to redesign the program structure, for example to add new parents. For this purpose, the window can be provided with a menu item 44 pertaining to parents. By selecting this menu item, a submenu (not shown) is displayed which contains commands to add or delete a parent. If the user chooses the command to add a parent, a dialog box prompts the user to enter the name of a new parent, which will then appear in the list of parents in the panel 40 . Similarly, a children menu item 46 can be provided, to permit the user to add or delete children for the selected object.
When one of these operations is performed via the inheritance overviewer window, the contents of the data file is modified to reflect the new relationship. For example, if the user decides to change the structure of FIG. 3 to that of FIG. 5A , by adding two new parent objects 35 a and 35 b , records for these two new parent objects are added to the database, as shown in FIG. 5 B. In addition, parent pointers to these new parent objects are added to the records for their children. If the parent objects are already present in the database, the pointers for the existing objects are modified accordingly. The modification of the contents of the database is carried out by means of a software module associated with the inheritance overviewer window, which itself can form another object. Whenever the user opens the inheritance overviewer window, this module is launched and responds to user commands within the window to modify the contents of the database file accordingly.
A further feature of the present invention which is facilitated by the inheritance overviewer window and the data file structure for object information is the ability to add or delete levels of the hierarchy. For example, it is possible to splice a new parent between currently established parents and children. Referring to FIG. 4 , it can be seen that button numbers 1 , 2 and 3 all have a common handler, labelled “function 2 ”. Rather than duplicate the code which executes function 2 for each of these three objects, it is preferable to create a single object which exhibits this functionality, and to have each of the three buttons descend from it. For example, the function may be for the button to generate an audible “click” whenever the user actuates it. A single object which exhibits this functionality is labelled a “superbutton” in this particular example. A new hierarchy which contains a superbutton object 48 spliced between the round rectangle object 34 and each of buttons 1 , 2 and 3 is illustrated in FIG. 7 .
To perform this operation of splicing the superbutton object 48 into the hierarchy, the user selects the objects for buttons 1 , 2 and 3 in the input panel 38 of the inheritance overviewer window 36 , and then issues a command to splice a new parent. This command can be available, for example, as part of a submenu which appears under the parents menu command 44 . In response to selecting the splice command, the selected objects are moved from the input panel 38 to the children panel 42 , and the user enters the name of the new parent in the input panel. The result is as shown in FIG. 8 , which corresponds to the hierarchical structure shown in FIG. 7 .
Once the structure of objects has been established, the user can associate the desired properties and handlers with the new parent. In a preferred embodiment of the invention, this task is carried out by means of a drag and drop operation. To do so, the user can be provided with another form of interface that permits all of the properties and handlers for a given object to be viewed. An example of such an interface is shown in FIG. 9 . An object editor window 50 is illustrated beside the inheritance overviewer window 36 . This window also contains three panels. The top panel 52 is an input panel by which the user identifies an object of interest. The middle panel 54 lists all of the properties for that object, and the lower panel 56 sets forth the handlers for that object. In the specific example being described, the superbutton was spliced into the hierarchy to provide a single object which exhibited the functionality associated with buttons 1 , 2 and 3 . Therefore, it is desirable to transfer this functionality from one of these three buttons to the newly created superbutton. To do so, the user can select the handler 58 which performs that function and drag it from the object editor window 50 onto the name of the superbutton object in the inheritance overviewer window 36 . By releasing the cursor control device when the handler is positioned over the name of the object, i.e., dragging and dropping the handler, it becomes associated with the newly created superbutton. When this action is performed, the database file in the memory 20 is modified to indicate the changed information. The modified database file is illustrated in FIG. 10 . Referring thereto, it can be seen that a new object has been added to the file, namely the superbutton. Furthermore, the handler which was previously associated with buttons 1 , 2 and 3 has been moved to the superbutton object.
A similar type of operation can be employed for properties. A user can select a property from the object editor window 50 and drag it onto the name of an object appearing in the inheritance overviewer window 36 . If the selected property is local to the child and not previously defined for the parent, the property is moved to the parent. In this case, all of the children which descend from that parent, including the original, will inherit this property. The result of this action is to encapsulate and localize the property to the parent. If the property already existed in the parent, its value will be set to that of the child, thereby allowing the child to inherit the value from the parent. Subsequently, a dialog box can be presented, to permit the user to choose if all of the descendants should inherit this value, or it they should keep their current values. For example, it may be desirable to make gray as the default button color, but to leave the other existing buttons their current color. In this situation, the color property from the gray button can be dragged to the superbutton object, to establish its value as the default value. Via a dialog box, the user can choose whether or not to set that same value for each of the existing descendants.
This same drag and drop functionality can be employed to add parents and children in lieu of using the commands in the inheritance overviewer window. More particularly, whenever the name of a desired new parent or child appears in any interface element, such as a panel of the object editor window 50 , the user can drag that name from its location and drag it into the appropriate panel 40 or 42 of the inheritance overviewer window 36 . Through such an action, the dragged object is established as a new parent or child of the object whose name appears in the input panel 38 , similar to carrying out the add command from the menu items 44 and 46 .
The dragging and dropping operation can also be employed within the inheritance overviewer window 36 to reorder the precedence of parents. In a heterarchical system, such as the one shown in FIG. 5A , when an object has two or more parent objects, those parents are given an order of precedence. If the parents have any conflicting properties, the precedence ordering determines which of the properties is controlling for the child object. For instance, in the example of FIG. 5A , if the object 35 a has a shape property which specifies an oval shape, it conflicts with the round rectangle shape property of the object 34 . Assuming that object 34 has precedence, as shown in FIG. 11A , the object “Button 1 ” would have a round rectangle shape. If the user prefers that the object have an oval shape, the name of the object 35 a can be dragged on top of the object 34 within the panel 40 of the inheritance overviewer window 36 . The result of this action is to give the object 35 a precedence over the object 34 , as depicted in FIG. 11 B. Within the database file, the precedence order of parents might be indicated by another field for each record (not shown in FIG. 5 B), which is modified accordingly in response to the drag and drop operation.
From the foregoing, it can be seen that the present invention provides a system which enables a programmer to easily generate design iterations in an object-oriented system, and thereby converge more quickly on an optimal solution. The flexibility of this system also permits the programmer to readily keep up with changes in product specifications and/or user needs. Furthermore, splicing objects into an existing hierarchy is readily facilitated, without the need to recompile code before the splice becomes effective.
It will be appreciated by those of ordinary skill in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.
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An object-oriented computing environment stores information relating to objects in a data file, and manipulates the information in the data file through a suitable user interface. The interface permits a user to completely redesign a program structure by adding or removing parents of an object through simple actions such as menu commands or drag and drop operations. The precedence of parents in a heterarchy can be reordered, again through drag and drop operation. A new parent can be spliced between an existing parent and its children. Properties and handlers can be moved to appropriate levels of the program structure through simple operations, and the user can be provided with choices to make appropriate functionality changes to individual objects, as desired.
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BACKGROUND OF THE INVENTION
This invention relates to a coke oven and more particularly, a coke oven having an improved regenerator for reducing nitrogen oxides in waste gas generated in the coke oven thereby preventing environmental pollution.
In a known horizontal type coke oven, such as an Ottotype, Koppers-type and Carl-Still-type coke oven, fuel gas fed from one duct is heated and burned in a heating flue chamber for a predetermined time and the waste gas is discharged into atmosphere through a duct, a regenerator disposed below the heating flue chamber and a flue. The temperature of the waste gas entering into the regenerator is generally is about 750-1000° C. In this process, bricks constituting the walls of the regenerator is heated by the high temperature waste gas and the heat is stored in the regenerator. The heat stored in the regenerator is fed to the heating flue chamber through another duct and is used for preheating air for the combustion.
The waste gas contains harmful substances, for example nitrogen oxides (abbreviated as NO x hereinbelow), which cause environmental air pollusion. In the prior art, such NO x were discharged through the flue of the coke oven into the atmosphere without being subjected to any treatment for removing NO x therefore, the discharged NO x became one factor that causes photochemical smog.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide an improved coke oven capable of discharging the waste gas containing substantially no NO x into the atmosphere through the flue of the coke oven.
According to this invention, there is provided a horizontal type coke oven in which waste gas generated in a heating flue chamber is discharged into a regenerator cell. The coke oven is provided with nozzle openings for injecting ammonia or ammonia precursor into a flow passage of the waste gas from the heating flue chamber and at a position where the temperature of the waste gas is 750-1000° C. so as to reduce nitrogen oxides in the waste gas with the ammonia or ammonia precursor.
In the coke oven of this invention, the above described object is accomplished by applying the fact that NO x are reducted to molecular nitrogen with ammonia at a temperature of about 750-1000° C. Namely, NO x in the waste gas are removed by injecting ammonia into and mixing it with the waste gas, the temperature of which is about 750-1000° C. near the inlet at the top of the regenerator cell, in the presence of oxygen, and NO x are then reduced to molecular nitrogen in the absence of oxygen.
The injection of the ammonia can be made by any known means, but usually, it is advantageous to inject the ammonia, which is fed from a supply tank disposed externally of the coke oven, into the regenerator cell through a duct and the walls of the regenerator cell. In one typical manner, the ammonia is injected into the regenerator cell directly from the inside surface of the wall thereof or through a pipe made of quartz, for example, and provided with a plurality of nozzles. However, any other manner can be used so long as the ammonia can be sufficiently contacted to and mixed with the waste gas. In this case, since an ammonia feed pipe is located under high temperature condition, it is desirable to prevent the thermal decomposition of the ammonia in the feed pipe before it is injected into the waste gas by applying heat shielding means such as a water jacket or by using a pipe made of quartz or ceramics. The amount of ammonia to be injected is selectively used among 0.8-20 moles, preferably, 0.8-10 moles and industrially, 0.8-5 moles with respect to 1 mole of NO of NO x in the waste gas.
Furthermore, it is not necessary to store the ammonia as pure ammonia before use and it is also possible to use substances such as ammonium carbonate or the like, generally called ammonia precursor, which are easily decomposed at a temperature of about 750-1000° C. to generate ammonia when the substance is mixed with the waste gas containing NO x . Furthermore, an ammonia mixture such as coke oven gas containing hydrocarbon gas may also be used instead of the pure ammonia.
Although the ammonia is usually diluted before the use with steam or inert gas such as nitrogen or the like, it is also possible to feed the ammonia together with hydrogen, and in the latter case, NO x in the waste gas can be effectively reduced by changing the mixing ratio of the ammonia with the hydrogen in accordance with the temperature of the waste gas.
This invention will become more apparent from the following description made in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings;
FIG. 1 is a partial transverse sectional view of one embodiment of a coke oven according to this invention;
FIG. 2 is a partial longitudinal sectional view of the coke oven shown in FIG. 1;
FIG. 3 is a partial transverse sectional view of another embodiment of a coke oven according to this invention;
FIG. 4 is a partial longitudinal sectional view of the coke oven shown in FIG. 3;
FIG. 5 is a partial longitudinal sectional view of a further embodiment of a coke oven according to this invention;
FIG. 6 is a partial longitudinal sectional view of a still further embodiment of a coke oven according to this invention; and
FIG. 7 is a partial longitudinal sectional view of the other embodiment of a coke oven according to this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In a perferred embodiment of the coke oven of this invention, shown in FIGS. 1 and 2, two nozzles 10 are disposed to oppose the side walls 7' of the top portion of a regenerator cell 7. Coke oven gas is fed into heating flue chambers 1 through a main pipe 3, branch pipes 4, jet pies 5 and refractory burners 2 and burnt thereby. Waste gas generated in the heating flue chambers 1 is discharged to the outside of the coke oven through gas ducts 6, regenerator cells 7 located below the heating flue chambers 1, sole flues 8 and a waste gas flue 9, as shown by arrows in FIGS. 1 and 2. Nozzles 10 are provided for the regenerator cell 7 at the upper end of the side walls thereof and opened in the regenerator cell and ammonia or ammonia precursor is injected into the regenerator cell 7 through a main pipe 12, ammonia guide pipes 11 and the nozzles 10. In this case, it is desirable to inject ammonia at the same time as the discharge of the waste gas in the regenerator cell 7. Reference numeral 13 designates an oven chamber, and in the illustrated embodiment, regenerator cell filling bricks are not shown.
The ammonia is mixed with the waste gas having a temperature of about 750-1000° C. in the regenerator cell 7 in a manner described herein above and NO x in the waste gas are then reduced to the molecular nitrogen. Thus, the exhaust gas discharged from the waste gas flue 9 contains substantially no NO x .
FIGS. 3 and 4 show partial sectional views of another embodiment of the coke oven of this invention, in which the same reference numerals are applied to the same parts shown in FIGS. 1 and 2 (the same is true in the other embodiments described hereinafter). In FIGS. 3 and 4, the ammonia guide pipes 11 further extends into the regenerator cell 7 through the side walls thereof as through pipes 11'. The provision of a plurality of nozzles 10 ensures uniform injection of the ammonia into the regenerator cell 7 at the top portion thereof and the more efficient mixing of the ammonia with the waste gas.
In FIG. 5 a horizontal obstruction wall 14 is disposed at the upper portion of the regenerator cell 7 where the temperature of the waste gas is about 750-1000° C. so that the waste gas discharged from the ducts 6 collides against the obstruction wall 14 at substantially right angles, then flows therealong and finally enters into the inside of the regenerator cell 7 through a gas passage 15 formed between the obstruction wall 14 and the inside surface of the side walls of the regenerator. In this embodiment, the ammonia is injected from the nozzles 10 provided for the opposing side walls 7' and mixed with the waste gas at the considerably narrow gas passage 15. Therefore, NO x contained in the waste gas of the temperature of about 750-1000° C. are reduced to the molecular nitrogen before entering into the inside of the regenerator cell 7. Thus, the waste gas discharged from the waste gas flue 9 contains substantially no NO x . In this modified coke oven, since the whole waste gas flows through the considerably narrow gas passage 15, the ammonia can be smoothly and uniformly injected into and mixed with the waste gas, whereby NO x are effectively reduced and removed.
With a further modified coke oven shown in FIG. 6, the regenerator cell 7 is divided into two chambers 7a and 7b by a horizontal obstruction wall 16 disposed across the side walls 7', and a waste gas conduit system 20 for communicating the upper chamber 7a with the lower chamber 7b is located to the outside of the regenerator cell 7. Heat recovery means, such as a heat exchanger 19 is provided for the waste gas conduit system 20 and a plurality of nozzles 10 for injecting the ammonia are provided for an ammonia mixing pipe 17 on the upstream side of the conduit system 20. The upper chamber 7a is constructed in a zone where the temperature of the waste gas supplied from ducts 6 is about 750-1000° C. In this embodiment, the coke oven gas is fed into the heating flue chamber 1 through the main pipe 3, the branch pipes, and the jet pipes 5 and burnt by the refractory burner 2. The waste gas generated in the heating flue chamber 1 enters through the ducts 6 into the upper chamber 7a of the regenerator cell 7. The waste gas is then guided to the conduit system 20 and mixed with the ammonia injected from the nozzles 10. The waste gas is introduced into the lower chamber 7b of the regenerator cell 7 through the ammonia mixing pipe 17, the heat exchanger 19 and a guide pipe 18, then preheats the regenerator cell 7 and is discharged externally of the coke oven through the waste gas flue 9.
NO x in the waste gas are reduced to the molecular nitrogen when it passes through the ammonia mixing pipe 17, and the provision of the heat exchanger 19 compensates for the heat loss of the waste gas caused by the passage thereof through the conduit system 20.
In the coke oven shown in FIG. 7, the regenerator cell 7 is designed to be more compact than a conventional horizontal type coke oven. The sole flue 8 in this coke oven is connected with the waste gas flue 9 provided with a plurality of ammonia injecting nozzles 10 and a heat exchanger 19. Although the temperature of the waste gas entering into the regenerator through the ducts 6 is about 900-1100° C., the regenerator of the coke oven of this type is designed so that the temperature thereof will be about 750-1000° C. when it is discharged from the sole flue 8.
Thus, NO x in the waste gas are reduced to the molecular nitrogen with the ammonia injected from the nozzles 10 while they pass through the waste gas flue 9, and the waste gas discharged from a stack 21 contains substantially no NO x . The heat recovered by the heat exchanger 19 is used for preheating air to be supplied to the regenerator cell 7.
As is understood from the foregoing description made in conjunction with the preferred embodiments of this invention, NO x contained in the waste gas of the coke oven can be reduced to the molecular nitrogen and removed by feeding the ammonia or ammonia precursor, thus preventing the environmental air pollusion, and since the regenerator is constructed compact, the whole structure of the coke oven is made small and fundation work and brick pilling work which are essential for the conventional horizontal type coke oven are simplified or eliminated, thus reducing the cost of construction.
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In a horizontal type coke oven, high temperature waste gas generated in a heating flue chamber and containing nitrogen oxides is discharged into a regenerator. There are provided nozzle openings for injecting ammonia or ammonia precursor to the high temperature waste gas at a position where the temperature of the waste gas is about 750°-1000° C. so as to reduce the nitrogen oxides in the waste gas with the ammonia or ammonia precursor.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for hydrogenating low rank coal to liquid and gaseous hydrocarbons.
2. Description of the Prior Art
A number of ebullated bed processes have been developed for the conversion of coal to liquid and gaseous hydrocarbons. These processes include one requiring two catalytic stages U.S. Pat. No. 3,700,584, a second process having a countercurrent transfer of catalyst from the second stage to the first stage (U.S. Pat. No. 3,679,573), and a single stage non-catalytic technique (U.S. Pat. No. 3,617,465). Satisfactory results can consistently be obtained with these methods with feeds other than low rank coals. However, when low rank coals are treated, conversion and, as a result, operability have not been satisfactory. These unsatisfactory results are caused by the relatively low hydrogenation rates of these coals and, in the case of the catalytic processes, by the rapid inactivation of the catalyst by the metallic impurities contained in the coal and carbon deposition.
SUMMARY OF THE INVENTION
It is the principal object of the present invention to provide a two stage process for the hydrogenation of low rank coal to produce hydrocarbon liquid and gaseous products wherein improved conversion and operability are achieved.
We have now discovered that by processing low rank coal in two reaction zones connected in series, with the first stage reactor attaining a limited degree of conversion of coal to tars and operating without catalyst, at significantly higher solids concentration and at a higher temperature than the second stage catalytic reactor, and the second stage reactor operating at temperatures and pressures designed to maximize hydrogenation of the tars to lighter liquid and gaseous hydrocarbons, improved operation and a significantly higher level of coal conversion can be achieved. The average temperature in the first stage non-catalytic reaction zone should exceed the average temperature in the second stage catalytic reaction zone by at least about 25° F. (˜14° C.) but preferably, by not more than about 75° F. (˜42° C.).
This temperature differential provides at least two significant advantages. First, since the hydrogenation rate is a function of reaction temperature, the higher temperature results in greater coal conversion. Second, the use of a lower temperature in the second stage decreases the amount of carbon deposited on the catalyst, thereby increasing catalyst life.
The temperature in the first stage reactor should preferably be about 825°-875° F. (˜441°-468° C.), while the temperature in the second stage catalytic ebullated bed reactor should preferably be about 800°-850° F. (˜427°-454° C.). Reactor pressure in both stages should be 1500-3500 psi (˜100-240 atm) partial pressure of hydrogen, with the pressure in the first stage reactor usually being slightly higher than in the second stage to permit forward flow without pumping. The solids concentration of unconverted coal and ash in the first stage reactor should be controlled by recycle of clarified liquid to be about 15-30 weight percent, and the solids concentration in the second stage reactor should be maintained by clarified liquid recycle to be about 10-20 weight percent.
The first stage reactor may operate with or without the presence of a high density, non-catalytic contact material. The use of such contact material is desirable when the reactor is operated at the higher end of the temperature range since the material limits the deposition of coke. When contact material is used, it should consist of high density, low porosity solids, for example tabular alumina having a particle density of 3.0 gm/cc or higher.
The second stage catalyst may be any catalyst used in the hydrogenation of coal and is preferably selected from cobalt, molybdenum, nickel, tungsten, tin, and iron deposited on a base of γ-alumina, magnesia, and silica. Such catalyst particles generally have a density of less than 1 gm/cc.
DESCRIPTION OF THE DRAWING
The drawing is a diagrammatic view of a typical process suitable for the two stage hydrogenation of coal.
DESCRIPTION OF PREFERRED EMBODIMENT
Low rank coal, such as semi-bituminous, sub-bituminous, brown coal or lignite, is introduced at 10 into a preparation unit 12, wherein the coal is dried to remove substantially all surface moisture, ground to a desired size and screened. For the purpose of this invention, it is preferable that the coal have a particle size between about 20 to about 200 mesh (U.S. sieve series), i.e., the coal particles all pass through a 20 mesh screen and substantially all (not less than 80%) of the coal particles are retained on a 200 mesh screen. However, the preciseness of size may vary between different types of coal.
The coal particles are discharged at 14 into slurry tank 16 where the coal is blended with a slurrying oil introduced at 18. This oil is preferably a recycle stream produced by the hydrogenation of the coal. To establish an effective transportable slurry, the ground coal should be mixed with at least about an equal weight of slurrying oil, but usually with not more than 10 parts of oil per part of coal.
The coal-oil slurry is then pressurized by pump 20 and passed via line 21 through the slurry heater 22, where the slurry is heated to near reaction zone temperature. The heated slurry is then discharged at 24 into the first stage reactor feed line 26, wherein it may be supplied with heated makeup hydrogen from line 28 as well as recycled hydrogen from line 30.
The hydrogen and coal-oil slurry is then introduced into the first stage reactor 32. In this reactor the hydrogen/coal/oil mixture is maintained at a sufficient pressure and temperature for limited conversion of coal primarily to heavy liquid hydrocarbons without hydrogenating substantial amounts of the tars to lighter liquid and gaseous products. Hydrogenation is achieved in the first zone without the use of a catalyst. This eliminates the fluidization difficulties of prior art processes which used a catalyst in the first stage since only unreacted coal and ash particles are present in the bed. Alternatively, a high density contact material such as tabular alumina can be used and the first stage can be operated as an ebullated bed.
If the first stage is operated as an ebullated bed, liquid may be recycled internally within the reaction zone 32 to maintain ebullation. In such case, a standpipe 34 having its top end open and above the upper level of ebullation 38 may be used to pass liquid from the top of the reaction zone 32 to recycle pump 45 disposed below distributor 42 in the bottom of the reaction zone 32, with the liquid discharged by the submerged pump flowing upwardly again through the mass of ebullated solids. In lieu of distributor 42 which uniformly distributes the flow of liquid and gasiform material to the entire mass of ebullated solids in reaction zone 32, the bottom of the reactor may be tapered or funnel-shaped so that the admixed liquid and gasiform streams introduced into the bottom of the funnel will flow upwardly through the entire ebullated mass. When no contact material is contained in vessel 32 the standpipe 34 and pump 45 can be eliminated.
As a further alternative, the liquid may be recycled externally of the reaction zone 32. In such a case, the effluent line 48 can be connected to line 26 via a conduit and a pump (neither shown) to maintain the desired superficial upward liquid velocity in the reaction zone 32.
The operating conditions of temperature and pressure in the first stage reaction zone 32 are in the range of from about 800° F. (˜427° C.) to about 900° F. (˜482° C.), preferably from about 825° F. (˜411° C.) to about 875° F. (˜468° C.), and with a hydrogen partial pressure of from about 1500 to about 3500 psig (˜100-240 atm).
If the first stage is operated as an ebullated bed, the gross density of the contact material in the first stage should preferably be between about 25 to about 100 pounds per cubic foot (˜400-1600 g/l). The flow rate of the liquid should preferably be between about 5 and about 120 gallons per minute per square foot of horizontal cross-section of the ebullated mass (˜200-4900 l/min/m 2 ), and the expanded volume of the ebullated mass should usually be no more than about double the volume of the settled mass and preferably about 30-80 percent greater.
After the coal-oil slurry is partially hydrogenated in the first stage reaction zone 32, the entire effluent stream, which comprises heavy tars of average molecular weight of 500-1000, containing 5-6.5% hydrogen, which are essentially non-volatile at 1000° F., partially unconverted coal, mineral matter, slurry oil, unconsumed hydrogen, gaseous and lighter liquid hydrocarbonaceous products and by-products of hydrogenation, is withdrawn from the top of reaction zone 32 via line 48 and fed to input conduit 50 of the second stage ebullated bed reaction zone 52. If needed, additional recycle hydrogen may be fed into the second stage reaction zone 52 via line 53. A hydrogenation catalyst bed is provided in the second stage reaction zone 52 by introducing fresh or uncontaminated catalyst via line 54. The partially spent or contaminated catalyst is withdrawn from the reaction zone 52 via line 56, and is replaced at a sufficient rate to maintain the desired catalytic activity in the second stage reaction zone 52. The spent catalyst may be regenerated by conventional techniques or discarded. The upper level of ebullation in reaction zone 52 is indicated at 58.
The catalyst used in the second stage is preferably cobalt, molybdenum, nickel, tungsten, or tin deposited on a base of γ-alumina having a particle density of less than 1 gm/cc. It is preferably in the form of beads, pellets, lumps, chips or like particles and has a size of at least about 1/32 inch (˜0.08 cm) or more frequently in the range of 1/16 to 1/4 inch (˜0.16-0.64 cm) (i.e., between about 3 and 12 mesh screen on the U.S. sieve scale). The size and shape of the particles used in any specific process will depend on the particular conditions of that process, e.g., the density, velocity, and viscosity of the liquid involved in that process.
The second stage reaction zone 52 should be operated under the conditions of temperature, pressure, and liquid feed rate most suited to provide maximum hydrogenation of the tars to lighter liquid and gaseous hydrocarbons such as temperature of 775°-875° F. (˜413°-468° C.) to preferably 800°-850° F. (˜427°-454° C.). The temperature should preferably be at least 25° F. less than that of the first stage. Reactor 52 can be provided with a standpipe 60, circulation pump 62, and distributor 64 for internal recycle of liquid to maintain the desired superficial liquid velocity and ebullation. External recycle of liquid can alternatively be employed as in the first stage.
The coal feed rate through the first stage reaction zone 32 and the second stage reaction zone 52 is from about 15 to about 100 pounds per hour per total cubic foot of the two reaction zones 32 and 52. The total hydrogen feed rate to both the first and second stage reaction zone 32 and 52 is generally from about 20 to about 60 standard cubic feet per pound of coal and the separate hydrogen feed rate in each of said two zones is usually proportional to the zone volume or size thereof. The ratio of the volume or size of the first stage reaction zone 32 to the volume or size of the second stage reaction zone 52 generally is from about 1:3 to about 3:1 and preferably is about 1:2 to 1:1.
Thus, where the volume of the first stage reaction zone 32 is twice that of the second stage reaction zone 52 and where the total hydrogen feed rate through both of the two reaction zones 32 and 52 is about 30 standard cubic feet per pound of coal, the directly proportional separate hydrogen feed rate through the first stage reaction zone 32 is about 20 standard cubic feet per pound of coal and in the second stage reaction zone 52 is about 10 standard cubic feet per pound of coal.
It will be appreciated that the first and/or second stage reaction zones 32 and 52 can be a single ebullated bed reactor each or a plurality of ebullated bed reactors connected in parallel. For example, for reasons of economy in equipment costs the first stage reaction zone 32 can be two ebullated bed reactors arranged in parallel and the second stage reaction zone 52 can be a single ebullated bed reactor, with all three ebullated bed reactors being of equal size or volume. In such an arrangement, the ratio of volume or size of the first stage reaction zone to the volume or size of the second stage reaction zone would be 2:1 and where the total hydrogen feed rate to both the first and second stage reaction zones is about 30 standard cubic feet per pound of coal, the directly proportional separate hydrogen feed rate to each of the three equal volume reactors would be 10 standard cubic feet per pound of coal.
A gasiform effluent stream is withdrawn from the top of the second stage reaction zone 52 via line 66 and passed to a separator 70 wherein hydrocarbonaceous vapors, any entrained solids or liquids, by-product gases and excess hydrogen gas can be separated from one another to the extent desired and the recovered hydrogen gas recycled to the first stage reaction zone 32 via line 72. If desired, some recovered hydrogen gas can also be recycled to the second stage reaction zone via line 53.
A solids-containing liquid effluent stream is withdrawn from the second stage reaction zone 52 via line 68 and fed to separator 74 for separation and recovery of the hydrocarbonaceous liquid products and solids such as unconverted coal (char) and ash.
Overhead liquid stream 75 is passed to a distillation zone 76, from which light gas and liquid material is recovered as product at 77 and heavy liquid is withdrawn at 79.
The bottoms liquid stream 78 withdrawn from gas-liquid separation step 74 contains some particulate solids and is passed to a liquid-solids separation zone 80, which is preferably a liquid hydroclone separator unit. To help control the concentration of coal solids in the first stage reactor 32 within a desired range, overflow liquid 82 containing a reduced concentration of solids can be returned to the reactor 32 via slurrying liquid stream 18. A solids-enriched stream is withdrawn at 84 for further processing as desired, such as by vacuum distillation at 86 for further recovery of the oil portion. The overhead liquid stream 87 from the vacuum distillation may be combined with liquid stream 79 to provide blended liquid product 96.
If closer control of coal solids concentration in the second stage reactor 52 is needed in order to limit the solids concentration within the desired range, a portion of the clarified liquid stream 82 can be returned to the second stage reactor 52 via line 83. Any overhead liquid not recycled to the reactor can be passed via stream 85 to vacuum distillation at 86 or may be withdrawn via stream 85a as product 96. Heavy material is removed at 88.
To assist in the separation and recovery of gaseous and liquid products from gaseous effluent stream 66 in separation system 70, it is preferable to cool the effluent stream 66 against at least a portion of recycle hydrogen stream 72 recovered in unit 70. Such cooling of the reactor gaseous effluent stream desirably reduces the heating requirements for the recycle hydrogen, as provided in heater 90. Specifically, gaseous effluent stream 66 withdrawn from second stage reactor 52 is preferably cooled against recycle hydrogen stream 92 in heat exchanger 93.
To assist in controlling temperature in the second stage reactor 52 within the desired range, effluent stream 48 from first stage reactor 32 may preferably be cooled against at least a portion 94 of recycle hydrogen stream 72 in heat exchanger 95. Such heat exchange with reactor effluent 48 also reduces the heating requirements for the recycle hydrogen as provided by heater 90.
An alternative and preferred arrangement for supplying the high purity makeup hydrogen to first stage reaction zone 32 is provided by introducing it via stream 29 immediately upstream of slurry heater 22. Introducing hydrogen into the slurry stream at this point reduces the liquid viscosity and thus facilitates heat transfer in heater 22. Also if desired, a portion of the warm recycle hydrogen may be similarly introduced via stream 31 upstream of slurry heater 22 to facilitate the slurry heating process.
Low rank coals for which this invention is useful include Wyodak, Big Horn, Black Mesa, Gelliondale, and Kaiparowits type coals.
An example of the results obtained by the claimed invention is given in the first column of the following tabulation. These results are contrasted with those obtained by alternative methods of processing the same coal in a two stage system with catalyst in both reactors (column 2), and in single stage systems with (column 3) and without (column 4) catalyst. The coal feed rate was 30 pounds per hour of Wyodak coal in each case and the hydrogen partial pressure was 1800 psig in the reactor effluent vapor stream. The recycled slurrying oil quantity and composition was adjusted in each case to maintain the slurry effluent concentration shown in order to remain within operable limits.
______________________________________ 1. 2. 3. 4. Two Two Single SingleSystem Stage Stage Stage Stage______________________________________First StageVolume .333 .667 1.000 1.000Containing Catalyst No Yes Yes NoTemperature, °F 850 825 825 850First Stage EffluentSolids, Wt% 30 20 20 23Tars, Wt% 30 15 15 37Distillable, Wt% 40 65 65 40Second StageVolume .667 .333 -- --Containing Catalyst Yes Yes -- --Temperature, °F 825 825 -- --Second Stage EffluentSolids, Wt% 20 20 -- --Tars, Wt% 25 22 -- --Distillable, Wt% 55 58 -- --Coal Conversion, Wt%of M.A.F. Coal 94 84 81 91Liquid yields, Wt% ofDry CoalDistillable Oils 49 45 39 32Residual Oil 14 11 14 27______________________________________
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The hydrogenation of low rank coal to produce hydrocarbon liquids and gases is conducted in a first stage reaction zone at elevated temperature and pressure and without catalyst, followed by further hydrogenation of the total effluent in a second stage ebullated bed catalytic reaction zone which is maintained at slightly lower temperature. The first stage may comprise an ebullated bed of high density non-catalytic contact material. However, the presence of such contact material is not required. Clarified hydrocarbon liquid streams are returned to the first stage reaction zone as the slurrying oil and to the second stage zone as recycle oil to maintain a significantly high percentage of unconverted coal solids in the first stage reaction zone than in the second stage zone. This two stage reaction arrangement produces a high percentage conversion of the low rank coal to liquid and gaseous products with good process operability.
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BACKGROUND OF THE INVENTION
Vehicles having metal roofs and side walls often include openings with vent panels for purposes of ventilation, light, and sometimes as an escape path. It is desirable that such vent panels be readily and conveniently operable by one hand, preferably in a simplified single motion; that the operating means for raising and lowering the vent panel not obstruct the view through the opening in vent closed position or along the vehicle; and that the operating means be as much out of the way as possible and not project into the interior space of the vehicle to constitute a hazard. While the operating means is preferably out of the way yet the operating means must be readily grasped and moved. It is also desired that the operating means be positive in operation and that the construction be such that the roof vent panel will be tightly sealed and will not vibrate. It is desirable that lightweight materials be used and that distortion of such lightweight materials be restricted. Since walls of different vehicles are constructed of different thickness, it is desirable that the operator means be adjustable so that a suitable close fit of the operator means may be made with respect to the wall. In addition, the operator means should be readily adapted to vent panels of different width and to framed or unframed transparent panels such as plexiglass.
Such general requirements of a means for operating or opening, closing, and latching a closure member for a framed opening in a roof is contemplated by the present invention as well as other features herein described.
Prior proposed devices for opening and closing vent panels have usually required two hands or two operations to release and lift the panel or the use of one hand to successively release, operate, or latch a vent panel. One prior proposed construction is disclosed in Green U.S. Pat. No. 1,860,245 in which a side vent window is moved to open and closed position by a handle located at the pivotal interconnection of adjacent ends of a link connected to the window and a link connected to the frame. In Binert U.S. Pat. No. 2,949,624, a lifting linkage for an upwardly pivotable vent panel in the roof structure of a vehicle is disclosed wherein the links are located along sides of the opening and are operated by a means which exerts a force parallel to the opening. The links in collapsed position lie between the bottom of the opening and the vent panel. In Belgium Pat. No. 533,581 (1954) operator means are provided for a vent panel in the roof of a vehicle wherein links are pivotally interconnected, one of the links having a pivotal connection to the vent panel and other link having a pivotal connection to the frame. The operating bar is located at the axis of the pivotally interconnected ends of said links and extends between two sets of such links to faciliate simultaneous operation.
The prior art structures mentioned did not completely meet one or more of the desirable requirements commented upon above.
SUMMARY OF THE INVENTION
The main purpose of the present invention is to provide a means for opening, closing, and latching a closure panel for an opening which will obviate disadvantages of the prior art structures and which will provide an operating means for a vent closure member having definite advantages over prior art constructions.
The primary object of the present invention therefore is to provide a means for opening and closing and latching a closure member for an opening which may be readily grasped and operated by one hand if desired.
An object of the invention is to provide an operator for a closure member wherein means are provided for adjusting the relative position of the operator means with respect to a wall structure to facilitate its operation.
Another object of the invention is to provide weather tight closing means for opening, closing, and latching a closure member for an opening in a wall wherein one of the pivotal connections may be readily adjusted to provide finger clearance to faciliate the grasping of the operator means and to hold the operator means in a non-obstructive non-hazardous position.
A still further object of the present invention is to provide means for restricting distortion of frame members used with the operator means, means for weather sealing the closure member in closed position and means for readily adapting a device of this invention to framed or unframed closures.
Various other objects and advantages of the present invention will be readily apparent from the following description of the drawings in which an exemplary embodiment of the invention is shown.
FIG. 1 is a fragmentary top plan view of a roof of a recreational vehicle equipped with a vent closure member embodying this invention.
FIG. 2 is a fragmentary perspective interior view of a means for moving said closure member into open, closed and latched position and embodying this invention.
FIG. 3 is an enlarged fragmentary sectional view taken in a vertical plane indicated by line III--III of FIG. 1.
FIG. 4 is an enlarged fragmentary sectional view taken in a vertical plane indicated by line IV--IV of FIG. 1.
FIG. 5 is a fragmentary vertical sectional view taken in the plane indicated by V--V of FIG. 2.
FIG. 6 is a fragmentary sectional view taken in the plane indicated by line VI--VI of FIG. 5, a portion of the latch members being broken away for clarity.
FIG. 7 is a fragmentary enlarged sectional view taken in the plane indicated by line VII--VII of FIG. 5.
FIG. 8 is an enlarged fragmentary sectional view showing the latch members in extended position with the closure member in raised open position.
FIG. 9 is a fragmentary sectional view showing the closure member in closed latched position and showing the operator means extending beneath and outwardly of the frame defining the opening for the closure means.
FIG. 10 is an enlarged fragmentary sectional view showing adjustment means of the pivotal connection of the upper latch member to the closure member.
FIG. 11 is an enlarged fragmentary sectional view showing the connection of an operator crossbar to the upper latch member.
FIG. 12 is a fragmentary sectional view of a modification of the means for moving a closure member into opened, closed and latched position and embodying this invention, the view being in section and illustrating the closure member in partially open position.
FIG. 13 is a fragmentary sectional view showing a removable pin at one of the pivotal connections of the operator means.
FIG. 14 is a fragmentary view showing means for connecting the operator means to the closure member.
FIG. 15 is a fragmentary section view of the means of this invention adapted to a closure member comprising an unframed glass panel.
DETAILED DESCRIPTION
Referring first to FIGS. 1, 2, and 8, a means generally indicated at 20 for opening, closing, and latching a closure member 21 hinged at 22 at one side of an opening 23 in a roof or wall 24 is generally illustrated. The hinges 22 may be of fixed type or of readily releasable type which permit the closure member 21 to be quickly removed from its position over opening 23. The latch means 20 on the side of the opening opposite hinges 22 may comprise a pair of spaced sets or assemblies 26 of latch members interconnected for simultaneous operation by a transverse crossbar 27.
The roof or wall 24 is of any suitable construction from which a framing opening 28 of selected size is cut. The framing opening 28 in this example may be provided with a lower peripherally extending Z-sectioned member 29. Upper peripheral edges of framing opening 28 are covered by a peripheral frame member 30 of suitable cross section. In this example frame member 30 includes a vertical web 31 and outwardly extending upper inclined flange 32 which overlies the edge of framing opening 28 and a bottom inwardly extending flange 33 which provides a seat for peripheral suitable sealing material 34.
Closure member 21 may be of suitable material and in this example is illustrated as a translucent or transparent glass or plastic material. Peripheral edge portions 36 of member 21 are connected to a peripheral closure frame member 37 of suitable cross section. In this example closure frame member 37 is of generally T-section having a vertical web 38, a cross flange 39 which defines with an intermediate inwardly extending flange 40 a recess for receiving sealing material 42 which sealingly and resiliently supports the peripheral edge portions 36 of closure member 21. Cross flange 39 extends outwardly and has a downturned lip 42 which provides a channel for a hollow seal member 43 adapted to bear upon top edge of web 31 as at 44 to provide weather sealing engagement therewith. The lower portion of web 38 has a bottom lip 46 adapted to sealingly engage at 47 the seal material 34.
Means 20 to open, close, and latch the closure member 21 comprises the two sets of latch means 26 interconnected by crossbar 27, the spacing between the latch means 26 being selected to provide substantially uniform pressure of the peripheral closure frame member 37 against the seal material 43, 34 when in closed and latched position.
Each latch means 26, FIGS. 5-8, inclusive, comprises an upper latch element 50 and a lower latch element 51 having adjacent ends provided with a pivotal connection at 52. The upper end of latch element 50 has a pivotal connection at 54 to an anchor means 55 secured to closure frame member 37. In this example, anchor means 55 includes an inwardly extending slightly curved anchor body 56 provided with oppositely directed lugs 57 engageable with ribs 58 provided on frame member 37. Cooperable with anchor body 55 is a similarly curved anchor element 60 providing at one end pivotal connection 54 and positioned and secured to body 55 by a suitable nut and bolt assembly 61 extending through body 55 and engaging an elongated slot 62 in anchor element 60. Opposed surfaces of anchor body 55 and element 60 are serrated as at 63 to provide a mating interlock for fixedly positioning pivotal connection 54. Slot 62 and bolt assembly 61 provide a means for adjustment of the position of pivotal connection 54 for a purpose later described.
Lower latch member 51 has a pivotal connection 65 to a bottom anchor member 66 secured by suitable rivet means 67 to bottom flange 33 of roof frame member 30. Anchor member 66 has an inwardly directed downwardly inclined anchor portion 68 for positioning pivotal connection 65 inwardly of and below the plane of the opening defined by inwardly extending flange 33. The location of pivotal connection 65 may be spaced further below the plane of daylight opening 23 if desired depending upon the configuration of the frame members 30 and 37.
Upper latch member 50 includes a curved wall 70 and parallel side walls 71 which define a recess 72 within which may be received lower latch member 51 when the latch members are in collapsed or closed relation as shown in FIG. 6. Lower latch member 51 includes a longitudinally extending recess 73 for reducing weight of the latch member.
Crossbar 27 comprises a tube of lightweight metal formed in a generaly elliptical cross section with the major axis of the elliptical cross section lying generally parallel to the line between the axes of pivotal connections 54 and 52. As best seen in FIG. 8 the axis 75 of crossbar 27 is offset a distance A from the axis of pivotal connection 52, the offset being inwardly directed with respect to opening 23. As best shown in FIG. 8 and FIG. 11 the lower end portion of upper latch member 50 is provided with an enlarged metal portion 76. The portion 76 is provided with oppositely directed hollow cylindrical bosses 77, the inner boss 77 receiving thereover one end of crossbar 27. Crossbar 27 is secured by means of a screwbolt 78 which extends through the outer hollow boss 77 and has a head 79 seated on an internal shoulder in the enlarged portion 76. The end of screwbolt 78 extends through a bearing washer 80 against which is seated a compressible resilient washer 81, the opposite face of washer 81 being engaged by a nut 82 threaded on the end of bolt 78. Washer 81 is compressed by turning the bolt 78 so that the outer circumferential wall of the washer 81 is resiliently frictionally urged into engagement with the hollow tube forming the crossbar 27 and thereby frictionally securing the crossbar 27 to the latch means 26.
The outer boss 77 may be covered with suitable cap 84 having the same cross sectional configuration as crossbar 27, cap 84 being suitably frictionally secured on boss 77.
In operation of the latch means 20 and assuming that the closure member 21 is in closed position as shown in FIGS. 1, 2, and 6, the crossbar 27 may be grasped by the fingers of one hand and pulled inwardly of opening 23 to rotate lower latch member 51 about its anchor pivotal connection 65. It will be noted that in fully closed position as shown in FIG. 6 that the location of pivotal connection 65 is slightly beyond a line drawn between pivotal connection 52 and pivotal connection 54 to provide an off center toggle action which securely holds the closure member in closed position. As the crossbar is pulled about the anchor pivotal connection 65 the latch members 51 and 50 are separated from their nested relation, the closure member 21 is raised, and when the closure member 21 reaches its uppermost position, it will remain in such position by the frictional action of pivotal connections 52 and 65. Restriction on further movement of pivotal connection 52 beyond its selected offset position is provided by abutment at 87 of enlarged lower latch portion 76 with lower latch member 51. In closed nested relation as shown in FIG. 7 latch member 51 abuts against the inner surface of wall 70 of the upper latch member 50 to limit collapsed relation of the latch members.
When closure member 21 is to be closed, the crossbar 27 may be grasped and pulled inwardly and downwardly to swing the latch members about their pivotal connections 65 and 54 and 52 until the latch members are in closed and nested relation as shown in FIG. 6 and the closure member 21 closed and latched by the toggle relation of the pivotal connections.
It is important to note the relationship of the crossbar 27 when the closure member 21 is in closed position in respect to the plane of opening 23. In FIG. 6 crossbar 27 is located below the plane of opening 23 and outwardly of said opening, the specific location in FIG. 6 being below the edge portion of the wall 24. In this position, crossbar 27 is relatively close to the bottom surface of wall 24. The offset space A between pivotal connections 52 and the axis 75 of the crossbar spaces the crossbar below the bottom surface of wall 24 so that the fingers of the hand of an operator may readily reach between the crossbar and the bottom wall surface 92. In such position as shown in FIG. 2, crossbar 27 is substantially out of the way because of its closeness to the wall 24. Further, such closeness to the bottom surface 92 of wall 24 significantly reduces visual obstruction by the latch means of this invention.
In FIGS. 9 and 10, there is shown a roof structure 24' of substantially less thickness than roof structure 24. The latch means of this invention provides for ready adjustment of pivotal connection 54 in a downward direction by the adjustment means comprising anchor body 55 and anchor element 60. When the pivotal connection is lowered, as shown in FIGS. 9 and 10, the nested collapsed latch members 50 and 51 may be swung into almost parallel relationship with the wall 24'. Even in such relationship it will be apparent that the offsetting of the axis of handle 27 from pivotal connection 52 provides space for the convenient grasping of the crossbar by fingers of the hand of an operator when it is desired to open the closure member 21 or to move it into open latch position as shown in FIG. 9. It will be understood that such adjustment may be readily made by the operator by loosening the bolt and nut assembly 61 and then tightening the assembly so that the anchor pivotal connection 54 is fixed, such adjustment being in accordance with the operator's desire and convenience.
It will also be understood that the frame member 30 in the framed opening 28 may be made of relatively light weight aluminum extrusion material and while designed to be rigid, the closing pressures exerted on the lip 46 and the cross flange 39 may cause distortion or twisting or torquing of that portion of frame member 37 lying adjacent the latch means 26. Means to resist twisting of frame member 37 at this portion of the frame member may comprise a rigid block 95 of generally thickened enlarged J section. Block 95 is seated upon flange 33 and has a length which extends between the latch means 26. The upstanding portion 96 of the J shape extends along one surface of web 31 and in closed position of the closure member 21 is positioned between web 31 and web 38 of the closure frame member 37. The lower lip 46 is received within the recess 97 formed by the J shape. Thus, in the portion adjacent latches 26 twisting or torquing of frame member 30 is positively restricted.
To position Z section 29, which serves as a metal trim member for the opening 28, metal screws 99 may be provided between a lip of the Z section 29 and a relatively small flanged rib 100 extending from web 31.
In FIG. 4, it will be noted that when closure member 21 is in closed position, the lower lip 46 of closure frame member 37 is pressed against sealing material 34 and the outer seal element 43 is pressed against the top of web 33 as at 44. In an installation where closure member 21 and the vent opening 23 is arranged in a vertical wall, water will drain to the bottom edge of the opening and under some circumstances, may collect sufficiently to present leakage problems. To prevent accumulation of water between lip 42 and web 35 at the bottom portion of such a vertically disposed vent opening, seal 43 and lip 42, may be provided with weep holes.
It will be noted that the resilient material 34 also resists weather entry, provides insulation from metal-to-metal contact between the frame member 37 and frame 30 in closed position, and reduces or dampens vibrations which might cause rattling. The provision of gasket seal 34 on frame 30 around its periphery also improves the appearance of the closure means when it is in closed position. Seal 34 may be of suitable shape.
It may be desirable at selected spaced intervals around the periphery of the roof frame member 30 to provide spacer blocks similar to 95 in order to maintain uniform and accurate spacing between the closure means and the frame opening.
In FIGS. 12, 13 and 14, a modification of the operator means of this invention is shown as applied to a relatively thin section closure member 21' which is provided with frame means 37' around its periphery. In this embodiment the roof or wall 24' includes a peripheral frame member 30' having a cross-sectional shape similar to the frame member of the prior embodiment. A Z section trim member 29' is provided at the bottom edge of the framed opening 28'.
In the description of the embodiment of the invention shown in FIGS. 12-14 inclusive, differences from prior embodiment will be described and emphasized. Latch means 26' has a lower latch member 51' pivotally connected at 65' to an anchor element 66' carried by the inwardly extending flange 33' of the peripheral frame member 30'. In this example, the anchor element 66' is secured to a downwardly pre-bent portion 33'a to provide pre-stressing of flange 33' so that when closure forces act thereupon distortion of the flange 33' and the peripheral frame member 30' is reduced.
Latch member 51' is connected at 52' to the adjacent end of latch member 50' which has a pivotal connection 54' to a connector block 110. Connector block 110 has a threaded connection at 111 to a stud bolt 112 carried by the peripheral margin of closure member 21'. Connector block 110 has an extension portion 110a having a flat face 113 adapted to seat against one or both of ribs 58' of closure frame member 30'.
It will be apparent that the position of pivotal connection 54' may be adjusted vertically by the threaded connection of bolt 112 with connector block 110. To facilitate such adjustment, pivotal connection 54' is provided with a removable pivot pin 115 having a shank 116 receivable within a double or oppositely tapered hole 117 provided in block 110. Latch element 50' has spaced pin mounting lugs 118 to receive pin 115 and a portion of block 110 therebetween. A releasable lock ring 119 is carried by the shank of 116 of the pin for engagement with edges of one of the lugs 118 to retain pin 115 in position. Pin 115 is provided with a frustro conical head 120 of enlarged diameter to facilitate grasping by fingers of a hand so that the pin may be pulled axially and removed from assembly with latch member 50' and block 110. Pin 115 has an enlarged diameter shoulder 121 adapted to seat against adjacent surfaces of latch member 50' to limit insertion of pin 115.
Removal of pin 115 permits the latch member 50' to be released from its pivotal connection 54' and displaced away from the normal axis of the pivotal connection. Under this pin removal condition, it will be apparent that connector block 110 may be readily rotated to raise or lower the same and thereby change the vertical location of pivotal connection 54'. When the desired vertical location is achieved, the connector block and latch member 50' may be realigned and the pin 115 inserted through lugs 118 and through the bore 117 of block 110. In this manner the pivotal connection 54' may be vertically adjusted to permit the latch means 26' to assume a different position with respect to the roof 24' when in closed position.
It will be apparent that when the pivotal connection 54' is lowered in this manner that the face 113 of block 110 may cease to bear against the upper rib 58' but will always bear against the lower rib 58' of the peripheral frame member 30'. Such changing of the position of pivotal connection 54' also permits adjustment of the exerted closure force of the latch means 26' when the closure 21' is lowered and the latch means 26' moves into latched position.
The closure member structure shown in FIG. 12 is particularly adapted to a vent panel wherein relatively thin flat tempered glass is used and is subjected to some bending by bending of peripheral frame 30' in order to match the slightly curved contour of a vehicle van roof. The connector block 110, which is rigid and which is carried by the bolt 112, provides pressure engagement against the ribs 58' during certain portions of the opening and closing operation so that the peripheral frame 37' will not be subject to distortion due to stresses transmitted through the pivotal connections.
The latch means 26' is provided with crossbar 27' as in the prior embodiment so that spaced latch means 26' may be simultaneously operated with a simplified single motion of the offset crossbar. The latch members 50' and 51' .[.is.]. .Iadd.in.Iaddend.closed, collapsed position are in nested relation as in the prior embodiment. Lower latch member 51' is symmetrical with respect to its axis. The wall surfaces of latch member 50' limit travel of the latch means.
In the example the closure peripheral frame member 37' is provided with a seal element 130 of different configuration than the prior embodiment seal element 130 having a curved configuration terminating in a feather portion 131 to facilitate entry of the seal member into the opening defined by the frame member 30'. Seal element 130 may be secured in suitable manner by a wall 132 having interlocking engagement with the ribs 58'.
In FIG. 15, another modification of this invention is shown applied to an unframed closure member 21". It may be desirable to use a pane of plexiglass or other translucent material without the use of a metal frame such as closure frame 37, 37'. In such an installation, the latch means 26" is constructed similar to that described above except that the pivotal connection of the upper latch member at 54" is made to the lower end of a stud bolt 105 secured by suitable gasketed washer 106 to the member 21'. To provide sealing between the peripheral edge margins 107 of the member 21' and the framed member 30, a strip 108 of relatively thick resilient compressible gasket material may be bonded to the upper portion of frame member 30 including mechanical grasping by strip 108 of the outer edge of flange 32 and of the top portion of web 31.
In this example, anchor .[.piovotal.]. .Iadd.pivotal .Iaddend.connection 54" lies above the plane of opening 23 and may include connector block 110' and a releasable pivot pin 115'. Connector block 110' has a threaded bore engaged by stud bolt 105. Anchor pivotal connection 65" is preferably made by a downwardly extending anchor member as in the prior modification. The penetration of stud bolt 105 in the threaded bore may be decreased to lower pivot connection 54" so that latch means 26" may be moved into close proximity below and outwardly of the edge of the framed opening in wall 24.
In the examples of the invention described above, it is important to note that one of the pivotal connections of the latch means is vertically adjustable in order to vary the position of the latch means in its fully closed position with respect to the roof or wall. Even when the pivotal connection 52 of the latch means is in close proximity to the interior surface of the roof, the offset axis of the crossbar 27 provides sufficient room for insertion of a finger to assure proper grasping of the crossbar for operation of the latch means to raise the closure member and to draw the closure member into snug closed relation with respect to the framed opening. The adjustment of the pivotal connections 54, 54' and 54" also provides for adjustment of the closing force which will be exerted on the peripheral seals of the closure member so that an optimum closing force may be selected and used. A weather tight seal is thereby provided with an optimum minimum force being applied to the seals to effect such a weather tight seal.
The adjustment of the pivotal connection also permits the latch means to be adjusted in closed position relative to the interior surface of the wall or roof so that a preferred position of the latch means and crossbar may be obtained.
It will be understood that various modifications and changes may be made in the construction and operation of the means for opening, closing and latching a closure member for a vent opening all of which may come within the spirit of this invention and such changes and modifications coming within the scope of the appended claims are embraced thereby.
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A device for opening, closing and latching a roof vent closure member for vehicles and including an upper latch member pivotally connected to the closure member, a lower latch member pivotally connected to the frame defining the opening in the roof, said upper and lower latch members being pivotally interconnected and a bar connected to said upper latch member in offset relation to its pivotal connection to the lower latch member for actuating the device. The pivotal connections of the latch members are arranged to provide a toggle or off center relationship in closed position of the closure member. The latch members and pivotal connections thereof are so arranged to permit the crossbar to be positioned below and outwardly of the frame defining the roof opening to provide headroom, non-obstructed vision, and aesthetic appearance. The device includes means for adjusting the positions of certain pivotal axes of said pivotal interconnections to adjust the latch members to roof or wall structures of different depth.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a division application based on U.S. application Ser. No. 13/241,165 filed on Sep. 22, 2011.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a functional polyurethane prepolymer, a method of preparing polyurethane by using the functional polyurethane prepolymer, and an application method thereof, in particular to a functional polyurethane prepolymer prepared by a non-isocyanate route, a method of preparing polyurethane by a using the functional polyurethane prepolymer, and an application method thereof.
[0004] 2. Description of Related Art
[0005] Polyurethane (PU) is a common polymer material widely used as a sports cushion material, an elastomer material, an adhesive material, a waterproof material or a coating material.
[0006] In a conventional PU preparation process, the PU is synthesized by using isocyanates (such as diisocyanates and polyisocyanates) and polyols (such as diols or polyhydroxy polyols with high functionality) as major raw materials, but the manufacturing process of this sort usually requires phosgene which is a severely toxic pollutant. If the phosgene is leaked accidentally during the manufacturing process, the phosgene will pose an immediate threat to our environment and jeopardize our health such as causing pulmonary edema, and the manufacturing process itself will lead to a certain degree of risk. Therefore, scientists attempt to use non-isocyanates routes (which use absolutely no isocyanates at all) to manufacture polyurethane (PU).
[0007] In 1993, Takeshi Endo proposed a PU manufacturing method without using any diisocyanates, wherein five-membered cyclic carbonates (Bis(cyclic carbonate)s) and primary amines are reacted at room temperature to produce a high yield of β-position hydroxyl PU (2-Hydroxyethylurethane), and the reaction is represented by the following chemical equation:
[0000]
[0008] Typically, the starting material (cyclic carbonate) of hydroxyl PU is prepared by a nucleophilic ring opening reaction of oxirane and carbon dioxide. As indicated in past literatures, cyclic carbonate is mainly prepared by a reaction of oxirane, carbon dioxide, and a catalyst at high pressure, and the common catalysts include amine, phosphine, quaternary ammonium salt, antimony compound, porpyrin and transition metal complex, and the manufacturing conditions and process involve a high level of difficulty. Until recent years, the ring opening reaction of oxirane and carbon dioxide taken place at normal pressure (1 atmosphere) was developed.
[0009] Professor Takeshi Endo, et al. further published a preparation of hydroxyl PU by using di-functional amines and di-functional cyclic carbonates, and subsequent research reports related to the ring opening reaction of cyclic carbonates provided the related reaction conditions, and specifically pointed out that the ring opening reaction has a high chemoselectivity, and will not be affected by existing water, alcohols, or esters, so that the cyclic carbonate can be reacted with a compound containing a primary amine under appropriate reaction conditions for a ring-opening polymerization, and the reaction is represented by the following chemical equations:
[0000]
[0010] However, the aforementioned method is developed for the PU prepolymer with an amino functional group at an end and having a maximum average molecular weight falling within the range from 5000 g/mole to 8000 g/mole. The ring opening reaction process of the aforementioned method requires a time (20 hours or more), and this product cannot be applied for a coating application directly and effectively.
SUMMARY OF THE INVENTION
[0011] The present invention provides a method of preparing a polyurethane (PU) prepolymer, and the method does not use any conventional isocyanate as a raw material, and the manufacturing process does not require the use of phosgene. Epoxy resin and carbon dioxide are used as major raw materials for the preparation of the macromolecular polyurethane prepolymer.
[0012] The preparation method of the present invention comprises the following steps:
[0013] (1) Material mixing: An epoxy resin and a catalyst are mixed uniformly until the epoxy resin is dissolved completely to form a mixed raw material; and
[0014] (2) Thermal reflux: Carbon dioxide gas is introduced into the mixed raw material, and a thermal reflux is performed at a high temperature for a predetermined time to form a bis-(cyclic carbonate) containing compound (BCC).
[0015] The aforementioned reaction is represented by the following chemical equations:
[0000]
[0000] wherein R is
[0000]
[0016] (3) Ring-opening polymerization: After a bis-(cyclic carbonate) containing compound (BCC) and a di-amine compound are mixed uniformly, and the ring-opening polymerization is represented by the following chemical equations:
[0000]
[0017] (4) The amino-terminated PU prepolymer (obtained from the above reaction) is mixed and reacted with a di-acrylate compound (AHM) via a Michael to obtain an UV curable polyurethane, and the Michael addition is represented by the following chemical
[0000]
[0018] The present invention further provides a method of preparing polyurethane comprising the following steps:
(1) Material mixing: An epoxy resin and a first catalyst are mixed uniformly until the epoxy resin is dissolved completely to form a mixed raw material; (2) Thermal reflux: Carbon dioxide gas is introduced into the mixed raw material, and a thermal reflux is performed at a high temperature for a predetermined time to form a bis-cyclic carbonate-containing oligomer; (3) Microwave reaction: The bis-cyclic carbonate-containing oligomer is mixed with a second catalyst uniformly, and then a ring-opening polymerization with one or more di-amine compound is performed to form a PU prepolymer containing an amino group at an end; and (4) Michael reaction: The aforementioned PU prepolymer with mixed with a third catalyst uniformly, and then a compound with an acrylic functional group is added to perform a Michael reaction at a low temperature to form an UV curable polyurethane.
[0023] The present invention further provides an application method of polyurethane, wherein the polyurethane is produced by using an epoxy resin, carbon dioxide and a polyamine compound as major raw materials, and the application method comprises the following steps:
(1) Dipping: An UV curable PU (UV-PU) material and a photoinitiator are mixed uniformly to form a PU raw material solution, and a fabric is placed into the PU raw material solution for pressure suction. Make sure the fabric absorbs a sufficient amount of the PU raw material. (2) Photoreaction: The treated fabric is placed into a medium pressure mercury lamp UV irradiation is provided for fixing the PU raw material solution onto a surface of the fabric.
[0026] The method of the present invention does not require the conventional use of isocyanates and polyols as raw materials for preparing PU, and epoxy resin and carbon dioxide, and then di-amine oligomer are used as starting raw materials and polyamines are added to prepare the PU prepolymer, and the PU prepolymer produced by this method can be further used for synthesizing an UV curable PU (UV-PU) in a simple and convenient manner, and the UV-PU can be further coated onto a fabric surface, and the fabrics with UV-cured PU surface treatment is adopted to form a washing resisting and long-lasting hydrophilic or hydrophobic PU treated fabrics.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The invention, as well as its many advantages, may be further understood by the following detailed description and drawings in which:
[0028] FIG. 1A shows a Fourier infrared spectrum of polypropylene glycol diglycidyl ether (PPG-DGE) used in a first preferred embodiment of the present invention;
[0029] FIG. 1B shows a Fourier infrared spectrum of PPG-type cyclic carbonates formed in the first preferred embodiment of the present invention;
[0030] FIG. 2 shows a Fourier infrared spectrum of polyurethane (PU) formed in the first preferred embodiment of the present invention;
[0031] FIG. 3 is a SEM photo of the produced UV curable polyurethane coated onto surfaces of fabric fibers and washed by water for 30 times in accordance with the first preferred embodiment of the present invention;
[0032] FIG. 4A shows a Fourier infrared spectrum of bisphenol A epoxy resin used in a second preferred embodiment of the present invention;
[0033] FIG. 4B shows a Fourier infrared spectrum of bis(cyclic carbonates) (BCC) formed in the second preferred embodiment of the present invention;
[0034] FIG. 5 shows a 1 H NMR spectrum of bisphenol A epoxy resin used in the second preferred embodiment of the present invention;
[0035] FIG. 6A shows a 1 H NMR spectrum of bis(cyclic carbonates) (BCC) formed in the second preferred embodiment of the present invention;
[0036] FIG. 6B shows a 13 C NMR spectrum of bis(cyclic carbonates) (BCC) formed in the second preferred embodiment of the present invention; spectrum;
[0037] FIG. 7 is a Fourier infrared spectrum of polyurethane (PU) formed in the second preferred embodiment of the present invention; and
[0038] FIG. 8 shows a SEM photo of the produced UV cross-linking polyurethane coated onto surfaces of fabric fibers, processed by a UV light bridge, and washed by water for 30 times in accordance with the second preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0039] In the first preferred embodiment, the polyurethane (PU) prepolymer is prepared by an epoxy resin which is polypropylene glycol diglycidyl ether (PPG-DGE), and the aforementioned polyurethane prepolymer is used for manufacturing polyurethane (PU) and UV curable polyurethane (UV-PU), and the UV curable polyurethane (UV-PU) is further applied as a water-resisting material.
[0040] (1) Method of Preparing Polyurethane Prepolymer:
[0041] In this preferred embodiment, the polyurethane prepolymer is bis(cyclic carbonate) which is a PPG-type cyclic carbonate, the epoxy resin is polypropylene glycol diglycidyl ether (PPG-DGE), and the catalyst is lithium bromide (LiBr), and the method of preparing a PU prepolymer comprises the following steps:
[0042] (S11) Material mixing: PPG-DGE (5 moles) and lithium bromide (5 mole percents) are mixed uniformly until the PPG-DGE is dissolved completely to form a mixed raw material; and
[0043] (S12) Thermal reflux: Carbon dioxide gas is introduced into the mixed raw material, and a thermal reflux is performed at the pressure of one atmosphere and a temperature of 100° C. for 24 hours to form a bis(cyclic carbonate) product.
[0044] In this preferred embodiment, a large quantity of deionized water and ethyl acetate are used for rinsing the bis(cyclic carbonates) product to remove remained catalysts and achieve the purification effect, so as to obtain a highly pure transparent colorless bis(cyclic carbonate) liquid.
[0045] With reference to FIGS. 1A and 1B , a Fourier-transformed infrared spectroscopy is used for detecting and tracing the elimination state of the epoxy functional group (910 cm −1 ) and the formation state of the cyclic carbonate functional group (1800 cm −1 ). The Fourier infrared spectra show that the epoxy functional group is fully converted into the cyclic carbonate functional group.
[0046] (2) Method of Preparing PU Prepolymer Containing an Amino Group at an End:
[0047] The bis(cyclic carbonates) product produced by the aforementioned method can be used for manufacturing a PU prepolymer containing an amino group at an end, and the method comprises the following steps:
[0048] (S21) Microwave treatment: The aforementioned bis(cyclic carbonate) product (0.1 mole), lithium bromide (5 mole percents) and Jeffamine compound (a di-amine D-2000, 0.15 mole) are mixed uniformly, and then a microwave reactor with the power of 100 W is provided for performing a ring-opening polymerization for half an hour to form a PU prepolymer containing an amino group at an end.
[0049] With reference to FIG. 2 for a Fourier-transformed infrared spectrum of PU obtained in accordance with the preparation method of the present invention, a formation of an amino ester functional group is observed at the wavelength of 1720 cm −1 , indicating that the cyclic carbonate functional group (1800 cm −1 ) of the cyclic carbonate functional group in this step will disappear with the reaction time, and will be converted into an amino ester functional group (1720 cm −1 ).
[0050] In the microwave treatment step (S21), the Jeffamine compound is a polyamine compound well known to those ordinarily skilled in the art, and the compound used in this preferred embodiment is one selected from the group of hydrophilic aliphatic diamines (such as 1,4-butanediol bis-3-aminopropyl ether), ethylene diamines, aliphatic diamines (such as 1,12-diaminododecane), aromatic diamines (such as m-xylyene diamine) or a hydrophobic diamine compounds, such as polydimethylsiloxane (PDMS) diamine.
[0051] In addition, the microwave treatment step (S21) further selectively adds a solvent for a dilution to reduce the viscosity of the reactants, wherein the solvent can be ethyl lactate (EL), and the quantity of EL in this preferred embodiment is equal to 10 mL, and the Fourier infrared spectrum of the PU containing an amino group at an end after the reaction takes place is the same as that of the one added with a catalyst.
[0052] Further, microwave intensity used in the microwave treatment step (S21) can be adjusted to a range from 15 W to 150 W, and the microwave treatment time can be adjusted to a range from 0.5 hour to 2 hours.
[0053] (3) UV Curable Polyurethane (UV-PU):
[0054] The PU prepolymer formed in accordance with the aforementioned method can be further used for manufacturing an UV-PU, and the method comprises the following steps:
[0055] (S31) Michael reaction: The aforementioned PU prepolymer and a catalyst (triethyl amine, TEA) (5 mole percents) are mixed uniformly, and then 20 mL of ethyl acetate is added, and the mixed materials are dropped slowly into 0.2 mole of a compound containing diacrylate at 0° C. (or in an ice bath), and the Michael reaction is performed in the ice both for 24 hours to remove the catalyst TEA and ethyl acetate to produce an UV-PU material.
[0056] In the Michael reaction step (S31), the ethyl acetate solvent may not be added for the reaction.
[0057] (4) Application of UV-PU:
[0058] The UV-PU material obtained in accordance with the method of the present invention can be used for forming a mesh bonding on a fabric surface and can be embedded into the surface of fiber bundles easily, so that the hydrophilic polymer in the fabric will not be changed or lost easily by rinsing, and the original hydrophilic property of the hydrophilic resin can be maintained, so as to obtain the long-lasting rinsing-resisting super-absorbent fabric, and the application method comprises the following steps:
[0059] Dipping: The aforementioned UV-PU material is diluted by ethyl acetate (EA) to the concentration of 1˜10 wt %, and 5 phr of photoinitiator benzoin alkyl ether (1173) is added to form a UV-PU solution, and different fabrics (PET) are placed into the aforementioned UV-PU solution for pressure suction. After the fabric sufficiently absorbs the solution, and a fabric is placed into the PU raw material solution for pressure suction and make sure that the fabric absorbs a sufficient amount of PU raw material.
[0060] Photoreaction: The aforementioned fabric is placed into a medium pressure mercury lamp UV irradiation for fixing the PU raw material solution onto the treated fabric to form a double-bond methyl acrylic functional group in of the UV-PU material, and a radical cross-linking reaction is performed to produce a mesh bonding, and the UV-PU material can be embedded into a surface of the fiber bundles easily, so that the hydrophilic polymer in the fabric will not be damaged or lost easily by rinsing, and the original hydrophilic property of the hydrophilic resin can be maintained, so as to obtain the long-lasting washing-resisting super-absorbent fabric.
[0061] With reference to FIG. 3 for a SEM photo of the produced UV-PU solution coated onto surfaces of fabric fibers and washed by water for 30 times in accordance with the first preferred embodiment of the present invention, the photo shows that the high-density mesh bonding formed by the UV-PU material on the fabric surface is not damaged or lost by rinsing, and the original hydrophilic property of the hydrophilic resin is maintained.
[0062] In this preferred embodiment, the photoinitiator is a photosensitizing agent such as benzophenone (BP) or a reactive diluent with acrylic double bonds is added into the UV-PU solution to increase the concentration of the acrylic double bonds, so as to enhance the crosslink density of the UV-PU material.
[0063] In the second preferred embodiment, bisphenol A epoxy resin such as diglycidyl ether bisphenol A (DGEBA) is used as the epoxy resin for preparing the polyurethane prepolymer, and the aforementioned polyurethane prepolymer is used for manufacturing polyurethane (PU) and UV cross-linking polyurethane (UV-PU), and the UV cross-linking polyurethane (UV-PU) is further applied as a water-resisting coating material.
[0064] (1) Method of Preparing Polyurethane Prepolymer:
[0065] In this preferred embodiment, the bis(cyclic carbonates) (BCC) so formed is a polyurethane prepolymer, the epoxy resin is di-glycidyl ether of bisphenol A (DGEBA), and the catalyst is lithium bromide (LiBr). The method of preparing a polyurethane prepolymer comprises the following steps:
[0066] (S11) Material mixing: DGEBA (5 moles) and lithium bromide (5 mole percents) are mixed uniformly until the DGEBA is dissolved completely to form a mixed raw material; and
[0067] (S12) Thermal reflux: Carbon dioxide gas is introduced into the mixed raw material, and a thermal reflux is performed at a pressure of one atmosphere and a temperature of 100° C. for 24 hours to form a BCC product (or oligomer).
[0068] The BCC product obtained in accordance with this preferred embodiment can be rinsed by a large quantity of deionized water to remove remained catalyst and solvent to achieve the purification effect, and then baked and dried to a fine pure white BCC powder.
[0069] With reference to FIGS. 4A , 4 B, 5 , 6 A and 6 B for Fourier infrared spectra that detect the elimination state of the epoxy functional group (910 cm −1 ) and the formation state of the cyclic carbonate functional group (1800 cm −1 ), the Fourier infrared spectra show that the epoxy functional group is sufficiently converted into the cyclic carbonate functional group. In addition, a nuclear magnetic resonance (NMR) is used for performing a structure analysis to confirm the molecular structure of the BCC product produced in according to the procedure of this preferred embodiment.
[0070] (2) Method of Preparing a PU Prepolymer Containing an Amino Group at an End:
[0071] The BBC product produced in accordance with the aforementioned method can be used for preparing a PU prepolymer, and the preparation method comprises the following steps:
[0072] (S21) Microwave treatment: The aforementioned BBC product (0.1 mole), lithium bromide (5 mole percents) and aliphatic amine which is Jeffamine D-2000 (0.15 mole) are mixed uniformly, and a microwave reactor with the power of 100 W is provided for performing a ring-opening polymerization for half an hour to form a PU prepolymer containing an amino group at an end.
[0073] With reference to FIG. 7 for a Fourier-transformed infrared spectrum of PU obtained by this method, a formation of an amino ester functional group is observed at the wavelength of 1720 cm −1 . In this step, the cyclic carbonate functional group (1800 cm −1 ) in the cyclic carbonate functional group disappears with the reaction time and is converted into an amino ester functional group (1720 cm −1 ). The PU prepolymer formed by this method has a molecular weight of 20000 g/mole or above, which can be used more easily in the following applications.
[0074] In the microwave treatment step (S21), a solvent can be added to dilute the solution and reduce the viscosity of the reactants, wherein the solvent is ethyl lactate (EL) or ethyl acetate (EA), and the quantity of the solvent used in this preferred embodiment is equal to 10 mL, and the Fourier infrared spectrum of the produced PU prepolymer containing an amino group at an end shows the same result with the one added with a catalyst.
[0075] (3) Method of Preparing UV Curable Polyurethane (UV-PU):
[0076] The PU prepolymer produced according to the aforementioned method can be used for preparing the UV-PU, and the preparation method comprises the following steps:
[0077] (S31) Michael reaction: The aforementioned PU prepolymer and a catalyst (triethyl amine, TEA) (5 mole percents) are mixed uniformly, and then 20 mL of ethyl acetate is added, and 0.2 mole of a compound containing diacrylate is dropped into the solution slowly at 0° C. (or in an ice bath), and then the Michael reaction is performed in the ice bath for 24 hours to remove the catalyst TEA and ethyl acetate to produce an UV-PU material.
[0078] In the Michael reaction step (S31), the solvent ethyl acetate solvent may not be used in the reaction.
[0079] In this preferred embodiment, the compound containing diacrylate is 3-Acryloyloxy-2-hydroxypropyl methacrylate.
[0080] (4) Application of UV-PU:
[0081] The UV-PU material obtained according to the method of the present invention method can be used to form a mesh bonding on a fabric surface and can be embedded into a surface of fiber bundles successfully, so that the hydrophilic polymer in the fabric will not be changed or lost easily by rinsing, and the original hydrophilic property of the hydrophilic resin can be maintained, the long-lasting washing-resisting super-absorbent fabric. The application method comprises the following steps:
[0082] Dipping: The aforementioned UV-PU material is diluted by ethyl acetate (EA) to a concentration of 1˜10 wt %, and then 5 phr of photoinitiator such as benzoin alkyl ether, (1173) is asked to form a UV-PU solution, and various different fabrics (PET, cotton) are placed into the UV-PU solution for pressure suction and make sure that the fabric absorbs a sufficient amount of PU raw material.
[0083] Photoreaction: The aforementioned fabric is placed into a medium pressure mercury lamp UV irradiation for fixing the PU raw material solution onto the treated fabric to form a double-bond methyl acrylic functional group in of the UV-PU material, is used for performing a radical cross-linking reaction of the double-bond methyl acrylic functional group in the UV-PU material to produce a mesh bonding, and the UV-PU material can be embedded into the surface of fiber bundles successfully, so that the hydrophilic polymer in the fabric will not be damaged or lost easily by rinsing, and the original hydrophilic property of the hydrophilic resin can be maintained, so as to obtain the long-acting washing-resisting super-absorbent fabric.
[0084] With reference to FIG. 8 for a SEM photo of the produced UV cross-linking polyurethane coated onto surfaces of fabric fibers and washed by water for 30 times in accordance with the second preferred embodiment of the present invention, the SEM photo shows that the high-density mesh bonding of the UV-PU material formed on the fabric surface is not damaged or lost by rinsing, and the original hydrophilic property of the hydrophilic resin is maintained.
[0085] In this preferred embodiment, the photoinitiator is a photosensitizing agent such as benzophenone (BP) or a reactive diluent with acrylic double bonds is added into the UV-PU solution to improve the crosslink density of the UV-PU material.
[0086] In this preferred embodiment, the epoxy resin is bisphenol A epoxy resin or di-glycidyl ether of bisphenol A (DGEBA). However, the invention is not limited to these substances only, but any equivalent epoxy resin such as Epoxy-128, Epoxy-506, Epoxy-904, aliphatic epoxy resin, PPG-DGE, PEG-DGE and any combination of the above can be used in the present invention as well.
[0087] In summation of the description above, the present invention provides a novel process for manufacturing the polyurethane prepolymer and the UV curable polyurethane without using isocyanates and polyols as raw materials, so as to avoid the use of harmful substance such as phosgene and reduce the risk of harming our environment. In addition, the method of the present invention is simple and convenient and requires no specific ambient conditions. Compared with the conventional preparation methods, the present invention has the advantages of protecting the environmental and achieving the energy-saving and carbon reduction effects.
[0088] Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.
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A method of preparing polyurethane prepolymer does not require using a toxic isocyanate monomer (manufactured by harmful phosgene) as a raw material. Epoxy resin and carbon dioxide are used as major raw materials to form cyclic carbonates to be reacted with a functional group oligomer, and then amino groups in a hydrophilic (ether group) or hydrophobic (siloxane group) diamine polymer are used for performing a ring-opening polymerization, and the microwave irradiation is used in the ring-opening polymerization to efficiently synthesize the amino-terminated PU prepolymer, and then an acrylic group at an end is added to manufacture an UV cross-linking PU (UV-PU) oligomer which can be coated onto a fabric surface, and the fabric is dried by UV radiation for a surface treatment to form a washing-resisted long lasting hydrophilic or hydrophobic PU fabric.
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BACKGROUND OF THE INVENTION
The invention relates to the manufacture of articles from a thermoplastic of polyester or polyamide type, preferably of polyethylene terephthalate, the articles being formed from an element which consists of an edge part which surrounds a body in an arrangement in which the latter is sunk relative to the edge part. The element is formed from a blank of mainly amorphous material or from a material having a crystallinity of less than 10%. The blank consists, for example, of a flat plate, a blank shell or the like. The body or parts thereof are shaped by stretching the blank until that material flows which is located within the material sections of the blank, which form the edge part in the element, the material stretched up to flowing in the body assuming a crystallinity of between 10% and 25%, whilst the crystallinity in the material in the edge part and in the unstretched parts retains its original value of less than 10%. The edge part is severed from the body, the latter being elongated in the axial direction by a number of drawing steps, whilst the dimensions of the body at right angles thereto are reduced at the same time. The body of the element of the drawn part is reshaped by a blow-moulding process to give the article.
In the manufacture of products from thermoplastics, the starting material is in most cases a virtually flat blank. Either an end product is formed here substantially in one deformation step, or a premoulding is formed for later reshaping to give the end product. The shaping of the blank is effected, according to methods known at present, either by the blow-moulding process or by the thermo-forming process. In the blow-moulding process, thick sections are as a rule obtained in the bottom. In the thermo-forming process, either so-called negative thermo-forming or so-called positive thermo-forming is used. In the negative thermo-forming process, a thin bottom is obtained, whilst a thick bottom is obtained in the positive thermo-forming process.
In negative thermo-forming, a warm sheet or a warm film is placed over cavities, after which the material of the film or the sheet is pressed and sucked into the cavities by external pressure and internal reduced pressure. This has the result that the material is stretched and becomes thin, when it is sucked into the particular cavities. If the cavity is a cup, a thin stretched bottom and a wall thickness increasing in the direction of the edge of the cup are obtained.
In positive thermo-forming the cup mould forms a projecting body and the material of the film or sheet is pressed and sucked over this projecting body. This has the result that the material on the upper part of the projecting body, that is to say the bottom of the cup, remains thick and essentially unstretched, whilst the thickness of the material decreases towards the edge of the cup.
To obtain an adequate material thickness in the bottom part of the cup in negative thermo-forming, a sufficient thickness in the starting material must be chosen. To obtain an adequate thickness in the edge zone of the cup by positive thermo-forming, which is necessary for stability of the cup, a sufficient thickness of starting material must likewise be chosen. In negative thermo-forming, the material zones between the shaped cups remain uninfluenced and are subsequently severed, after the manufacture of the actual cups. In positive thermo-forming, the material between the cups is drawn into recesses and severed from the cups formed. In positive thermo-forming, cup bottoms are thus obtained which have substantially the same thickness as the starting material. Both forming processes require an unnecessarily high consumption of material, which is of economic importance in the mass production of articles.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method which eliminates certain disadvantages connected with the technology hitherto known.
The invention is suitable preferably for the manufacture of articles from thermoplastics of the polyester or polyamide type. Examples of such materials are polyethylene terephthalate, polyhexamethyleneadipamide, polycaprolactam, polyhexamethylene-sebacamide, polyethylene 2,6- and 1,5-naphthalate, polytetramethylene 1,2-dihydroxybenzoate and copolymers of ethylene terephthalate, ethylene isophthalate and similar polymers. The description of the invention below relates mainly to polyethylene terephthalate, called PET in the further text, but the invention is not restricted exclusively to the use of either this material or other materials already mentioned; instead, it is also suitable for many other thermoplastics.
For a better understanding of the existing problem and of the invention, several characteristic properties of the polyester polyethylene terephthalate are described below. From the literature, for example Properties of Polymers, by D. W. van Krevelen, Elsevier Scientific Publishing Company, 1976, it is known that the properties of the material change when amorphous polyethylene terephthalate is oriented. Some of these changes are shown in the diagrams, FIGS. 14.3 and 14.4 on pages 317 and 319 in the book "Properties of Polymers". The symbols used in the discussion below correspond to the symbols in the said book.
PET, like many other thermoplastics, can be oriented by stretching the material. Normally this stretching takes place at a temperature above the glass transition temperature Tg of the material. The strength properties of the material are improved by orienting. The literature shows that, in the case of the thermoplastic PET, an increase in the stretching ratio Λ, that is to say the ratio of the length of the stretched material and the length of the unstretched material, also leads to an increase in the improvement of the material properties. When the stretching ratio Λ is increased from about 2 to a little more than 3, particularly large changes in the material properties are obtained. The strength in the direction of orientation is here markedly improved, whilst at the same time the density ρ and likewise the crystallinity Xc rises and the glass transition temperature Tg is raised. It can be seen from the diagram on page 317 that, after stretching, with Λ assuming the value of 3.1, the material withstands a force per unit area, which corresponds to σ=10, coupled with a very small elongation, whilst the elongation at Λ=2.8 is substantially larger. In the further test, the term "step" is sometimes used to designate orienting which is obtained by stretching, or a reduction in thickness by at least about 3 times, and which leads to the marked improvements of the material properties, indicated above.
The diagrams quoted above show changes which are obtained on mono-axial orientation of the material. In biaxial orientation, similar effects are obtained in both directions of orientation. Orientation is carried out as a rule by successive stretchings.
Improved material properties, corresponding to those which are obtained by the "step" defined above, are also obtained if an amorphous material is stretched until it flows and, before flowing, the material is at a temperature which is below the glass transition temperature Tg. In a rod being drawn, a reduction of the diameter of about 3 times results in the flow zone. On drawing, the flow zone is continuously displaced into the amorphous material, whilst at the same time the material, which has already undergone the state of flowing, absorbs the tensile forces of the test rod without an additional permanent stretching.
According to the invention, an element is produced which consists of an edge part and a cup part, starting from a substantially flat blank of amorphous material or having a crystallinity of less than 10%. The material in annular sections in the blank is transformed into the state of flow by a drawing process. The cup part is formed in this way. In certain applications, the ratio between the radial and the axial expansion of the cup is such that production of the beaker in a single drawing step is not possible. According to the invention, the desired ratios are obtained by a number of redrawing steps of the cup, the diameter of the cup being reduced in each redrawing step, whilst the thickness of the material remains more or less unchanged.
The cup part of the element or the drawn cup is reshaped by a blow-moulding process to give the article.
According to the invention, an element is obtained which consists of an edge part and a cup part, the material preferably being of more or less uniform thickness and orientation in the entire bottom of the cup part (cup). In a certain embodiment of the invention, the material in the bottom part of the cup moreover consists completely or partially of material of the same thickness as that of the material of the wall. The remaining sections of material have the thickness and material properties of the material. In certain applications, the bottom is more or less completely flat, whilst in other applications the bottom consists of parts which are axially displaced relative to the axis of the cup. In this case, in certain embodiments, annular edge sections are formed adjoining the lower edge of the wall, whilst in other embodiments central bottom sections are displaced further away from the upper opening edge of the element.
The element consists of an edge part which surrounds a body which is sunk relative to the edge part. The material in the edge part is mainly amorphous or has a crystallinity of less than 10%. The body has a wall part and a bottom part. The wall part consists of material which has been drawn at a temperature below the glass transition temperature Tg, until flow sets in, and in which the crystallinity is between 10% and 25%. In the basic design of the element, the bottom consists of mainly amorphous material or of material having a crystallinity of less than 10%. In embodiments of the invention, the bottom consists, as desired, of material which has been drawn at a temperature below the glass transition temperature Tg and at a crystallinity between 10% and 25%, until flow sets in, that is to say of a material having properties which mainly are identical to the material properties of the wall part of the element, or of material sections which have been drawn until flow sets in and which alternate with material sections of mainly amorphous material or material having a crystallinity of less than 10%. In certain embodiments, the material zones already mentioned are displaced in the axial direction relative to the lower edge of the wall part.
During the production of an element, a mainly flat blank of thermoplastic, having a crystallinity of less than 10%, is clamped in at a temperature below the glass transition temperature Tg between counter-holders, so that a zone is formed which is completely surrounded by the clamped-in material sections. A press device the contact surface of which is smaller than the surface area of the zone, is applied against this zone. Thus, a closed strip-like material zone is formed between the clamped-in material sections of the blank and that part of the zone which is in contact with the press device. Subsequently, a drive mechanism shifts the press device relative to the counter-holder, while the press device remains in contact with the zone. The material in the strip-like zone is thus stretched in such a way that flow of the material occurs, the material being monoaxially oriented, whilst at the same time the thickness of the material is reduced by about 3 times in the case of PET. The wall part of the element is formed during the stretching process.
Since the circumference of the contact surface of the press device is smaller than the inner circumference of the clamping devices, the material which adjoins the edge of the press device is subjected to the greatest stress, for which reason the flow of the material normally starts at this point. The effect thus resulting is further reinforced by the fact that the transition from the contact surface of the press device to the side walls of the press device is made relatively sharp-edged. When flow has set in, the zone of flow of the material is gradually shifted in the direction of the clamping devices. In certain application examples, the press step is interrupted when the flow zone has reached the press devices. In other application examples, the press step continues, renewed flowing of the material taking place adjoining the edges of the press device and being displaced from these zones towards the center of the material. When all the material which is in contact with the contact surface of the press device has undergone flow, that material between the clamping devices which is located next to the inner circumference of the clamping devices is utilized for a further drawing step in certain application examples. To make this possible, a somewhat elevated temperature in this material is normally required. The starting temperature, however, is still below the glass transition temperature Tg.
In certain application examples, accelerated cooling of the drawn material is necessary. In this case, the press device is preferably provided with a cooling device which is arranged in such a way that the zones of the material, which flow during drawing of the material, are in contact with the cooling device.
In certain applications, the flow of the material is caused to start adjoining the clamping devices. This is accomplished by providing the clamping devices with heating devices which raise the temperature of those material sections where flow is to start. The temperature in the material, however, is still below the glass transition temperature Tg of the material. When flow has set in, this continues in the direction of the contact surface of the press device and, in some cases which may occur, it continues past the transition from the side walls to the contact surface of the press device. To ensure that the clamping devices retain the blank in the future edge sections of the element, the clamping devices are as a rule provided with cooling devices.
The concept of the invention also comprises the possibility that, by a number of drawing steps which are arranged one after the other, both in the wall part and in the bottom part of the body, material sections are obtained which alternately consist of material sections which have been drawn until flow sets in and have in this way been given a reduced wall thickness, and undrawn material sections which have retained their wall thickness. In material sections located in the bottom part of the body, a displacement of the material in the axial direction of the body also takes place in certain application examples in conjunction with the drawing step.
The edge part is removed from the element formed and the element is reshaped by a number of drawing steps. These drawing steps take place at a temperature below the glass transition temperature Tg and effect a reduction of the diameter of the cup, whilst the length of the body is extended at the same time in the axial direction. The drawing step effects exclusively a redistribution of the material without flow setting in.
The cup formed after the end of the drawing step has an opening at one end, whilst it has a bottom part at the other end. Depending on the manner in which the element has been shaped, the bottom part consists wholly or partially of amorphous material or of unoriented material. In the first-mentioned case, the bottom part thus retains the thickness of the starting material in the amorphous zone or in the amorphous zones. The amorphous material is suitable for use as a fixing material for welding additional parts to the cup. This requirement will be present, for example, when the cup is used as a container and the bottom part of the cup simultaneously represents the bottom part of the container. In this case, it is advantageous to weld an external foot to the container. The cup shaped in the manner described possesses an opening part which, if appropriate after reworking, is preferably expanded in such a way that a beaded edge results, the stability of the beaded edge being increased by heating up to the maximum crystallisation temperature of the material. The beaded edge is thus outstandingly suitable for fitting, for example, a loose lid of a suitable material, for example metal, by crimping.
In another application example, the drawing step at the cup is interrupted so that parts of the cup have a reduced diameter compared with the initial diameter. By removing the bottom from this part of smaller diameter, expanding the edge formed and stabilising the opening which has been formed in the manner described in the preceding section, a mouth part is obtained which is suitable for fitting, for example, a closure or a crown cap. The other still open part of the cup is closed, for example, by an end disc, in a manner similar to that already described.
In the blow-moulding process, the starting point is either a cup which has been severed in the normal way from the edge part of the element, or from a newly drawn cup. By blow-moulding against warm mould walls, the cup, the material of which is at a temperature above the glass transition temperature Tg, is reshaped in such a way that it has exactly the form of the intended end product. In certain applications, a warm blowing mandrel is used in order to prevent excessive cooling of the material during the blow-moulding step.
It can be seen from what has been said that the combination of drawing, until flow sets in to obtain an element, redrawing of the cup of the element formed and a blow-moulding step offers many optional possibilities for the shaping of different types of articles.
An article produced in the manner described above is thus not only suitable for use as a container, but many applications are possible.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be described in detail with reference to the drawings, wherein
FIGS. 1-2 show optional embodiments of bands suitable for reshaping,
FIG. 3 shows an element having a bottom part of the body, consisting mainly of amorphous material,
FIGS. 4-10 show the principles of devices for drawing of the element,
FIG. 11 shows a part of a device for redrawing of the cup of the element,
FIG. 12 shows the cup of the element before redrawing,
FIG. 13 shows the cup of the element after partial redrawing,
FIG. 14 shows the cup of the element after complete redrawing,
FIG. 15 shows the cup of the element, having the part of the cup, which was partially redrawn, according to FIG. 13, after renewed redrawing,
FIG. 16 shows a container produced from a cup according to FIG. 15,
FIGS. 17-19 show the counterparts to FIGS. 12-14, the bottom part of the cup having sections of amorphous material and
FIGS. 20-22 show optional embodiments of blow-moulded articles.
DETAILED DESCRIPTION
FIGS. 1-2 show a band or a blank 14', 14" of thermoplastic, the bands or blanks being seen from above. In the figures, annular material zones 16', 16" or 17', 17" are represented. Moreover, a material zone 15', 15" is indicated which is surrounded by the original annular material zone 17', 17". The material zone 16 marks that zone which, on drawing of the blank, is clamped in between the clamping devices 30a-b (see FIG. 4). The material zone 15 marks that zone which, on drawing of the blank, is in contact with the press face of the press device 20 (see FIG. 4). The material zone 17 marks that zone which, on drawing of the blank, is brought into the state of flow.
An element 10 consisting of an edge part 12 of the body 13 is seen in FIG. 3. The body in turn consists of a wall part 18 and a bottom part 11. In the figure, the wall part consists of drawn material of reduced thickness compared with the thickness of the starting material. The bottom part 11 consists of material which, while retaining its material properties, has been displaced in the axial direction of the body. Moreover, a zone 19 is marked in which material belonging to the edge part 12 had been transformed into the state of flow.
In FIGS. 4-8, a number of clamping devices 30a, 30b which fix the blank 14 can be seen. A press device 20 having a press face 21 is located between the clamping devices 30. In FIG. 4, the press device is in a position in which the press face 21 is located directly next to the upper surface of the blank 14. In FIG. 5, the press device was shifted downwards, flow of the material having started from a transition zone at which the original thickness of the blank is reduced to the drawn thickness of the element. It is seen that the drawing takes place between the outer surface of the press element and the inner surface of the clamping devices without contact of the drawn material with these surfaces whereby a so-called free drawing takes place. In FIG. 6, the press device has been shifted to such an extent that an element according to FIG. 3 has been formed. In FIG. 7, the press device was yet further shifted, further flow of the material having taken place. An element 10' has thus been formed, the body 13' of which has a bottom part 11, the central sections of which consist of amorphous undrawn material which is surrounded by drawn oriented material in which flow has taken place. Finally, in FIG. 8, the press device 20 has been shifted to such an extent that virtually the entire material in the bottom part 11" of the body 13" has undergone flow. An element 10' has thus been formed in which both the wall part and the bottom part of the body have a reduced wall thickness because the material has been in the state of flow and has at the same time been oriented.
In FIGS. 9-10, an optional embodiment of the clamping devices 33a-b is represented, which are provided with cooling channels 31 and heating channels 34. In the figures, only the feedline for the heating channels is shown, whilst the discharge line for the heating channels is located behind the feedline in the figures and is indicated by the upward-pointing arrow. The cooling channels, like the heating channels, are covered by plate-like covers 35, the other surface of which at the same time represents the contact surface of the clamping devices for clamping the blank. An insulation 32 separates the cooled zone of the clamping devices from the heated zone. In certain applications, the heating channels are used as the cooling channels in the same way.
Furthermore, the figures show an optional embodiment of a press device 20a which also has cooling channels 22. The cooling channels are covered by a cooling jacket 23 which at the same time represents the outer contact surface of the press device opposite the material during the process of drawing the latter. FIG. 9 shows a position of the press device, which corresponds to the position shown in FIG. 5, and FIG. 10 shows a position of the press device, which corresponds to the position in FIG. 8. The press device is constructed with a face of rotationally symmetrical curvature, which is shaped in such a way that, on drawing within the flow range, the material is always in contact with the cooling jacket, whilst that material which has not yet been in the state of flow is not in contact at any point with any device in the zone between the press device and the clamping devices.
Heating of the material with the aid of the heating channels 34 has the purpose of increasing the readiness of the material to flow. Heating is limited, however, in such a way that the temperature of the material is always lower than the glass transition temperature Tg. Heating makes it possible to allow the drawing step of the material to continue a little into the zone between the jaws of the clamping devices, as shown in FIG. 10. Another optional application, where the increased readiness of the material to flow is exploited, is obtained when, during the drawing step, the zone of initial flow of the material is directed to the zone next to the inner edges of the clamping devices. After flow has taken place, the flow zone is gradually displaced in the direction away from the clamping devices towards the bottom of the press device, as the press device gradually shifts downwards as in the figures.
The result of this is that flow always propagates in the same direction, and a new start of flow is avoided, such as takes place when the embodiment of the invention shown in FIGS. 4-8 is used.
FIG. 11 shows a device for redrawing the element formed before. In the figure which shows only a part of the device, a press plunger 40, a counterholder ring 41, a clamping ring 42 and a wall part 18 in the element are seen, the wall part being in the process of shaping. Moreover, the bottom 11" in the body 13 of the element is seen. The clamping ring 42 is provided with a calibration device 43 which determines the thickness of the material, drawn anew, in the wall part 18.
FIG. 12 shows an element body 50 which has been formed by means of the press device 20a according to FIG. 9 and in which the edge part of the element has been produced from the body. In FIG. 13, the shaping process of the body 50 was initiated with the aid of a device shown in FIG. 11. The shaping process has progressed to such an extent that a mainly cylindrical larger part, having the same diameter as the body 50, and a shorter part 59 have been formed. In FIG. 14, the shaping process has been completed, a mainly cylindrical body 52 of the same diameter as in the shorter part in FIG. 13 having been formed.
FIG. 15 shows a body 53, the shorter part 59 of which has been reshaped with the aid of a device shown in FIG. 11 for the purpose of further reducing the diameter of the shorter part 59'. There is a transition 58 between the shorter cylindrical part 59' and the larger part of the body 53.
FIG. 16 shows a bottle-like container 70' produced from a body 53 according to FIG. 15. The bottom part of the shorter part 59' has been severed and replaced by a closure 55, for example a cap. The mouth edges formed on severing the bottom part were expanded and beaded, after which the material in the beaded material zones has preferably been given an increased crystallinity as a result of heating the material up to the crystallization temperature. This gives additional strength at the mouth edge so that the latter is well suited for closing the container, for example by means of a cap or a crown cork. The transition, already mentioned, between the shorter part and the larger part of the body now forms a bottle neck 58'. The figure also shows how an end disc 56 is fixed at the other end of the container 70', after the container has been filled. As a result of expanding, beading and heating of the material, material sections are here also obtained which are suitable, for example, for fitting an end disc by crimping, in order to close the container.
FIGS. 17-19 show counterparts to FIGS. 12-14. The figures show how an element body, formed from the body 11' according to FIG. 7, is subjected to an axial lengthening, with simultaneous reduction in the diameter of the body, and forms an almost completely cylindrical body 61, the bottom part of this body consisting of a material section 62 of mainly amorphous material. During the shaping process, an intermediate form of the body results, which is marked 60 in FIG. 18.
In the embodiment of the invention in which a body is formed which comprises an amorphous bottom section, a material zone is also obtained which is suitable as a fixing material for welding on additional parts to the body. By rendering the material crystalline, a zone of extreme dimensional stability is obtained, whereby it becomes possible to use the container for storing liquids under pressure, for example beverages to which carbonic acid has been added, without a risk of deforming the bottom part. The concept of the invention also comprises the replacement of the plane embodiment of the bottom part by a convex or concave face, depending on the particular wishes which apply corresponding to the individual applications.
FIGS. 20-22 show optional embodiments of blow-moulded containers. All the containers are closed by end discs in the manner already described in connection with FIG. 16. Of course, this combination of a blow-moulded container and an end disc is to be regarded only as an example of the possibilities available for closure.
FIG. 20 shows an embodiment in which all the material in the blow-moulded container consists of material previously drawn. The container is formed from a body part either according to FIG. 12 or according to FIG. 14.
FIG. 21 shows an embodiment of a blow-moulded container which has been formed from a body part according to FIG. 17 or FIG. 19. On blow-moulding, the amorphous material zone 22 remained in the amorphous state without change, and it represents a thicker section in the bottom part of the container. In certain embodiments, this section is heated up to the crystallisation temperature of the material in order to form a bottom section which is particularly suitable for withstanding deformation forces, for example, forces due to an internal pressure in the container. The amorphous material is also suitable for the purpose of welding additional plastic parts thereto.
FIG. 22 shows an embodiment of a blow-moulded container which has been formed from a body part, the bottom of the body part consisting alternately of material sections, which have been drawn until flow sets in, and of those material sections which have retained their original thickness. In this way, a simple amorphous material section 21 has been formed which is surrounded by an annular amorphous section 72 which is located below the central section. The central section and the annular section are connected by material which has been drawn until flow sets in. The annular material section thus forms standing surfaces for the container. The parts forming the shell of the container are as a rule shaped from redrawn material. At least in the cases where the container has a relatively large axial dimension, such redrawing is necessary.
Blow-moulding is carried out in any known manner at a temperature of the material, which is above the glass transition temperature Tg. Normally, blow-moulding takes place against heated mould walls. In certain illustrative embodiments, a heated elongate blow mandrel is required in order to avoid excessive cooling of the material during the blow-moulding step.
The material oriented by flow possesses improved strength properties in the direction of orienting, which is largely the same as the direction of drawing the material. Since the material has been heated to a temperature above the glass transition temperature Tg, there are no difficulties in a blow-moulding process with regard to reshaping the element by stretching the material in a direction which is mainly at right angles to the said direction of orienting. An element reshaped in this way forms, for example, a container having a central shell surface of a diameter which exceeds the diameter of the opening, and having a bottom which consists of a standing surface which represents the transition between the lower edge of the shell surface and the bottom surface, the bottom surface either being slightly concave or consisting of annular material sections which are displaced relative to one another in the axial direction of the container.
The above description merely represents examples for the application of the invention. The invention allows of course that a number of combinations of drawing steps take place, zones of drawn and undrawn material also forming alternately. For example, the body consists of wall parts with sections which contain undrawn material, whilst the bottom part consists of sections, for example annular sections, which contain undrawn material and which are displaced in the axial direction of the body relative to the lower edge of the wall part.
The concept of the invention comprises many optional embodiments. According to one of these, drawing until the material in the body of the element flows is effected by a number of successive drawing steps, the contact area of the press device decreasing for each drawing step. The result of this is that the width of the material zone 15 is adapted to the extent to which the drawing step has proceeded.
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A process for the manufacture of articles from a thermoplastic of polyester or polyamide type, preferably of polyethylene terephthalate, the element consisting of an edge part which surrounds a body in an arrangement in which the latter is sunk relative to the edge part. The element is formed from a blank of mainly amorphous material or from a material having a crystallinity of less than 10%. The blank consists, for example, of a flat plate, a blank shell or the like. The body or parts thereof are shaped by stretching the blank until that material flows which is located within the material sections of the blank, which form the edge part in the element, the material stretched up to flowing in the body assuming a crystallinity of between 10% and 25%, while the crystallinity in the material in the edge part and in the unstretched parts retains its original value of less than 10%. At least the body of the element is expanded against warm mould walls until the final shape of the particular article is obtained. Optionally, the expansion is preceded by a number of drawing steps with an axial elongation of the body coupled with a simultaneous reduction in its dimensions at right angles thereto.
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This is a continuation of Application Ser. No. 349,812 filed Feb. 18, 1982, now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for deicing objects, and to a method for transmitting overpressure through a passage which is blocked for dynamic pressure.
Rapid tempering has a number of applications. Thus, it is desirable to be able to quickly deice and dry vehicles, such as railway wagons, cars and deck containers. In winter it is also desirable to be able to quickly deice material, such as iron girders, which are stored outdoors, before they are used for instance in a welding shop, like a shipyard or the like. Another field of application is thawing of frozen products.
The object of the present invention is to provide a method and provide an apparatus for deicing objects, which method and apparatus are energy saving and, especially at deicing, do not result in large contents of moisture of the ambient air with associated problems of condensation on cold surfaces.
This object is obtained by a method of deicing objects which is characterized in that air or another gaseous medium having a low overtemperature is blown with high speed onto the object to be tempered, and by an apparatus for deicing objects which is characterized in that means are provided to heat air or another gaseous deicing medium, and in that exhaust means are provided to exhaust said heated medium with high speed in jets directed towards objects to be tempered.
Another object of the invention is to suggest a method of developing a counterpressure to prevent undesired flow of air or diffusion of gas to a room in which a dynamic counterpressure cannot be produced. In this way also the abovementioned problem of condensation can be further reduced by producing such a counterpressure by dry air around those surfaces which are exposed to condensation.
This object is obtained by a method of transmitting an overpressure through a passage which is blocked for dynamic pressure, which method is characterized in that a static pressure is produced across the orifice of said passage.
Deicing of railway wagons has so far been effected only by heat transfer to the underframe or bogie wagon or the train and this has been done by air of high temperature and moderate speed. By means of air heaters equipped with fans, air having a temperature exceeding 50° C., typically 70° C., has been oriented towards parts of the bogies and other places where the quantity of ice usually is most important with a typical striking velocity of 0.5 m/sec.
An obvious disadvantage of this previously known solution is that the high temperature which is used results in evaporation of large quantities of water by the hot air which gives the air high contents of moisture. Evaporation of water consumes large quantities of heat and installed heating effect must be dimensioned for ice melting as well as evaporation of a large quantity of water. The energy consumption therefore becomes unnecessarily large. The moisture absorbed by the air also results in a need for fast circulation of air in the room in which the deicing is performed for the drying of the air.
In the method and apparatus according to the invention the transfer of heat from the air to the bogie wagon of the train is performed by convection.
The rate of transfer which is a function of the coefficient of heat transfer for transmission of heat by convection, α, and the temperature difference between the bogie wagon or wagon chassis and intake air, Δt, is given by
Q=α·Δt
where Q denotes the transferred quantity of heat.
A lower temperature of the intake air thus can be compensated for by a higher value of α.
The coefficient of heat transfer α is a function of the radiation temperature, the ambient temperature and the speed of the air towards the surface in question.
The radiation part of the heat transfer is equal to 0.96· emission number·Δt s , where
0.96=Stefan Boltzmann's number,
emission number for water, ice, frost=0.95-0.98, for painted surface=0.90-0.97,
Δt s =counterradiation temperature.
The radiation exchange in deicing of bogie wagons or wagon chassis takes place between the floor of the hall and the bogie wagon or wagon chassis and is influenced only in a marginal manner by flows of air and rates of flows.
The influence on the heat transfer by ambient temperature is according to G Brown for a cold surface:
2.08·Δt.sup.0.31 ·L.sup.-0.08 k
where
Δt=the temperature difference between air and surface in °C., and
L=characteristic length in meters.
The above temperature difference Δt can to a great extent be influenced in the present invention since the temperature of the intake air can be chosen.
The relation above between the heat transfer and the temperature difference Δt is graphically represented in FIG. 1.
The air speed towards the bogie wagon or wagon chassie has an influence on the heat transfer for air speeds exceeding 5 m/sec. This influence can be roughly estimated from the formula
α.sub.v =7.6·v.sup.0.78
where v=air speed in m/sec and is graphically illustrated in FIG. 2.
Like the temperature difference Δt also the air speed v can be influenced in the apparatus according to the invention in which controlled blowing is used.
From the above relationship and the graphical illustration in FIGS. 1 and 2 it appears that a change in the speed of the air of 0.5 m/sec gives roughly the same change of the α-value as a change of the temperature of 40° C. The heat transfer is a function of the α-value and the temperature difference, as seen above, and therefore an increase of the speed is compensated for by a temperature difference which is smaller than the one which the change in the α-value alone indicates. A reduction of the temperature difference with 20° C. can, in principle, be compensated for by an increase of speed of about 1 m/sec.
Thus, in the present invention the heat transfer from the intake air to ice/wagon is performed as quickly as or quicker than in the abovementioned prior art with a considerably lower air temperature since the higher speed results in a larger heat transfer number.
A fundamental condition for the use of a high air speed is that this speed shall be present on all the surfaces to be treated. In the apparatus according to the invention this is realized by jet streams of air or another gaseous tempering medium directed towards the object to be treated.
The advantages of using an increased air speed instead of high overtemperature are among others that the zone nearest to the wagons does not get a disagreeably high temperature. As indicated above a high temperature also results in evaporation of large quantities of water which requires considerable energy and consequently gives a high energy consumption. Through the evaporation the air gets large contents of moisture which in its turn gives rise to condensation on cold surfaces. If the air is supposed to hold a relative humidity of 30% the water contents are changed from 30 g/kg to 10 g/kg when the air temperature is decreased from about 55° C. to about 35° C. Translated to a cold surface subjected to condensation deposit this means that a surface temperature of about 15° C. has deposit of damp for the cooler air whereas deposit of damp occurs up to a temperature of about 32° C. for the warmer air.
According to an advantageous further developement of the invention circulating air is used for the deicing whereby large evaporation is avoided even if the moisture contents of the air are high.
According to another advantageous embodiment of the invention a large fraction of exterior air is used in a drying step following the thawing step whereas only a smaller part or the air is circulated. The exterior air is then preheated.
To prevent condensation in the driving motors of the trains during deicing dry air is forced to pass through the cooling air inlets of the motors. In the prior art this has been done by means of hoods which are connected to flexible tubes and placed over the cooling air inlets, with the dried air of indoor temperature being supplied through said flexible tubes during the deicing.
According to the present invention humid deicing or defrosting air is prevented from penetrating "through the backway" into the air outlets of the motors and condensing on windings and other surfaces of the motors by producing a static overpressure around the air inlets on the sides of the wagon since dynamic pressure cannot be transmitted because of the so-called labyrinth grating structure of the air inlets. The static overpressure is produced by blowing air at high rates towards the cooling air inlets of the motors, with a static overpressure being produced around the air inlet. The moisture content of the air must be lower than the dew point of the motors, and is therefore preferably formed by dry, preheated exterior air. By the thus developed static pressure the dry air is pressed through the motors and prevents humid air from penetrating through the cooling air outlets and condensing on cold surfaces in the motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 respectively graphically illustrate a variation in a coefficient of heat transfer with a temperature difference and a rate of flow;
FIG. 3 is a top view of a deicing plant for railroad trucks or wagons constructed in accordance with the present invention;
FIG. 4 is a transverse cross-sectional view of a portion of the deicing plant in FIG. 3;
FIG. 5 is a transverse cross-sectional view of another embodiment of the deicing plant constructed in accordance with the present invention provided with means for producing a static overpressure at cooling air inlet of motors; and
FIG. 6 is a detail view of a cooling air inlet provided with a means for producing a static overpressure.
DETAILED DESCRIPTION
The embodiment shown in FIGS. 3 and 4 of the apparatus according to the invention for deicing railway trucks or wagons comprises two hot air passages 2, 4 separated by a draining room 6. Outside the hot air passages 2 and 4 return passages 8 and 10 extend parallel to the hot air passages. On the hot air passages 2, 4 rails 12, 14 are supported by supports 16, 18 for carrying trucks or wagons 20 to be deiced.
The air in the passages 2 and 4 is exhausted through nozzles 22 which are supported by steel pipes 24 connected to the passages 2, 4. The nozzles are disposed more closely to each other in the bogie and motor regions of the trucks or wagons, of FIG. 3, and directed to give as effective thawing as possible.
The major part of the air exhausted for thawing through the nozzles 22 is sucked back into the return passages 8, 10 through apertures 26 provided with valves so that a substantially circulating flow of air is used for the thawing. This is important as the thawing air has comparatively large contents of moisture which otherwise should require a much more effective ventilation of the hall in which the treatment takes place. As shown in FIG. 3, the passages 2, 4, 8, 10 are connected by fan sets 28' situated in hollows, with the fan sets supplying two sections of the passages.
In practice, a deicing plant having the apparatus according to the invention is formed with two or possibly more tracks for deicing railway trucks or wagons, with the tracks extending parallel to each other, as shown most clearly in FIGS. 3 and 4. The return passage 8 extending between said tracks then serves as return conduit for thawing air from both treatment tracks.
With the adjustment valves 26 the recirculating part of the air can be controlled. During thawing a fraction is drawn off corresponding to the quantity of air which is drawn off for ventilation of the hall, whereas the rest, typically 80 through 90%, is recirculated. After the thawing motors and bogie, are dried, a large fraction of dry exterior air then being used.
The fan sets 28 are in addition to fans for increasing the pressure means for preheating exterior air to be used. For this preheating a fluid coupled heat recovery system of the type disclosed in, for example, U.S. Pat. No. 4,061,186, so-called ECOTERM-system, can preferably be used. The total amount of recirculating air is heated with separate heating means.
A railway truck or wagon can typically contain 1000 kg of ice and snow when brought into the hall for deicing and drying. With a plant according to the invention deicing and drying can be performed in about three to four hours. 5 m 3 /sec of blowing air having a temperature of about 30° C. is then used. During the thawing about 0.5 m 3 /sec is drawn off, corresponding to necessary ventilation of the hall, whereas the rest is returned. The temperature of the recirculating air is during the deicing period typically 15° C. below that of the blown hot air. The striking velocity of the blown air towards parts of the bogie wagons or chassis to be deiced is normally in the range 5 to 35 m/sec depending on the distance between nozzle and vehicle part as well as the design of the nozzle. It is then of basic importance that there is a high velocity on all surfaces to be deiced. Also velocities still higher than those mentioned can be used if necessary.
In FIG. 5 an alternative embodiment is shown of the apparatus according to the invention. In this embodiment hot air is supplied through circular sheet metal drums 28, 30 which extend along the supports 16, 18 which are supporting the rails 12, 14. On the drums 28, 30 nozzles 22 are disposed to blow the air in the form of jets towards the surfaces to be deiced. The outer nozzles 22 are preferably provided only near boggies and converters of the wagon or truck 20. In the same way as in the embodiment shown in FIGS. 3 and 4 return passages 32, 34 are disposed outside the rails 12, 14 for recirculation of the thawing air, said passages having apertures 36 provided with valves.
Between the rails 12, 14 a draining 38, 40 is provided in the floor in the same way as in the previously described embodiment for draining off melted ice and snow.
In both the described embodiments the nozzles are mounted on conduits of a material having a high corrosion resistance, such as stainless steel, while the nozzles themselves are formed in a flexible material, such as rubber, in order not to be damaged by falling blocks of ice.
To prevent humid thawing air from penetrating "the backway" into the air outlets 44 of the motors 42 and condensing on windings and other surfaces in the motors, dry air is, according to the invention, forced to pass through the cooling air apertures of the motors 42. The cooling air inlets 43 of the motors 42 are covered with a so-called labyrinth grating through which a dynamic pressure cannot be transmitted. According to the invention a static overpressure is instead produced around the air inlet 43 by means of air jets exhausted through nozzles 46. The air which then is exhausted through the nozzles 46 shall have contents of moisture which are lower that the dew point of the motors 42, and said air can preferably consist of dry, heated exterior air. By the static overpressure produced at the air inlet the dry air will be forced through the outlet grating on the side of the wagon or truck and down through the passage 48 and through the motors, see FIGS. 4 and 5, so that humid air cannot penetrate into the motors and condense on cold surfaces therein.
Two nozzles 46 are preferably provided to blow air obliquely from the top downwards towards the inlet 43, as illustrated in FIG. 6. The rate of blowing of the air is preferably substantially the same as the speed of the air from the nozzles 22 and the striking velocity is normally in the range 5 to 40 m/sec. Through the generally favorable positioning of the nozzles the striking velocity is in general in the upper part of the interval. Also striking velocities above this interval can be used if required.
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The present invention discloses an apparatus for deicing the exterior of a railway vehicle that uses heated air which is blown at a railway vehicle at 5-35 m/sec and subsequently recycled for reblowing.
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BACKGROUND OF THE INVENTION
This invention relates to compounds having activity as an antifungal agent and as an immunosuppressant.
In particular, this invention relates to analogs of the compound rapamycin, which is a compound of the following formula: ##STR2## which is useful as an antifungal agent and is useful in the suppression of the immune response.
As early as 1975, rapamycin was identified as an antifungal antibiotic harvested from a Streptomyces hygroscopicus culture, which culture was isolated from an Easter Island soil sample. See Vezina et al., J. Antibiot. 28, 721-726 (1975); and U.S. Pat. No. 3,929,992, which issued to Sehgal, et. al. Dec. 30, 1975. The ability of this compound to inhibit the immune response was first described by Martel, R. et al., Can. J. Physiol. Pharmacol., 55, 48-51 (1977). In this work, the authors show the utility of this compound in inhibiting the response to allergic encephalomyelitis, adjuvant-induced arthritis and antibody production in rats. More recently, Calne, R. Y. et al., has shown rapamycin to be immunosuppressive in rats given heterotopic heart allografts. Calne, R. Y. et al., Lancet vol. 2, p. 227 (1989). Equally important, less toxicity was experienced than would be anticipated with FK-506 (U.S. Pat. No. 4,894,366, assigned to Fujisawa, which issued on Jan. 16, 1990), with which rapamycin shares some structural features.
More recently, rapamycin has been shown to be useful in combination therapy with Cyclosporin A. This combination has the advantage of reducing the amount of Cyclosporin A required to produce its immunosupressive effect, such as in heart, kidney, bowel, pancreas or other transplantation, and thereby effectively reducing the nephrotoxicity inherent in treatment with Cyclosporin A. See Stepkowski, S. M. et al., Transplantation Proceedings, vol. 23, pp 507-508 (1991).
As appreciated by those of skill in the art, and as exemplified by Harding, M. W. et al., Nature, vol. 341, p. 758-760 (1989) and Devlin, J. P. and Hargrave, K. D. Tetrahedron, vol. 45, p. 4327-4369 (1989), Cyclosporin A, FK-506, rapamycin, and analogs thereof, can be expected to share a broad range of utilities as immunosuppressive agents. Cyclosporin A, FK-506, rapamycin and analogs thereof find utility in the prevention of rejection or organ and bone marrow transplants; and in the treatment of psoriasis, and a number of autoimmune disorders such as type 1 diabetes mellitus, multiple sclerosis, autoimmune uveitis, and rheumatoid arthritis. Additional indications are discussed infra.
SUMMARY OF THE INVENTION
This invention relates to a compound assigned of Formula I: ##STR3## which compound is an analog of rapamycin and which compound is an antifungal agent and a useful immunosuppressant.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to a compound of assigned Formula I, ##STR4##
The compound of Formula I may also be described as 7,29-bisdesmethyl rapamycin. The invention also relates to substantially pure compound of Formula I. For purposes of this specification substantially pure shall designate a purity in excess of 98% and free of rapamycin.
This invention also relates to pharmaceutical compositions for inducing immunosuppresion in a subject in need of such treatment, comprising: administration of a therapeutically effective amount of 7,29-bisdesmethyl rapamycin.
In view of its immunosuppressive activity, 7,29-desmethyl rapamycin is useful for the prophylaxis and treatment of diseases and conditions requiring a reduction of the immune response. Thus they may be used to suppress the proliferation of lymphocytes and immunocytes, e.g. in treatment of autoimmune diseases or in preventing the rejection of transplants e.g. skin, lung, heart, heart-lung, bone-marrow, kidney, spleen and corneal transplants.
Specific auto-immune diseases for which the compound of formula I are useful include all of those for which treatment with cyclosporin and/or FK-506 has been proposed or used, for example, aplastic anaemia, pure red cell anaemia, isopathic thrombocytopaenia, systemic lupus erythematosus, polychondritis, scleroderma, Wegener granulomatosis, chronic active hepatitis, myasthenia gravis, psoriasis, Steven-Johnston syndrome, idiopathic sprue, Crohn's disease, Graves opthalmopathy, sarcoidosis, multiple sclerosis, primary biliary cirrhosis, primary juvenile diabetes, uveitis posterior, interstitial lung fibrosis and psoriatic arthritis as well as insulin-dependent diabetes mellitus, nephrotic syndrome and AIDS.
This invention also relates to a pharmaceutical compositions for inducing immunosuppression in a subject in need of such treatment, comprising a therapeutically effective amount of Cyclosporin A and 7,29-bisdesmethyl rapamycin.
This invention also relates to a method of inducing immunosuppresion in a subject in need of such treatment, comprising administration of a therapeutically effective amount of 7,29-bisdesmethyl rapamycin.
The compound of Formula I can be conveniently prepared by fermentation of a culture of Streptomyces hygroscopicus such as NRRL 5491, which strain can be obtained from the culture collection at the National Center for Agricultural Utilization Research, USDA, ARS, Peoria I11. NRRL 5491 is also available from the American Type Culture Collection, Rockville, Md. as ATCC 29253. This organism, and procedures for standard cultivation are described in Vezina et al., J. Antibiot. 28, 721-726 (1975); Sehgal et al J. Antibiot. 28, 727-732, and U.S. Pat. No. 3,929,992; said references being hereby incorporated by reference.
As appreciated by those of skill in the art, microorganisms for production of 7,29-bisdesmethyl rapamycin may include other natural or artificial mutants or variants derived from the described culture. The artificial production of mutant strains may be achieved by physical or chemical mutagens, for example, ultraviolet irradiation or N-nitrosoguanidine treatment and the like. Recombinant DNA techniques such as protoplast fusion, plasmid incorporation, gene transfer and the like are also envisioned.
In general production of 7,29-bisdesmethyl rapamycin can be achieved by cultivation of NRRL 5491 in the presence of sinefugin by conventional aerobic fermentation of suitable nutrient media which contain sources of assimilable carbon, nitrogen and inorganic salts. Sinefungin concentration may range from 0.1 to 5.0 mM; preferably 1.0 mM.
In general, many carbohydrates such as glucose, maltose, mannose, sucrose, starch, glycerin, millet jelly, molasses, soy bean and the like can be used as sources of assimilable carbon. Sources of assimilable nitrogen includes such materials as yeast and casein hydrolysates, primary yeast, yeast extracts, cottonseed flour, soybean solids, wheat germ, meat extracts, peptone, corn steep liquor, and ammonium salts. The inorganic salt nutrients which can be incorporated in the culture medium are the customary salts yielding sodium, iron, magnesium, potassium, cobalt, phosphate and the like. In general, of course, the techniques employed will be chosen having regard to industrial efficiency. The nutrient media described herein are merely illustrative of the wide variety of media that may be employed and are not intended to be limiting.
The fermentation has been carried out at temperatures ranging from about 20° to 32° C.; however, for optimum results it is preferable to conduct the fermentation at about 27° C. The pH of the medium is controlled at about pH 6-7 by the use of suitable organic or inorganic buffers incorporated into the fermentation medium or by the periodic addition of a base such as sodium hydroxide. Good yields of 7,29-bisdesmethyl rapamycin can be achieved within 30 to 96 hours. Variation of the medium or the microorganism will alter the yield of the compound of 7,29-bisdesmethyl rapamycin and/or its rate of production. The preferred media compositions are set forth in the examples. The terms "seed" and "production media" are employed as terms of the art. Generally, a seed medium supports rapid growth of the microorganism and a small portion thereof (seed) is used to inoculate a production medium for large scale fermentation.
Specific examples of fermentation isolation and recovery conditions we have found to be advantageous are provided in the Examples Section below.
As stated above, in view of its immuno-suppressive activity, 7,29-bisdesmethyl rapamycin is useful for the prophylaxis and treatment of diseases and conditions requiring a reduction of the immune response. Thus they may be used to suppress the proliferation of lymphocytes and immunocytes, e.g. in treatment of autoimmune diseases or in preventing the rejection of transplants e.g. skin, lung, heart, heart-lung, bone-marrow, kidney, spleen and corneal transplants.
Specific auto-immune diseases for which the compound of formula I are useful include all of those for which treatment with cyclosporin and FK 506 has been proposed or used, for example, aplastic anaemia, pure red cell anaemia, isopathic thrombocytopaenia, systemic lupus erythematosus, polychondritis, scleroderma, Wegener granulomatosis, chronic active hepatitis, myasthenia gravis, psoriasis, Steven-Johnston syndrome, idiopathic sprue, Crohn's disease, Graves opthalmopathy, sarcoidosis, multiple sclerosis, primary biliary cirrhosis, primary juvenile diabetes, uveitis posterior, interstitial lung fibrosis and psoriatic arthritis as well as insulin-dependent diabetes mellitus, nephrotic syndrome and AIDS.
For all these uses the dosage will, of course, vary depending on the compound employed, mode of administration and treatment desired. However, in general, satisfactory results are obtained when administered at a daily dosage of from about 1 mg to about 200 mg per kg animal body weight, conveniently given in divided doses 2 to 4 times a day or in sustained release form. For the larger mammals, the total daily dosage is in the range from about 50 to about 5000 mg, and dosage forms suitable for oral mg (e.g. 25-300 mg) of the compounds admixed with a solid or liquid pharmaceutical carrier or diluent.
The present invention also provides a pharmaceutical composition comprising a compound of formula I such as in association with a pharmaceutical carrier or diluent.
Such compositions may be in the form of, for example, a solution, a tablet or a capsule and in ointments especially for the treatment of psoriasis.
7,29-bisdesmethyl rapamycin may be administered by any conventional route, in particular in accordance with means currently practiced in relation to administration of cyclosporin, in particular via intravenous infusion, e.g. in the case of organ transplant, pre- and immediately post-transplant, as well as during episodes of gastrointestinal disturbance which might otherwise impair absorption, or orally, e.g. in the form of an oral solution.
Biological activity as a immunosuppressant can be measured in terms of inhibition of interleukin-2 production, and inhibition of T-cell proliferation (The utility of the invention can also be shown by its ability to inhibit various fungus). Results are provided in the Examples section.
T-cell proliferation was measured in mouse T-cell cultures stimulated with ionomycin plus phorbol myristate acetate (PMA). (This assay is described in detail in Dumont, F. J. et al, J. Immunol. (1990) 144:251.) Spleen cell suspensions from C57B1/6 mice were prepared and separated on nylon wool columns. The recovered T-cells were suspended at 10 6 cells/ml in complete culture medium with addition of ionomycin (250 ng/ml) and PMA (10 ng/ml). The cell suspension was immediately distributed in 96 well-flat bottom microculture plates at 200 μl/well. Control medium or various concentrations of test compound were added in triplicate wells at 20 μl/well. Parallel cultures were set up with exogenous IL-2 (50 units/ml). The plates were incubated at 37° C. in a humidified atmosphere of 5% CO 2 -95% air for 44 hours. The cultures were then pulsed with tritiated-thymidine (2 uCi/well) for an additional 4 hour period and cells were collected on fiber glass filters using a multisample harvester. Incorporated radioactivity was measured in a BETAPLATE COUNTER (Pharmacia/LKB, Piscataway, NJ) and the mean count per minute (cpm) values of triplicate samples calculated. The percent inhibition of proliferation was calculated according to the formula: ##EQU1##
The following examples illustrate the preparation of this compound and, as such, are not to be construed as limiting the invention set forth in the claims appended hereto.
EXAMPLE 1
Production of 7,29-Bisdesmethyl Rapamysin
The producing culture for production of rapamycin was NRRL 5941, which is also known as ATCC #29253. Seed cultures were started from either a well sporulated slant of the culture grown on Bennetts agar medium consisting of 0.1% yeast extract, 0.1% beef extract, 0.2% N-Z AMINE A and 1.0% glucose, or 100 ul of 3×10 9 spores preserved in 10% glycerol and stored at -79° C. Seed medium A consisted of:
______________________________________Component g/L______________________________________KNO.sub.3 2.0Glucose 20.0Yeast Extract 20.0HYCASE SF.sup.1 20.0FeSO.sub.4.7H.sub.2 O 0.025NaCl (12.5%) 4.0 mlMgSO.sub.4.7H.sub.2 O (12.5%) 4.0 mlMnSO.sub.4.H.sub.2 O (0.5%) 1.0 mlZnSO.sub.4.7H.sub.2 O (1.0%) 1.0 mlCaCl.sub.2.2H.sub.2 O (2.0%) 1.0 mlPH was adjusted to 7.0 before sterilization.______________________________________ .sup.1 HYCASE SF is a product of SHEFFIELD PRODUCTS, Norwich, N.Y.
Seed incubations were conducted with 44 ml of medium in a 250 ml baffled erylenmeyer flask and, after inoculation as stated above, incubated at 27° C. and 220 RPM for 48 to 72 hours.
Production flasks were inoculated with 1.0 to 1.5 ml of seed culture, tube fermentations inoculated with 0.1 ml, into production medium RAP-21 consisting of:
______________________________________Component g/L______________________________________Glucose 20.0Glycerol 20 0(NH.sub.4).sub.2 SO.sub.4 5.0KH.sub.2 PO.sub.4 2.5K.sub.2 HPO.sub.4 2.5L-Lysine 4.0NUTRISOY.sup.1 30.0Morpholinoethanesulfonic acid 21.3(MES)PH was adjusted to 6.3 beforesterilization.______________________________________ .sup.1 NUTRISOY is a product of ARCHER DANIELS, Midland, Michigan.
Production incubations were carried out with 30 to 44 ml of medium in a 250 ml non-baffled erylenmeyer flask or 3.0 ml in a 25×150 mm tube shaking at 220 RPM at 25° C. At 43 to 48 hours a sterile solution of sinefungin was added to the flask so that the final concentration of sinefungin was between 0.1 and 1.0 mM, and the fermentation continued for an additional 24 to 48 hours.
The fermentation was harvested and the fermentation broth extracted with an equal volume of MeOH. After shaking for 30 minutes, the extract was centrifuged and the supernatant analyzed by high performance liquid chromatography (HPLC).
HPLC analysis consisted of:
Solvent composition 1: WATERS 510 pumps (WATERS ASSOCIATES, Milford, Mass.) delivering a mobile phase composed of MeOH/Water (76:24) at 1.0 ml/min.
Composition 2: Gradient conditions with an initial composition of acetonitrile/H 2 O (60:40) maintained for 5.0 minutes, and then changing to acetonitrile/H 2 O (75:25) in a linear fashion over a 20 minute time interval. The final composition was maintained for 10 minutes before the column was re-equilibrated at the initial conditions.
Composition DESRAP: a gradient solvent run with initial conditions of MeOH/0.1% H 3 PO 4 (68:32) changing to a ratio of (83:17) in a linear fashion over 30 minutes before re-equilibration to initial conditions.
Column: WHATMAN PARTISIL 5 ODS-3 4.0×250 mm, operated at room temperature.
Detector: WATERS Model 490 variable wavelength detector and a WATERS Model 990 Photodiode array detector. Optimal wavelength for detection was 277 nm.
Injection of 20 ul of methanol extract of the sinefungin treated fermentation produced a chromatogram obtained using the DESRAP solvent conditions with 7.29 bisdesmethyl rapamycin having an R t of 16.3 minutes in comparison to rapamycin at 24.6.
EXAMPLE 2
The procedure used in this production of desmethyl analogues is modeled after that described above. A spore stock was used which had been frozen in 0.01% TWEEN 80 (polyethylenesorbitan,) and 10% glycerol. A 0.1 ml aliquot was used to inoculate a seed flask containing 50 ml of seed medium A. The flask was incubated at 27° C. at 220 rpm for 43 hours. Aliquots of 1.0 and 0.1 ml of seed was used to inoculate production flasks containing 34 ml RAP-21, medium, or 25×150 mm tubes containing 3.4 ml RAP-21, respectively. Production tubes and flasks were incubated at 26° C. and 240 rpm. At 32 hours, sinefungin was added to the flasks and tubes such that the final concentration in duplicate flasks was 0.0, 0.5 or 1.0 mM, while that in triplicate tubes was 0.0, 0.25, 0.50, 0.75, or 1.00 mM sinefungin. Flasks and tubes were harvested at 56 hours, and extracted using an equal volume of MeOH and shaken for 30 minutes.
Analysis of the products was accomplished using either a WHATMEN PARTISIL C8 or a WHATMAN PARISIL 5 ODS-3 HPLC column operated at 60 C, and run with a mobile phase of acetonitrile/0.1% H 3 PO 4 operating at 1.0 ml/minute and starting at a ratio of 50/50 and changing to 65/35 in a linear fashion over 20 minutes. Monochromatic detection was carried out at 277 nm and the UV/visible spectra of selected peaks were determined using the WATERS 990 photodiode array detector. The invention had an R t of 18.0 minutes in comparsion to rapamycin at 33.5 minutes.
A partial purification of the control and treated fermentations was accomplished using adsorption onto a C-18 SEP-PAK (WATERS ASSOCIATES) cartridge followed by selective elution of the compounds of interest. The procedure consisted of passing 3.0 ml of fermentation broth that had been extracted with MeOH/H 2 O (1:1) through an activated SEP-PAK cartridge, and then sequentially eluting the compounds of interest first with MeOH/H 2 O of either (75:25) or (8:2) and then pure MeOH. This procedure eliminated most of the very polar materials and served to enrich two of the most polar rapamycin analogues away from some compounds with similar retention times. Elution of the SEP-PAK with MeOH/H 2 O (8:2) afforded material enriched in the invention.
A complete isolation procedure used preliminary to obtaining Mass Spectroscopic identification is as follows:
Step A
Nine hundred ml. of whole broth was filtered using a SUPER-CEL precoat. The mycelia cake was slurried with four hundred ml. of acetone and stirred with good agitation for two hours. The mixture was filtered and the mycelia cake discarded. The acetone filtrate was concentrated to a 50 ml aqueous concentrate and extracted with 3×50 ml of ethyl acetate. The extracts were combined and dried with sodium sulfate. The dried extract was concentrated to dryness.
Step B
The product of step A was taken up in 2.5 ml of ethyl acetate. The solution was chromatographed on 250 ml of E. MERCK silica-gel (0.04 to 0.06 mm) previously equilibrated with ethyl acetate. Chromatograpgy was carried out with ethyl acetate at 8 ml/min collecting a 100 ml forecut followed by one hundred 8 ml fractions. Ninty-eight 8 ml fractions were collected. The solvent was then switched to 97/2.5 v/v ethyl acetate/methanol and ninty-eight 8 ml fractions were collected. The solvent was then switched to 95/5 v/v eth acetate/methanol collecting four 250 ml fractions. Fractions 66 through 198 were combined on the basis of HPLC analysis. A 10% aliquot of the combined fractions was then concentrated to dryness.
Step C
The product of step B was taken up in 75 mcl of methanol and chromatographed on WHATMAN PARTISIL 10 ODS-3 column 0.94×50 cm. at room temperature using a solvent system of 67/33 v/v methanol/water at a flow rate of 4.5 ml./minute. The effluent stream was monitored at 277 nm collecting fractions based on the U.V. trace. Fractions two and three, retention time forty-nine minutes, were combined and concentrated to dryness to yield 1.0 milligrams of the compound of Formula I.
FAB-MS
This material was found to have a molecular weight of 885 as determined by FAB-MS (observed in the lithium spiked spectrum (M+Li) at m/z 892). The EI spectrum exhibits characteristics ions at m/z 175, and 304.
Biological Activity
The biological activity of the rapamycin analogue was assessed by fractionating concentrated eluants from SEP-PAK purification of the sinfungin treated and untreated fermentation extracts. The fractions were neutralized by addition of 50 ul of 0.25M MES per ml eluant, dried on a lyophilizer, and evaluated for antifungal activity in the antifungal assay (AFA), and immunosuppressive activity by a modified version of the T-cell proliferation assay. AFA results are given below in Table 1.
TABLE 1______________________________________Antifungal Activity of Sinefungin Induced RapamycinFermentation ProductsPeak Peak Zone Size (mm)Frac- Rt A. Penicill Ustilago Candida Candidation (Min) niger ium sp. zeae tropical albicans______________________________________1S-17.sup.a 17 0 0 0 11 02S-32.sup.a 32 34 34 25 28 234S-32.sup.b 32 27 23 17 27 185S-17.sup.b 17 28 27 20 23 18______________________________________ .sup.a untreated .sup.b treated
This data indicates that for samples not treated with sinefungin, there is no antifungal activity associated with the 17 minute region of the HPLC chromatograms. However, there is activity associated with the same region in samples that had been treated with sinefungin and the activity was similar in profile to the rapamycin eluted in region 32.
Samples sent for T cell proliferation assay were fractionated in 1.0 minute fractions through the region of interest. The same samples eluted from the SEP-PAKs mentioned above for AFA analysis were also used for the T cell proliferation analysis. The 1.0 ml, 1.0 minute fractions were each neutralized with 50 ul of 0.25M MES, pH 7.3 and evaporated to dryness. In performing the T cell assay the samples were redissolved in 100 ul MeOH at dilutions of 1/100, 1/500, 1/2500 and 1/12500. Samples are considered to be positive in the assay when they give an inhibition level of 50% or greater. The peak at 17-18 minutes was eluted from the SEP-PAK with 80% MeOH. A fractionation of the region for untreated control eluted with 80% methanol was done in addition to the sinefungin treated samples. The T cell proliferation data is summarized in Table 2.
TABLE 2______________________________________T-Cell Proliferation Activity of SinefunginTreated Rapamycin FermentationDILUTION (FRAC. NUMBER)HAVING ACTIVITY .sup.1SAMPLE ACTIVITY (16) (17) (18) (19)______________________________________Control.sup.2 1/100 10 33 33 10Product 1/2500 1 64 74 18______________________________________ .sup.1 only % INHIBITION values greater than 50% are considered active. .sup.2 no sinfungin in fermentation
This table shows that the new peak seen in the 17-18 minute region possesses T-cell proliferation inhibitory activity even diluted out 1 to 2500. The control fractions did not show any activity greater than 50% inhibition even at the highest concentration tested.
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Disclosed is a novel lipophilic macrolide of Formula I: ##STR1## The compound of assigned Formula I is an analog of rapamycin which has activity as an antifungal agent and as an immunosuppressant.
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TECHNICAL FIELD
[0001] This disclosure relates generally to certain pipeline and hose equipment known as dust caps or end caps used in hose lines, pipelines, and pipeline termination racks. More specifically, this disclosure relates to a dust cap or end cap utilized for the quick identification of the contents of the pipeline system when adding or removing fluids from or to hose lines or pipelines.
BACKGROUND
[0002] A wide variety of pipe end caps have been developed in the art. These end caps primarily include screw-type fittings, cam and groove type fittings, and dry-break fittings. The cam and groove type connectors are very popular among conventional pipe equipment used in the mining industry, the petroleum industry, the marine industry, irrigation systems, water treatment works, and power generation facilities. The cam and groove type pipe fittings are designed to easily connect pipelines or any other tubular conduits like hose lines. End caps are designed to prevent the leakage of liquids or gas with their tight connection at the end of hoses and pipes.
[0003] All pipe and hose end caps are designed to prevent fluid leakage, primarily liquid leakage. To prevent leakage or seepage, the end points of pipelines and the hose lines must be tightly sealed. Several methods have been developed for the prevention of leakage at the end of pipes and hose line terminations. End caps have also been employed simply as a protective safety cover. For example, U.S. Pat. No. 5,687,772 issued to Underwood describes a protective end cap for covering the ends of exposed bars and, in particular but not limited to, a protective end cap for covering the ends of starter bars on construction sites.
[0004] Some end caps have been designed to incorporate a “quick release” type feature. U.S. Pat. No. 6,568,430 issued. to Shafer describes quick-release pipe end caps for use in connection with pipes. The quick release pipe end caps have a cap that covers the end of a pipeline and a quick release mechanism that removably secures the cap to the pipeline without requiring the use of other pipefitting tools.
[0005] However, one shortcoming identified with conventional end caps is that they do not provide a means to identify the content of the pipelines. Quick identification of the content of the pipelines is required for filling or removing fluids from a pipeline. It is especially critical when all the end connections are situated in a common bank of multiple pipeline terminations all fitted with end caps. Identification of the contents of the pipeline are important to prevent opening the wrong pipeline to either fill or remove liquid product from the pipeline. There have few attempts to make the identification of the contents of a pipeline easier.
[0006] U.S. Pat. No. 7,644,734 issued to Palmer describes a male and female safety cap to protect the hands of the operator. The male safety cap has a circular disk with a diameter larger than the female fitting and a loop handle. The female safety cap has raised parallel ridges to protect the cam arm and a loop handle. The loop handle forms a continuous arcuate structure to provide protection to the operator's hand. The safety caps are shown to be color coded or affixed with labels designed to fit within the handle. However, this particular end cap design requires a handle that is integral to the end cap in order to affix the product label.
[0007] The end cap devices referenced above provide some desirable features and benefits within the limited scope of their designs. Each has certain benefits and drawbacks, as well, with respect to the fact that they are not effective to identify the contents of a pipeline system or hose line.
[0008] Based on the foregoing, it is desirable to have an end cap that provides liquid leak protection and can be easily applied to identify pipelines or pipeline system contents. This type of end cap would also be available in different sizes, different materials, and different features thereby allowing it to easily fit with any pipeline, hose line, or pipeline termination bank. Finally, this end cap would also be of a simple design that incorporates the invention disclosed herein.
SUMMARY
[0009] Disclosed herein is an end cap that addresses the abovementioned shortcomings with the current end cap devices, especially with respect to the inability to identify the contents of the pipeline. Heretofore, there has not been an end cap for quickly identifying the contents of a pipeline system, hose line, or multiple terminations in a bank of pipeline terminations, while at the same time protecting the pipeline system from fluid leakage and cross-contamination (ie, contamination caused by putting a fluid into a pipeline that is incompatible with the other fluid contents contained in that pipeline).
[0010] The disclosure herein is directed to an end cap designed for quick identification of the contents of hose lines or liquid transport systems while either filling or removing fluids from or to those systems. When several end connections are situated in a common bank of hose line terminations fitted with end caps, it would relatively easy to fill or empty the wrong system when there is no identification of the pipeline that the operator is connecting to for performing the fill or empty operation. There is also disclosed a unique method for providing identification of a pipeline system by applying an identification card into a an end cap that has been designed and fabricated to receive such identification card. Because the identification card is removable, the card can be removed and a new card inserted when the end cap is to be used on a different pipeline.
[0011] While the various embodiments of the disclosure are described with reference to a device for identifying the contents of a pipeline system quickly using an end cap with an identification feature, it is to be understood that there may be combinations of equipment and other methods that could be used to identify the pipeline system. There is no device or apparatus or method with the disclosed features for use in pipeline systems. Other applications and advantages of such an end cap will become immediately obvious to one skilled in the art. It is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.
DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1A is a top view of one embodiment of an end cap of the present invention.
[0013] FIG. 1B is an exploded view of one embodiment of the end cap of the present invention.
[0014] FIG. 1C is a perspective view of one embodiment of the end cap of the present invention.
[0015] FIG. 1D is another perspective view of one embodiment of the end cap of the present invention.
[0016] FIG. 1E is a side view of one embodiment of the end cap of the present invention.
[0017] FIG. 2A is a top view of another embodiment of the end cap of the present invention.
[0018] FIG. 2B is a side view of another embodiment of the end cap of the present invention.
[0019] FIG. 3A is a top view of another embodiment of the end cap of the present invention.
[0020] FIG. 3B is a side view of another embodiment of the end cap of the present invention.
DESCRIPTION
[0021] What is being disclosed is an end cap fabricated and designed to provide identification information of hose and pipeline system contents. Other objects, advantages and applications will be best understood and become apparent from the following description of the various embodiments when read in connection with the accompanying drawings.
[0022] Referring to FIGS. 1A and 1B , the end cap 10 for a pipeline system is shown here in the preferred embodiment of the invention. The end cap 10 is designed for quickly visually identifying contents of hose lines prior to filling or removing liquids from a pipeline system. In the preferred embodiment, the end cap 10 comprises a housing 12 , a plurality of studs 16 and an identification card 20 . The end cap 10 allows quick, visual identification of the contents of hose lines or liquid transport systems while either filling or removing fluids from or to those systems when an identification card 20 is properly inserted into the top surface 14 of the housing 12 .
[0023] As shown in FIG. 1D , the housing 12 comprises a top surface 14 and a bottom portion 36 ( FIG. 1D ). The bottom portion 36 is designed to releasably connect to the hose lines, couplings and, liquid transport fittings employing a cam and groove type engagement mechanism. The housing 12 is preferably cylindrical in shape.
[0024] As shown in FIG. 1B , the top surface 14 comprises a plurality of stud connecting holes 30 . A plurality of studs 16 is designed to be suitably connected to the top surface 14 by engaging the plurality of stud connecting holes 30 . The identification card 20 includes an upper surface 22 and a plurality of matching holes 32 positioned at the upper surface 22 . The identification card 20 is removably attachable to the top surface 14 of the housing 12 by engaging the plurality of studs 16 with the plurality of matching holes 32 .
[0025] As shown in FIG. 1D , the housing 12 further comprises an outer lateral surface 28 and an inner lateral surface 34 . In the preferred embodiment, the outer lateral surface 28 includes a pair of locking arms 24 . Each of the pair of locking arms 24 is opposite to each other. The pair of locking arms 24 allows the end cap 10 to securely engage with the pipeline system that has a complementary matching male end connection (not shown) utilizing the cam and groove type connecting mechanism. The bottom portion 36 is designed to releasably connect to a receiving end portion of a hose and/or a pipe (not shown).
[0026] With reference to FIG. 1C , a perspective view of the preferred embodiment of the end cap 10 is illustrated. The identification card 20 is adaptable to display identification information 26 of the pipeline system. Referring to FIG. 1D again, a perspective view of the preferred embodiment of the end cap 10 showing the inner lateral surface 34 of the end cap 10 is illustrated. The inner lateral surface 34 includes a gasket 38 . The gasket 38 allows the male end portion of a hose and/or a pipe to tightly fit with the inner lateral surface 34 .
[0027] As shown in FIG. 1E , a side view of the preferred embodiment of the end cap 10 is illustrated. The plurality of studs 16 engage with the top surface 14 . Each of the plurality of studs includes a securing element 18 . The securing element 18 may be a machined groove to accept an external snap ring fastener (not shown), a through hole near the top of each of the plurality of studs to accept a cotter pin (not shown), or a threaded rod to accept a complimentary threaded nut (not shown), or a screw that can be inserted into a connecting hole 30 that is tapped to receive a screw connecting mechanism. The securing element 18 allows the identification card 20 to be releasably attached to the top surface 14 of the end cap 10 .
[0028] In use, the plurality of studs 16 is engaged with the plurality of stud connecting holes 30 . The plurality of matching holes 32 positioned at the upper surface 22 of the identification card 20 is engaged with the plurality of studs 16 . Then the identification card 20 is positioned on the top surface 14 of the housing 12 by engagement with the plurality of studs 16 and the securing element 18 . The information 26 on the identification card 20 enables quick identification of the pipelines and hoses attached to the end cap 10 .
[0029] In another embodiment, and with reference to FIGS. 2A and 2B , an end cap 40 comprises a plurality of angle bosses 42 located on the top surface 14 . Each of the plurality of angle bosses 42 includes a lip portion 48 that allows an identification card 20 to securely attach between the plurality of angle bosses 42 . The plurality of angle bosses 42 are fixedly attached to the housing 12 utilizing any suitable attachment mechanism. The attachment of the angle bosses 42 to the top surface 14 may be achieved by casting, welding, or adhesive bonding depending on the material of the housing 12 . In this embodiment, the identification card 20 includes a leading edge to facilitate easy placement of the identification card 20 under the plurality of angle bosses 42 . The identification card 20 possesses an appropriate size, shape and thickness to securely fit between the plurality of angle bosses 42 and below the lip portion 48 . The end cap 40 further comprises a raised stop boss 44 that is intended to prevent the identification card from inadvertently falling through the angle bosses 42 . The raised stop boss 44 engages a bottom portion 46 of the identification card 20 .
[0030] In yet another embodiment, and with reference to FIGS. 3A and 3B , an end cap 50 comprises a cavity area 54 and an identification card 20 with a pair of opposing sides 52 . The cavity area 54 includes at least two retaining lips 56 . The at least two retaining lips 56 allow the identification card 20 to be retained inside the cavity area 54 .
[0031] With reference to FIG. 3B , the cavity area 54 is formed by casting or machining an appropriate area of the top surface 14 and attaching the opposing and overlapping retaining lips 56 utilizing any appropriate attaching mechanism, such as casting, welding, or adhesive bonding.
[0032] Referring specifically to FIG. 3B , there is shown the identification card 20 with the pair of opposing sides 52 inserted beneath the at least two retaining lips 56 located within the cavity area 54 . The at least two retaining lips 56 require the identification card 20 to be slightly flexed in order to position the pair of opposing sides 52 between the at least two retaining lips 56 . The pair of opposing sides 52 extend under the at least two retaining lips 56 . The identification card 20 is thereby releasably attached to the top surface 14 of the end cap 10 .
[0033] The foregoing descriptions provide illustration of the inventive concepts. It should be understood that the foregoing is illustrative of particular embodiments of the invention, and particular applications thereof. The descriptions are not intended to be exhaustive or to limit the disclosed invention to the precise form disclosed. Modifications or variations are also possible in light of the above teachings. In view of the disclosures presented herein, yet other variations of the invention being disclosed will be apparent to one of skill in the art. The embodiments described above were chosen to provide the best application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention. Any such modifications or variations which fall within the purview of the descriptions contained herein are intended to be included therein, as well. It is the following claims, including all equivalents, which define the scope of the invention.
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The disclosure relates to an end cap device for easily identifying a pipeline system. The device is interchangeable among and between pipeline systems. The device is further advantageous in that it is designed to easily fit onto various pipeline, hose line, or pipeline termination banks. The device comprises a housing, and various attachment mechanisms for an interchangeable identification card. The housing includes a top surface, an outer lateral surface, an inner lateral surface and a bottom portion. The identification card includes matching holes to align with the various attachment mechanisms. The identification card is adaptable to visually display identification information about a pipeline system.
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[0001] This application is a continuation-in-part of U.S. Ser. No. 08/620,444, filed Mar. 22, 1996.
[0002] The work described herein was supported in part by a grant from the National Institutes of Health (PO1NS 10828). The government therefore has certain rights in the invention.
[0003] The field of the invention is the treatment of ischemic injury of the central nervous system.
BACKGROUND OF THE INVENTION
[0004] Neurotrophic factors are polypeptides that are required for the development of the nervous system. The first neurotrophic factor discovered, nerve growth factor (NGF), is now known to be a part of a large family of growth factors, which also includes brain-derived neurotrophic factor (BDNF) and the neurotrophins (NT3 and NT4/NT5). Fibroblast growth factors (FGFs) constitute another large family of polypeptide growth factors that induce mitogenic, chemotactic, and angiogenic activity in a wide variety of cells, including neurons (Thomas, FASEB J. 1:434-440, 1987; Burgess et al., Ann. Rev. Biochem. 58:575-606, 1989; Moscatelli et al., U.S. Pat. 4,994,559). While the role of polypeptide growth factors in the developing animal has become increasingly evident, their role in the mature animal, particularly in the nervous system, is much less clear.
[0005] Injury or death of neurons in a mature animal produces motor and/or cognitive deficits that are often permanent. Patients who suffer a “stroke,” or any other form of cerebral ischemic episode, usually recover partially, but often remain mildly to severely debilitated. Currently, aside from physical therapy, there is no treatment that reliably improves the prognosis of a patient who has suffered a cerebral ischemic episode.
SUMMARY OF THE INVENTION
[0006] We have discovered that administration of a polypeptide growth factor provides significant benefits following a cerebral ischemic episode, even when administration occurs a significant amount of time following that episode. Furthermore, functional recovery occurs without a reduction in the size of the infarct (i.e., the necrotic tissue that is produced by ischemia).
[0007] Accordingly, the invention features a method for treating a patient who has suffered an injury to the central nervous system, such as an ischemic episode or a traumatic injury, by administering to the patient a polypeptide growth factor, wherein administration occurs more than six hours after the onset of the injury; administration can beneficially occur even later, i.e., twelve, twenty-four, forty-eight, or more hours following the ischemic episode.
[0008] The polypeptide growth factor administered may be: a member of the fibroblast growth factor (FGF) family, such as basic FGF (bFGF), acidic FGF (aFGF), the hst/Kfgf gene product, FGF-5, or int-2; a member of the neurotrophin family, such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), or neurotrophin 4/5 (NT4/5); an insulin-like growth factor (IGF), such as IGF-1, or IGF-2; ciliary neurotrophic growth factor (CNTF); leukemia inhibitory factor (LIF); oncostatin M; or an interleukin.
[0009] Also included in the invention are “functional polypeptide growth factors,” which possess one or more of the biological functions or activities of the polypeptide growth factors described herein. These functions or activities are described in detail below and concern, primarily, enhancement of recovery following an ischemic event within the central nervous system. Accordingly, alternate molecular forms of polypeptide growth factors are within the scope of the invention. For example, forms of bFGF have been observed with molecular weights of 17.8, 22.5, 23.1, and 24.2 kDa. The higher molecular weight forms being colinear N-terminal extensions of the 17.8 kDa bFGF (Florkiewicz et al., Proc. Natl. Acad. Sci. USA 86:3978-3981, 1989).
[0010] Alternatively, polypeptide growth factors useful in the invention can consist of active fragments of the factors. By “active fragment,” as used herein in reference to polypeptide growth factors, is meant any portion of a polypeptide that is capable of invoking the same activity as the full-length polypeptide. The active fragment will produce at least 40%, preferably at least 50%, more preferably at least 70%, and most preferably at least 90% (including up to 100%) of the activity of the full-length polypeptide. The activity of any given fragment can be readily determined in any number of ways. For example, a fragment of bFGF that, when administered according to the methods of the invention described herein, is shown to produce performance in functional tests that is comparable to the performance that is produced by administration of the full-length bFGF polypeptide, would be an “active fragment” of bFGF. It is well within the abilities of skilled artisans to determine whether a polypeptide growth factor, regardless of size, retains the functional activity of a full length, wild type polypeptide growth factor.
[0011] As used herein, both “protein” and “polypeptide” mean any chain of amino acid residues, regardless of length or post-translational modification (e.g., glycosylation or phosphorylation). The polypeptide growth factors useful in the invention are referred to as “substantially pure,” meaning that a composition containing the polypeptide is at least 60% by weight (dry weight) the polypeptide of interest, e.g., a bFGF polypeptide. Preferably, the polypeptide composition is at least 75%, more preferably at least 90%, and most preferably at least 99%, by weight, the polypeptide of interest. Purity can be measured by any appropriate standard method, e.g., column chromatography, polyacrylamide gel electrophoresis, or HPLC analysis.
[0012] Furthermore, the nomenclature in the field of polypeptide growth factors is complex, primarily because many factors have been isolated independently by different groups of researchers and, historically, named for the type of tissue that was used as an assay in the process of purifying the factor. Basic FGF has been referred to in scientific publications by at least 23 different names. These include leukemic growth factor, macrophage growth factor, embryonic kidney-derived angiogenesis factor 2, prostatic growth factor, astroglial growth factor 2, endothelial growth factor, tumor angiogenesis factor, hepatoma growth factor, chondrosarcoma growth factor, cartilage-derived growth factor 1, eye-derived growth factor 1, heparin-binding growth factors class II, myogenic growth factor, human placenta purified factor, uterine-derived growth factor, embryonic carcinoma-derived growth factor, human pituitary growth factor, pituitary-derived chondrocyte growth factor, adipocyte growth factor, prostatic osteoblastic factor, and mammary tumor-derived growth factor. Thus, any factor referred to by one of the aforementioned names is considered within the scope of the invention.
[0013] The polypeptide growth factors useful in the invention can be naturally occurring, synthetic, or recombinant molecules consisting of a hybrid or chimeric polypeptide with one portion, for example, being bFGF, and a second portion being a distinct polypeptide. These factors can be purified from a biological sample, chemically synthesized, or produced recombinantly by standard techniques (see e.g., Ausubel et al., Current Protocols in Molecular Biology, New York, John Wiley and Sons, 1993; Pouwels et al., Cloning Vectors: A Laboratory Manual, 1985, Supp. 1987).
[0014] The treatment regimen according to the invention is carried out, in terms of administration mode, timing of the administration, and dosage, so that the functional recovery of the patient from the adverse consequences of the central nervous system injury is improved; i.e., the patient's motor skills (e.g., posture, balance, grasp, or gait), cognitive skills, speech, and/or sensory perception (including visual ability, taste, olfaction, and proprioception) improve as a result of polypeptide growth factor administration according to the invention.
[0015] Administration of polypeptide growth factors according to the invention can be carried out by any known route of administration, including intravenously, orally, or intracerebrally (e.g., intraventricularly, intrathecally, or intracisternally); intracisternal administration can be carried out, e.g., using 0.1 to 100 μg/kg/injection and administering a single injection or a series of injections. For example, intracisternal administration can consist of a single injection given, for example, 24 hours after an injury, a pair of injections, given, for example, 24 and 48 hours after an injury, or, if necessary, a series of injections of, for example, 3.0 μg/kg/injection, given biweekly (for example, every 3-4 days) in a treatment regimen that occurs twenty-four hours or longer following the ischemic episode. The treatment regimen may last a number of weeks. Alternatively, intracisternal administration can consist of a series of injections, at 1.5 μg/kg/injection, given once, twice, or, for example, biweekly in a treatment regimen that occurs twenty-four hours or longer following the ischemic episode.
[0016] Alternatively, the polypeptide growth factors can be administered intravenously. Typically, the dosage for intravenous administration will be greater than that for intracisternal administration, e.g., 10 to 1,000 μg/kg of a polypeptide growth factor may be administered. Preferably, the polypeptide growth factors are administered intravenously at concentrations ranging from 1-100 μg/kg/hour. Treatment regimes are discussed in detail below.
[0017] The invention can be used to treat the adverse consequences of central nervous system injuries that result from any of a variety of conditions. Thrombus, embolus, and systemic hypotension are among the most common causes of cerebral ischemic episodes. Other injuries may be caused by hypertension, hypertensive cerebral vascular disease, rupture of an aneurysm, an angioma, blood dyscrasias, cardiac failure, cardic arrest, cardiogenic shock, septic shock, head trauma, spinal cord trauma, seizure, bleeding from a tumor, or other blood loss.
[0018] Where the ischemia is associated with a stroke, it can be either global or focal ischemia, as defined below. It is believed that the administration of polypeptide growth factors according to the invention is effective, even though administration occurs a significant amount of time following the injury, at least in part because these peptides stimulate the growth of new processes from neurons. In addition, polypeptide growth factors may protect against retrograde neuronal death, i.e., death of the neurons that formed synapses with those that died in the area of the infarct.
[0019] By “ischemic episode” is meant any circumstance that results in a deficient supply of blood to a tissue. Cerebral ischemic episodes result from a deficiency in the blood supply to the brain. The spinal cord, which is also a part of the central nervous system, is equally susceptible to ischemia resulting from diminished blood flow. An ischemic episode may be caused by a constriction or obstruction of a blood vessel, as occurs in the case of a thrombus or embolus. Alternatively, the ischemic episode can result from any form of compromised cardiac function, including cardiac arrest, as described above. It is expected that the invention will also be useful for treating injuries to the central nervous system that are caused by mechanical forces, such as a blow to the head or spine. Trauma can involve a tissue insult such as an abrasion, incision, contusion, puncture, compression, etc., such as can arise from traumatic contact of a foreign object with any locus of or appurtenant to the head, neck, or vertebral column. Other forms of traumatic injury can arise from constriction or compression of CNS tissue by an inappropriate accumulation of fluid (for example, a blockade or dysfunction of normal cerebrospinal fluid or vitreous humor fluid production, turnover, or volume regulation, or a subdural or intracranial hematoma or edema). Similarly, traumatic constriction or compression can arise from the presence of a mass of abnormal tissue, such as a metastatic or primary tumor.
[0020] By “focal ischemia,” as used herein in reference to the central nervous system, is meant the condition that results from the blockage of a single artery that supplies blood to the brain or spinal cord, resulting in the death of all cellular elements (pan-necrosis) in the territory supplied by that artery.
[0021] By “global ischemia,” as used herein in reference to the central nervous system, is meant the condition that results from a general diminution of blood flow to the entire brain, forebrain, or spinal cord, which causes the death of neurons in selectively vulnerable regions throughout these tissues. The pathology in each of these cases is quite different, as are the clinical correlates. Models of focal ischemia apply to patients with focal cerebral infarction, while models of global ischemia are analogous to cardiac arrest, and other causes of systemic hypotension.
[0022] The method of the invention has several advantages. First, polypeptide growth factors can be administered hours, days, weeks, or even months following an injury to the central nervous system. This is advantageous because there is no way to anticipate when such an injury will occur. All of the events that cause ischemia or trauma, as discussed above, are unpredictable. Second, the therapeutic regimen improves functional performance without adverse side effects.
[0023] All publications, patents, patent applications, and other references cited herein are incorporated by reference in their entirety.
[0024] The preferred methods, materials, and examples that will now be described are illustrative only and are not intended to be limiting; materials and methods similar or equivalent to those described herein can be used in the practice or testing of the invention. Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Note that in FIGS. 2 A- 2 B and 3 A- 3 B, the scores representing performance of rats treated with a total of 8 μg of bFGF are depicted along the y-axis with lower scores, representing better performance, nearest the intersection with the X-axis. In contrast, in FIGS. 5 A- 5 B and 6 A- 6 B, the scores representing performance of rats treated with a total of 4 μg of bFGF are depicted along the y-axis with lower scores, representing better performance, furthest from the intersection with the X-axis. The change from the former to the latter presentation was made so that improvement would appear as an upward trend, rather than a downward trend.
[0026] n.s.=non-significant.
[0027] FIGS. 1 A- 1 F are a series of photographs of brain sections stained with hemotoxylin and eosin. A representative cerebral infarct, produced following proximal middle cerebral artery (MCA) occlusion, is shown. Coronal sections are +4.7 (FIG. 1A), +2.7 (FIG. 1B), +0.7 (FIG. 1C), −1.3 (FIG. 1D), −3.3 (FIG. 1E), and −5.3 (FIG. 1F) compared to bregma.
[0028] FIGS. 2 A- 2 B are a pair of graphs depicting forelimb placing ( 2 A) and hindlimb placing ( 2 B) scores of affected (left) limbs of bFGF-treated animals (3 μg/kg/injection; total bFGF delivered=8 μg/animal; N=9 animals; closed squares) and vehicle-treated animals (N=8, open squares). Data are means±SD. ANOVA (forelimb placing): treatment: F(1)=17.7, p=0.0008. ANOVA (hindlimb placing): treatment: F(1)=26.0, p=0.0001. *=values in bFGF-treated animals different from corresponding values in vehicle-treated animals by two-tailed unpaired t-tests with Bonferroni correction (p<0.05).
[0029] FIGS. 3 A- 3 B are a pair of graphs depicting balance beam ( 3 A) and postural reflex ( 3 B) scores in bFGF treated animals (3 μg/kg/injection; total bFGF delivered=8 μg/animal; N=9 animals; closed squares) and vehicle-treated animals (N=8 animals, open squares). Data are means±SD. ANOVA (beam balance): treatment: F(1)=7.5, p=0.02. ANOVA (postural reflex): treatment: F(1)=7.2, p=0.02. *=values in bFGF-treated animals different from corresponding values in vehicle-treated animals by two-tailed unpaired t-tests with Bonferroni correction (p<0.05).
[0030] [0030]FIG. 4 is a graph depicting body-weight in bFGF-treated animals (3 μg/kg/injection; total bFGF delivered=8 μg/animal; N=9 animals; closed squares) and vehicle-treated animals (N=8 animals; open squares). Data are means±SD. ANOVA: treatment F(1)=2.8, p=n.s.
[0031] FIGS. 5 A- 5 B are a pair of graphs depicting forelimb placing ( 5 A) and hindlimb placing ( 5 B) scores of affected (left) limbs of low dose (LD) bFGF-treated animals (1.5 μg/kg/injection; total bFGF delivered=4 μg/animal; N=8 animals; closed squares) and vehicle-treated animals (N=6 animals; open squares). Data are means±SEM. ANOVA (forelimb placing): treatment: F(1)=32.65, p=0.0001. ANOVA (hindlimb placing): treatment: F(1)=34.58, p=0.0001.
[0032] FIGS. 6 A- 6 B are a pair of graphs depicting beam balance ( 6 A) and postural reflex ( 6 B) scores in low dose bFGF-treated animals (1.5 μg/kg/injection; total bFGF delivered=4 μg/animal; N=8 animals; closed squares) and vehicle-treated animals (N=6, open squares). Data are means±SEM. ANOVA (beam balance): treatment F(1)=15.933, p=0.0018. ANOVA (postural reflex): treatment: F(1)=1.998, p=n.s.
[0033] [0033]FIG. 7 is a graph demonstrating that there was no difference between the body weight of animals that received low dose bFGF intracisternally (total bFGF delivered=4 μg/animal; N=8 animals; closed squares), animals that received vehicle intracisternally (N=6; open squares; Data are means±SEM. ANOVA: treatment: F(1)=3.02, p=n.s.), animals that received bFGF intravenously (closed circles), and animals that received vehicle intravenously (open circles).
[0034] FIGS. 8 A- 8 B are a pair of graphs depicting forelimb placing ( 8 A) and hindlimb placing ( 8 B) scores of affected (left) limbs of animals treated by intravenous injection of bFGF (at 50 μg/kg/hour for 3 hours; see closed circles) or of animals treated by intravenous injection of vehicle alone (see open circles). These data are presented along with that obtained from animals that received intracisternal injections of bFGF biweekly (at 0.5 μg/kg/injection, i.e., low dose bFGF-treated animals) to show that recovery is comparable.
[0035] FIGS. 9 A- 9 E are a series of photographs from an image analyzer (FIGS. 9 A- 9 D) and a schematic drawing (FIG. 9E) of histological sections of rat brain (anterior to bregma) stained for GAP-43 immunoreactivity following surgical induction of stroke and intracisternal bFGF treatment. Anterior sections were collected from a sham-operated/vehicle-treated animal (FIG. 9A), a stroke-induced/vehicle-treated animal (FIG. 9B), a sham-operated/bFGF-treated animal (FIG. 9C), and a stroke-induced/bFGF-treated animal (FIG. 9D). The darker regions represent regions of GAP-43 immunoreactivity where the optical density was 1.5 times or greater compared to that in the corpus callosum in each slice. Curved arrows point to cerebral infarcts. Various brain regions are shown in the schematic diagram (FIG. 9E): Cg=cingulate cortex; FR 1,2=frontal cortex, areas 1 and 2; FL=forelimb are; Par 1,2=parietal cortex, areas 1 and 2; I=insular cortex; Pir=piriform cortex; CC=corpus callosum; Sep=septal nucleus; CP=caudoputamen.
[0036] FIGS. 10 A- 10 E are a series of photographs from an image analyzer (FIGS. 10 A- 10 D) and a schematic drawing (FIG. 10E) of histological sections of rat brain (posterior to bregma) stained for GAP-43 immunoreactivity following surgical induction of stroke and intracisternal bFGF treatment. Posterior sections were collected from a sham-operated/vehicle-treated animal (FIG. 10A), a stroke-induced/vehicle-treated animal (FIG. 10B), a sham-operated/bFGF-treated animal (FIG. 10C), and a stroke-induced/bFGF-treated animal (FIG. 10D). The darker regions represent regions of GAP-43 immunoreactivity where the optical density was 1.5 times or greater compared to that in the corpus callosum in each slice. Curved arrows point to cerebral infarcts (in FIG. 10B all necrotic tissue has fallen off the slide; in FIG. 10D some infarcted tissue remains (lower curved arrow), but is necrotic as determined by hemotoxylin and eosin staining of adjacent sections. Various brain regions are shown in the schematic diagram (FIG. 10E): Rs=retrosplenial cortex; FR 1,2=frontal cortex, areas 1 and 2; HL=hindlimb area; Parl, 2=parietal cortex, areas 1 and 2; Prh=perirhinal cortex; Pir=piriform cortex; Am=amygdala; CP=caudoputamen; H=hippocampus; Hy=hypothalamus.
DETAILED DESCRIPTION
[0037] To develop a method for treating a patient following brain and/or spinal cord injury, the polypeptide growth factor basic FGF (bFGF) was administered to animals following occlusion of the middle cerebral artery (MCA). Occlusion of the MCA is a well accepted model of a focal ischemic episode and is thought to mimic the events that occur in humans following a stroke. Animals that were treated with bFGF, beginning 24 hours after occlusion of the MCA, performed significantly better than untreated animals in a variety of functional/behavioral tests.
[0038] The means by which a polypeptide growth factor can be administered to a patient who has suffered an ischemic attack within the central nervous system are first described and are followed by particular examples in which bFGF was administered either intracisternally or intravenously and shown to enhance recovery from surgically induced focal brain ischemia.
[0039] Polypeptide growth factors can be administered to a patient at therapeutically effective doses as follows. A therapeutically effective dose refers to a dose that is sufficient to result in functional recovery, beyond that which would be expected without administration of the polypeptide.
Effective Dose
[0040] Toxicity and therapeutic efficacy of a given polypeptide growth factor can be determined by standard pharmaceutical procedures, using either cells in culture or experimental animals to determine the LD 50 (the dose lethal to 50% of the population) and the ED 50 (the dose therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index, and it can be expressed as the ratio LD 50 :ED 50 . Polypeptides that exhibit large therapeutic indices are preferred. While polypeptide growth factors that exhibit toxic side effects can be used, care should be taken to design a delivery system that targets such compounds to the site of affected tissue in order to minimize potential damage to unaffected cells and, thereby, reduce side effects.
[0041] The data obtained from cell culture assays and animal studies, notably the studies of rats described below, can be used in formulating a range of dosage for use in humans. The dosage of such polypeptides lies preferably within a range of circulating concentrations that include the ED 50 with little or no toxicity. The dosage can vary within this range depending upon the dosage form employed and the route of administration utilized. For any polypeptide used in the method of the invention, the therapeutically effective dose can be estimated initially from the studies of surgically induced ischemia in the mammalian brain that are described below.
[0042] A dose can be formulated in animal models to achieve a circulating plasma concentration range that includes the IC 50 (that is, the concentration of the test polypeptide which achieves a half-maximal induction of recovery) as determined in the in vivo studies described below. Such information can be used to more accurately determine useful doses in humans. Levels in plasma can be measured, for example, by radioimmunoassay (RIA).
Formulations and Use
[0043] Pharmaceutical compositions for use in accordance with the present invention can be formulated in a conventional manner using one or more physiologically acceptable carriers or excipients.
[0044] Thus, the polypeptide growth factors can be formulated for administration by inhalation or insufflation (either through the mouth or the nose) or oral, buccal, parenteral, or rectal administration.
[0045] For oral administration, the pharmaceutical compositions can take the form of, for example, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (for example, pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); fillers (for example, lactose, microcrystalline cellulose or calcium hydrogen phosphate); lubricants (for example, magnesium stearate, talc or silica); disintegrants (for example, potato starch or sodium starch glycolate); or wetting agents (for example, sodium lauryl sulphate). The tablets can be coated by methods well known in the art. Liquid preparations for oral administration can take the form of, for example, solutions, syrups or suspensions, or they can be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations can be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (for example, sorbitol syrup, cellulose derivatives or hydrogenated edible fats); emulsifying agents (for example, lecithin or acacia); non-aqueous vehicles (for example, almond oil, oily esters, ethyl alcohol or fractionated vegetable oils); and preservatives (for example, methyl or propyl-p-hydroxybenzoates or sorbic acid). The preparations can also contain buffer salts, flavoring, coloring, and sweetening agents as appropriate.
[0046] Preparations for oral administration can be suitably formulated to give controlled release of the active compound.
[0047] For buccal administration the compositions can take the form of tablets or lozenges formulated in conventional manner.
[0048] The polypeptide growth factors can be formulated for parenteral administration by injection, for example, by boles injection or continuous infusion. Formulations for injection can be presented in unit dosage form, for example, in ampules or in multi-dose containers, with an added preservative. The compositions can take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and can contain formulatory agents such as suspending, stabilizing, and/or dispersing agents. Alternatively, the active ingredient can be in powder form for constitution with a suitable vehicle, for example, sterile pyrogen-free water, before use.
[0049] The polypeptide growth factors can also be formulated in rectal compositions such as suppositories or retention enemas, for example, containing conventional suppository bases such as cocoa butter or other glycerides.
[0050] In addition to the formulations described previously, the compounds can also be formulated as a depot preparation. Such long acting formulations can be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection. Thus, for example, the compounds can be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.
[0051] The polypeptide growth factors can, if desired, be presented in a pack or dispenser device which can contain one or more unit dosage forms containing the active ingredient. The pack can, for example, comprise metal or plastic foil, such as a blister pack. The pack or dispenser device can be accompanied by instructions for administration.
[0052] The therapeutic polypeptide growth factors of the invention can also contain a carrier or excipient, many of which are known to skilled artisans. Excipients which can be used include buffers (for example, citrate buffer, phosphate buffer, acetate buffer, and bicarbonate buffer), amino acids, urea, alcohols, ascorbic acid, phospholipids, proteins (for example, serum albumin), EDTA, sodium chloride, liposomes, mannitol, sorbitol, and glycerol. The nucleic acids, polypeptides, antibodies, or modulatory compounds of the invention can be administered by any standard route of administration. In addition to the routes of administration described above, the polypeptide growth factor can be administered intravenously, intraarterially, subcutaneously, intramuscularly, intracranially, intraorbitally, opthalmically, intraventricularly, intracapsularly, intraspinally, or intracisternally.
[0053] The polypeptide growth factor can be formulated in various ways, according to the corresponding route of administration. For example, liquid solutions can be made for ingestion or injection; gels or powders can be made for ingestion, inhalation, or topical application. Methods for making such formulations are well known and can be found in, for example, “Remington's Pharmaceutical Sciences” (A. Gennaro, Ed., Mack Publ., 1990). It is expected that the preferred route of administration will be intravenous. It is known that bFGF administered intravenously crosses the damaged blood brain barrier to enter ischemic brain tissue (Fisher et al., J. Cereb. Blood Flow Metab. 15:953-959, 1995; Huang et al., Amer. J. Physiol. in press).
[0054] It is well known in the medical arts that dosages for any one patient depend on many factors, including the general health, sex, weight, body surface area, and age of the patient, as well as the particular compound to be administered, the time and route of administration, and other drugs being administered concurrently. Determining the most appropriate dosage and route of administration is well within the abilities of a skilled physician.
Experimental Reagents and Procedures
Surgical Occlusion of the Middle Cerebral Artery
[0055] The animal model of ischemia used herein is the middle cerebral artery (MCA) occlusion model, which is a focal ischemia model (Kawamata et al., J. Cereb. Blood Flow Metab., 16:542-547, 1996; Gotti et al., Brain Res. 522:290-307, 1990). The animals used in this study were male Sprague-Dawley rats weighing 250-300 grams (Charles River). For surgical procedures, the animals were anesthetized with 2% halothane in 70% NO 2 /30% O 2 The tail artery was cannulated to enable blood gas and blood glucose monitoring. Body temperature was monitored using a rectal probe and was maintained at 37+0.5° C. with a heating pad. The proximal right middle cerebral artery (MCA) was occluded permanently using a modification of the method of Tamura et al. ( J. Cereb. Blood Flow Metab. 1:53-60, 1981). Briefly, the proximal MCA was exposed transcranially without removing the zygomatic arch or transecting the facial nerve. The artery was then electrocoagulated using a bipolar microcoagulator from just proximal to the olfactory tract to the inferior cerebral vein, and was then transected (Bederson et al., Stroke 17:472-476, 1986). Rats were observed until they regained consciousness and were then returned to their home cages. Cefazolin sodium (40 mg/kg, i.p.), an antibiotic, was administered to all animals on the day before and just after stroke surgery in order to prevent infection.
Administration of Polyeptide Growth Factors
[0056] Recombinant human bFGF was obtained as a concentrated stock (2 mg/ml; Scios Nova Corp, Mountain View, Calif.), and stored at −80° C. In preparation for use, the stock solution was diluted with 0.9% saline containing 100 μg/ml bovine serum albumin (BSA; Boehringer-Mannheim, Cat. #711454), pH 7.4, to give a final bFGF concentration of 20 μg/ml. Control animals received solutions without bFGF but with all other components at the same final concentration.
Intracisternal Administration
[0057] For intracisternal injections, most animals were placed in one of two treatment groups: one group of animals received a dose of 3 μg/kg/injection (“high dose bFGF”), and a second group of animals received a dose of 1.5 μg/kg/injection (“low dose bFGF”). To administer the injection, the animals were anesthetized with halothane in 70% NO 2 /30% O 2 and placed in a stereotaxic frame. The procedure for intracisternal injection of growth factor-containing solutions or vehicle-only solutions was identical.
[0058] The following is a description of intracisternal administration, as performed with “high dose” bFGF. Using aseptic technique, bFGF (N=9 animals at 3 μg/kg/injection; N=8 animals at 1.5 μg/kg/injection ) or vehicle only (N=8 animals in the “high dose” bFGF study; N=6 animals in the “low dose” bFGF study) were introduced by percutaneous injection (50 μl/injection) into the cisterna magna using a Hamilton syringe fitted with a 26 gauge needle (Yamada et al., J. Cereb. Blood Flow Metab. 11:472-478, 1991). Before each injection, 1-2 μl of cerebrospinal fluid (CSF) was drawn back through the Hamilton syringe to verify needle placement in the subarachnoid space. Preliminary studies demonstrated that a dye, 1% Evans blue, delivered in this fashion diffused freely through the basal cisterns and over the cerebral cortex within one hour of injection.
[0059] Intracisternal injections were made biweekly for four weeks, starting 24 hours after stroke (i.e., on post-stroke days 1, 4, 8, 11, 15, 18, 22, and 25). Animals were randomly assigned to either of the bFGF treatment groups, or to the vehicle treatment group.
[0060] A third group of animals received only two intracisternal injections of bFGF, at 0.5 μg/injection on the first and second days after stroke. Since the average weight of a rat is 300-400 grams, an equivalent dosage per weight, would be 1.5 μg/kg/injection. These injections were administered as described above. Control animals were matched to this treatment group as well, and received solutions without bFGF but with all other components at the same final concentration on the first and second days after stroke.
Intravenous Administration
[0061] bFGF was prepared as described above (i.e., by dissolving in 0.9% saline with 100 μg/ml BSA) so that the final concentration was 30 μg/ml. The bFGF was then administered to rats intravenously at a rate of 50 μg/kg/hour for three hours. Administration occurred one day after MCA occlusion. Control animals were treated with an intravenous infusion that lacked bFGF, but otherwise contained the same constituents that were in the infusion received by the bFGF-treated animals.
Functional/Behavioral Testing
[0062] To accustom the animals to handling, which would be necessary for behavioral/functional testing, they were handled for three days before surgery, for 10 minutes each day. Following surgery, they were housed in individual cages.
[0063] Four functional/behavioral tests were used to assess sensorimotor and reflex function after infarction. The full details of these tests have been described elsewhere (Bederson et al., Stroke 17:472-476, 1986; DeRyck et al., Brain Res. 573:44-60, 1992; Markgraf et al., Brain Res. 575 : 238 -246, 1992; Alexis et al., Stroke 26:2338-2346, 1995).
The Forelimb Placing Test
[0064] Briefly, the forelimb placing test is comprised of three subtests. Separate scores are obtained for each forelimb. For the visual placing subtest, the animal is held upright by the researcher and brought close to a table top. Normal placing of the limb on the table is scored as “0,” delayed placing (<2 sec) is scored as “1,” and no or very delayed placing (>2 sec) is scored as “2.” Separate scores are obtained first as the animal is brought forward and then again as the animal is brought sideways to the table (maximum score per limb=4; in each case higher numbers denote greater deficits). For the tactile placing subtest, the animal is held so that it cannot see the table top or touch it with its whiskers. The dorsal forepaw is touched lightly to the table top as the animal is first brought forward and then brought sideways to the table. Placing each time is scored as above (maximum score per limb=4). For the proprioceptive placing subtest, the animal is brought forward only and greater pressure is applied to the dorsal forepaw; placing is scored as above (maximum score per limb=2). These subscores are added to give the total forelimb placing score per limb (range=0-10).
The Hindlimb Placing Test
[0065] The hindlimb placing test is conducted in the same manner as the forelimb placing test but involves only tactile and proprioceptive subtests of the hindlimbs (maximal scores 4 and 2, respectively; total score range=0-6).
The Modified Balance Beam Test
[0066] The modified balance beam test examines vestibulomotor reflex activity as the animal balances on a long, narrow beam (30×1.3 cm) for 60 seconds. Ability to balance on the beam is scored as follows: 1=animal balances with all four paws on top of beam; 2=animal puts paws on side of beam or wavers on beam; 3=one or two limbs slip off beam; 4=three limbs slip off beam; 5=animal attempts to balance with paws on beam but falls off; 6=animal drapes over beam, then falls off; 7=animal falls off beam without an attempt to balance. Animals received three training trials before surgery: the score of the last of these was taken as the baseline score.
The Postural Reflex Test
[0067] The postural reflex test measures both reflex and sensorimotor function. Animals are first held by the tail suspended above the floor. Animals that reach symmetrically toward the floor with both forelimbs are scored “0.” Animals showing abnormal postures (flexing of a limb, rotation of the body) are then placed on a plastic-backed sheet of paper. Those animals able to resist side-to-side movement with gentle lateral pressure are scored “1,” while those unable to resist such movement are scored “2.” All functional/behavioral tests were administered just before stroke surgery and then every other day from post-stroke day 1 to post-stroke day 31. At each session, animals were allowed to adapt to the testing room for 30 minutes before testing was begun.
Histological Analysis
[0068] On post-stroke day 31 (i.e. 31 days after MCA occlusion), animals were anesthetized deeply with pentobarbital and perfused transcardially with heparinized saline followed by 10% buffered formalin. Brains were removed, cut into three pieces, and stored in 10% buffered formalin before dehydration and embedding in paraffin. Coronal sections (5 μm) were cut on a sliding microtome, mounted onto glass slides, and stained with hematoxylin and eosin. The area of cerebral infarcts on each of seven slices (+4.7, +2.7, +0.7, −1.3, −3.3, −5.3, and −7.3 compared to bregma) was determined using a computer-interfaced imaging system (Bioquant, R&M Biometnix, Inc., Nashville, Tenn.). Total infarct area per slice was determined by the “indirect method” as [the area of the intact contralateral hemisphere]−[the area of the intact ipsilateral hemisphere] to correct for brain shrinkage during processing (Swanson et al., J. Cereb. Blood Flow Metab. 10:290-293, 1990). Infarct volume was then expressed as a percentage of the intact contralateral hemispheric volume. The volumes of infarction in cortex and striatum were also determined separately using these methods.
[0069] The experimenter performing intracisternal injections, behavioral testing, and histological analysis was blinded to the treatments assigned until all data had been collected. Data were expressed as means±SD or means±SEM and were analyzed by repeated measures analysis of Variance (ANOVA) followed by appropriate unpaired two-tailed t-tests, with the Bonferroni correction for multiple comparisons.
Immunostaining for Growth Associated Protein-43
[0070] Growth Associated Protein-43 (GAP-43) is a phosphoprotein component of the neuronal membrane and growth cone that is selectively upregulated during new axonal growth in both the peripheral and central nervous systems (Skene, Ann. Rev. Neurosci. 12:127-156, 1989; Aigner et al., Cell 83:269-278, 1995; Woolf et al., Neuroscience 34:465-478, 1990; Benowitz et al., Mol. Brain Res. 8:17-23, 1990). GAP-43 has been used as a reliable marker of new axonal growth during brain development, and following brain injury or ischemia (Stroemer et al., Stroke 26:2135-2144, 1995; Benowitz et al. supra; Vaudano et al., J. Neurosci. 15:3594-3611, 1995). GAP-43 immunoreactivity (IR) was examined in animals with focal infarcts (produced by MCA occlusion as described above) that either received or did not receive intracisternal bFGF. Animals that received bFGF were given 0.5 μg/injection, beginning at 24 hours after the infarction. Injections continued biweekly for four weeks, or until the animals was sacrified.
[0071] For histological analysis, animals were killed 3, 7, or 14 days post-stroke surgery (by MCA occlusion) by transcardial perfusion fixation with normal saline followed by 2% formaldehyde, 0.01 M sodium-m-periodate, and 0.075 M L-lysine monohydrochloride in 0.1 M sodium phosphate buffer (pH 7.4; PLP solution). Their brains were removed, post-fixed, and cut into 40 μm sections on a vibratome. The sections were cryoprotected.
[0072] Free-floating sections were successively incubated in 20% normal goat serum, a mouse monoclonal antibody to GAP-43 (1:500, clone 91El2, Boehringer-Mannheim, Indianapolis, Ind.), and biotinylated horse anti-mouse IgG adsorbed against rat IgG (45 μl/ 10 ml; Vector, Burlingame, Calif.). Sections were then mounted onto glass slides, air dried, immersed in gradient ethanol, and coverslipped. Brain sections from all animals at each time point (i.e., animals sacrificed 3, 7, or 14 days post-stroke surgery) were immunostained simultaneously. Control sections were processed without primary antibody and showed no specific staining.
[0073] Following immunostaining, two standard coronal sections through the cerebral infarcts were examined; an “anterior” section at +0.2 mm compared to bregma and a “posterior” section at 02.8 mm compared to bregma. The relative changes in the intensity and extent of GAP-43 immunoreactivity (IR) were quantified using a computer-interfaced imagining system (Bioquant, Nashville, Tenn.) by two different methods. Adjacent brain sections, stained with hemotoxylin and eosin by standard procedures, were used to identify the extent of the infarct. The optical density (O.D.) of a region of reliably low GAP-43 IR (the corpus callosum) was considered the “background” value for each section.
[0074] Measurements were made in two ways. In one way, all brain regions showing an O.D. of at least 1.5 times the O.D. of the background were identified and highlighted (FIGS. 9 A- 9 D and FIGS. 10 A- 10 D). The area (in mm 2 ) of highlighted regions in the dorsolateral sensorimotor cortex was determined for each slice, and averaged among animals in each group. In the second way, specific regions of dorsolateral sensorimotor cortex were identified using a published standard rat brain atlas (Paxinos and Watson, “The Rat Brain in Stereotaxic Coordinates,” Academic Press, San Diego, Calif.). On “anterior” brain sections, these included the medial peri-infarct cortex (≦1 mm from the infarct border) in the ipsilateral hemisphere, and frontal cortex areas 1 and 2 (FR 1,2) and forelimb area of cortex (FL) regions in both hemispheres (FIGS. 9 A- 9 E). On “posterior” sections, these included the medial peri-infarct region in the ipsilateral hemisphere, as well as FR 1,2 and hindlimb area of cortex (HL) regions bilaterally (FIGS. 10 A- 10 E). The O.D. was determined for each region on each section and normalized to background. For each method, data in sham or vehicle-treated and data in sham or bFGF-treated animals were not different, so these values were pooled in the analysis. Data in all groups were expressed as ratios compared to stroke/vehicle-treated animals.
Results
There was no Difference in Total Infarct Volume Between bFGF-Treated, or Vehicle-Treated Animals
[0075] During stroke surgery, there were no differences in the levels of blood gases or glucose among animals that subsequently received bFGF or vehicle treatment. Among surviving animals, sacrifice at day 31 showed large infarcts in the right lateral cerebral cortex and underlying striatum in the territory of the MCA (FIG. 1). Brain regions severely damaged by infarcts included parietal cortex, areas 1 and 2 (Par1, Par2) and granular insular cortex (GI). Regions partially damaged by infarcts included frontal cortex, areas 1, 2, and 3 (FR1, FR2, FR3); agranular insular cortex (Al); temporal cortex, areas 1 and 3 (Tel1, Tel3); lateral occipital cortex, area 2 (Oc2L); the cortical forelimb area (FL), and the caudoputamen (cPu; Paxinos and Watson, 1986). The cortical hindlimb area (HL) was generally spared from infarcts.
[0076] There was no difference in total infarct volume between animals treated with 3 μg/kg/injection of bFGF (“high dose” bFGF) and vehicle-treated animals (31.1±5.9 vs. 30.0±5.3% of intact contralateral hemispheric volume, N=9 vs. N=8, respectively, t=0.4, p=n.s.). Similarly, there was no difference in total infarct volume between animals treated with 1.5 μg/kg/injection of bFGF (“low dose” bFGF), or vehicle-treated animals. Moreover, there was no difference in cortical or striatal infarct volume among the growth factor-treated animals and the vehicle-treated animals, when these volumes were calculated separately.
[0077] Inspection of hematoxylin and eosin-stained sections showed no evidence of abnormal cell proliferation in the brains of bFGF-treated animals.
Animals Treated with bFGF Performed Better than Animals Treated with Vehicle in Functional Tests
[0078] Following infarction, animals showed severe disturbances of sensorimotor and reflex function on all four behavioral tests. For the limb placing tests, deficits were confined to the contralateral (left) limbs. Animals showed partial recovery on all four behavioral tests during the first month after stroke (FIGS. 2 A- 2 B and FIGS. 3 A- 3 B). Moreover, bFGF-treated animals recovered more rapidly and to a greater degree than vehicle-treated rats. Improved recovery of surviving bFGF- vs. vehicle-treated animals was most pronounced for the forelimb and hindlimb placing tasks, and less pronounced, although still significant, for the beam balance and postural reflex tests. See FIGS. 2 A- 2 B and FIGS. 3 A- 3 B for the performance of animals in the four behavioral tests performed after receiving “high” doses of bFGF intracisternally, and FIGS. 5 A- 5 B and FIGS. 6 A- 6 B for the performance of animals in the four behavioral tests performed after receiving “low” doses of bFGF intracisternally. Enhanced recovery was seen on all subtests of the limb placing tests (visual, tactile, and proprioceptive) following bFGF treatment.
[0079] Five of the 14 animals that were treated with the higher dose of bFGF, i.e., with 3 μg/kg/injection, experienced severe progressive weight loss during the first month after stroke and died. The performance of these animals was comparable to that of surviving bFGF-treated animals until the time of their death at 7-23 days after stroke. The mean weight of animals that were treated with 3 μg/kg/injection of bFGF and that died was 165±11 g on the day of death. The animals that were treated with this same dose, but survived, exhibited a small degree of initial weight loss followed by a gradual recovery of body weight after stroke (FIG. 4). Survival of bFGF-treated animals tended to recover body weight more slowly than vehicle-treated rats (FIG. 4). In contrast, animals treated with a lower dose of bFGF, i.e., 1.5 μg/kg/injection were no different in weight than animals that were treated with vehicle only. The animals that received a lower dose of bFGF did not experience the weight loss incurred at the higher dosage; their weight was the same as that of the vehicle-only treated animals (FIG. 7), and they performed better than vehicle-treated animals in both forelimb and hindlimb placing tests (FIGS. 5 A- 5 B).
[0080] The recovery of animals that were given only 2 injections of bFGF (i.e. 0.5 μg/injection of bFGF on the first and second days after stroke) was comparable to the recovery of animals that were given 8 injections of bFGF (i.e., biweekly injections of either “high” or “low” dose bFGF for one month). For example, by 30 days after the stroke, the average score in the forelimb placing test of animals given 8 biweekly intracisternal injections (of either 3 or 1.5 μg/kg/injection) of bFGF was approximately “2,” as was the average score of the animals given intracisternal injections (of 1.5 μg/kg/injection) of bFGF on only the first and second days after the stroke. In contrast, the average score in this same test for all non-bFGF treated animals was approximately “5.”
[0081] bFGF also enhanced recovery (following MCA occlusion) when administered intravenously. As shown in FIGS. 8 A- 8 B, forelimb placing (FIG. 8A) and hindlimb placing (FIG. 8B) by animals given bFGF intravenously (see the closed circles) was equivalent to that of animals that were given bFGF intracisternally (at 0.5 μg/kg/injection for 4 weeks). The animals that served as controls for the intravenously injected group recovered to the same extent as the control animals for the intracisternally injected group (see the open circles on FIGS. 8 A- 8 B). Furthermore, the body weight of animals that were treated intravenously with bFGF were no different than the weight of animals given bFGF intracisternally.
[0082] Based on these results, both intracisternal and intravenous administration of bFGF, starting at least one day after ischemia, enhance behavioral recovery following focal cerebral infarction. Improved behavioral recovery in the rat model of ischemia used herein was seen without a change in infarct volume in bFGF-treated compared to vehicle-treated animals. The bFGF was given starting at one day after ischemia, beyond the apparent “therapeutic window” during which bFGF can reduce infarct size. The current findings represent the first demonstration that an exogenously administered neurotrophic growth factor can enhance behavioral recovery without a reduction in infarct size in an animal model of stroke.
[0083] Enhancement of recovery by bFGF was most pronounced on tests of sensorimotor function of the affected limbs and less pronounced on tests of reflex and postural function. Our infarcts did not completely damage forelimb and hindlimb cortical areas, which is compatible with recovery on limb placing tests following focal infarction in the MCA territory. Treatment with bFGF enhanced both the rate and degree of behavioral recovery during the first month after infarction.
GAP-43 Immunoreactivity is Selectively Increased in the Intact Sensorimotor Cortex Contralateral to Cerebral Infarcts Following bFGF Treatment
[0084] Possible mechanisms by which bFGF enhances recovery can include: (1) protection against retrograde cell death and/or (2) acceleration of new neuronal sprouting and synapse formation. It is possible that distant neurons in thalamus and elsewhere, spared by bFGF treatment, might establish new functional connections, thereby enhancing recovery. While not wishing to be bound to a particular underlying mechanism of action, examination of GAP-43 expression indicates that new growth of axonal processes, and possibly of dendritic processes, is likely to play an important role in functional recovery from ischemic injury.
[0085] At all time points examined (see above), the pattern of GAP-43 immunoreactivity in sham-operated animals receiving either bFGF or vehicle was similar to that described previously for the intact, mature rat brain (Benowitz et al., J. Neurosci. 8:339-352, 1988). Specifically, GAP-43 immunoreactivity was relatively high in the ventrolateral cerebral cortex and striatum, hypothalamus, parts of the thalamus, amygdala, and hippocampal formation. GAP-43 immunoreactivity was relatively low in the dorsolateral sensorimotor cortex, except for parts of FR 1,2, cortex in “anterior” brain sections and HL cortex in “posterior” sections.
[0086] Following stroke (induced by MCA occlusion), increased GAP-43 immunoreactivity was found in peri-infarct cortex in the ipsilateral hemisphere, peaking at three days after ischemia, consistent with previous reports (Stroemer, supra). There were no differences in GAP-43 immunoreactivity in the ipsilateral peri-infarct cortex between stroke/vehicle-treated and stroke/bFGF-treated animals. No differences were found in the contralateral hemisphere of stroke/vehicle-treated compared to sham/vehicle-treated or sham/bFGF-treated animals (FIGS. 9 A- 9 E and FIGS. 10 A- 10 E). However, in stroke/bFGF-treated animals, a selective increase in GAP-43 immunoreactivity was found within the contralateral sensorimotor cortex. Specifically, regions of high GAP-43 immunoreactivity were larger, spreading ventrally to involve the entire FR 1,2 cortex and part of FL cortex in “anterior” brain sections (FIGS. 9 A- 9 E), and to involve Parl cortex in “posterior” brain sections (FIGS. 10 A- 10 E).
Side Effects
[0087] Only treatment with the higher of two intracisternal doses of bFGF produced side effects. When the dosage was reduced from 3.0 μg/kg/injection to 1.5 μg/kg/injection, functional/behavioral recovery was enhanced but animals did not experience weight loss, and no animals died. Similarly, animals that received bFGF intravenously did not experience weight loss, and no animals died. It is unlikely that the improved behavioral scores we observed at the higher dosage were simply an artifact of lower body weight because all of the behavioral tests used, except the beam balance test, were done with the researcher supporting the animal. Of additional note is that, in spite of known mitogenic effects of bFGF on glial and endothelial cells, there was no gross evidence of abnormal cell proliferation in brains of bFGF-treated animals.
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The present invention relates to the treatment of central nervous system injuries by intracisternal or intravenous administration of polypeptide growth factors, such as basic fibroblast growth factor. This method provides significant benefits because administration can occur a substantial amount of time following an injury.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to an assembly for compression molding of articles made of plastics.
[0002] An assembly of this kind is normally composed of a main male plug and a complementary male plug, which are coaxial and are actuated toward each other in order to mold a dose of plastic material deposited on the complementary male plug so as to form an article.
[0003] When the step of deformation of the plastic material has ended, it is necessary to keep the main male plug and the complementary male plug pushed against each other, in order to allow the plastic material that has not yet hardened to maintain its shape until the process of stabilization of the plastic material has ended with the forming of a solid article.
[0004] In known molding assemblies, in order to keep the shape of the article the main male plug and the complementary male plug are pushed against each other with the same compression force that determined the deformation of the plastic material. This force, by persisting over time, can cause damaging mechanical stresses on the main male plugs and complementary male plugs. However, currently no solutions have been devised that allow to reduce the compression force to a value that allows to maintain the shape of the article until it stabilizes.
SUMMARY OF THE INVENTION
[0005] The technical aim of the present invention is now to obviate the above cited shortcomings of known molding assemblies by providing a solution that is technically simple and functionally valid.
[0006] Within the scope of this technical aim, an object of the present invention is to provide a molding assembly that is suitable to be installed in carousel apparatuses for the compression molding of articles made of plastic material, which comprise a plurality of molding assemblies.
[0007] This aim and this object are achieved with an assembly for the compression molding of articles made of plastic material, composed of a main male plug and a complementary male plug and characterized in that said complementary male plug is composed of: a stem, which is actuated by an actuation element and comprises a spindle that is guided in a tubular tang provided with a molding head that cooperates with said main male plug; a first spring, which is arranged on said spindle and acts between a collar of said spindle and said tubular tang; and a second spring, which is arranged on said spindle and is suitable to act, with a center bearing interposed, on said collar or on the end of said tubular tang that lies opposite said molding head, so as to determine: an inactive step of the complementary male plug, during which said first spring actuates said spindle into a stable position for resting against a shoulder of said tang, while said center bearing is spaced from said end of the tang and said second spring is locked between said stem and said collar; a compression step, during which both springs act on said tubular tang and said spindle does not rest against said shoulder, while said collar is spaced from said center bearing; and a reduced compression step, during which said first spring acts on said tubular tang and said second spring is locked between said stem and said collar, while said spindle does not rest against said shoulder and said center bearing is spaced from said end of said tang.
[0008] Another object of the invention is to provide a carousel that comprises a plurality of molding assemblies having the characteristics defined in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Further details of the invention will become better apparent from the following description of a preferred embodiment thereof, illustrated by way of non-limitative example in the accompanying drawings, wherein:
[0010] [0010]FIG. 1 is a sectional view of a carousel for molding articles, equipped with molding assemblies according to the invention;
[0011] [0011]FIG. 2 is an enlarged-scale sectional view of a molding assembly;
[0012] [0012]FIGS. 3, 4 and 5 are views of three successive operating conditions of the molding assembly.
[0013] [0013]FIG. 1 illustrates a carousel for molding articles made of plastic material, disclosed in copending patent application by the same Applicant, entitled “Apparatus for molding and applying liners in caps”, claiming Italian priority N o BO2001A000555, and to which reference is made here for better comprehension of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] The carousel is generally designated by the reference numeral 1 and is part of an apparatus for molding and applying liners made of plastic material in caps. The plastic material, by means of a dosage machine that is not shown, is deposited in doses on shuttles which, by way of transfer elements, are conveyed into the illustrated molding carousel 1 , where the doses are compressed on the shuttles so as to form disk-like liners that are designated by the reference letter G in FIG. 2. The liners are then conveyed onto another carousel, where they are removed from the shuttles and inserted in the caps.
[0015] As shown by FIG. 2, the shuttles are designated by the reference numeral 2 and are shaped like disks provided with an external slot 3 .
[0016] The molding carousel 1 comprises a cylindrical box 4 , which is rigidly coupled to the footing 5 and in which a vertical shaft 6 is supported rotatably; said shaft has an axis A and is turned by transmission elements, not shown in the drawings. The top end 7 of the shaft 6 is supported, by means of a bearing 8 , by a structure 9 that rises from the footing 5 . A drum 10 is keyed on the vertical shaft 6 and has an upper annular portion 11 and a lower annular portion 12 , between which there remains an annular recess 13 . The upper annular portion 11 has a plurality of cylindrical through seats 14 , whose axis B is parallel to the rotation axis A. The seats 14 are concentric to the axis A and angularly equidistant.
[0017] In the upper annular portion 11 there are multiple upper channels 15 and lower channels 16 , which run radially and connect the respective cylindrical seats 14 to a source of cooling fluid. A further plurality of cylindrical seats 17 is formed coaxially to the seats 14 , in the lower annular portion 12 .
[0018] The lower portion 12 has an annular cavity that divides it into two superimposed collars 18 and 19 , both of which are crossed by the seats 17 . In the upper collar 18 there is a respective additional cylindrical seat 20 (see also FIG. 2) that is radially internal with respect to each cylindrical seat 17 and is parallel to said seat.
[0019] In the lower collar 19 there are multiple vertical slits 21 , which are arranged radially and whose central planes contain the axes of the corresponding cylindrical seats 17 and 20 . An annular axial cam 22 rests under the drum 10 on the footing 5 , is concentric to the axis A, and comprises two vertically elongated concentric profiles. The cam 22 and the lower collar 19 are protected by a cylindrical jacket 23 , which has an upper edge 24 that skims the outer edge of the collar 19 .
[0020] Each one of the upper cylindrical seats 14 is closed in an upward region by an L-shaped body 25 and accommodates a main male plug, generally designated by the reference numeral 26 , which together with a respective complementary male plug 27 accommodated in the seats 17 forms one of the assemblies for molding the liners G. The main male plug 26 of each molding assembly is composed of a sleeve 28 , which is permanently inserted in the seat 14 and is closed in an upward region by a cylindrical head 29 that is slidingly and hermetically engaged in said sleeve and is provided with a diametrical hole 30 which is connected, through holes 31 of the sleeve 28 , to a respective channel 15 of the portion 11 of the drum 10 . The head 29 has a step for resting against a shoulder 32 of the sleeve 28 and a screw 33 is screwed into its top end; a screw 33 a having an axis B (see FIG. 1) and screwed through the L-shaped body 25 acts on said screw 33 . The upper end portion of the sleeve 28 has an outer step 33 b , on which there rests a ring made of rubber-like material 33 c , compressed between two metallic center bearings 33 d and 33 e and retained by an elastic ring 33 f . The ring 33 c rests against a shoulder 33 g of the seat 14 . In this manner, by acting on the screw 33 a it is possible to preload the ring 33 c against the shoulder 33 g and therefore the main male plug 26 . The head 29 has a tubular extension to which a cannula 34 is connected; said cannula forms a channel 35 that is connected to the diametrical hole 30 . The cannula 34 lies inside a tubular stem 36 , forming with it an interspace 37 , which is connected, by means of holes 38 of the tubular stem and of the sleeve, to a respective radial channel 16 . At the lower end, the tubular stem 36 is closed by a molding element that is constituted by a sort of cup 39 , which connects the interspace 37 to the channel 35 . The cup 39 , whose bottom constitutes the actual male plug, is accommodated in a bush 40 , whose inside diameter is greater than the outside diameter of the cup, so that an annular gap or interspace 41 is formed between them. The bush 40 is rigidly coupled to a ring 42 , which can slide on the stem 36 and in which there is a passage 43 that connects the gap 41 to a hose 44 for delivering compressed air. Each hose 44 is connected to a respective valve 44 a , which is actuated cyclically as the carousel turns by an abutment 44 b that is fixed to the structure 9 . The valve 44 a cyclically connects the hose 44 to a duct 44 c for feeding compressed air. The ring 42 , by means of a spring 45 that is interposed between said ring and the sleeve 28 , is actuated so as to rest against a shoulder 46 of the tubular stem 36 . Conveniently, the length of the bush 40 is such that in the position in which it rests against the shoulder 46 its lower edge protrudes below the cup 39 . Furthermore, the diameter of the bush 40 is smaller than the outside diameter of the shuttle 2 .
[0021] The complementary male plug 27 comprises a stem 47 crossed by a radial pivot 48 , which supports two free rollers 49 that engage, by rolling thereon, the pair of profiles of the cam 22 that is fixed to the footing 5 . A pin 50 is driven through the stem 47 and rotatably supports an additional upper pair of rollers 51 and 52 . Both rollers are arranged at the end of the pin that is external to the stem 47 relative to the axis B. The roller 51 engages the vertical slit 21 of the collar 19 , while the roller 52 can engage a sector that is fixed inside the cylindrical case 23 . The stem 47 contains a threaded bush 53 , into which the threaded end of a cylindrical spindle 54 is screwed; said spindle is mounted so that it can slide in a tubular tang 55 , to the top of which a screw 56 is screwed whose head has a larger diameter than the sliding hole of the spindle, so as to be able to abut against a shoulder 57 of the tubular tang 55 . A recess 58 is formed in said tubular tang and accommodates a ring 59 , which is monolithic with the spindle 54 , and a spring 60 , which acts between the tang 55 and the ring 59 , with a spacer ring 61 interposed, so as to actuate the head of the screw 56 into abutment against the shoulder 57 . An additional spring 62 is accommodated in a recess 63 of the stem 47 that surrounds the bush 53 so as to act, with a center bearing 64 interposed, against the lower edge of the tang 55 and act as a resting element for the ring 59 . The spring 62 rests on the bottom of the recess 63 with a spacer ring 64 a . The rings 61 and 64 a allow to adjust the preloading of the springs 60 and 62 . A seat is provided at the top end of the tubular tang 55 , and a shuttle holder insert 65 is screwed therein; said insert has a central pivot 66 , which is suitable to engage in the central hole of the shuttle 2 so as to constitute, together with said shuttle, a molding head. An interspace 67 remains between the insert 65 and the head of the screw 56 and allows the spindle 54 to perform a short stroke with respect to the tang 55 in contrast with the return action applied by the spring 60 . When the head of the screw 56 rests on the shoulder 57 , an interspace 67 a that is not as high as the interspace 67 is formed between the center bearing 64 and the lower edge of the tubular tang 55 .
[0022] A bush 68 is fixed in each one of the cylindrical seats 20 , and a rod 69 can slide therein; the pin 50 is inserted in a downward region in said rod. The rod 69 has an upper portion that has a reduced diameter and forms inside the bush 68 an abutment 69 a , which protrudes out of the bush 68 . A block 70 is fixed slidingly on said portion, and two superimposed forks 71 and 72 protrude from said block; the prongs of said forks form two semicircular curves: the upper one is suitable to receive the bush 40 and the lower one is suitable to receive the slot 3 of the shuttle 2 . The numeral 73 designates a spring that is interposed between the block 70 and a nut 73 a that is screwed onto the end of the rod 69 . The purpose of the spring 73 is to actuate the block 70 downward in order to keep it rested against the abutment 69 a when the rod 69 is actuated upward by the cam 22 together with the stem 47 . A washer 73 b is arranged on the rod 69 , and a spring 74 rests therein in abutment against the lower edge of the bush 68 that guides the rod 69 .
[0023] The operation of the described carousel is as follows.
[0024] The shuttles 2 , already provided with a dose of plastic material preformed in the dosage machine, are transferred by an appropriate transfer element onto the molding carousel 1 , where they are accommodated in the recesses formed between the prongs of the lower forks 72 that engage in the slot 3 of said shuttles.
[0025] The shuttles 2 are then locked by the subsequent upward stroke of the complementary male plugs 27 , which are actuated by the cam 22 that causes the engagement of the pins 66 in the holes of the shuttles 2 so that they cannot escape from the seats between the prongs 72 of the block 70 .
[0026] As the upward stroke of the complementary male plugs continues, the shuttles 2 make contact with the lower edge of the bushes 40 and therefore actual molding begins, compressing the doses of plastic material previously deposited on the shuttles 2 against the bottoms of the cups 39 so as to form circular liners G.
[0027] The molding performed by each assembly composed of a main male plug 24 and a complementary male plug 27 occurs according to the following sequence.
[0028] In the initial position (shown in FIGS. 2 and 3), i.e., when the resistance to compression offered by the dose is not yet significant, the screw 56 abuts against the abutment 57 and the spring 62 is locked, in the preloaded condition, between the bottom of the recess 63 and the collar 59 of the spindle 54 . The interspace 67 a between the center bearing 64 and the edge of the tang 55 , owing to the preloading of the spring 60 , remains unchanged.
[0029] As the resistance offered by the plastic material increases as the stem 47 and the spindle 54 rigidly coupled thereto rise, the spindle 54 moves with respect to the tang 55 , so that the center bearing 64 stops against the lower edge of the tang 55 , allowing the collar 59 to move away from it.
[0030] At this point one has the situation of FIG. 4, in which the maximum compression thrust applied by the cam 22 is transmitted to the tang 55 and therefore to the shuttles 2 by means of the two springs 60 and 62 , which are arranged in parallel.
[0031] The doses of plastic material are sized so as to widen due to compression until they occupy the entire chamber comprised between the shuttle 2 and the bottom of the cup 39 and is surrounded peripherally by the bush 40 . Once the liners G have been molded, the cam 22 allows the spindles 54 to descend, so as to allow the collar 59 to abut against the center bearing 64 and therefore, by descending further, to entrain it under the edge of the tang 55 , so as to render ineffective the lower spring 62 , which is locked once again between the collar 59 and the stem 47 (see FIG. 5). When the center bearing 64 descends below the edge of the tang 55 , the compression with which the complementary male plug 27 acts on the liner, which is molded by then, is applied only by the upper spring 60 and is maintained by it by way of the cam 22 for a rotation angle of the carousel 1 that is sufficient to ensure that the shape of the liners is maintained until it has stabilized.
[0032] Once the molding step has ended with the spacing of the complementary male plug 27 from the main male plug 26 , the shuttles that support the already-formed liners G are then transferred onto an insertion carousel, where the liners G are separated from the shuttles 2 along a first arc of rotation and the liners are inserted in caps along a subsequent arc.
[0033] It is evident that the assemblies according to the invention perfectly achieve the intended aim and objects. In particular, it is possible to reduce the compression force after molding the liners to a value that maintains the shape of the liners until it has stabilized yet reduces the mechanical stresses on the main male plugs and complementary male plugs.
[0034] The invention can of course be applied also in carousels that do not have shuttles and in which the molding heads are integrated in the inserts 65 so that the plastic material is compressed between the cup-like element 39 and the upper face of the insert 65 .
[0035] The disclosures in Italian Patent Application No. BO2001A000557 from which this application claims priority are incorporated herein by reference.
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An assembly for the compression molding of articles made of plastic material, composed of a main male plug and a complementary male plug which comprise a stem, actuated by an actuation element with a spindle guided in a tubular tang provided with a molding head cooperating with the main male plug; a first spring, arranged on the spindle acting between a collar of the spindle and the tubular tang; a second spring, arranged on the spindle acting on the collar or on the end of the tang that lies opposite the molding head, to determine an inactive molding step of the complementary male plug, a compression step, and a reduced compression step.
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BACKGROUND OF THE INVENTION
The present invention relates to a monitor circuit for use in anti-skid brake control systems and the like and, more particularly, to such a monitor circuit that energizes an indicator when powered-up or when a fault has been detected in the system. Moreover, the invention is directed to such a monitor circuit that has relatively improved reliability.
Anti-skid brake control systems with which the monitor circuit of the present invention may be used are disclosed, for example, in U.S. Pat. No. 3,917,359 and in copending U.S. Patent Applications Ser. No. 685,267, filed May 11, 1976, for "Anti-Skid Brake Control System with Short Circuit Protection" now U.S. Pat. No. 4,040,676, issued Aug. 9, 1977; Ser. No. 769,255, filed Feb. 16, 1977, for "Anti-Skid Brake Control System with Power-Up Delay"; Ser. No. 770,535 filed Feb. 22, 1977, for "Anti-Skid Brake Control System with Circuit For Monitoring Slower Wheel"; and Ser. No. 779,205, filed Mar. 18, 1977, for "Capacitive Shunt to Minimize Noise Effects in an Anti-Skid Brake Control System". These copending applications are assigned to the same assignee as the present application.
The principal purpose of an anti-skid brake control system is to provide automatic overriding control of the brakes of a vehicle when an incipient or actual skid (hereinafter skid), a locked wheel, or a like condition exists. Upon detecting such a condition, the system dumps, for example, to the ambient environment, part or all (hereinafter a percentage) of the brake operating fluid pressure (hereinafter air pressure) which the vehicle operator then may be attempting to apply manually by pressing on the vehicle brake pedal with his foot. By dumping a percentage of the air pressure the skidding wheels, for example, are permitted to re-gain traction with the road surface. After the skid, locked wheel, or like condition has terminated, the system stops the air pressure dump allowing all of the air pressure requested by the driver to be delivered to the respective air brakes.
In such a system a transducer produces an AC transducer signal that has a frequency indicative of the speed of the vehicle wheel being monitored. A controller is operative in response to the AC transducer signal to produce a dump signal that energizes one or more solenoids in a modulator air brake valve to dump a percentage of the air pressure requested by the driver when the condition or change of the AC transducer signal indicates a skid or locked condition of the wheel. A safe direction failure control circuit monitors various portions of the system and is operative to shut down the system upon detecting a fault. Moreover, a monitor circuit coupled to the safe direction failure control circuit watches the output of the latter and is operative in response to detection of a fault thereby to energize an indicator lamp warning the driver that a fault has been detected in the system and, usually, that the system has been shut down or made inoperative so that full manual control of the vehicle brakes has been restored.
In a vehicle that has a plurality of axles, such as a truck, there may be a separate anti-skid brake control system associated with each respective axle. For example, in a vehicle with two axles respective transducers would be coupled to each of the forward wheels and would deliver AC transducer signals to a common controller which is operative to dump a percentage of the air pressure requested by the driver to be delivered to the brakes of the forward wheels if either of those wheels skids or locks. Respective transducers and a further common controller would be similarly associated with the rear wheels and air brake valves thereof.
A common monitor circuit may be coupled to the respective safe direction failure control circuits of all the controllers or to a common safe direction failure control circuit for plural controllers to provide at least two useful functions. The first or checking function of the monitor circuit is to energize a warning lamp, for example, positioned on the dashboard, each time the system or systems and/or the monitor circuit itself are powered up, i.e. electrical power is supplied thereto, to indicate to the driver that the lamp and the other parts of the system or systems are operable; and the second or warning function is to watch the indicator output signals from the safe direction failure control circuit or circuits to energize the warning lamp whenever a fault is detected to indicate the same to the driver. The latter type energization of the warning lamp may be employed to indicate that manual control of the vehicle brake system or at least one portion thereof, e.g. the one associated with the wheels on one axle, has been returned to the driver.
Intermittent energization of the warning light by the monitor circuit has been found to occur on some vehicles which have the other parts of the anti-skid brake control system functioning properly. It has been determined that transient electrical signals (transients), which commonly occur in most vehicles, particularly in electronic systems thereof, have been the cause of such intermittent energization that provides undesirably false information to the driver. Moreover, since the warning lamp coupled to the indicator output terminals of the monitor circuit must be easily removed for replacement purposes, there is a possibility that a short circuit may occur thereat when the warning lamp is removed and/or replaced; and it has been found in the past that a power surge upon short circuiting may cause damage to one or more of the electrical components of the monitor circuit.
SUMMARY OF THE INVENTION
By the present invention the reliability of a monitor circuit for anti-skid brake control systems or the like is improved by immunizing the same from the influence of transients and short circuits across the indicator output terminals.
In one embodiment the checking function is achieved, as in the past, by a resistor and capacitor timing circuit coupled in the monitor circuit to effect energization of the warning lamp from the time the monitor circuit is sufficiently energized until the capacitor in the timing circuit has charged to a predetermined level, and the warning function is effected by discharging the capacitor. However, in accordance with the present invention the rate at which such discharging is effected is sufficiently reduced so that relatively short-lived transients will not cause sufficient discharging to effect energization of the warning lamp to provide its warning function. In a preferred embodiment the delay mechanism is a resistor of sufficient size to preclude energization of the warning lamp when expected transients occur but, on the other hand, sufficiently small to assure relatively prompt discharge of the capacitor to turn on the warning lamp after a fault has been detected. Additionally, a current limiting impedance is provided in series with the indicator output terminals to reduce the power surge, either current or voltage, if such terminals become short circuited preferably without appreciably affecting the intensity of the illumination produced by the warning lamp. That impedance may be a current limiting resistor, and in an alternate embodiment may be a self-heating resistor that increases its resistance with respect to increased temperature with this latter form being preferred when short circuits of relatively long duration are expected.
With the foregoing in mind it is a primary object of the invention to provide a monitor circuit of the type described that is improved in the noted respects.
Another object is to improve the reliability of a monitor circuit and particularly such a monitor circuit used in connection with an anti-skid brake control system or the like.
An additional object is to reduce and/or to eliminate damage to circuit components in a monitor circuit in the event of a short circuit at the output terminals thereof.
A further object is to reduce and/or to eliminate false operation of a monitor circuit due to electrical noise transients or the like.
These and other objects and advantages of the present invention will become more apparent as the following description proceeds.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described in the specification and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail a certain illustrative embodiment of the invention, this being indicative, however, of but one of the various ways in which the principles of the invention may be employed.
BRIEF DESCRIPTION OF THE DRAWING
In the annexed drawing:
The sole FIGURE is a schematic electric circuit diagram, partly in block form, illustrating a monitor circuit in accordance with the invention coupled in an anti-skid brake control system of a vehicle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now more particularly to the drawing, a monitor circuit in accordance with the invention is generally indicated at 1 coupled in an anti-skid brake control system 2, which ordinarily is operative upon sensing a skid, locked wheel, or the like to effect overriding control of the air brake system 3 of a vehicle. As will be described further below, the monitor circuit 1 is operative to energize a warning lamp 4 whenever electrical power is initially supplied to the monitor circuit and to the remainder of the anti-skid brake control system 2, for example, by the vehicle battery 5 or other source of electrical power. The monitor circuit 1 also is operative to energize the warning lamp 4 when a fault has been detected in the anti-skid brake control system 2.
In describing the monitor circuit 1 in accordance with the invention as used in connection with an anti-skid brake control system 2, it will be assumed, for example, that the system is coupled for overriding manual control of the conventional air brake system 3 of a truck vehicle, although it will be appreciated that the monitor circuit 1 and the system 2 may be similarly employed in other vehicles.
In the air brake system 3 a primary supply of air pressure is provided from the vehicle air supply 10 via a fluid connection 11 to a conventional air brake valve 12 and via a fluid connection 13 to the brake pedal assembly 14. The driver may manually operate the brake pedal by his foot, for example, to determine the amount of control air pressure supplied via fluid line 15 to the air brake valve 12 to open the latter a corresponding amount, thereby to provide a controlled amount of brake operating primary air pressure delivered via the fluid line 16 to the vehicle air brakes 17 to operate the same to slow the vehicle in conventional manner.
The air brake valve 12 includes a modulator valve portion, not shown, that may be solenoid operated in conventional manner to dump a percentage of the air pressure being called for by the driver in response to a dump signal delivered on the electrical output 17 of the system 2. The dump signal energizes one or more solenoids in the air brake valve 12, for example depending on the magnitude of the dump signal, to dump a percentage of the air pressure, thereby allowing the skidding or locked wheels to regain traction with the road. Various types of modulator valve portions for air brake valves are found in the prior art patent literature, for example, and one particular type of valve with which the system 2 may be used is specifically disclosed in a brochure entitled "Triple Action Skid Control", published by B. F. Goodrich Co., March, 1975.
The anti-skid brake control system 2 may include a conventional transducer 20 mounted in one of the wheel assemblies of the vehicle, not shown, to produce an AC transducer signal having a frequency indicative of the wheel speed. The transducer 20 may include a permanent magnet mounted to rotate with the wheel being monitored and a coil fixedly mounted relative to the rotatable magnet and in which the AC transducer signal is induced in response to such rotation.
The system 2 also includes a controller 21, which is operative in response to the frequency of the AC transducer signal and/or changes in the same to produce the dump signal on line 17 when a skid, locked wheel, or the like is detected. In the controller 21 a frequency to voltage converter 22, which may be a conventional device including squaring and integrating circuits, for example, converts the AC transducer signal to a DC voltage on line 23 with the amplitude of such DC voltage being representative of the frequency of the AC transducer signal and, thus, of the wheel speed. A deceleration detector 24, which may be a conventional differentiating circuit, monitors downward changes in the DC voltage on line 23 as an indication of wheel deceleration and produces a deceleration signal on line 25 indicative of the wheel deceleration. If the rate of downward change of the DC voltage on line 23, as reflected by the magnitude of the deceleration signal on line 25, exceeds a predetermined excessive level, a dump pressure control circuit 26, which may be a comparator amplifier or the like, responds to the same to produce the dump signal, for example at a magnitude or of a character representative of the magnitude of the deceleration, on the system output 17 to dump a percentage of the air pressure. The production of such an excessive deceleration signal ordinarily would be indicative of an incipient or actual skid, therefore, by dumping a percentage of the air pressure requested by the driver to slow the vehicle, which has begun to skid, the skidding wheel is permitted to spin up at least slightly to regain at least some of its traction with the road surface.
The DC voltage on line 23 also is monitored by a wheel lock detector 27, which responds, for example, to a substantially instantaneous drop of the DC voltage by more than a predetermined amount as an indication that the wheel is going into a locked condition. Such detection ordinarily would occur after excessive deceleration had been detected. Moreover, upon detecting such locked wheel condition, the wheel lock detector 27 produces a wheel locked signal on line 28 to energize the dump pressure control 26 to produce a dump signal, which, as above, tends to alleviate the locked wheel condition.
A safe direction failure control circuit 30 monitors the transducer 20 via a sensor open detector 31 and may similarly monitor the operability of other parts of the system 2. The sensor open detector 31 may be a transistor switching circuit that monitors the completeness of the electrical circuit in which the coil, for example, of the transducer 20 is connected. If the sensor open detector 31 detects an open circuit at the transducer, a signal indicating the same is produced on line 32 for delivery to the safe direction failure control 30. Accordingly, such open circuit fault at the transducer 20 detected by the sensor open detector 31 will trigger the safe direction failure control 30 to disable the dump pressure control 26, for example by cutting off power supplied to the latter via line 33, so that the system cannot override manual operation of the air brake system 3. Moreover, the safe direction failure control 30 preferably is a self-latching type circuit that maintains the dump pressure control 26 disabled until the fault detected in the system 2 has been corrected and the system has been deenergized and subsequently re-energized.
The safe direction failure control 30 also is connected by line 34 to the monitor circuit 1 for operating the same to energize the warning lamp 4 whenever a fault has been detected in the system 2 and the system has been disabled or shut down.
The foregoing description of the transducer 20, controller 21, and air brake system 3 is provided to exemplify one type of anti-skid brake control system arrangement with which the monitor circuit 1 in accordance with the invention may be employed, and more detailed descriptions of these components are presented in the above-mentioned patent and copending applications, which to the extent they may be considered necessary to complete the present disclosure are hereby incorporated by reference. Moreover, although the controller 21 is illustrated and described as being operative to produce a dump signal in response to an AC transducer signal from a single transducer 20 that monitors one vehicle wheel, it will be appreciated that plural transducers may be employed to monitor plural respective wheels producing respective AC transducer signals indicative of the respective wheel speeds, and the controller 21 may be appropriately modified in accordance with the above-referenced disclosures to respond to the respective AC transducer signals. In a preferred anti-skid brake control system a pair of transducers are employed to monitor the rotational speed of a pair of wheels on the opposite sides of a common axle of the vehicle, as is described, for example, in the copending application entitled "Anti-Skid Brake Control System with Circuit for Monitoring Slower Wheel"; however, it will be appreciated that the transducers and/or controller may be employed to monitor the adjacent tandem wheels of a vehicle, for example, as in U.S. Pat. No. 3,847,446. As desired, the controller 21 may be responsive to only a single transducer 20 to dump air pressure from a single air brake valve 12, may be responsive to several transducers 20 to produce a dump signal to operate several air brake valves 12, may be responsive to all of the transducers 20 of the vehicle to produce a dump signal to operate all of the air brake valves 12 associated with the vehicle, etc.
Electrical power is provided to the various portions of the anti-skid brake control system 2 from the vehicle battery 5 via a pair of switches 35, 36, which may be operated jointly or independently, and a voltage regulator 37, for example, that delivers regulated V cc voltage from an output terminal 38 to correspondingly labeled input terminals of the several controller parts, such as terminal 38a, and an unregulated power signal at terminal 39, which may be controllably delivered by the safe direction failure control 30 on line 33 to the dump pressure control 26, as described above, and from the latter as the dump signal on line 17 to operate the solenoids in the air brake valve 12. The negative side of the battery 5 is coupled to the chassis of the vehicle to provide a chassis ground reference potential 40 for the monitor circuit 1 and the other portions of the anti-skid brake control system 2 including the voltage regulator 37, and the voltage regulator 37 also includes a connection 41 as a relative circuit ground reference potential that may be the same or different from the chassis ground 40, as desired. The electrical power supplied to the monitor circuit 1, as indicated, from the vehicle battery 5 and switch 35, which may be closed in response to closure of the vehicle ignition switch also passes a conventional bridge rectifier 42 for polarity correction purposes.
In the monitor circuit 1 an output circuit 43 includes a comparator amplifier 44, such as an integrated circuit No. NE555V with several connections thereto as exemplified in the drawing, a transistor switch 45, and an indicator output 46 having a pair of terminals 47, 48 across which the warning lamp 4 or other indicator is connected. Ordinarily the comparator amplifier 44 maintains the transistor switch 45 nonconductive so that the warning lamp 4 remains de-energized; however, the output circuit 43 is operative in response to a voltage of at least a predetermined amplitude being provided to the input 49 of the comparator amplifier 44 causing the latter to bias the transistor 45 to conduction thereby completing a circuit to energize the warning lamp 4.
In accordance with one aspect of the invention a resistor 50 is connected in series circuit with respect to the indicator output 46 and the transistor 45. It is the purpose of the resistor 50 to limit the size of the power surge that may occur if the terminals 47, 48 were short circuited, for example during removal and/or replacement of the warning lamp 4 in its socket on the vehicle dashboard. The size of the resistor 50 should be sufficiently small to avoid appreciable reduction in the intensity of the light output from the warning lamp 4 and at the same time should be sufficiently large to limit the instantaneous voltage and/or current to the transistor 45 and/or drawn from the bridge rectifier 42 upon occurrence of such short circuit to avoid damage to those elements. The shorter the duration of any expected short circuit, the smaller may be the resistor 50. The size of the resistor 50 may be, for example, 10 ohms when the battery voltage is on the order from about 12 to about 18 volts and the transistor 45 may be an A5T4028. However, if desired, the resistor 50 may be a self-heating type resistor that increases its resistance with increasing temperature to limit the voltage and/or current from the bridge rectifier 42 and to the transistor 45 satisfactorily if a lengthy short circuit occurred at the indicator output 46; of course, the operative current and/or voltage parameters of such a self-heating resistor preferably would be selected to avoid self-heating when the warning lamp 4 is properly connected across the indicator output 46.
To limit and/or to provide some degree of regulation in the voltage applied across the comparator amplifier 44, a resistor 51 isolates the same from the bridge rectifier 42, and a transistor 52, which is coupled in the manner illustrated to provide a voltage regulating function similar to that of a conventional zener diode, is connected across the comparator amplifier.
The monitor circuit 1 also includes a timer circuit 53, having a series connected capacitor 54 and resistor 55 coupled across the transistor 52, as shown, with the node juncture 56 between the capacitor and resistor also being coupled to the input line 49 of the comparator amplifier 44. It is the purpose of the timer circuit 53 to operate the output circuit 43 for a predetermined duration each time the switch 35 is closed to power up the monitor circuit 1, whereupon the warning lamp 4 is energized to indicate its operability to the driver. Accordingly, when the switch 35 is closed, voltage is supplied to the timer circuit 53, whereupon the capacitor 54 charges at a rate determined by the RC time constant of the circuit in which it is connected. Initially the voltage at the juncture 56 is approximately equal to that provided to the monitor circuit 1 by the bridge rectifier 42 less the voltage drop across the resistor 51, with the amplitude of such nodal voltage being sufficient to operate the output circuit 43 to energize the warning lamp 4. Moreover, the output circuit 43 will continue to energize the warning lamp 4 as the capacitor 54 charges until the amplitude of the nodal voltage drops below the predetermined level necessary to operate the comparator amplifier 44, whereupon the transistor 45 is cut off to de-energize the warning lamp 4.
An input circuit 60 coupled to the line 34, for example, includes a transistor switch mechanism 61 for effectively bypassing the timer circuit 53 by discharging the capacitor 54 to raise the amplitude of the voltage at the node 56 to a sufficient level to operate the output circuit 43 to energize the warning lamp 4 when the safe direction failure control 30 detects a fault in the system 2 and produces a fault signal on line 34. Such energization of the warning lamp 4 accordingly indicates to the driver that a fault has been detected in the system 2 and usually a part or all of such system has been disabled.
The input circuit 60 also includes a pair of resistors 62, 63, which ordinarily provide a bias voltage to the transistor 61 to maintain the same cut off. Moreover, the input circuit includes a NAND gate 64, as shown with three individual input terminals 65, 66, 67 that are connected to respective lines 34 from respective safe direction failure control circuits 30 of respective controllers 21, only one of which is illustrated. The three portions of NAND gate 64 include respective diodes 68, 69, 70 and respective resistors 71, 72, 73.
In operation of the monitor circuit 1 after the capacitor 54 of the timer circuit 53 has sufficiently charged so that the warning lamp 4 is de-energized, assuming that the system 2 is properly operating, a high or relatively positive voltage signal will be produced by the safe direction failure control 30 on the line 34 to reverse bias the diode 68 in the NAND gate 64, thereby assuring that a sufficiently positive voltage is applied to the base of the transistor 61 to bias the same in its cut off condition. However, when a fault is detected by the safe direction failure control 30, it produces a relatively low voltage fault signal, such as zero volts, on line 34, whereupon the diode 68 in the NAND gate 64 becomes forward biased and the transistor 61 becomes conductive effectively to bypass the timer circuit 53 by discharging the capacitor 54, thereby raising the amplitude of the nodal voltage at the node 56 whereupon the output circuit 43 energizes the warning lamp 4. The input terminal 66, 67 may be coupled as the terminal 65 to respective safe direction failure control circuits of other controllers, for example, in the overall anti-skid brake control system arrangement of the vehicle to enable energization of the warning lamp 4 when other fault signals are received at such terminals.
In the past the transistor 61 has been coupled directly across the capacitor 54 to assure prompt energization of the warning lamp 4 when a fault signal was received on line 34 from the safe direction failure control 30. However, transients on the line 34, for example, or elsewhere in the monitor circuit 1 had been found to trigger the transistor 61 causing immediate discharge of the capacitor 54 and turn on of the warning lamp 4 with the latter remaining energized after the termination of the transient and cut off of the transistor 61 until the timer circuit 53 had reset itself by a re-charging of the capacitor 54 to reduce the amplitude of the nodal voltage below the level sufficient to operate the output circuit 43.
Therefore, in accordance with anoher aspect of the invention an impedance preferably in the form of a resistor 74 has been added in series circuit with the emitter collector discharge path of the transistor 61 to slow the rate at which the capacitor 54 discharges, i.e. to increase the discharge time, when the transistor 61 is turned on. The size of the resistor 74 should be sufficiently large to prevent raising of the amplitude of the nodal voltage to a level sufficient to operate the output circuit 43 to turn on the warning lamp 4 in response to ordinarily expected transients, but the resistor should be sufficiently small to assure that the warning lamp 4 will be energized within a relatively short time after the detection of a fault by the safe direction failure control 30. In an exemplary monitor circuit 1 the values for the capacitor 54, resistor 55, and resistor 74 were 15 uf., 330K ohms, and 5.1K ohms, respectively. These values were found satisfactory to assure that the test function of the monitor circuit 1 would be operative to provide a reasonably lengthy energization of the warning lamp 4 upon power-up and to avoid turn on of the warning lamp in response to the ordinarily expected transients.
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A monitor circuit coupled to an anti-skid brake control system or the like has as one function the energization of a warning lamp each time the system is powered-up and as a second function the energization of that lamp when a fault is detected in the system. The invention relates to improvements in such a monitor circuit, including a delay mechanism to preclude inadvertent energization of the warning lamp in response to electrical noise signals, for example, that are common in a vehicle, and a protective mechanism to prevent destruction of parts of the monitor circuit if the output terminals thereof coupled to the warning lamp are short circuited.
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CROSS-REFERENCE TO RELATED APPLICATION
This application s a continuation-in-part of U.S. patent application Ser. No. 07/536,873, filed Jun. 12, 1990, now U.S. Pat. No. 5,160,188.
BACKGROUND OF THE INVENTION
1. Field Of The Invention
The present invention relates generally to modular office furniture. The present invention specifically relates to support stanchions for modular, free standing open-plan office furniture having unitary internal power routing facilities, and provision for selective mounting of plural electric and electronic accessories.
2. State Of The Prior Art
In the modern office environment, ready accessibility to electrical power is highly desirable. In today's office, common furniture such as desks and other work surfaces must coexist with a variety of electric and electronic equipment such as telephones, clocks, computers, adding machines, and many other types of devices. However, since office furniture is generally chosen and installed long after basic electrical service is installed in a typical office or office building, providing electrical service close to or mounted in a desk or work surface is difficult. Typically, office workers must use extension cords, multiple-outlet junction boxes, and other cumbersome and potentially dangerous means to route electrical power to a convenient location near the desk surface.
Prior inventors have attempted to combine electrical power service with furniture in various ways. For example, U.S. Pat. No. 3,862,785 (Scheerhorn, et al) discloses a secretarial work station including a work surface, end walls, a shelf and a partitioned upper portion which may receive a telephonic unit in one end. However, the work station of Scheerhorn, et al does not provide standard 120 VAC electrical service outlets for connection to different articles.
Another means for supplying power to particular places in an open-plan office is to use a floor-to-ceiling service pole such as that disclosed in U.S. Pat. No. 4,284,840 (Baker). The Baker patent provides plural outlets mounted in an elongated pole which extends from the floor to the ceiling. Electrical wiring is routed into the pole and connects to outlets. However, use of a service pole requires placing an obstacle in the office, which may affect furniture placement, and also requires running an extension cord to a desk, work surface, or other devices desired to be attached to the electrical service.
Still other inventors have attempted to integrate electrical service and office furniture by building the electrical facilities into the work surface. For example, U.S. Pat. No. 4,792,881 (Wilson et al) discloses a work surface with a power and communication module set into the rear portion of a work surface. The module includes plural outlets set into a power strip, and communications facilities provided in a module. The entire apparatus is located in a recess below the work surface and is accessible by lifting a hinged panel. However, the placement of the power module in the rear lateral portion of the work surface effectively precludes use of that area of the work surface for office work. Since access to space by lifting panel may be required at any time to connect or disconnect electrical cables to the outlets, an office worker would have to move any objects placed on panel to access space. Further, the Wilson et al disclosure requires complex manufacturing processes to produce a desk top having the proper cutout space to accommodate the power and communication module.
Another approach is to mount utility service in a wall immediately adjacent to the work surface, as disclosed in U.S. Pat. No. 4,603,229 (Menchetti) which shows an office environment having a suspended ceiling, wall panels, and a false wall panel behind which are located a telephone outlet module and an electrical service receptacle. Electrical power is routed to the sides of the modules by wiring placed behind the false wall panel in the cavity of the wall structure. However, using the arrangement disclosed by Menchetti requires that the vertical wall surface be located immediately adjacent to the work surface or desk, an arrangement which may be undesirable to some office workers and office furniture designers.
Finally, attempts have been made to facilitate wiring near or within a desk surface by providing a wiring support located immediately below the work surface, as disclosed in U.S. Pat. No. 3,114,584 (Wilmer). However, the wiring support of Wilmer does not fully enclose the wires or cables, but merely supports them on an elongated terminal block using brackets installed beneath the desk. This arrangement is undesirable in some office environments, since exposed wiring may be jostled, disturbed, or even severed.
Thus, there is a need for an apparatus for supporting and locating electrical service outlets immediately adjacent to and conveniently located near an ergometric work surface or desk top. The present invention is directed toward fitting that need.
SUMMARY OF THE INVENTION
The present invention comprises a fully enclosed structural support stanchion for modular furniture having an internal cavity which may receive standard modular office furniture electrical service cabling, and which is provided with a demountable front accessory panel to which plural electrical or electronic accessories may be mounted, such that a portion of the accessory extends into the stanchion and can releasably connect either to one end of the standard modular furniture electrical service cabling or to the building electrical system.
The stanchion is constructed with rigid materials so that it can act as a support for an overhead bookshelf or other storage facility, and the stanchion is further provided with a large internal storage cavity into which small office supplies or other articles may be placed and stored behind a hinged, selectively closable door. The stanchion further includes an elongated bracket support which may receive standard shelf brackets, permitting the stanchion to act as a cantilever support for structures such as a shelf secured to the shelf brackets.
The stanchion is preferably constructed in a right triangular vertical columnar configuration including a rigid frame having vertically elongated rigid frame panels secured at a right angle, top and bottom plates each resembling a right isosceles triangle. A front-facing opening is provided in the base plate to enable the plate to clear and receive an electrical cabling system. The entire interior of the stanchion is hollow, enabling the interior to receive both the electrical cabling system and demountable accessories which are joined to the cabling system using a novel mounting bracket.
The electrical cabling system comprises a conventional cable and a modular connector shell secured to a rigid back plate and a mounting bracket which receives a modular electrical receptacle. The mounting bracket enables the modular, demountable receptacle to be simultaneously mechanically mounted on the bracket and electrically connected to the cable connector shell. The mounting bracket and the base plate of the stanchion are provided with axially aligned holes to receive conventional fasteners such as bolts for securing the mounting bracket, and the base plate, to the base unit or desk.
The stanchion frame members define a right isosceles triangular cavity within the interior of the stanchion. The frame members further include outward-facing substantially "C" shaped columns secured to their free ends. The "C"-shaped columns are provided with outward-facing narrow, elongated faces which provide securement means for plural front facia panels. Preferably, three facia panels are used: a top panel, middle panel, and bottom panel. The middle and bottom panels are demountable, and may be fitted with various accessories depending upon the desires of the office worker. For example, the middle panels may be used in conjunction with a telephone, clock, fan, air purifier, pencil holder, tablet holder, and similar accessories; and the bottom panels may be used in conjunction with electrical receptacles, telephone power receptacles, and similar accessories.
The stanchions include an elongated, vertical bracket to which plural accessories may be secured in cantilever fashion. For example, a conventional shelf or like device may be secured to a pair of spaced-apart stanchions such that the shelf joins the stanchions which act as opposing supports for the shelf.
Accordingly, it is a primary object of the present invention is to provide a compact, aesthetically pleasing, unitary support stanchion and electrical service module which provides structural support for modular office furniture components and also permits selective connection of plural electrical or electronic accessories either to the stanchion electrical service outlets or to the building electrical system.
A further object of the present invention is to provide unitary modular furniture support stanchions having fully-enclosed electrical service cables and outlets which permit placement of the modular furniture in any desired position within an office environment.
Still a further object of the present invention is to provide an electrical service outlet mountable within a modular furniture structural support stanchion which may be rapidly and easily connected or disconnected to standard modular furniture electrical service cables.
Yet another object of the present invention is to provide a plurality of electrical and electronic accessories which may be quickly and easily mounted and demounted from a modular furniture support stanchion and from the internal cable or wiring harness mounted within the stanchion.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing invention, as described and claimed fully below, may be constructed in plural embodiments of which one preferred embodiment is shown in the accompanying drawings of which:
FIG. 1 is a front perspective view of a desk and work surface incorporating two corner support stanchions according to the present invention and an overhead storage compartment mounted on the stanchions.
FIG. 2 is a front elevation view of one of the stanchions of FIG. 1.
FIG. 3 is a bottom plan view of the stanchion of FIG. 1.
FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 3.
FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 2.
FIG. 6 is a front perspective view of the bottom interior portion of the stanchion of FIG. 1 additionally showing the internal mounting structure of modular furniture to which the stanchion may be secured.
FIG. 7 is a front elevation view of the interior bottom portion of a stanchion of FIGS. 1 through 6, additionally showing part of a standard modular furniture cable connector used to supply power to the stanchion power outlets.
FIG. 8 is a side elevation view of the structure of FIG. 7.
FIG. 9 is a top plan view of the structure of FIGS. 7 and 8.
FIG. 10 is an exploded perspective view of the structures of FIGS. 7 and 8, shown with a mating modular electrical receptacle.
FIG. 11 is a perspective view of the structures of FIG. 10, assembled.
FIG. 12 is a cross-sectional view taken along line 12--12 of FIG. 10.
FIG. 13 is a top plan view of the shelf shown in FIG. 1.
FIG. 14 is a cross-sectional view taken along line 14--14 of FIG. 13.
FIG. 15 is a front view of a stanchion of the present invention showing an air purifier accessory mounted therein.
FIG. 16 is a cross-sectional view taken along line 16--16 of FIG. 15.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following detailed description of the preferred embodiments of the present invention, specific terminology is used for the sake of clarity. However, the present invention is not intended to be limited to embodiments incorporating only structures designated by the particular terminology used; the invention includes all technical equivalents for accomplishing a substantially similar purpose in a substantially similar way.
Referring now to the preferred embodiment of the invention shown in FIGS. 1 through 16, and referring specifically to FIG. 1, a furniture system 5 is shown which incorporates two stanchions 100 according to the present invention. The system of FIG. 1 includes an overhead shelf or storage unit 10 supported by two vertical stanchions 100 which rest on and are interconnected to a horizontal work surface 20 of a desk 21.
The work surface 20 may comprise one part of a desk or modular furniture system 7, and in the embodiment of FIG. 1, work surface 20 is shown supported by twin pedestals 22 one of which includes a file drawer 24. Further, the storage unit 10 may include a lower fascia panel 12 and a hinged door 14 for access to the interior of unit 10. However, a stanchion 100 according to the present invention may be employed with any furniture system which includes an overhead portion such as unit 10 of FIG. 1 and a lower portion such as work surface 20 and supporting pedestals 22.
As FIG. 1 readily indicates, use of the stanchions 100 to support an overhead unit 10 leaves a large lateral open space 30 through which adjacent office workers may communicate or which may face an office window. Thus, the stanchions 100 preclude the need for a back structural panel or other support means for an overhead unit 10 when a unit 10 is combined with a desk or other work surface.
FIG. 1 further illustrates that the stanchions 100 are preferably constructed using a "clean" exterior design incorporating front panel 102, top panel 120, and bottom accessory panel 140. Panel 102 is preferably made of plastic. As indicated in FIG. 1 and as shown in detail in FIGS. 3, 5, and 6, the stanchions 100 are generally triangular in cross-section, such that panels 102, 120, and 140 are mounted at an inwardly-facing 45 degree angle with respect to the front edge 26 of work surface 20. When the stanchions 100 form part of an office furniture system such as a desktop and an overhead shelf, the 45 degree angle causes the stanchions 100 to face a worker seated at the desk and facilitates access to the stanchions 100.
The discussion below contains a detailed description of the electrical power routing system employed in conjunction with the stanchions 100. Such electrical power cabling and associated apparatus is concealed within the stanchions 100 and thus is not visible in FIG. 1. However, FIG. 1 shows several electrical and electronic accessories, such as telephone handset 104, clock 106, and electrical receptacle 705, which may be connected to the stanchions 100 using the internal power routing system. The power routing system terminates in a connector concealed behind panel 140, and a hole is provided in panel 140 so that electrical accessories may mate with the appropriate concealed receptacle or connector. The dimensions and placement of the hole within panel 140 vary depending upon the accessory employed. For example, when connection to a telephone handset 104 is desired, panel 140 is provided with a telephone power receptacle 142 mounted in panel 140 to which the handset cable 108 is secured. Other accessories, such as electrical receptacle 705, are mounted directly in panel 140 using a hole of appropriate size.
Any number of office accoutrements may be connected to or secured within panels 102 and 140 and supplied with power either from the power cables concealed within the stanchions 100 or from the building electrical circuitry. By way of example only, such accessories may include a telephone, clock, personal fan, a household-voltage electric power outlet, and other items. As shown in FIG. 1, for example, a clock 106 can be mounted directly in panel 102. The electrical cord and plug of clock 106 can then be connected to one of the building outlets through structure in stanchions 100 and desk 21 which will be described in detail hereinafter.
FIGS. 2 through 6 show the structural details of the stanchion 100. A frame 200 is provided, preferably constructed of formed or extruded metal such as 16 gauge rolled sheet steel. Other material may be used if the material has sufficient structural strength to support an overhead furniture article such as the unit 10 shown in FIG. 1. As shown in FIG. 5, the frame 200 is formed in a generally symmetrical right triangular column, a partial perspective view of which is shown in FIG. 6. Twin, symmetrical back structural panels 202 are provided and are unitarily connected at vertically-oriented right angle bend 204 to form the single unitary frame member 200.
Panels 202 each include symmetrically identical vertical end portions 206 which are folded and formed into an inward facing channel 210 which provides additional structural strength and rigidity. These end portions 206 thus include a short double-thickness wall portion 208 which acts as a rigid vertical column, enhancing the strength of the stanchion 100. Immediately inboard of these double-thickness walls 208 are provided formed channels 210. In addition to providing vertical strength, the vertical channels 210 include an outwardly facing surface 212 to which panel 102 is secured.
As further shown in FIG. 5, the panel 102 is fitted between the inward-facing surfaces 214 of channels 210. To accomplish the fitted arrangement, the inner surface 103 of panel 102 is secured using plural fasteners 216 to an inner front panel 218. In a preferred embodiment as shown in FIGS. 4 and 5, six fasteners 216, which may be conventional rivets, threaded fasteners, or other securement means of known design, are used. Panel 218 includes a metal flange 220 secured to the lower inner face of panel 218, and the ends of flange 220 are fitted against surfaces 214 of channels 210. As shown in FIG. 4, two flanges 220 are provided, one mounted at the top of the inner panel 218 and one along its bottom edge. The flanges 22 further interfit with top panels 120 and bottom panel 140 using a friction fit.
The structure of the top and bottom ends of the stanchion 100 are now described, with specific reference to FIGS. 2 through 6. Details of the top end of stanchion 100 are shown in FIGS. 4 and 5. The top end of a stanchion 100 is formed using inner angle plate 224. The inner angle plate 224 is secured to the inward facing surfaces 201 of back panels 202 using conventional securement means such as welding. The top outer panel 120 is secured to the top surface 221 of panel 222 by means of an inwardly extending lip 228 which is secured at right angles to the top of the front surface of panel 120, as shown in FIG. 4. Panel 224 is provided with plural securement holes 226 shown in FIG. 5, which enable panels 224 and 222 to be secured to an overhead storage unit such as unit 10 of FIG. 1. The exact location and size of holes 226 is not critical, and is generally dependent upon the physical structure of the overhead unit 10, which may vary depending upon the particular furniture configuration in which the stanchions 100 are used.
The structure of the bottom portion of a stanchion 100 is shown in detail in FIGS. 2, 3, 4 and 6. The exact structure and interconnection of parts forming the base of a stanchion 100 is not critical, provided that the base provides sufficient structural strength and rigidity to enable reliable securement to free-standing furniture such as desk 21 of FIG. 1. In a preferred embodiment shown in FIGS. 2 through 6, the bottom portion of stanchion 100 has parts and structural relationships determined, in part, by the parts and structures of the supporting framework of desk 21. As shown in FIG. 6, a desk 21 may include a supporting structure including plural legs 626 having lower ends (not shown) seated on the floor of an office, and upper ends 627. Seated upon and secured to the top ends 627 of legs 626 are a first structural C-channel 630 and a second structural C-channel 632. Channels 630 and 632 are symmetrically identical, and comprise a base plate 640, a raceway channel plate 641 secured at right angles to plate 640 on the inward-facing side of channel 630, a joist plate 644, a top plate 646 secured at right angles to the joist plate 644, and a downwardly extending, elongated lip 648 secured at right angles to top plate 646. In combination, the joist plate 644, the bottom plate 640, and the race way channel plate 642 form a U-shaped raceway 643 useful for retaining and concealing electrical power cabling and other wiring. The top plate 646 provides a relatively broad, flat surface to which a desk top work surface 20 may be secured.
Ends 627 are secured to channels 630 and 632 using conventional securement means such as screws 631. Ends 627 and channels 630 and 632 are further joined using a stanchion securement plate 634; the plate 634 comprises two elongated, flat legs 635 and 637 joined at a right angle.
An angled reinforcement strip 636, comprising two "L"-shaped legs 680 and 681 secured at a right angle at point 683, is secured to plate 634 and the rear surface of ends 627. This reinforcement strip 636 provides additional surface area for securing plate 634 to web plate 628, thus ensuring that plate 634 will not be prone to slippage or misalignment as a result of the large structural stresses placed upon it by overhead unit 10. Extending inward from plate 634 are two symmetrically identical tabs 637 which provide surface area through which securement holes 638 may be drilled. A rear securement hole 639 is also provided in plate 634 at the point where legs 635 and 637 meet. When the stanchion 100 is secured to plate 634, holes 638 and 639 are placed in axial alignment with corresponding holes provided in the bottom plate of the stanchion 100, and suitable threaded fasteners or other securement means are used to join the bottom plate of the stanchion 100 and plate 634.
Other configurations of plate 634 ma be used to accomplish substantially similar purposes, but any desired configuration of plate 634 must include a cut-out cable clearance space 650 as shown in FIG. 6. As the detailed discussion indicates below, the space 650 provides clearance space for electrical power cabling to extend through plate 634 and into the interior of a stanchion 100.
Base plate 300 is secured to the bottom surfaces of channel 212 and double-thickness wall 208 of the columns 210. Conventional securement means such as welding is used. An inner base plate 302 is secured to the top surface of plate 300; the plate 302 is secured to the interior surfaces of frame 200. Plate 302 is drilled with plural securement holes 304 which may be placed in axial alignment with hole 638 and 639 to facilitate securing the stanchion 100 to plate 634 of desk 21. Plate 300 is not drilled with corresponding holes, but rather is provided with plural semi-circular fastener clearance cutouts 306 which enable fasteners protruding through plate 304 to clear plate 300.
Electrical power is supplied to the interior of the stanchion 100 and to accessories connected to the stanchion 100 using a novel combination of electric cable connection and accessory fasteners apparatus 700 shown in FIGS. 7 through 12. The apparatus 700 comprises four main assemblies: an electrical power cable 702 which protrudes upward through space 650 in plate 634 from the base of desk 21; a modular electric power connector 704; a modular electrical receptacle 705; and a mounting plate 706.
The electric power cable 702 is preferably a conventional 8-wire cable such as that commercially available from Pent, Inc. and is unitarily mated to connector 704 which is also commercially available from Pent, Inc., cable 702 and connector 704 together being identified as Pent Inc. part number 225281. The receptacle 705 which is plugged into connector 704 is also conventional and is a stock part commercially available from Pent, Inc. as part number 225169. Receptacle 705 can incorporate a surge protector. Such a receptacle with an integral surge protector is a stock part commercially available from Pent, Inc. as part number 225079. As will be appreciated by those of skill in the art, other features can be incorporated in conventional manner into receptacle 705, such as an emergency light.
The mounting plate 706 comprises plural parts shown in detail in FIGS. 7 through 10. The connector 704 is secured to plate 706 using a rectangular elongated connector bracket 708. As shown in FIGS. 7, 9, and 10, the bracket 708 comprises a center channel 709 and two outwardly facing mounting arms 710. The rear surface 711 of connector 704 is secured to the outward facing surfaces of arms 710 using conventional fastening means, such as rivets or other fasteners. When the connector 704 is secured to bracket 708, the two parts form a unitary structure such that the cable 702 is protected from excessive strain caused by twisting or elongation of the cable.
The bracket 70 is secured to the interior of the stanchion 100 using two fastener tabs 712 which are secured at right angles to the lower ends 713 and 715 of plate 706. Each tab 712 is provided with a fastener hole 714; the plate 706 is secured to plate 304 of the stanchion 100 by placing holes 714 and holes 304 in axial alignment and inserting appropriate fasteners (not shown). Such fasteners may include conventional threaded fasteners such as bolts.
Receptacle 705 is secured to plate 706 using accessory bracket 716. Bracket 716 is secured to plate 706 using plural conventional fasteners 718, such as rivets. The bracket 716 includes two mounting ears 720 extending from its sides at vertical right angles at its upper end 721; receptacle 705 may be secured to the ears 720 using complementary ears 723 which provide a complementary press-fit and hanging arrangement with mounting ears 720. Two accessory abutment brackets 722 are provided and are mounted at right angles parallel to the left and right vertical edges 725 and 727 of bracket 716. The brackets 722 include outwardly facing abutment surfaces 729 against which receptacle 705 can be placed to ensure that receptacle 705 faces outwardly of the stanchion parallel to a vertical plane.
Receptacle 705 is provided with duplex outlets 730 for receiving a conventional plug. As shown in FIG. 1, panel 140 can be provided with an aperture to allow duplex outlets 730 to protrude therethrough. Thus, the rear of an accessory such as a clock 106 can be provided integrally with a conventional two or three-pronged plug (not shown), which plug can be inserted into one of duplex outlets 730. Alternatively, the rear of an accessory such as a clock 106 can be provided integrally with a receptacle similar to receptacle 705 for directly mating to connector 704 in the same manner as receptacle 705. In another alternative, an accessory such as a clock 106 can be conventionally provided with an electrical cord and two or three-pronged plug (not shown), which plug can be inserted into one of duplex outlets 730 for routing power from cable 702 to clock 106.
To retain receptacle 705 in place and provide releasable, demountable securement to bracket 716, a spring clip mount 726 is provided and is secured to the inward-facing face of bracket 716. A pivotable spring clip 750 is attached to mount 726 which releasably engages a locking slot 732 provided at one side of receptacle 705, thus releasably securing receptacle 705 to bracket 716. Thus, a receptacle 705 may be secured to bracket 716 by mating its electrical reception connector 734 with mating electrical plug 736 in the top portion of connector 704, and by engaging spring clip 750 with locking slot 732. Receptacle 705 will then snap into place against abutment bracket 722, thereby releasably securing receptacle 705 in a fixed, vertically oriented position and simultaneously electrically connecting it to cable 702 through connector 704.
As shown in FIGS. 1 and 2, the present invention includes an elongated support bracket 180 mounted along the edge of the rear frame 200. The bracket 180 resembles a standard shelf bracket, and may be used to support a variety of accessories. In a preferred embodiment shown in FIG. 1, the bracket provides support for a shelf 190 which extends between the two stanchions 100 shown in FIG. 1, running parallel to work surface 20. As shown in FIG. 1, the shelf 190 is provided with an undulating or curved front edge 192 and a straight rear edge 194. The curvature of the front edge 192 of the shelf 190 is determined by the proximity of an office worker's chair to the shelf 190. Thus, the shelf 190 is curved inwardly most deeply at the point 196 where an office worker will sit most close to the shelf 190. The curvature diminishes at the ends 198 of the shelf, which are further away from the office worker's typical seat position. This arrangement effectively moves items placed on the ends 198 of the shelf 190 closer to the office worker, while preventing the shelf 190 from interfering with work operations close to the office worker's typical seat position.
Moreover, the shelf 190 is provided with a downwardly beveled front edge 199, shown in FIG. 13. This beveled front edge 199 creates a visual illusion that the shelf 190 is thinner than it actually is. When viewed from a standing position, an observer sees the beveled edge 199 of the shelf 190 rather than the full cross-section of the shelf 190. Thus, a standing observer will perceive that the shelf 190 is thinner than it actually is.
The accessories which may be used in conjunction with the stanchion 100 include accessories occupying only the interior cavity of the stanchion behind panel 140, and larger accessories which also occupy some of the space behind panel 102. An example of the latter type of accessory is the fan and air purification system shown in FIGS. 15 and 16. The fan system 800 includes an air intake filter 802 through which ambient air is drawn by action of motor 804 and fan blades 806 coupled to the motor shaft 808. The air flow created by motor 804 and fan blades 80 is directed out the stanchion through a louver system 810 comprising a plurality of coupled, simultaneously-movable louver panels 812 mounted behind louver housing 814. The louver panels 812 are coupled together in a conventional manner so that panels 812 may be simultaneously rotated left or right to adjust the volume and direction of air flow using louver actuator lever 816. Controls 818 and 820 are provided to enable an office worker to selectively apply power to motor 804 using control 818 and to adjust the speed of motor 804 using control 820 in order to control the airflow rate of the system 800.
As further shown in FIG. 16, each of the louver panels 812 comprises a vertically elongated louver blade 820 having a center pivot 822 and a securement hole 824 provided in a semi-circular inwardly-extending tab 826. Each hole 824 of each blade 820 is interconnected in conventional form, using wire or other rigid connection means, so that moving one blade 820 from the closed position to the open position 828 shown in FIG. 16 will cause all of the blades 820 to simultaneously pivot about point 822 and thereby move to the entirely open or entirely closed position.
Many modifications and variations of the present invention are possible in light of the above teachings and specification. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
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A fully enclosed structural support stanchion for furniture is provided, having an internal cavity which may receive standard modular office furniture electrical service cabling, and which is provided with a demountable front accessory panel to which plural electrical or electronic accessories may be mounted such that a portion of the accessory extends into the stanchion and releasably connects to one end of the standard modular furniture electrical service cabling. The stanchion is constructed with rigid materials so that it can act as a support for an overhead bookshelf or other storage facility, and the stanchion is further provided with a large internal storage cavity into which small office supplies or other articles may be placed and stored behind a hinged, selectively closable door. The stanchion further includes an elongated bracket support which may receive standard shelf brackets, permitting the stanchion to act as a cantilever support for structures such as shelves secured to the shelf brackets. The internal cavity and demountable front-accessory panel of the stanchion may receive electrical service wiring comprising a conventional cable and connector shell rigidly mounted on a support bracket having a spring clip, enabling an electrical receptacle to be quickly and releasably secured to the mounting bracket spring clip while simultaneously mating electrical contacts on the receptacle with electrical contacts provided in the cable connector shell.
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The present invention is directed generally to printing apparatus and more particularly to a printing mechanism including means for cutting a document or recording medium which is to be printed.
The invention is more particularly directed to the cutting device which is arranged preferably in connection with a printing trolley of a printing unit with a rotary cutter being powered by movement of the printing trolley. The cutter cooperates with a counteracting knife edge attached at a platen or printing support base and the cutter is actuated by a control device from an inactive into an active position.
Devices of the type described herein are known in the prior art from DE-GM No. 78 12 759, wherein such a cutting device is described. The device of the prior art includes a rotary cutter which is pushed by a control apparatus from a retracted inactive position in which, normally, printing operation occurs, into an advanced or lowered position at which the cutting process may be performed. The cutting device is connected with a printing unit and cutting movement of the rotary cutter is derived from the motion of the printing trolley relative to the platen or printing support bed. In the known arrangement, the control apparatus is controlled from the inactive into the active position by stops which are rigidly fixed in the housing and approach bevels or similar devices are provided at the platen or printing support bed.
These will ensure that the cutter is brought into contact position with respect to a counteracting knife edge. The arrangement of a special stop firmly fixed in the housing for actuation of the control apparatus and of special approach bevels for rendering the rotary cutter active in the cutting position will require considerable effort.
Thus, there exists in the art a need to improve the control device for moving the rotary cutter from the inactive to the active or cutting position and particularly to simplify the structure of such a mechanism.
Thus, in view of the limitations of the prior art, the present invention is directed toward providing a device, wherein space requirements for repositioning of the rotary cutter may be diminished in order thereby to improve printing width.
A further task to which the present invention is directed relates to the retaining device for the recording medium which is to be cut which, in the prior art arrangement, is directly connected with the rotary cutter. This leads to only a point-shaped fixation of the recording medium occurring there during the cutting process, where one cuts, however, not during the initial cutting. Thereby it cannot be excluded that the recording medium is displaced to some extent at the beginning and at the end of the cutting process so that straight cutting edges cannot be formed.
With the present invention, the device is capable of retaining or holding the recording medium in such a way that deviation of the position of the recording medium at the beginning and at the end of the cutting process is avoided.
SUMMARY OF THE INVENTION
Briefly, the present invention may be described as a cutting mechanism for printing apparatus comprising platen means for supporting a recording medium during a printing operation, printing means including a printing trolley movable along the platen means in a given direction for printing upon the recording medium, rotary cutter means including a rotary cutter blade mounted on the printing means and movable with the printing trolley for cutting the recording medium, counter-acting means on the platen means cooperating with the cutter blade during a cutting operation to facilitate cutting of the recording medium, control means for actuating the rotary cutter means between an active position in operative cooperation with the counteracting means at which a cutting operation may be effected and an inactive position lifted from cooperation with the counteracting means, and spring means applying a spring force to the rotary cutter means in the active position in a direction generally perpendicular to the given direction of travel of the printing means to urge the rotary cutter means against the counteractin means during a cutting operation.
In accordance with the invention, the control means consist of a control device comprising a slide having cam means which moves the rotary cutter from the inactive lifted and retracted positon into the position lowered and advanced so as to be in a cutting attitude. The rotary cutter in the cutting position is retained in contact at a cutting edge of the counteracting means by the spring means acting perpendicularly to the direction of motion of the slide. The slide receives its control movement through coaction with the lateral restrictions which limit movement of the printing trolley along said given direction.
Using the slide with its cam guides as a control device has the advantage that a smooth displacement of the rotary cutter is possible and that the rotary cutter is retained in contact with the counteracting cutting edge only through a relatively weak spring force provided by the spring means. Due to the light contact of the rotary cutter, tolerances in the guidance of the trolley are compensated and wear of the rotary cutter is reduced.
In accordance with an embodiment of the invention a third cam is provided on the cam slide of the control means which imparts to the rotary cutter movement from the retracted position into the advanced position. Through an additional second cam guide, the rotary guide is lifted and lowered, whereby the movement of the rotary cutter due to the first and second cam guides are superimposed in such a way that the rotary cutter is led along the platen means during its movement at the sharp edge of the counteracting means. For retention of the recording medium, the control device acts independently of the rotary cutter upon retention rollers which are arranged on both sides of the rotary cutter. The retention rollers are preferably retained on a balance lever which adjusts itself automatically in the retention position.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objectives attained by its use, reference should be had to the drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a schematic plan view of the printing apparatus with the cutting device in accordance with the present invention;
FIG. 2 is a partial front view showing the cutting device in the inactive position;
FIG. 3 is a front view showing the cutting device in the active or cutting position;
FIG. 4 is a side view of the cutting device of the invention;
FIG. 5 is an exploded view showing portions of the cutting mechanism;
FIG. 6 is a schematic side view showing parts of the mechanism during the cutting process; and
FIG. 7 is a schematic representation showing movement of the rotary cutter into the cutting position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, there is shown printing apparatus in accordance with the present invention including a mechanism for cutting a recording medium to be printed in the printing mechanism.
Referring particularly to FIG. 1, the apparatus of the invention is shown as comprising a pair of guide axles 3 and 4 which direct movement of a printing trolley 5 which is part of the printing means of the apparatus. The guide axles 3 and 4 are arranged to extend between a pair of lateral side stops or plates 1 and 2 which limit the extent of travel of the printing means. A printing head 6 is located upon the printing trolley 5 so that its mouthpiece 7 stands directly in front of a recording medium support pad or platen 8 so that printing upon a recording medium 9 may be performed.
The apparatus is provided with a cutting device 10 which is attached at the printing trolley in such a way that a rotary cutter 11 of the cutting means or device 10 may cooperate with a counteracting cutting edge 20 formed at the platen 8, as is more clearly seen in FIG. 6. An ink ribbon cassette, which consists of two parts 13a and 13b between which an ink ribbon is stretched in front of the platen 8, is additionally fixed between the lateral boundary plates 1 and 2 of the apparatus. For the purpose of guiding the ink ribbon 14, it is directed, on the one hand, around guide bolts 15 and 16 and, on the other hand, so as to lie in front of the mouthpiece 7 forwardly of the apertures through which the print needles of the print mechanism 6 protrude.
The rotary cutting mechanism 10 of the invention is shown in greater detail and will be more particularly described with references to FIGS. 2, 3, 4 and 5.
Referring first to FIG. 2, the cutting mechanism is shown in the inactive position at which the rotary cutter 11 is not positioned to effect a cutting operation and, in this position, the printing head 6, 7 may act upon the recording medium 9 which is fed onto the platen means 8. As will be particularly discerned from FIG. 6, the counteracting means in the form of a counteracting cutting edge 20 is attached at the front side of the platen 8 which cooperates with the rotary cutter 11 and causes shearing off of the recording medium 9 if appropriately controlled.
FIG. 3, on the other hand, shows the cutting device in the active or cutting position, in which position, the rotary cutter 11 operates in cooperation with the counteracting cutting edge 20 in order to shear off individual segments of the printing medium 9.
The printing apparatus is provided with a support part or member 21 which carries all of the parts of the cutting mechanism 10. As is best seen in FIG. 5, the support member 21 is a stirrup-shaped angled part which, at the front and at the rear thereof, consists of bent tabs 22, 23, 24 and 45. The support member 21 is provided with angular bends or tabs 25 and 26 at its sides, with the bends 25 and 26 operating to support and guide different active portions of the cutting mechanism 10.
The control means of the invention for controlling operation of the cutting mechanism 10 comprises a slide 28 which is retained and guided at the ends thereof in the bent tabs 25 and 26 of the support member 21. The slide 28 is formed with two abutment beads 29 and 30 which limit its displacement or movement. The slide 28 pushes with its ends 31 and 32 against the lateral boundaries 1 and 2, which limit movement of the printing trolley 5, whereby the rotary cutter 11 is displaced into the active or inactive position.
The slide 28 has an aperture 33, a cam guide 34, an aperture 35 and a third cam guide 36. The aperture 33 and the cam guide 34 serve for control of the rotary cutter 11. The cam guide 36 serves for control of a set of retaining rollers 37. The rotary cutter is rotatably supported on a lever 39 by means of a bolt 38. The lever 39 is connected with an axle 40 which is supported to be rotatable and axially displaceable in the bent tabs 22 and 24 of the support member 21.
A spring 41 acts upon the axle 40 and also upon the lever 59 as well as upon the rotary cutter 11 in such a way that the rotary cutter rests against the counteracting cutting edge 20 in a resilient manner in the active position as is shown, for example, in FIG. 6. The slide 28 is provided with an angled bend or nose 42 in the area of the aperture 33, while a cam follower 43 is arranged on the axle 40, as can be seen from FIG. 4. Parts 33, 42, 43 together form a first cam guide means which serves for the forward and backward displacement of the rotary cutter 11. If, for example, the slide 28 is moved from left to right, as seen in FIG. 4, then the axle 40 will follow this movement by means of the cam follower 43 and the angled bend 42 in the slide 28 so that the rotary cutter will be moved out of its retracted inactive position into an advanced active position.
It should be observed, as will be discerned from FIG. 4, that the cam follower does not rest at the cam guide 33 of the slide 28, rather it is pressed against the counteracting cutting edge 20 in a fixable manner by the spring 21 which is connected with the lever 39. If, however, the slide 28 is moved from right to left in FIG. 4, then the cam guide 33 of the slide 28 with its angled bend 42 and the cam follower 43 at the axle 40 causes a retraction of the rotary cutter 11 so that it is pushed out of the active position with the counteracting cutting edge. The spring 41 is a relatively weak spring, whereby the wear of the rotary cutter is reduced and the tolerances of the platen are compensated.
In addition to the first cam guide means 33, 42, 43, an additional or second cam guide 34 is provided into which there engages the bolt 38 at the rotary cutter 11. The shape of the cam guide 34, as shown in FIG. 5, will indicate that the rotary cutter 11 is also lifted or lowered by means of the slide 28. The cam guide 33 with the angled bend 42 also has the function to move the rotary cutter 11 forwardly and backwardly, while the cam guide 34 operates to lift and lower the cutter 11. In the advanced lowered position, the cutter 11 is in its effective or active position and, in the retracted or lifted position, the cutter is inactive or ineffective.
The control means consisting of the slide 28 not only controls the lifting and lowering and the forward and rearward movements of the rotary cutter into or out of the cutting position, but it also controls the retention device 37 which operates to move the printing medium 9 in front of and behind the rotary cutter and which is activated independently of the rotary cutter 11. For this purpose, the slide 28 is provided with an additional aperture 35 and a cam guide 36. A control lever 44 is supported upon an axle 46 between the angled tab 23 and an additional angled tab 45 of the support member 21.
The spring 47 biases the control lever 44 as shown in FIG. 5 in a counterclockwise direction. It should be noted that the aperture 35 in the slide 28 is traversed only by the shaft 46, whereby no control operations are effected upon the lever 44. The control function is rather performed by the cam guide 36 which ensures that the control lever 44 can pivot a balance lever 48 from its ineffective position, for example, as shown in FIG. 2, into an active or effective position according to FIG. 3. The balance lever 48 is pivotably supported upon a bolt 49 at the control lever 44 and carries two front and two rear retaining rollers 50, 51, 52 and 53. It should be noted that the axle 38 of the rotary cutter 11 is coaxial with the support axle 49 of the carrier lever 48. Because of this, the two retaining rollers 50, 51 are, on the one hand, assigned to the cutting position and the two retaining rollers 52 and 53 are, on the other hand, assigned to the cutting position of the rotary cutter 11. By means of actuation of the retaining rollers 50-53 over the slide 28 and the cam guide 36, which is independent of the rotary cutter, it is assured that both elements independently of each other may resiliently rest upon the cutting beam or the platen 8. At the same time, the mechanism operates so that the recording medium 9 is already held by the two retaining rollers 50, 51 or 52, 53 before the start or after the termination of the cutting process. In order to improve contact of the two retaining rollers 50, 51 on the one hand, and 52, 53 on the other hand, the inner rollers 51, 52 are provided with a more elastic coating than the outer rollers 50, 53. In this manner, it is assured that at the beginning and at the end of the cutting process, no displacement of the recording medium can occur during cooperation between the rotary cutter 11 and the cutting edge 20 so that a clean cut at right angles to the boundary edges can always be assured.
The cutting operation occurring precisely at this time is shown in FIG. 6 in sectional representation. It will be seen that the rotary cutter 11 rests against the cutting edge of the counteracting cutter 20 only under a very light force of the spring 41.
FIG. 7 depicts in a magnified representation the pattern of movement of the rotary cutter 11 from the lifted or retracted position, according to FIG. 2, into the lowered or active position. The broken line shows that the rotary cutter 11 is advanced and lowered by means of the two cam guides 33 and 34. For performance of the movement, no additional initial positioning bevels or actuation bolts are required at the printer itself. The redirection occurs rather merely by the cooperation of the two ends 31 and 32 of the slide 28 with the two lateral side plates 1 and 2. If it is not necessary to cut, then it is merely necessary for control of the printer trolley 5 to occur in such a manner that reversal of the movement occurs prior to reaching the side plates 1 and 2.
Thus, it will be seen from the foregoing that the present invention is directed to a cutting mechanism for the recording medium in a printing apparatus which is particularly intended to be connected with the printing trolley of the printing unit. The rotary cutter 11 operates together with the counteracting cutting edge 20 in cooperation therewith and it is driven by the movement of the printing trolley 5. The slide 28 with the cam guides 33-36 operates as a control means for displacement of the rotary cutter from the inactive retracted position to the active advanced position. The slide 28 is actuated by abutment of the printing trolley 5 at the two lateral side plates 1, 2, whereby the rotary cutter 11 is lifted and lowered or advanced or retracted. Retaining rollers 50-53 for the recording medium 9 are provided upon a balance lever 48 also actuated by the slide 28 which are arranged on both sides of the cutting position so that the recording medium is held by the retaining rollers 50-53 prior to the start of the cutting process and also after termination thereof.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
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A printing mechanism is provided with a rotary cutter mounted on a printing trolley to enable a recording medium or document to be cut as the printing trolley moves during a printing operation. The recording medium is supported by a platen which has a counteracting edge cooperating with the rotary cutter and a control mechanism operates to actuate the rotary cutter between an active position for cutting and a lifted inactive position with a spring operating to apply a spring force against the rotary cutter tending to urge it against the counteracting edge.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to valve drives for charge-cycling valves of internal combustion engines.
[0003] 2. The Prior Art
[0004] A valve drive of this type, for outlet valves of four-stroke internal combustion engines is described in French Patent No. FR 976.076, in which an outlet valve held in the closed position by a spring force is optionally activated by a first or a second cam, with different lifts of a camshaft. The two cams form an axially displaceable unit that is mounted on the camshaft so as to rotate with it, but to be displaceable. This unit can be displaced into two different positions by a switching fork.
[0005] The first cam is adapted to a charge-cycling process to be controlled, with its elevation curve and angle position relative to the crankshaft, and the second cam is active in a different stroke region than the first cam.
[0006] In the first position, the first cam is in engagement with the tappet of the valve; in the second position, both the first and the second cam are in engagement with the tappet. The first cam constantly controls the usual opening of the outlet valve after expansion and during expulsion of the combustion gases. The second cam, which can be alternatively placed into a position that is ineffective or effective for the outlet valve, opens the outlet valve, in its effective position, in addition to its usual opening during the intake and/or compression stroke. In this way, the exhaust gas also goes into the cylinder, in addition to the charge that was drawn in, in the case of intake throttling with a low fill volume of the cylinder, so that a greater compression is achieved.
[0007] A valve drive for outlet valves of four-stroke internal combustion engines is described in Japanese Patent No. JP 03-202 603, with an outlet cam that has a second elevation and that can be lowered. In its active, outermost position, this elevation opens the outlet valve in addition to its usual opening during the intake and/or compression stroke. In the lowered position, the second elevation is below or at the position of the cam basic circle, and is therefore ineffective.
[0008] It is disadvantageous in these embodiments that due to the alternatively effective or ineffective switching of the second cam, the exhaust gas to be introduced in addition to the charge that is drawn in during the intake and/or compression stroke cannot be precisely metered.
[0009] A variable valve drive is described in German Patent No. DE 101 56 309 A1, in which a cam with only one elevation is in engagement with a cup tappet, and an additional hydraulic activation device is disposed in the cup tappet. With this activation device, which is supplied and controlled by an additional pressure supply unit, additional opening outside the region of engagement of the cam elevation is possible and an enlargement of the valve opening beyond the opening process of the valve by the lift of the cam can be achieved.
[0010] This variable valve drive for outlet valves is used for implementing an exhaust gas feed-back by an additional, multiple opening of the outlet valves outside of the stroke for expulsion of exhaust gas during the intake and/or compression stroke.
[0011] German Patent No. DE 44 24 802 C1 describes a process in which an inlet valve is opened during the stroke for expulsion of exhaust gas, in order to bring about an exhaust gas feed-back from the cylinder into the intake system. The inlet valve is activated by a cam having different elevations. For variable activation of the valve for the additional opening process, independent of the lift of the related cam, the hydraulic cushion of the hydraulic valve place adjustment is utilized.
[0012] It is a disadvantage of the two valve drives described above that in order to control the additional opening of the charge-cycling valves, a separate pressure system with a control device synchronized with the crankshaft is required.
[0013] A method for operating internal combustion engines with variable gas change control times is described in German Patent No. DE 199 05 364 C1. For a direct feed-back of exhaust gas during the intake and compression stroke, the opening time of the outlet valve extends from the end of the expansion stroke over the expulsion stroke to half of the intake stroke, and greater overlap of the valve opening of the outlet and inlet valve occurs.
[0014] To the extent that charge-cycling valves are discussed below, these can be both inlet valves and outlet valves.
SUMMARY OF THE INVENTION
[0015] It is an object of the invention to variably control an additional opening process of a charge-cycling valve, using a mechanical valve drive, which is separate from the charge-cycling stroke to be controlled directly, in order to regulate the exhaust gas feed-back in sensitive manner.
[0016] This object is accomplished by a valve drive for charge-cycling valves of internal combustion engines, which are held in the closed position by spring force and can optionally be activated by a main cam or additionally by a secondary cam of a camshaft. The connection of the main cam with its elevation curve and angle setting is adapted to the crankshaft of a charge-cycling process to be controlled. The secondary cam operates independently of the main cam. There are two engagement surfaces for introducing movements. The engagement surfaces are disposed, in different positions, on a pivot lever mounted on the cylinder head, which activates at least one charge-cycling valve. The first engagement surface on the pivot lever engages the main cam. The second engagement surface on the pivot lever contacts a transfer device for variable adjustment of the valve lift, driven by the second cam.
[0017] The use of a pivot lever to activate one or two charge-cycling valves, in an embodiment according to the invention, having two engagement surfaces for the introduction of lifting movements, allows direct engagement with a first main cam that allows for an opening and closing of one or two valve(s), respectively, for a charge cycle, e.g. intake of fresh gas or expulsion of exhaust gas, and an engagement with a transfer device driven by a second cam, for a variable adjustment of the valve lift for feed-back of exhaust gas into the cylinder chamber or also into the intake pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.
[0019] In the drawings, wherein similar reference characters denote similar elements throughout the several views:
[0020] FIG. 1 shows a side view of the elements of a valve drive according to one embodiment of the invention, with a view in the direction of the progression of the camshaft axis;
[0021] FIG. 2 shows a view from above onto the valve drive according to an embodiment of the invention;
[0022] FIG. 3 shows a perspective view of a valve drive according to an embodiment of the invention;
[0023] FIG. 4 shows a perspective view of a second embodiment of a valve drive according to the invention, having a two-part pivot lever;
[0024] FIG. 5 shows a view from above, onto an embodiment of the valve drive according to FIG. 4 ;
[0025] FIG. 6 shows valve elevation curves with valve drives according to the invention, for inlet valves and
[0026] FIG. 7 shows valve elevation curves with valve drives according to the invention, for outlet valves.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] FIG. 1 shows a side view of the elements of a valve drive according to one embodiment of the invention, with a view in the direction of the progression of the camshaft axis. A camshaft 1 driven by the crankshaft, if necessary by way of an angle adjustment, is mounted in the cylinder head ZK, so as to rotate, with a fixed axis position, and has a fixed position relative to charge-cycling valves 2 and a lift transfer arrangement 3 assigned to them. Lift transfer arrangement 3 , guided in a fixed position, is assigned to charge-cycling valves 2 that are disposed in cylinder head ZK and close by means of spring force. It is formed by a pivot lever 30 mounted on cylinder head ZK and provided with a play equalization element 33 . A main cam 11 of camshaft 1 is in engagement with pivot lever 30 by way of a roll 31 mounted on pivot lever 30 , which roll forms the first engagement surface on pivot lever 30 .
[0028] Camshaft 1 , in addition to the main cam 11 whose elevation curve and angle position relative to the crankshaft is adapted to a charge-cycling process to be controlled, furthermore has a second cam 12 that is active in a different stroke region from main cam 11 .
[0029] The second engagement surface on the pivot lever 30 forms a roll 32 that is mounted on the lever. It stands in engagement with a transfer device 4 driven by second cam 12 , for movements brought about by second cam 12 , for variably adjusting the valve lift. Transfer device 4 has an element 40 whose position can be changed and is disposed in a fixed location in the cylinder head ZK so as to pivot about the pivot axis A 4 , which is in a fixed position, to adjust the valve lift. It forms an adjustable counter-bearing for an intermediate member 5 that is supported on it and is guided during its displacement in this manner. The intermediate member 5 stands in engagement with element 40 , which can change its position, with a non-positive lock, by way of roll 54 mounted, on its control cam 42 as well as with slide supports 55 on the support cams 41 disposed on both sides of the control cam 42 . Support cams 41 are radially offset towards the rear, with a non-positive lock. The outer contour of support cams 41 is formed by an arc about pivot axis A 4 (see FIG. 2 in this regard). An axial guidance of intermediate member 5 is achieved by support cams 41 on both sides that are radially offset towards the rear, as compared with control cam 42 . This arrangement results in a prismatic support of intermediate member 5 on element 40 that is changeable in its position, in the case of every position during the lift movement.
[0030] Furthermore, intermediate member 5 is in engagement with second cam 12 of camshaft 1 , with the roll 53 mounted on it, and furthermore with a roll 32 of lift transfer arrangement 3 assigned to charge-cycling valves 2 , by way of its outer contour 52 .
[0031] Intermediate member 5 is held in engagement with second cam 12 and changeable element 40 , with a non-positive lock, under the effect of the force of a spring F. For this purpose, spring F is supported and guided on intermediate member 5 in a sliding manner in the region of roll 53 , and fixed in place on the cylinder head ZK (not shown).
[0032] FIG. 3 shows a perspective view of the valve drive according to the invention, in connection with all the charge-cycling valves assigned to the cylinder, and their drive mechanisms, as well as an injection nozzle disposed in the center of the combustion chamber.
[0033] FIG. 4 shows a second embodiment of a valve drive according to the invention, with a two-part pivot lever, in a perspective view. FIG. 5 shows this valve drive from above. In contrast to the first embodiment, the pivot lever 30 is configured in two parts and consists of a main pivot arm 301 and a secondary pivot arm 302 , in each instance, whereby these two pivot arms 301 , 302 are articulated independent of one another, but with the same axis, and are in engagement with one of the charge-cycling valves 2 , in each instance.
[0034] Main pivot arm 301 has roll 31 as an engagement surface for the first main cam 11 , on the one hand, and a driver 303 that acts exclusively in the direction of the open valve and stands in engagement with the secondary pivot arm 302 , on the other hand. Secondary pivot arm 302 additionally stands in engagement with transfer device 4 driven by second cam 12 , by way of roll 32 that is mounted on it. Transfer device 4 is the same as the one in the valve drive described according to FIGS. 1 to 3 .
[0035] This second embodiment of a valve drive has the following fundamental functional behavior: The movements brought about by main cam 11 are constantly transferred to both charge-cycling valves 2 . In contrast, the movements brought about by second cam 12 only become effective at charge-cycling valve 2 assigned to the secondary pivot arm 302 , as a function of the setting of the transfer device 4 .
[0036] Fundamentally, the structure of transfer device 4 and its function for varying the valve lift are already known from DE 202 20 138 U1, and need not be described in detail here.
[0037] The embodiment shown in FIGS. 1-3 functions as follows: The charge-cycling valves 2 are closed. Rolls 31 and 53 , in each instance, are in engagement with the basic circle of the main cam 11 and second cam 12 , respectively. In case of a further rotation from this position, in a clockwise direction, roll 53 is first constantly forced in the direction of the opening of the valve, from the elevation of second cam 12 until the outermost cam contour is reached, and subsequently valve 2 is closed by spring force, not shown. During the movement progression, intermediate member 5 glides on support cam 41 and control cam 42 , with line contact, and in the direction of the longitudinal expanse, by way of the roll 32 of lift transfer system 3 . By means of the structure and the set angle position of element 40 with the control cam 42 , an adjustable, variable opening of the two charge-cycling valves 2 is possible. In case of further rotation, main cam 11 moves pivot lever 30 , by way of roll 31 , which lever always opens the two charge-cycling valves 2 at a constant lift, in usual manner.
[0038] With the embodiment shown in FIGS. 4 and 5 , the movements brought about by the main cam 11 are always transferred to both charge-cycling valves 2 . In contrast, movements brought about by second cam 12 only become effective at the charge-cycling valve 2 assigned to secondary pivot arm 302 , as a function of the setting of transfer device 4 .
[0039] According to FIGS. 4 and 5 , the charge-cycling valves 2 of the valve drive are closed. Rolls 31 and 53 are in engagement with the basic circle of main cam 11 or second cam 12 , respectively, in each instance. In case of further rotation of the camshaft 1 in the clockwise direction, from the position shown in the aforementioned figures, roll 53 is first constantly forced in the direction of the opening of the valve, from the elevation of second cam 12 until the outermost cam contour is reached, whereby charge-cycling valve 2 assigned to secondary pivot arm 302 is opened as a function of transfer device 4 , and subsequently closed by means of spring force, not shown.
[0040] With the structure and the set angle position of the element 40 with control cam 42 , in each instance, adjustable, variable opening of charge-cycling valve 2 activated by secondary pivot lever 302 , in each instance, is possible. During this process, main pivot arm 301 continues to support itself on the basic circle of main cam 11 . Charge-cycling valve 2 assigned to the main pivot arm 301 remains closed.
[0041] In case of further rotation, main cam 11 moves main pivot arm 301 with driver 303 , which is in engagement with secondary pivot arm 302 in the direction of the open valve, by way of the roll 31 . In usual manner, the two charge-cycling valves 2 are always opened by the main cam 11 at a constant lift.
[0042] Possible valve elevation curves that can be implemented with the valve drives according to the invention are shown in FIGS. 6 and 7 and will be explained below.
[0043] FIG. 6 shows valve elevation curves of inlet valves with the location in the stroke regions of four-stroke engines that can be implemented with valve drives according to the invention. In this case, the charge-cycling valves 2 are inlet valves.
[0044] With the embodiment according to FIG. 3 , both inlet valves are always activated synchronously. Main cam 11 always opens the two inlet valves at a constant lift during intake, see Ö 11 .
[0045] The adjustable opening of the two inlet valves takes place by way of the second cam 12 and transfer device 4 , see curve group Ö 12 , even during expulsion of the exhaust gases. In this way, exhaust gas feed-back from the cylinder into the intake tract is achieved. If such exhaust gas feed-back is not desired, opening is prevented by second cam 12 , by means of transfer device 4 . Both inlet valves remain in the closed state.
[0046] In the case of an embodiment of the valve drive according to FIG. 4 or 5 , the two inlet valves are always opened at a constant lift during intake, by main cam 11 , see Ö 11 . Adjustable opening only of the inlet valve activated by secondary pivot arm 302 takes place exclusively by way of second cam 12 and transfer device 4 , in accordance with the curve group Ö 12 shown in FIG. 6 . The inlet valve activated by main pivot arm 301 remains closed. With this embodiment, in which only one of the inlet valves is effective for exhaust gas feed-back, more precise metering of the amount of exhaust gas fed back can be achieved.
[0047] FIG. 7 shows valve elevation curves of outlet valves with their location in the stroke regions of four-stroke engines that can be implemented with valve drives according to the invention. In this case, the charge-cycling valves 2 are outlet valves.
[0048] When using an embodiment of the valve drive according to FIG. 3 , the two outlet valves are always activated synchronously. Main cam 11 opens both outlet valves at the end of the expansion stroke, and during expulsion, always at a constant lift, see Ö 11 . The adjustable opening of the two outlet valves, see curve group Ö 12 , can take place by way of second cam 12 and the transfer device 4 , even during the beginning of compression, but after closing of the inlet valves. In this way, exhaust gas feed-back from the exhaust gas tract into the cylinder is achieved.
[0049] If such exhaust gas feed-back is not desired, opening of the outlet valves is prevented by second cam 12 , by means of transfer device 4 . Both outlet valves remain in the closed state.
[0050] When using an embodiment of the valve drive according to FIG. 4 or 5 , both outlet valves are opened by main cam 11 at the end of the expansion stroke and during expulsion, always at a constant lift, see Ö 11 .
[0051] Adjustable opening only of the outlet valve activated by secondary pivot arm 302 takes place exclusively by way of second cam 12 and transfer device 4 , corresponding to curve group Ö 12 shown in FIG. 7 . The outlet valve activated by the main pivot arm 301 remains closed.
[0052] With this embodiment, in which only one of the outlet valves is active for exhaust gas feed-back, it is possible to achieve more precise metering of the amount of exhaust gas fed back, if necessary even an influence on the charge movements in the cylinder chamber.
[0053] If no exhaust gas feed-back is desired, opening of the outlet valve is prevented by second cam 12 , by means of the transfer device 4 .
[0054] To achieve several lifts, second cam 12 can have several elevations that are effective separate from main cam 11 . If the elevations on second cam 12 are different, it is possible to adjust the size of the additional lifts depending on the position of changeable element 40 , in each instance and, for example, to suppress lifts that result from slight elevations on second cam 12 .
[0055] In the latter case, not all the elevations on second cam 12 become effective for opening charge-cycling valves. However, such an embodiment is not shown in any of the Figures.
[0056] Accordingly, while only a few embodiments of the present invention have been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.
REFERENCE SYMBOLS
[0000]
1 camshaft
11 main cam
12 second cam
2 charge-cycling valve
3 lift transfer arrangement
30 pivot lever
31 roll
32 roll
33 play equalization element
301 main pivot arm 301
302 secondary pivot arm
303 driver on 301
4 transfer device for movements brought about by the second cam 12
40 element, changeable in its position, pivotable
41 support cam
42 control cam
5 intermediate member
52 outer contour
53 roll
54 roll
55 slide support
F spring whose force engages at 5 and places [it] against 4 and 12
ZK cylinder head
Ö 11 opening of valves 2 by means of the main cam 11
Ö 12 adjustable opening of valves 2 by the second cam 12
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A valve drive for charge-cycling valves of internal combustion engines, which are held in the closed position by means of spring force, and can optionally be activated by a main cam or additionally by a secondary cam of a camshaft, in which connection the main cam with its elevation curve and angle setting is adapted to the crankshaft of a charge-cycling process to be controlled, and the secondary cam operates separately from the main cam. The drive variably controls an additional opening procedure of a charge-cycling valve, separate from the charge-cycling stroke to be controlled directly, in order to sensitively regulate the exhaust gas feed-back in this manner. The drive has two engagement surfaces for introducing movements on a pivot lever mounted on the cylinder head, which activates at least one charge-cycling valve. The first engagement surface on the pivot lever engages the main cam and the second engagement surface on the pivot lever contacts a transfer device for variable adjustment of the valve lift, driven by the second cam.
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TECHNICAL FIELD OF THE INVENTION
[0001] The technical field of this invention is recording and transmitting digital audio data.
BACKGROUND OF THE INVENTION
[0002] The prior art includes a variety of techniques and algorithms for improving the quality of digitally recorded and transmitted audio data. These techniques include altering audio pitch.
[0003] One prior art technique achieves pitch shifting by seamless time-scale modification (TSM) and restoration of the original time scale through sampling rate conversion. Pitch shifters embedded in karaoke systems use this principle permitting adjustment of the key of a song accompaniment to the singer's voice. Previous approaches to pitch conversion generally employ either: constant pitch shift of the entire signal as seen in common key-shifting algorithms; or complex algorithms that rely on manually labeled databases, speech production models and/or frequency domain processing.
SUMMARY OF THE INVENTION
[0004] The present invention locally controls the pitch of speech and audio signals. The invention uses time scale modification (S-TSM) and a synchronized sampling rate converter that seamlessly switches between different time scale factors. Since the time scale can be adjusted in small steps and transitions between time scales occur seamlessly, this invention provides nearly continuous playback pitch control. The invention is useful in key shifting function in recording studios or karaoke equipment and it can control intonation or fundamental frequency in speech and music synthesis without requiring a speech production model or manual pitch marking.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] These and other aspects of this invention are illustrated in the drawings, in which:
[0006] FIG. 1 illustrates the seamless time scale modification (S-TSM) of this invention continuously receiving input frames containing Sa samples and generating output frames containing Ss samples without changing the original pitch;
[0007] FIG. 2 illustrates an overview of S-TSM processing;
[0008] FIG. 3 illustrates the addition of overlapped frames with fade-in/fade-out windows;
[0009] FIG. 4 illustrates the fine-tuning of the separation Ss between output frames;
[0010] FIG. 5 illustrates the principle of determining optimal offset k;
[0011] FIG. 6 illustrates a system based on Pythagorean tuning using small integer ratios; and
[0012] FIG. 7 illustrates a block diagram of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0013] There are two common approaches to changing the fundamental frequency contour in speech synthesis systems. The first approach uses a speech production model. Voiced speech is approximated as the output of a vocal tract filter fed by an impulse train or another excitation signal source. Controlling the fundamental frequency is relatively straightforward, since it is dictated by the fundamental frequency of the source. However, such systems only work satisfactorily for signals containing pure speech that can be approximated by the model. The second approach is known as PSOLA (pitch-synchronous overlap-add). This approach first marks a speech database containing natural speech utterances. These marks indicate positions in the speech waveform corresponding to fundamental periods. Speech is synthesized by concatenating segments of speech extracted from the database. In order to change the fundamental frequency, distances between marks are changed and the waveform between the marks is warped accordingly. This method usually results in high quality, but pitch marking is a laborious process that cannot be executed automatically.
[0014] FIG. 1 illustrates seamless time scale modification (S-TSM) system 100 . S-TSM 100 continuously receives input frames containing a continuous audio stream of Sa samples 101 and generates output frames containing a continuous audio stream of Ss samples 102 without changing the original pitch. These continuous audio streams include frames that are segments of Sa and Ss and can vary from frame to frame to cope with dynamic time scale changes during playback. If the input consists of a continuous audio stream, the output frames can be concatenated successively without audible artifacts at frame transitions.
[0015] FIG. 2 illustrates the two basic steps involved in audio stream processing. In the analysis step 201 , the input signal is subdivided into overlapping frames (f 1 , f 2 , f 3 . . . ) separated by Sa samples. Note that the larger the value of Sa, the smaller the amount of overlap between successive frames. In the synthesis step 202 the frames resulting from the analysis step are added using a different separation Ss to obtain the output signal. Time scale is reduced when Ss<Sa or increased when Ss>Sa.
[0016] The frame addition operation in synthesis step 202 requires prior multiplication of the frames by fade-in and fade-out window functions. FIG. 3 illustrates an example window function. The window function is valid in different forms but must assume the value 0 at the beginning of the overlapping region 301 and the value 1 at its end 302 , and the sum of the fade-in and fade-out window values must always equal 1. FIG. 3 shows simple ramp functions that satisfy these properties.
[0017] In general, parameters Sa and Ss are set arbitrarily within certain limits in order to achieve the desired time scale modification. Referring back to FIG. 2 , selecting Sa=1024 samples and Ss=512 samples reduces the time scale by half. This results in double speed for a sampled audio signal. In practice the value of Ss must be fine-tuned in order to maximize phase coherence between the frames to be added.
[0018] FIG. 4 illustrates this fine-tuning. An offset value k 401 is added to Ss 402 , resulting in the actual separation Ss+k 403 between output frames. An important part of the algorithm finds the optimal value of offset k that results in maximum coherence between the signal frames to be added.
[0019] FIG. 5 illustrates the process of optimizing k. Consider the regions where the two signal frames to be added overlap, indicated as x 501 and y 502 . The optimal value of offset k is the one that results in maximum coherence between signals x 501 and y 502 by maximizing their similarity. For the example waveforms shown in the FIG. 5 , it is clear that the particular value of k shown results indeed in maximum similarity. Mathematically, similarity can be approximated by a cross-correlation function. In this case, cross-correlation is evaluated for values of k from −k max to k max and the value that results in maximum cross-correlation is selected. Using cross-correlation or other functions as measures of signal similarity has been thoroughly studied in the literature.
[0020] The S-TSM algorithm of the present invention has the additional property that the desired parameters Sa and Ss can be changed in real-time without introducing audible artifacts. There is no discontinuity from frame to frame even when time scales Sa and Ss are changed. A buffering mechanism stores a past history of data and keeps track of the last selected value of k. The deviation from the desired value of Ss by the amount k is always compensated in the following frame and an internal buffer exists as part of the S-TSM processing to absorb such deviations. As a consequence, the S-TSM algorithm always takes exactly the desired numbers of input and output samples regardless of the value of k.
[0021] In principle, Sa and Ss can assume any integer values within a certain range but it is convenient to predefine a set of values relating to desired time scale modification factors. Table 1 defines possible values of Sa and Ss that allow time scale modification factors of 4/8 (0.5×) to 16/8 (2.0×) based upon a sampling frequency of 48 kHz.
[0022] For musical applications a good choice appears to use time scales based on the musical scale covering 1 or 2 octaves of range. Other applications such as speech synthesis do not require such a wide range but finer gradation.
[0023] Note that in Table 1 the number of input samples Sa is the same value of 1024 for all modes. The number of output sample Ss varies from 512 to 2048 and is eventually restored to 1024 by the synchronized sampling rate converter, resulting in the desired pitch modification factor.
[0000] TABLE 1 Time Scale Modification Input Buffer Output Buffer Factor Size (S a ) Size (S s ) 4/8 1024 2048 5/8 1024 1638 6/8 1024 1365 7/8 1024 1170 8/8 1024 1024 9/8 1024 910 10/8 1024 820 11/8 1024 744 12/8 1024 682 13/8 1024 630 14/8 1024 586 15/8 1024 546 16/8 1024 512
The input and output buffer sizes of the S-TSM algorithm shown in Table 1 were conveniently selected to simplify the switching of the sampling rate conversion filter between different modification factors.
[0024] FIG. 6 illustrates the general case of sampling rate conversion by a rational factor Z/D, where Z is the up-sampling factor and D is the down-sampling (decimation) factor. Input 601 is up-sampled by up-sampler 603 . Low pass filter 604 filters the output of up-sampler 603 . Down-sampler 605 down-samples the filtered signal producing output signal 602 . Conversion factor table 607 determines the up-sampling factor Z and the down-sampling factor D dependent on the desired time-scale modification. Controller 606 controls the cut-off frequency of low pass filter 604 based on the factors selected by conversion factor table 607 .
[0025] Sampling rate conversion must provide for seamless processing producing no audible artifacts from frame to frame due to transitions between different conversion factors. Use of an FIR (finite impulse response) filter easily satisfies this requirement as the low-pass filter with a delay line that encompasses the longest filter.
[0026] In the preferred embodiment the up-sampling factor varies from 4 to 16 while the down-sampling factor is always 8 as shown in Table 1. The cut-off frequency fc of low-pass filter 604 must correspond in the digital domain to the smallest value out of π/8 or π/n, where n ranges from 4 to 16. Care must be taken to maintain signal continuity upon filter switching by means of shared filter delay lines and filter gain compensation.
[0027] For a karaoke system, a larger number of sampling rate conversions based on a musical scale is desirable. Pythagorean tuning is based on similar small integer ratios. The system illustrated in FIG. 6 may used in this case. Most modern systems use an equal temperament musical scale based on the (irrational) twelfth root of two. In this case a direct interpolation method may be more advantageous than the equivalent up-sampling/down-sampling conversion based on a rational approximation. In either approach using a 1024 sample buffer for Sa and an integer size for Ss allows the pitch to be accurately shifted to within two cents ( 1/100th of a musical half-step) of any equal tempered musical interval within one octave up or down. If further accuracy is desired, a different value of Sa can be used with the corresponding best value of Ss.
[0028] FIG. 7 illustrates the block diagram of the pitch control system. The input audio stream 701 is split into frames numbered i=1, i=2 and so forth. Sa(i) is the input frame size. In the preferred embodiment the frame size is set to the constant value of 1024 samples. F 0 ( i ) is the original value of the fundamental frequency and k(i) 707 is the pitch change factor that can be set for each frame. Pitch change factor k 707 is selected according to method illustrated in FIG. 5 . S-TSM 703 outputs Ss(i) samples, where Ss(i)=k(i)*Sa(i). Sampling rate converter SRC 705 is synchronized with k(i) 707 and restores the original number of samples Sa(i) by changing the fundamental frequency to k(i)Fo(i). Note that a particular pitch change factor will remain constant for 1024 samples or 21 ms at a 48 kHz sampling rate. This is sufficiently short to be considered instantaneous for most applications.
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This invention locally controls the pitch of speech and audio signals. The invention is based on a seamless time scale modification (S-TSM) scheme connected to a synchronized sampling rate converter that switches between different time scale factors in a seamless manner and controls pitch during playback in a nearly continuous way.
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CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority of German Patent Application No: 10 2006 026 883.0, filed on Jun. 9, 2006, the subject matter of which is incorporated herein by reference.
BACKGROUND
The present invention relates to a process for hardening stainless steel, as well as a molten salt bath for realizing this process.
Owing to its excellent corrosion-resistance properties, stainless steel is used for constructing chemical apparatuses, in the field of food technology, in the petrochemical industry for offshore applications, for the ship and airplane construction, in architecture, for constructing houses and technical equipment, as well as for many other industrial applications.
Corrosion-resistant stainless steel is understood to refer to an iron material with at least 13% by weight of chromium added by alloying. In most cases, nickel, titanium and molybdenum are also added to the iron alloy, e.g. as explained in the Steel Instruction Leaflet 821 entitled “EDELSTAHL ROSTFREI-EIGENSCHAFTEN-INFORMATIONSSTELLE EDELSTAHL” [Corrosion-Resistant Stainless Steel-Characteristics-Information Source for Stainless Steel] PF 102205, 40013 Düsseldorf; www.edelstahl-rostfrei.de, and in P. Gümpel et al. “ROSTFREIE STÄHLE” [Corrosion-Resistant Steels], Expert Publishing House, Volume 349, Renningen Malmsheim 1998. Typical austenitic stainless steels are the alloys of steels 1.4301 or 1.4571 and have the following compositions in % by weight:
1.4301: 0.05 C; 0.5 Si; 1.4 Mn; 18.5 Cr; 9.5 Ni
1.4571: 0.03 C; 0.5 Si; 1.7 Mn; 17.0 Cr; 11.2 Ni; 2.2 Mo; 0.1 Ti.
If the chromium content is less than 13% by weight, the steel in general is not sufficiently corrosion-resistant to be considered stainless steel. The metallic chromium content of the steel therefore represents an important criterion for the corrosion resistance, as explained in P. Gümpel et al. “ROSTFREIE STÄHLE” [Corrosion-Resistant Steels], Expert Publishing House, Volume 349, Renningen Malmsheim 1998.
The fact that most generally used types of stainless steel such as 1.4301, 1.4441, 1.4541, or 1.4575 are rather soft steels and are therefore subject to scratching of the surface by hard particles such as dust or sand is a major disadvantage. Most stainless steels, apart from the very specialized martensitic stainless steels, cannot be hardened by using physical processes such as annealing and quenching. The low surface hardness frequently prevents the use of the stainless steel. Most types of stainless steel furthermore have a tendency to strong adhesion through friction, meaning two surfaces sliding against each other are welded together as a result of adhesion.
The surface of stainless steel can be enriched with nitrogen by subjecting it to a thermo-chemical treatment, e.g. nitriding or nitro-carbureting in gas (in an ammonia atmosphere), in plasma (with nitrogen/argon) or in the molten salt bath (molten cyanate salts), during which iron nitrides and chromium nitrides are formed. In contrast to physically deposited layers or layers formed by electroplating, the resulting layers are formed from the material itself, meaning they are not externally deposited and therefore have extreme adhesive strength. Hard layers with a thickness ranging from 5 to 50 μm are thus formed, depending on the treatment length. The hardness of such nitrided or nitro-carbureted layers on stainless steel reaches values above 1000 units on the Vickers hardness scale because of the high hardness of the resulting iron nitrides and chromium nitrides.
The problem with depositing such nitrided or nitro-carbureted layers on stainless steel in practical operations is that the layers are hard, to be sure, but lose their corrosion-resistance because of the relatively high treatment temperature for the nitriding or nitro-carbureting treatment, which is in the range of 580° C. At this temperature, the diffused-in elements nitrogen and carbon form in the component surface region stable chromium nitrides (CrN) and/or chromium carbides (Cr 7 C 3 ) together with the chromium. The free chromium, which is absolutely required for the corrosion resistance, is thus extracted from the stainless steel matrix up to a depth of approximately 50 μm below the surface and is converted to chromium nitride or chromium carbide. The component surface is hardened due to the iron nitride and chromium nitride that forms, but also becomes susceptible to corrosion. Such layers are worn down and/or eroded quickly during use as a result of corrosion.
The following methods are currently in use for avoiding this problem.
It is known that the surface hardness of stainless steel can be improved through electroplating, e.g. nickel-plating or depositing of physical layers with the PVD method (physical vapor deposition). These processes, however, require an alien material to be deposited on the steel surface, meaning the steel surface is no longer the surface in contact with the corrosive or abrasive medium. As a result, there are problems with the adhesion and the corrosion-resistance. These processes are consequently not widely used to improve the hardness and corrosion-resistance of stainless steel.
A hard and simultaneously corrosion-resistant layer can be formed with thermo-chemical deposition on stainless steel and using the so-called Kolsterisieren® (kolsterizing process). This process is mentioned, for example, in the information leaflet Kolsterisieren®—Anticorrosion Surface Hardening of Austenitic Corrosion-Resistant Steel—from the company Bodycote Hardiff bv, Parimariboweg 45, NL-7333 Apeldoorn, info@hardiff.de, as well as in M. Wägner, “STEIGERUNG DER VERSCHLEISS-FESTIGKEIT NICHTROSTENDER AUST. STÄHLE” [Improving the Corrosion-Resistance of Non-Rusting Aust. Steels], in “STAHL” [Steel], Issue No. 2 (2004) 40-43. The process conditions are not described either in patent literature or in the scientific literature accessible to the public. Components treated in this way have a hard, wear-resistant layer with a thickness of between 10 and 20 μm while the corrosion-resistance of the basic material is preserved. Components that are Kolsterisiert® (kolsterized) must not be heated above 400° C. since they otherwise loose their corrosion resistance.
Using the plasma nitriding process, for example described in H.-J. Spies et al. “MAT.-WISS. U. WERKSTOFFTECHNIK 30 [Material Knowledge and Material Technology 30] (1999) 457-464, as well as in Y. Sun, T. Bell et al. “The Response of Austenitic Stainless Steel to Low Temp. Plasma Nitriding Heat Treatment of Metals,” Issue No. 1 (1999) 9-16, or the process of vacuum carburization as described, for example, in “OBERFLÄCHENHÄRTUNG VON AUSTENITISCHEN STÄHLEN UNTER BEIBEHALTUNG DER KORROSIONSBESTÄNDIGKEIT” [Surface Hardening of Austenitic Steels while Maintaining Corrosion-Resistance] by D. Günther, F. Hoffmann, M. Jung, P. Mayr in “HÄRTEREI-TECHN. MITT.” [Hardening Technology Information], 56 (2001) 74-83, it is possible to generate an over-saturated solution of nitrogen and/or carbon at low temperatures in the surface of components made from stainless steel. This solution has the desired characteristics, meaning the higher hardness along with unchanged corrosion resistance.
However, both processes require high apparatus expenditure and high investment and energy costs, as well as the use of specially trained personnel, in most cases scientifically trained personnel, for operating the systems.
A process for the case-hardening of rust-resistant steel is known from German Patent Application DE 35 01 409 A1. With this process, the surface of the work piece to be hardened is initially activated by treating it with an acid and is then treated inside a heated fluidized bed containing active nitrogen and preferably also active carbon, capable of diffusing into the work piece.
A process for carburizing austenitic metal is described in German Patent Application DE 695 10 719 T2. According to this process, the metal is heated and kept in a fluorine-containing or fluoride-containing gas atmosphere prior to the carburization. The carburizing of the metal then takes place at a maximum temperature of 680° C.
SUMMARY
It is an object of the present invention to provide a cost-effective, efficient process for hardening stainless steel while simultaneously retaining as much as possible the corrosion resistance of the stainless steel.
The above and other objects are accomplished according to the invention wherein there is provided in one embodiment a molten salt bath used for hardening a surface of stainless steel, comprising, by weight, the following components::
30-60% potassium chloride (KCl), 20-40% lithium chloride (LiCl), 15-30% an activator substance selected from the group consisting of barium chloride (BaCl 2 ), strontium chloride (SrCl 2 ), magnesium chloride (MgCl 2 ), calcium chloride (CaCl 2 ) and admixtures thereof, and 0.2-25% a carbon-donating substance selected from the group consisting of a free cyanide, a complex cyanide and admixtures.
The invention additionally relates to a process for hardening a work piece of stainless steel through diffusing of the elements carbon and/or nitrogen into the work piece surfaces. According to an embodiment of the process, the work piece is submerged into and subjected to a molten salt bath as described above for a period ranging from 15 minutes to 240 hours and at temperatures below 450° C.
The present invention avoids high apparatus and energy expenditures and uses an relatively easy process that can be carried out even by less qualified personnel.
The invention furthermore considerably reduces the tendency of stainless steel to frictional adhesion, meaning cold-welding, and thus also the adhesive wear. The hardness of the stainless steel surface is increased from values of 200-300 Vickers to values of up to 1000 Vickers, thereby making it extremely scratch-resistant.
The use of the molten salt bath according to the invention makes it possible to harden stainless steel while maintaining its corrosion resistance.
The process according to the invention is based on the following principle.
Stainless steel is typically present in the form of austenitic steel, meaning the iron matrix has the structure of an austenite, a cubical face-centered lattice. Non-metal elements such as nitrogen and carbon can be present in this lattice in a solid solution. If carbon or nitrogen or both elements are successfully diffused into the surface of an austenitic stainless steel and are kept there in a solid saturated or even over-saturated solution, then two effects will occur:
(a) If carbon is diffused in below the chromium carbide forming temperature (420-440° C.) and nitrogen is diffused in below the chromium nitride forming temperature (350-370° C.), no carbides or nitrides of the chromium will form. As a result, no chromium is extracted from the alloy matrix in the region of the diffusion layer and the corrosion resistance of the stainless steel is preserved.
(b) The diffused-in elements expand the austenitic lattice and result in high compressive stress in the diffusion zone, which in turn leads to a considerable increase in the hardness. In scientific literature, this is referred to as expanded austenite or S-phase, which can have a hardness of up to 1000 on the Vickers scale. The term S-phase is explained, for example, in Y. Sun, T. Bell et al. in the “The Response of Austenitic Stainless Steel to Low Temp. Plasma Nitriding Heat Treatment of Metals,” Issue No. 1 (1999) 9-16.
These processes are used for the present invention by utilizing the inventive molten salt bath as reactive medium and as heat-transfer medium.
The molten salt bath according to the invention contains components which can release carbon and/or nitrogen capable of diffusing, as well as suitable activator substances that cause the release at low temperatures of nitrogen and/or carbon capable of diffusing. It is essential in this connection that the treatment temperatures in the molten salt bath are below 450° C. and it is especially advantageous if they are lowered to values below the temperature where chromium carbide (420-440° C.) or chromium nitride (350-370° C.) forms, so as to prevent or mostly prevent the forming of nitrides and carbides in the steel matrix.
The concentration of active carbon-donating or nitrogen-donating compounds in the form of complex or free cyanides in the molten salt bath according to the invention is very high when compared to the concentration of corresponding compounds (ammonia, methane, carbon dioxide) in gaseous atmospheres or in plasma. The relatively long treatment periods necessary for the process according to the invention result from the fact that the diffusion speed of C and N is a function of the temperature and drops significantly for temperatures below 450° C. Long diffusion times of 12 to 60 hours are necessary at the required low temperatures to avoid the forming of chromium carbide and chromium nitride. Austenitic rust-resistant steels or so-called duplex steels (ferritic—austenitic steels) are highly insensitive to such long treatment periods and for all practical purposes do not change their other mechanical characteristics or the structure.
The molten salt bath is composed of a mixture of potassium chloride, barium chloride and lithium chloride salts. Alternatively, a molten salt bath of strontium chloride, potassium chloride and lithium chloride can also be used. Magnesium chloride and/or calcium chloride, for example in amounts of 0.1 to 10% by weight, can furthermore be used as an alternative to barium chloride or strontium chloride or in addition thereto. The melting points for the eutectic mixture of these salts are in the range of 320° C. to 350° C. Yellow potassium hexacyanoferrate (II), meaning K 4 Fe(CN) 6 is added to these salts as the carbon-donating substance in amounts ranging from 0.2 to 25% by weight, in particular ranging from 1 to 25% by weight. The salt, which contains 3 mol equivalents of water of crystallization in the delivered form, should be dried at least 12-24 hours at 120-140° C. before it is added, so as to remove the water of crystallization. Alternatively, red potassium hexacyanoferrate (III) K 3 Fe(CN) 6 , which does not contain water of crystallization, can be added to the molten salt bath. The complex cyanide is preferably added in an amount ranging from 2 to 10% by weight.
Alternatively or in addition to the aforementioned complex iron cyanides, other complex metal cyanides can also be used as carbon-donating substances. Examples for this are tetracyanonickel or tetracyanozinc compounds such as Na 2 Ni(CN) 4 or Na 2 Zn(CN) 4 .
Sodium cyanide and/or potassium cyanide in the free form can furthermore be added in place of the complex, non-toxic iron cyanides or metal cyanides, in amounts ranging from 0.1 to 25% by weight and preferably ranging from 3 to 10% by weight. The results are similar as for the use of complex cyanides, wherein mixtures of complex and free cyanides can also be used.
Using molten salt baths containing complex cyanides has the advantage that no toxic substances must be handled since hexacyanoferrate per se is not toxic. Free cyanides have the advantage of a low price, making this process advantageous if a waste water detoxification system exists for the cyanides.
The course of the process of diffusing carbon and nitrogen from the molten salt bath into the stainless steel and the function of the activator substances in this process is explained in the following with the example of a molten salt bath containing iron cyanides as carbon-donating substances. The operating temperature of the molten salt bath for this embodiment ranges from 350 to 420° C. At this temperature, the complex iron cyanides decompose as shown in the following:
K 4 Fe(CN) 6 →Fe+2C+4KCN+N 2
K 3 Fe(CN) 6 →Fe+3C+3KCN+3/2N 2
However, the decomposition occurs very slowly. The carbon formed during the decomposition diffuses into the austenitic stainless steel to be hardened and, at temperatures below 420° C., remains there in the form of a solid, saturated or over-saturated solution. Austenite has a high capacity for dissolving carbon and a lower capacity for dissolving nitrogen.
A portion of the nitrogen that forms is also diffused into the stainless steel surface. If the treatment temperature is below 350-370° C., then the nitrogen, in the same way as the carbon, remains in a solid solution. If the temperature is between 370 and 420° C., the nitrogen forms chromium nitride with the alloy element chromium and thus can potentially reduce the corrosion resistance of the stainless steel surface. Nevertheless, the forming of chromium carbide is still avoided in this temperature range, so that little chromium is extracted from the alloy matrix of the stainless steel despite the forming of chromium nitride at this temperature range. The reduction in the corrosion resistance of the stainless steel can therefore still be acceptable. To further improve the corrosion resistance at this temperature range, the diffusing in of nitrogen should be avoided and only carbon in a solid solution should be diffused into the component surface, wherein temperatures of up to 440° C. can be used. With temperatures below 370° C., on the other hand, nitrogen and carbon can be diffused in jointly in the form of a solid solution, without causing chromium nitride or chromium carbide to form.
The following reactions are furthermore possible in the molten salt bath:
2KCN+O 2 →2KOCN
4KOCN→K2CO 3 +2KCN+CO+2<N>
2KCN+2O 2 →K 2 CO 3 +CO+N 2
2CO+Fe→Fe 3 C+CO 2
Cyanide ions, which form during the decomposition of the complex metal salt, are oxidized by the atmospheric oxygen that is present throughout the molten salt bath and form cyanate ions, which can decompose and form carbon monoxide and nitrogen. Cyanate ions in most cases are the source for diffusion-capable nitrogen. Cyanide ions can oxidize further and form carbonate ions, wherein carbon monoxide is formed. Carbon monoxide can react further and form carbon dioxide by releasing diffusion-capable carbon.
In addition, cyanide can react with barium ions of the activator substance contained as barium chloride in the molten salt bath and can form barium cyanide Ba(CN) 2 which transforms to barium cyanamide BaNCN. In the process, carbon is released which can diffuse into the components.
BaCl 2 +2KCN→Ba(CN) 2 +2KCl
Ba(CN) 2 →BaNCN+<C>
BaNCN+3/2O 2 →BaCO 3 +N 2
The barium cyanamide reacts further with the atmospheric oxygen to form barium carbonate and nitrogen, which is released. Similar reactions can be expected from strontium, calcium and magnesium, provided strontium chloride, calcium chloride and/or magnesium chloride is used as an activator substance. With the process according to the invention, the alkaline earth metals in the form of halogenides consequently form activator substances, which cause the release of nitrogen and carbon capable of diffusing in the temperature range specified for the process according to the invention. The diffusing of the required amount of carbon into the stainless steel surface is not possible without using at least one alkaline earth element from the family magnesium, calcium, strontium and barium. A similar role is played by the element lithium, which acts in a similar manner as the alkaline earth metals and also functions as an activator for the diffusion of carbon:
2LiCl+2KCN→2LiCN+2KCl
2LiCN→Li 2 NCN+<C>
Li 2 NCN+3/2O 2 →Li 2 CO 3 +N 2
The remaining alkaline metals Na, K, Rb and Cs do not have this effect.
The cited reactions explain the mechanism for transferring carbon and nitrogen to the treated components of stainless steel while these are submerged in eutectic molten salt baths composed of alkaline earth chlorides and lithium salts. They also explain the occurrence of small amounts of cyanate ions, for example in amounts of 0.1 to 10% by weight, and carbonate ions, for example in a concentration of 0.1 to 10% by weight, as a result of the oxidation processes after the molten salt bath has been in operation for a specific period.
An analytical control of the molten salt baths according to the invention can be realized as follows: The change in the concentration of active components (complex cyanides or free cyanide) can be monitored with the aid of potentiometric titration. In the case of K 4 Fe(CN) 6 , titration can occur with Cer(IV) sulfate solution. Free cyanide is easy to determine with nickel(II)sulfate. Used cyanide or complex cyanide is correspondingly replenished.
An inert gas such as argon, nitrogen, or carbon dioxide can be introduced into the molten salt bath according to the invention for the displacement of air and to prevent oxidation of the free and/or complex cyanide. It is particularly advantageous for displacing air and preventing oxidation of the free and complex cyanide if the molten salt bath is operated in a closed retort and using nitrogen, argon or carbon dioxide as protective gas.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the invention will be further understood from the following detailed description of the preferred embodiments with reference to the accompanying drawings, showing in:
FIG. 1 is a representation of a cross section through a stainless steel 1.4571 sample, which is hardened in a molten salt bath according to the invention.
FIG. 2 is an element depth profile analysis of a stainless steel 1.4541 that is hardened in a molten salt bath according to the invention.
FIG. 3 illustrates the hardening progress in dependence on the penetration depth in the surface area of a stainless steel 1.4541 sample treated in the molten salt bath according to the invention.
DETAILED DESCRIPTION
Example 1
Inside a crucible of heat-resistant steel, for example 1.4828 steel, 42 kg dry potassium chloride, 34 kg dry lithium chloride and 20 kg barium chloride siccum are weighed in and loosely mixed together. All salts must have a residual moisture content of less than 0.3% by weight. The mixture is heated to 400° C. and results in a water-clear melt to which is slowly added the amount of 4 kg potassium hexacyanoferrate (II) that was previously dried for 12 hours at 140° C. inside a muffle furnace. When feeding in the potassium hexacyanoferrate (II), a very small amount of carbon is precipitated out along the crucible wall and on the surface of the molten salt bath. This carbon is skimmed off with a slotted spoon, leaving a water-clear melt which is then heated to an operating temperature of 400° C. Work pieces of stainless steel 1.4571 (material X6CrNiMoTil7-12.2), which weigh 10 kg and are attached to steel wires, are then submerged in and subjected to the effect of the molten salt bath for a period of 48 hours.
This treatment results in a 20-22 μm thick diffusion layer on the surface of the treated components and samples, which can be shown with the aid of a metallographic polish of cross section and by etching it with the reagent V2A etching agent. The V2A etching agent consists of a mixture of 100 ml water and 100 ml hydrochloric acid concentrate (HCl, 30%) and 0.3% “Vogels Reagenz” [Vogel reagent]. The Vogel reagent consists of a mixture of 60% 2-methoxy-2-propanol (H3C-O-CH2Oh-CH3), 5% thiourea (H2N-CS-NH2), 5% nonyl-phenol-ethoxylate residual ethanol. The cross section is shown with the photograph in FIG. 1 , enlarged by the power of 500. The surface hardness of this layer is determined to be 642-715 HV (0.5) and/or 1100-1210 HV (0.025). The element distribution within the layer can be determined with the glow discharge spectroscopy (GDOES) and is shown with the example in FIG. 2 . FIG. 2 shows the penetration depth for the elements N, C, Fe, Cr 2 , Ni, Mo in the surface of the work piece that is hardened in the molten salt bath, meaning the mass concentrations of these elements in percentages are plotted in μm, in dependence on the penetration depth in the work piece. The curve courses for Fe, O, Cr 2 and Ni, shown in FIG. 2 , respectively, relate to mass concentrations of 100% while the curve courses for C, Mo relate to mass concentrations of 10% and the curve course of N relates to a mass concentration of 25%. FIG. 2 shows that carbon is diffused to a depth of approximately 25-27 μm while nitrogen is diffused somewhat less deep. The carbon and nitrogen amounts detected in the surface layer of the work piece are not present in the form of nitrides or carbides, but for the most part are present in the form of nitrogen and carbon in a solid, oversaturated solution.
FIG. 3 shows the progression of the hardening for this work piece in dependence on the depth (in μm), which is measured with the Vickers method under a test load of 0.010 kp (10 gram). A comparison of FIGS. 2 and 3 shows a significant improvement of the hardness of the work piece surface layer, into which nitrogen and carbon are diffused with the aid of the molten salt bath.
Example 2
The amounts of 43 kg dry potassium chloride, 30 kg dry lithium chloride, 17 kg strontium chloride siccum, and 3 kg barium chloride siccum are weighed into a crucible of heat-resistant steel and are loosely mixed. All salts must have a residual moisture content of less than 0.3% by weight. The mixture is heated to 400° C. and results in a water-clear melt to which is slowly added the amount of 7 kg potassium hexacyanoferrate (II) that is previously dried for 12 hours at 140° C. inside a muffle furnace. The operating temperature for the resulting water-clear melt is then lowered to 370° C. Work pieces of stainless steel 1.4301 that weigh 10 kg and are attached to steel wires are submerged into and are subjected to the influence of this molten salt bath for a period of 24-48 hours.
Depending on the length of time, the treatment results in a 10-25 μm thick diffusion layer on the surface of the treated components and samples. This can be shown with a metallographic cross section and by etching it with the V2A etching agent.
Example 3
The amounts of 37 kg dry potassium chloride, 26 kg dry lithium chloride, and 17 kg strontium chloride siccum are weighed into a crucible of heat-resistant steel and are loosely mixed together. All salts must have a residual moisture content of less than 0.3% by weight. The mixture is heated to 400° C. and results in a water-clear melt to which are slowly added the amounts of 10 kg KCN and 10 kg NaCN. The resulting melt is heated to an operating temperature of 400-410° C. Work pieces of stainless steel 1.4301, weighing 10 kg and attached to steel wires, are submerged into and subjected to the influence of this molten salt bath for a period of 24 hours.
The treatment results in a diffusion layer with a thickness of approximately 10 μm on the surface of the treated components and samples, which can be shown with a metallographic cross section and etching with the V2A etching agent. The hardness of this layer is determined to be 620 HV (0.5).
Example 4
The amounts of 42 kg dry potassium chloride, 34 kg dry lithium chloride, 10 kg barium chloride siccum and 10 kg strontium chloride siccum are weighed into a crucible of heat-resistant steel and are loosely mixed together. All salts must have a residual moisture content of less than 0.3% by weight. The mixture is heated to 400° C. and results in a water-clear melt to which is slowly added the amount of 4 kg K 3 Fe(CN) 6 . A water-clear melt forms, which is heated to an operating temperature of 400-410° C. Work pieces of stainless steel 1.4301 and 14541, weighing 10 kg and attached to steel wires, are submerged into and subjected to the influence of this molten salt bath for a period of 24 hours.
Example 5
The amounts of 42 kg dry potassium chloride, 34 kg dry lithium chloride, 10 kg barium chloride siccum and 2 kg strontium chloride siccum are weighed into a crucible of heat-resistant steel and are loosely mixed together. All salts must have a residual moisture content of less than 0.3% by weight. The mixture is heated to 400° C. and results in a water-clear melt to which are slowly added the amounts of 4 kg K 3 Fe(CN) 6 as well as 4 kg KCN and 4 kg NaCN. A clear melt forms, which is then heated to an operating temperature of 400-410° C. Work pieces of stainless steel 1.4301 and 1.4541 that weigh 10 kg each and are attached to steel wires are submerged into and subjected to the influence of this molten salt bath for a period of 24 hours.
Example 6
A stainless steel work piece is submerged into a molten salt bath for a period ranging from 15 minutes to 240 hours and at temperatures below 450° C. The molten salt bath comprises, by weight, the following components: about 40% KCl, about 33% LiCl, about 2% BaCl 2 , about 20% SrCl 2 , and about 5% potassium hexacyanoferrate (II).
Example 7
A stainless steel work piece is submerged into a molten salt bath for a period ranging from 15 minutes to 240 hours and at temperatures below 450° C. The molten salt bath comprises, by weight, the following components: about 44% KCl, about 30% LiCl, about 5% BaCl 2 , about 15% SrCl 2 , about 3% potassium hexacyanoferrate (II), about 2% NaCN, and about 1% KCN.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and that the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
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A process for hardening a work piece of stainless steel through diffusion of the elements carbon and/or nitrogen into the work piece surfaces. The work piece is submerged into a molten salt bath and subjected to the molten salt bath for a period ranging from 15 minutes to 240 hours at temperatures below 450° C. In addition to potassium chloride and lithium chloride, the molten salt bath contains an activator substance consisting of barium chloride, strontium chloride, magnesium chloride and/or calcium chloride, and a free or complex cyanide as carbon-donating substance.
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BACKGROUND OF THE INVENTION
The present invention concerns an automatic feeder for textile machines and a related feeding method. More particularly, the present invention concerns an automatic continuous feeder of bobbins or reels of sliver to a series of spinning machines, together with the related feeding method.
In present methods for feeding spinning machines or other textile machines,, a storage area is provided for the bobbins or reels of sliver. From the storage area the bobbins or reels are taken to the spinning machine, where the sliver undergoes known processes of stretching and twisting. The principal disadvantage of this method is that, besides involving a considerable amount of manual labor during transport, it requires a storage area to keep the various types of sliver until they are used. Consequently, large areas are dedicated for this "non-productive" purpose which can more productively be used in some other manner.
Accordingly, there is a need for a device and a method for feeding spinning or other textile machines which minimizes the labor necessary for this operation, as well as the storage space needed for the bobbins and reels which are to be fed.
An object of the present invention is to overcome the above-mentioned problems and provide a feeder for textile machines in which the storage function is performed by a structure which, while housing a large number of bobbins of various kinds, occupies a limited space and automatically feeds the textile machines.
A further object of the present invention is to provide a method for feeding textile machines in which the bobbins are stored in a small space and are sent automatically to the textile machines to be fed.
SUMMARY OF THE INVENTION
The present invention discloses a feeder for textile machines having transport means for the continuous transport and supply of a plurality of bobbins; a sliver winder for winding empty ones of the bobbins with a length of sliver; marking means for marking the wound bobbins with a removable code corresponding to predetermined characteristics of the length of sliver; an inlet for transferring the wound bobbins from the sliver winder to the transport means; bobbin handling means for loading, unloading and positioning the plurality of bobbins on the textile machines; a station for inserting the wound bobbins onto the bobbin handling means; reading means at the insertion station for recognizing the code marked on the wound bobbins; a station for removing the empty bobbins from the bobbin handling means; and an outlet for transferring the empty bobbins from the transport means to the sliver winder.
Preferably, the feeder of the present invention further includes means at the removing station for zeroing the code on the empty bobbins, and reading means at the outlet for recognizing the zeroed code on the empty bobbins.
In addition, the present invention discloses a method for automatically feeding a plurality of bobbins to textile machines, in particular, spinning machines, comprising the steps of winding each of the plurality of bobbins with a length of sliver on a sliver winder marking the wound bobbins with a removable code corresponding to predetermined characteristics of the length of sliver; transferring the wound bobbins from the sliver winder to a transport means and transporting them on the transport means; reading the code on the wound bobbins and removing the wound bobbins from the transport means for loading onto a corresponding one of the textile machines according to the code; unwinding the length of sliver from each of the wound bobbins in the textile machines; removing the empty bobbins from the textile machines and zeroing the code thereon; transferring the unwound bobbins onto the transport means; and removing the unwound bobbins from the transport means for insertion into the sliver winder.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features, objects and advantages of the present invention will be more readily understood from the following description when taken with reference to the accompanying drawings in which,
FIG. 1 is a schematic plan view of an automatic feeder according to the present invention being employed with three spinning machines;
FIG. 2 is a partial side view of a structure according to the present invention for loading and unloading the spinning machines of FIG. 1;
FIG. 3 is a partial plan view of the structure of FIG. 2;
FIG. 4 is a partial side view of a detail of the device of FIGS. 2 and 3 showing the indicator and reader for indicating whether the bobbins are full or empty; and
FIG. 5 is a side view of a guide tube broken away in partial cross-section to show the photocell for indicating the presence of sliver in the guide tube.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a schematic embodiment of a feeder device according to the present invention. The feeder device includes an endless transport structure 1 which continually transports a plurality of bobbins 2 along a track between a winder sliver 4 and a plurality of textile machines; in particular, spinning machines 3.
The bobbins 2 differ in that some are "full", i.e., have sliver wound around them, while others are empty (for convenience, the empty bobbins are marked with an "X" in the drawings although they carry the same reference numeral as the full ones). The full bobbins may have different types and counts of sliver. Although the bobbins may contain yarn or sliver, depending on the type of textile machine being fed, the invention herein will be described with respect to feeding bobbins full of sliver from a sliver winding machine to a spinning machine. However, it will be apparent to those of ordinary skill in the art that when the bobbins contain yarn, the invention herein may be used to feed bobbins full of yarn from, for example, a spinning machine to a different textile machine, such as a loom.
In FIG. 1, the sliver winder 4 has three positions: one for empty bobbins, one for full bobbins, and one for those bobbins on which the winder is winding sliver. Any form of winder that can perform this function can be utilized.
A device 7 is provided downstream of the sliver winder 4 for marking the full bobbins before releasing them onto the endless transporter 1 through an insertion station 5. The marking can be performed in any manner, such as mechanically, electronically, etc. A similar station 6 acts upstream of the sliver winder 4 at the point of arrival of the empty bobbins 2 as they come off the endless transporter 1.
To connect with the spinning machines, the endless transporter 1 has a series of branches each of which extend from the endless transporter 1 to a structure 8 which serves to load, unload and position the bobbins on the spinning machines 3. As can be seen from FIG. 1, each spinning machine has one structure 8 and a pair of sub-branches 9 and 9'.
In each of these pairs, a first sub-branch 9 acts as a buffer and loading station for full bobbins 2 coming into the structure 8, while a second sub-branch 9' acts as an unloading station to unload empty bobbins 2 from structure 8 onto the endless transporter 1.
As previously mentioned, each full bobbin coming off the sliver winder 4 is marked by the device 7 according to the type and count of the sliver it carries. In each of the loading stations there is a reader 10 which reads the markings and is set to load the correct bobbin 2 onto the appropriate structure 8 and spinning machine 3. Thus, the reader 10 selects the appropriate bobbins 2 from those being transported by the endless transporter 1 and sends them to the correct loading station 9.
At the exit from structure 8 there is a zeroing device 11 which, before the empty bobbins 2 are reloaded onto the endless transporter 1, zeros the markings or, more accurately, replaces them with a "zero" marking characteristic of empty bobbins. A reader 12 located on the endless transporter 1 next to exit station 6 is set for the characteristic "zero" marking and, hence, identifies the empty bobbins and sends them to station 6.
For reasons which will be made clear below, it may happen that bobbins which are still partially full may be marked empty. Recognition of these bobbins is entrusted to a sensor (not shown) which removes the empty bobbins and collects them separately.
A partial view of structure 8 is shown in FIGS. 2 and 3. It should be noted that structure 8 is symmetrical about the axis M--M and that the part not seen is identical to the part shown. The structure 8 provides an apparatus for positioning the bobbins 2 on a spinning machine 3, the apparatus comprising a double line of spindles 14 freely rotating on their axes and located in fixed positions along two spaced parallel beams 13. Each spindle has an enlarged base 15 to support the base of the bobbin 2 when the bobbin is housed on the spindle 14.
Upstanding stanchions on the beams 13 support rails 16 along which runs a trolley 17. Hanging from the trolley 17 is a device 18 for transporting the bobbins along the positioning apparatus.
A supporting rail 19 positioned between and higher than the beams 13 includes a series of spaced indicators 20 which indicate the condition of the bobbins 2 on the positioning apparatus. A reader 26 of the indicators 20 travels along the rail 19. This reader 26 is integral with the central controlling part of the mobile device 18, stopping the device 18 whenever the indicators 20 signal to do so.
On the sides of the central part of device 18 are two mechanical arms 21 and 22 pointing in opposite directions for lifting, transporting and releasing the full or empty bobbins 2. Both of these arms may move in a vertical direction along the central part of device 18, which in turn can oscillate and rotate along its own vertical axis, as best indicated by the arrow in FIG. 3. Additionally, the arm 21, which is used only for full bobbins, includes a device to rotate the bobbin 2 once the bobbin 2 is positioned on a spindle 14, thereby facilitating the initial spinning of the bobbin 2. Such a device obviously could also be mounted on the second arm 22, thus making either arm capable of moving the full bobbins.
With the same purpose of facilitating the initial unwinding of the bobbin 2, a preferred embodiment includes an end picker device 23 on the arm 21 and a number of guide tubes 24, one for each bobbin 2, to feed the end of the sliver to the tensioning bar of the corresponding spinning machine 3. At one end of each guide tube 24, preferably at the end nearest the tensioning bar, there is a photocell 25 whose position is shown in greater detail in FIG. 5. As with any typical photocell, one portion of photocell 25 consists of a light source, while the other portion of photocell 25 consists of a receiving cell or photocell detector. The output of photocell 25 is connected to a light source that constitutes the indicator 20 for determining the condition of the bobbins 2. While a bobbin 2 is unwinding and its associated sliver is passing through the guide tube 24 the light source is obstructed and the electric circuit is interrupted. However, when the bobbin is empty and there is no longer any sliver passing through the guide tube 24, the light source impinges upon the photocell detector to complete the circuit and the related indicator 20 is activated.
The location of rail 19 and reader 26 in relation to the guide tubes 24 and indicators 20 is shown in greater detail in FIG. 4. As can readily be seen, the rail 19 is supported by the stanchions 27 at a position above but close to the mouths of the guide tubes 24. The indicators 20 are located on both vertical sides of the rail 19, there being a pair indicators 20 for every pair of guide tubes 24. It is worth noting that although the bobbins 2 are located on the two beams 13 disposed on opposite sides of rail 19 to save space, the guide tubes 24 carry the sliver to one spinning machine only.
During the operation of the automatic feeder of the present invention, the bobbins 2 wound by the sliver winder 4 are marked by the marking device 7 according to the count and type of sliver wound upon them. Following winding, the bobbins 2 are admitted onto the endless transporter 1 by the inserting station 5.
Once on the endless transporter 1, the bobbins 2 are circulated with the other bobbins already present, the other bobbins being marked either like or unlike the last inserted bobbins. All of the bobbins 2 are read by the readers 10. Should a spinning machine 3 require more bobbins 2, the respective reader 10 will pass appropriately marked bobbins 2 to the buffer and loading stage 9 of the related structure 8. Should the bobbins 2 not have the correct markings, they will continue on the endless transporter 1 until they meet the appropriate reader 10.
Those bobbins 2 which are fed to the buffer and loading stage 9 will typically encounter other bobbins. After a period of time which can be long or short depending on the number of other bobbins encountered, each bobbin will be lifted by the arm 21 of the mobile device 18 and taken along the positioning apparatus to a spindle 14 where there is an empty bobbin. Those sites at which spindles 14 have empty bobbins are determined by reader 26 as it passes across indicators 20 on rail 19.
Trolley 17 spans the pair of rails 16, carrying the mobile device 18 in a longitudinal direction therealong. In order to provide a more compact apparatus, mobile device 18 is designed to rotate about a central axis so that arms 21 and 22 do not interfere with the bobbins 2 positioned on the beams 13. Thus, as mobile device 18 moves longitudinally along the rails 16, it may be rotated so that arms 21 and 22 are parallel to the direction of travel. As each guide tube 24 runs out of sliver, its respective photocell 25 activates the associated indicator 20. Mobile device 18 stops as it encounters an indicator 20 activated in this manner. It then rotates on its own axis so that arm 22 may remove empty bobbin 2 from spindle 14. Having removed the empty bobbin 2, device 18 then rotates again so that arm 21 may place a full bobbin 2 on the spindle 14 in place of the empty one.
After placing the full bobbin 2 on the spindle 14, the mechanism housed in the arm 21 spins the bobbin 2 in the unwinding direction as device 23 inserts the end of the sliver into the guide tube 24, feeding it along the entire length of the guide tube 24. As the sliver exits the guide tube 24, it interrupts the circuit of photocell 25, thereby deactivating the indicator 20. Conversely, once the bobbin 2 is unwound completely, the sliver does not obstruct the light beam from impinging upon the receiving cell of photocell 25, so that the indicator 20 is activated to signal the presence of an empty bobbin 2.
As the empty bobbin 2 is removed from spindle 14 by the arm 22, it is zeroed by device 11 (which could also be housed in the arm 22) and sent to circulate on the endless transporter 1. Arriving at reader 12, the empty and zeroed bobbin 2 is sent to station 6 where it exits the endless transporter 1. At that point a checking sensor (not shown) determines whether the bobbin 2 is really empty or has been marked so only because the sliver had broken. In those cases where the bobbin 2 is actually empty, the bobbin 2 is directed to the sliver winder 4 to be rewound and sent once again to the endless transporter 1. In those cases where a quantity of the sliver remains on the bobbin 2 due to the breakage of the sliver, the bobbin 2 is segregated from the empty bobbins by the checking sensor and brought to the attention of the machine operator.
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An endless structure for the continuous transport of a plurality of bobbins is disposed for operative association with one or more textile machines such as, for instance, spinning machines. Each bobbin is marked with a code according to whether the bobbin is empty or wound with sliver, as well as the type and count of the sliver wound thereabout. As the bobbin travels on the endless transport structure the code is read and the wound bobbins are directed to an appropriate textile machine for unwinding. Empty bobbins are removed from the textile machine and carried by the endless transport structure to an exit station. At the exit station, empty bobbins are loaded into a sliver winder for rewinding with sliver. Once wound, the bobbins are marked with a new code and inserted back onto the endless transport structure.
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FIELD OF THE INVENTION
The invention relates to a yarn feeding device.
BACKGROUND OF THE INVENTION
Yarn feeding devices operating with adjustable yarn separation and a backturn detent for the winding element are known in practice by prior notorious use and e.g. disclosed in WO/A-99/14149. Such yarn feeding devices predominantly are used for processing special yarn materials, e.g. for supplying the weft yarn when weaving filtering or bossing fabric webs for paper or cardboard production. Due to the elasticity or rigidity of the yarn material or due to certain mechanical conditions a tendency of a backturning motion of the winding element occurs counter to the winding on direction when the winding element stops. This might result in the formation of loops or kinks in the yarn or might lead to overlaps between the yarn windings on the storage drum and finally in operation failures. The backturn detent is provided between the motor housing and the drive shaft or in the supporting bearing of the stationary rod cage and prevents this undesirable backturn motion of the winding element. The yarn separation, i.e. the intermediate distance between respective two adjacent yarn windings on the storage drum in such cases with delicate yarn material is an extremely important measure to properly control the yarn. As the magnitude of yarn separation (pitch) is not the same for all yarn qualities and yarn types but is dependent on each yarn type or each yarn material, respectively, and individually depends on different factors, the magnitude of the yarn separation has to be adjusted in order to achieve optimum conditions for the respective yarn being processed. The yarn separation results from an advance motion in a direction oriented to the withdrawal end of the storage drum, which advance motion is imparted on to the yarn windings on the storage drum. For that function it is a common principle to rotate by the drive shaft an eccentric and skew cylinder inside the advance rod cage. The advance rod cage of the stationary storage drum is supported rotatably on said cylinder. The rotation of said cylinder generates a wobbling motion of the advance rod cage. Thanks to the wobbling motion the rods of the advance rod cage first move outwardly beyond the rods of the supporting rod cage, simultaneously are moved forward relative to the winding on location of the yarn, and finally re-enter inwardly behind the rods of the support rod cage, reverse their motion direction and return to their home position. In order to vary the magnitude of the yarn separation either the radial plane of the maximum eccentricity is rotated about the axis of the drive shaft relative to the plane of the skew inclination of the cylinder to vary the phase offset between those two radial planes, or the magnitude of the skewness position is varied at a given phase offset between the two radial planes. In case of the first, technically simpler method, a bushing carrying the skew cylinder surface is rotated on an eccentric element which either is provided on the drive shaft or even is formed at the drive shaft. In this case, for adjustments the bushing is held against rotation from outside and the drive shaft is rotated inside with the help of the winding element and in one or the other rotational directions. However, the mentioned backturn there only allows a rotation of the drive shaft in one direction of rotation, namely in the winding on direction. For this reason an adjustment of the yarn separation in the locked direction of rotation cannot be carried out by simply rotating the driving shaft by means of the winding element.
It is an object of the invention to provide a yarn feeding device of the kind as disclosed at the beginning at which the yarn separation despite the presence of a backturn detent can be increased or decreased by simply rotating the driving shaft.
As intended, the backturn detent prevents the undesired backturning motion of the winding element since the driving shaft is blocked in backturning direction by the backturn detent and the advance rod cage inside the stationary storage drum. According to this the desired safety effect of the backturn detent is reliably achieved. As for the adjustment of the yarn separation the advance rod cage has to be held while the drive shaft is rotated in one or the other direction of rotation. The locking action of the backturn detent in backturn rotational direction optionally even can be used to provide the relative rotation between the planes of the skew inclination position and the eccentricity. For that reason it is comfortably possible to increase or decrease the yarn separation despite the action of the backturn detent and only by rotating the drive shaft, e.g. by hand, and with the help of the winding element in the respectively required direction. Extremely comfortable and quick adjustments even can be carried out in the blocked direction of rotation without an auxiliary tool just with the help of the backturn detent.
The backturn detent can be provided in the advance support in a structurally simple and space saving manner.
As relative rotational movements between the drive shaft and the stationary advance rod cage occur between the inner race and the outer race of a usual ball bearing or between the bearing surfaces of a plain bearing, it is expedient to provide the backturn detent between the races or between the bearing surfaces, respectively. In this case expediently a conventionally available bearing just containing the backturn detent can be used. The backturn detent can be equipped by locking elements, similar to the free wheel assembly of a bicycle driving hub, which locking elements engage automatically only in case of or prior to the not desired rotational motion. As a consequence the backturn detent can be made as a rotational freewheel device locking automatically in one rotational direction or as a overtaking rotational clutch locking automatically in one rotational direction. Alternatively, the backturn detent may be located between the advance bearing and the drive shaft such that the advance bearing is supported by the backturn detent on the drive shaft or the adjustable element of the yarn separation mechanism respectively.
As a further alternative the backturn detent may be provided parallel to the advance bearing and at a side of the latter. The locking effect is imparted between the bearing races or the bearing surfaces, respectively, or directly between the element and the advance rod cage, which element is provided for rotational adjustment on the drive shaft.
For a comfortable and gradual adjustment of the yarn separation the axis of eccentricity and the axis of the skew inclination are adjustable in relation to each other and/or relative to the axis of the drive shaft.
The axis of the eccentricity and the skew inclination axis are adjusted in relation to each other in rotational direction of the drive shaft in each sense of rotation, in order to allow to use a rotational motion of the drive shaft for the adjustment, which rotational motion may be imparted manually. In this it is expedient to integrate the axis of eccentricity into the drive shaft and to constitute the axis of the skew inclination by a separate element mounted on the drive shaft for its rotational adjustments.
In a plain bearing even the bearing surfaces could be located skew or eccentrically with respect to the axis of the drive shaft. In this case the inner bearing sleeve is constituting the element necessary for the adjustment of the yarn separation, which element they can be rotated relative to the drive shaft.
The phase offset between the skew inclination position and the eccentricity is varied by relative rotational adjustments such that an increase or decrease or even a complete nullification of the yarn separation results.
In a structurally simple way a bushing is provided at a carrying surface of the drive shaft such that the bushing can be rotated on the drive shaft and can be fixed in the respective desired rotational position. The bushing constitutes an element of the yarn separation adjusting yarn mechanism which element can be adjusted by rotation. In this case either the carrying surface of the drive shaft or the counterstay surface of the bushing may be formed eccentrically. The respective other of both surfaces in this case then is located in a skew inclined position.
Expediently, the advance bearing is provided on the bushing without the possibility to be rotated. Furthermore, a rotational locking socket is provided for engagement of an adjustment tool in order to hold the bushing in case of an adjustment of the yarn separation and when the drive shaft is rotated relative to the bushing by means of the winding element.
An adjustable friction clutch between the bushing and the drive shaft allows a comfortable and simple handling. The friction connection of the friction clutch only needs to be strong enough so that the bushing reliably is taken with in case of normal rotation of the drive shaft, and just so strong that the backturn locking force is unable to overcome the friction force of the friction clutch.
At least two axially spaced apart roller bearings or plain bearings are provided to achieve a stable support of the advance rod cage. The backturn detent, however, only needs to be provided in one of both bearings. If desired, however, each bearing of the advance support could be equipped by backturn detents.
A simple handling of the yarn feeding device in case of an adjustment of the yarn separation is possible, if the adjustment tool is constituted by an on-board pin adjustable in the front end of the storage drum between an engaging position in the rotation locking socket and a passive position. In case that the pin is pre-loaded by a spring, e.g. towards its passive position, an adjustment process can be carried out easily, because the pin only need to be pressed counter to the spring force into its engaging position, before the drive shaft is rotated accordingly. Later, by spring force, the pin automatically returns into its passive position.
In order to avoid an excessive adjustment expediently a stop arrangement ought to be provided for limiting the relative rotational adjustment stroke of the bushing on the drive shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will be described with the help of the drawing. In the drawing:
FIG. 1 is a longitudinal axial section of components of a yarn feeding device, the yarn feeding device including an adjustable yarn separation and backturn detent.
DETAILED DESCRIPTION
A yarn feeding device F in FIG. 1 has a motor housing 1 containing an electromotor 2 driving a drive shaft W about an axis X in one selected direction of rotation. A winding element 3 is provided at drive shaft W, e.g. a winding tube, terminating outside of motor housing 1 and extending obliquely outwards from hollow drive shaft W. Winding element 3 in this case is incorporated into a so-called winding disk 4 which is carried by drive shaft W and is located between motor housing 1 and a storage drum 6 which storage drum is supported via the drive shaft W at motor housing 1 . Drive shaft W functions as the carrier of storage drum 6 and has, for this purpose, a coaxial extension 5 .
Storage drum 6 is combined from two interengaging rod cages, namely of a supporting rod cage 7 having axial rods 8 spaced apart in circumferential direction, and an advance rod cage 28 having axial rods 9 respectively provided in the interspaces between rods 8 . Support rod cage 7 has a stationary front end 24 and is located on a hub 10 which is supported rotatably on the extension 5 by a support bearing 11 (e.g. two roller bearings) coaxially with axis X of drive shaft W.
To hinder storage drum 6 against rotation with the rotating drive shaft W, co-operating permanent magnets 12 , 13 , as well known, are provided in the motor housing 1 and in hub 10 , respectively (stationary storage drum).
The rods 9 of the advance rod cage 28 are provided at a common hub 14 . The hub 14 is supported by a bushing B rotatably seated on drive shaft W in an advance bearing 15 provided eccentrically and skew or inclined relative to the axis X of drive shaft W. The bushing B is seated on a support surface 16 which is cylindrical and located eccentrically relative to the axis X. Cylindrical support surface 16 is formed on extension 5 or is constituted by a not shown member provided on extension 5 . An eccenter axis X 1 of support surface 16 is distanced by a measure e from axis X. Another cylindrical support surface 17 is formed at the periphery of bushing B and is skew and inclined relative to axes X and X 1 (indicated by the dash dotted inclination axis X 2 ).
In the drawing the eccenter axis X 1 and the inclined axis X 2 , for illustration purposes only, are shown in the drawing plane. In order to achieve the yarn separation Z between the yarn windings of the yarn Y wound by winding element 3 onto storage drum 6 , however, a phase offset in rotational direction of drive shaft W has to be provided between the plane containing the axes X, X 1 and the plane containing the inclination axis X 2 . In order to increase, decrease or completely nullify the yarn separation Z the above-mentioned phase offset between the inclination axis X 2 and the eccenter X 1 is to be varied in the respective direction of rotation. A friction clutch R is provided between the bushing B and the drive shaft W, e.g. in the form of a spring package 19 loading the free front end of the bushing B which spring package 19 is pre-loaded by a tensioning screw 18 inserted into the set back free end of the drive shaft W. The spring package 19 couples the bushing B with a predetermined rotation resistance with the drive shaft W.
Furthermore, a rotation-locking socket 21 is provided in the advance bearing 15 , e.g. at a ring flange 20 which may, e.g., be coupled to the bushing B in rotational direction.
An on-board adjustment tool 22 is located in the stationary front end 24 of storage drum 6 . The adjustment tool 22 has the form of a pin which can be brought into an engaging position into rotation locking socket 21 counter to spring force from the shown passive position. In the shown embodiment the advance bearing 15 consists of two axially spaced apart roller bearings. Of the roller bearings the roller bearing 29 facing towards the free end of the drive shaft W is equipped with a backturn detent D. The roller bearing 29 comprises an inner race 25 and an outer race 26 and roller bodies 27 located therebetween. The backturn detent D is functionally integrated between the inner race and the outer race 25 , 26 . Alternatively, the advance bearing 15 instead could include one or two plain bearings having co-operating slide surfaces.
Even though the detail structure of the backturn detent D is not shown, it is to be noted that it is a freely available rotational freewheel or an overtake rotational clutch (sprag clutch) containing locking elements which automatically move into a locking engagement when a rotation tends to occur in the undesired rotational direction. In the shown embodiment the backturn detent D is integrated into the advance bearing 15 . It is, however, possible to incorporate the backturn detent into the roller bearing shown in FIG. 1 on the left side, or even to equip both roller bearings with a respective backturn detent. Furthermore, it is possible, to provide the backturn detent D between the inner race 25 and the bushing B, or to provide it parallel to the respective bearing and at the side of the same.
Finally, a stop assembly 30 is provided between the bushing B and the drive shaft W for limiting the rotational stroke of the bushing B relative to drive shaft W.
In operation of the yarn feeding device F the rotating winding element 3 is supplying the yarn Y onto the storage drum 6 . Due to the skew and eccentric support surface 17 of the bushing B rotating with the drive shaft W the inner race 25 is carrying out a rotating wobbling motion. As the stationary support rod cage 7 is hindered by the co-operating permanent magnets 12 , 13 to rotate with the drive shaft, also the advance rod cage 28 is hindered by the mutually inter-engaging rods 8 and 9 from rotating with the drive shaft.
Between the inner race 25 and the outer race 26 a rotational motion can take place in only one direction of rotation. At the same time tilting motions derived from the wobbling motion of the inner race 25 are transmitted into the rods 9 which effect the advance motion of the yarn windings and by this produces the adjusted yarn separation Z.
If the electromotor 2 is stopped a tendency of a backturn motion of the winding element 3 counter to the former winding on direction can occur, e.g. due to tension in the yarn Y. However, the backturn detent D then is coupling the inner race 25 to the outer race 26 and blocks the drive shaft W in this undesired direction of rotation against the hub 14 of the advance rod cage 28 . A backturn motion is prevented.
In case that the yarn separation Z is to be varied, i.e. is to be increased, decreased or completely to be nullified, first the electromotor 2 is stopped. Then the winding disk 4 is rotated manually and at the same time a frontally located button is pressed to insert the tool 22 into the rotation locking socket 21 . As a consequence of the friction connection of the friction clutch R the drive shaft W or the winding disk 4 , respectively, can no longer be rotated freely. As soon as the friction resistance of the friction clutch R is overcome, however, the support surface 16 can be rotated with the drive shaft W within the bushing B, while the bushing B is locked by the tool 22 . Within the rotational stroke determined by the stopping assembly 30 the respective desired adjustment of the yarn separation Z can be carried out. As soon as the tool 22 is set free, or the button is released which is provided in the front side 24 to actuate the tool 22 , respectively, the return spring moves the tool 22 back into the shown passive position, preferably assisted by a slight manual rotational movement of the winding disk 4 in one or the other direction of rotation. Then the yarn feeding device F again is ready to operate.
As an alternative for the shown adjustment tool 22 a separate adjustment tool could be inserted from outside between the interengaging rods 8 , 9 or even through one of the rods into a then modified rotation locking socket 21 to allow to hold the bushing B against rotation. Basically, the backturn detent D is active in one direction of rotation of the drive shaft W and parallel to the adjustment tool 22 . This has the effect that also the backturn detent D supports the bushing B in this direction of rotation against rotation at advance rod cage 28 and, in turn, at the storage drum 6 . In case that a desired adjustment of the yarn separation Z needs only a rotational movement of the drive shaft W in the rotational direction locked by the backturn detent D, then adjustment tool 22 does not need to be actuated. Such adjustments can be carried out by using the locking function of the backturn detent D instead.
In case that the operational direction of rotation of the winding element 3 is to be reversed, either the roller bearing 29 containing the backturn detent D has to be reversed, or a respective roller bearing 29 is to be mounted containing a backturn detent acting in the opposite direction of rotation.
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The invention relates to a yarn feeding device with a stationary storage drum and an adjustable yarn pitch. The yarn feeding device comprises a motor housing, a drive shaft of a winding element and a storage drum. Said storage drum consists of meshing finger-shaped cages. The finger-shaped advance cage has an advance bushing that is eccentric and skew with respect to the drive shaft. A backturn detent for the take-up element is mounted in said advance cage. The backturn detent is furthermore interposed between the finger-shaped advance cage and the drive shaft.
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BRIEF SUMMARY OF THE INVENTION
This invention relates to the interconnection of cables, ropes, wires or like (all hereinafter included in the term "strands" unless the context otherwise admits) at points where they intersect or adjoin one another.
A typical example of this interconnection is found in the case of nets, such as those made of wire cables or textile ropes which are used as climbing nets, for instance in children's playgrounds or the like.
If the construction of the net is such that parts of the strands can run in parallel at the nodal points of the net they can be interconnected by clamping sleeves, for example of known oval form, into which the strands are threaded. After this threading the clamping sleeves are plastically deformed under pressure to produce a firm jointing of the two strands. The threading procedure involves disadvantages although these can be to some extent avoided by using c-shaped clamping means which are deformed similarly to the aforementioned oval clamping sleeve so that two or even more strands, e.g. ropes or cables, passing therethrough can be firmly connected together. Moreover an adjacent grip can be applied by such clamping means.
When however the strands cross at right angles the aforesaid means can no longer be used. In this instance to provide an interconnection at the intersections it is known to thread the strands through a ring which is disposed in the plane determined by the crossing lengths and the latter are introduced through the ring in such a way that it in each case is clamped between one outer face of the ring and the other strand length.
Threading into the ring in this way is however awkward. If for example a netting structure is to be made from a single length of cable or rope it is necessary to pull the whole of the cable or rope to be plaited through the ring each time. Since the dimensions of the ring is made very narrow to increase the mutual clamping effect this operation is very troublesome and extremely time wasting.
There is an arrangement which can be used for clamping intersecting cable lengths. The clamping device used here comprises essentially two parts. The first part comprises a plate with four pliable lugs which are arranged star fashion and which, after being bent, embrace the crossing lengths of rope against the other part of the device, a counter plate, so that the lengths of cable, fed in diagonally, are clamped between the two plates. The bendable lugs have to be comparatively thin in this arrangement so as to allow for bending without breaking. As a result the grip is very limited.
Protection against corrosion is also difficult in this prior arrangement. If for example galvanised steel plates are used for the parts of the clamping device, the surface protection is immediately damaged during the bending of the lugs. The use of aluminium or other less corrosion-prone material is no solution because of the reduced grip of these materials.
It is an object of the present invention to provide means for connecting strands of ropes or cables, particularly where used in a net construction, which can readily be produced.
A further object is to devise a connector for the purpose indicated which is simple and inexpensive to produce and in which the expenditure in assembly is small.
Another object is to provide an arrangement which will give an absolutely secure connection at the crossing or intersection point which will be adequate to sustain those forces which are likely to be applied through the rope, cable, or other strands.
In meeting this object the present invention provides a connector for the purposes described above which is formed from a blank of unitary construction having at each of the opposite sides thereof a U-shaped passage-forming opening for each of the two strands, the orientation of the openings being suited to the orientation of the strands, and after deformation of the blank, in which the walls bounding the openings are pressed against one another to form a ring enclosing each strand, the outer dimensions of the connector are substantially the same overall.
This expedient provided by the invention is surprisingly simple. The connector may for example be of aluminium, but alternatively of other materials which can be deformed under pressure. In special cases for example a steel connector can be used. There is only a single body involved and this accelerates the assembly. In this assembly the strands have only to be laid in the openings whereafter the connector is deformed to produce a firm and safe connection of the latter to the strands and these latter to the connector itself.
It is of particular advantage that the compression of the connector blank, and thus the creation of the clamping effect, can be performed in a single operation for the two strands concerned. There is a specific opening for each strand and even in the case, say, of cables which are difficult to work or manipulate a firm and secure fixing of the cable in the connector can be achieved.
It is particularly favourable in this invention that the connector can be of small dimensions only and further that it is readily possible to avoid sharp edged surfaces at the exterior of the connector. Consequently the use of these connectors will change the outer aspect of a net structure only very little and the danger of injury or damage is small, which is of importance particularly in the case of a climbing net.
Where it is required to connect two crossing strands, i.e. lengths of cable, the openings referred to can be arranged in cruciform fashion relatively to one another at the two sides of the connector. In this case it may be of advantage to adopt an arrangement in which the two aforesaid openings merge partly into one another which means that in the finished joint the two cable lengths will deform one another to a partial extent. This further reduces the external dimensions.
The same clamped connection of this invention can also be used to join strands which run parallel to one another, and there is no problem in cases where the strands are run at an acute angle to one another at the point of intersection.
The invention may not only be used for climbing nets or the like, but in nets for other purposes, for example loading nets, nets for building construction, and so on. It can also be used in other strandconnecting situations.
These features of the invention are disclosed in the ensuing description of a number of embodiments of the invention which have been diagrammatically illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In these drawings:
FIG. 1 is a perspective illustration of the clamping connection of two crossing cables by means of a connector according to the invention,
FIG. 2 is a cross section through the arrangement illustrated in FIG. 1, taken on the line II--II,
FIGS. 3-6 are respectively two front views, a plan view and a bottom view of the connector illustrated in FIGS. 1 and 2, prior to use,
FIG. 7 is a side view of a modified form of connector according to the invention, this shown in operative assembled condition,
FIG. 8 is a top plan view of the arrangement illustrated in FIG. 7,
FIGS. 9-11 are respectively two side views and a plan view of the connector illustrated in FIGS. 7 and 8, prior to use,
FIGS. 12 and 13 are respectively a plan view and side view of a further modified version of the connector of this invention, prior to use, and
FIG. 14 is a perspective view of a tool which can be used to deform the connector of the present invention.
DETAILED DESCRIPTION
The connector of this invention is preferably made of aluminium, but other materials can be used, for example steel or even a plastics material. In the latter case a heating process can be used for the deformation of the unit (see below).
The connector 1 illustrated in FIGS. 1-6 is, when assembled and operated, basically a body of rotation and its shape is derived from an embryo form which may be regarded as a double cone, namely the two cones 16 and 17 (FIGS. 3 and 4). The angle of taper of each of these conical formations is about 15°, but fluctuations between 10° and 20° are possible. This choice means a favourable relation between the outer dimensions of the finished product, on the one hand, and the deformation forces which have to be applied to produce this finished status. The double cone is provided with the openings 2 and 3, these being chosen of a depth such that their sum somewhat exceeds the full height of the finished article. This achieves the result that these openings 2 and 3 in effect penetrate into the central area and this method of construction means that the cable lengths 8 and 9 are deformed at their point of contact with the advantage that the total dimensions of the connector are somewhat reduced in the final condition. The opening 2 is defined by the walls 10 and opening 3 by walls 11. It is recommended that bevelled parts 18 are provided at the upper and lower ends of the connector workpiece which is to be deformed.
In making a clamped connection between two crossing cables one of these, for example 8, is laid in the opening 2, whilst opening 3 receives the other cable length 9. This preparatory joint is placed in a tool which can be made up of two substantially like parts, as illustrated in FIG. 14. Each of the two parts 19 and 20 of the tool has a semi-spherical recess 21 and 22 respectively and each of the walls defining these recesses 21 and 22 are provided with semi-spherical apertures 23 and 24 respectively. The crossing cable parts with the undeformed connector are introduced into the tool in such a way that for example the lower length of cable 9 is placed in the larger aperture 24 and the two parts of the tool 19 and 20 co-act in such a way that the apertures 23 and 24 always supplement one another.
When appropriate pressure is applied in the directions of arrows 25 the connector 1 is so deformed as to assume a spherical sort of shape. The walls 10 and 11 are brought together until they touch. In the completed comdition a small oppositely disposed wedge-shaped gaps 26 are left. The completed connector has only comparatively small dimensions which are more or less equal in all directions. In all cases the gripping force which is achieved is adequate.
Particularly favourable in the implementation of the invention is the fact that, as for example is illustrated in FIG. 2, the base of the deformed walls 10 and 11 is comparatively wide so that although the walls only touch after the deformation and are not welded to one another or otherwise positively connected, a powerful grip is achieved.
The pressures on which the grip depends are adapted to the cable or rope lengths which are being dealt with in appropriate cases. If wire cables are the subject of the operation it will be possible to use higher pressures than, for example, in the case of ropes of textile fibres or cables of which the outer surface is constituted by textile fibres.
Whereas FIGS. 1 to 6 illustrate an embodiment in which two crossing lengths of cable 8 and 9 are connected, FIGS. 7 to 11 illustrate a variation dealing with parallel lengths of cable 6 and 7. In this case the connector I likewise has two U-shaped openings 4 and 5 which however, see FIG. 9, are parallel to one another. With this construction it is not possible for the openings to pass mutually into one another because this would divide the connector. However, to cater for optimum deformability it is of advantage to provide a channel 14 internally of the connector. The form of the outer faces of the double cones 16 and 17 and the application of the bevelling 18 correspond to the embodiment of FIGS. 1 to 6 described above.
On account of the specifics of the constructional form of FIGS. 7 to 11 the finished connector 1 deviates in this case somewhat more from the spherical or ball shape. The dimensions are slightly greater in the plane of the two cable lengths 6 and 7 than at right angles thereto, for example. These distinctions are however minor.
It has been found that the connector of FIGS. 7 to 11 can be deformed and finished with the same tool as that used in the embodiment referred to in FIGS. 1 to 6. It is only necessary to turn the part 20 of the tool through 90° relatively to the part 19 so that the apertures 23 and the apertures 24 are brought into appropriate register with one another. In this particular instance the apertures 23 have no function and at the end of the pressing operation the tools will retain a spacing from one another.
FIGS. 12 and 13 indicate a variation of connector of FIGS. 9 to 11 in which the boundaries of the walls 12 and 13 defining the U-shaped openings 4 and 5 are bevelled at 15. This bevelling will be conserved when the clamping by the connector is complete. Such bevelling somewhat improves the motion of the cable held in the connector and avoids the danger that the boundaries of the outer walls will, if sharp-edged, cut into the cable or rope. The bevelling 15 could of course also be used for a connector in which the U-shaped openings cross, as in the case of openings 2 and 3 of the embodiment illustrated in FIGS. 1 to 6 of the drawings.
Where reference is made in connection with this invention to a spherical shape assumed by the connector after deformation this is not meant to indicate a perfect geometrical spherical shape. There are bodies of rotation of spherical type in which there are differences between the individual outer dimensions. Whilst a curved outer shape is as a rule to be preferred in the finished connector as conferring the best results, outer shapes can nevertheless be used which are composed of individual plane surfaces or surfaces which have a curvature which is shallower than a proper spherical shape.
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The subject of this invention is a connector used to connect or clamp together at least two strands, as for example at the nodes or crossings in a net. To make the connector of little bulk and obtrusiveness, while still giving a secure jointing effect, it is provided by a blank which is shaped to furnish openings or passages for reception of the crossing or adjacent strands and is deformed under pressure to enclose and grip these strands at their junction in a small coherent body of small overall dimension.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to the field of pay computer-controlled games, either games of skills or games of chance, and more particularly to the field of cashless gaming systems and methods.
[0003] 2. Description of the Related Art
[0004] Conventional cashless methods and systems typically rely on centralized accounts (player accounts, anonymous game session accounts, voucher verification accounts, smartcard reconciliation accounts) that are managed by a complex central system (i.e., controlled or coupled to a central server). Such systems require the services of highly trained professionals and the maintenance of stringent security procedures. This leads to high operational costs that are not acceptable for small to medium sized gaming operators. Centralized systems of the prior art are described in U.S. Pat. Nos. 6,280,328, 5,265,874 and 6,048,269.
[0005] What are needed, therefore, are cashless gaming methods and systems that overcome the complexity, cost and manpower of conventional gaming methods and systems.
SUMMARY OF THE INVENTION
[0006] It is, therefore, an object of this invention to offer gaming terminals and network architectures, systems and methods that overcome the complexity, cost and manpower inherent in conventional gaming terminals, network architectures, methodologies and systems.
[0007] According to embodiments of the present invention, each networked gaming terminal comprises a highly secure enclosure because of the strict regulations that are imposed in gaming jurisdictions. The compute modules thereof are carefully partitioned with multiple locking mechanisms and alarm systems. Strict procedures must be followed to access various parts and functions. Furthermore, the computer architecture and components of motherboards used in gaming machines are becoming enormously powerful and extremely reliable due to the technology advancements; they are identical to those used in computer servers that constitute complex central systems. Therefore, networked gaming terminals may offer an exceptionally secure and exceedingly powerful computing environment.
[0008] In the present invention, the gaming terminals are advantageously configured to support functions traditionally implemented by centralized systems. Gaming terminal software is adapted to support, in addition to the local terminal game session metering (including, for example, tracking of winning and available credits), the game session metering of one or a plurality of peer gaming terminals. A patron may deposit funds in cash or using any other financial instrument (including, for example, any form of electronic money) to a cashier or an automated network cashier, or alternatively a gaming terminal equipped with cash acceptors or other financial instrument acceptors. According to an embodiment of the present invention, the amount of money deposited by the patron is credited by the cashier, or gaming terminal or using a basic stateless (i.e. not managing the session context) entry terminal, into a peer gaming terminal or alternatively, the equivalent operation may be automatically performed by the automated network cashier. In the case of a gaming terminal equipped with financial instrument acceptors, the credit is entered directly into the local meters (i.e., not stored in memory prior to being transferred to the local meters of the gaming terminal). The patron may be issued an identification (ID) instrument that may be accepted by any gaming terminal in the network. Each time the patron submits his ID instrument (or is otherwise authenticated) to a new gaming terminal on the network, the new gaming terminal may broadcast a network message to request the previously used gaming terminal to transfer to the new terminal the game session meters corresponding to the ID instrument. That is, the request may be broadcast to all gaming terminals on the network and only the gaming terminal owning the requested game session meters will respond to the broadcast request. Consequently, the patron may play on any gaming terminal within the network and change gaming terminal at any time as long as his game session credit is not exhausted. The transfer of meters preferably occurs directly between the networked gaming terminals, without the intermediary of an intervening terminal or storage.
[0009] The patron may redeem his winnings or remaining credits by submitting his ID instrument to an automated cashier, to a cashier equipped with a network entry terminal or to a gaming terminal equipped with a coin dispenser or a bank note dispenser. For the payment operation, payment authorization may be obtained via the network from the last gaming terminal on which the patron last played.
[0010] For fault tolerance, each game session meter may be mirrored on one or a plurality of peer gaming terminals on the network.
[0011] It is a further object of this invention supports all forms of cashless instruments such as:
[0012] a player account whereby primary meters are the monetary credit balance associated to a patron ID;
[0013] an anonymous game session account whereby primary meters are the monetary credit balance associated to a game session ID;
[0014] a voucher verification account whereby the primary meters are the monetary value and the hash associated to the value amount and the encrypted signature printed or encoded on the voucher;
[0015] a time gaming account whereby the primary meters are the time-to-play balance and the total of the winnings associated to a patron ID or to a game session ID;
[0016] a smartcard reconciliation account whereby the primary meters are a mirrored copy of the meters managed in the secure electronic module of the smartcard.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] [0017]FIG. 1 is an overview diagram of an exemplary server-less cashless gaming system, in accordance with an embodiment of the present invention.
[0018] [0018]FIG. 2 is a view depicting an exemplary cashless game terminal in accordance with an embodiment of the present invention.
[0019] [0019]FIG. 3 is a view depicting an exemplary automated cashier in accordance with an embodiment of the present invention.
[0020] [0020]FIG. 4 is a diagram depicting a server-less cashless game session in accordance with an embodiment of the present invention.
[0021] [0021]FIG. 5 is a diagram depicting the cashless meters in accordance with an embodiment of the present invention.
[0022] [0022]FIG. 6 is a view depicting an exemplary cashier network entry terminal in accordance with an embodiment of the present invention.
[0023] [0023]FIG. 7 is a flowchart depicting the cashless meters in accordance with an embodiment of the present invention.
DESCRIPTION OF THE INVENTION
[0024] Reference will now be made in detail to the construction and operation of preferred implementations of the present invention illustrated in the accompanying drawings. The following description of the preferred implementations of the present invention is only exemplary of the invention. Indeed, the present invention is not limited to these implementations, but may be realized by other implementations.
[0025] [0025]FIG. 1 is an overview diagram of an exemplary server-less cashless gaming system, in accordance with an embodiment of the present invention. As shown therein, a server-less gaming system 100 according to an embodiment of the present invention may include a plurality of gaming terminals 104 , a cashier terminal 106 or an automated cashier 108 , all communicating via a wired and/or wireless network 102 . Wireless entry devices such as laptops 110 using 802.11 (for example), palmtops 112 using Bluetooth or 802.11 (for example), or Wireless Application Protocol (WAP) phones (for example) may advantageously be used in some premises for operators to consult and credit the game session meters. Advantageously, there is no central system (i.e., central server) controlling the gaming system 100 .
[0026] [0026]FIG. 2 illustrates an exemplary cashless gaming machine 200 that does not accept or redeem cash. It is to be understood that the gaming machine 200 is but one possible implementation of such a cashless gaming machine and that the present invention is not limited thereto. For cashless operation, the gaming terminal is equipped with means of capturing the encoded information associated with a cashless instrument submitted. The cashless instrument may be a physical portable instrument such as: a paper voucher comprising printed codes; a strong paper ticket comprising printed codes and encoded magnetic codes; a rigid ID card comprising printed codes, magnetic codes or optical codes; a secure contact or contact-less electronic ID device comprising sophisticated electronic (a smart card or a smart dongle); or alternatively, a user ID and password to be typed or spoken, or alternatively again advanced biometric features (finger print, voice recognition, face recognition). The information captured from a cashless instrument is processed in order to derive a pointer to a location containing the necessary computer data to identify and validate the cashless instrument. The information captured from a cashless instrument may contain an encrypted signature (or hash) to ensure that the information has not been maliciously modified. In fine, the cashless instrument allows to derive a valid “identifier code” that is used by the software to execute the appropriate transactions to emulate the use of real cash for the cashless instrument submitted. The cashless instrument is thus denoted “ID instrument” hereafter. The ID instrument may be capable of storing additional information when accessed by a device, or alternatively be replaced by a new one (i.e. a newly printed ticket). The gaming machine ID device(s) accepting the ID instrument submitted may include a magnetic card reader 204 , a SmartCard reader and writer 206 , a barcode reader 210 , a ticket printer 212 , a biometric reader (finger print, voice identification, head identification, etc.), a touch-screen 202 , keyboard or keypad to enable players to enter a PIN (Personal Identification Number). The gaming machine identification device(s) may further include an ID token reader to read other forms of advanced ID devices such as ID buttons, ID key-chains (such as disclosed, for example in commonly assigned US design patent entitled “Personal Communicator and Secure ID Device” patent number D441,765 issued on May 8, 2001) as well as secure communication means for securely communicating with, for example, personal wallets, hand held computers or computer wrist-watch via infra red, magnetic field, capacitive charges or RF (Bluetooth, IEEE 802.11, etc.) for player identification purposes. A printer 212 may print bar-coded tickets 214 that can be read by a barcode reader 210 .
[0027] [0027]FIG. 6 illustrates an example of a networked cashier terminal 600 , according to an embodiment of the present invention. The terminal may include a computer 602 connected via wired or wireless link 603 to the network 102 with the gaming machines 104 and a ticket printer 604 . The ticket printer 604 may include an integrated printer for printing tickets or receipts 606 that include a human and/or machine readable code imprinted thereon and code reader 608 for reading the code(s) imprinted on the ticket 606 . The cashier terminal may also include, for example, a magnetic card reader 610 , a SmartCard reader 612 , a biometric reader 614 (such as a fingerprint reader, for example), a display 620 and input devices such as a keyboard 618 and/or a mouse 616 . The cashier terminal may be controlled by an operating system capable of secure network communication such as Microsoft Windows, embedded XP or Linux, for example.
[0028] [0028]FIG. 3 illustrates an embodiment of an automated cashier 300 , which dispenses with the need for a human cashier. The automated cashier 300 may include an internal computer connected to the network 102 with the gaming terminals 104 , a coin acceptor 322 , a note acceptor 320 , a coin dispenser/hopper 318 , a SmartCard or magnetic card dispenser 304 , a note dispenser 314 , a ticket printer 310 for printing a ticket 312 , a magnetic card reader 302 , a SmartCard reader/writer 306 , a barcode reader 308 , display with touch-screen 326 , a keypad 324 , a video camera 328 and/or a UL 291 certified cash safe 316 , for example. The UL 291 certified cash safe 316 prevents or deters robbery of the cash stored inside the automated cashier 300 . The automated cashier 300 may further include biometric ID readers, ID token readers to read other forms of advanced ID devices such as ID buttons, ID key-chains, etc., as well as secure communications means for communicating with personal wallets, hand held PCs or computer wristwatch via infrared, magnetic field, capacitive charges or RF (Bluetooth, IEEE 802.11, etc.) for identification purposes.
[0029] According to one embodiment of the present invention, the gaming terminals (GT) 104 are advantageously configured to support functions traditionally implemented by central systems. FIG. 4 illustrates an embodiment of a server-less cashless gaming session according to the present invention. A patron 401 initially interacts with a cashier 402 to establish a cashless session 407 through to 412 . The patron 401 initializes a cashless session 408 by handing over an amount of money 407 (in whatever form) to the cashier 402 . The cashier 402 initializes the cashless meters 410 located on a predetermined gaming terminal 404 by issuing a credit meters transaction 409 using a cashier terminal 600 . The gaming terminal 404 executes a process 410 to initialize in persistent storage the cashless meters associated with this cashless session. The gaming terminal 404 may then return a session ID 411 for later access and retrieval. The cashier 402 may complete the cashless session 408 by providing the patron 401 with an ID instrument 412 corresponding to session ID 411 . The ID instrument 412 may be or include a printed ticket with text and/or encoded barcode, a printed ticket with text and/or embedded encoded magnetic strip (such as a metro ticket, for example), a magnetic ID card, a smart ID card, fingerprint recognition, voice recognition, face recognition, palm recognition (or any biometric recognition), ID buttons, ID key-chains, a personal electronic wallet, a secure handheld Computer, a secure mobile phone a secure computer wrist watch, a bar-coded ticket, a bar-coded voucher or any imaginable way to associate identification means with a physical or electronic media. A PIN number may also be given for challenging the ID instrument. The identification of the cashless session may be entirely anonymous or alternatively, may be associated with the patron's identity or membership in some group. In the later case, necessary personal identification data may be captured by the cashier when money is deposited 407 and are submitted together with the credit meters 409 for persistent storage in the gaming terminal 404 during the process 410 .
[0030] The exact same cashless session 407 through 412 may be performed by making use of the automated cashier 300 instead of the cashier terminal 600 wherein the role of the cashier 402 is replaced by an automated program executed in the automated cashier. Suitable peripherals may be attached to the automated cashier 300 to allow for the deposit of funds, capture of information and dispensing of ID instruments.
[0031] The start 413 of a cashless game session 414 may be identified by the patron 401 receiving the ID instrument 412 . The end 436 of the cashless game session 414 may be identified by the patron 401 redeeming the credit balance of money 435 associated with his ID instrument 412 , or when the credit associated with his ID is exhausted (null).
[0032] The patron 401 (who forms no part of the present invention and whose actions are only described herein to illustrate aspects of the present invention), subsequent to receiving an ID instrument 412 , may execute a certain number of cashless operations associated with his ID instrument. The patron may choose any gaming terminal 403 , 404 , 405 or 406 to play on. In the illustration of FIG. 4, the patron first chooses the gaming terminal 403 and submits his ID instrument 415 to the gaming terminal 403 . If the gaming terminal 403 does not have ownership of the cashless meters associated with the ID instrument submitted, it may immediately broadcast on the network 102 a request to acquire the cashless meters associated with the patron's ID instrument. All the gaming terminals on the network 102 intercept the broadcast. The gaming terminal 404 having ownership of the cashless meters initiates at 418 a transfer procedure 419 to transfer ownership and full content of the cashless meters associated with the ID 420 to the gaming terminal 403 . Upon receiving ownership and content of the cashless meters, gaming terminal 403 initializes its local game meters with the value of the cashless meters received and enters a gaming session 421 wherein the patron may play continuously until credit is exhausted or until the cash-out signal 422 is activated. Any winning is added to the patron's credit balance.
[0033] When the cash-out signal 422 is activated by the patron, the player may use the remaining of his or her credit to play on another gaming terminal or redeem the credit for cash. A ticket showing the credit remaining may be printed if a printing device is available on gaming terminal 403 . In the illustration of FIG. 4, patron 401 chooses to play on gaming terminal 406 and submits his ID instrument 423 to the gaming terminal 406 . Gaming terminal 406 does not have ownership of the cashless meters associated with the ID instrument submitted. Therefore, it may immediately broadcast on the network a request to acquire the cashless meters associated with the ID instrument. All the gaming terminals on the network intercept the broadcast. The gaming terminal 403 having ownership of the cashless meters initiates a transfer procedure 426 to transfer ownership and full content of the cashless meters associated with the ID 427 to the gaming terminal 406 . The gaming terminal 403 may deny the transfer of the meters if credit is exhausted or already paid, thus preventing the patron from playing on gaming terminal 406 . Upon receiving ownership and content of the cashless meters, gaming terminal 406 initializes its local game meters with the value of the cashless meters received and enters a gaming session 428 wherein the patron may play continuously until credit is exhausted or until the cash-out signal 429 is activated. Any winning is added to the credit balance.
[0034] When the cash-out signal 429 is activated, the player may use any remaining credit to play on another gaming terminal or may redeem the credit for cash (or for credit on another payment instrument or account). A ticket showing the credit remaining may be printed if a printing device is available on gaming terminal 406 . In the illustration of FIG. 4, patron 401 chooses to redeem his credit for cash. The patron submits his ID instrument at 430 to the cashier 402 who initiates a redeem process 431 that may immediately broadcast on the network a request to acquire the cashless meters associated with the ID instrument submitted 430 . All the gaming terminals on the network intercept the broadcast. The gaming terminal 406 having ownership of the cashless meters authorizes payment by initiating a closure process 433 to terminate ownership of the cashless meters and forward the credit balance amount to pay at 434 to the cashier terminal 402 . The gaming terminal 406 may deny payment if credit is exhausted. Upon receiving the authorization from gaming terminal 406 , the cashier 402 then hands over the associated money 435 to the patron 401 . The cashless game session associated with the ID instrument 414 terminates 436 when the patron receives his money 435 . It is understood that the actions of the cashier described herein may be readily automated.
[0035] In another embodiment of the present invention, the patron may request partial payment of the credit available. In that case, the gaming terminal 406 having ownership of the cashless meters associated with the patron or the patron's ID instrument authorizes payment and initiates an update process instead of a closure process 433 in order to reflect the amount of payment made. Subsequently, the patron may continue to play on any gaming terminal or later redeem his credits at a cashier using his ID instrument.
[0036] For clarity of illustration, the server-less gaming session 400 of FIG. 4 shows only four game terminals and one cashier operating over a peer-to-peer platform. This is an ideal scenario for small game operators. It should be apparent to those acquainted with modem network architectures that the peer-to-peer architecture disclosed herein is highly scalable and robust and that the scenario 400 can be extended to a large gaming estate comprising tens of thousands of gaming terminals and hundreds of cashier terminals or automated cashiers. Moreover, peer-to-peer mechanisms may be provided by modem operating systems such as Microsoft .NET and secure network protocols may be automatically activated by setting the appropriate security policy such as Internet Protocol Security (IPSec) or Secure Socket Layer (SSL), for example. Furthermore, cashier terminals 600 and automated cashier 300 only require simple “stateless”.NET client applications or web browser sessions for interacting with the gaming terminals 104 . The term “stateless” denotes that the software that executes in the cashier terminal 600 and in the automated cashier 300 is not responsible for managing and recording the game session implicit state or context. The context of a software session is the ordered sequence of properties of the software objects that defines it at a particular instant in time. The context (or implicit state) of a cashless gaming session is controlled and recorded by the gaming terminal that owns the associated cashless session meters. The context of a cashless gaming session includes the meters. The gaming terminal may advantageously store the game session context that includes the meters in a non-volatile memory for fault-tolerance.
[0037] The method and a server-less gaming session 400 of the present invention and illustrated on FIG. 4 is further illustrated in a flowchart 700 of FIG. 7. As shown, a patron remits funds to any of the cashiers at 702 , whereupon the cashier initializes meters on a predetermined gaming terminal at 704 and the cashier dispenses and ID instrument to the patron at 706 . At 708 , the patron may choose to play on a gaming terminal at 710 or go to the cashier 734 to redeem his credit, such as shown at 732 .
[0038] The patron submits his ID instrument at 712 to the selected gaming terminal that requests transfer of meters associated with the ID instrument from a previous gaming terminal 714 (the gaming terminal on which the patron last played), or alternatively in the case whereby the patron has just remitted funds to a cashier, from the gaming terminal on which the cashier has initialized the meters on. The previous gaming terminal may deny transfer of meters if the credit is exhausted or already paid, thus preventing the patron from playing a game.
[0039] Once the transfer of meters from a previous gaming terminal is successfully completed, the patron may repetitively play a game at 716 as long as his credit is not exhausted as shown at 718 or the cash-out signal has not been activated 722 , 726 . In case credit is exhausted 728 , the patron can no longer play and the cashless game session terminates at 730 .
[0040] After activating the cash-out signal 722 , 724 , the patron may choose another gaming terminal 708 and proceed as described above. If the patron no longer wishes to play 732 , he may go to a cashier 734 to redeem his credit by submitting his ID instrument 736 . The cashier may use his network entry terminal to obtain payment authorization from the previous gaming terminal 738 . If authorization is given, the credit amount available in the meters of the previous gaming machine may be paid by the cashier 740 , and the meters at the previous gaming terminal may be updated to reflect the payment.
[0041] Traditionally and in compliance with gaming jurisdictions, gaming terminals may contain a set of highly secure persistent meters comprising essentially the patron's credit balance, the meters associated with a variety of events such as coins inserted and coins given out for a particular game, and an audit log of events for later examination if required. The operation for updating the meters in accordance with the game session activity is commonly referred as metering. Metering also infers that the necessary storage and access means to the meters are available. Applying modern object oriented programming and persistent data storage techniques such as structured access to non-volatile memory, the meters may be defined as a class that is dynamically instantiated at run time. It may be clear to those acquainted with object programming that a multitude of instantiations of the meters class may be obtained, the only limitation being the memory available. Memory being plentiful on a typical computer unit controlling a gaming terminal, a substantial number of instantiations of the meters class may be obtained.
[0042] [0042]FIG. 5 illustrates the instantiation of a number of cashless meters 500 that may be obtained on a gaming terminal 502 . The gaming terminal 502 has taken ownership of the cashless meters associated with each of the patrons' submitted ID instrument for ID(x), ID(y) through ID(z) and the gaming activity in process on gaming terminal 502 is reflected in the current session cashless meters 504 . The credit balance displayed to the patron currently playing corresponds to the credit balance meter 506 ; the other meters 508 and the audit log 510 may be reserved for use by the game operator. The cashless meters may be frozen when the patron activates the cash-out signal.
[0043] The other meters 512 , 514 and 516 are associated with gaming sessions played previously on the gaming terminal 502 and are frozen. Alternatively, any of the meters 512 , 514 or 516 may be associated with a new cashless session initiated by the cashier when the patron deposit funds as explained relative to steps 407 to 412 . Gaming terminal 502 retain ownership of the frozen meters until ownership is requested by another gaming terminal. If the credit remaining on these meters is exhausted, transfer of ownership to another gaming terminal is denied. If a redeem operation is requested by the cashier terminal or the automated cashier while some credit is available, the gaming terminal 502 authorizes payment, closes the meters and retains ownership of the closed meters. The closed meters may be erased at a later time in order to recover storage space in accordance with the gaming operator's rules for flushing old data.
[0044] The peer-to-peer metering method object of the present invention is suitable for supporting all forms of cashless instruments such as:
[0045] a player account;
[0046] an anonymous game session account;
[0047] a voucher verification account;
[0048] a time gaming account;
[0049] a smartcard reconciliation account.
[0050] A cashless player account is identified by a unique identifier key assigned to a patron that points to a set of records stored in computer memory containing the patron's personal details and the state of the cashless session. The records may be queried and updated by authorized software using the key that may be derived from the ID instrument submitted. The state of the cashless session comprises essentially the balance of monetary credit available to the patron (the primary meters) and some auxiliary attributes (secondary meters) reflecting the games played, the time stamping of various operations, a flag indicating if the meters are owned by the gaming terminal hosting the meters and a flag indicating if available credits have already been paid.
[0051] An anonymous game session account is identified by a unique identifier key assigned to a game session that points to a set of records stored in computer memory containing the state of the cashless session. The records may be queried and updated by authorized software using the key that may be derived from the ID instrument submitted. The state of the cashless session comprises essentially (the primary meters) the balance of monetary credit available to the anonymous older of the ID instrument and some auxiliary attributes (secondary meters) reflecting the games played, the time stamping of various operations, a flag indicating if the meters are owned by the gaming terminal hosting the meters and a flag indicating if available credits have already been paid.
[0052] A voucher verification account is identified by a unique identifier key assigned to a voucher that points to a set of records stored in computer memory containing the state of the cashless session. The records may be queried and updated by authorized software using the key that may be derived from the voucher submitted. The state of the cashless session comprises essentially (the primary meters) the balance of monetary credit available to the holder of the voucher and verification data, and some auxiliary attributes (secondary meters) reflecting the games played, the time stamping of various operations, a flag indicating if the meters are owned by the gaming terminal hosting the meters, and a flag indicating if available credits have already been paid. In the case of a cash-out at the gaming terminal or alternatively when funds are remitted to a human cashier or an automated cashier, a voucher comprising clear text and machine-readable code representing the monetary value of the credit available and some verification data is dispensed. The clear text may indicate the value of the credit available, or simply said for the holder, “the value of voucher”. In the case of a cash-in at the gaming terminal or alternatively when requesting the redeem of credits to a human cashier or an automated cashier, a voucher comprising clear text and machine-readable code representing the monetary value of the credit available and some verification data is read. The unique identifier key is derived from the verification data upon reading the clear text and/or the machine-readable code. The associated records are then queried in order to authenticate the value of the voucher by comparing the verification data contained in the records with the verification data read from the voucher. It should be apparent to those acquainted with secure transactional techniques that the unique identifier key, or alternatively the verification data, may be a hash or an encrypted signature of all or portion of the clear text and/or the machine-readable code.
[0053] A time gaming account may be associated to a patron or be anonymous.
[0054] A time gaming player account is identified by a unique identifier key assigned to a patron that points to a set of records stored in computer memory containing the patron's personal details and the state of the cashless session. The records may be queried and updated by authorized software using the key that may be derived from the ID instrument submitted. The state of the cashless session comprises essentially (the primary meters) the balance of time-to-play and the total of winnings available to the patron, and some auxiliary attributes (secondary meters) reflecting the games played, the time stamping of various operations, a flag indicating if the meters are owned by the gaming terminal hosting the meters and a flag indicating if available credits have already been redeeming.
[0055] An anonymous time gaming account is identified by a unique identifier key assigned to a gaming session that points to a set of records stored in computer memory containing the state of the cashless session. The records may be queried and updated by authorized software using the key that may be derived from the ID instrument submitted. The state of the cashless session comprises essentially (the primary meters) the balance of time-to-play and the total of winnings available to the anonymous holder of the ID instrument, and some auxiliary attributes (secondary meters) reflecting the games played, the time stamping of various operations, a flag indicating if the meters are owned by the gaming terminal hosting the meters and a flag indicating if available credits have already been redeeming.
[0056] A smartcard reconciliation account is identified by a unique identifier key assigned to a smartcard that points to a set of records stored in computer memory. The records therefor are a “slave” mirrored copy of same records containing the state of the cashless session that are maintained in the electronic circuits of the smartcard. The smartcard maintains the “master” copy of the records. The slaved mirrored records may be queried but not updated by authorized software using the key that may be derived from the smartcard submitted. The state of the cashless session comprises essentially the balance of credit available to the holder of the smartcard (the primary meters) and some auxiliary attributes (secondary meters) reflecting the games played, the time stamping of various operations, a flag indicating if the meters are owned by the gaming terminal hosting the meters and a flag indicating if available credits have already been paid. The slaved mirrored records are used to reconcile accounting when the smartcard is used in order to detect possible forgery. Alternatively, the slaved mirrored records are used as a backup repository to pay the holder of the smartcard in case of the failure of the smartcard. When used for backup, the “slave” records may be updated by authorized software using the key that may be derived from the smartcard submitted (embossed code for example).
[0057] The ID instrument used to derive the unique identifier key may be submitted in a variety of ways such as typing a user ID and password, keying-in a code on a keypad, presenting a bar-coded voucher, an encoded card, a secure electronic ID device or recognizing biometric features.
[0058] The unique identifier keys are commonly called GUI or global unique identifier.
[0059] Fault tolerance may be achieved by replicating (mirroring) cashless meters owned by a given gaming terminal to a predetermined number of other peer gaming terminals. The gaming terminals holding replicated cashless meters are second-level owners that may be solicited in case the primary owner does not respond to the initial transfer request, whether the request is a direct one to an identified gaming terminal or broadcast to all gaming terminals on the network. For example, in case gaming terminal 403 does not obtain any reply subsequent to its transfer request broadcast 417 after a time-out, a new broadcast message explicitly soliciting secondary owners may be sent on the network. Gaming machine 403 would then accept the transfer of cashless meters from a responding secondary owner.
[0060] In another embodiment of the present invention, the gaming terminal may be able to encode information on the ID instrument submitted by the patron. The identification of the gaming machine used by the patron may advantageously be encoded on the ID instrument such that the next used gaming terminal knows immediately upon reading the ID instrument the identity of the previously used gaming terminal. Consequently, the next used terminal may establish network communication with the previously used gaming terminal without having to rely on network broadcasting techniques to find out which of the connected gaming terminals is the last used gaming terminal, thus reducing the time to start transferring the meters and the overall network traffic. In case the last gaming terminal is not contactable, a network broadcast to find a secondary owner of the meters may be initiated.
CONCLUSIONS
[0061] The invention offers a simple distributed peer-to-peer metering of cashless game sessions that is secure, robust, scalable and that requires no central system.
[0062] All the sensitive operations are carried out by the secure software (preferably certified by a recognized test laboratory) that executes in each gaming machine. All the access points to any of the gaming terminals such as the cashier terminal or the automated cashier require only basic stateless client applications operating over a secure network protocol such as IPSec or SSL. Moreover, sophisticated relational databases are not required. Wireless laptops or palmtops may be advantageously used as entry or control terminals.
[0063] The invention supports all forms of cashless instruments such as:
[0064] a player account whereby primary meters are the monetary credit balance associated to a patron ID;
[0065] an anonymous game session account whereby primary meters are the monetary credit balance associated to a game session ID;
[0066] a voucher verification account whereby the primary meters are the monetary value and the hash associated to the value amount and the encrypted signature printed or encoded on the voucher;
[0067] a time gaming account whereby the primary meters are the time-to-play balance and the total of the winnings associated to a patron ID or to a game session ID;
[0068] a smartcard reconciliation account whereby the primary meters are a mirrored copy of the meters managed in the secure electronic module of the smartcard.
[0069] The invention may be advantageously deployed for small to medium size game operators.
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Methods and systems that enable cashless gaming dispense with the need to set up and operate a complex centrally controlled system or dispense with the need to distribute expensive smart cards. The patrons' gaming session meters (including, for example, a measure of winning and/or available credit) are distributed amongst an estate of peer networked gaming terminals.
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BACKGROUND OF THE INVENTION
This invention relates to exploding boxes, and more particularly to exploding boxes which are used to startle unsuspecting persons who open such boxes.
Exploding boxes or tubes have been produced in the past for the purpose of startling or surprising the user. For example, a simple jack-in-the-box is a form of exploding box, where a crank mechanism releases a lid allowing a spring- loaded puppet surprisingly to emerge from the box. A difficulty with the common jack-in-the-box, however, is that the crank mechanism makes the nature of the box recognizable and gives away much of the surprise.
Another type of exploding box is a cylindrical tube with a screwed on lid having an expandable, spring-loaded, cylindrical member located inside. When the lid is screwed off, the spring-loaded inner member jumps out surprising the person removing the lid. A difficulty with this type of device is that it is so well known that it is very difficult to startle anyone who is handed the device to open.
There are other types of devices available that spring open to surprise or startle the user. One example of such devices is shown in J. V. Zaruba U.S. Pat. No. 4,662,633 issued for an exploding box which is decorated to resemble a washing machine. When articles are forced into the box from the top, they push downwards against a bottom. When the bottom is pushed down sufficiently, hinged sides of the box are concurrently lowered relative to a downturned flange on the top of the box which holds them in an upright position. When the sides are sufficiently lowered, they are released from the flange on the top of the box. The sides spring outwards spewing out the contents of the box.
Another such device is shown in U.K. patent No. 2,012,601 issued to A. E. Goldfarb et al which shows a game having a pyramid which has hinged sides that are held in an upright position by a top. The sides are pivotally attached to the bottom of the pyramid. A balloon located within the pyramid is inflated by a pump. At a threshold pressure the top lifts off and the sides of the pyramid spring outward. The top then falls. The motion is limited to the pivotal outward swing of the sides and the toppling of the top.
The problem with the prior art devices shown in Zaruba and Goldfarb is that the sudden movement is too limited to startle most unsuspecting users.
SUMMARY OF THE INVENTION
The present invention is a box with hinged sides and a spring-loaded false bottom that urges the sides to open. A removable lid holds the sides together. Upon removal of the lid, the sides pop open and the false bottom springs up ejecting any contents of the box.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view of a closed box;
FIG. 2 is a cross-sectional view of the closed box taken along lines 2--2 of FIG. 1;
FIG. 3 is a cross-sectional view similar to FIG. 2 but showing the box in a partially open position;
FIG. 4 is a sectional view similar to FIG. 3 but showing the box in a fully open position;
FIG. 5 is a perspective view of an alternative embodiment of a box in an open position;
FIG. 6 is a cross-sectional view similar to FIG. 2 but showing some modifications to the preferred embodiment; and
FIG. 7 is a perspective view of a partially opened box having grooved sides and its lid removed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, an exploding box 2 is shown in a closed position in FIG. 1. The box has sides 20, and a removable lid 22. FIG. 2 is a cross-sectional view of the box taken along lines 2--2 of FIG. 1. Sides 20 have upper end portions 26, intermediate sidewall portions 28 and lower end portions 30. A hinge 32 is located between each lower end portion 30 and the intermediate sidewall portion 28. Hinge 32 is represented by a dashed fold line 34 in FIG. 1 and indicates where the sides fold outwardly. It was found to be desirable to situate the hinge 32 on the sides 20 of the box about 1/2 to 11/2 inches, or most preferably 3/4 inch, above a bottom member 40. This arrangement facilitates the release of the sides 20 and a false bottom 38 when the box is grasped by the lower end portions 30. The lid 22 has a downturned flange 24 which is adjacent to the outside of the upper end portions 26 of the sides 20 of the box. When the lid 22 is on the box 2 as seen in FIG. 1, the downturned flange 24 on the lid 22 prevents the sides 20 from hingeably folding outwardly along fold lines 34.
A compressed spring 36 is disposed between false bottom 38 and bottom member 40. The bottom member 40 is affixed to the lower end portions 30 of sides 20 of the box 2. The spring 36 pushes upwardly against false bottom 38. The false bottom 38 is held down by abutments 42 which project inwardly from the intermediate sidewalls 28 of the box. Reinforcement plates 44 affix the ends of the spring to the false bottom 38 and the bottom member 40.
FIG. 3 is a cross-sectional view of the box with the lid 22 removed. When the lid 22 is removed the false bottom 38 pushing upwardly forces the sides 20 to fold outwardly at the hinges 32, disposed between the lower end portions 30 and the intermediate sidewalls 28. After the sides have folded outwardly the abutments 42 no longer hold the false bottom 38 down against the force of the spring 36. The spring 36 then expands lifting the false bottom 38.
FIG. 4 shows the box 2 in a fully open position.
FIG. 5 is a perspective view of an embodiment of the box having the hinge 32 disposed between the lower end portions 30 and the bottom member 40 of the box 2.
FIG. 6 is a cross-section of a box having a sign such as a greeting card 46 affixed to the false bottom 38 of the box. The card 46 may be selected so as to have an appropriate greeting for the occasion e.g. Happy Birthday. The card will spring forth, opening when the lid of the box is removed. An abutment 42 is shown on one side 20 of the box 2 engaging the false bottom 38. An alternative latch means in the form of a horizontal groove 48 is shown on the other side of the box 2 engaging the false bottom 38.
FIG. 7 is a perspective view of a box having groove 48 latch means. The grooves 48 are adapted to engage the false bottom 38 of the box The grooves 48 are shown on the upright sides of the box engaging the false bottom 38. The grooves 48 are most clearly shown on the open sides 20 of the box 2. A hinge 32 is shown between a side 20 of the box 2 and the bottom member 40.
In preferred embodiments, the exterior of the box 2 is decoratively printed or covered with decorative paper. The sides may be made of cardboard. Hinges 32 may be thinner paper or simply be decorative paper spanning between the cardboard bottom member 40 and sides 20 which fold outwards. Alternatively, box 2 may be made of a suitable plastic material, with hinges 32 being formed by reducing the wall thickness, or by any other suitable means.
Having described the drawings of the box, it can be appreciated that the exploding box will spring forth any contents which are placed on the false bottom 38 above the compressed spring. It is suggested that confetti, foam chips, or a greeting card secured to the false bottom 38 with an accordion type connector might be used in the box. The greeting or item to be sprung forth would be selected to suit the occasion and the recipient. A ribbon might be used to secure a small gift to the false bottom 38 of the box. For safety reasons, it is important not to place any hard items in the box which might injure a person opening the box.
It is suggested that the box might surprise the same recipient more than once if it were enclosed within a box containing a gift. In this case, the bottom of the exploding box would be affixed to the bottom of the gift box, and the cover of the exploding box would be affixed or tied to the cover of the gift box. This would result in the exploding box springing forth its contents when the recipient of the gift lifted its cover.
It will also be appreciated that any number of sides 20 may be employed, as long as there are at least two sides disposed in a manner such that false bottom 38 is held in position when said sides are retained in an upright configuration.
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An exploding box is disclosed having upright sides which are provided with horizontal ribs or grooves which lock a false box bottom in position while the sides are maintained in an upright position by a top cover or lid. The false bottom is biased upwards by a compressed spring. When the top cover is removed, the upright sides of the box fold outwards, releasing the false bottom. The false bottom then springs upwards, springing forth any contents in the box.
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FIELD OF THE INVENTION
The present invention describes a new mattress cover sheet with high bacteriological isolation power and ideal biocompatibility characteristics.
PRIOR ART
The mattress cover sheets have the function of isolating the mattress from the human body. Close contact between the human body and the mattress is in fact generally not advisable: the mattress is normally an excellent breeding ground for bacteria and mites due to the microclimate created during use (temperature, humidity, prolonged time). The mattress contains dusty material (deriving from the natural wool or erosion of the foam rubber) which can pass through the surface of the mattress and irritate the skin. Furthermore, as time passes, the surface layers of the mattress are subject to deterioration/contamination with bacteria and parasites; the deteriorated/contaminated surface can in its turn cause phenomena of skin irritation/allergy; in particular the passage of bacteria and parasites from the mattress towards the person should be avoided.
The role of the mattress cover is therefore that of providing a barrier between the mattress and the person, limiting deterioration of the mattress and above all preventing the passage of irritating substances, bacteria or parasites from the mattress to the person; at the same time, however, the sheet must allow the skin to breathe otherwise the above irritation phenomena can re-occur.
The mattress covers produced so far only partly satisfy the above requirements: for example, the barrier effect is obtained by considerably increasing the thickness of the sheet or adding plastic materials, and this considerably limits breathability. In some cases fabrics impregnated with antibacterial materials have been used but in this case the antibacterial product can be easily released, creating problems of skin toxicity and loss of the barrier effect of the sheet.
There is therefore a need for mattress cover sheets free from the above limitations which are able, in particular, to provide an effective barrier and at the same time are biocompatible and comfortable for the user.
SUMMARY OF THE INVENTION
The present invention describes a new mattress cover sheet with barrier effect against bacteria and parasites, comprising a spunlace fibre based fabric. The spunlace fabric mattress cover can be produced in a structure with one or more layers and can contain antibacterial substances. The sheet subject of the invention provides an effective barrier between the person and the mattress, in particular avoiding the transfer of pollutants from the mattress to the person and at the same time protecting the hygiene of the mattress itself.
DESCRIPTION OF THE FIGURES
FIGS. 1–3 : Assessment of the antibacterial barrier of the mattress cover sheet against Staphylococcus aureus ATCC 6538.
DETAILED DESCRIPTION OF THE INVENTION
The present invention concerns a mattress cover sheet comprising a spunlace fibre based fabric.
Spunlace fabrics are non-woven fabrics, the fibres of which are mechanically interconnected; the interconnection is obtained by entangling the fibres by means of fine jets of water.
Spunlace fibres are formed, in particular, as follows: the fibres to be processed are mixed in the required proportions with the addition of additives if necessary to improve workability; the fibres are then carded, i.e. rendered uniform in a web which is calendered if necessary; the web is then entangled as above to give it the physical and mechanical characteristics of a non-woven fabric: in this phase the fibres are linked (entangled) by very fine powerful jets of water, felting the product. During these treatments, the product is supported by belts and cylinders and is crossed by jets of water; finally, the product is dried and calendered if necessary. The most common application of the spunlace technology is in the preparation of absorbent materials for cleaning and/or sanitisation of surfaces (for example kitchen worktop cleaning cloths) and for wipes (personal hygiene, make-up . . . ). The present invention concerns a spunlace fabric based mattress cover sheet. The spunlace fabric used for the purposes of the invention has a weight/surface ratio of at least 20 g/m 2 ; preferably it is between 30 g/m 2 and 80 g/m 2 , for example 50 g/m 2 . The use of this weight/surface ratio range provides an excellent ratio between barrier effect and lightness/breathability of the fabric.
The fibres of the spunlace fabric used in the present invention are preferably chosen from polyester, viscose (artificial silk), polypropylene, polyamide, cotton or cellulose pulp fibres. It is possible to use one single type of fibre or fibres of different types combined. The viscose/polyester combination is preferred in particular: in it the viscose performs a mainly absorbent function, while the polyester increases the fabric strength; in these combinations, the viscose constitutes 50%–80% in weight, with the polyester constituting the remaining weight.
The dimensions of the fibres are generally between 0.9 and 3.3 dtex; the dtex, an indirect unit of measurement of the fibre section, indicates the weight in grams of 10,000 m of yarn.
In the sheet subject of the invention, the barrier effect can be further increased by applying one or more of the following techniques:
(i) production of a multilayer fabric, at least one layer of which consists of spunlace fabric; (ii) addition of antibacterial substances incorporated in the fibre; (iii) addition of antibacterial substances impregnated in the fabric.
Solution (i) provides for the formation of a multilayer structure. For example, a three-layer (sandwich) structure can be obtained in which the two outer layers are made of synthetic fibre, e.g. polyester, and the inner layer is made of an absorbent material, e.g. cellulose pulp. The adjacent layers can be joined by means of known systems including the spunlace process. It is therefore possible to entangle, as described above, a structure consisting of different overlapping layers of fibres, obtaining in this case a multilayer spunlace fabric. The outer layers can have a weight/surface ratio of 10–15 g/m 2 and the inner layer 20–40 g/m 2 .
In solution (ii) the sheet contains antibacterial substances incorporated in the innermost structure of the fibre. The antibacterial substance is incorporated during the synthetic fibre extrusion phase, i.e. during the process of formation of the fibre itself. In general any antibacterial substances compatible with the process of incorporation and non-toxic to humans can be used; in the present invention the term “antibacterial” also comprises disinfectant, parasiticidal and insecticidal substances. Preferred antibacterial substances are: zeolite with silver, copper or zinc base, or organic additives such as Triclosan. These substances are characterised by a high effectiveness in preventing the formation of bacterial colonies and at the same time high compatibility and non-toxicity for humans.
In solution (iii) the sheet comprises antibacterial substances which are added to the fabric by means of an impregnation process.
The techniques described in points (i)–(iii) can be used alternatively or combined: for example, it is possible to produce a three-layer fabric impregnated with antibacterial substances, or the fibres of which contain the incorporated antibacterial substance.
The mattress cover sheet subject of the present invention is of the dimensions necessary to cover a mattress or a pair of mattresses (for example 1.5×2.5 meters or 2.5×3 meters) and is preferably provided with common means of attachment to the mattress, such as buckles, belts or hooks, or can be designed to wrap around and below the side edges of the mattress. The sheet can also be produced in a bag version, thus covering the entire mattress surface.
A further aim of the invention is a process for producing a mattress cover sheet characterised by the use of a spunlace fabric among the materials making up the sheet. The spunlace fabric can be in a ready-to-use form or can be produced extemporarily by entangling a layer of fibre, as described above. In the latter case, reference is made to the known processes for the formation of spunlace fabric such as those illustrated in the previous description of the known technique.
For production of the sheet according to one of the preferred solutions (i)–(iii) described above, the process will include respectively:
In case (i): the production of a multilayer fabric.
To produce the multilayer fabric, the layers of fibre are overlapped in the required order and directly subjected to the spunlace process, or it is possible to perform an initial calendering phase and then proceed with the spunlace process which completes the interconnection between the fibres. In any case, at the end of the process a coherent product is obtained in which the different layers are firmly interconnected. The pre-treatment by means of calendering is particularly effective in increasing the barrier effect.
In case (ii): the use of fibres containing antibacterial substances directly incorporated in the fibre.
The process of incorporation of additives in the synthetic fibres is known: it consists in adding the additive to the mixture which is fed into the extruder and which constitutes the fibre. This process produces a strong chemical-physical link between the molecules of the additive (in this case antibacterial additive) and polymer, obtaining effective fixing of the product which cannot be released to the environment.
In case (iii): the addition of antibacterial substances by means of impregnation of the fabric.
In this case the antibacterial substance is sprayed onto the fabric already formed, or during the phase immediately prior to the spunlace process or during the latter. For impregnation, a “foulard” application process is preferably used which permits uniform absorption of the product.
This process involves a first phase where the product is submerged in a solution contained in a tank and its physical structure is completely saturated with said solution. The second phase involves passage of the article between two opposed cylinders which have a squeezing effect; this operation regulates the amount of solution to be left on the product.
In all the cases described, the spunlace fabric, damp following the spunlace process and/or spraying with the antibacterial substances, undergoes a final drying process. Drying can be performed for example by tensioning the fabric on cylinders inside drying ovens: in this case a stretching effect is obtained which physically completes protection of the sheet in addition, obviously, to evaporating the water present in the product.
Finally, the fabric is cut to the mattress size and if necessary provided with the above-described fastenings.
The mattress cover described here provides an effective antibacterial/antiparasitical barrier: the effect is mainly of the mechanical type, obtained via the spunlace process and the optional phases of calendering, stretching and multistratification. This effect is supplemented by the chemical effect if the above antibacterial substances are used; in this case the two effects, mechanical and chemical, provide a combined action in achieving a total barrier.
The technology described here permits the production of said barrier with a modest use of material (weight of material per surface unit): this has the advantage of reducing the cost of the product and its overall dimensions and increasing ease of handling; at the same time the fine lightweight material does not substantially alter breathability and therefore does not create discomfort for the sleeper; lastly, the material is completely antiallergenic and non-irritating and if it contains antibacterial substances, they are incorporated in a stable fashion without the possibility of being released to the environment or towards the person.
The present invention is now illustrated via the following non-restrictive example.
Experimental Part
3 samples of spunlace fabric were produced (A, B C) according to the present invention. The fabric samples were placed on a sterile agar culture medium and were inoculated, on their upper surface, with 0.1 ml of a solution of Staphylococcus aureus spores. After an incubation time of 18 hours at 37° C., the growth of bacterial colonies on the upper surface of the fabric ( FIGS. 1 a , 2 a and 3 a ) was ascertained and, after removal of the sample, on the agar surface below ( FIGS. 1 b , 2 b , 3 b ). It is observed that for all the samples tested A, B and C, no bacterial growth occurred either on the inoculated surface or on the agar below. This demonstrates that the sheet subject of the invention effectively resists bacterial penetration.
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The present invention describes a new mattress cover sheet with barrier effect against bacteria and parasites, consisting of a spunlace fiber based fabric. The spunlace fabric mattress cover can be produced in a structure with one or more layers, and can contain antibacterial substances. The sheet subject of the invention provides an effective barrier between the person and the mattress, in particular avoiding the transfer of pollutants from the mattress to the person and at the same time protecting the hygiene of the mattress itself.
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BACKGROUND OF THE INVENTION
The present invention relates to automatic washers and more particularly to a wash basket for an automatic washer having agitation and spraying means associated therewith.
In automatic washing machines there generally is provided a basket for receiving clothes to be washed and an outer tub within which the basket is contained. In vertical axis machines oftentimes there is a central agitator which either oscillates or moves in some other fashion relative to the basket to enhance the flexing of the clothes in the wash fluid to improve washability. Generally in such washers, the liquid is introduced into the basket and clothes load through a nozzle fixed relative to the frame of the washer and protruding into an open top area of the basket, such as disclosed in U.S. Pat. No. 4,784,666.
In some constructions it is known to provide the laundry receiving vessel with a plurality of fins or other agitation enhancing devices protruding inwardly from the peripheral wall of the vessel. Such arrangements are shown in U.S. Pat. Nos. 1,627,931; 2,156,541; 2,575,691; 2,062,668; and 1,629,762.
In some constructions also known to provide a central vertically oriented structure which rotates or oscillates with the clothes receiving vessel. Such constructions are shown in U.S. Pat. Nos. 1,622,227; 1,849,896; 3,738,130; and 4,651,542.
SUMMARY OF THE INVENTION
The present invention provides a wash basket for receiving a load of fabric to be washed and which may be mounted concentrically within a tub for rotation and reciprocation relative to the tub. The wash basket has a peripheral wall and a central post mounted therein for rotation with the basket. The central post provides a liquid conduit for carrying wash liquid from the tub to a spray means. Preferably a spray means is mounted on the post for spraying wash liquid into the interior of the wash basket. Also, agitation enhancing means are positioned adjacent the peripheral wall of the basket for enhancing agitation of the fabric load.
The agitation enhancing means may comprise either or both of a spray means adjacent the peripheral wall to inject a spray of wash liquid into the interior of the tub or vertical fins carried on the peripheral wall.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view, partially cut away, of an automatic washer embodying the principles of the present invention.
FIG. 2 is a side sectional view showing certain interior components of the washer of FIG. 1.
FIG. 3 is a plan view of the washer with the top wall of the cabinet removed.
FIG. 4 is a side sectional view of a centrifugal valve arrangement as shown in FIG. 2.
FIG. 5 is a side sectional view of the centrifugal valve arrangement of FIG. 4, rotated 90°.
FIG. 6 is a top view of the valve arrangement of FIG. 4.
FIG. 7 is a side elevational view of the spray nozzle of FIG. 2.
FIG. 8 is a top view of the spray nozzle of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 there is illustrated an automatic washing machine generally at 10 having an exterior cabinet 12 with a top cabinet panel 14 and an openable lid 16 thereon. A control console 18 has a plurality of controls 22 to operate the washer through a series of washing, rinsing and fluid extraction steps. The openable lid 16 provides access to a top opening 24 through which a load of clothes can be placed into a perforate basket 26 which is concentrically carried within an imperforate tub 28.
In the place of a conventional agitator there is a central rigid post 30 which is mounted so as to be fixed relative to the basket 26, and thus to be rotatable with the basket, along a central vertical axis thereof.
Although the post 30 is shown as being a cylindrical member, it should be understood that the post could be any type of vertical structure and could have any type of geometric configuration.
The tub and basket assembly is supported by a conventional suspension system, including a plurality of legs 36 which are secured to a bottom frame 38. Counterbalancing means 40 are secured between the legs and another portion 42 of the suspension system. An electric motor 44 operates to drive the basket 26 in a rotary motion or in an oscillating motion depending on the particular wash cycle.
FIG. 2 shows the interior of the washer in greater detail in which it is seen that there is a drain area 48 positioned at a bottom of the wash tub 28 which connects to an outlet conduit 50. The outlet conduit 50 connects to a pump 52 which may be driven by a second motor 54. Proceeding from the pump 52 is a conduit 55 which has a Y connection with a first leg 56 and a second leg 58. In the Y connection there is a pivotable valve member 60 which is operated by a solenoid 62 to close either the first portion 56 or second portion 58. The second portion 58 extends to a drain for disposal of liquid in that portion and the first portion 56 attaches to an inlet fitting 64 for directing wash liquid into the interior of the post 30.
The inlet fitting 64 is formed on a coupling member 66 which is secured by means of appropriate fastening devices 68 to the portion 42 of the suspension system. The coupling member 66 is thus rigidly held against rotation. The coupling member 66 has formed therein a central passage 70 within which is received a drive member 72 which is to be coupled to the motor 44 either directly as shown in FIG. 2 or indirectly such as by means of belts, gears, clutches or other known power transmission arrangements.
The drive member 72 is free to rotate within the coupling member 66. The coupling member 66 has a radially directed passage 74 therein which opens through the connector 64 and which joins with an annular channel 76 formed in an interior diameter of the passage 70. The drive member 72 has a plurality of radial passages 80 which extend from an outer surface of the drive member to a central bore 82. Thus, wash liquid which flows in through conduit 56 and through passage 74 in the coupling member 66 will flood the annular channel 76 and be caused to flow into the radial passages 80 and into the bore 82 within the drive member. Appropriate seals 84, 86 are provided to prevent leakage of wash liquid along an outer surface of the drive member 72.
The drive member 72 is connected at an upper end, by appropriate fasteners 90 to a plate 92 secured to a spin tube 94. The spin tube 94 is connected to the wash basket 26 by a clamping arrangement at 96 within the post 30 as is known in the art. Thus, the basket will be drivingly connected to the drive member 72. The wash tub 28 is connected in a known manner at 98 to a centering tube 100. Carried within the spin tube 94, and rotating with it is a conduit tube 102 which communicates, at a bottom end 104 thereof with the bore 82 in the drive member 72. A top end 106 of the tube 102 is closed by a cap 108. At least two openings 110 are provided in the tube 102 which communicate with a centrifugal valve arrangement 112.
The centrifugal valve arrangement 112 is shown in greater detail in FIGS. 4-6.
The centrifugal valve arrangement 112 consists of a valve body 114 which has a bottom wall 116 with an opening 118 therethrough for receiving the tube 102. A central horizontal wall 120 is spaced above the bottom wall 116 so as to provide a chamber 122 within the valve body 114 within which are positioned the openings 110 in the tube 102.
The chamber 122 communicates with a pair of passages 124 disposed across from one another which lead radially outwardly from the chamber 122 and, at a radially outward position extend upwardly in a vertical passage portion 126 (FIG. 5). At the top of the vertical passage portions 126 there are two horizontal passages 128, bounded by a lower conical wall 130, which provide communication between the vertical passage portions 126 and a pair of upper chambers 132. The upper chambers 132 are generally cylindrical and are oriented radially, but at an angle from horizontal. Within each of the chambers 132 there is carried a ball 134 which is free to move within the chamber but which is sized to have a diameter approximately the same as the chamber.
When the basket 26 and thus the post 30 are at rest or are oscillating relatively slowly, the balls 134 will position themselves at a lower, radially inward end of the upper chamber 132 under the influence of gravity as shown in full lines in FIG. 2 and in phantom in FIG. 4. As this occurs, wash liquid which is directed by the pump 52 up through the tube 102 will follow the flow path indicated by arrow 140 (FIGS. 4 and 5). The wash liquid will leave the chambers 132 through an opening 142 at an upper, radially outward end of each chamber and will then flow into a space 144 between the valve body 114 and the center post wall 30.
As best seen in FIG. 2, the space 144 communicates at a bottom end 146 with a plurality of radial passages 148 extending along a bottom wall 150 of the basket to a plurality of vertical fins 154 formed at angularly spaced locations on the peripheral wall of the basket. At a junction 156 of the radial passages 148 with the fins 154 there are provided a plurality of apertures 158 providing communication between the radial passages 148 and the interior of the wash, basket thus providing a radially inwardly directed spray. Thus, when the wash basket is in the oscillation mode, with the pump 52 running, wash liquid will be recirculated from the drain 48 in the tub 28 to be reintroduced into the basket through the spray apertures 158.
When the wash basket is in a spin mode in which the basket spins at a relatively high rate of speed, centrifugal force causes the balls 134 to automatically move radially outwardly and thus upwardly in the cylindrical chambers 132 to effectively seal the openings 142. Wash liquid from the pump 52 then follows a flow path indicated by arrow 160 (FIGS. 4 and 6). When the wash liquid arrives in the cylindrical chambers 134, with the openings 142 blocked, the wash liquid exits through an opening 162 at a lower end of each cylindrical passage 132 into an annular space 164 between the valve body 114 and the tube 102.
The angle of the chambers 134 is selected, dependent on the weight of the balls 134, such that the balls will move outwardly when the rotation of the basket exceeds a predetermined speed which is greater than the rotational speed of the basket during the agitation portion of the wash cycle, but less than a rotational speed of the basket during the spin portion of the wash cycle.
Again as best seen in FIG. 2, the wash liquid continues to flow upwardly through a short tube 166 secured to a top of the post 30 and exits through a plurality of radial openings 168 into a chamber 170 formed in a nozzle member 172. The nozzle member 172 is shown in greater detail in FIGS. 7 and 8. The chamber 170 of the nozzle member 172 communicates with a vertically oriented spray nozzle opening 174 such that a wide fan of spray will be discharged from the nozzle in a vertical orientation. The nozzle member 172 is rotatingly supported on the short tube 166 and the nozzle opening 174 is oriented in a non-radial direction, preferably a tangential direction, and is offset from the rotational axis of the nozzle member, such that the reaction force of wash liquid leaving the nozzle will cause the nozzle member 172 to rotate on the tube 166 thus causing the nozzle member 172 to rotate relative to the basket. In this manner the wash liquid will be evenly distributed around the entire interior periphery of the basket through a horizontal extent of the full height of the basket while the basket is in the spin mode.
The washing machine construction disclosed herein is particularly suited for use with a wash method such as that disclosed in U.S. Pat. No. 4,784,666, assigned to the assignee of the present invention, and incorporated herein by reference. Specifically, such a washing process contemplates the use of a concentrated detergent solution, in the range of not less than 0.5% to 4% detergent concentration, in a limited amount, being sprayed against a rotating clothes load in the absence of mechanical agitation and recirculated through the clothes load a plurality times to effect a first cleaning step. When such a process is incorporated into the presently described machine, the nozzle member 172 will direct the concentrated wash fluid through the nozzle opening 174 against the spinning clothes load and, in view of the geometry of the nozzle opening, the wash liquid will be directed against the full height of the clothes load which will be held against the basket wall by centrifugal force. With the nozzle member 172 rotating relative to the basket 26, a complete wetting of the clothes load will be assured.
Following the initial concentrated wash step, additional water is introduced into the wash load to dilute the concentrated solution to a more normal or conventional concentration and a second washing step occurs during which time the clothes are agitated within the wash liquid bath. Although the presently disclosed washer does not include a centrally mounted agitator, the fins 154 projecting inwardly of the basket will provide an agitation force against the clothes load within the basket. Also, there may be fins of a similar construction on the post itself which will also impart an agitation force to the clothes load during oscillation of the basket.
Further, during the agitation portion of the wash cycle, wash liquid will be introduced and recirculated into the wash basket through the spray apertures 158 thus providing additional agitation force to the clothes load.
After the second washing step, the wash liquid is drained from the tub and the wash basket is spun to extract as much liquid from the clothes load as possible. Subsequently a rinsing of the clothes load occurs during which time water is sprayed against the rotating clothes load to remove dirt and detergent from the clothes. Part of such a spray rinse step could include a recirculation of the rinse spray which is collected in the tub and is redirected to the spray nozzle 172 by the pump, or fresh water may be delivered to the rotating clothes load with the collected water directed to drain. The fresh water would be directed into the spinning basket through a stationary nozzle member 180 (FIG. 2).
As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.
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A reciprocating laundry basket for an automatic washer is provided in which the basket has a peripheral wall, a bottom wall contiguous with the peripheral wall, a post mounted within the basket for rotation with the basket, a spray device mounted on the post for spraying wash liquid into the interior of the wash basket and spray inlets and vertical fins positioned adjacent the peripheral wall for enhancing agitation of the fabric load.
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FIELD OF THE INVENTION
The present invention generally relates to a sewing device for producing a seam having a fastening seam and a tacking seam, which in particular forms a bar tack configuration produced by means of zig-zag-stitching besides normal stitching.
BACKGROUND OF THE INVENTION
In U.S. Pat. No. 4,347,797 there is described an automatic sewing machine incorporating a sewing head, in which the reciprocating needle bar is guidingly received in a tiltably suspended bracket in order to impart to the needle bar besides its main reciprocating movement lateral jogging motions. For this purpose a gear mechanism drivingly connected to the arm shaft is provided, in which two linkage mechanisms operating at different RPM-rates are each selectably connectable to the needle carrying bracket. Due to the transmitting ratio of 1:1 or 1:2 of the linkage mechanism selectable different movements can be generated at the needle.
A disadvantage of this gear mechanism is presented by the fact that this mechanism can be shifted resp. altered with respect to its transmitting ratio at a comparable low RPM-rate, i.e. a shifting can be carried out only up to the maximum of about 80 RPM. Furthermore, such shifting even at low RPM-rates cannot be performed noiselessly and thus not without any wear occuring at elements to be engaged. Moreover, a shifting of this gear mechanism in full operation and under full load is basically not possible.
According to a modified embodiment described in the aforementioned U.S. patent it is proposed to employ two independent drive motors in order to separately generate the two movements of the needle, i.e. the main reciprocating vertical needle movement and the lateral jogging resp. zig-zag movement of the needle. As these motors must be controlled by a computer this presents a cost consuming method.
SUMMARY OF THE INVENTION
It is a main object of the present invention to provide an automatic sewing machine equipped with a sewing head comprising a needle jogging gear mechanism that renders possible a shifting resp. an alteration of a needle jogging movement of a transmitting ratio of 1:1 to 1:n with respect to its vertical main reciprocating movement or vice versa, at which a shifting can be performed under full load and without any limitations due to its operating rate, wherein "n" in the last mentioned proportion stands for the No. 2, 3 or 4.
Another object of the invention is to provide an automatic sewing machine installed with a sewing head having a needle jogging gear mechanism which is reliable in operation and simple in design.
According to the invention, there is provided an automatic sewing machine for producing a seam having a fastening seam and a tacking seam, said machine comprising a sewing head including a bearing bracket oscillating in one plane, a reciprocating needle bar mounted in said bearing bracket and carrying a needle and drive means imparting to said needle bar controllable lateral oscillating movements, the oscillating movement and the needle movement having a transmission ratio of 1:n (with n=2, 3 or 4) and which can be selectively engaged with a control drive of the bearing bracket, an oscillating movement also being produced during the production of the fastening seam, the oscillating movement and the needle movement having a transmission ratio of 1:1; means for receiving and clamping a workpiece; a guiding device for producing a continuous relative movement between the sewing head and a workpiece held by said clamping means in accordance with a predetermined seam course, the guiding device producing the relative movement in the oscillating plane of the bearing bracket during the production of the fastening seam; a first bearing mounting said needle bar in said bearing bracket and being drivable in the transmission ratio 1:n by means of a first drive mechanism and a second bearing mounting said needle bar in said bearing bracket and being drivable in the transmission ratio 1:1 by means of a second drive mechanism, said two bearings being arranged to be oscillatingly driven independent of one another and each drive mechanism being engageable independently of the other.
The objects of the present invention are achieved by the provision of individually oscillatable needle bar receiving bearings, wherein one of which can be oscillated in a transmitting ratio of 1:1 with respect to the arm shaft and wherein the other one of which is oscillatable in a transmitting ratio of 1:n with respect to the arm shaft.
The arrangement of the oscillatable bearings in rocking levers operating about a common axis leads to a simple construction. Due to the 1:1 transmitting ratio it is possible to generate a needle jogging movement at the same frequency as the needle main reciprocating movement, i.e. the needle is moved also at the penetration of the workpiece to be sewn.
As the bearings receiving the needle bar are individually oscillatable by independent drives it is possible to carry out a shifting regardless of the kind of operating condition, i.e. at full load and also at full RPM-rate, e.g. 2500 to 3500. At these two shifting conditions one of the bearings must be brought into a stationary position as the other one will be oscillated by the individually coupled jogging mechanism. Basically it is also possible to arrange the bearings in such a way that the oscillating movements of the bearings are achieved in different planes. This of course then would also require the angular relation of the hook position about the longitudinal needle axis to be controlled.
With the embodiment of the invention it is also proposed to employ the same elements for both the lower and the upper bearing.
According to another feature of the invention a simple construction is achieved to derive oscillating movements of different frequencies from the main drive element of the sewing head, i.e. from the arm shaft of the latter.
According to an embodiment of the invention, it is possible to steplessly alter the amplitude of the individual oscillating movement. Moreover, it is proposed to provide an additional mechanism to limit the adjustments for altering the amplitude in a simple manner.
Other objects, advantages and features of the present invention will appear from the detailed description of the preferred embodiment including an additional embodiment of the control mechanism, which will now be explained in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of one embodiment of an automatic sewing machine according to the invention;
FIG. 2 is a top plan view of the automatic sewing machine shown in FIG. 1;
FIG. 3 is a partially broken open longitudinal view of the sewing head of the automatic sewing machine, on an enlarged scale;
FIG. 4 is a vertical longitudinal section taken through a part of the arm of the sewing head illustrated in FIG. 3, on an enlarged scale;
FIG. 5 is a partial front view of the arm of the sewing head taken in the direction of the arrow V in FIG. 4 but with the cover removed;
FIG. 6 is a top plan view, partially in section of the driving elements of the sewing head taken in the direction of the arrow VI in FIG. 5;
FIG. 7 is a partial top plan view of the arm of the sewing head taken in the direction of the arrow VII in FIG. 4 but with the cover removed;
FIG. 8 is a sectional view of the arm of the sewing head taken on the line VIII--VIII in FIG. 7 in the direction of the arrows;
FIG. 9 is a partial section of the arm of the sewing head taken on the line IX--IX in FIG. 7 in the direction of the arrows;
FIG. 10 shows a workpiece comprising a workpiece cut with a pocket cut sewn thereon by a double seam produced by the automatic sewing machine according to the invention;
FIG. 11 shows the path of motion of the laterally vibrating needle point when sewing tack switches;
FIG. 12 shows the path of motion of the laterally vibrating needle point when sewing fastening stitches;
FIG. 13 is a partially sectional view according to FIG. 8 providing a stepless adjustable adjusting shaft; and
FIG. 14 is a partial side elevation of the arm of the sewing head taken in the direction of the arrow XIV in FIG. 13.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2 there is illustrated an automatic sewing machine mounted on a stand 2 having a plate 4, which is fastened thereto by means of posts 3 for receiving a sewing head 5 with a needle 6. On the plate 4 there is arranged a workpiece supporting plate 7 extending with a semicircular portion 8 around the needle 6 of the sewing head 5 (FIG. 2). On the workpiece supporting plate 7 there is clamped a workpiece cut 9 together with a pocket cut 10 by means of a clamping plate 11 having a U-shaped recess 12, along which the workpiece cut 9 and the pocket 10 are to be sewn together.
The clamping plate 11 is installed with a shaft 13 and a timing belt pulley 14, at which the shaft 13 is pivoted in one end 15 of a square-formed tubular arm 16 of a guiding device 17. The timing belt pulley 14 co-operates with a timing belt 18 located in the arm 16. The timing belt 18 serves to rotate the clamping plate 11 into a determined angular position with respect to the arm 16 as hereinafter described.
Within the stand 2 there is arranged a gear 19, a vertical shaft 20 of which is pivoted in a tube 21 and carries a control cam 22 which is provided at its lower surface 23 with two grooves 24, 25, at its upper surface 26 with a groove 27 and at its periphery 28 with a cam 29 for actuating a switch 30.
The other end 31 of the arm 16 of the guiding device 17 is linked by means of a shaft 32 to a lever 33, which carries a cam follower 34 co-operating with the groove 24. The free end 35 of the lever 33 is pivoted to an axis 36 of the stand 2. Within the arm 16 the shaft 32 is provided with a timing belt pulley 37 receiving the timing belt 18. A further timing belt pulley 38 arranged within the square-formed tubular lever 33 receives a further timing belt 39, which extends within the lever 33 and co-operates with a timing belt pulley 40 pivoted on the axis 36. The timing belt pulley 40 is provided with a pinion (not shown), which meshes with a gear wheel 41 mounted on a lever 42. The lever 42 is pivoted about the center axis of the gear wheel 41 located at the stand 2. The free end of the lever 42 carries a cam follower 43 cooperating with the groove 25 formed at the lower surface 23 of the control cam 22.
The axis 36 firmly connected to the stand 2, receives a further lever 44, which is provided with a cam follower 45 co-operating with the groove 27 formed at the upper surface 26 of the control cam 22. The free end of the lever 44 is linked to the arm 16 by means of bolts 46, 47 and a connecting bar 48. The levers 33, 44, the arm 16 and the connecting bar 48 form a linkage mechanism having the shape of a parallelogram.
Between the workpiece supporting plate 7 and the connecting bar 48 the stand 2 is formed with a recess 49 extending parallelly with respect to the sewing head 5. Furthermore, inside of the stand 2 there is provided a drive mechanism 50. A motor 51 of said drive mechanism 50 drives a shaft 53 via a belt drive 52. The shaft 53 is drivingly connected to the sewing head 5 by means of a clutch 54 and a belt drive 55. Moreover, the shaft 53 is connected to the gear 19 by means of a belt drive 56.
As illustrated in FIG. 3, the sewing head 5 is formed with an overhanging arm 57 connected to a base plate 59 by means of a standard 58. In the arm 57 there is pivoted an arm shaft 60, the outer free end of which is provided with a handwheel 61. The arm shaft 60 is driven by the belt drive 55 and drivingly connected via a timing belt drive 62 located in the standard 58 to a shaft 63 located in the base plate 59. Furthermore, in the base plate 59 there is pivoted a looptaker 64, which is driven via a spur gearing (not shown) by the shaft 63.
As illustrated in FIG. 4, the arm shaft 60 terminates in a crank 65 with a crank pin 66 receiving the upper end of a needle bar drive lever 67. The lower end of the needle bar drive lever 67 is pivoted on a lug 68 forming a part of a drive member 71 secured to a needle bar 70 by means of a setscrew 69. To the lower end of the needle bar 70 there is fastened the needle 6 by means of a setscrew 72. The needle bar 70 is displaceably received in an upper bearing 74 and a lower bearing 75. As the bearings 74, 75 are formed identically, hereinafter only the lower bearing 75 is described. This bearing 75 is formed as a hollow cylinder with an inner cylindrical bearing surface 76 for receiving and guiding the needle bar 70. Furthermore, the lower bearing 75 is provided with two outer conical recesses 77 arranged on an axis extending perpendicularly and diametrically with respect to the longitudinal axis of the bearing surface 76.
In the overhanging arm 57 of the sewing head 5 there is pivoted a hollow shaft 78 extending below and parallelly to the arm shaft 60. The hollow shaft 78 is formed with a shoulder 79 and two bearings 80, 81. To the end of the hollow shaft 78 turned to the needle bar 70 there is secured a lever 82 by means of a clamping member 83. In its middle area 84 the lever 82 has a downwardly opened U-shaped profile. The free end of the lever 82 is provided with a ring 85 surrounding with play the lower bearing 75 of the needle bar 70. Two screws 86 are screwed into the ring 85 and secured by lock nuts 87. At their ends directed to the center of the ring 85, the screws are formed with points (not denoted) engaging the conical recesses 77 of the lower bearing 75 as the bearing 75 is freely swingable about them. The afore-described connection of the lower bearing 75 of the needle bar 70 to the lever 82 ensures that the lower bearing 75 is swingable about an axis defined by the position of the points and the conical recesses 77 extending parallel with respect to the hollow shaft 78 resp. the arm shaft 60.
Within the hollow shaft 78 there is rotatably received in bearings 80, 81 an inner shaft 88, the other end of which turned to the handwheel 61 is rotatably supported in a further bearing 89 located in the overhanging arm 57 of the sewing head 5. The end turned to the needle bar 70 engages a connecting member 90 of a rocking lever 91 secured thereto by means of a pin 90'. The rocking lever 91 is formed with two ribs 92, 93 embracing the needle bar drive lever 67 with clearance. The outer ends of the ribs 92, 93 are firmly connected to the connecting member 90. From here they diverge in an acute angle in order to terminate in a connecting web 94. The connecting web 94 is provided with a bore (not denoted), in which rotatably engages a pivot pin 95. The pivot pin 95 is secured to a rib 96 of the overhanging arm 57 of the sewing head 5 by means of a setscrew 97. Consequently, the rocking lever 91 is swingable about an axis extending coaxially with respect to the longitudinal axis of the hollow shaft 78 resp. the inner shaft 88.
Two ribs 98, 99 each extend from the ribs 92, 93 upwardly to the upper bearing 74 of the needle bar 70 and terminate in a ring 100. For receiving the upper bearing 74 the ring 100 is formed according to the already described ring 85 of the lever 82. By the connection of the upper bearing 74 to the lever 91 it is ensured that also the upper bearing 74 is swingable about an axis extending parallelly to the hollow shaft 78 resp. the inner shaft 88. As the needle bar 70 is supported in the upper bearing 74 and the lower bearing 75 in order to allow a longitudinal displacement, the two bearings 74, 75 are relatively positioned in alignment.
To the inner shaft 88 there is clamped a lever 101 axially supporting a double gear wheel 102, which is pivoted to the inner shaft 88. The double gear wheel 102 is provided with two identical toothed rims 102a and 102b.
The toothed rim 102a is connected via a timing belt 104 to a gear wheel 103 having the same diameter. The timing belt pulley 103 is pivoted to the arm shaft 60. Thus, the timing belt drive 105 formed by the toothed rim 102a of the double gear wheel 102, the timing belt 104 and the timing belt pulley 103, has a transmitting ratio of 1:1. The other toothed rim 102b of the double gear wheel 102 is connected via a timing belt 107 to a timing belt pulley 106 having a double large diameter than the toothed rim 102b. The timing belt pulley 106 is pressed together with a thrust washer 108 onto a tubular shoulder 109 of an eccentric 110. The eccentric 110 is pivoted to the arm shaft 60 and axially secured in one direction by the timing belt pulley 103 and in the other direction by a collar 111 fastened to the arm shaft 60. The timing belt drive 112 formed by the toothed rim 102b of the double gear wheel 102, the timing belt pulley 106 and the timing belt 107, has a transmitting ratio of 1:2. Consequently, the eccentric 110 is driven by the timing belt drives 105, 112 at the half RPM-rate of the arm shaft 60.
The eccentric 110 is movably embraced by an eye 113a of a pitman 113. The eye 113a of the pitman 113 is axially guided by the thrust washer 108 and a disc 114 arranged on the eccentric 110 and fastened thereto by means of a retaining ring 115. Thus, by the guidance of the eye 113a also the pitman 113 itself is kept in position.
The free end of the pitman 113 is swingably connected to a double armed lever 117 by means of a bolt 116. The double armed lever 117 is formed with an upper arm 118 and a lower arm 119. The lower arm 119 is swingably connected via a bolt 120 to the free end of the lever 101. At the free end of the upper arm 118 there is fastened via a bolt 121 a guide block 122. The guide block 122 is displaceably supported in a guideway 123, which is formed in a shoulder 124 of an adjustment shaft 125. The adjustment shaft 125 is rotatably received in two split bearings 126 mounted to the overhanging arm 57 of the sewing head 5 and secured thereto by means of screws 127. On the one hand the adjustment shaft 125 is secured against axial displacement by the shoulder 124 and on the other hand by an oppositely arranged shoulder 128. Furthermore, to the adjustment shaft 125 there is fastened a radially extending lever 129. To the end of the lever 129 there is hinged a fork 130 by a bolt 131. The fork 130 is a part of a piston rod 132, the free end of which is provided with a piston 133. The piston 133 together with the piston rod 132 is received in a cylindrical housing 134 and displaceable in the longitudinal direction of the piston rod 132. At the exit end of the piston rod 132 the housing 134 is closed by a cover 135. The housing 134 defines together with the piston 133 and the piston rod 132 a first drive element 136, which is movable between two end positions and provided with connections 137, 138 for air pressure supply. Furthermore, the housing 134 receives a second drive element 139, which corresponds in construction with the first drive element 136 and is provided with connections 140, 141 for air pressure supply. The first drive element 136 and the second drive element 139 form a pneumatic control drive 142 shiftable into several--maximal four--shifting positions. At the free end of its piston rod 143 the second drive element 139 is formed with a fork 144 hinged by a bolt 145 to a bearing 147 located at the overhanging arm 57 of the sewing head 5 and secured thereto by a screw 146.
On the contrary to the afore-described part of the gear mechanism provided with an eccentric 110 freely rotatable on the arm shaft 60, the hereinafter described part of the gear mechanism is provided with an eccentric 148, which is firmly secured to the arm shaft 60. The eccentric 148 is similarly connected with further elements as already described in conjunction with the aforesaid part of the gear mechanism so as to produce variable oscillatory movements at the hollow shaft 78. As the construction of this part of gear mechanism corresponds to the already described part of the gear mechanism, the same or comparable components are denoted with the same reference numerals but with the addition of a prime. Insofar, it may be referred to the above description. However, the lever 101' is not clampingly connected to the inner shaft 88 as the lever 101 but to the hollow shaft 78.
As is clear from FIG. 4, the end of the inner shaft 88 turned to the handwheel 61 is provided with a collar 149. At its front and upper surface the overhanging arm 57 of the sewing head 5 is closed by removable covers 150, 151 (FIG. 3).
Operation of the described automatic sewing machine is as follows:
After the workpiece cut 9 and the pocket cut 10 are clamped together by means of the clamping plate 11, the sewing procedure may be initiated. The shaft 53 is driven via the belt drive 52 by the motor 51 for driving on one hand the sewing head 5 via the clutch 54 and the belt drive 55, and, on the other hand, the gear 19 via the belt drive 56. The control cam 22 is driven via the vertical shaft 20 of the gear 19. Due to the co-operation of the cam followers 34, 35 with the grooves 24, 27, the arm 16 and the clamping plate 11 are displaceable parallelly with respect to the workpiece supporting plate 7 in both associated co-ordinate directions. Due to the co-operation of the cam follower 43 with the groove 25, the clamping plate 11 may also be rotated about the shaft 13 via the timing belts 39, 18. Consequently and according to the above described manner, any movement of the workpieces 9, 10 relative to the needle 6 may be achieved.
The co-operation of the cams 29 located at the periphery of the control cam 22, with the stationarily arranged switch 30 renders possible further control functions, i.e. for actuating the clutch 54 allowing an idling movement of the clamping plate 11 without simultaneously driving the sewing head 5, stopping the motor 51 at the end of a sewing cycle, or releasing shift functions within the sewing head 5. The geometrical contour of the seam to be produced in the workpieces 9, 10 is defined by the configuration of the grooves 24, 25, 27 provided in the control cam 22. Of course, the contour of the grooves 24, 25, 27 and thus the contour of the seam must correspond to the profile of the recess 12. The function as so far described is known from U.S. Pat. No. 4,347,797.
When the sewing head 5 is operated, on the one hand the arm shaft 60 drives via the timing belt drive 62 and the shaft 63 the looptaker 64 arranged in the base plate 59, and possibly further commonly employed elements. On the other hand the arm shaft 60 drives the needle bar 70 with the needle 6 in the usual vertical reciprocating direction via the crank 65, the needle bar drive lever 67 and the drive member 71.
As the needle bar 70 is supported in the bearings 74, 75, which are independently swingable to each other, it is possible to impart to the needle bar 70 regardless of its vertically directed stroke movement also a lateral jogging motion extending in direction of the arrow 152 (FIG. 5), i.e. in the regular sewing direction.
The eccentric 110 drivingly connected to the arm shaft 60 via the timing belt drives 105, 112 steadily imparts rocking motions by means of the pitman 113 to the double armed lever 117. As is clear from FIG. 8, the adjustment shaft 125 is positioned in a neutral position due to the position of the control drive 142.
In such a neutral position the guideway 123 situated in the stud 124 of the adjustment shaft 125 longitudinally extends in an axis perpendicularly positioned with respect to an axis crossing the center of the bolt 120 and the axis of rotation of the adjustment shaft 125. In such position the pitman 113 imparts only a rocking movement to the double armed lever 117, which oscillates about the center of the bolt 120 and which is linearly oscillated due to the movement of the guide block 122 in the guideway 123. Essentially, the double armed lever 117 does not impart rocking movements in its longitudinal main direction regardless of minor movements due to the linear extension of the guideway 123 instead of an extension according to an arc having a center corresponding to the center line of the bolt 120. Consequently, no oscillating movement is imparted to the inner shaft 88 including the upper bearing 74 by means of the firmly connected lever 101, i.e. the upper bearing 74 receiving the needle bar 70 is kept stationary.
Due to the rotation of the arm shaft 60 furthermore, the eccentric 148 imparts rocking movements via the pitman 113' and thus also the double armed lever 117'. According to FIG. 9 by the extended piston rods 132' and 143' of the control drive 142' the adjustment shaft 125' is tilted in such a position, in which the guideway 123' located in the stud 124' is tilted in a counterclockwise direction. Due to this tilted position of the guideway 123', the double armed lever 117 is now exposed also to a component of movement extending in the longitudinal direction. Due to the movement of the double armed lever 117', the guide block 122' rocks in the guideway 123' causing an oscillating movement of the lever 101' and thus also an oscillating movement of the hollow shaft 78. The hollow shaft 78 transmits its oscillating movements by means of the lever 82 to the lower bearing 75, which extends out of the arm 57 with play through an opening 152a. As the eccentric 148 is firmly connected with the arm shaft 60 the needle bar 70 and thus the needle 6 performs a complete lateral movement as the needle 6 describes a complete movement of stroke. At these superimposed movements, the tip 153 of the needle 6 travels along the closed path 154 as illustrated in FIG. 12. In FIGS. 11 and 12 the upper side 155 of the workpiece supporting plate 7 is illustrated by a line parallelly extending to the individual direction of stitching. The dimension "a" indicates the distance which the tip 153 of the needle 6 travels as the needle 6 penetrates the workpiece cut 9 and the pocket cut 10 to be sewn together. Since the needle 6 performs beside the necessary vertical main movement additionally also a lateral movement which takes place also as the workpieces 9, 10 are being penetrated by the needle 6, the movement of the latter will be considered as a needle feed movement. Due to the coaction of the guiding device 17 moving the workpieces 9, 10 with respect to the needle 6 in conjunction with the superimposed movements of the needle 6 according to the path 154 the workpieces 9, 10 are stitched together by a fastening seam 156 (FIG. 10). As additionally the tilting of the clamping plate 11 about the shaft 13 by means of the groove 25 is carried out, the workpieces 9, 10 to be stitched are so aligned that the oscillating movement according to the arrow 152 of the needle 6 is always kept tangential with respect to the individual direction of the fastening seam 156 at its particular position of stitching.
After the termination of the fastening seam 156, the switch 30 will be triggered by one of the cams 29 situated at the control cam 22, by which the control drives 142, 142' are so shifted that the adjustment shaft 125' will be brought into a neutral position as already described in conjunction with the position of the adjustment shaft 125 and the adjustment shaft 125 will be brought into a tilted position, offset with respect to the neutral position. In these positions of the adjustment shafts 125 and 125', the lower bearing 75 will now be kept stationary and the upper bearing 74 will be rockingly moved. Due to the drive of the eccentric 110 via the timing belt drive 112 the RPM-rate of the eccentric 110 is half of that of the arm shaft 60 i.e. the transmitting ratio 1:2 becomes effective. Due to this action, the upper bearing 74 is exposed to an oscillating movement at which the tip 153 of the needle 6 travels along a path 157 as illustrated in FIG. 11. At this movement the needle 6 describes two complete stroke movements as one lateral movement according to the direction of the arrow 152 is completed. At this kind of movement the needle 6 almost does not carry out a movement in the direction of the arrow 152 while penetrating the workpieces 9, 10. This becomes clear from FIG. 11 as the contour of the path 157 extends almost vertically with hardly any lateral movement from the upper side 155 of the workpiece supporting plate 7 downwardly. At this kind of movement a tacking seam 158 will be produced composed of individual zig-zag switches. This kind of movement of the needle 6 is also referred to as a zig-zag movement. The dimension "b" illustrated in FIG. 11 represents the amplitude of the needle 6 at the upper side 155 of the workpiece supporting plate 7 which corresponds to the bight of the zig-zag stitches of the tacking seam 158.
Dependent on the shift condition of the control drive 142--at extended piston rods 132, 143 or retracted piston rods 132, 143, it may be achieved that the adjustment shaft 125 will be tilted in a clockwise resp. a counterclockwise direction. For example, the extended position of the corresponding piston rods 132', 143' is shown in FIG. 9, in which the adjustment shaft 125' is tilted to its final counterclockwise directed position. Due to this kind of angular position of the adjustment shaft 125', it is achieved that the tip 153 of the needle 6 moves along the path 154 in the direction of the arrow 159 resp. in opposite direction of the arrow 160. In the same manner, it can be achieved by positioning the adjustment shaft 125 accordingly, that the tip 153 of the needle 6 moves on the path 157 beginning from its upper position 161 at first in the direction of the arrow 162 resp. in the direction of the arrow 163 at the production of the tacking seam 158.
The activation of the control drives 142, 142' should be so interlocked as to expose one of the bearings 74, 75 to a rocking movement only.
As the angular position of the adjustment shafts 125, 125' determines the direction in which the tip 153 of the needle 6 moves along the paths 154 resp. 157 the value of the angle by which the shafts 125 resp. 125' are adjusted determines the amplitude denoted by the dimension "a" resp. "b" indicating the distance of movement of the tip 153 of the needle 6 at the upper side 155 of the workpiece supporting plate 7. Such different amplitudes are achievable by means of control drives, at which the first drive element 136 resp. 136' and the second drive element 139 resp. 139' can carry out adjustable strokes in order to render possible angular adjustments of different angles and thus the generation of different amplitudes in the one or the other swing direction. The adjustment shafts 125 resp. 125' may be angularly displaced of course for such an angle only as to still assure an unobstructed movement of the guide blocks 122, 122' in the corresponding guideways 123, 123'. For example, such adjustment may be for about an angle of 20° with reference to the neutral position of the adjustment shaft 125 resp. 125'.
In FIGS. 13 and 14 a modified construction is illustrated showing the possibility for limiting the angular adjustment of the adjustment shaft 125. The adjustment shaft 125 is formed at its stud 124 with an arm 164 profiled with a rounded free end 165. The arm 164 reaches with clearance through an opening 166 profiled in a wall 167 of the arm 57. At the wall 167 there are centrally arranged an upper lug 168 and a lower lug 169 with respect to the opening 166. Both lugs 168, 169 are each formed with bores including threads (not denoted), at which both bores are aligned to each other. The threaded bore of the upper lug 168 receives a threaded bolt 170 and the threaded bore of the lower lug 169 receives a threaded bolt 171. Both bolts 170, 171 are each formed with a respective slot 172 for a screwdriver and are secured in the respective lugs 168, 169 by means of respective lock nuts 173.
According to FIG. 13, the adjustment shaft 125 is displaced by the action of the control drive 142 into a final position in a counterclockwise direction, in which the rounded end 165 abuts against the front side 174 of the lower threaded bolt 171. In this shift position the piston 133 does not contact the cover 135, i.e. the first drive element 136 does not reach its maximal possible extended position.
A similar modification can be provided for the adjustment shaft 125'. By the possibility for limiting the amount of angular adjustment of the adjustment shaft 125 resp. 125' the amplitude of each generated oscillating movement can be steplessly altered, wherein the maximum possible extension of the individual drive element 136, 139 resp. 136', 139' corresponds to a dimension for the maximum possible amplitude. By the alteration of the stops, i.e. adjusting the threaded bolts 170 and 171, the amplitude can be accordingly decreased.
The invention is not restricted to the above-described embodiments but modifications and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.
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An automatic sewing machine for producing a seam having a fastening seam and a tacking seam is installed with a sewing head having a bearing bracket with two bearings which are arranged at a distance from each other for receiving a reciprocating needle bar including a needle. A sewing head comprises a drive mechanism to selectably impart jogging movements to the needle bar, wherein the movements form a transmitting ratio with respect to the reciprocating movement of the needle of 1:1 or 1:2.
In order to render possible a shifting of the needle jogging movement during the operation of the machine and under full load, the two bearings guidingly receiving the reciprocating needle bar are oscillatingly drivable independently of each other wherein one bearing is oscillatable at a transmitting ratio of 1:2 and the other bearing is oscillatable at a transmitting ratio of 1:1. Both bearings are drivingly connected to individual drive parts each of which is independently engageable.
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TECHNICAL FIELD
[0001] The technical field relates generally to three dimensional geometric rendering using point cloud methods for computer graphics, and more particularly relates to techniques for optimizing computer resources (e.g., memory, CPU, etc.) for the graphical rendering of point cloud objects.
BACKGROUND
[0002] Rendering real-time views of a three-dimensional computer models is a resource-intensive task. Classically, physical real-world objects are represented by a three-dimensional geometric model based upon vertices and edges which approximate the surface, texture and location of the real-world object. Thus, these objects are stored in a computer medium as a collection of polygons which are collected together to form the shape and visual and characteristics of the encoded real-world object. Alternatively, point clouds represent objects not as a collection of polygons, but rather as a sample of points representative of, and located on, the external surface (interior-inclusive, or interior-exclusive) of an object.
[0003] A point cloud is a set of vertices, often considerably large, having at least three-dimensional coordinates; these vertices are often defined by the classic 3-tuple (X, Y, Z) of three-dimensional rendering coordinates. Point clouds are used in situations where sampling a real-world object is practical and can produce a detailed representation of the real-world object. Sampling devices obtain a large number of points from the external surface of a real-world object, and output a point cloud array containing the vertices. Point cloud objects are desirable for many rendering applications, including manufactured parts, quality inspection, and a visualization, animation, rendering and mass customization applications.
[0004] Typically modern applications use polygonal meshes; point clouds are not commonly supported in commercial rendering applications with regards to manipulation, modification, creation and alteration. To manipulate point clouds, applications will convert the point cloud external surfaces into directional polygonal or tessellated triangle meshes, spline-form surfaces, or voxel models through surface data inspection and reconstruction. Further, common methods for rendering (as opposed to manipulating) point clouds similarly rely on conversion into polygonal meshes and then allow for common methods of manipulation, modification and alteration. In this manner, traditional models of progressive meshes and rendering techniques apply.
[0005] When rendering scenes containing advanced geometry, rendering complexity and performance are utmost resource considerations, and are managed carefully. A reduction in object complexity leads to improved rendering performance. A technique for reducing object complexity in a given scene is to alter the level of detail of the objects. Level of detail commonly involves decreasing the complexity of an object representation as it moves away from the viewer. The efficiency of rendering is improved by decreasing the graphics system load, usually by reducing vertex transformations. The reduced quality of the model is minimized because of the effect on object appearance when the object is rendered in the distance (or when moving at a rate that exceeds viewer perception).
[0006] Discrete Level of Detail (DLOD) provides for a fixed set of models, each representing the same object at a differing complexity level. Prior solutions to DLOD for polygonal rendering include pre-generating a fixed set of quantized models and selecting between models during rendering. Polygonal systems also pre-calculate fixed level of detail as mesh merging is computationally difficult, or resort to complex interpolation or transition methods such as progressive meshes or delta storage, where the differences between levels are stored and referenced during a conversion or mapping process from one level of mesh to another. Other analogous fixed level systems include MIP maps for texture rendering. Conversely, when a mesh is continuously evaluated and an optimized version is produced according to a tradeoff between visual quality and performance in any given frame, the result is Continuous Level of Detail (CLOD).
[0007] Point cloud rendering models use a fixed number of points per object, often managed using a space-partitioning method such as an octree or N-dimensional tree.
[0008] To implement discrete level of detail for a point cloud, fixed octree maps at specific discrete or “quantized” detail levels are formed, thus producing redundant and duplicate copies of data. This process is sometimes referred to as down-sampling. This also causes the visual illusion of “jitter” when an object, viewed during the render of a scene, transitions in Z-depth enough to trigger a move from one quantized level to another. For example, a visual representation of an object may have a low detail, medium detail and high detail, with the low detail shown at far distances, and the high detail shown at close distances. However, these point cloud models do not allow for smooth and dynamic transitioning detail, and are often used at larger viewing distances in the rendered world to avoid changes perceptible by the viewer, thus wasting rendering resources.
[0009] To compound the issue, real-world point clouds approximating physical object of any reasonable size can contain millions of points. Consequently, enormous computer resources are required to manage and render point cloud data of this type. Level of detail calculation is even more difficult in such large point cloud situations.
SUMMARY
[0010] In view of the foregoing, the invention provides a system of rendering point cloud objects with efficient continuous and dynamic level of detail. The invention performs a pre-computed reorder and/or resample of a point cloud object in an ordered set in a list form such that attributes of the point cloud are maintained across the entire list. In one embodiment, the N-axis centroid of the vertices of the set is maintained when iterating from the head of the list to the tail of the list. In another embodiment, the average surface point density of the vertices of the set are maintained when iterating from the head of the list to the tail of the list. The pre-computed ordering preserves properties of the point cloud object, specifically the point density when rendering through the list of points from head to tail, within an error tolerance.
[0011] An error tolerance for this approximation can be selected. During the rendering process, any level of detail can be specified dynamically and continuously rendered at a known cost from minimum detail, such as a single point or a minimum set, to maximum detail including the entire point cloud list, or any continuous level in between by iterating the render list until the desired detail level is reached. In one embodiment, a selection of the level of detail can be obtained by dividing the distance from the PCO to the camera position by the normalized available maximum level of detail. As an animated object travels from far to near the viewing position, the level of detail scales with the object, creating a high performance rendering scenario with minimized perception of point cloud detail change.
[0012] To the accomplishment of the foregoing and related ends, certain illustrative aspects of the disclosed and claimed subject matter are described herein in connection with the following description and drawings. Other advantages and novel features will become apparent from the following detailed description when considered in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The system and methods for controlling point cloud rendering in a 3D computer graphics system are further described with reference to the accompanying drawings in which:
[0014] FIG. 1 is a block diagram illustrating a computing system operable to execute the disclosed invention.
[0015] FIG. 2 is a block diagram illustrating a software and hardware rendering environment in which the invention may be embodied.
[0016] FIG. 3 is a block diagram illustrating a technique of producing an ordered point cloud list appropriate for rendering with dynamic level of detail.
[0017] FIG. 4 is a block diagram illustrating a technique of rendering an ordered point cloud list in accordance with an embodiment of the invention.
[0018] FIG. 5A illustrates rendering a point cloud object leveraging dynamic level of detail, with no cloud points rendered.
[0019] FIG. 5B illustrates rendering a point cloud object leveraging dynamic level of detail, where the level of detail is low (N=58).
[0020] FIG. 5C illustrates rendering a point cloud object leveraging dynamic level of detail, where the level of detail is moderate (N=551).
[0021] FIG. 5D illustrates rendering a point cloud object leveraging dynamic level of detail, where the level of detail is high (N=1558).
[0022] FIG. 5E illustrates rendering a point cloud object leveraging dynamic level of detail, where the level of detail is maximum (N=2100).
[0023] FIG. 6A illustrates the two dimensional determination of the barycenter of an object in accordance with an embodiment of the invention.
[0024] FIG. 6B illustrates the three dimensional determination of the barycenter of an object in accordance with an embodiment of the invention.
DETAILED DESCRIPTION
[0025] Overview
[0026] A new and improved method of precomputing (by resampling and/or reordering) point cloud objects to allow for variable or dynamic level of detail is presented. An embodiment can be leveraged on both sides of a 3D point cloud application—during the content production phase of a 3D application, and subsequently during the rendering phase of the 3D application. The developer of the application obtains point cloud lists representing objects to be used in the application. These models are obtained via physical object sampling including methods such as laser, photographic and depth sampling, or alternative methods such as 3D modeling packages. The precomputing phase of the dynamic level of detail method is applied at any stage prior to displaying the point cloud object, including a parallel computation while rendering other content. During the rendering phase, typically real-time, the precomputed level of detail is leveraged to obtain highly efficient and high performance rendering while at the same time producing a desirable visual display.
[0027] A point cloud (PC) is a set or “list” of vertices, often considerably large, having at least three-dimensional coordinates; these vertices are typically defined by the classic 3-tuple (X, Y, Z) of three-dimensional rendering coordinates. A point cloud list (PCL) refers to this list of vertices. Point clouds are used in situations where sampling a real-world object is practical and can produce a detailed representation of the real-world object for visual image rendering. Sampling devices obtain a large number of points from the external surface of a real-world object, and output a point cloud array containing the vertices. A point cloud object (PCO) is a point cloud list representing a point cloud for an object.
[0028] Level of detail (LOD) is the degree of detail rendered in a given 3D scene. LOD can be specified on a scene basis, or an object basis. A lesser rendering level of detail improves the efficiency and performance of rendering a particular object in a scene. Dynamic level of detail (DLOD) is a method for choosing level of detail based on factors in the scene, such as viewing distance, that can, for point clouds, represents the number of points needed for rendering a given object. A continuous dynamic level of detail entails that the levels are not discrete or are not pre-generated at fixed intervals. However, point clouds can be pre-calculated in ideal ways without the need for mesh merging or fixed levels of detail, thus enabling fast continuous level of detail.
[0029] A dynamic level of detail defined in this invention for point clouds can encompass both an actual point count, and also an index representing a position in a point cloud list. In some applications these measures may correspond to the same value. In others, the detail level may be “virtual” and require a mapping function to the actual point count or point index. For example, a detail level may be a floating point value that is rounded to an index. Minimum detail is a single point or a minimum point set necessary for rendering the object. When referring to maximum detail, typically this implies the entire point cloud list, however rendering applications may choose to set a lower maximum detail level to ensure high performance rendering.
[0030] Precomputing is a processor-based analysis of an object list, and may refer to both the first computing of a PCL or PCO, either prior to run time, or on the fly during run time, or a later computing that processes an existing PCL or PCO. Recomputing may be used interchangeably with precomputing or recalculation, however the term is sometimes used to refer to the reprocessing of existing data.
[0031] An embodiment preserves point density in an ordered point cloud object render list to establish dynamic level of detail. The established dynamic level of detail can then be leveraged through a pre-ordered point cloud list to render a point cloud object using variable or dynamic level of detail. One method of establishing the dynamic level of detail is to use a distance to viewed object as a scalar value to determine the stop element in the point cloud list. A stop element becomes the furthest progression in the list that is iterated to achieve sufficient detail at that level of detail setting. The point cloud object element list allows for a single copy of the object to remain in memory, useful for both rendering and other computational purposes.
[0032] Where an embodiment provides for preserving just one copy of the object to render, but with a highly variable degree of LOD, the rendering application benefits from a reduction of overall memory consumption. Further, animated point cloud objects can render variable LOD with low computing cost. However, the primary benefit is the ability to render extensive scenes with very large numbers of PC objects at completely scalable LOD in real time, with only a tiny overhead. In many cases, as described here, this can be as short as calculating the LOD index during rendering for each object. The computing device can also precompute a LOD mapping table to improve that rendering time. No memory need be wasted storing multiple copies at varying fixed LODs, nor is much computing time spent selecting the list to render. Polygonal mesh rendering systems cannot benefit from such a system, as the mesh needs to be compressed or merged at strategic points to approximate the original object. This takes advantage of the linearity of detail in PC objects when sorted or pre-calculated according a uniform attribute rule, such as surface density or barycenter averaging.
[0033] LOD Selection
[0034] During the rendering process, a level of detail is determined for each object within the viewing frustum. Distance to viewer may be taken to account such that a normalized LOD is calculated by dividing the distance to object by the LOD constant for that object. A maximum and minimum range to object can be selected, and normalized to the maximum and minimum point cloud. Cost may be used to preserve scene rendering speed—any level of detail can be specified and rendered at a known cost, CR=C*(LOD*SF)*PCC from a complete minimum detail (a single point or a constant minimum set C) to maximum detail (the entire point cloud list), or any level in between by iterating the render list until the desired detail level is reached. In this context, CR is the rendering cost, C is the constant invariant point set, LOD represents the selected level of detail, SF represents the scaling factor of points per LOD unit, and PCC is the constant cost of rendering a single cloud point. One example selection of the level of detail can be obtained by dividing the distance from the PCO to the viewing position by the normalized available maximum detail level (i.e. point density). This provides for dynamic LOD: as an object travels from far to near the viewing position, the LOD scales with the position of the object.
[0035] Object Tree Management
[0036] When performing complex rendering, object merging and animation are considerations. Rendering methods for PCLs vary greatly—octrees are a common storage method of PCL data by rendering systems. PCLs sorted using the dynamic method described here may be inserted as a node in an octree, or PCLs may be clustered into sectors, or another rendering method may be used. In general, the methodology for rendering the pre-ordered list at a given LOD is simple: the LOD is computed during the scene (see above, LOD selection), and then each object within the viewing frustum is rendered. The PCL list is rendered, atom by atom, beginning at the head of the list until the LOD index is reached. The LOD index is the array or list item number that is represented by the normalized LOD value selected during LOD selection. This provides for a known linear compute time of a definite cost. To preserve back-facing and hidden object clouds, one embodiment allows for attribution of point cloud elements during the precalculation process, such as with vectors or feature attributes related to the object position, shape or other features. This data is applied over the list via an attribute defined during the precalculation of the PCL ordering, and attributes of particular points may be assigned using identifiers. For example, all points on the hidden side of the cube may be marked with a vector indicating the estimated normal of the cube face to the viewer for backface culling. There are no limits to the number of attributes that one can apply to the nodes, provided that the reordered PCL preserves the attributes in the same way it preserves the level of detail constraints and properties.
[0037] Computation Scaling
[0038] PCL rendering provides for computational scaling, as LOD can be varied and cost computed to maintain frame rates, or to maintain total number of objects. Further, PCLs are eligible for implementation on polygon-based graphics systems, thus calculating the total polygon load is useful. For voxel-based implementations, LOD is still useful for reducing the total number of voxels to render at a distance where individual voxels are near-impossible to discern. Thus, one embodiment allows for computational scaling and estimation of cost to render for selecting ideal detail levels suited to a particular hardware platform or application configuration.
[0039] Exemplary Computer Environments
[0040] FIG. 1 is intended to illustrate a computing system environment for an embodiment of the invention. Although not required, embodiments of the invention will be described in the general context of computer-executable instructions, such as program modules or applications, being executed by one or more computers, such as client workstations, servers or other devices. Generally, applications include routines, programs, objects, components, data structures and the like that perform particular tasks or implement particular abstract data types. Typically, the functionality of the applications may be combined or distributed as desired in various embodiments. Moreover, those skilled in the art will appreciate that the invention may be practiced with other computer system configurations. Other well-known computing systems, environments, and/or configurations that may be suitable for use with embodiments of the invention include, but are not limited to, personal computers (PCs), server computers, hand-held, slate, mobile or laptop devices, multi-processor systems, microprocessor-based systems, programmable consumer electronics, network PCs, minicomputers, mainframe computers, gaming platforms and the like. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network or other data transmission medium. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.
[0041] FIG. 1 illustrates an example of a suitable computing system environment 100 in which an embodiment of the invention may be implemented. The computing system environment 100 is only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality of the invention. For example, graphics application programming interfaces may be useful in a wide range of platforms. Neither should the computing environment 100 be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary operating environment 100 .
[0042] In FIG. 1 , an exemplary system for implementing an embodiment of the invention includes a general purpose computing device in the form of a computer device 100 . Components of computer 100 may include, but are not limited to, a processing unit 105 , a system memory 110 , and a system bus 108 that couples various system components including the system memory to the processing unit 105 . The system bus 108 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include (HT) Hyper Transport, Industry Standard Architecture (ISA), Micro Channel Architecture (MCA), Enhanced ISA (EISA), QuickPath Interconnect (QPI), and Peripheral Component Interconnect [Enhanced] (PCI[e]).
[0043] Computing device 100 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer 100 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise tangible computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CDROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by computer 100 . Communication media typically embodies computer readable instructions, data structures, program modules or other data. While communication media includes non-ephemeral buffers and other temporary digital storage used for communications, it does not include transient signals in as far as they are ephemeral over a physical medium (wired 190 or wireless 195 , 200 ) during transmission between devices. Combinations of any of the above should also be included within the scope of computer readable media.
[0044] The system memory 110 includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory 110 (ROM) and random access memory 110 (RAM). The processing unit 110 and bus 108 allow for transfer of information between elements within computer 110 , such as during start-up, typically stored in ROM 110 . RAM 110 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 105 . By way of example, and not limitation, FIG. 1 illustrates operating system 170 , application programs 175 , other program modules 180 , and program data 185 .
[0045] The computer 100 may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only, FIG. 1 illustrates a drive 120 that reads from or writes to non-removable, nonvolatile media including NVRAM or magnetic disc, a magnetic disk drive 140 that reads from or writes to a removable, nonvolatile disk, optical disk, solid state disk, or other NVRAM. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, Blu-Ray disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 120 is typically connected to the system bus 108 through a non-removable memory interface such as interface 115 , or removably connected to the system bus 108 by a removable memory interface, such as interface 135 .
[0046] The drives and their associated computer storage media discussed above and illustrated in FIG. 1 , provide storage of computer readable instructions, data structures, program modules and other data for the computer 100 . In FIG. 1 , for example, disk drive 120 is illustrated as storing operating system 170 , application programs 175 , other program modules 180 , and program data 185 . Note that these components can either be the same as or different from operating system 170 , application programs 175 , other program modules 180 , and program data 185 . Operating system 170 , application programs 175 , other program modules 180 , and program data 185 are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into the computer 100 through input devices such as a keyboard 210 and pointing device 210 , commonly referred to as a mouse, trackball or touch pad. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, depth or motion sensor (such as Microsoft Kinect™), scanner, or the like. These and other input devices are often connected to the processing unit 105 through the system bus 108 , but may be connected by other interface and bus structures, such as a parallel port, game port, Firewire™ or a universal serial bus (USB). A monitor 210 or other type of display device is also connected to the system bus 108 via an interface, such as a video interface 145 . In addition to the monitor, computers may also include other peripheral output devices such as speakers and printer, which may be connected through an output peripheral interface 155 .
[0047] The computer 100 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 215 . The remote computer 215 may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer 100 . When used in a LAN networking environment, the computer 100 is connected to the LAN through a network interface 130 . When used in a WAN networking environment, the computer 100 typically establishes communications over the wired adapter 190 , wireless adapter 195 , or cellular 200 . In a networked environment, program modules depicted relative to the computer 100 , or portions thereof, may be stored in the remote 215 memory storage device ( 220 or 225 ).
[0048] Virtual services and data 160 may be provided to the bus 108 , CPU 105 and memory 110 via remote interface 215 . An example of such virtual services may include a remote server 225 or cloud storage 220 . In practical application, virtual services are mounted via the network interface 125 to the physical networking adapters 190 , 195 and 220 .
[0049] Applications 170 accessing 3D rendering services via the graphics interface 145 communicate with the GPU 150 to produce 3D visual display imagery 210 . The primary APIs for rendering 145 typically include 2D and 3D libraries to allow easy access to applications 170 . Alternatively, imagery from the GPU 150 may be redirected to local memory 110 , or to networked devices 130 or cloud services 220 .
[0050] FIG. 2 illustrates application 170 access to the software interface 145 and hardware GPU 150 . In particular, 3D application 200 lies on the software/CPU side of the CPU/GPU boundary 240 . 3D applications 200 compute 3d geometry and make calls to graphical APIs 225 and 230 . If the 3D application 200 is processing polygonal data 205 , then the rendering path is via the 3D polygon library 215 , which calls the Polygonal 3D API 225 . An example of said library and API are GLUT and OpenGL, respectively, or XNA and DirectX. Conversely, if the 3D Application 200 is processing Point Cloud data 210 , a Point Cloud library 220 is called, which ultimately calls the Point Cloud 3D API 230 .
[0051] The Point Cloud 3D Library 220 may transform point cloud data into polygonal form for rendering on a traditional Polygonal 3D Library 225 , however modern GPUs are pushing the CPU/GPU Boundary 240 “north” into object space. For example, a Point Cloud management library accepting point cloud data 210 may transform and make calls to the Polygonal 3D API 225 via, for example, tessellation. The role of both the Polygonal 3D API 225 and the Point Cloud 3D API 230 pushes data across CPU/GPU Boundary 240 for rasterization via the GPU instruction stream 280 . The GPU is responsible for moving the 3D object information in object space into image space.
[0052] The GPU Front End 250 receives GPU instructions 280 from the rendering APIs ( 225 , 230 ) for processing into a rasterizable format. Primitive assembly 255 involves transforming the 3D data into transformed vertex geometry suitable for rasterization. Rasterization 260 on the GPU produces a stream of fragments from the primitives assembled 255 in the GPU pipeline. The rasterizer 260 executes rasterization operations 265 to write display data into the Frame Buffer 270 , a process known as “compositing” of the fragments into an image. Modern rasterizers 260 allow for rasterization programs to customize fragment rendering. The Frame Buffer 270 ultimately holds the composited display image when rasterization 260 is complete. Vertex programs and shader programs may join the pipeline anywhere from the GPU front end 250 to the rasterization process 260 to inject data.
[0053] Dynamic Level of Detail for Point Cloud Objects
[0054] FIG. 3 illustrates the process of a component for recomputing a point cloud list 310 for rendering with dynamic level of detail 345 . A raw sampling of an object into point cloud information is called a raw point cloud list (RPCL) or a raw point cloud object (RPCO). A raw point cloud object (RPCO) 310 is received 300 by the processor executing the recomputing process. The receiving 300 by the precomputing component loads the RPCL into memory in an optimally organized format, such as utilizing an indexed data structure such as a b-tree or a linear array list. This allows for high performance reorganization and insertion of new points. This receiving 300 also provides for a local copy, or a reference or pointer to the list in memory where it can be safely altered.
[0055] The data structure can be analyzed to determine the barycenter or centroid of the point cloud for future processing steps, and to determine the mandatory and minimum set of points needed to render the object. Any object a sufficient distance from an observer is a single point; thus, a single point is the smallest point set that can be used for the minimum set, however such a set should preferably represent the outline of the object in a recognizable form. For example, as FIG. 5A , a cube would in the minimal form can include just 8 corner points.
[0056] When the entire raw point data is available, the processor determines the desired constraining attributes 315 of the recomputing operation of FIG. 3 . Such constraints change the character of the ordered point cloud object 345 that is produced from the recomputing. When the precomputing component resamples or reorders, the point cloud object should satisfy certain key attributes that guide the recomputing of FIG. 3 . Examples of possible attributes for recomputing include: (1) preservation of the barycenter (either under uniform or non-uniform object density), (2) preservation of the geometric centroid, (3) preservation of 2D facial surface density, (4) preservation of a volumetric density in one or more volumetric spaces, and (5) symmetry across planar partitions. Attributes are likely to vary given the nature of point data, and so the attributes are preserved within an acceptable error bound during the verification step 330 . This error bound varies from application to application, and should be tuned to minimize visual defects.
[0057] One preferable attribute for preservation is maintenance of the 3D centroid or barycenter of the PCO when iterating from the head of the list to the tail of the list. Such an ordering preserves the point cloud object integrity in a manner during variable LOD rendering. A second attribute of importance is that of maintaining approximate point density per surface when rendering down the list (again, error tolerance can be selected). For example, a cube has six faces, of which the average point density per face or per volume can be maintained by adding a single point to each face of the cube before adding a second point to any face. The first point would typically appear in the center of each face of the cube, however error tolerances or a resistance to resampling would allow for the closest point to center to be selected instead. Given that most PC objects will not be symmetrical, the cube is less suited for more advanced attributes—they can include items such as collision spaces, color density, and clustering. Other attributes across all PCLs in the rendering engine can be preserved as well—for example, objects can be assigned a certain number of points or atoms such that LOD values are normalized at maximum detail. This operation may require sampling the surfaces of the object and adding new points, or removing points from apparent surfaces having an excess of points.
[0058] Once the constraints are determined 315 , the process of ordering the PCO data starts 320 . The ordering process selects an unordered point from the point cloud list 325 for the purpose of attempting to constrain the attribute within an acceptable bound (verified in step 330 ). The selection of the PCO point 325 is tuned to produce data that will attempt to satisfy the verification step 330 . The ordering may be performed with the intent of producing a result approximate to preserving the attribute, but then allow for a correction or interpolation of the point to more fully satisfy the constraint at step 335 . One method of constraining the centroid or barycenter attribute is to select a point from the remaining point cloud list that is symmetrically opposite the most recently ordered point with regard to a plane that passes through the barycenter. Similarly, selecting a point that is approximately equidistant to the desired barycenter and also lying on a parallel to the vector of the prior point and the barycenter, as the most recently ordered point will preserve the attribute. See FIG. 6 .
[0059] If the verification step 330 is successful, then no interpolation or correction is necessary 335 , and thus the next point in the PCO data is processed 338 , as not all of the PCO data will be ordered for preservation of the selected attribute from step 315 . The procedure begins again at 325 for each subsequent remaining point.
[0060] FIG. 4 is a block diagram illustrating a technique of rendering an pre-ordered point cloud list in accordance with an embodiment of the invention. The receiving of a PCO vertex list presumes the existence of a prior precomputed LOD PCO in accordance with FIG. 3 , or another embodiment producing or providing a PCO LOD-compliant list, enabling dynamic level of detail. Receiving can include either (1) moving the list into memory, or (2) simply re-using an existing list in cache or main memory via pointer or array. After receiving the list 400 , a determination is made as to the LOD factor 410 based on a variety of scene information, but at least including the distance from the camera to the object. An embodiment can include factors such as the presence of multiple objects in the line of sight, occlusion of the object, and total objects in the scene. One embodiment calculates the LOD factor as the division of the length of the vector from the camera to the outermost point of the primary object in view, by the length of the furthest distance where a single PCO point is visible. This distance ratio is then multiplied by a scaling constant for the computational complexity of the scene.
[0061] After the LOD factor is determined 410 , the LOD index is computed 420 from the LOD factor. In one embodiment, the LOD factor is normalized to the vector space of the LOD PCO list and multiplied by the maximum length of the LOD PCO list. The LOD index 420 will vary from frame to frame during the rendering process as the camera is rotated, translated, scaled and applied under a potentially changing perspective matrix. Scene objects can enter and leave the view, requiring a recalculation of the LOD factor 420 . Other considerations in alternative embodiments can include the processor and GPU utilization levels, the frame rate, and changes to application rendering requirements. The LOD index will typically be constrained from 1 to N, where 1 is the first element of the PCO LOD list, and N is the final element.
[0062] When the rendering system is ready to send vertices to the graphics pipeline, a start instruction may be issued 425 . In the context of using rendering platform such as, for example OpenGL™, the beginning of the vertex list is represented by the glBegin( ) call. The PCO list is iterated 430 , 440 , 450 according to the points in the reordered vertex list. This process involves advancing the current index to the next vertex in the list 430 , sending the vertex to the rendering API 440 , and checking if the iteration is complete via a simple less than comparison 450 . If the current index equals the LOD index 450 , rendering this PCO is complete for this frame. Upon completion, an instruction is sent to the rendering system to complete the PCO vertex list 460 . In the context of using a classic rendering platform on, for example OpenGL™, the end of the vertex list is represented by the glEnd( ) call. In one embodiment, the rendering loop 410 through 460 is repeated as necessary to render multiple frames.
[0063] FIG. 5A through FIG. 5E illustrate a precomputed mid-point selection dynamic level of detail for a cube object under a regular viewing transform with random points-to-face distribution while maintaining an average barycenter, thus demonstrating an example of how a variable level of detail and variable level of detail index N produce increased visual quality. In FIGS. 5A through 5E , P1-P8 are points 510 and edges 505 representing the object volume on which the point cloud data is demonstrated for a simple cube. The cube geometry of points and edges is shown in the figure to provide a framework for understanding the point cloud data rendered on the surface of the cube. In a practical application, neither the vertices, edges, nor back-facing polygons would be shown—here the hidden surfaces are transparent and polygonal framework are revealed to further show all points of the PCO and the illustrative framework.
[0064] FIG. 5A illustrates rendering a point cloud object leveraging dynamic level of detail, with no cloud points rendered.
[0065] FIG. 5B illustrates rendering a point cloud object leveraging dynamic level of detail, where the level of detail for this particular application is low (N=58).
[0066] FIG. 5C illustrates rendering a point cloud object leveraging dynamic level of detail, where the level of detail is moderate (N=551).
[0067] FIG. 5D illustrates rendering a point cloud object leveraging dynamic level of detail, where the level of detail is high (N=1558).
[0068] FIG. 5E illustrates rendering a point cloud object leveraging dynamic level of detail, where the level of detail for this particular application is maximum (N=2100).
[0069] FIG. 6A illustrates the two dimensional determination of the centroid or barycenter of an object in accordance with an embodiment of the invention. In this figure, vertices 600 have a centroid located at 610 . The centroid for a simple triangle is calculated by bisecting the edges connecting the vertices 600 . The midpoints of these edges 605 are used to connect each vertex 600 to an edge, the intersection of all three leading to the centroid 610 . For objects where the massive body has uniform density, the barycenter will be located at the centroid, and thus this illustration applies to both scenarios.
[0070] FIG. 6B illustrates the three dimensional determination of the barycenter of an object in accordance with an embodiment of the invention. This figure expands FIG. 6A into three dimensions, and illustrates the property of the centroid 630 or barycenter for three dimension vertices 620 . The centroid or barycenter have desirable properties for purposes of preserving surface density of PCOs, in particular that preserving the average centroid or barycenter where the points are located on the surface of the object produces a uniform surface density distribution and thus precomputed ordering for a PCO. Such a distribution function is applied in FIGS. 5A through 5E . Note that for simple objects such as primary symmetrical shapes including cones, spheres, cubes, point density can be desirably maintained. However, for complex objects such as hyperextended cylinders and bunny rabbits, seeking a uniform density is easily encompassed with alternatives such as a simple algorithm such as the centroid partitioned over the object space. For example, one such algorithm is to divide the PCO volume into a voxel map (such as a 3×3×3 cube having 27 partitioned volumes), and apply the regular 3D centroid algorithm within each voxel volume similar to the cube in FIG. 6B , iterating each volume once per selection of list points. In one embodiment, optimizing the iteration of volumes can occur by selecting the outermost volumes at furthest distance from each other. Alternatively, another embodiment selects the next volume at random, choosing each containing PCO data once per cycle.
[0071] The various techniques described herein may be implemented with hardware or software or, where appropriate, with a combination of both. Thus, the methods and apparatus of the present invention, or certain aspects or portions thereof, may take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, solid state/flash drives, CD-ROMs, hard drives, or any other machine-readable storage medium, wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. In the case of program code execution on programmable computers, the computer will generally include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. One or more programs are preferably implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language, and combined with hardware implementations.
[0072] The methods and apparatus of the present invention may also be embodied in the form of program code that is transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via any other form of transmission, wherein, when the program code is received and loaded into and executed by a machine, such as an EPROM, a gate array, a programmable logic device (PLD), a client computer, a video recorder or the like, the machine becomes an apparatus for practicing the invention. When implemented on a general-purpose processor, the program code combines with the processor to provide an apparatus that operates to perform the indexing functionality of the present invention. For example, the storage techniques used in connection with the present invention may invariably be a combination of hardware and software.
[0073] While the present invention has been described in connection with the embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. For example, while exemplary embodiments of the invention are described in the context of graphics data in a computing device with a general operating system, one skilled in the art will recognize that the present invention is not limited to PC devices and that a 3D graphics API may apply to any computing device, such as a gaming console, handheld computer (e.g. mobile phone, slate, tablet, laptop), portable computer, etc., whether wired or wireless, and may be applied to any number of such computing devices connected via a communications network, and interacting across the network. For example, distributed point cloud rendering may occur over the cloud, and precomputing may occur at any time prior to rendering.
[0074] Furthermore, it should be emphasized that a variety of computer platforms, including handheld device operating systems and other application specific operating systems are contemplated, especially as the number of wireless networked devices continues to proliferate. Therefore, the present invention is not limited to any single embodiment, but rather construed in breadth and scope in accordance with the appended claims. What has been described above includes examples of the disclosed and claimed subject matter. It is, of course, not possible to describe every conceivable combination of components and/or methodologies, but one of ordinary skill in the art may recognize that many further combinations and permutations are possible. Accordingly, the claimed subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
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Rendering real-time three-dimensional computer models is a resource-intensive task, and even more so for point cloud objects. Level of detail is traditionally performed using a small number of fixed-size independent models. A new system is presented of rendering point cloud objects with efficient dynamic level of detail. Several novel point cloud dynamic level of detail techniques are presented that are fairly simple to implement and significantly more efficient in terms of managing rendering load, data reduction, and memory consumption. The novel point cloud dynamic level of detail techniques can be employed to optimize or otherwise improve the rendering efficiency of rendering point cloud objects.
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This invention relates to natural language data processing, and in particular to a method and system for the retrieval of natural language data. This invention is related to U.S. patent application Ser. Nos. 08/148,688 filed on Nov. 5, 1993,which is incorporated by reference which issued as U.S. Pat. No. 5,576,954 on Nov. 19, 1996. This invention was developed with grant funding provided in part by NASA KSC Cooperative Agreement NCC 10-003 Project 2, for use with: (1) NASA Kennedy Space Center Public Affairs; (2) NASA KSC Smart O & M Manuals on Compact Disk Project; and (3) NASA KSC Materials Science Laboratory.
This invention relates to natural language data processing, and in particular to a method and system for the retrieval of natural language data. This invention is related to U.S. patent application Ser. Nos. 08/148,688 filed on Nov. 5, 1993,which is incorporated by reference which issued as U.S. Pat. No. 5,576,954 on Nov. 19, 1996. This invention was developed with grant funding provided in part by NASA KSC Cooperative Agreement NCC 10-003 Project 2, for use with: (1) NASA Kennedy Space Center Public Affairs; (2) NASA KSC Smart O & M Manuals on Compact Disk Project; and (3) NASA KSC Materials Science Laboratory.
BACKGROUND AND PRIOR ART
Locating information using large amounts of natural language documents(referred to often as text data) is an important problem. Current commercial text retrieval systems generally focus on the use of keywords to search for information. These systems typically use a Boolean combination of keywords supplied by the user to retrieve documents. See column 1 for example of U.S. Pat. No. 4,849,898, which is incorporated by reference. In general, the retrieved documents are not ranked in any order of importance, so every retrieved document must be examined by the user. This is a serious shortcoming when large collections of documents need to be searched. For example, some data base searchers start reviewing displayed documents by going through some fifty or more documents to find those most applicable.
Statistically based text retrieval systems generally rank retrieved documents according to their statistical similarity to a user's search request(referred to often as the query). Statistically based systems provide advantages over traditional Boolean retrieval methods, especially for users of such systems, mainly because they allow for natural language input.
A secondary problem exists with the Boolean systems since they require that the user artificially create semantic search terms every time a search is conducted. This is a burdensome task to create a satisfactory query. Often the user will have to redo the query more than once. The time spent on this task is quite burdensome and would include expensive on-line search time to stay on the commercial data base.
Using a list of words to represent the content of documents is a technique that also has problems of it's own. In this technique, the fact that words are ambiguous can cause documents to be retrieved that are not relevant to the search query. Further, relevant documents can exist that do not use the same words as those provided in the query. Using semantics addresses these concerns and can improve retrieval performance. Prior art has focussed on processes for disambiguation. In these processes, the various meanings of words(also referred to as senses) are pruned(reduced) with the hope that the remaining meanings of words will be the correct one. An example of well known pruning processes is U.S. Pat. No. 5,056,021 which is incorporated by reference.
However, the pruning processes used in disambiguation cause inherent problems of their own. For example, the correct common meaning may not be selected in these processes. Further, the problems become worse when two separate sequences of words are compared to each other to determine the similarity between the two. If each sequence is disambiguated, the correct common meaning between the two may get eliminated.
The inventor of the subject invention has used semantics to avoid the disambiguation problem. See U.S. patent application Ser. Nos. 08/148,688 filed on Nov. 5, 1993 which issued as U.S. Pat. No. 5,576,954 on Nov. 19, 1996. For semantics, the various meanings of words are not pruned but combined with the various meanings of other words and the statistically common meanings for small groups of words yield the correct common meaning for those words. This approach has been shown to improve the statistical ranking of retrieved information. In the semantic approach, the prunning process for common meaning is replaced by a statistical determination of common meaning. Crucial to this approach is the fact that retrieval documents must be small.
Relevance feedback has sometimes been used to improve statistical ranking. For relevance feedback, the judgements of the user concerning viewed information are used to automatically modify the search for more information. However, in relevance feedback, conventional IR(Information Retrieval) systems have a limited recall. G. Salton, Automatic Information Organization and Retrieval, McGraw-Hill, 1968. This limited recall causes only a few relevant documents are retrieved in response to user queries if the search process is based solely on the initial query. This limited recall indicates a need to modify (or reformulate) the initial query in order to improve performance. During this reformulation, it is customary to have to search the relevant documents iteratively as a sequence of partial search operations. The results of earlier searches can be used as feedback information to improve the results of later searches. One possible way to do this is to ask the user to make a relevance decision on a certain number of retrieved documents. Then this relevance information can be manually used to construct an improved query formulation and recalculate the similarities between documents and query in order to rank them. This process is known as relevance feedback.
A basic assumption behind relevance feedback is that, for a given query, documents relevant to it should resemble each other in a sense that they have reasonably similar keyword content. This implies that if a retrieved document is identified as relevant, then the initial query can be modified to increase its similarity to such a relevant document. As a result of this reformulation, it is expected that more of the relevant documents and fewer of the nonrelevant documents will be extracted. The automatic construction of an improved query is actually straightforward, but it does increase the complexity of the user interface and the use of the retrieval system, and it can slow down query response time. Essentially, document information viewed as relevant to a query can be used to modify the weights of terms and semantic categories in the original query. A modification can also be made using documents viewed as not relevant to a query.
The main problems with using relevance feedback are many. First, the original query becomes very large whenever all the words in a viewed relevant document are added to the original query. Secondly, it takes a long time to read large documents and decide if they are relevant or not. Another problem is that often only part of a large document is actually relevant. Other patents have tried to address this problem. See U.S. Pat. No. 5,297,027 to Morimoto et al.
The inventor is not aware of any prior art that combines statistical ranking, semantics, relevance feedback and using sentences(or clauses) as documents when queries are expressed in natural language in order to be able to search for and retrieve relevant documents.
SUMMARY OF THE INVENTION
The first objective of the present invention is to provide a natural language retrieval system which combines statistical ranking, semantics, relevance feedback and using sentences(or clauses) as documents when using natural language queries in order to be able to search for and retrieve relevant documents.
The second object of this invention is to provide an automated document retrieval system that minimizes the reading efforts of the user.
The third object of this invention is to provide an automated document retrieval system that minimizes the need for highlighting relevant words on a screenful of text in order to be able to indicate relevant information from a query.
The preferred method of the invention uses statistical ranking and the concept of semantics as shown in U.S. patent application Ser. Nos. 08/148,688 filed on Nov. 5, 1993 which issued as U.S. Pat. No. 5,576,954 on Nov. 19, 1996, in order to rank relevant documents retrieved for a user's original query. After submitting a query, the user then reads one or more of the topmost documents in the ranked list of documents produced for the query. Since each document is very small (a clause, or a sentence at most), it is very easy for the user to quickly indicate if the document is relevant or not relevant to the original query. For each document flagged as relevant or not relevant, an automatic modification is made to the original query to essentially increase or decrease the importance of words. The new query is used to create another ranked list of documents. The feedback process repeats until the user stops the process.
In the subject invention, semantics helps to push relevant documents upward in a statistically ranked list. Relevance feedback helps the user automatically identify alterative words useful for expressing the query. The effort displayed by the user is minimal since the user views only small mounts of text and makes only a single judgement call on whether the small piece of text is relevant or not relevant for each small mount of text.
The invention can be applied to tasks such as retrieving documents relevant to a search request(sometimes referred to as archival retrieval), filtering documents which are relevant to a search request(sometimes referred to as routing) and answering questions from general information data bases.
Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment which is illustrated schematically in the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 illustrates the preferred embodiment of the invention.
FIG. 2 illustrates the procedure used in patent application with Ser. No. 08/148,688 (filed on Nov. 5, 1993 which issued as U.S. Pat. No. 5,576,954 on Nov. 19, 1996) to determine a number to indicate the relevance or similarity of a document to a query.
FIG. 3 illustrates an example of an original user query and a collection of eight documents.
FIG. 4 is a list of words considered too general to have any value as a keyword, or as a word having any useful semantic value.
FIG. 5 is a list of words used in the original query of FIG. 3; this list becomes Query Word List in Step 100 of FIG. 1.
FIG. 6 provides the list of words used in each of the eight documents of FIG. 3.
FIG. 7 is a list of statistical data for all the words in the eight documents of FIG. 3; the information shown is a count of the number of documents containing each word, and the IDF of each word.
FIG. 8 reveals semantic information about each word used in the original query in FIG. 3; for each word listed in FIG. 5, this figure shows a count of the semantic categories triggered by the word, along with a list of the numeric codes for those categories. This information comes for Roget's International Thesaurus (5th Edition), edited by Robert L. Chapman, HarperCollins Publishers, 1992.
FIG. 9a-9e reveal semantic information about each word used in the collection of eight documents in FIG. 3; for each word listed in FIG. 6, this figure show a count of the semantic categories triggered by the word, along with a list of the numeric codes for those categories. This information comes from Roget's International Thesaurus (5th Edition), edited by Robert L. Chapman, HarperCollins Publishers, 1992.
FIG. 10 provides the Document List of DocIds created in Step 200 of FIG. 1 for the example of FIG. 3.
FIG. 11 is a list of the eight documents in the example of FIG. 3 ranked in order of their relevance or similarity (SIM value) to the words used in the original query of FIG. 3 and shown in FIG. 5; both the DocId and the SIM value are shown as a pair in this list. This list is a sorted Relevancy List created at Step 900 in FIG. 1.
FIG. 12 is a list of words in a second query built from the original query after removing the words found in Document 5 (only the word "travel" was removed). This list is created by Step 1300 in FIG. 1.
FIG. 13 is a list of seven documents in the example of FIG. 3 (Document 5 has been removed) ranked in order of their relevance or similarity (SIM value) to the words of the second query of FIG. 12; both the DocID and the SIM value are shown as a pair in this list. This list is a sorted Relevancy List created at Step 900 in FIG. 1.
FIG. 14 is a list of words in a third query built by adding words found in Document 4 to the words of the second query of FIG. 12; this list is created by Step 1200 in FIG. 1.
FIG. 15 is a list of six documents in the example of FIG. 3 (Document 5 and Document 4 have been removed) ranked in order of their relevance or similarity (SIM value) to the words of the third query of FIG. 14; both the DocId and the SIM value are shown as a pair in this list. This list is a sorted Relevancy List created by Step 900 in FIG. 1. The top document on this list (Document 2) provides the answer to the original query of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Before explaining the disclosed embodiment of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
A prototype of the inventor's process has been successfully used at the NASA KSC Public Affairs Office. The performance of the prototype was measured by a count of the number of documents one must read in order to find an answer to a natural language question. In some queries, a noticeable semantic improvement has been observed. For example, if only keywords are used for the query "How fast does the orbiter travel on orbit?" then 17 retrieved paragraphs must be read to find the answer to the query. But if semantic information is used in conjunction with key words then only 4 retrieved paragraphs need to be read to find the answer to the query. Thus, the prototype enabled a searcher to find the answer to their query by a substantial reduction of the number of documents that must be mad.
Reference will now be made in detail to the present preferred embodiment of the invention as illustrated in the accompanying drawings.
The present preferred embodiment is demonstrated using an environment where a user's original query is a simple question and the user is searching for an answer to the question. During the search, we expect the user to see relevant and non-relevant documents. The user is expected to continue until a document answering the question is read, or until there are no more documents left to read.
The detailed description refers to acronyms and terminology that is described in the following chart.
______________________________________Terminology______________________________________SIM for a query A number which measures the relevance of aand a document document to a query.qword A word in the list of words used in a query.cat A semantic category code.qp The probability a qword triggers a cat.dword A word in the list of words used in a document.dp The probability a dword triggers a cat.DocId The identifier for a document, the document number.N Total number of documents.NDOCS The number of documents a word is in.for a wordIDF The inverse document frequency which isfor a word defined here to be log.sub.2 (N/NDOCS for the word).Document List of words used in a document. FIG. 6Word List shows eight of these lists.Query List of words used in a query.Word ListDocument List List of DocIds.Relevancy List List of DocId, SIM pairs.______________________________________
Statistical Ranking with Semantics
FIG. 2 illustrates the procedure used in U.S. patent application Ser. No. 08/148,688 (filed on Nov. 5, 1993 which issued as U.S. Pat. No. 5,576,954 on Nov. 19, 1996) to determine a number to indicate the relevance or similarity of a document to a query. The procedure is based on the existence of a semantic lexicon. For a given word, the semantic lexicon indicates all the senses (different meanings) of a word. Roget's International Thesaurus (5th Edition), edited by Robert L. Chapman, HarperCollins Publishers, 1992 can be used as a semantic lexicon. The procedure illustrated in FIG. 2 also uses a statistical similarity calculation.
To illustrate, FIG. 3 provides an original user query (a question) and a collection of eight documents, where each document is a sentence and has a DocId which is an integer number. Notice that Document 2 explicitly answers the user query.
In statistical systems it is common to have a list of words which can be ignored because they are relatively useless as keywords. FIG. 4 provides a list of words not used for this example. Using the list of words not used, the example of FIG. 3 can be transformed into the words used in the original query of FIG. 5 and the words used in each of the eight documents of FIG. 6.
FIG. 7 provides a list of statistical data for the words used in all of the eight documents, in alphabetical order. The number of documents that each word is in is shown in the second column of the table. This is called NDOCS for a word. The third column of the table in FIG. 7 indicates a measure of the importance of each word.
The formula used for calculating the importance of a word is a statistical formula. A good one to use for this example is the inverse document frequency (IDF) formula:
IDF of a word=log.sub.2 (N/NDOCS for the word)
where N is the total number of documents (8) and NDOCS is the number of documents a word is in. For example, since "orbit" is in 4 documents,
IDF for orbit=log.sub.2 (8/4)=log.sub.2 (2)=1
and since "increase" is in one document,
IDF for increase=log.sub.2 (8/1)=log.sub.2 (8)=3.
These IDF numbers are recorded in the third column of FIG. 7. It is clear that words which are in many documents are less important (as search words) than words which are in only a few documents. FIG. 8 provides the semantics of the words in the original query for each word used in the original query (FIG. 5), the second column shows the number of senses (meanings) the word has in Roget's Thesaurus, and the third column lists the numeric codes for those different meanings.
FIG. 9 provides the semantics of the words used in the eight documents. For each word used in the eight documents (FIG. 7), the second column shows the number of senses (meanings) the word has in Roget's Thesaurus, and the third column lists the numeric codes for those different meanings.
Notice that all but one of the words used in the query are used in the eight documents. The word "fast" does not appear in the eight documents.
For this example, a semantic category will be a "large category" in Roget's Thesaurus. There are 1073 large categories. The number of smaller categories will be used to determine a probability for a specific large category. For example, consider the word "fast", which triggers category "174.15" and category "174.17"; each of these is in the large category "174". So, the word "fast" triggers category "174" with a probability of 2/15 since 15 is the number of smaller categories triggered by the word "fast."
Also in this example, the weight of a word in a document will be the frequency of the word in the document multiplied by the word's IDF value. In the example, all frequencies turn out to be 1, so the weight of a word in a document becomes the word's IDF value.
The calculation of a SIM value for a query and a document can now be explained by reference to the Similarity Procedure in FIG. 2 and a small sample calculation. Consider the words used in the original query of FIG. 5 and the words used in Document 4 of FIG. 6. These two lists are called the Query Word List and the Document Word List, and they are the inputs to the Similarity Procedure.
Step 405 sets the SIM value to zero. Step 410 sets qword to "fast". Since "fast" is not in Document 4, Step 420 causes movement to Step 430. Since "fast" does trigger semantic categories, Step 430 causes movement to Step 435 and Step 440 causes cat to be "515" and qp to be 1/15. At Step 445, there is no word in Document 4 that triggers "515" so Step 435 is executed again. Steps 435, 440, and 445 re repeatedly executed with no movement to Step 450 until category "174" is used. At Step 440, cat eventually becomes "174" and qp becomes 2/15 since there are two of "174" in the list of categories triggered by "fast". At Step 450, dword becomes "velocity" since "velocity" triggers "174". Also, dp becomes 1/3 since "velocity" triggers three separate categories.
At Step 455, notice that since "fast" is not a word in any of the documents, its IDF is not defined in FIG. 7; so, in this case, the IDF of the word "velocity" is substituted. Another possibility in this case is to substitute a very high IDF value for undefined IDF values. At Step 455, SIM is increased by
(2/15* 1) * (1/3* 1)=0.0444
so SIM now equals 0.0444.
Eventually, at Step 435, there are no more categories triggered by "fast" and this causes movement to Step 410.
At Step 410, "orbit" is the next word in the query and, at Step 415, qword now becomes "orbit". At Step 420, the fact that "orbit" is also in Document 4 causes movement to Step 425. At Step 425, SIM is increase by the weight of "orbit" in the query multiplied by the weight of "orbit" in Document 4, and this amount is
(1)*(1)=1.0000
so SIM now equals 1.0444.
At Step 430, since "orbit" also triggers semantic categories, there is movement to Step 435. Steps 435, 440, and 445 are repeatedly executed for the semantic categories triggered by "orbit". For category "245" triggered by "orbit", the word "increase" in Document 4 is also a trigger. So, when cat becomes "245" and qp becomes 1/13, Step 450 causes dword to become "increase" and dp to become 1/20. Then, at Step 455, SIM is increased by
(1/13* 1)*(1/20* 3)=0.0154
so SIM now equals 1.0598. Note that the IDF of "increase" is 3, and so the weight of "increase" in Document 4 is 3.
Notice that Step 445 does not select the word "orbit" in Document 4, since qword is "orbit" and the semantic contribution of "orbit" in Document 4 was handled earlier by Step 425. Eventually, at Step 435, there are no more categories triggered by "orbit" and this causes movement to Step 410.
At Step 410, "orbiter" is the next word in the query and at Step 415, qword now becomes "orbiter". Since "orbiter" is also in Document 4, Step 420 causes movement to Step 425. At Step 425, SIM is increased by the weight of "orbiter" in the query multiplied by the weight of "orbiter" in Document 4, and this amount is
(1)*(1)=1.0000
so SIM now equals 2.0598.
At Step 430, since "orbiter" does not trigger any semantic categories, there is movement to Step 410.
At Step 410, "travel" is the next (and last) word in the query and, at Step 415, qword now becomes "travel". Since "travel" is not in Document 4, Step 420 causes movement to Step 430. Since "travel" does trigger semantic categories, Step 430 causes movement to Step 435 and Step 440 causes cat to be "162" and qp to be 2/9 since "travel" triggers "162.1" and "162.2". At Step 445, there is no word in Document 4 that triggers "162", so Step 435 is executed again. Steps 435, 440, and 445 are repeatedly executed with no movement to Step 450 until category "172" is used, and category "177" is used.
When Step 440 causes cat to become "172" and qp to be 2/9, Step 445 causes movement to Step 450. The value of qp is 2/9 because "travel" triggers "172.2" and "172.5". At Step 450, dword becomes "velocity" and dp becomes 1/3 since "velocity" triggers "172" among three triggered separate categories. At Step 455, SIM is increased by
(2/9* 3)*(1/3* 1)=0.2222
so SIM now equals 2.2820.
When Step 440 causes cat be become "177" and qp to be 4/9, Step 445 causes movement to Step 450. The value of qp is 4/9 because "travel" triggers "177", "177.1", "177.18", and "177.21". At Step 450, dword becomes "velocity" and dp becomes 1/3. At Step 455, SIM is increased by
(4/9* 3)*(1/3* 1)=0.4444
so SIM now equals 2.7264.
Eventually, at Step 435, there are no more categories triggered by "travel" and this causes movement to Step 410. At Step 410, the procedure for calculating SIM stops because there are no more words in the query.
The final value of SIM is 2.7264 and this represents a measure of the similarity between the original query in FIG. 3 and Document 4 in FIG. 3. The DocId of 4 and the SIM value of 2.7264 are the outputs of the Similarity Procedure.
Relevance Feedback with Small Amounts of Text
FIG. 1 illustrates the preferred embodiment of the invention. The Feedback Procedure of FIG. 1 activates the Similarity Procedure of FIG. 2 many times. To illustrate, FIG. 3 provides an original user query (a question) and a collection of eight documents, where each document is a sentence and has a DocId which is an integer. Notice that Document 2 explicitly answers the user query.
This is a question/answer environment and the preferred embodiment of the invention is designed for this environment. The invention will help the user retrieve Document 2 (the answer to the user query in FIG. 3).
At Step 100, Query Word List is set to the list of four words used in the original user query and shown in FIG. 5. At Step 200, Document Word List is set to the list of eight DocIds shown in FIG. 10. At Step 300, Relevancy List is set to be empty. Eventually, Relevancy List will be a list of DocId, SIM pairs sorted by SIM value to represent a ranking of the documents based on their statistical similarity to the query.
At Step 400, DocId is set equal to the first document identifier in Document List. DocId is set to Document 1.
At Step 500, the Query Word List of FIG. 5 and the Document Word List for Document 1 in FIG. 6 are input to the Similarity Procedure of FIG. 2. The output of the Similarity Procedure is DocId of 1 and SIM of 2.0338.
At Step 600, the pair DocId of 1 and SEVI of 2.0338 is added to the Relevancy List. Since there are more DocIds to process in Document List, Step 700 causes movement to Step 800 where DocId becomes Document 2. Then Step 500 activates the Similarity Procedure, again. Steps 500, 600, 700, and 800 cause the Similarity Procedure to be activated for each DocId in Document List, along with addition of the DocIds and their SIM values as pairs in Relevancy List. Eventually, Step 700 causes movement to Step 900 where the Relevancy List is sorted on SIM value.
FIG. 11 reveals the result of Step 900 for the original user query and the eight documents of FIG. 3. Statistical keyword and semantic ranking has determined that Document 5 is the most relevant document for the original user query, Document 4 is the next most relevant document for the original query, and so on.
At Step 1000, DocId is set to Document 5 and the document
"Atlantis will travel more than half a million miles in ocean research."
is shown to the user at Step 1100 where the user must decide if the sentence is relevant, not relevant, or answers the original query. The sentence is obviously not relevant, so Step 1100 causes movement to Step 1300. At Step 1300, any word in the Document Word List for Document 5 (as shown in FIG. 6) is removed from the Query Word List of FIG. 5; the result is shown in FIG. 12 where the word "travel" has been removed. The Query Word List now has three words in it, and it becomes the automatically built second query.
At Step 1400, DocId of 5 is removed from the Document List since the user has read the document. Since there are still seven documents in Document List, Step 1500 causes movement to Step 300 where the Relevancy List is set to empty, again.
At Step 400, DocId is set equal to Document 1 again and Steps 500, 600, 700, and 800 cause the activation of the Similarity Procedure of FIG. 2 for computing the similarity of the second query to each of the remaining seven documents, along with addition of the DocIds and their SIM values in Relevancy List. Eventually, Step 700 causes movement to Step 900 where the Relevancy List is sorted on SIM value.
FIG. 13 reveals the result of Step 900 for the second query and the seven documents not read by the user. Statistical keyword and semantic ranking has determined that Document 4 is now the most relevant document.
At Step 1000, DocId is set to Document 4 and the document
"The engines are used to increase the velocity of the orbiter on orbit."
is shown to the user at Step 1100 where the user must decide if the sentence is relevant, not relevant, or answers the original query. Most people would agree that the sentence is relevant, so Step 1100 causes movement to Step 1200.
At Step 1200, the words in the Document Word List for Document 4 (as shown in FIG. 6) are added to the Query Word List for the second query of FIG. 12; the result is shown in FIG. 14 where the words "engines", "increase", and "velocity" are added. The Query Word List now has six words in it, and it becomes the automatically built third query.
At Step 1400, DocId of 4 is removed from the Document List since the user has read the document. Since there are still six documents in the Document List, Step 1500 causes movement to Step 300 where the Relevancy List is set to empty, again.
At Step 400, DocId is set equal to Document 1 again and Steps 500, 600, 700, and 800 cause the activation of the Similarity Procedure of FIG. 2 for computing the similarity of the third query to each of the remaining six documents, along with addition of the DocIds and their SIM values in Relevancy List. Eventually, Step 700 causes movement to Step 900 where the Relevancy List is sorted on SIM value.
FIG. 15 reveals the result of Step 900 for the third query and the six documents not yet read by the user. Statistical keyword and semantic ranking has determined that Document 2 is now the most relevant document.
At Step 1000, DocId is set to Document 2 and the document
"The orbiter's engines maintain a velocity on orbit of approximately 25,405 feet per second."
is shown to the user at Step 1100 where the user must decide if the sentence is relevant, not relevant, or answers the original query. Obviously, Document 2 provides the answer to the original query, so the retrieval process stops after three sentences were read.
The feedback and sentencer features are quite useful to user in saving time and enhancing the quality of the search. The feedback feature of the subject invention helps to introduce new words and gets rid of bad words. e.g. the word travel is removed from FIG. 5 and "velocity" is added in FIG. 14.
The sentencer minimizes reading time and allows the user to make their relevancy decisions very easy by just requiring the user to indicate by a key stroke whether a document is relative or not relative. In addition, the sentencer saves the user time by forcing the user to discover small "units" which are relevant or not relevant and the decision is easy.
While the preferred embodiment has been described in reference to one type of document collection, the invention can be equally applicable to all types of documents such as but not limited to patents, legal documents, medical documents, articles, journals and the like.
Further, there is no size limit to the number of documents that can be searched.
The invention can be incorporated on personal computers to search for internal files and can be applied to modem search systems accessible to DIALOG, ORBIT, and the like.
While the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.
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Search system and method for retrieving relevant documents from a text data base collection comprised of patents, medical and legal documents, journals, news stories and the like. Each small piece of text within the documents such as a sentence, phrase and semantic unit in the data base is treated as a document. Natural language queries are used to search for relevant documents from the data base. A first search query creates a selected group of documents. Each word in both the search query and in the documents are given weighted values. Combining the weighted values creates similarity values for each document which are then ranked according to their relevant importance to the search query. A user reading and passing through this ranked list checks off which documents are relevant or not. Then the system automatically causes the original search query to be updated into a second search query which can include the same words, less words or different words than the first search query. Words in the second search query can have the same or different weights compared to the first search query. The system automatically searches the text data base and creates a second group of documents, which as a minimum does not include at least one of the documents found in the first group. The second group can also be comprised of additional documents not found in the first group. The ranking of documents in the second group is different than the first ranking such that the more relevant documents are found closer to the top of the list.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the Korean Patent Application No. 10-2010-0133427 filed on Dec. 23, 2010, which are hereby incorporated by reference as if fully set forth herein.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates to a display apparatus, and more particularly, to a display apparatus which facilitates to minimize a thickness by innovatively removing a case and/or some portions of a set cover, which have been regarded as indispensible structures for the display apparatus, and simultaneously facilitates to realize a good sense of beauty in the display apparatus by a novel design.
[0004] 2. Discussion of the Related Art
[0005] Recently, various flat-type display devices, which substitutes for Cathode Ray Tube (CRT), have been actively researched and studied, for example, Liquid Crystal Display (LCD) device, Plasma Display Panel (PDP), Field Emission Display Device (FED), Light Emitting Display (LED) device, and etc. Especially, the LCD device has attracted great attentions owing to the advantageous properties such as mass production technology, simple driving means, and high picture quality.
[0006] Recent research and development are particularly being required on designs of products appealing to consumers. Consequently, efforts for minimizing the thicknesses (slimness) of LCD devices are continuously being made, and research is being conducted on a design with enhanced sense of beauty that can induce consumers to buy by appealing to consumers' sense of beauty.
[0007] In efforts for minimizing the thicknesses of LCD devices and design development for enhancing a sense of beauty that have been made to date, however, the existing elements have been applied as is, the structures of the elements have been changed simply, and thus, there are limitations in minimizing the thicknesses of the LCD devices and developing new designs of the LCD devices.
[0008] For example, a related art LCD device necessarily uses lower and upper cases to receive a liquid crystal display panel and a backlight unit therein. In addition, front and rear set covers are additionally used in the related art LCD device to manufacture a product such as a notebook computer, a monitor, a mobile device, or a television. As the lower and upper cases and the front and rear set covers for the manufactured device are inevitably used, it makes a limitation in the slimness of the display device and the advance toward the new design. Especially, the front edge parts of the liquid crystal display panel are covered with the upper case and the front set cover, whereby the liquid crystal display device is increased in its thickness. Also, the border width of the liquid crystal display device may be increased so that the difference in height of the stepped portion may cause limitations in advance toward the innovative design.
SUMMARY
[0009] Accordingly, the present invention is directed to a display apparatus that substantially obviates one or more problems due to limitations and disadvantages of the related art.
[0010] An aspect of the present invention is to provide a display apparatus which facilitates to minimize a thickness by innovatively removing a case and some portions of a set cover, which have been regarded as indispensible structures for the display apparatus, and simultaneously facilitates to realize a good sense of beauty in the display apparatus by a novel design.
[0011] Another aspect of the present invention is to provide a display apparatus which facilitates to seal a gap between a display panel and a set cover, the gap which might occur by removing case and/or portions of set cover.
[0012] Additional advantages and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0013] To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a display apparatus comprising: a set cover which has a space prepared by a sidewall; a display panel which includes lower and upper substrates bonded to each other; and a guide frame which supports the display panel, and seals a gap between a sidewall of the set cover and a lateral side of the display panel, wherein the guide frame is provided in the set cover.
[0014] At this time, the guide frame includes: a panel supporting part onto which the display panel is placed; and a sealing member which seals the gap between the sidewall of the set cover and the lateral side of the display panel, wherein the sealing member is formed in the panel supporting part.
[0015] Also, the panel supporting part and the sealing member are formed as one body by a double injection method or insert injection method.
[0016] The sealing member is formed of rubber, thermoplastic urethane, or thermoplastic elastomer.
[0017] The sidewall of the set cover and the sealing member form a front edge portion of the display panel.
[0018] The display panel includes an upper polarizing plate attached to a front surface of the upper substrate, wherein respective upper surfaces of the sidewall of the set cover, the sealing member, and the upper polarizing plate are provided at the same height along the same horizontal line.
[0019] Furthermore, the display apparatus comprises a plurality of coupling members combined with the set cover via the panel supporting part, the coupling members for combining the guide frame with the set cover.
[0020] In addition, the display apparatus comprises an adhesive member formed between the panel supporting part and the display panel, the adhesive member for placing the displaying panel onto the panel supporting part.
[0021] The display panel includes a lower polarizing plate attached to a rear surface of the lower substrate, wherein the adhesive member is formed between the panel supporting part and the lower substrate, or between the panel supporting part and the lower polarizing plate.
[0022] The set cover includes a sidewall groove which is hollowly formed from an inner sidewall.
[0023] The guide frame includes: a panel supporting part on which the display panel is placed; a first sealing member which is formed as one body with the panel supporting part, the first sealing member for sealing the gap between the sidewall of the set cover and the lateral side of the display panel; and a second sealing member which protrudes from the sidewall of the first sealing member, and is inserted into the sidewall groove of the set cover, the second sealing member for preventing foreign matters from being penetrated via a gap between the sidewall of the set cover and the first sealing member.
[0024] The first and second sealing members are formed of rubber, thermoplastic urethane, or thermoplastic elastomer.
[0025] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
[0027] FIG. 1 illustrates a display apparatus according to the first embodiment of the present invention;
[0028] FIGS. 2A to 2C illustrate various embodiments of guide frame of FIG. 1 ;
[0029] FIG. 3 illustrates a display apparatus according to the second embodiment of the present invention;
[0030] FIG. 4 illustrates a process for combining a guide frame with a set cover by the use of plurality coupling members;
[0031] FIG. 5 illustrates a display apparatus according to the third embodiment of the present invention; and
[0032] FIG. 6 is an expanded view showing ‘A’ of FIG. 5 .
DETAILED DESCRIPTION OF THE INVENTION
[0033] Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0034] Hereinafter, a display apparatus according to the present invention will be described with reference to the accompanying drawings.
[0035] FIG. 1 illustrates a display apparatus according to the first embodiment of the present invention.
[0036] Referring to FIG. 1 , the display apparatus 10 according to the first embodiment of the present invention includes a set cover 100 , a bottom cover 110 , a backlight unit 120 , a guide frame 130 , an adhesive member 140 , and a display panel 150 .
[0037] The set cover 100 is formed in a square-shaped frame structure. The set cover 100 may be formed of plastic or metal material. For enhancing the sense of beauty in the manufactured display apparatus, it is preferable that the set cover 100 be formed of the metal material.
[0038] The set cover 100 functions as a later and rear cover of the manufactured display apparatus (for example, notebook computer, monitor, or television). Also, the set cover 100 supports the bottom cover 110 and the guide frame 130 . For this, the set cover 100 includes a space 102 prepared by a sidewall, and a frame supporting part 104 formed with a stepped portion from the sidewall.
[0039] The space 102 is prepared inside of the display apparatus 10 by the sidewall. Then, the bottom cover 110 is received and supported in the space 102 of the set cover 100 .
[0040] The frame supporting part 104 is provided with the stepped portion from the sidewall, to thereby support the guide frame 130 . In this case, the frame supporting part 104 includes a frame combining part 106 to be combined with the guide frame 130 .
[0041] The bottom cover 110 is received in the space 102 of the set cover 100 , and the backlight unit 120 is received in the bottom cover 110 . Preferably, the bottom cover 110 is formed of a metal material so as to smoothly dissipate heat generated in the backlight unit 120 to the external. The bottom cover 110 may be fixed to the space 102 of the set cover 100 by the use of both-sided tape or coupling screw. Depending on the structure of the display apparatus 10 , the bottom cover 110 may be omissible.
[0042] The backlight unit 120 is received in the bottom cover 110 , wherein the backlight unit 120 emits light toward the rear of the display panel 150 . If the bottom cover 110 is omitted, the backlight unit 120 emits light toward the rear of the display panel 150 while being received in the space 102 of the set cover 100 . For this, the backlight unit 120 includes a light-guiding plate 122 , a reflective sheet 124 , and an optical member 126 .
[0043] The light-guiding plate 122 is formed having a light-incidence surface, whereby the light-guiding plate 122 guides the light, which is emitted from a light source (not shown) and is then incident on the light-incidence surface, toward the display panel 150 . At this time, the light source (not shown) may include a substrate, and a plurality of light-emitting diodes mounted on the substrate, but not necessarily. Instead of the light-emitting diodes, fluorescent lamps may be included.
[0044] The reflective sheet 124 is arranged on the rear surface of the light-guiding plate 122 , and is placed on the set cover 100 . The reflective sheet 124 reflects the incident light toward the light-guiding plate 122 .
[0045] The optical member 126 , which is provided on the light-guiding plate 122 , improves luminance property of the light advancing toward the display panel 150 from the light-guiding plate 122 . For this, the optical member 126 may include a lower diffusion sheet, at least one prism sheet, and an upper diffusion sheet.
[0046] The guide frame 130 , which is combed with the set cover 100 , supports the display panel 150 , and seals (or removes) a gap between the set cover 100 and the display panel 150 . For this, the guide frame 130 may include a panel supporting part 132 and a sealing member 134 .
[0047] The panel supporting part 132 having a predetermined shape is placed on the frame supporting part 104 of the set cover 100 . The panel supporting part 132 may be formed of a plastic material, and the panel supporting part 132 may be a compressed product or molded product by an extrusion molding (or extrusion injection) method. The panel supporting part 132 supports the rear edge of the display panel 150 .
[0048] The sealing member 134 is formed as one body with the lateral side of the panel supporting part 132 , to thereby seal the gap between the display panel 150 and the set cover 100 to be explained. At this time, an upper surface of the sealing member 134 exactly meets with the sidewall of the set cover 100 along the same vertical line without being stepped, whereby the sealing member 134 is exposed to the external while being shown as the front of the display apparatus 10 . The sealing member 134 of rubber, thermoplastic urethane, or thermoplastic elastomer may be formed as one body with the panel supporting part 132 . That is, the panel supporting part 132 and the sealing member 134 may be formed at the same time by a double injection method or insert injection method.
[0049] The sealing member 134 may be formed in various shapes by the double injection method, and may be formed as one body with the panel supporting part 132 . For example, the sealing member 134 may be vertically formed to cover a projection 132 a formed at one lateral side of the panel supporting part 132 , as shown in FIG. 2A ; or the sealing member 134 may be vertically formed to cover a projection 132 b formed on a predetermined side portion of an upper surface of the panel supporting part 132 , as shown in FIG. 2B . Also, the sealing member 134 without an additional projection may be vertically formed on a predetermined side portion of an upper surface of the panel supporting part 132 , as shown in FIG. 2C .
[0050] As shown in FIGS. 2A to 2C , the guide frame 130 may further include a frame fixing part 136 and an adhesive member guide groove 138 .
[0051] The frame fixing part 136 protrudes at a predetermined height from a rear surface of the panel supporting part 132 , and the protruding frame fixing part 136 is combined with the frame combining part 106 of the set cover 100 . Thus, the guide frame 130 is fixed into the set cover 100 by combination of the frame fixing part 136 and the frame combining part 106 . Meanwhile, the guide frame 130 may be combined with the frame supporting part 104 of the set cover 100 by the use of both-sided tape or adhesive. In this case, the frame fixing part 136 may be omitted.
[0052] The adhesive member guide groove 138 is hollowly formed with a predetermined depth from the upper surface of the panel supporting part 132 , wherein the adhesive member 140 to be explained is adhered to the adhesive member guide groove 138 . The adhesive member guide groove 138 may be omitted.
[0053] Referring once again to FIG. 1 , the adhesive member 140 is formed on the panel supporting part 132 of the guide frame 130 , to thereby adhere the display panel 150 into the guide frame 130 . In this case, if the adhesive member guide groove 138 is formed in the panel supporting part 132 , the adhesive member 140 is formed in the adhesive member guide groove 138 of the panel supporting part 132 . The adhesive member 140 may be the both-sided tape or adhesive.
[0054] The display panel 150 is placed onto the panel supporting part 132 of the guide panel 130 , wherein the display panel 150 displays a predetermined image in accordance with transmittance of light emitted from the backlight unit 120 . For this, the display panel 150 includes a lower substrate 152 , an upper substrate 154 , a lower polarizing plate 156 , and an upper polarizing plate 158 .
[0055] The lower substrate 152 includes a plurality of gate lines (not shown), a plurality of data lines (not shown), and a plurality of pixels (not shown) formed every intersection of the gate and data lines.
[0056] Each pixel includes a thin film transistor (not shown) which is connected with the gate and data lines; a pixel electrode which is connected with the thin film transistor; and a common electrode which is formed adjacent to the pixel electrode and is supplied with a common voltage. The lower substrate 150 controls the transmittance of light in the liquid crystal layer by forming an electric field corresponding to a differential voltage between the data and common voltages applied to each pixel.
[0057] The upper substrate 154 includes a color filter corresponding to each pixel of the lower substrate 152 . The upper substrate 154 is bonded to the confronting lower substrate 152 under the circumstance the liquid crystal layer is interposed between the lower and upper substrates 152 and 154 . Depending on a driving method of the liquid crystal layer, the common electrode supplied with the common voltage may be formed on the upper substrate 154 . The upper substrate 154 filters the light incident via the liquid crystal layer by the use of color filters, and emits the color-filtered light to the external, whereby colored images are displayed on the display panel 150 .
[0058] A detailed structure of each of the lower and upper substrates 152 and 154 may vary according to a driving mode of the liquid crystal layer, for example, Twisted Nematic (TN) mode, Vertical Alignment (VA) mode, In-Plane Switching (IPS) mode, Fringe Field Switching (FFS) mode, and etc., which are generally known to those skilled in the art.
[0059] The lower polarizing plate 156 is formed on a rear surface of the lower substrate 152 . The lower polarizing plate 156 polarizes the incident light, whereby the lower substrate 152 is irradiated with the light polarized by the lower polarizing plate 156 .
[0060] The upper polarizing plate 158 is attached to an upper surface of the upper substrate 154 , wherein the upper polarizing plate 158 polarizes the light incident via the upper substrate 154 , and emits the polarized light to the external. An upper surface of the upper polarizing plate 158 is provided at the same horizontal line as an upper surface of the sidewall of the set cover 100 . Also, the upper polarizing plate 158 is attached to an entire frontal surface of the upper substrate 154 so that a lateral side of the upper polarizing plate 158 is brought into contact with the sealing member 134 of the guide frame 130 , preferably.
[0061] As mentioned above, the display panel 150 may be formed of a liquid crystal display panel which displays a predetermined image in accordance with transmittance of light emitted from the backlight unit 120 , or may be formed of an organic light-emitting display panel which displays a predetermined image in accordance with a light emission of an light-emitting device.
[0062] The display panel 150 of the organic light-emitting display panel may include a lower substrate including a plurality of light-emitting cells formed every region defined by a gate line, a data line, and a power line (VDD); and an upper substrate being bonded to the lower substrate while confronting the lower substrate.
[0063] Each of the plurality of light-emitting cells on the lower substrate may include at least one switching transistor which is connected with the gate and data lines; at least one driving transistor which is connected with the switching transistor and the power line (VDD); and an light-emitting device which emits light in accordance with a current controlled by switching of the driving transistor.
[0064] The upper substrate may include an absorbent for protecting the light-emitting device from the moisture or atmosphere. The upper substrate may further include the light-emitting device which is connected with the driving transistor. In this case, the light-emitting device is removed from the lower substrate.
[0065] Meanwhile, in case of the display panel 150 of the organic light-emitting display panel, the above backlight unit 120 is removed since the organic light-emitting display panel emits light in itself.
[0066] The display panel 150 is placed onto the panel supporting part 132 of the guide frame 130 with the adhesive member 140 while being surrounded by the sealing member 134 of the guide frame 130 . At this time, the sealing member 134 functions as a buffer from the pushing force of the display panel 150 placed onto the panel supporting part 132 of the guide frame 130 . Also, the sealing member 134 seals the gap between the set cover 100 and the lateral side of the display panel 150 .
[0067] By the use of adhesive member 140 , the panel supporting part 132 of the guide frame 130 adheres to the rear edge portion of the lower substrate 152 ; or the panel supporting part 132 of the guide frame 130 adheres to the rear edge portion of the lower polarizing plate 156 . Preferably, the adhesive member 140 adheres the panel supporting part 132 of the guide frame 130 to the rear edge portion of the lower substrate 152 so as to enhance the adhesive strength between the panel supporting part 132 and the display panel 150 .
[0068] An assembling method of the display apparatus 10 according to the first embodiment of the present invention will be described as follows.
[0069] First, the bottom cover 110 or backlight unit 120 is received in the space 102 of the set cover 100 .
[0070] Then, the guide frame 130 with the panel supporting part 132 and the sealing member 134 integrated thereinto is combined with the frame supporting part 104 of the set cover 100 .
[0071] The adhesive member 140 is formed on the panel supporting part 132 of the guide frame 130 .
[0072] The display panel 150 is placed onto the panel supporting part 132 on which the adhesive member 140 is formed. On combination of the display panel 150 , after the sealing member 134 of the guide frame 130 is pushed through the lateral side of the display panel 150 , the display panel 150 is placed onto the guide frame 130 by a forcible insertion. Thus, the sealing member 134 seals the gap between the sidewall of the set cover 100 and the lateral side of the display panel 150 . Accordingly, the above sidewall of the set cover 100 and the sealing member 134 form the frontal edge portion of the display panel 150 . Also, the respective upper surfaces of the sidewall of the set cover 100 , the sealing member 134 , and the upper polarizing plate 158 are provided at the same height along the same horizontal line, thereby realizing a borderless display apparatus without a border between a screen and a frame of the display apparatus.
[0073] In the above display apparatus 10 according to the first embodiment of the present invention, the display panel 150 is supported by the use of guide frame 130 having the sealing member 134 and the panel supporting part 132 by the double injection method. Thus, it is possible to decrease a thickness of the display apparatus by removing frontal and upper cases necessarily used for the general display apparatus, and to improving the sense of beauty in the frontal view of the display apparatus by realizing the borderless display apparatus without the border between the screen and the frame of the display apparatus. Especially, in case of the display apparatus 10 according to the first embodiment of the present invention, the gap between the sidewall of the set cover 100 and the lateral side of the display panel 150 is sealed by the use of sealing member 134 of the guide frame 130 , whereby it is possible to seal (or remove) the gap between the set cover 100 and the lateral side of the display panel 150 without an additional structure, wherein the gap might occur by removing the frontal and upper cases.
[0074] The display apparatus 10 according to the first embodiment of the present invention may improve efficiency in assembling process by firstly combining the backlight unit 120 and the guide frame 130 in the set cover 100 ; and secondly combining the display panel 150 in the guide frame 130 .
[0075] FIG. 3 is a cross section view illustrating a display apparatus according to the second embodiment of the present invention.
[0076] Referring to FIG. 3 , the display apparatus 20 according to the second embodiment of the present invention includes a set cover 100 , a bottom cover 110 , a backlight unit 120 , a guide frame 130 , an adhesive member 140 , a display panel 150 , and a plurality of coupling members 160 . Except the plurality of coupling members 160 , the display apparatus 20 according to the second embodiment of the present invention is identical in structure to the display apparatus 10 according to the first embodiment of the present invention, whereby a detailed explanation for the same parts will be omitted, and the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0077] Each of the plurality of coupling members 160 enables to combine the guide frame 130 with a frame supporting part 104 of the set cover 100 by a front mounting method. Each of the plurality of coupling members 160 corresponds to a coupling screw. That is, each of the plurality of coupling members 160 is inserted into a panel supporting part 132 of the guide frame 130 and is then combined with the frame supporting part 104 of the set cover 100 , whereby the guide frame 130 is fixed into the set cover 100 by the use of coupling members 160 . A head in each of the plurality of coupling members 160 is inserted into a predetermined depth from the upper surface of the panel supporting part 132 , to thereby prevent exposure of the head in each of the plurality of coupling members 160 .
[0078] An assembling method of the display apparatus 20 according to the second embodiment of the present invention will be described as follows.
[0079] First, the bottom cover 110 or backlight unit 120 is received in the space 102 of the set cover 100 .
[0080] Then, the guide frame 130 with the panel supporting part 132 and the sealing member 134 integrated thereinto is combined with the frame supporting part 104 of the set cover 100 .
[0081] As shown in FIGS. 3 and 4 , the guide frame 130 is combined with the set cover 100 by the use of plurality coupling members 160 to be combined with the frame supporting part 104 of the set cover 100 through the panel supporting part 132 .
[0082] The adhesive member 140 is formed on the panel supporting part 132 of the guide frame 130 .
[0083] The display panel 150 is placed onto the panel supporting part 132 on which the adhesive member 140 is formed. On combination of the display panel 150 , after the sealing member 134 of the guide frame 130 is pushed through the lateral side of the display panel 150 , the display panel 150 is placed onto the guide frame 130 by a forcible insertion. Thus, the sealing member 134 seals the gap between the sidewall of the set cover 100 and the lateral side of the display panel 150 . Accordingly, the above sidewall of the set cover 100 and the sealing member 134 form the frontal edge portion of the display panel 150 . Also, the respective upper surfaces of the sidewall of the set cover 100 , the sealing member 134 , and the upper polarizing plate 158 are provided at the same height along the same horizontal line, thereby realizing a borderless display apparatus without a border between a screen and a frame of the display apparatus.
[0084] The display apparatus 20 according to the second embodiment of the present invention provides the same effects as those of the display apparatus 10 according the first embodiment of the present invention, and furthermore enhances fixation between the guide frame 130 and the set cover 100 by combining the guide frame 130 with the set cover 100 through the use of plurality coupling members 160 .
[0085] FIG. 5 is a cross section view illustrating a display apparatus according to the third embodiment of the present invention. FIG. 6 is an expanded view showing ‘A’ of FIG. 5 .
[0086] Referring to FIGS. 5 and 6 , the display apparatus 30 according to the third embodiment of the present invention includes a set cover 200 , a bottom cover 110 , a backlight unit 120 , a guide frame 230 , an adhesive member 140 , a display panel 150 , and a plurality of coupling members 160 . Except the set cover 200 and the guide frame 230 , the display apparatus 30 according to the third embodiment of the present invention is identical in structure to the display apparatus 20 according to the second embodiment of the present invention, whereby a detailed explanation for the same parts will be omitted, and the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0087] The set cover 200 includes a space 102 , a frame supporting part 104 , a frame combining part 106 , and a sidewall groove 208 . Except the sidewall groove 208 of the set cover 200 , the set cover 200 of the display apparatus 30 according to the third embodiment of the present invention is identical in structure to the set cover of the display apparatus 10 according to the first embodiment of the present invention, whereby a detailed explanation for the same parts will be omitted, and the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0088] The sidewall groove 208 is hollowly formed from the inner sidewall while being provided adjacent to the upper surface of the sidewall of the set cover 200 . That is, the sidewall groove 208 is hollowly formed to have a predetermined depth from the inner sidewall while being positioned corresponding to the upper portion of the frame supporting part 104 .
[0089] The guide frame 230 includes a panel supporting part 132 , a first sealing member 234 , and a second sealing member 236 .
[0090] The panel supporting part 132 is formed in a predetermined shape, and is placed onto the frame supporting part 104 of the set cover 100 . The panel supporting part 132 may be formed of a plastic material, and the panel supporting part 132 may be a compressed product or molded product by an extrusion molding (or extrusion injection) method. The panel supporting part 132 supports the rear edge of the display panel 150 .
[0091] The first sealing member 234 is formed as one body with the lateral side of the panel supporting part 132 , to thereby seal the gap between the display panel 150 and the set cover 200 . The first sealing member 234 is the same as the sealing member 134 of the guide frame 130 in the display apparatus 10 according to the first embodiment of the present invention, whereby a detailed explanation for the first sealing member 234 will be substituted by the above. The first sealing member 234 and the sidewall of the set cover 200 form the frontal edge portion of the display panel 150 . Also, the respective upper surfaces of the sidewall of the set cover 200 , the first sealing member 234 , and the upper polarizing plate 158 are provided at the same height along the same horizontal line, thereby realizing a borderless display apparatus without a border between a screen and a frame of the display apparatus.
[0092] The second sealing member 236 protrudes from one surface of the first sealing member 234 which confronts the sidewall of the set cover 200 , and then the protruding second sealing member 236 is inserted into the sidewall groove 208 of the set cover 200 . That is, the second sealing member 236 protruding from the first sealing member 234 has such a length as to be inserted into the sidewall groove 208 of the set cover 200 . Accordingly, the second sealing member 236 seals the sidewall groove 208 of the set cover 200 , to thereby prevent foreign matters from penetrating into the inside of the display apparatus 30 via the minute gap which might exist between the set cover 200 and the first sealing member 234 .
[0093] The panel supporting part 132 , the first sealing member 234 and the second sealing member 236 may be formed simultaneously by the double injection method or insert injection method, thereby forming the guide frame 230 .
[0094] The display apparatus 30 according to the third embodiment of the present invention may provide the same effects as those of the display apparatus 10 according to the first embodiment of the present invention or the display apparatus 20 according to the second embodiment of the present invention, and furthermore prevents the foreign matters from penetrating into the inside of the display apparatus 30 via the minute gap which might exist between the set cover 200 and the guide frame 230 .
[0095] Accordingly, the display apparatus according to the present invention comprises the guide frame having the sealing member and the panel supporting part formed by the double injection method.
[0096] In case of the display apparatus according to the present invention, it is possible to decrease the thickness by removing the upper case and the front set cover which are generally used for the related art display apparatus, thereby improving the sense of beauty in the display apparatus by realizing the borderless display apparatus without the border between the screen and the frame of the display apparatus.
[0097] Also, the gap between the sidewall of the set cover and the lateral side of the display panel is sealed by the sealing member of the guide frame so that it is possible to remove the gap between the sidewall of the set cover and the display panel, wherein the gap might occur by removing the upper case and the front set cover without additional structures.
[0098] After sequentially combining the backlight unit and the guide frame with the set cover, the display panel is combined with the guide frame, thereby improving efficiency in the combining process.
[0099] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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Discussed is a display apparatus which facilitates to minimize a thickness by innovatively removing a case and some portions of a set cover, which have been regarded as indispensible structures for the display apparatus, and simultaneously facilitates to realize a good sense of beauty in the display apparatus by a novel design, wherein the display apparatus comprises a set cover which has a space prepared by a sidewall; a display panel which includes lower and upper substrates bonded to each other; and a guide frame which supports the display panel, and seals a gap between a sidewall of the set cover and a lateral side of the display panel, wherein the guide frame is provided in the set cover.
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BACKGROUND OF THE INVENTION
The present invention relates to a burn prevention device of an iron, in particular, to a device including a shielding element, a first and a second displacement member and an actuating means such that the entire edge of the heating plate of the iron is temporarily encapsulated or shielded when the iron is placed vertically with its end base of the iron on a horizontal platform or the like.
There are different types of irons in the market and all these irons have specific features and functions in view of the structure. Some types of irons have improvements on the heating element, and some other types on the steam production, etc., but none of these irons has a burn prevention device to prevent the user from accidental contacts with the hot edge of the heating plate while ironing.
Thus, it is apparent that a new type of iron with burn prevention is desirable in order to prevent the user from contacting the hot edge of the heating plate of the iron. In accordance with the present invention, it is desirable to provide a burn prevention device which can be operated automatically to shield the heated edge of the heating plate of the iron.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to provide a burn prevention device for an iron, wherein the entire edge of the heating plate of the iron is encompassed by a shielding element.
It is another objective of the present invention to provide a burn prevention device for an iron, wherein the shielding element is made of heat resistance materials, such as plastics.
It is yet another object of the present invention to provide a burn prevention device for an iron, wherein a first and a second displacement member is respectively mounted onto the first and second lateral edge of the shielding element to automatically depress the burning prevention device to encompass the heated edge of the heating plate of the iron.
It is yet another object of the invention to provide a burn prevention device for an iron, wherein the shielding element is configured to be smoothly fitted onto the entire edge of the heating plate of the iron.
These and other objectives and advantages are achieved by the present invention which provides a burn prevention device which is operated automatically when the iron is held vertically with its end base on a horizontal platform.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully appreciated from the following detailed description when the same is considered in connection with the accompanying drawings in which:
FIG. 1 is a perspective view of the present invention showing the iron encompassed with the shielding element when the iron is placed vertically with its end base on a horizontal platform;
FIG. 2 is a perspective view of the present invention showing the shielding element being retracted to its original position when the iron is in use;
FIG. 3 is an elevational view of the iron being shielded with a burn prevention device; the dotted line indicates the position of the heavy-weighed eccentric block incorporating the first displacement member;
FIG. 4 is an exploded view of the iron in accordance with the present invention, wherein the top part of the iron has been removed to show the structure in accordance with the present invention thereof;
FIG. 5 is an elevational view of the iron in accordance with the present invention, wherein the eccentric block swings downward about the axle to depress the shielding element to encompass the edge of the heating plate of the iron;
FIG. 6 is an elevational view of the iron in accordance with the present invention, wherein the shielding element has been fully depressed by the eccentric block, and the edge of the heating plate of the iron is thus shielded; and
FIG. 7 is a sectional view along line 7--7 of FIG. 3 in accordance with the present invention, showing the retraction of the shielding element to its original position.
DETAILED DESCRIPTION OF THE INVENTION
Reference is now made to FIGS. 2, 3 and 4 which depict a burn prevention device 100 for an iron. Traditionally, the iron comprises an iron body 30, a handle 31, a base seat 32, a heating plate 33, a temperature control knob 34. In accordance with the present invention, the burning prevention device 100 comprises a shielding element 10, a first and second displacement member 12, 12' and a first 20 and a second actuating means including a heavy-weighed eccentric block 22 and a positioning plate 21. For the purpose of simplified explanation, only the structure of the first displacement member 12 and the first actuating means 20 is referred to in explanation. The iron has similar structure with that of a conventional iron. In accordance with the present invention, the burning prevention device 100 comprises the shielding element 10, the first actuating device 20, and the first displacement member 12.
The shielding element 10 has a first and a second lateral edge 11, 11' which is made from heat resistance materials, such as plastics, and is configured into the shape of the edge of the heating plate 33. For instance, the shielding element 100 is made to form a slim archshaped member, with a protruded apex 111. The shape and the size of the first and second lateral edge 11, 11' are made to shield the entire external edge of the heating plate 33. The front end of the shielding element 10 is protruded to form a protruded (apex) portion 111 to facilitate the process of ironing.
Referring to FIG. 4, an L-shaped displacement member 12, 12' are individually mounted inwardly onto the first and second lateral edge 11, 11' at the upper center region of the lateral edge 11, 11'. Each of the first and second displacement member 12, 12' has an upper edge 122 and a lower edge 123. A horizontal guiding slot 121, 121', is provided on the displacement members 12, 12' parallel to the upper edge thereof. In order to simplify manufacturing process, the shielding element 10 is formed together with the displacement member 12, 12' as one unit.
The body 30 of the iron is provided with a notch 321 at a position corresponding to the displacement member 12. The notch 321 is provided for the adaptation of the displacement member 12. The displacement member 12 is slidably vertically sitting within the notch 321.
The actuating means 20 comprise a positioning plate 21 perpendicularly mounted onto the base 32, and a heavy-weighed semi-circular eccentric block 22. By the use of an axle 23, the block 22 is rotatably mounted onto the positioning plate 21. The block 22 has a cut-off upper surface 24, and a push rod 221 is provided on the block 22 at a position to fit within the horizontal slot 121 of the displacement member 12, 121; preferably, the push rod 221 is positioned at one corner of the eccentric block 22 close to the protruded portion of the shielding element 10. The axle 23 is substantially mounted at the center of the positioning plate 21, and is adjacent to the upper surface 24 of the semi-circular eccentric block 22. Thus, due to the weight of the eccentric block 22, the eccentric block 22 remains in a downward swing position, where the upper surface 24 faces the top. A push rod 221 is mounted perpendicularly onto the eccentric block 22 such that the push rod 221 is substantially aligned with the axle 23 and is at one corner of the eccentric block 22. A stopping block 212 is mounted onto the positioning plate 21 at a position substantially corresponding to the push rod 221. This stopping block 212 restricts the rotation of the eccentric block 22 about the axle 23 when the iron is held in a vertical position. The other corner opposite to the push rod 221 is blocked by the stopping block 212, and the rotation of the block 22 about the axle 23 is thus restricted.
Referring to FIGS. 1 and 5-7, the operation of the iron in accordance with the present invention is described below. When the iron is not in use, or temporarily stopped from using, the iron is placed in a vertical position with its end base on a surface or platform. At this position, the eccentric block 22 swings about the axle 23 and stations at a position where the center of gravity of the eccentric block 22 is aligned with the axle 23. The block 22 rotates as a result of the weight of the block 22 moving about the axle 23 and the combined action of the push rod 221 and the guiding slot 121 causes the shielding element 10 to slowly move to cover the outer edge of the heating plate 33, which is shown in FIG. 5.
After the iron is placed in a vertical position, one corner (the corner opposite to the push rod 221) of the eccentric block 22 is exactly blocked by the stopping block 212. At this instance, even if the shielding element 10 is accidentally knocked or impacted by an external article, the shielding element will not retract back into its original position, which is shown in FIG. 6.
The shielding element 10 provides a protection to the user to prevent the accidental contact with the external edge of the heating plate 33. When the iron is used to iron clothes, the iron is placed horizontally with the heating plate 33 facing downward. The eccentric block 22 returns or restores to its original position which is shown by the dotted lines in FIG. 3, and the shielding element 10 moves back to a position above the edge of the heating plate 33 by means of the urging of the rotation caused by the eccentric block 22.
In the preferred embodiment in accordance with the present invention, the first and second displacement member 12, 12' is mounted individually at the first and second protective edge 11, 11' of the body of the iron respectively. A notch 321' and a second actuating means 3' are individually mounted at the body of the iron similar to that explained above as a preferred embodiment to shield the edge of the heating plate 33. Thus, the movement of the shielding element 10, under the first and second actuating means 3, 3', is smooth in operation.
Preferred embodiment has been disclosed. A person of ordinary skill in the art would realize, however, that certain modifications would come within the teaching of this invention. For instance, it may be desirable to design a different shaped eccentric block and to mount the block at a different position on the body of the iron. However, the following claims should be studied in order to determine the true scope and content of the invention.
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A burn prevention device of an iron. The device comprising a shielding element adaptable to cover the heated edge of the heating plate of an iron, and an actuating device to urge the movement of the shielding element to either cover the heated edge or restore it to its original position.
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CROSS REFERENCE TO RELATED APPLICATIONS
Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not Applicable.
BACKGROUND OF THE INVENTION
The present invention relates in general to a handset for cellular wireless telephones, and, more specifically, to a handset adapted to provide features for acting as an input manipulator for video games that can be played on the display of the handset or over the wireless network.
Guitar simulation video games such as Guitar Hero (published by RedOctane, Inc.) have become popular for game play that includes solo, cooperative, and competitive modes. Games of this type have been introduced for many different game consoles, as well as versions for personal computers and mobile cell phones. Standard game controllers have been used, such as game pads or joysticks, but many players prefer the use of mock guitar controllers specially made for the game platforms having various push buttons corresponding to guitar frets and other manipulators for controlling strumming action and tremolo or vibrato (i.e., a whammy bar). While such guitar controllers are portable in the sense that they can be taken to a friend's house of other gathering place having a game console or platform, they are too large to be conveniently carried in a pocket or purse, for example. Thus, an impromptu formation of a group of people for playing a game (i.e., a spontaneous jam session) is less likely to occur since a user desiring to play may not have a desired controller available.
Known versions of guitar simulations playable on a mobile cellular phone have not supported multi-players and have been limited to user input based on selected push buttons (i.e., keys) on the cellular phone. Furthermore, the phone display has been used as the game display so that natural and easy interaction with the game is reduced. Since no remote connectivity or network play has been supported, the normal performance expected by users of the console games has been lacking.
SUMMARY OF THE INVENTION
The present invention provides a mobile phone handset incorporating a guitar-type game manipulator that allows the player to use natural strumming and fretting techniques without reducing the utility of the phone for use as a cellular telephone. It provides a game manipulator with network connectivity for use in multi-player games employing a game server which further connects to a large display or monitor associated with a conventional game platform.
In one aspect of the invention, a cellular handset is provided for manipulating a video game. A first beam generator projects a first beam from a selected surface of the handset, and a second beam generator projects a second beam from the selected surface. A first detector proximate the selected surface detects a first manual interaction of a user with the first beam, and a second detector proximate the selected surface detects a second manual interaction of a user with the second beam. Command logic coupled to the first and second detectors interprets a first manual interaction preceding a second manual interaction as a downstroke command and interprets a second manual interaction preceding a first manual interaction as an upstroke command. The command logic is adapted to be coupled to a game controller to transmit the downstroke and upstroke commands as input to the video game.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front, plan view of a handset of the invention having a tailpiece in an extended position.
FIG. 2 is a rear, perspective view of the handset of FIG. 1 .
FIG. 3 is a side view of the handset of FIG. 1 .
FIG. 4 is a perspective view of the handset being used to control a guitar simulation game.
FIG. 5 is a signal timing diagram for interpreting manual commands via the beam detectors.
FIGS. 6-9 show an alternative embodiment of the handset for providing repositionable fret buttons for either right-handed or left-handed use.
FIG. 10 shows an alternative embodiment using two beam generators and one beam detector.
FIG. 11 is a block diagram showing the handset and video game elements in greater detail.
FIG. 12 is a block diagram showing a network system for supporting use of the handset in a multi-player gaming environment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIG. 1 , a cellular handset of the present invention includes a main body 11 having an antenna housing 12 , a graphics display 13 , and a conventional keypad 14 . Handset 10 performs all the normal functions of a cellular phone including communication of voice and/or data signals in a wireless cellular system.
Handset 10 includes additional elements providing it with the capability to act as an ergonomically realistic video game controller for video games utilizing particular combinations of manual movements such as guitar-based games to simulate the playing of a guitar (e.g., pressing fret buttons or making strumming movements according to a particular timing sequence as shown in a game display). Thus, a plurality of fret push buttons 15 - 19 is provided in a substantially straight row along one narrow side of main body 11 . To provide a natural strumming method, a pair of infrared transceivers 20 and 21 (each including a respective infrared transmitter or beam generator and a infrared detector) is disposed on a selected surface 22 of main body 11 . Preferably, surface 22 is the bottom edge of main body 11 as shown. Infrared transceiver 20 generates a first infrared beam 23 projected toward a reflector 24 . Reflector 24 is held at a spaced position from surface 22 in alignment with beam 23 in order to reflect it to the detector in transceiver 20 . Likewise, transceiver 21 generates a second infrared beam 25 projected to receiver 24 for reflection back to the detector in transceiver 21 by reflector 24 . An extension rod 26 deploys from a retention slot in main body 11 to slidably extend outward from surface 22 . Rod 26 has reflector 24 mounted at its distal end to create a strumming area 27 between surface 22 and reflector 24 . A preferred embodiment detects strumming as interruptions in beams 23 and 25 . With properly selected beam characteristics, however, it is also possible to dispense with a reflector and instead detect the reflection of a beam by the hand or other object controlled by the user. In that alternative embodiment, a return of the beam would not normally be detected except when the user makes a control action to move the hand into the beam where it can reflect some of the beam to the detector. In either embodiment, the user moves their fingers or other objects (such as a guitar pick) in strumming area 27 to create a first manual interaction with the first beam which is detected by the first detector, and a second manual interaction with the second beam which is detected by the second detector.
As described below, two infrared beams are used in order to enable detection of a strumming direction. Thus, when the first manual interaction precedes the second manual interaction, a downstroke strumming command is generated. When the second manual interaction precedes the first manual interaction, it is interpreted as an upstroke strumming command. Beams 23 and 25 may preferably be substantially parallel when leaving transceivers 20 and 21 . In order to minimize interference or crosstalk between the beams, reflector 24 preferably has a non-planar shape causing the reflected beams to slightly diverge. Thus, reflector 24 is shown having a first wing 28 and a second wing 29 wherein the ends of wings 28 and 29 are slightly further from surface 22 than at their central attachment point to extension rod 26 . In other words, reflector 24 is optically convex to diverge the reflected beams.
Infrared transceivers 20 and 21 may comprise commonly available, low cost devices such as those already used in personal digital assistance (PDA) cellular handsets for performing infrared data transmission (e.g., as an IrDA port). The transceivers typically include an infrared light emitting diode (LED) and an infrared photodetector covered by an infrared-transmitting plastic lens. Alternatively, discrete LED's and photodetectors may be employed. Furthermore, other non-infrared light sources and detectors or other proximity sensing technologies such as ultrasonics can be employed in the present invention.
As shown in FIG. 2 , main body 11 has a recess 31 for receiving extension rod 26 allowing it to retract so that reflector 24 is stowed in a recess 32 within surface 22 . Preferably, a locking mechanism (not shown) is employed within main body 11 for firmly locking extension rod 26 and reflector 24 in either a retracted or an extended position. For example, a locking system may be activated by rotating reflector 24 by 180° after it is slid to its extended position. Detents or catch mechanisms can alternatively be used to generate the locks. Since extension rod 26 is substantially straight and reflector 24 is elongated in a direction parallel with the side-to-side direction of surface 22 , recess 32 must also extend in the side-to-side direction, but it is offset (i.e., adjacent to) the location of transceivers 20 and 21 .
Because of a possible offset between the orientation of the transceivers and the positioning of the reflector by the straight rod, the reflector elements on each wing are provided with a particular shape to create a predetermined rotation of beams 23 and 25 towards the infrared transceivers. For example, the flat, reflecting surfaces of the reflector wings are sloped at an angle with respect to elongated rod 26 as shown in FIG. 3 . Thus, the predetermined rotation of the infrared beams is perpendicular to the side-to-side dimension of surface 22 . As a result, the infrared beams are more directly reflected back to the transceivers and the necessary movements of the hand through strumming area 27 is raised away from extension rod 26 so that rod 26 does not interfere with the strumming action.
In addition to a downstroke and an upstroke command, the present invention can recognize a third command in response to the hand being held in such a way that it blocks both infrared beams simultaneously. The third command can correspond with the vibrato, tremolo, or a whammy bar function (i.e., pitch bending).
FIG. 4 shows a manner of use of the handset as a guitar controller. Main body 11 is grasped in a hand 35 so that the fingers can easily reach across the front of the handset to fret buttons 15 - 19 . Reflector 24 is extended from recess 32 to create strumming area 27 within which infrared beams 23 and 25 normally circulate. A hand 36 is brought into strumming area 27 to sweep over beams 23 and 25 sequentially in a downward or upward movement. In addition, hand 36 can be placed to simultaneously interrupt beams 23 and 25 for a third command.
Detection of a strumming command is performed using the preferred method of FIG. 5 . In one preferred embodiment, the infrared generators are always on so that infrared beams 23 and 25 are continuous, thereby providing a substantially continuous received signal at both detectors. Waveforms 40 and 41 represent a logic signal that is generated in response to the detector signals and having a first logic level when a respective beam is unblocked (i.e., being received) and a second logic level when a respective beam is blocked (i.e., not being received). In the example shown, waveforms 40 and 41 have a high logic level during detection of an interruption (i.e., a manual interaction) from the two detectors.
When a first manual interaction begins wherein the users hand begins to block the first beam, waveform 40 shows a rising leading edge 42 at the corresponding time. As the user's hand moves downward in the strumming area, eventually the first beam is unblocked resulting in a trailing edge 43 in waveform 40 where the interruption detection logic signal is restored to a low logic level. The user's hand continues to move downward and eventually blocks the second beam so that waveform 41 shows a rising leading edge 44 . A delay time t d1 between leading edges 42 and 44 is determined by a logic controller which is coupled to the infrared transceivers. If delay t d1 matches a predetermined delay, then a downstroke strumming command is detected. The predetermined delay has a range of time values according to a maximum speed at which the strumming is to occur. Thus, inadvertent or incorrect blockage of the infrared beams is not interpreted as a strumming stroke. Delays within the predetermined range of times can also be detected and used to indicate different strumming speeds for use in controlling the video game, if desired. On the other hand, the minimum time delay within the range for detecting a strumming command is sufficiently long to accommodate a small error in the user's ability to block both beams simultaneously when intending to generate the third command.
An upstroke command is generated by moving the hand or fingers in an upward direction through the strumming area to generate first rising edge 45 in waveform 41 and then a second rising edge 46 in waveform 40 , wherein a time delay t d2 between rising edges 45 and 46 is within the predetermined delay range.
To provide further flexibility in generating fret commands using appropriate push buttons, the fret buttons may be mounted to a pivotally-attached swing arm having a button surface substantially perpendicular to surface 22 as shown in FIGS. 6-9 . Thus, a swing arm 50 is attached to upper and lower ends of main body 11 at pivot points 51 and 52 such that swing arm 50 swings or rotates around main body 11 over a range of at least about 180° between a right-handed playing position shown in FIG. 6 and a left-hand playing position shown in FIG. 9 . Detents or other holding mechanisms may preferably be associated with pivots 51 and/or 52 for maintaining swing arm 50 in its end positions shown in FIGS. 6 and 9 .
FIG. 7 shows swing arm 50 being rotated between opposite sides. It may be desirable to provide additional holding positions using detents at such an intermediate position to adapt use of the handset controls to a different type of video game, for example. FIG. 8 shows an end view with swing arm 50 in an intermediate position. An aperture 58 is provided through swing arm 50 to be aligned with infrared transceivers 20 and 21 when in its end positions so that swing arm 50 does not interfere with the infrared beams.
FIG. 10 shows an alternative embodiment employing a pair of beam generators comprising infrared LED's 60 and 61 generating beams 62 and 63 which are projected toward a reflector 64 . Due to a slightly concave shape of reflector 64 , beams 62 and 63 are converged to a single detector 65 . Instead of providing reflector 64 with a non-planar shape to converge the beams, an optically modified surface such as a series of saw tooth-shaped grooves can alternatively be used.
In order to separately detect interruption of beams 62 and 63 using a single detector 65 , the beams are modulated in different ways in order to enable reception of each beam to be distinguishable. One modulation scheme is to alternately pulse each LED 60 and 61 to alternately produce a detectable signal at detector 65 . Pulsing is required to occur at a period shorter than the time in which significant movement of the hand sweeping through the strumming area could move an appreciable distance compared to the width of the beams.
Alternatively, each beam can be modulated with an information content that is uniquely recoverable by detector 65 to detect at what times each beam is still being received. For example, each beam can be amplitude modulated or frequency modulated according to unique frequencies or information content that are non-overlapping. Various code transmission protocols could be used as are known in the art.
A hardware implementation of the present information is shown in greater detail in FIG. 11 . A first LED 70 and a first photodetector 71 are coupled to an interface and driver circuit 72 . Devices 70 - 72 may comprise a commercially available infrared transceiver, for example. Interface and driver circuit 72 operates under control of command logic 73 . In one preferred embodiment, command logic 73 provides an activation signal to driver and interface circuit 72 when the handset is in a mode to detect strumming commands. Interface and driver circuit 72 automatically controls operation of LED 70 and photodetector 71 and provides an interruption signal to command logic 73 when its respective beam is being interrupted. When a single detector is being used, modulation of the beam and demodulation of the detected beam may preferably be performed by interface and driver circuit 72 , but could alternative be handled by command logic block 73 . A second LED 74 and photodetector 75 are connected to another interface and driver circuit 76 similarly connected to command logic 73 . Fret buttons 77 are coupled to command logic 73 through an interface 78 .
Command logic 73 compares interruption events detected for each respective beam to interpret the occurrence of upstroke and downstroke commands, as well as the third command representing the pitch bending function. Thus, if interruption events occur with rising edges within a predetermined shortest delay time, then a third command is generated. If interruption events occur according to a delay within the predetermined delay range, then an upstroke or downstroke command is generated. The generated commands are provided to a game controller 80 which is coupled to a game display 81 . Game controller 80 implements the actual video game software such as the guitar simulation and may reside either on the handset itself or remotely on a game platform accessed by the handset over the cellular network.
FIG. 12 shows a network system for supporting multiplayer games accessible to a player using a handset 82 of the present invention. Handset 82 wirelessly connects to a base station 83 in turn coupled to a base station controller (BSC) 84 . The wireless cellular system preferably supports digital data transmission to a packet data serving node (PDSN) 85 which is coupled to an IP network 90 (which may preferably be owned and operated by the wireless service provider). A central game controller 91 is coupled to IP network 90 and implements the video game in response to inputs from the player using handset 82 . A second player using a handset 86 may be similarly coupled to a base station 87 and a BSC 88 in order to send digital data commands to PDSN 85 for forwarding to game controller 91 through IP network 90 . Game controller 91 may be configured to provide video game output to a designated set top box (STB) 92 associated with a television display 93 . Thus, the players using handsets 82 and 86 do not need to view the game using displays on their handsets but can playing the video game from the location of TV monitor 93 to view the game display. Additional players can be joined to a game from a PC or other game console 94 coupled by a gateway 95 to IP network 90 . Alternatively, a PC or console 94 can be utilized by game controller 91 as the game display.
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A cellular handset and video game manipulator has first and second beam generators projecting first and second beams from a selected surface of the handset. First and second detectors proximate the selected surface detect first and second manual interactions of a user with the beams. Command logic coupled to the first and second detectors interprets a first manual interaction preceding a second manual interaction as a downstroke command and interprets a second manual interaction preceding a first manual interaction as an upstroke command. The command logic is adapted to be coupled to a game controller to transmit the downstroke and upstroke commands as input to a video game, such as a guitar simulation. The player enjoys natural strumming and fretting techniques without reducing the utility of the phone for use as a cellular telephone. Network connectivity is provided to enable use in multi-player games employing a game server which further connects to a large display or monitor associated with a conventional game platform.
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CROSS-REFERENCE TO OTHER APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 10/383,805 filed by Shilin Chen on Mar. 8, 2003, which is a continuation of U.S. patent application Ser. No. 09/833,016 filed by Shilin Chen on Apr. 10, 2001, which is a continuation of U.S. patent application Ser. No. 09/387,737 filed by Shilin Chen on Aug. 31, 1999, now U.S. Pat. No. 6,213,225, which claims the benefit of U.S. Provisional Application Ser. No. 60/098,466 filed on Aug. 31, 1998, which is hereby incorporated by reference.
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to down-hole drilling, and especially to the optimization of drill bit parameters.
BACKGROUND: ROTARY DRILLING
Oil wells and gas wells are drilled by a process of rotary drilling, using a drill rig such as is shown in FIG. 10 . In conventional vertical drilling, a drill bit 10 is mounted on the end of a drill string 12 (drill pipe plus drill collars), which may be miles long, while at the surface a rotary drive (not shown) turns the drill string, including the bit at the bottom of the hole.
Two main types of drill bits are in use, one being the roller cone bit, an example of which is seen in FIG. 11 . In this bit a set of cones 16 (two are visible) having teeth or cutting inserts 18 are arranged on rugged bearings on the arms of the bit. As the drill string is rotated, the cones will roll on the bottom of the hole, and the teeth or cutting inserts will crush the formation beneath them. (The broken fragments of rock are swept uphole by the flow of drilling fluid.) The second type of drill bit is a drag bit, having no moving parts, seen in FIG. 12 .
There are various types of roller cone bits: insert-type bits, which are normally used for drilling harder formations, will have teeth of tungsten carbide or some other hard material mounted on their cones. As the drill string rotates, and the cones roll along the bottom of the hole, the individual hard teeth will induce compressive failure in the formation. The bit's teeth must crush or cut rock, with the necessary forces supplied by the “weight on bit” (WOB) which presses the bit down into the rock, and by the torque applied at the rotary drive.
BACKGROUND: DRILL STRING OSCILLATION
The individual elements of a drill string appear heavy and rigid. However, in the complete drill string (which can be more than a mile long), the individual elements are quite flexible enough to allow oscillation at frequencies near the rotary speed. In fact, many different modes of oscillation are possible. (A simple demonstration of modes of oscillation can be done by twirling a piece of rope or chain: the rope can be twirled in a flat slow circle, or, at faster speeds, so that it appears to cross itself one or more times.) The drill string is actually a much more complex system than a hanging rope, and can oscillate in many different ways; see WAVE PROPAGATION IN PETROLEUM ENGINEERING, Wilson C. Chin, (1994).
The oscillations are damped somewhat by the drilling mud, or by friction where the drill pipe rubs against the walls, or by the energy absorbed in fracturing the formation: but often these sources of damping are not enough to prevent oscillation. Since these oscillations occur down in the wellbore, they can be hard to detect, but they are generally undesirable. Drill string oscillations change the instantaneous force on the bit, and that means that the bit will not operate as designed. For example, the bit may drill oversize, or off-center, or may wear out much sooner than expected. Oscillations are hard to predict, since different mechanical forces can combine to produce “coupled modes”; the problems of gyration and whirl are an example of this.
BACKGROUND: OPTIMAL DRILLING WITH VARIOUS FORMATION TYPES
There are many factors that determine the drillability of a formation. These include, for example, compressive strength, hardness and/or abrasiveness, elasticity, mineral content (stickiness), permeability, porosity, fluid content and interstitial pressure, and state of underground stress.
Soft formations were originally drilled with “fish-tail” drag bits, which sheared the formation. Fish-tail bits are obsolete, but shear failure is still very useful in drilling soft formations. Roller cone bits designed for drilling soft formations are designed to maximize the gouging and scraping action, in order to exploit both shear and compressive failure. To accomplish this, cones are offset to induce the largest allowable deviation from rolling on their true centers. Journal angles are small and cone-profile angles will have relatively large variations. Teeth are long, sharp, and widely-spaced to allow for the greatest possible penetration. Drilling in soft formations is characterized by low weight and high rotary speeds.
Hard formations are drilled by applying high weights on the drill bits and crushing the formation in compressive failure. The rock will fail when the applied load exceeds the strength of the rock. Roller cone bits designed for drilling hard formations are designed to roll as close as possible to a true roll, with little gouging or scrapping action. Offset will be zero and journal angles will be higher. Teeth are short and closely spaced to prevent breakage under the high loads. Drilling in hard formations is characterized by high weight and low rotary speeds.
Medium formations are drilled by combining the features of soft and hard formation bits. The rock is failed by combining compressive forces with limited shearing and gouging action that is achieved by designing drill bits with a moderate amount of offset. Tooth length is designed for medium extensions as well. Drilling in medium formations is most often done with weights and rotary speeds between that of the hard and soft formations.
BACKGROUND: ROLLER CONE BIT DESIGN
The “cones” in a roller cone bit need not be perfectly conical (nor perfectly frustroconical), but often have a slightly swollen axial profile. Moreover, the axes of the cones do not have to intersect the centerline of the borehole. (The angular difference is referred to as the “offset” angle.) Another variable is the angle by which the centerline of the bearings intersects the horizontal plane of the bottom of the hole, and this angle is known as the journal angle. Thus as the drill bit is rotated, the cones typically do not roll true, and a certain amount of gouging and scraping takes place. The gouging and scraping action is complex in nature, and varies in magnitude and direction depending on a number of variables.
Conventional roller cone bits can be divided into two broad categories: Insert bits and steel-tooth bits. Steel tooth bits are utilized most frequently in softer formation drilling, whereas insert bits are utilized most frequently in medium and hard formation drilling.
Steel-tooth bits have steel teeth formed integral to the cone. (A hard facing is typically applied to the surface of the teeth to improve the wear resistance of the structure.) Insert bits have very hard inserts (e.g. specially selected grades of tungsten carbide) pressed into holes drilled into the cone surfaces. The inserts extend outwardly beyond the surface of the cones to form the “teeth” that comprise the cutting structures of the drill bit.
The design of the component elements in a rock bit are interrelated (together with the size limitations imposed by the overall diameter of the bit), and some of the design parameters are driven by the intended use of the product. For example, cone angle and offset can be modified to increase or decrease the amount of bottom hole scraping. Many other design parameters are limited in that an increase in one parameter may necessarily result in a decrease of another. For example, increases in tooth length may cause interference with the adjacent cones.
BACKGROUND: TOOTH DESIGN
The teeth of steel tooth bits are predominantly of the inverted “V” shape. The included angle (i.e. the sharpness of the tip) and the length of the tooth will vary with the design of the bit. In bits designed for harder formations the teeth will be shorter and the included angle will be greater. Gage row teeth (i.e. the teeth in the outermost row of the cone, next to the outer diameter of the borehole) may have a “T” shaped crest for additional wear resistance.
The most common shapes of inserts are spherical, conical, and chisel. Spherical inserts have a very small protrusion and are used for drilling the hardest formations. Conical inserts have a greater protrusion and a natural resistance to breakage, and are often used for drilling medium hard formations.
Chisel shaped inserts have opposing flats and a broad elongated crest, resembling the teeth of a steel tooth bit. Chisel shaped inserts are used for drilling soft to medium formations. The elongated crest of the chisel insert is normally oriented in alignment with the axis of cone rotation. Thus, unlike spherical and conical inserts, the chisel insert may be directionally oriented about its center axis. (This is true of any tooth which is not axially symmetric.) The axial angle of orientation is measured from the plane intersecting the center of the cone and the center of the tooth.
BACKGROUND: BOTTOM HOLE ANALYSIS
The economics of drilling a well are strongly reliant on rate of penetration. Since the design of the cutting structure of a drill bit controls the bit's ability to achieve a high rate of penetration, cutting structure design plays a significant role in the overall economics of drilling a well.
It has long been desirable to predict the development of bottom hole patterns on the basis of the controllable geometric parameters used in drill bit design, and complex mathematical models can simulate bottom hole patterns to a limited extent. To accomplish this it is necessary to understand first, the relationship between the tooth and the rock, and second, the relationship between the design of the drill bit and the movement of the tooth in relation to the rock. It is also known that these mechanisms are interdependent.
To better understand these relationships, much work has been done to determine the amount of rock removed by a single tooth of a drill bit. As can be seen by the forgoing discussion, this is a complex problem. For many years it has been known that rock failure is complex, and results from the many stresses arising from the combined movements and actions of the tooth of a rock bit. (Sikarskie, et al, P ENETRATION P ROBLEMS IN R OCK M ECHANICS , ASME Rock Mechanics Symposium, 1973). Subsequently, work was been done to develop quantitative relationships between bit design and tooth-formation interaction. This has been accomplished by calculating the vertical, radial and tangential movement of the teeth relative to the hole bottom, to accurately represent the gouging and scrapping action of the teeth on roller cone bits. (Ma, A N EW W AY TO C HARACTERIZE THE G OUGING -S CRAPPING A CTION OF R OLLER C ONE B ITS , Society of Petroleum Engineers No. 19448, 1989). More recently, computer programs have been developed which predict and simulate the bottom hole patterns developed by roller cone bits by combining the complex movement of the teeth with a model of formation failure. (Ma, T HE C OMPUTER S IMULATION OF THE I NTERACTION B ETWEEN T HE R OLLER B IT AND R OCK , Society of Petroleum Engineers No. 29922, 1995). Such formation failure models include a ductile model for removing the formation occupied by the tooth during its movement across the bottom of the hole, and a fragile breakage model to represent the surrounding breakage.
Currently, roller cone bit designs remain the result of generations of modifications made to original designs. The modifications are based on years of experience in evaluating bit run records and dull bit conditions. Since drill bits are run under harsh conditions, far from view, and to destruction, it is often very difficult to determine the cause of the failure of a bit. Roller cone bits are often disassembled in manufacturers' laboratories, but most often this process is in response to a customer's complaint regarding the product, when a verification of the materials is required. Engineers will visit the lab and attempt to perform a forensic analysis of the remains of a rock bit, but with few exceptions there is generally little evidence to support their conclusions as to which component failed first and why. Since rock bits are run on different drilling rigs, in different formations, under different operating conditions, it is extremely difficult draw conclusion from the dull conditions of the bits. As a result, evaluating dull bit conditions, their cause, and determining design solutions is a very subjective process. What is known is that when the cutting structure or bearing system of a drill bit fails prematurely, it can have a serious detrimental effect of the economics of drilling.
Though numerical methods are now available to model the bottom hole pattern produced by a roller cone bit, there is no suggestion as to how this should be used to improve the design of the bits other than to predict the presence of obvious problems such as tracking. For example, the best solution available for dealing with the problems of lateral vibration, is a recommendation that roller cone bits should be run at low to moderate rotary speeds when drilling medium to hard formations to control bit vibrations and prolong life, and to use downhole vibration sensors. (Dykstra, et al, EXPERIMENTAL EVALUATIONS OF DRILL STRING DYNAMICS, Amoco Report Number F94-P-80, 1994).
Force-Balanced Roller-Cone Bits, Systems, Drilling Methods, and Design Methods
The present application describes improved methods for designing roller cone bits, as well as improved drilling methods, and drilling systems. The present application teaches that roller cone bit designs should have equal mechanical downforce on each of the cones. This is not trivial: without special design consideration, the weight on bit will NOT automatically be equalized among the cones.
Roller-cone bits are normally NOT balanced, for several reasons:
Asymmetric cutting structures. Usually the rows on cones are intermeshed in order to cover fully the hole bottom and have a self-clearance effects. Therefore, even the cone shapes may be the same for all three cones, the teeth row distributions on cones are different from cone to cone. The number of teeth on cones are usually different. Therefore, the cone having more row and more teeth than other two cones may remove more rock and as a results, may spent more energy (Energy Imbalance). An energy imbalance usually leads to bit force imbalance.
Offset effects. Because of the offset, a scraping motion will be induced. This scraping motion is different from teeth row to teeth row and as a result, the scraping force (tangent force) acting on teeth is different from row to row. This will generate an imbalance force on bit.
Tracking effects. If at least one of the cones is in tracking, then this cone will gear with the hole bottom without penetration, the rock not removed by this cone will be partly removed by other two cones. As a result, the bit is unbalanced.
The applicant has discovered, and has experimentally verified, that equalization of downforce per cone is a very important (and greatly underestimated) factor in roller cone performance. Equalized downforce is believed to be a significant factor in reducing gyration, and has been demonstrated to provide substantial improvement in drilling efficiency. The present application describes bit design procedures which provide optimization of downforce balancing as well as other parameters.
A roller-cone bit will always be a strong source of vibration, due to the sequential impacts of the bit teeth and the inhomogeneities of the formation. However, many results of this vibration are undesirable. It is believed that the improved performance of balanced-downforce cones is partly due to reduced vibration.
Any force imbalance at the cones corresponds to a bending torque, applied to the bottom of the drill string, which rotates with the drill string. This rotating bending moment is a driving force, at the rotary frequency, which has the potential to couple to oscillations of the drill string. Moreover, this rotating bending moment may be a factor in biasing the drill string into a regime where vibration and instabilities are less heavily damped. It is believed that the improved performance of balanced-downforce cones may also be partly due to reduced oscillation of the drill string.
The disclosed innovations, in various embodiments, provide one or more of at least the following advantages:
The roller cone bit is force balanced such that axial loading between the arms is substantially equal. The roller cone bit is energy balanced such that each of the cutting structures drill substantially equal volumes of formation. The drill bit has decreased axial and lateral operating vibration. The cutting structures, bearings, and seals have increased lifetime and improved performance and durability. Drill string life is extended. The roller cone bit has minimized tracking of cutting structures, giving improved performance and extending cutting structure life. The roller cone bit has an optimized number of teeth in a given formation area. Bit performance is improved. Off-center rotation is minimized. The roller cone bit has optimized (minimized and equalized) uncut formation ring width. Energy balanced roller cone bits can be further optimized by minimizing cone and bit tracking. Energy balanced roller cone bits can be further optimized by minimizing and equalizing uncut formation rings. Designer can evaluate the force balance and energy balance conditions of existing bit designs. Designer can design force balanced drill bits with predictable bottom hole patterns without relying on lab tests followed by design modifications. Designer can optimize the design of roller cone drill bits within designer-chosen constraints.
Other advantages of the various disclosed inventions will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, a sample embodiment is disclosed.
U.S. patent application Ser. No. 09/387,304, filed 31 Aug. 1999, entitled “Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimization of Tooth Orientation”, now U.S. Pat. No. 6,095,262 and claiming priority from U.S. Provisional Application No. 60/098,442 filed 31 Aug. 1998, describes roller cone drill bit design methods and optimizations which can be used separately from or in synergistic combination with the methods disclosed in the present application. That application, which has common ownership, inventorship, and effective filing date with the present application, and its provisional priority application, are both hereby incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosed inventions will be described with reference to the accompanying drawings, which show important sample embodiments of the invention and which are incorporated in the specification hereof by reference, wherein:
FIG. 1 shows an element and how the tooth is divided into elements for tooth force evaluation.
FIG. 2 diagrammatically shows a roller cone and the bearing forces which are measured in the current disclosure.
FIG. 3 shows the four design variables of a tooth on a cone.
FIG. 4 shows the bottom hole pattern generated by a steel tooth bit.
FIG. 5 shows the layout of row distribution in a plane showing the distance between any two tooth surfaces.
FIG. 6 shows a flowchart of the optimization procedure to design a force balanced bit.
FIGS. 7A–C compare the three cone profiles before and after optimization.
FIGS. 8A–B compare the bottom hole pattern before and after optimization.
FIGS. 9A–B compare the cone layout before and after optimization.
FIG. 10 shows an example of a drill rig which can use bits designed by the disclosed method.
FIG. 11 shows an example of a roller cone bit.
FIG. 12 shows an example of a drag bit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The numerous innovative teachings of the present application will be described with particular reference to the presently preferred embodiment (by way of example, and not of limitation).
Rock Bit Computer Model
The present invention uses a single element force-cutting relationship in order to develop the total force-cutting relationship of a cone and of an entire roller cone bit. Looking at FIG. 1 , each tooth, shown on the right side, can be thought of as composed of a collection of elements, such as are shown on the left side. Each element used in the present invention has a square cross section with area S e (its cross-section on the x-y plane) and length L e (along the z axis). The force-cutting relationship for this single element may be described by:
F ze =k e *σ*S e (1)
F xe =μ x *F ze (2)
F ye =μ y *F ze (3)
where F ze is the normal force and F x e, F ye are side forces, respectively, σ is the compressive strength, S e the cutting depth and k e , μ x and μ y are coefficient associated with formation properties. These coefficients may be determined by lab test. A tooth or an insert can always be divided into several elements. Therefore, the total force on a tooth can be obtained by integrating equation (1) to (3). The single element force model used in the invention has significant advantage over the single tooth or single insert model used in most of the publications. The only way to obtain a force model is by lab test. There are many types of inserts used today for roller cone bit depending on the rock type drilled. If the single insert force model is used, a lot of tests have to be done and this is very difficult if not impossible. By using the element force model, only a few tests may be enough because any kind of insert or tooth can be always divided into elements. In other words, one element model may be applied to all kinds of inserts or teeth.
After having the single element force model, the next step is to determine the interaction between inserts and the formation drilled. This step involves the determination of the tooth kinematics (local) from the bit and cone kinematics (global) as described below.
(1) The bit kinematics is described by bit rotation speed, Ω=RPM (revolutions per minute), and the rate of penetration, ROP. Both RPM and ROP may be considered as constant or as function with time.
(2) The cone kinematics is described by cone rotational speed. Each cone may have its own speed. The initial value is calculated from the bit geometric parameters or just estimated from experiment. In the calculation the cone speed may be changed based on the torque acting on the cone.
(3) At the initial time, t 0 , the hole bottom is considered as a plane and is meshed into small grids. The tooth is also meshed into grids (single elements). At any time t, the position of a tooth in space is fully determined. If the tooth is in interaction with the hole bottom, the hole bottom is updated and the cutting depth for each cutting element is calculated and the forces acting on the elements are obtained.
(4) The element forces are integrated into tooth forces, the tooth forces are integrated into cone forces, the cone forces are transferred into bearing forces and the bearing forces are integrated into bit forces.
(5) After the bit is fully drilled into the rock, these forces are recorded at each time step. A period time usually at least 10 seconds is simulated. The average forces may be considered as static forces and are used for evaluation of the balance condition of the cutting structure.
Evaluation of A Force Balanced Roller Cone Bit
The applied forces to bit are the weight on bit (WOB) and torque on bit (TOB). These forces will be taken by three cones. Due to the asymmetry of bit geometry, the loads on three cones are usually not equal. In other words, one of the three cones may do much more work than other two cones. With reference to FIG. 2 , the balance condition of a roller cone bit may be evaluated using the following criteria:
Max(ω 1 , ω 2 , ω 3 )−Min(ω 1 , ω 2 , ω 3 )<=ω 0 (4)
Max(η 1 , η 2 , η 3 )−Min(η 1 , η 2 , η 3 )<=η 0 (5)
Max(λ 1 , λ 2 , λ 3 )−Max(λ 1 , λ 2 , λ 3 )<=λ 0 (6)
ξ= F r /WOB 100%<=ξ 0 (7)
where ωi (i=1, 2, 3) is defined by ωi=WOBi/WOB*100%, WOBi is the weight on bit taken by cone i. ηi is defined by ηi=Fzi/ΣFzi*100% with Fzi being the i-th cone axial force. And λi is defined by λi=Mzi/ΣMzi*100% with Mzi being the i-th cone moment in the direction perpendicular to i-th cone axis. Finally ξ is the bit imbalance force ratio with F r being the bit imbalance force. A bit is perfectly balanced if:
ω 1 =ω 2 =ω 3 =33.333% or ω 0 =0.0%
η 1 =η 2 =η 3 =33.333% or η 0 =0.0%
λ 1 =λ 2 =λ 3 =33.333% or λ 0 =0.0%
ξ=0.0%
In most cases if ω 0 , η 0 , λ 0 , ξ 0 are controlled with some limitations, the bit is balanced. The values of ω 0 , η 0 , λ 0 , ξ 0 depend on bit size and bit type.
There is a distinction between force balancing techniques and energy balancing. A force balanced bit uses multiple objective optimization technology, which considers weight on bit, axial force, and cone moment as separate optimization objectives. Energy balancing uses only single objective optimization, as defined in equation (11) below.
Design of A Force Balanced Roller Cone Bit
As we stated in previous sections, there are many parameters which affect bit balance conditions. Among these parameters, the teeth crest length, their positions on cones (row distribution on cone) and the number of teeth play a significant role. An increase in the size of any one parameter must of necessity result in the decrease or increase of one or more of the others. And in some cases design rules may be violated. Obviously the development of optimization procedure is absolutely necessary.
The first step in the optimization procedure is to choose the design variables. Consider a cone of a steel tooth bit as shown in FIG. 3 . The cone has three rows. For the sake of simplicity, the journal angle, the offset and the cone profile will be fixed and will not be as design variables. Therefore the only design variables for a row are the crest length, Lc, the radial position of the center of the crest length, Rc, and the tooth angles, α and β. Therefore, the number of design variables is 4 times of the total number of rows on a bit.
The second step in the optimization procedure is to define the objectives and express mathematically the objectives as function of design variables. According to equation (1), the force acting on an element is proportional to the rock volume removed by that element. This principle also applies to any tooth. Therefore, the objective is to let each cone remove the same amount of rock in one bit revolution. This is called volume balance or energy balance. The present inventor has found that an energy balanced bit will lead to force balanced in most cases. Consider FIG. 4 which shows the patterns cut by each cone on the hole bottom. The first rows of all three cones have overlap and the inner rows remove the rock independently. Suppose the bit has a cutting depth Δ in one bit revolution. It is not difficult to calculate the volumes removed by each row and the volume matrix may have the form:
V=[V ij ], i=1,2,3; j=1,2,3,4, (8)
where i represent the cone number and j the row number. For example, V 32 is the element in the volume matrix representing the rock volume removed by the second row of the third cone. The elements V ij of this matrix are all functions of the design variables.
In reality, the removed volume by each row depends not only on the above design variables, but also on the number of teeth on that row and the tracking condition. Therefore the volume matrix calculated in a 2D manner must be scaled. The scale matrix, K v , may be obtained as follows.
K v ( i,j )= V 3d0 ( ij )/ V 2d0 ( i,j ) (9)
where V 3d0 is the volume matrix of the initial designed bit (before optimization). V 3d0 is obtained from the rock bit computer program by simulate the bit drilling procedure at least 10 seconds. V 2d0 is the volume matrix associated with the initial designed matrix and obtained using the 2D manner based on the bottom pattern shown in FIG. 4 . The volume matrix has the final form:
V b ( ij )= K v ( ij )* V ( ij )= f v ( L c , R c , α, β) (10)
Let V 1 , V 2 and V 3 be the volume removed by cone 1,2 and 3, respectively. For the energy balance, the objective function takes the following form:
Obj =( V 1 −V m )^2+( V 2 −V m ) ^2+( V 3 −V m ) ^2 (11)
where V m =(V 1 +V 2 +V 3 )/3;
The third step in the optimization procedure is to define the bounds of the design variables and the constraints. The lower and upper bounds of design variables can be determined by requirements on element strength and structural limitation. For example, the lower bound of a tooth crest length is determined by the tooth strength. The angle α and β may be limited to 0˜45 degrees. One of the most important constraints is the interference between teeth on different cones. A minimum clearance between teeth surface must be kept. Consider FIG. 5 where cone profile is shown in a plane. A minimum clearance between tooth surfaces is required. This clearance can be expressed as a function of the design variables.
Δ d=f d ( L c , R c , α, β) (12)
Another constraint is the width of the uncut formation rings on bottom. The width of the uncut formation rings should be minimized or equalized in order to avoid the direct contact of cone surface to formation drilled. These constraints can be expressed as:
Δ w min <=Δwi=fw i ( L c , R c , α, β)<=Δ w max (13)
There may be other constraints, for example, the minimum space between two neighbored rows on the same cone required by the mining process.
After having the objective function, the bounds and the constraints, the problem is simplified to a general nonlinear optimization problem with bounds and nonlinear constraints which can be solved by different methods. FIG. 6 shows the flowchart of the optimization procedure. The procedure begins by reading the bit geometry and other operational parameters. The forces on the teeth, cones, bearings, and bit are then calculated. Once the forces are known, they are compared, and if they are balanced, then the design is optimized. If the forces are not balanced, then the optimization must occur. Objectives, constraints, design variables and their bounds (maximum and minimum allowed values) are defined, and the variables are altered to conform to the new objectives. Once the new objectives are met, the new geometric parameters are used to re-design the bit, and the forces are again calculated and checked for balance. This process is repeated until the desired force balance is achieved.
As an example, FIGS. 7A–C show the row distributions on three cones of a 9″ steel tooth bit before and after optimization. FIGS. 8A and 8B compare the bottom hole patterns cut by the different cones before and after optimization. FIGS. 9A and B compare the cone layouts before and after optimization.
In the preferred embodiment of the present disclosure, a roller cone bit is provided for which the volume of formation removed by each tooth in each row, of each cutting structure (cone), is calculated. This calculation is based on input data of bit geometry, rock properties, and operational parameters. The geometric parameters of the roller cone bit are then modified such that the volume of formation removed by each cutting structure is equalized. Since the amount of formation removed by any tooth on a cutting structure is a function of the force imparted on the formation by the tooth, the volume of formation removed by a cutting structure is a direct function of the force applied to the cutting structure. By balancing the volume of formation removed by all cutting structures, force balancing is also achieved.
As another feature of the preferred embodiment, a roller cone bit is provided for which the width of the rings of formation remaining uncut is calculated, as it remains between the rows of the intermeshing teeth of the different cutting structures. The geometric parameters of the roller cone bit are then modified such that the width of the uncut area for each row is substantially minimized and equalized within selected acceptable limits. By minimizing the uncut rings on the bottom of the hole, the bit will be able to crush the uncut rings upon successive rotations due to the craters of formation removed immediately adjacent to the uncut rings. By equalizing the width of the uncut rings, the force required to crush the rings will be even from any point on the hole face, such that as cutting elements (teeth) engage the rings on successive rotations, the rings act to uniformly retain the bit drilling on-enter.
According to a disclosed class of innovative embodiments, there is provided: A roller cone drill bit comprising: a plurality of arms; rotatable cutting structures mounted on respective ones of said arms; and a plurality of teeth located on each of said cutting structures; wherein approximately the same axial force is acting on each of said cutting structure.
According to another disclosed class of innovative embodiments, there is provided: A roller cone drill bit comprising: a plurality of arms; rotatable cutting structures mounted on respective ones of said arms; and a plurality of teeth located on each of said cutting structures; wherein a substantially equal volume of formation is drilled by each said cutting structure.
According to another disclosed class of innovative embodiments, there is provided: A rotary drilling system, comprising: a drill string which is connected to conduct drilling fluid from a surface location to a rotary drill bit; a rotary drive which rotates at least part of said drill string together with said bit said rotary drill bit comprising a plurality of arms; rotatable cutting structures mounted on respective ones of said arms; and a plurality of teeth located on each of said cutting structures; wherein approximately the same axial force is acting on each said cutting structure.
According to another disclosed class of innovative embodiments, there is provided: A method of designing a roller cone drill bit, comprising the steps of: (a) calculating the volume of formation cut by each tooth on each cutting structure; (b) calculating the volume of formation cut by each cutting structure per revolution of the drill bit; (c) comparing the volume of formation cut by each of said cutting structures with the volume of formation cut by all others of said cutting structures of the bit; (d) adjusting at least one geometric parameter on the design of at least one cutting structure; and (e) repeating steps (a) through (d) until substantially the same volume of formation is cut by each of said cutting structures of said bit.
According to another disclosed class of innovative embodiments, there is provided: A method of designing a roller cone drill bit, the steps of comprising: (a) calculating the axial force acting on each tooth on each cutting structure; (b) calculating the axial force acting on each cutting structure per revolution of the drill bit; (c) comparing the axial force acting on each of said cutting structures with the axial force on the other ones of said cutting structures of the bit; (d) adjusting at least one geometric parameter on the design of at least one cutting structure; (e) repeating steps (a) through (d) until approximately the same axial force is acting on each cutting structure.
According to another disclosed class of innovative embodiments, there is provided: A method of designing a roller cone drill bit, the steps of comprising: (a) calculating the force balance conditions of a bit; (b) defining design variables; (c) determine lower and upper bounds for the design variables; (d) defining objective functions; (e) defining constraint functions; (f) performing an optimization means; and, (g) evaluating an optimized cutting structure by modeling.
According to another disclosed class of innovative embodiments, there is provided: A method of using a roller cone drill bit, comprising the step of rotating said roller cone drill bit such that substantially the same volume of formation is cut by each roller cone of said bit.
According to another disclosed class of innovative embodiments, there is provided: A method of using a roller cone drill bit, comprising the step of rotating said roller cone drill bit such that substantially the same axial force is acting on each roller cone of said bit.
Modifications and Variations
As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a tremendous range of applications, and accordingly the scope of patented subject matter is not limited by any of the specific exemplary teachings given.
Additional general background, which helps to show the knowledge of those skilled in the art regarding implementations and the predictability of variations, may be found in the following publications, all of which are hereby incorporated by reference: A PPLIED D RILLING E NGINEERING , Adam T. Bourgoyne Jr. et al., Society of Petroleum Engineers Textbook series (1991), O IL AND G AS F IELD D EVELOPMENT T ECHNIQUES : D RILLING , J.-P. Nguyen (translation 1996, from French original 1993), M AKING H OLE (1983) and D RILLING M UD (1984), both part of the Rotary Drilling Series, edited by Charles Kirkley.
None of the description in the present application should be read as implying that any particular element, step, or function is an essential element which must be included in the claim scope: THE SCOPE OF PATENTED SUBJECT MATTER IS DEFINED ONLY BY THE ALLOWED CLAIMS. Moreover, none of these claims are intended to invoke paragraph six of 35 USC section 112 unless the exact words “means for” are followed by a participle.
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Roller cone drilling wherein the bit optimization process equalizes the downforce (axial force) for the cones (as nearly as possible, subject to other design constraints).
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CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 09/041,518, filed Mar. 12, 1998, U.S. Pat. No. 6,066,509, which is a continuation of application Ser. No. 08/612,125, filed Mar. 7, 1996, now U.S. Pat. No. 5,766,982, issued Jun. 16, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for underfilling a semiconductor device. More specifically, the present invention relates to a method and apparatus for uniformly underfilling a bumped or raised semiconductor chip to be essentially void free.
2. State of the Prior Art
Flip-chip and bumped die technology is well known in the art. A flip-chip or bumped (raised) die is a semiconductor chip (die) having bumps on the bond pads formed on the active circuit or front side thereof, the bumps being used as electrical and mechanical connectors, which is inverted (flipped) and bonded to a substrate by means of the bumps. Several materials are typically used to form the bumps on the die, such as conductive polymers, solder, etc. Typically, if the bumps are solder bumps, the solder bumps are reflowed to form a solder joint between the so-called flip-chip and the substrate, the solder joint forming both electrical and mechanical connections between the flip-chip and substrate. In any event, due to the presence of the bumps on the flip-chip, a gap exists between the substrate and the bottom surface of the flip-chip.
Typically, since the flip-chip and the substrate have different coefficients of thermal expansion and operate at different temperatures and also have different mechanical properties with differing attendant reactions to mechanical loading and stresses, stress develops in the joints formed by the bumps between the flip-chip nd substrate. Therefore, the bumps must be sufficiently robust to withstand such stressful conditions to maintain the joint between the flip-chip and the substrate. To enhance the joint integrity formed by the bumps located between the flip-chip and the substrate, an underfill material comprised of a suitable polymer is introduced in the gap between the flip-chip and the substrate. The underfill also serves to equalize stress placed on the flip-chip and substrate, helps transfer heat from the flip-chip and helps protect the bump connections located between the flip-chip and the substrate from contaminants such as moisture, chemicals, and contaminating ions.
In practice, the underfill material is typically dispensed into the gap between the flip-chip and the substrate by injecting the underfill along two or more sides of the flipchip with the underfill material flowing, usually by capillary action, to fill the gap. For example, U.S. Pat. No. 5,218,234 to Thompson et al. discloses a semiconductor device assembly whereby an epoxy underfill is accomplished by applying the epoxy around the perimeter of the flip-chip mounted on the substrate and allowing the epoxy to flow underneath the chip. Alternatively, the underfill can be accomplished by backfilling the gap between the flip-chip and the substrate through a hole in the substrate beneath the chip
However, the traditional method of underfilling by way of capillary action has a serious disadvantage. The small gap formed between the flip-chip and substrate to which it is connected prevents filling the gap in a uniform manner. Such non-uniform underfilling is particularly prevalent in the areas surrounding the bumps interconnecting the flip-chip to the substrate. When underfilling a flip-chip on a substrate situated in a substantially horizontal plane, the underfill material will generally be non-uniform in character and contain bubbles, air pockets, or voids therein. This non-uniform underfill decreases the underfill material's ability to protect the interconnections between the flip-chip and substrate and environmentally compromises the flip-chip itself, thereby leading to a reduction in the reliability of the chip.
A different method of bonding a semiconductor chip to a substrate is disclosed in U.S. Pat. No. 5,385,869 to Liu et al. whereby the gap between the semiconductor chip and substrate is underfilled utilizing a substrate having a through hole formed therein which is centrally located below the semiconductor chip mounted thereon. The through hole has gates or notches formed at each corner thereof which extend beyond the semiconductor chip, which is mounted thereover. Underfilling the gap between the semiconductor chip and the substrate is accomplished by blocking one side of the through hole, applying an encapsulation material on top of and around the chip, and allowing the encapsulation material to flow into the through hole by way of the gates or notches in the substrate.
As disclosed in U.S. Pat. No. 5,203,076 to Banerji et al., a vacuum chamber is used to underfill the gap between a semiconductor chip and a substrate. A bead of underfill polymeric material is provided on the substrate about the periphery of the chip. Next, the semiconductor chip and substrate are placed within a vacuum chamber with a vacuum being subsequently applied to the chip and the substrate to evacuate the gap therebetween. Air is then slowly allowed to re-enter the vacuum chamber to force the underfill material into the gap between the semiconductor chip and the substrate.
Although the underfill methods disclosed in the Liu and Banerji patents attempt to address the problem of underfilling in a non-uniform manner, those references present solutions that require specialized substrates, use additional equipment in the underfillillg process and increase the cost of production. For example, implementation of the underfilling method illustrated in the Liu reference requires the use of a specialized substrate having a through hole therein. Similarly, the underfilling method illustrated in the Banerji et al. reference requires the use of specialized equipment in the form of a vacuum chamber.
Therefore, it would be advantageous to develop a method for performing underfill of semiconductor chips which results in underfill material that is uniforn and substantially free of voids or air. It would be a further improvement to develop a method for performing uniform underfilling of the gap between the flip-chip and substrate that is cost effective and utilizes standard substrates.
SUMMARY OF THE INVENTION
The present invention is directed to an improved method and apparatus for underfilling the gap between a semiconductor device (flip-chip) and substrate. The improved method of attaching a semiconductor device to a substrate begins with the step of electrically connecting the semiconductor device to the substrate. Next, one end of the substrate is elevated to a position where the substrate and semiconductor device are located on an inclined or tilted plane. Finally, an underfill material is introduced along the sidewall of the semiconductor device located at the elevated end of the inclined substrate with the underfill flowing into and filling the gap formed between the substrate and the semiconductor device.
The improved method of the present invention may include the step of using a suitable dam or barrier located adjacent to the lower edge of the inclined substrate, the lowest point of the inclined substrate. The suitable dam or barrier prevents the underfill material from spreading beyond the sidewalls of the semiconductor device, particularly in instances where the substrate is inclined at a steep angle with respect to a horizontal plane
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The advantages, as well as other novel and important features of the present invention will be better understood when the following description is read along with the accompanying drawings of which:
FIG. 1 is a cross-sectional view of a preferred underfill dispensing step for a semiconductor device, a bumped flip-chip, and an inclined substrate in accordance with the present invention;
FIG. 2 is a cross-sectional view of another preferred underfill dispensing method. which illustrates the placement of a dam or suitable barrier, a fence, located adjacent the substrate;
FIG. 3 is a side view illustrating the placement of the semiconductor device. bumped flip-chip, and substrate of FIG. 1 on top of a support member having a vibrator attached thereto;
FIG. 4 is a top view of a semiconductor device, bumped flip-chip, and an inclined substrate illustrating the use of two suitable barriers, dams or fences, to perform the underfill step,
FIG. 5 is a cross-sectional view of another embodiment of the present invention, illustrating a backfill method of underfilling the gap formed between a semiconductor device, bumped flip-chip, and a substrate,
FIG. 6 is a cross-sectional view of another embodiment of the present invention, illustrating a backfill method of underfilling the gap formed between a semiconductor device, a bumped flip-chip, and a substrate without the use of dams, and
FIG. 7 is a cross-sectional view of another embodiment of the present invention, illustrating a backfill method of underfilling the gap formed between a semiconductor device, a bumped flip-chip, and a substrate wherein the substrate is inverted during the underfilling process.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a substrate or chip carrier 10 is shown for connecting a semiconductor device or flip-chip 12 by conventional direct chip bonding techniques. Substrate 10 is typically made of ceramic, silicone, glass, and combinations thereof Substrate 10 is preferably comprised of a printed circuit board (PCB) or other carrier, which is used in flip-chip technology, such as an FR 4 PCB. Substrate 10 has a front end 14 , a rear end 16 , and a top surface 18 , the top surface 18 having contact pads thereon.
Flip-chip 12 has a front sidewall 30 , a rear sidewall 32 , and an active surface 20 . The active surface 20 comprises integrated circuitry and a plurality of contact pads 22 . The contact pads 22 have bumps 24 thereon, which provide both electrical and mechanical connection to substrate 10 .
An electrical assembly is produced by placing and securing the flip-chip 12 on the top surface 18 of substrate 10 having active circuitry thereon. Specifically, the bumps 24 are aligned with the contact pads of the active circuitry located on top surface 18 of substrate 10 . The flip-chip 12 is then electrically and mechanically connected to the substrate 10 by curing or reflowing the bumps 24 , depending upon the type of material comprising the bumps 24 . Alternatively, the bumps 24 may be formed on the substrate 10 prior to attachment of the flip-chip. In other words, either surface may bear the bumps thereon. Although bumps 24 are typically formed with solder, it is understood that any other materials known in the art (e.g. gold, indium, tin lead, silver or alloys thereof) that reflow to make electrical interconnects to substrate 10 can also be used. Additionally, the bumps 24 may be formed of conductive polymeric and epoxy materials and may include various metals being plated thereon.
After reflowing of the bumps 24 , a space or gap 26 is formed between the active surface 20 of flip-chip 12 and the top surface 18 of substrate 10 . The size of the gap 26 is controlled by the size of the reflowed solder bumps and typically varies from approximately 3 to about 10 mils.
Next, an underfill material 28 is applied to fill the gap 26 between the flip-chip 12 and the substrate 10 . As previously stated, the purpose of the underfill material 28 is to environmentally seal the active surface 20 of the flip-chip 12 and the bumps 24 , to help provide an additional mechanical bond between the flip-chip 12 and the substrate 10 to help prevent and/or distribute stress on the flip-chip 12 and bumps 24 and to help transfer heat from the flip-chip 12 . The underfill material is typically a polymeric material, such as an epoxy or an acrylic resin, and may contain inert filler material therein. The underfill material 28 typically has a thermal coefficient of expansion that approximates that of the flip-chip 12 and/c the substrate 10 to help minimize stress placed on either the flip-chip 12 or the substrate 10 during the operation of the flip-chip caused by the heating of the underfill material 28 . To promote filling of the gap between the substrate 10 and flip-chip 12 , the viscosity of the underfill material 28 is controlled, taking into account the flow characteristics of the underfill material, the material characteristics of the substrate 10 , the material characteristics of the flip-chip 12 , and the size of the gap.
As shown, the underfill process is started by elevating or inclining the front end 14 of the substrate 10 in order to position the substrate 10 on an inclined plane 2 with respect to a horizontal plane 1 . The angle of elevation or inclination of the inclined plane 2 and the attendant substrate 10 and flip-chip 12 is dependent on the viscosity or the rate of dispensing of the underfill material 28 The viscosity of the underfill material 28 should be adjusted to allow facile flow of the underfill material 28 but should be left low enough to readily prevent the flow of the underfill material 28 beyond the perimeter of the flip-chip 12 . It should also be understood that the substrate 10 may be inclined by placing the substrate 10 on a support member 44 , such as a tilted table or conveyor belt, as is shown in FIG. 3 and further described below. Alternately, the substrate 10 may be inclined by placing the substrate 10 below a support member or horizontal plane 1 as described hereinbelow.
Underfilling is accomplished by applying the underfill material 28 under the front sidewall 30 of flip-chip 12 and allowing it to flow between the flip-chip 12 and the substrate 10 and around the bumps 24 . The underfill material 28 is applied with an underfill dispenser 34 , such as a syringe having a suitable nozzle thereon or any other dispensing means known in the art.
As shown, since the substrate 10 having flip-chip 12 thereon is placed on an incline, in addition to any fluid pressure used to inject the underfill material and any capillary action force acting on the underfill material, a gravitational force also acts on the underfill material, causing the underfill material 28 to readily flow from front sidewall 30 toward rear sidewall 32 . Due to the additional action of the gravitational force to that of the injection pressure and capillary action air pockets, bubbles, and voids found within the underfill material 28 are displaced by the denser underfill material 28 as it flows toward the rear sidewall 32 of flip-chip 12 . The ability to displace and the speed of displacement of the voids is dependent on the inclined angle of the substrate 10 having flip-chip 12 thereon, the viscosity of the underfill material 28 , the injection rate of the underfill material 28 , and the uniformity of the injection of the underfill material 28 into the gap between the substrate 10 and the flip-chip 12 to form a substantially uniform flow front of underfill into and through the gap. If desired, the process of underfilling the gap may be repeated by inclining the substrate 10 in the opposite direction and subsequently dispensing another amount of underfill material 28 from an opposing side of the flip-chip 12 into the gap to improve the uniformity of the underfill material 28 filling the gap.
After application of the underfill material 28 , the material is cured either by heat, ultraviolet light, radiation, or other suitable means in order to form a solid mass.
Referring now to FIG. 2, a second embodiment of an interconnected flip-chip 12 and substrate 10 is shown. As shown, a dam or barrier 40 is used on the top surface 18 of the substrate 10 to help contain the flow of the underfill from the gap at the rear sidewall 32 of the flip-chip 12 . Conventional molding equipment and techniques (e.g pour molding, injection molding, adhesive bonding, etc.) can be used to form the dam 40 on the substrate 10 . The dam 40 is typically formed from any suitable epoxy resin material compatible with the substrate I 0 .
The dam 40 extends upwards from and is substantially perpendicular to the top surface 18 of the substrate 10 . As shown, the dam 40 may be seen to lay substantially parallel and slightly aft the rear sidewall 32 of the flip-chip 12 .
The dam 40 limits the expansion or gravitational flow of the underfill material 28 beyond the position of the dam 40 During the underfill procedure, the underfill material 28 coats and spreads out onto the surfaces of the flip-chip 12 and substrate 10 . The dam 40 prevents the spread of underfill material 28 beyond the rear sidewall 32 of the flip-clip 12 by means of surface tension.
Additionally, use of the dam 40 (as opposed to using no dam) permits use of lower viscosity underfill materials, if so desired, during the underfill procedure. The underfill material may be easily controlled and a wider range of viscosities may be used by controlling the depth of the dam 40 and by controlling the width between the rear sidewall 32 of the flip-chip 12 and the dam 40 . Use of the dam 40 also permits tilting the substrate 10 at a greater angle of elevation with respect to the horizontal plane 1 in order to accelerate the underfill process or to permit the use of higher viscosity underfill materials should such a need arise. Furthermore, if desired, a dam 40 may be used on all three sides of the flip-chip 12 located on the substrate 10 except the side of the flip-chip 12 from which the underfill material 28 is being dispensed.
Referring to FIG. 3, a side view of a flip-chip 12 and substrate 10 , interconnected via bumps 24 , of a third embodiment of the invention is shown. The substrate 10 is inclined with respect to a horizontal plane I by placing the substrate 10 onto a support member 44 . Support member 44 can be a tilt table, a tilted conveyor belt, or any other means of support suitable for holding the substrate 10 of the present invention. Preferably, support member 44 can be positioned and locked at various angles and can also be elevated or lowered from front to back as well as side to side.
Attached to the support member 44 is a vibrator 48 . The vibrator 48 facilitates and hastens the displacement of air pockets and voids by the underfill material 28 during the previously described underfill process. The action of the vibrator 48 also permits the use of higher viscosity underfill materials and/or permits underfilling with the support member 44 positioned at a gradual slope.
Referring to FIG. 4, a top view of an interconnected solder-bumped 24 flip-chip 12 and substrate 10 of a fourth embodiment of the present invention is shown similar to that of the second embodiment as shown in FIG. 2 . However, this particular embodiment illustrates the use of two dams 40 and 40 ′, which are oriented transversely with respect to one another. The two dams 40 and 40 ′ lie in substantially parallel orientation with respect to two mutually perpendicular and abutting sidewalls 50 and 52 of the flip-chip 12 .
The method of this embodiment permits underfilling along two sidewalls 54 and 56 simultaneously. Dams 40 and 40 ′ prevent the spread and overflow of underfill material 28 beyond sidewalls 50 and 52 of the flip-chip 12 . The underfill material may be easily controlled and a wider range of viscosities may be used by controlling the depth of the dams 40 and 40 ′ by controlling the width between the sidewalls 50 and 52 of the flip-chip 12 and the dams 40 and 40 ′, and by controlling the distance between the corners 60 and 60 ′ of the dams 40 and 40 ′.
An alternative method comprises tilting the substrate 10 so as to elevate sidewall 54 and applying the underfill material 28 under sidewall 54 via the underfill dispenser 34 ′. The substrate 10 is then tilted so as to elevate sidewall 56 and the underfill material 28 is dispensed along sidewall 56 via underfill dispenser 34 . This alternating underfill technique can be repeated until the underfill material 28 is free of air pockets and voids.
Referring to FIG. 5, a cross-sectional view of an interconnected solder-bumped 24 flip-chip 12 and substrate 10 of a fifth embodiment of the present invention is shown midway through the underfill process. In this particular embodiment, the substrate 10 has a suitably shaped opening 60 situated near the center of the substrate 10 through which underfill material 28 can be applied via the underfill dispenser 34 . Additionally, dams 40 and 40 ′ located on each side of the flip-chip 12 are molded or suitably attached to top surface 18 of the substrate 10 , as described hereinbefore, being positioned to lay slightly beyond first and second sidewalls, rear sidewall 32 , and front sidewall 30 , respectively. It should also be understood that other dams 40 ′ (not shown) are located on the first and second lateral sidewalls of the flip-chip 12 to confine the underfill.
Referring to drawing FIG. 6, a cross-sectional view of an interconnected solder-bumped 24 flip-chip 12 and substrate 10 of a sixth embodiment of the present invention is shown midway through the underfill process. In this particular embodiment, the substrate 10 has a suitably shaped opening 60 situated near the center of the substrate 10 through which underfill material 28 can be applied via the underfill dispenser 34 . In this instance, there is no dam used to confine the underfill material 28 . Additionally, if desired, the substrate 10 having flip-chip 12 located thereon may be tilted in each direction to enhance the flow of the underfill material 28 in the gap 26 between the substrate 10 and the flip-chip 12 during the underfilling process
Referring to drawing FIG. 7, a cross-sectional view of an interconnected solder-bumped 24 flip-chip 12 and substrate 10 of a seventh embodiment of the present invention is shown midway through the underfill process. In this particular embodiment, the substrate 10 has a suitably shaped opening 60 situated near the center of the substrate 10 through which underfill material 28 can be applied via the underfill dispenser 34 Additionally, dams 40 and 40 ′ located on each side of the flip-chip 12 are molded or suitably attached to top surface 18 of the substrate 10 , as described hereinbefore, being positioned to lay slightly beyond first and second sidewalls, rear sidewall 32 , and front sidewall 30 , respectively. It should also be understood that other dams 40 ′ (not shown) are located on the first and second lateral sidewalls of the flip-chip 12 to confine the underfill. In this instance, the substrate 10 having flip-chip 12 located thereon is inverted during the underfill process so that the underfill material 26 is dispensed through the opening 60 into the gap 28 between the substrate 10 and flip-chip 12 . As in the previous embodiments, the substrate 10 is located at an angle with respect to horizontal plane 1 , although located therebelow and inclined with respect thereto.
In operation, the present method is initiated by elevating or inclining front end 14 of the substrate 10 . As the underfill material 28 is added, in this case by means of an opening 60 through the substrate 10 , the underfill material 28 flows towards the dam 40 and fills the lowered portion of the gap 26 between the flip-chip 12 and the substrate 10 . The front end 14 of the substrate 10 is then lowered and the rear end 32 of the substrate 10 is elevated. The backfill method is then repeated with the underfill material 28 now flowing towards the dam 40 ′ to complete the filling of the gap 26 between the flip-chip 12 and the substrate 10 The underfill material 28 is then cured, as previously described. Alternately, the underfill material 28 may be cured after the partial filling of the gap between the substrate 10 and flip-chip 12 , the remainder of the gap filled and subsequently cured.
While the present invention has been described in terms of certain methods and embodiments, it is not so limited, and those of ordinary skill in the art will readily recognize and appreciate that many additions, deletions and modifications to the embodiments described herein may be made without departing from the scope of the invention as hereinafter claimed.
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A method and apparatus for attaching a semiconductor device to a substrate. One end of the substrate is elevated to position the substrate and the coupled semiconductor device on an inclined plane. An underfill material is introduced along a wall of the semiconductor device located at the elevated end of the inclined substrate with the underfill material being placed between the substrate and the semiconductor device. An optional but preferred additional step of the invention includes coupling a barrier means to the substrate at a point on the substrate adjacent to a sidewall of the semiconductor device located at the lowest point of the slope created by the inclined substrate. The barrier means prevents the underfill material from spreading beyond the sidewalls of the semiconductor device, particularly in instances where the substrate is inclined at a steep angle.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 09/566,183, filed May 5, 2000.
FIELD OF THE INVENTION
[0002] The invention relates to apparatus and methods to be utilized for the gasification of halogenated materials, and in particular to apparatus and methods that efficiently produce useful end products such as anhydrous or highly concentrated hydrogen halide and/or synthesis gas.
BACKGROUND OF THE INVENTION
[0003] Related inventions include a prior patent application for a Method and Apparatus for the Production of One or More Useful Products from Lesser Value Halogenated Materials, PCT international application PCT/US/98/26298, published 1 Jul. 1999, international publication number WO 99/32937. The PCT application discloses processes and apparatus for converting a feed that is substantially comprised of halogenated materials, especially by-product and waste chlorinated hydrocarbons as they are produced from a variety of chemical manufacturing processes, to one or more “higher value products” via a partial oxidation reforming step in a gasification reactor. Other related inventions include six co-filed applications for certain other aspects of the process for gasifying halogenated material, such aspects including apparatus and methods for reactor vessel designs, gasifier nozzle designs, controlling aerosols, producing high quality acids, particulate removal and quench vessel designs.
[0004] A gasification reaction process for halogenated materials is a technology for consuming halogenated material byproducts and waste streams, most likely liquid chlorinated organic byproducts and waste streams, and for producing substantially useful products therefrom. Successful implementation of the technology may replace liquid thermal oxidation facilities which represent the current industry technique for treating such waste and byproduct streams. Gasification offers several advantages over thermal oxidation including more economic costs, reduced emissions and the capture of maximal chemical value from the feed stream constituents. Gasification is also more flexible than the competing technologies in that it has a significantly broader range of acceptable feedstock composition.
[0005] In a gasification process for halogenated materials, a source of oxygen (in gaseous form) is mixed with a source of one or more halogenated material feeds (typically in liquid form and pre treated or pre processed if necessary or desirable), the mixture taking place in at least one gasification reactor to produce syngas. The syngas typically comprises a hydrogen halide, CO and H 2 with residual C, CO 2 , H 2 O and trace elements.
[0006] Such gasification in a reactor occurs at partial oxidation conditions, i.e. at oxygen to fuel ratios that are substoichiometric with reference to complete combustion. Under such conditions carbon particles or soot can be formed as a side product. This soot requires additional capture and treatment steps downstream in the process, thereby decreasing the economic efficiency of the process as a whole. One goal of the instant invention is to operate the gasification process more optimally while managing parameters such as pressure, temperature, reactants and flow rates so that the production of C (carbon particles or soot), CO 2 and H 2 O is minimized. Higher oxygen to fuel ratios can reduce the formation of soot. However, oxygen to fuel ratios are limited by permissible flame temperatures.
[0007] In various processes for gasifying essentially hydrocarbonaceous fuels or waste products, steam is known to be used as a gasifying agent. Under suitable conditions steam is known to react with carbon (or carbonaceous waste products or soot) to convert the carbon to carbon monoxide and the steam to hydrogen, both carbon monoxide and hydrogen being desirable products. Steam is also known to be used as a “moderator” in regard to several functions in the environment of gasifying hydrocarbonaceous materials. The addition of steam “moderates” flame temperatures, allowing higher oxygen to fuel ratios to be utilized. Higher oxygen to fuel ratios, as mentioned above, can reduce the formation of soot due to a higher partial pressure of oxygen.
[0008] Steam is also known to be used in gasification processes for essentially hydrocabonaceous materials for adjusting the hydrogen to carbon monoxide ratio of a product synthesis gas to meet the requirements of downstream customers.
[0009] In the process of the gasification of hydrocarbonaceous materials, however, unlike in the instant gasification process, excess water created by used steam can be purged as waste water from downstream unit operations with a near negligible loss of valued products. In the gasification process of halogenated organic materials, the situation is otherwise. While the addition of steam to the gasification reactor can have the same beneficial effects mentioned above (of reducing soot and allowing higher oxygen to fuel operating ratios and supplying additional hydrogen,) the addition of steam can be wasteful. If the halogenated organic gasification process includes the production of a hydrogen halide to an anhydrous form, or even to a highly concentrated aqueous solution, the purge of the excess water can result in the loss of valuable product. In both processes, excess steam or water must be purged from the system downstream to maintain a water balance. In the case of the production of anhydrous or concentrated hydrogen halides, the purge step contains a significant concentration of the hydrogen halide. This loss is in proportion to the amount of steam moderator furnished to the gasifier.
[0010] The present invention teaches a method to close the water balance in the halogenated organic gasification process while significantly minimizing the loss of valuable hydrogen halide product in an aqueous purge. More particularly, a gasification process for halogenated materials, if separated hydrogen halide is anticipated to be sold as an anhydrous product or in a highly concentrated solution, includes a distillation step to separate hydrogen halide product from water (in particular from water absorbed when hydrogen halide gas passes through an absorber stage). The present invention teaches the use of a vapor side-draw from the distillation stage wherein water/hydrogen halide vapor is extracted and recycled to the gasifier as a “moderator” steam stream. The distillation system can be run at a pressure higher than the gasifier, thereby providing pressure to straightforwardly feed the extracted water/hydrogen halide vapor into the gasifier. Optionally, to help avoid liquid carryover in the “moderator” stream to the gasifier, the water/hydrogen halide vapor stream can be superheated with an appropriate heat source, such as steam, a heat transfer fluid, or the like.
[0011] The recycled vapor from the distillation step is principally water vapor but contains significant amounts of hydrogen halide. The hydrogen halide recycles through the gasifier to be subject to recapture again in the hydrogen halide recovery stage. The water vapor or steam is primarily consumed via gas shift reactions and carbon consuming reactions, discussed above. In such manner, the water balance of the process is maintained or completed while also achieving the desired objective of soot reduction. A combination of steam as well as recycled vapor can be utilized in whatever ratio needed in order to match and achieve the process water balance, as necessary. Recycled vapor with or without steam can also be used to adjust H 2 to CO ratio of the product syngas.
[0012] Moderator streams are typically supplied to a gasification reactor through a suitably designed burner for intimate and appropriate mixing of all reactants. Lipp et al. describes one such burner system in a co-filed and co-pending patent application entitled Method and Apparatus for a Feed Nozzle for a Gasification Reactor for Halogenated Materials.
[0013] An alternate methodology of the present invention teaches the use of another moderator, either together with or in lieu of the water/hydrogen halide vapor moderator, for helping to drive and to maintain the water balance of the gasification reactor process. As discussed above, synthesis gas created from the gasification of halogenated organics contains carbon dioxide. Methods for the removal and capture of carbon dioxide from synthesis gas are known. Carbon dioxide has some of the same reforming tendencies as steam. That is, carbon dioxide reacts with carbon and soot particles to produce carbon monoxide at gasification conditions. It is another aspect of the present invention that the carbon dioxide produced in the synthesis gas reaction can be captured and recycled as an alternate or further moderator, augmenting or displacing steam. Some water vapors are produced due to the gas shift reaction, e.g. CO+H 2 O<—>CO 2 +H 2 . The use of carbon dioxide as a moderator and/or a combination of steam and carbon dioxide thus further allows the process water balance to be managed without purging or losing hydrogen halide in an aqueous discharge. It can also be used to adjust H 2 to CO ratio in the product syngas. Depending on the operating pressure of the carbon dioxide recovery system, carbon dioxide can be pressured back to a gasifier reactor or a compression operation can be included for pressurizing the CO 2 stream to suitable pressures for feed to the gasifier. Alternately, carbon dioxide can be purchased and stored as a commodity. Carbon dioxide, thus stored can be supplied at appropriate pressure to the gasifier.
[0014] As discussed above, while it is known in current gasification practice for conventional hydrocarbonaceous materials to use steam, and to a lesser extent carbon dioxide, to minimize soot formation and to adjust hydrogen to carbon monoxide ratios in the product syngas for intended consumers, the instant invention improves upon the above in that the “moderator” is or can be a recycled process fluid. Such use of the recycled process fluid prevents loss otherwise of hydrogen halide mixed into a purged water vapor process fluid. Using a recycled water/hydrogen halide vapor as a moderator provides a means for controlling the water balance of the process with the additional advantage of minimizing the aqueous waste volume discharged from the plant and minimizing the loss of product. As a further advantage, by providing a method for managing water balance, using a recycled water/hydrogen halide vapor as a moderator permits the use of higher water addition rates to a hydrogen halide absorption column. Use of higher water addition rates to a hydrogen halide absorption column for the synthesis gas creates a higher recovery efficiency of hydrogen halide.
[0015] Recycling the purged water/hydrogen halide vapor as a moderator should have the further advantage of also permitting efficient utilization of a wider array of feed stock compositions. That is, feed stocks with a lower halide content can be processed while still producing anhydrous or highly concentrated hydrogen halide product since the loss of hydrogen halide has been lowered. Said otherwise, without use of the water/hydrogen halide vapor as a recycled moderator in the gasification reactor, recovered aqueous hydrogen halide from low halide feed concentration materials might be unsuitable for anhydrous recovery because of the otherwise excessive halide loss through aqueous discharge.
[0016] The instant invention has a further advantage of requiring no additional significant equipment, except perhaps a vapor superheater. Generation of the water/hydrogen halide vapor and its recycling can be easily integrated into the distilling system. Whether anhydrous or aqueous hydrogen halide product is desired, recycling water/hydrogen halide vapor from a distillation stage allows the production of more concentrated solutions by managing water balance without loss of product. Further, for feed stocks lean on hydrogen, the recycled water/hydrogen halide vapor serves as an additional source of hydrogen for converting all halide to a hydrogen halide component.
SUMMARY OF THE INVENTION
[0017] The present invention offers improved methods for a gasification process for halogenated materials. The improvements include one or more of the following goals: increasing the efficiency of the process; increasing and/or maximizing the anhydrous hydrogen halide recovery; minimizing the aqueous discharge; and adjusting the H 2 to CO ratio.
[0018] The present invention includes apparatus and methods for increasing the efficiency of a gasification process for halogenated materials. The invention in one embodiment includes removing water/hydrogen halide vapors from a distillation stage of a gasification process and recycling the vapor as a reactant and/or moderator feed to a gasification reactor stage of the process.
[0019] The method includes managing pressure, temperature and flow rate of the water/hydrogen halide vapor to control water balance, to lower carbon particle soot output and to moderate flame temperature in the gasification reactor. The method and apparatus include alternately or additionally capturing carbon dioxide from synthesis gas produced by a gasification of halogenated materials, or otherwise securing carbon dioxide, and feeding the carbon dioxide as a reactant and/or moderator gas to a gasification reactor stage of the process. The carbon dioxide may be added in addition to or in lieu of a water/hydrogen halide vapor moderator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] A better understanding of the present invention can be obtained when the following detailed description of the preferred embodiment is considered in conjunction with the following drawings, in which:
[0021] [0021]FIGS. 1A and 1B illustrate block flow diagrams for a gasification process for halogenated materials; FIG. 1A illustrates recycling water/hydrogen halide vapor while FIG. 1B illustrates recycling captured CO 2 .
[0022] [0022]FIGS. 2A and 2B illustrate in more detail a gasifier stage for a gasification process of FIGS. 1.
[0023] [0023]FIG. 3 illustrates a quench and solids removal stage of a gasification process of FIG. 1.
[0024] [0024]FIGS. 4A and 4B illustrate an absorber and an aqueous acid cleanup stage of a gasification process of FIGS. 1.
[0025] [0025]FIG. 5 illustrates an anhydrous distillation stage of a gasification process of FIGS. 1.
[0026] Tables 1A and 1B illustrate a numerical simulation of a run of a gasification reactor for halogenated materials demonstrating sensitivity of the outlet gas composition to varying the moderator flow rate.
[0027] Tables 2A, 2B and 2C illustrate parameters for a commercially available system for the capture of carbon dioxide from syngas.
[0028] Tables 3A-3E show, from a mathematical model, heat and material balances, demonstrating balancing of the water across a plant by recycling of the water.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0029] An embodiment for a gasification process for halogenated materials is indicated in block diagram form in FIGS. 1A and 1B. FIG. 1A illustrates an embodiment of the process in which water/hydrogen halide vapors 530 (assumed for the purpose of the embodiment to be H 2 O/HCL) are recycled from a distillation unit 500 back to a gasifier 200 , in a first aspect of the present invention. FIG. 1B illustrates an embodiment of the invention wherein syngas produced from a gasifier 200 is finished in a gas finishing stage 700 and is further processed in a CO 2 recovery stage 700 ′, for carbon dioxide recovery and the carbon dioxide stream 730 is recycled back to gasifier 200 . Of course, a preferred embodiment could provide for both recycling of carbon dioxide and water/hydrogen halide vapors. Further, carbon dioxide could be purchased and/or stored as opposed to, or in addition to being captured in a recovery stage.
[0030] More particularly, FIGS. 2 - 5 illustrate in more detail aspects of an embodiment of a gasification process for halogenated materials than are indicated in block diagram form in FIGS. 1A and 1B. Elements of FIGS. 2 and 5, in particular, will be discussed in detail to illustrate preferred embodiments of the instant invention and to place the instant invention in perspective.
[0031] [0031]FIGS. 2A and 2B illustrate a gasifier 200 in accordance with a preferred embodiment. The particular gasifier design of FIGS. 2A and 2B has two stages, primary gasifier R- 200 and secondary gasifier R- 210 for converting a fuel comprised substantially of halogenated materials to reaction products including hydrogen halide and synthesis gas components. For the purpose of this discussion the halogenated material will be assumed to be comprised of chlorinated hydrocarbons (RCL's). In FIG. 2A, RCL liquid stream 144 is atomized in primary reactor R- 200 with a pure oxygen stream 290 and a steam stream 293 , both injected through a main burner or nozzle BL- 200 . In the harsh gasification environment inside gasification reactor R- 200 , the RCl components are partially oxidized and converted to synthesis gas (syngas) comprised primarily of carbon monoxide, hydrogen, hydrogen chloride, and of lesser amounts of water vapor and carbon dioxide, as well or of some undesirable side products such as soot or carbon. The syngas flows into secondary reactor R- 210 to allow all reactions to proceed to completion, thus yielding very high destruction efficiencies of all species and minimizing undesirable side products such as soot. The output is syngas stream 210 .
[0032] Because of the corrosive nature of HCl, both as a hot, dry gas and as a condensed liquid, the reactor shells and connecting conduit are shown jacketed with a closed heat transfer fluid system for wall temperature control, as indicated in FIGS. 2A and 2B in combination, which system comprises the subject of a related invention, filed simultaneously hereto. FIG. 2B illustrates a temperature control fluid circulating system to control the temperature of a pressure vessel wall of a gasifier, the fluid flowing between a pressure vessel wall and a jacket.
[0033] The primary gasifier R- 200 of the instant embodiment functions to atomize the liquid fuel, evaporate the liquid fuel, and thoroughly mix the fuel with oxygen, moderator, and hot reaction products. The gasifier burner or nozzle design forms the subject of a related invention, filed simultaneously hereto. The gasifier R- 200 of the preferred embodiment operates at approximately 1450° C. and 75 psig. These harsh conditions insure near complete conversion of all feed components.
[0034] The reactions that take place in gasifier R- 200 are many and complex. The reaction pathways and kinetics are not completely defined nor understood. Indeed, for the numerous species that comprise the anticipated gasifier feeds, the multiple reactions and their kinetics for each will be somewhat different. However, because of the extreme operating conditions in the gasifier, the reactions can be fairly represented by the overall reactions as defined below, in a close approach to equilibrium for most species.
[0035] RCl Partial Oxidation:
[0036] Chlorinated organics are partially oxidized to CO, H 2 and HCl.
C v H w Cl y +( v/ 2)O 2 →( v )CO+[( w−y )/2]H 2 =( y )HCl
[0037] However, since the gasifier operates with a slight excess of oxygen above this stoichiometry, further oxidation occurs. Water vapor and carbon dioxide can also participate as oxidizers at gasification conditions.
C v H w Cl y +CO 2 →( v+ 1)CO+[( w−y )/2)]H 2 +( y )HCl
C v H w Cl y +H 2 O→( v )CO+[1+( w−y )/2]H 2 +( y )HCl
[0038] Further oxidation reactions:
CO+½O 2 →CO 2
H 2 +½O 2 →H 2 O
[0039] The oxidation reactions with oxygen, including the reaction C v H w Cl y +(v/2)O 2 →(v)CO+[(w−y)/2]H 2 =(y)HCl, are highly exothermic, and thus provide the energy for driving the other reactions, maintaining the gasifier temperature as desired.
[0040] Thermal Decomposition Reactions:
[0041] In local fuel rich zones resulting from the less than perfect mixing inherent to any burner, thermal decomposition occurs in the absence of oxygen or oxidizing species.
C v H w Cl x →C r +( x )HCl+( v−r )CH 4 +[w−x− 4*( v−r )/2]H 2
[0042] where C is soot, and methane CH 4 is the simplest hydrocarbon molecule which is quite stable.
[0043] Gas Shift Reactions:
[0044] CO+H 2 O⇄CO 2 +H 2 , classic gas shift reaction, driven primarily by gas composition, pressure and temperature have limited effect within the narrow opening range of the gasifier.
[0045] CH 4 +H 2 O⇄CO+3H 2 , steam—methane reforming driven almost completely to the right at gasifier conditions.
[0046] Soot is also subject to partial oxidation reactions as described in paragraph 1 above, excluding the chlorine atom.
[0047] Other Reactions:
[0048] Due to the low partial pressure of oxygen in the gasifier, essentially all halogens, including chlorine as shown above, equilibrate to the hydrogen halide.
[0049] Operating temperature in the gasifiers R- 200 and R- 210 should not be allowed to drop below approximately 1350° C. Conversion efficiency is reduced at lower temperatures. Because of accelerated corrosion attack to the refractory system, the gasifier temperature should not be allowed to exceed 1500° C. Conversion efficiency is very high at 1450° C. and only limited gains are made at higher temperatures, not justifying the accelerated refractory corrosion. Preferably, no RCl or liquid fluid is introduced to the gasifier until it is preheated to an acceptable operating temperature. Reactor temperature is actually controlled on a cascade loop with oxygen/fuel ratio. As described above, the oxidation reactions provide the heat to drive reactor temperature. The 0 2 /fuel ratio will therefore be increased or decreased as necessary to adjust reactor temperature to the targeted value. This ratio must be carefully controlled because of the sensitivity in using pure oxygen where small increments can cause significant temperature changes. The control band must also be limited to approximately one-half of the stoichiometric oxygen/fuel ratio to insure that the flammable mixture (syngas) environment in the gasifier is always maintained in a reducing state. Hazardous deflagrations can occur if excess oxygen is introduced to the fuel rich reactor chamber. Target oxygen to fuel ratio for the base feedstock is 0.489 lb of oxygen per 1.0 lb of liquid fuel. This will of course vary as the feed composition changes and if moderator flow is varied.
[0050] Not only steam stream 293 but also, or alternately, an HCl/water vapor mixture stream 530 from a desorber T- 510 (FIG. 5) can be used as moderator flow. The moderator flow can be used to temper the flame temperature of the pure oxygen/fuel burner. This moderator can also serve as a coolant flow for the burner. Depending on the heating value of the liquid fuel, pure oxygen and the fuel can operate at the target gasifier temperature with insufficient oxygen to complete the partial oxidation reactions. This results in decreased conversion efficiency, increased soot. To correct this deficiency, moderator flow can be increased, thus permitting additional oxygen while maintaining the target gasifier temperature within limits. Moderator flow can be increased until sufficient oxidant is present to complete the desired reactions. In practice this can be defined by the concentration of fully oxidized species in the exit gas. For example, CO 2 and H 2 O may be targeted to be no less than 1.0 volume % each in the exit gas, and values as high as 10-15% vol. may be acceptable for heavy sooting or poor converting feedstocks. Steam as a moderator flow should be limited as possible because it does put additional load on the plant water balance and decreases the concentration of aqueous HCl absorbed downstream.
[0051] The burner BL- 200 is an integral and vital component of a primary gasifier. The discharge jet from the burner provides a momentum source for mixing in a primary gasifier. The main burner should atomize the liquid into this mixing jet. Target atomization performance might be defined as where 99% of the liquid volume is of a droplet size of 500 microns or smaller. This should provide for a sufficient liquid surface area enabling rapid evaporation of the fuel. Two mechanisms play a role in the atomization in preferred embodiments. The preferred embodiments form the subject of a co-filed patent application. In preferred embodiments, liquid is injected through an annular arrangement of orifices centered around a central oxygen discharge. Pressure drop through these orifices initiates coarse atomization of the discrete liquid jets. The orifices, and thus the liquid jets, are directed to intersect out in front of the face of the burner, or more specifically, along the axis of the oxygen discharge, and so intersect with the oxygen discharge jet. The oxygen discharge jet provides a primary energy source for atomization. Static pressure of the oxygen is converted to kinetic energy through the burner nozzle. Preferably the burner provides a supersonic nozzle and so achieves a maximal velocity. The velocity differential between gas and liquid provides an atomization energy which reduces the liquid jet to fine, discrete droplets. Moderator steam may also be mixed with the oxygen upstream of the burner in this particular operating mode. Oxygen to the gasifier is preferably preheated to 120° C. to offset the temperature drop as oxygen is expanded through a supersonic atomizing nozzle, thus increasing atomization efficiency.
[0052] To avoid induction of hot reaction chamber products into a near pure oxygen jet immediately at a burner face, and to avoid the extreme temperature conditions which result, moderator, or some portion thereof, can be jetted into the gasifier as an annular film surrounding the oxygen/fuel jet. This “inert” layer tends to move the hot oxidizing zone out away from the face of the burner, thus reducing the heat flux and resulting temperatures on the burner face.
[0053] [0053]FIG. 2B, as mentioned above, illustrates a temperature control fluid system for reactor vessel wells. This system forms the subject of a separate co-filed patent application. The system can operate to control the wall temperature of the pressure vessels to approximately 200° C., or safely above the dew point of HCl to avoid condensation and resulting in increased corrosion of the pressure vessel wall.
[0054] [0054]FIGS. 3, 4A and 4 B illustrate a quench and solids removal stage 300 of a preferred embodiment of a gasification process and an absorber 400 and aqueous acid 450 cleanup stage of a preferred embodiment of a gasification process. The quench, solids removal absorber and cleanup stages of the preferred embodiment lead to an anhydrous distillation stage 500 of FIG. 5, which is of particular significance to the instant invention. The disclosures of FIGS. 3, 4A and 4 B are included for background purposes and clarification.
[0055] [0055]FIG. 5 illustrates features of a preferred embodiment for an anhydrous distillation process for halogenated materials. The anhydrous distillation area 500 in general consists basically of a distillation system, including desorber T- 510 , with auxiliary equipment to desorb a hydrogen halide stream, treated herein as an HCl stream, from an aqueous (hydrogen halide) HCl stream. A desorber overheads stream 503 in the preferred embodiment of FIG. 5 should comprise essentially a saturated HCl stream (+99 vol. % HCl). This HCl stream 503 can be further processed in one or more condensors, E- 515 and E- 520 , and in an anhydrous HCl drying and compression area 600 , including an HCl drying tower T- 620 . Desorber bottoms from desorber T- 510 , stream 501 , should comprise an azeotropic (˜22 wt. % HCl) aqueous HCl stream which can be recycled to an HCl recovery absorber, illustrated as stream 554 , where it can be reconcentrated to target aqueous acid strength.
[0056] A hydrogen chloride—water system is a highly non-ideal mixture. It forms an azeotrope at approximately 20.0 wt. % HCl at atmospheric pressure. Water has a higher activity coefficient above this concentration. The azeotrope shifts with pressure, decreasing (HCl concentration reference) as pressure increases. The azeotrope is approximately 16.6 wt. % at 59 psig. When an absorber bottoms stream, 483 , 500 ′, enters a desorber T- 510 above the azeotropic concentration in the desorber, HCl is a volatile species and is fractionated overhead.
[0057] In the preferred embodiment of FIG. 5, aqueous acid from storage illustrated as stream 483 and referenced in FIG. 4, can be cross exchanged with the bottoms stream 510 and fed to the HCl desorber T- 510 . The feed is preferably introduced between an upper and lower packed section. The HCl desorber can fractionate HCl overhead while discharging a weak aqueous HCl stream from the bottoms. At preferred base design conditions (100 psig, 45° C. from the secondary condenser E- 520 ) the overheads gas should be about 96 vol. % HCl, 0.12 vol. % H 20 , with small amounts of noncondensibles—primarily CO 2 and to a lesser extent N 2 . Essentially all of the noncondensibles should be driven overhead in the desorber. Column bottoms may operate at approximately 175° C., and an acid concentration of about 22 wt. % HCl could be expected. Condensed liquid from both a primary E- 515 and a secondary E- 520 condenser can be collected in a reflux drum D- 515 and pumped back as, column reflux. A knock-out drum D- 520 after the secondary condenser can also remove free liquid to help prevent its carryover into the anhydrous HCl drying system. The column reboiler E- 510 can be driven by 235 lb. steam. Condensate level on the stream (shell) side of the reboiler can be controlled to manipulate heat transfer surface area, and thus reboiler duty for the column.
[0058] When producing anhydrous HCl, as per the present invention, the water balance is preferably closed by using a sidedraw vapor 514 from a desorber as a moderator for the gasifier. This vapor may be, for instance, about 59 wt % H 20 and 41 wt. % HCl. When operating in this mode, the delivery pressure to a gasifier dictates the operating pressure of the desorber, which is about 100 psig. If no sidedraw vapor is required for the gasifier, operating column pressure can be reduced to 65-75 psig. The advantage of a lower operating pressure is cooler bottoms temperature which results in lower corrosion and permeation rates for the equipment. Boiling HCl as may exist at the bottoms of the desorber can be very aggressive, and milder operating conditions are more favorable to equipment reliability. Bottoms temperature is preferably not allowed to exceed 185° C. due to limitations of the typical impregnated graphite materials of reboiler tubes and the typical Teflon linings for towers and piping.
[0059] The bottoms liquid stream 510 , which is cross exchanged with a desorber feed, can be further cooled to approximately 40° C. (or by using cooling tower E- 550 , which may include use of even sea water) and directed on to a dilute acid drum D- 550 . This drum can serve as a surge volume for the weak acid, which can be pumped back to a middle section of an HCl absorber, illustrated as stream 554 , where it absorbs additional HCl. A small blowdown to an environmental area, illustrated as to neutralizer R- 810 , can be used to control contaminant concentrations if these undesirables (salts, metals, etc.) build up to unacceptable levels.
[0060] The following example, produced by computer model, illustrates typical parameters of a gasification reactor process for halogenated materials.
EXAMPLE 1
[0061] The following feeds streams are fed to a gasifier through an appropriate mixing nozzle:
Chlorinated Organic Material 9037 kg/hr Oxygen (99.5% v purity): 4419 kg/hr Recycle Vapor or moderator: 4540 kg/hr [58.8 wt % water vapor, 41.2 wt % hydrogen chloride]
[0062] The resulting gasification reactions result in a synthesis gas stream rich in hydrogen chloride.
[0063] In a preferred embodiment of the present invention, referencing the above example, this stream would be cooled or quenched and passed through an absorption step where the hydrogen chloride is recovered in an aqueous solution. This aqueous solution would be forwarded to a distillation system whose principal purpose is to distill nearly water free hydrogen chloride as an overhead product. The distillation tower is preferably operated at a pressure sufficient to flow side-draw vapor through a superheater, through a control valve, and through a gasifier mixing nozzle. A vapor side-draw is preferably extracted from a “reboiler section” of a distillation tower at a flowrate to complete the plant water balance. For the above example this would be per the flowrate and composition described for a gasifier feed. The vapor is preferably passed through a superheating exchanger imparting typically 10-20° C. superheat to the vapor, to insure that no liquid droplets remain. This vapor would then be fed to a gasifier mixing nozzle as a moderator stream.
[0064] Alternatively and/or in addition to the above system, a synthesis gas which has been absorbed free of bulk hydrogen chloride, as described above and illustrated as stream 418 in FIG. 4, passes through a finishing system 700 , FIG. 1B, where essentially all hydrogen chloride and other contaminants are recovered. This clean synthesis gas can then be fed to a commercially available carbon dioxide removal system, illustrated as unit 700 ′ in FIG. 1B. Carbon dioxide can be absorbed, as is known, from the syngas, liberated from any solvent or sorbent, compressed if necessary, and fed back to a gasifier feed nozzle as stream 730 in FIG. 1B, also as a moderator.
[0065] [0065]FIG. 1B, discussed initially, illustrates in block flow diagram form the addition of a carbon dioxide recovery unit 700 ′ after syngas finishing unit 700 . Tables 2 A, 2 B and 2 C illustrate a mathematical model run of a prior art carbon dioxide recovery unit and illustrate that it is known to recover CO 2 from syngas streams. FIG. 1B also illustrates a CO 2 recycle stream 730 recycled back and fed to a gasifier 200 . The CO 2 would preferably be fed through a nozzle or burner in a passageway provided for an inert gas moderator, such as steam.
[0066] Tables 1A and 1B illustrate the mole fractions of exit gas from the secondary reactor of FIG. 2 in a model run upon varying the moderator flow rate. The tables chart the breakdown of stream 210 when using a hydrogen halide/steam recycle moderator. The flow rate in lbs/hr of the moderator stream was varied from 2,000 lbs/hr to 20,000 lbs/hr. Results by mathematical model were computed with and without a nitrogen purge. Note the increased oxygen content as evidenced by decreasing CO 2 and H 2 O concentrations as recycled vapor moderator flow is increased. The higher concentrations support the formation of soot. Another key factor to note for the operation is the decreasing fraction of HCN and MCBZ, for the various moderator flows, indicating more complete destruction of undesirable species as the moderator flow increased.
[0067] Tables 3A-3E illustrate, from a mathematical model, the composition of various streams indicated in FIG. 2—FIG. 5 for a sample run. The heat and material balances demonstrate balancing of the water across the plant by recycling of the water.
[0068] The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials, as well as in the details of the illustrated system may be made without departing from the spirit of the invention. The invention is claimed using terminology that depends upon a historic presumption that recitation of a single element covers one or more, and recitation of two elements covers two or more, and the like.
Exit Gas From Secondary Reactor (Stream #210) using HCI/Steam recycle Moderator Basis: 6-30-99 RCI feed slate HCI/steam recycle from Desorber as moderator fluid O2/Fuel varied to control primary gasifier to 1450 C 1.5 MM Btu/hr heat loss from primary 1.5 MM Btu/hr heat loss from secondary 1000 #/hr N2 purge flow (except if noted) 75 psig operating pressure Aspen File Folder: \Gasifier with recycle HCI vapor\ 2,000 5,000 No 2 No N2 Moderator Flow (#/hr) 2,000 purge 3,000 5,000 purge 10,000 15,000 20,000 Substream: MIXED Mole Frac WATER 9.43E-06 3.51E−06 1.07E−02 4.54E−02 4.36E−02 1.24E−01 0.190369 0.246732 N2 0.022592 0.000138 0.027186 0.025582 0.001352 0.0223 0.019777 0.017778 O2 0.00E+00 9.39E−21 5.87E−14 1.25E−12 1.03E−12 1.38E−11 4.60E−11 1.06E−10 CO2 6.76E−06 2.41E−06 7.10E−03 2.72E−02 2.60E−02 6.13E−02 0.081936 0.095095 CO 0.496939 0.50605 0.479269 0.429943 0.442537 0.336036 0.2695 0.219925 H2 0.211813 0.219081 0.220143 0.216676 0.224961 0.201889 0.184427 0.166906 HCL 0.249677 0.259451 0.249226 0.249262 0.25546 0.249337 0.2494 0.249446 CL2 6.83E−08 8.51E−08 6.74E−08 7.22E−08 7.20E−08 8.53E−08 9.95E−08 1.15E−07 CL 1.54E−05 1.94E−05 1.56E−05 1.68E−05 1.66E−05 1.94E−05 2.18E−05 2.42E−05 CH4 6.59E−03 6.98E−03 6.30E−03 5.92E−03 6.07E−03 5.15E−03 0.0045531 0.004081 HCN 0.011664 2.60E−03 1.15E−05 2.30E−06 6.00E−07 5.51E−07 2.36E−07 1.21E−07 NH3 3.72E−06 2.90E−07 4.29E−06 4.00E−06 9.76E−07 3.26E−06 2.63E−06 2.12E−06 FORMHYDE 4.77E−07 4.97E−07 4.77E−07 4.20E−07 4.49E−07 3.04E−07 2.22E−07 1.64E−07 NAPTHALN 1.30E−08 1.37E−08 1.24E−08 1.16E−08 1.19E−08 1.01E−08 8.95E−09 8.03E−09 C2HCL5 2.12E−22 2.08E−21 1.53E−28 7.04E−30 0.00E+00 6.03E−31 1.69E−31 6.85E−32 C2H2CL4U 3.43E−18 3.01E−17 2.54E−24 1.11E−25 0.002+00 8.39E−27 0.00E+00 0.00E+00 PERCHLOR 3.65E−16 3.52E−15 2.65E−22 1.23E−23 0.00E+00 1.06E−24 3.01E−25 1.23E−25 CCL4 1.41E−16 5.04E−16 1.17E−19 2.63E−20 0.00E+01 8.77E−21 5.30E−21 3.83E−21 C2H2CL4S 8.06E−18 7.07E−17 5.96E−24 2.61E−25 3.44E−25 1.97E−26 0.00E+00 0.00E+00 TCE 5.20E−12 4.58E−11 3.87E−18 1.72E−19 0.00E+00 1.33E−20 0.00E+00 0.00E+00 C2H3CL3 5.16E−14 4.11E−13 3.91E−20 1.64E−21 0.00E+00 1.10E−22 0.00E+00 0.00E+00 C2CL6 1.17E−26 1.27E−25 8.25E−33 0.00E+00 0.00E+00 0.00E+00 1.23E−35 5.65E−35 PDC 4.48E−13 8.20E−12 3.12E−22 2.46E−24 3.94E−24 3.36E−26 0.00E+00 0.00E+00 EPI 9.57E−19 7.38E−18 7.54E−25 2.71E−26 3.86E−26 1.20E−27 0.00E+00 0.00E+00 DCIPE 5.12E−30 6.03E−28 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 0 2M2P 1.65E−16 1.88E−14 9.24E−32 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 123TCP 3.20E−16 6.33E−15 2.17E−25 1.78E−27 0.00E+00 2.70E−29 0.00E+00 0.00E+00 PROPANAL 1.31E−11 8.57E−11 1.04E−17 3.53E−19 0.00E+00 1.34E−20 0.00E+00 0.00E+00 ACETONE 1.77E−11 1.11E−10 1.41E−17 4.70E−19 0.00E+00 1.74E−20 0.00E+00 0.00E+00 BENZENE 2.13E−08 2.25E−08 2.03E−08 1.91E−08 1.91E−08 1.66E−08 1.47E−08 1.32E−08 33DCPENE 1.73E−11 3.48E−10 1.18E−20 9.87E−23 1.51E−22 1.55E−24 0.00E+00 0.00E+00 13DCPENE 9.42E−11 1.87E−09 6.43E−20 5.34E−22 0.00E+00 8.32E−24 0.00E+00 0.00E+00 HXCLBZ 9.29E−23 4.33E−20 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 0 NCL3 0 7.62E−27 6.08E−26 7.07E−26 1.59E−26 9.71E−26 1.26E−25 1.59E−25 3CLACN 1.65E−13 3.10E−13 1.16E−22 1.05E−24 0.00E+00 2.06E−26 0.00E+00 0.00E+00 1-3BCH 3.76E−21 6.31E−20 2.67E−30 1.76E−32 0.00E+00 0.00E+00 0.00E+00 0 1-2BCH 1.51E−20 2.55E−19 1.08E−29 7.10E−32 0.00E+00 0.00E+00 0.00E+00 0 2-3DCBUT 9.16E−16 4.18E−14 5.70E−28 8.79E−31 1.65E−30 0.00E+00 0.00E+00 0 C4CL6 8.80E−30 6.65E−28 0.00E−00 0.00E+00 0.00E+00 0.00E+00 0 0 SIO2 0 0 0 0 0 0 0 0 SOOT 0 0 0 0 0 0 0 0 BO 1.13E−18 2.02E−17 8.20E−28 5.57E−30 0.00E+00 5.06E−32 0.00E+00 0.00E+00 BGLYCOL 7.88E−26 4.80E−25 6.40E−32 1.79E−33 0.00E+00 0.00E+00 0.00E+00 0 BUTANAL 8.23E−15 1.35E−13 5.88E−24 3.88E−26 6.63E−26 3.37E−28 0.00E+00 0.00E+00 IPROPCL 7.01E−11 1.18E−09 5.02E−20 3.81E−22 0.00E+00 4.63E−24 0.00E+00 0.00E+00 PROPCL 9.59E−11 1.63E−09 6.88E−20 5.24E−22 8.54E−22 6.41E−24 4.56E−25 5.62E−26
[0069] [0069] 2,000 5,000 No N2 No N2 Moderator Flow (#/hr) 2,000 purge 3,000 5,000 purge 10,000 15,000 20,000 Substream: MIXED Mole Frac 2CLPENE 3.95E−08 7.24E−07 2.78E−17 2.22E−19 0.00E+00 3.08E−21 0.00E+00 0.00E+00 PHENPROP 9.45E−19 1.67E−15 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 0 MPK 1.18E−11 8.41E−09 4.79E−33 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 PHENOL 5.82E−10 6.36E−08 3.03E−25 8.48E−29 0.00E+00 5.19E−32 0.00E+00 0.00E+00 AMS 1.25E−08 6.07E−05 4.13E−35 0.00E+00 0.00E+00 0.00E+00 0 0 ODCB 1.12E−08 3.72E−06 5.00E−27 3.43E−31 0.00E+00 0.00E+00 0.00E+00 0.00E+00 PARADOW 1.02E−08 3.35E−06 4.52E−27 3.10E−31 0.00E+00 0.00E+00 0.00E+00 0.00E+00 MCBZ 1.60E−05 4.89E−03 7.33E−24 4.84E−28 0.00E+00 0.00E+00 0.00E+00 0.00E+00 PYRENE 8.21E−09 8.70E−09 7.85E−09 7.38E−09 7.56E−09 6.42E−09 5.67E−09 5.09E−09 133TCPEN 3.64E−14 7.80E−13 2.41E−23 2.08E−25 0.00E+00 3.61E−27 0.00E+00 0.00E+00 ALLYL-CL 4.41E−08 1.24E−07 3.11E−17 2.50E−19 3.88E−19 3.51E−21 0.00E+00 0.00E+00 CBE 0 0 0 0 0 0 0 0 PHENBUTE 8.33E−12 1.01E−07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 0 DPHENMP 0.00E+00 7.46E−15 0.00E+00 0.00E+00 0.00E+00 000E+001 0 0 HBR 0 0 0 0 0 0 0 0 BR2 0 0 0 0 0 0 0 0 SICL4 6.53E−04 6.91E−04 2.33E−07 1.34E−09 1.58E−08 1.88E−09 8.25E−10 5.03E−10 FE2O3 0 0 0 0 0 0 0 0 FECL3 5.06E−06 5.36E−06 4.84E−06 4.55E−06 4.66E−06 3.96E−06 3.50E−06 3.14E−06 AL2O3 0 0 0 0 0 0 0 ALCL3 7.93E−06 8.40E−06 7.58E−06 7.13E−06 7.30E−06 6.20E−06 3.70E−06 2.60E−06 CAO 0 0 0 0 0 0 0 0 CACL2 7.21E−06 7.63E−06 6.89E−06 6.48E−06 6.64E−06 6.63E−06 4.98E−06 4.46E−06 BR 0 0 0 0 0 0 0 0 23DCPENE 1.99E−10 3.92E−09 1.36E−19 1.12E−21 0.00E+00 1.74E−23 0.00E+00 0.00E+00 22DCP 6.83E−14 1.24E−12 4.75E−23 3.74E−25 6.00E−25 5.08E−27 0.00E+00 0.00E+00 C5CL5N 4.79E−24 6.55E−23 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 0 C5H2CL3N 6.57E−16 7.58E−15 3.57E−31 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0 C5HCL4N 2.94E−20 3.71E−19 1.55E−35 0.00E+00 0.00E+00 0.00E+00 0 0 DICLCNPY 3.25E−15 7.59E−15 1.72E−33 0.00E+00 0.00E+00 0.00E+00 0 0 BISETHER 0 0 0 0 0 0 0 0 ACROLEIN 1.27E−08 8.94E−08 9.94E−15 3.52E−16 0.00E+00 1.52E−17 0.00E+00; 0.00E+00 CL2PNOL 4.86E−20 3.50E−19 3.76E−26 1.31E−27 1.93E−27 5.49E−29 0.00E+00 0.00E+00 CH2CL2 2.72E−08 7.96E−08 2.37E−11 4.89E−12 5.73E−12 1.28E−12 6.00E−13 3.38E−13 Total Flow lb mol/hr 1321.261 1247.963 1381.906 1470.352 1434.68 1691.44 1912.531 2133.624 Total Flow lb/hr 32529.66 31126.74 33617.81 35871.65 34762.16 41528.93 47199.24 52887.04 Total Flow gal/min 58921.15 56368.69 61749.02 65956.6 64290.43 76400.18 86786.61 97143.3 Temperature C. 1376.724 1397.981 1380.072 1386.49 1384.792 1397.981 1405.718 1411.342 Pressure psig 74.5 74.5 74.5 74.5 74.5 74.5 74.5 74.5 Vapor Frac 1 1 1 1 1 1 1 1 Liquid Frac 0 0 0 0 0 0 0 0 Solid Frac 0 0 0 0 0 0 0 0 Enthalpy Btu/lb mol −14478.5 −14979.1 −16364 −20516.2 −21031.3 −29004.8 −35508.6 −40677.4 Enthalpy Btu/lb −588.075 −600.556 −672.665 −840.944 −867.99 −1181.34 −1438.82 −1641.05 Enthalpy Btu/hr −1.91E+07 −1.87E+07 −2.26E+07 −3.02E+07 −3.02E+07 −4.91E+07 −6.8E+07 −8.7E+07 Entropy Btu/lb mol-R 22.80366 22.93713 22.34239 21.53223 21.63093 19.6209 18.02903 16.70795 Entropy Btu/lb-R 0.926219 0.919617 0.918414 0.88259 0.892736 0.799144 0.730543 0.67405 Density lb mol/cu ft 2.80E−03 2.76E−03 2.79E−03 2.78E−03 2.78E−03 2.76E−03 0.002747 0.002738 Density lb/cu ft 0.068832 0.068846 0.067877 0.067807 0.061413 0.06777 0.067805 0.067876 Average MW 24.62016 24.94203 24.32713 24.39665 24.22991 24.55241 24.67894 24.78743
[0070] [0070] GLOBAL GAS/SPEC TECHNOLOGY GROUP AMINE PLANT PROGRAM DATE: 16 DEC. 1999 SALES: STC NUMBER: 99438UU RUN BY: DUPART COMPANY: DOW PLANT NAME: SYN GAS PLANT LOCATION: MIDLAND RESULTS GIVEN TO: HENLEY SOLVENT TYPE: MEA TREATED GAS REQUESTED. 95+% PURITY HYDROGEN INLET GAS 12.800 MMSCFD,(DRY) 0.000% H2S 100 Deg F. 38.013% CO2 74.7 Psia 0.000% CH4 0.000% C2H6 0.000% C3H8 0.000% i-C4H10 0.000% n-C4H10 0.000% i-C5H12 0.000% n-C5H12 0.000% C6H14 0.000% C7H16+ 0.000% Ar 0.000% CO 0.000% N2 60.723% H2 1.264% H2O RUN CONDITIONS TREATED GAS H2S CONCENTRATION, WET BASIS 0.00 PPMV TREATED GAS CO2 CONCENTRATION, WET BASIS 0.1476 VOL % BAROMETRIC PRESSURE 14.70 Psia ABSORBER BOTTOM PRESSURE 74.70 Psia ABSORBER LEAN AMINE FEED TEMPERATURE 110 F. ABSORBER OVERHEAD TEMPERATURE 218 F. ABSORBER BOTTOMS TEMPERATURE 136 F. STRIPPER BOTTOMS PRESSURE 12.00 Psig STRIPPER REFLUX RATIO 2.00 Mol/Mol STRIPPER OVERHEAD TEMPERATURE 218 F. STRIPPER FEED TEMPERATURE 205 F. STRIPPER BOTTOMS TEMPERATURE 246 F. ACID GAS TEMPERATURE EXITING CONDENSER 120 F. LEAN COOLER INLET TEMPERATURE 176 F. COOLING WATER INLET/OUTLET 90 F. 110 F. AIR COOLING INLET/OUTLET 90 F. 110 F.
[0071] [0071] GLOBAL GAS/SPEC TECHNOLOGY GROUP PLANT PROGRAM AMINE VARIABLES CO2 LEAN SOLVENT LOADING 0.100 Mol/Mol CO2 NET SOLVENT LOADING 0.251 Mol/Mol CO2 GROSS SOLVENT LOADING 0.351 Mol/Mol H2S LEAN SOLVENT LOADING 0.000 Mol/Mol H2S NET SOLVENT LOADING 0.000 Mol/Mol H2S GROSS SOLVENT LOADING 0.000 Mol/Mol SOLVENT CONCENTRATION 15 wt % SOLVENT CIRCULATION RATE 1750.0 USGPM GAS FLOW/PERFORMANCE DATA INLET CO2 PARTIAL PRESSURE 1487.29 mmHg INLET H2S PARTIAL PRESSURE 0.00 mmHg NET CO2 REMOVAL 539.91 lbmole/hr NET H2S REMOVAL 0.00 lbmole/hr PERCENT CO2 REMOVED/SLIPPED 99.76 / 0.24 ENERGY BALANCE REBOILER DUTY 77.684 MMBTU/hr STRIPPER CONDENSER DUTY 22.069 MMBTU/hr CROSS EXCHANGER DUTY 60.428 MMBTU/hr LEAN SOLVENT COOLER DUTY 56.351 MMBTU/hr UNIT REBOILER DUTY 143884 BTU/lbmole A G. ESTIMATED EQUIPMENT SIZES ABSORBER DIAMETER (ESTIMATE FOR TRAYED) 7.6 ft ABSORBER TRAY SPACING/No. OF TRAYS 24 in / 20 ABSORBER DIAMETER: 1.5 IN. METAL PALL RINGS 5.6 ft CARBON: (% Slip/Vol. (ft{circumflex over ( )}3)/Dia. (ft)) 10 / 467.88 / 7.46 STRIPPER DIAMETER (ESTIMATE FOR TRAYED) 13.0 ft STRIPPER TRAY SPACING/No. OF TRAYS 24 in / 20 STRIPPER DIAMETER: 1.5 IN. METAL PALL RINGS 9.5 ft HEAT EXCHANGE EQUIPMENT: AREA (ft{circumflex over ( )}2) LMTD (F) Uo (BTU/hr*ft{circumflex over ( )}2*F) CROSS EXCHANGER 12434 40.5 120 REBOILER 9996 51.8 150 LEAN COOLER (WATER) 11278 38.4 130 LEAN COOLER (AIR) 13329 38.4 110 REFLUX CONDENSER (WATER) 3297 60.8 110 REFLUX CONDENSER (AIR) 4836 60.8 75 LEAN COOLER H2O (USGM) 5640.7 LEAN COOLER FAN (hp) 435.0 REFL. COND. H2O (USGPM) 2204.6 REFL. COND. FAN (hp) 170.3
[0072] [0072] GLOBAL GAS/SPEC TECHNOLOGY GROUP AMINE PLANT PROGRAM PUMPING EQUIPMENT ESTIMATES AMINE CHARGE PUMP (P.D.) 68.07 hp AMINE CHARGE PUMP (CENTR.) 102.10 hp AMINE BOOSTER PUMP 105.00 hp REFLUX WATER PUMP 2.26 hp STREAM CONDITIONS INLET SALES ACID GAS STREAMS (lbmole/hr) GAS GAS GAS TEMPERATURE, Deg F. 100 110 120 PRESSURE, Psia 74.70 72.70 22.70 Ar 0.00 0.00 0.00 H2 864.52 862.92 1.60 N2 0.00 0.00 0.00 CO 0.00 0.00 0.00 CH4 0.00 0.00 0.00 C2H6 0.00 0.00 0.00 C3H8 0.00 0.00 0.00 C4H10+ 0.00 0.00 0.00 CO2 541.21 1.30 539.91 H2S 0.00 0.0000 0.00 H2O 18.00 15.41 43.34 TOTAL (lbmole/hr) 1423.72 879.64 564.84 TOTAL (M lb/hr) 25.89 2.07 24.55 DENSITY (lb/ft{circumflex over ( )}3) 0.222 0.029 0.154 ACTUAL ft{circumflex over ( )}3/min 1942.10 1210.90 2664.27 LEAN RICH SOLVENT STREAMS (lbmol/hr) AMINE AMINE TEMPERATURE, Deg F. 110 136 PRESSURE, Psia 72.7 74.7 Ar 0.00 0.00 H2 0.00 1.60 N2 0.00 0.00 CO 0.00 0.00 CH4 0.00 0.00 C2H6 0.00 0.00 C3H8 0.00 0.00 C4H10+ 0.00 0.00 CO2 214.71 754.62 H2S 0.00 0.00 H2O 41254.34 41256.92 MEA 2147.09 2147.09 TOTAL (lbmole/hr) 43616.14 44160.23 TOTAL (M lb/hr) 883.80 907.63 DENSITY (lb/ft{circumflex over ( )}3) 62.96 64.20 USGPM 1750.00 1762.54 USGPM MAKE-UP RE FLUX H2O FLOW 1.47 37.72
[0073] [0073] Stream Number: 144 200 210 280 281 282 285 290 291 293 295 296 299 530 733 To: R-3200 R-3210 P-3280 R-4 E-3280 D-3280 E-3200 R-3200 R-3200 R-3200 R-3206 E-3280 R-3200 R-3200 From E-31-10 R-3200 D-3280 P-3280 Q3200 E-3280 E-3280 LIQUID VAPOR VAPOR LIQUID LIQUID LIQUID LIQUID VAPOR VAPOR LIQUID VAPOR VAPOR LIQUID VAPOR VAPOR Substream: MIXED Mole Frac WATER 0 0.1706242 0.1683706 0 0 0 0 0 0 1 0 0 0 0.743 0.01 N2 3.29E−04 1.17E−03 1.17E−03 0 0 0 0 5.00E−03 5.00E−03 0 1 0 0 0 3.00E−03 O2 0 7.05E−11 2.25E−11 0 0 0 0 0.995 0.995 0 0 0 0 0 0 CO2 0 0.0700694 0.0723234 0 0 0 0 0 0 0 0 0 0 0 0.116 CO 0 0.3104558 0.3082029 0 0 0 0 3 0 0 0 0 0 0 0.34 H2 0 0.2112548 0.2139049 0 0 0 0 0 0 0 0 0 0 0 0.33 CL2 0 1.05E−07 5.86E−08 0 0 0 0 0 0 0 0 0 0 0.257 0 CL 0 2.86E−05 1.75E−05 0 0 0 0 3 0 0 0 0 0 0 0 CH4 0 1.35E−03 1.35E−03 0 0 0 0 3 0 0 0 1 0 0 1.00E−03 HCN 0 9.96E−08 9.25E−05 0 0 0 0 0 0 0 0 0 0 0 0 NH3 0 8.11E−07 8.13E−07 0 0 0 0 0 0 0 0 0 0 0 0 FORMHYDE 0 2.89E−07 2.95E−07 0 0 0 0 0 0 0 0 0 0 0 0 BENZENE 1.49E−03 1.53E−07 1.53E−07 0 0 0 0 0 0 0 0 0 0 0 0 SOOT 0 4.50E−03 4.50E−03 0 0 0 0 0 0 0 0 0 0 0 0 FECL3 4.00E−05 3.59E−06 3.9E−06 0 0 0 0 0 0 0 0 0 0 0 0 DOWTH-RP 4.00E−05 3.59E−06 3.89E−06 0 0 0 0 0 0 0 0 0 0 0 0 Mass Flow LB/HR 0 0 0 1 1 1 1 0 0 0 0 0 1 0 0 WATER 0 5115.789 5048.189 0 0 0 0 0 0 1.00E−03 0 0 0 5802.188 1201.463 N2 1.250002 54.3275 54.32505 0 0 0 0 41.92633 41.02633 0 1.00E−03 0 0 0 7937.243 O2 0 3.75E−06 1.20E−06 0 0 0 0 9530.3 9530.3 0 0 0 0 0 0 CO2 0 5132.189 5297.33 0 0 0 0 0 0 0 0 0 0 0 462.1573 CO 0 14472.71 14367.61 0 0 0 0 0 0 0 0 0 0 0 1428.547 H2 0 709.7647 716.3099 0 0 0 0 0 0 0 0 0 0 0 62.82928 HCL 0 13989.56 13990.23 0 0 0 0 0 0 0 0 0 0 4137.012 0 CL2 0 13989.56 13990.23 0 0 0 0 0 0 0 0 0 0 4107.012 0 CL 0 1.085736 1.033508 0 0 0 0 0 0 0 0 0 0 0 0 CH4 0 33.10844 36.10644 0 0 0 0 0 0 0 0 1.00E−00 0 0 1.51507 HCN 0 4.03E−03 4.16E−03 0 0 0 0 0 0 0 0 0 0 0 0 NH3 0 0.0201496 0.0230315 0 0 0 0 0 0 0 0 0 0 0 0 FORMHYDE 0 0.0144203 0.0147523 0 0 0 0 0 0 0 0 0 0 0 0 NAPTHALN 0 0.0158562 0.0158562 0 0 0 0 0 0 0 0 0 0 0 0 BENZENE 16.37100 0.0190582 0.0190582 0 0 0 0 0 0 0 0 0 0 0 0 SOOT 0 90.03299 90.03299 0 0 0 0 0 0 0 0 0 0 0 0 FECL3 1.050234 1.050234 1.050234 0 0 0 0 0 0 0 0 0 0 0 0 DOWTH-RP 0 0 0 5.00E+05 5.00E+05 5.00E+05 5.00E+05 0 0 0 0 0 5 0 0 ACI Components 2003.8033 Total flow LB/ 140.6467 1664.297 1664.289 2115.487 2115.767 2115.446 2115.467 299.3297 299.3297 5.55E−05 3.57E−05 6.25E−08 0.0211544 439.4496 94.44552 MOL/HOUR Total Flow LB/HR 18005.1 39802.32 39802.32 5.00E+05 5.00E+05 5.00E+05 5.00E+05 9572.227 9572.227 1.00E−03 1.00E−03 1.00E−06 5 10000 2000 Total Flow GAL/ 35.60107 77079.35 75149.24 1108.471 1108.515 1114.251 1108.471 1897/831 2793.588 2.31E−06 2.27E−04 2.19E−07 9.75E−03 4667.781 334.4008 MIN Temperature C. 150 1450 1397.446 134.7998 200.0458 205.9968 200 30 150 204.4441 30 30 30 200 195 Pressure PSIG 239 75 74.5 15 50 135 15 100 95 235 100 160.3569 85.30405 90 300 Vapor frac 0 1 1 0 0 0 0 1 1 0 1 1 0 1 1 Enthalpy BTU/HR 0.09E+06 5.12E+07 5.27E+07 6.71E+07 6.71E+07 7.01E+07 6.71E+07 11335.69 4.88E−05 −0.513492 1.54E−03 −2.01E−03 −9.871647 −3.74E+07 −4.18E+00 Density LB/CU FT 63.05406 0.0640565 0.0657017 56.23808 56.23505 55.04578 56.23807 0.6208323 0.4287346 53.90761 0.5485749 3.5086655 63.90579 0.2670977 0.7456641 Average Mwe 128.0186 23.79522 23.79538 236.3569 236.3568 236.3568 236.3568 31.97887 31.97887 10.01526 28.01348 16.04276 236.3568 22.75574 21.17623
[0074] [0074] TABLE 3B Stream Number: 210 310 TO: 0. 0.3310 From: VA MIXED LIQUID LIQUID LIQUID LIQUID LIQUID LIQUID LIQUID VAPOR VAPOR LIQUID Mole Frac H2O CH4 CL2 0 0 0 CO2 CO 0 0 BENZENE H HCLO 0 0 0 0 0 HCL HLN N2 0 0 0 0 PY 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 CL 0 0 0 O 0 0 0 0 0 OH 0 0 0 0 0 0 0 0 HCO 0 0 0 0 0 0 NH2CO2 0 0 0 0 0 0 0 Flow HCO 0 0 0 0 CO2 CO CYAN 0 0 BENZENE H2 HCLO 0 0 0 0 0 HCL HCN N2 NAPH 0 0 0 0 0 0 0 0 0 0 0 0 0 PY 0 0 0 0 0 0 0 0 0 0 0 0 0 0 OH 0 0 0 CL 0 0 0 0 0 0 0 0 0 0 0 0 0 COO 0 0 0 0 HCO 0 0 0 H 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Total Flow Total Flow Total Flow Temperature Pressure PSI Vapor 0 0 0 0 0 0 0 0 1 0 0 E Density QUID PHAS
[0075] [0075] TABLE 3C
[0076] [0076] TABLE 3D
[0077] [0077] TABLE 3E
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Methods for improving a gasification process for halogenated materials and in particular for producing useful end products such as anhydrous or highly concentrated hydrogen halides and/or synthesis gas, the methods including recycling water/hydrogen halide vapors and/or carbon dioxide to a gasification reactor.
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BACKGROUND OF THE INVENTION
The invention relates to a hi-hat percussion instrument for generating sounds by causing cymbals to come together, with one cymbal being attached to a fixed tube and the other cymbal being mounted on a bar that moves up and down and is caused to move by means of an operating device.
During musical performances, in addition to various drums and kettledrums, use is made of convex cymbal plates or cymbals. Individual or several cymbals can be used as percussion instruments, and they are hit with sticks or other appropriate devices to generate a sound. The cymbals can be caused to strike each other, and in this case two cymbals, preferably of the same size, are used to come together at their rims. At the time of such strike, the cymbals, which are preferably made of metal, oscillate, and, as a result, an especially long sound is generated. So-called hi-hats belong to standard percussion equipment. The main components of such instruments are two cymbals, which are caused to come together under a pedal control when the sound is generated in such a manner as to touch each other at their rims. Generally, the upper cymbal is movable, and the lower cymbal is fixed. When the pedal is moved, a bar, which is mounted at the lower end of the pedal by means of a spring and has its upper end attached to the upper cymbal, moves down inside a tube. The upper cymbal strikes the oppositely mounted cymbal that is attached to the tube. This results in generation of a typically metallic long-sustained sound. During concerts, as well as during recording on a sound carrier in a studio, hi-hats are used as rhythmic instruments, which are generally operated in a timely fashion the percussion instruments with the foot control. The other foot is likewise used for a bass drum.
There is a problem that with a single operating device, normally a pedal, only single strikes of maximum two cymbals can be performed. The footwork of the drummer is normally limited to the operating of the bass drum with one foot and to the bringing together the two cymbals while generating one sound with the other foot. In the best case, the variation capabilities reside in the fact that cymbals of different size can be used to generate different sounds. During a concert, a plurality of such hi-hats can be played by several persons simultaneously in order to generate an intensive or saturated sound. Certain effects, e.g., two offset sounds cannot be realized with the state-of-the art instruments. It can be achieved by using modern techniques during a studio recording session by receiving the sound through a plurality of channels in order to obtain a reach or offset sound. However, this requires high technology and take time, and such results cannot be accomplished during a live concert.
SUMMARY OF THE INVENTION
The invention is based on the problem of providing an instrument that would allow for improving sound quality with various tuning capabilities.
This problem is solved by the fact that the cymbals are provided with at least one more cymbal that is movable up and down, which can be operated by the operating device with the movable cymbal or independently thereof and which can be caused to come together with, and to strike the fixed cymbal and/or the other cymbal.
Such hi-hat can be referred to as a triple hi-hat, in which at least three cymbals are available that can be caused to come together with the middle cymbal or with each other for striking each other. This gives an enormous variety of additional sounds, which could not be achieved with prior art hi-hats. This also assures an obvious improvement of the play capabilities, and the operating device, which is partly based on the known devices that assure the movement of the upper cymbal to the fixed cymbal, allows for tuning, which will be described below. Other solutions are also possible, and, among other things, a purely hand operated operating device can be used, with both movable cymbals being moved to the fixed cymbal. Such operating device certainly does not meet today's requirements, and pneumatic and mechanical operating devices could still be used as described below.
According to one preferred embodiment, one more cymbal that is provided under the fixed cymbal is mounted on an outer tube which is movable by the operating device and which is surrounded by a fixed tube. Now, with the help of the operating device, with the same operating direction, the upper cymbal is moved to the middle cymbal and, at the same time, the lower cymbal is moved to the middle cymbal and strikes it. The direction of movement of the upper cymbal movable bar will now be explained in detail.
In the most preferred embodiment of a mechanical operating device for the triple hi-hat described herein, in which the bar is pivotally connected to a known pedal acts which upon a cable tie connected to the outer tube, with the cable tie, which is guided by a deflection roller, being attached to the outer tube. As will be explained below, it is possible, with the operating device of this type, that the upper cymbal will move down to the middle cymbal and, at the same time, the lower cymbal will move up to the middle cymbal. With this operating device, it is possible to assure that all three cymbals will come together at the same time, or they can come together with a predetermined time shift, which is exactly needed for the drummer. It is important that he uses one and the same pedal movement both for moving the bar down and, at the same time, to move the outer tube up through the cable tie and the deflection roller. Only one pedal is required for operating both movable cymbals, so the other foot can be used for operating other instruments, or it can rest.
The up and down moving bar and the cable tie that moves respectively can be moved by one and the same “foot” of the hi-hat, and the invention provides that the bar can be composite and can comprise a pedal part, a sleeve part, and a cymbal bar, with the pedal part being made as a tube supporting the deflection roller for the cable tie, and the attached sleeve part being made as an intermediate bar, which surrounds the deflection roller and connects to the cymbal bar. In this case, no through-going bar is used, and the mechanical system assures simultaneously the movement of the cable tie and its deflection over the deflection roller, whereby the downward movement of the bar can be transformed into the upward movement of the outer tube.
In order to assure the smooth upward movement of the additional cymbal on the one hand and to assure the uniform return to the initial position on the other hand, the foot of the outer tube that carries the additional cymbal is guided in a cylindrical tube that surrounds the fixed tube and has at the end an outer flange, which is positioned between two cylindrical springs located in the cylindrical tube. It is understood that both cylindrical springs should be supported on top and bottom in the cylindrical tube, and for that purpose, the cylindrical tube is provided with a cover on both ends. Both cylindrical springs are installed in such a manner as to assure the uniform up and down movement of the cymbal on the supporting outer tube.
The cable tie extends inside a hollow bar or pedal part. Its movement is respectively transmitted to the outer tube through the surrounding part. The invention provides that the cable tie, which is connected to the pedal, has its other end connected through a cam plate to the outer tube, the connecting cams being received in a groove of the fixed tube. This arrangement assures that the outer tube is reliably guided in its up and down movement and is prevented from rotating as the connecting cams are received in the groove and maintain the tube position during the up and down movement.
The distance from the additional cymbal to the fixed cymbal can be preferably varied by making the outer tube as a telescopic tube, which has an end piece on the cymbal to adjust the distance from the additional cymbal to the fixed cymbal and which has an appropriate clamp. The outer tube in this case is made of two parts in the upper area, i.e., in the zone of the end piece, the two parts being movable in each other and connectable by the clamp so that they are attached to the tube that controls the additional cymbal in order to move it.
The distance from the fixed cymbal can also be varied according to the invention by making the fixed pipe on the site of the cymbal infinitely telescopic. In this case an additional device such as a clamp is provided to assure the relative movement of both parts of the fixed tube in each other and to fix them to each other.
The pressure that is built by the cylindrical springs on the up and down moving outer tube can also be changed according to the invention, by the fact that the cylindrical tube that receives the cylindrical springs is connected to a retainer through a threaded joint to preload the springs. Depending on the amount at which the cylindrical tube is run on the threads of the retainer, the pressure increases, and the force needed to move the outer tube will also increase. In any case, it will be understood that the springs are sized in such a manner that they must only assure the return and the accurate guiding of the outer tube.
According to the invention, it is also provided that the movement of the additional cymbal can also be changed, e.g., in such a manner that it will move in the same direction with the upper cymbal. According to the invention, this is achieved by the fact that the pedal part of the bar is coupled directly to the outer tube through a cam drive plate. In this case, the reversal of movement of the pedal is neutralized because the bar and the outer tube are connected to each other, which also allows for the same movement direction. In this case, it is necessary that the cable tie be so elastic as not to be overloaded and broken.
More specifically, overload and breakage are prevented by the fact that the cable tie has a spring device that has its spring rate that is higher than that of the cylindrical springs. In this case, when the outer tube moves under pressure of the cylindrical springs, the spring device assures elongation of the cable tie, thus ruling out damage. The length and design of the spring device can meet certain requirements, and it is only necessary that the desired flexibility be imparted by means of the spring device, which prevents the cable from being damaged.
In another embodiment of the present invention, the above-described mechanical device is made with a pneumatic arrangement described below, wherein the switching between the up and down movement of the bar relative to the outer tube is assured pneumatically. In this case, according to the invention, the bar is provided with a piston, and the fixed tube is made as a cylinder having a top cylinder space and a bottom cylinder space. When the movable bar is moved down by the pedal inside the fixed tube, the outer tube with the lower cymbal that is attached to it must move up to move it to the fixed cymbal, and it is necessary to switch, which is done by the fact that, first, the piston that is movable in the cylinder moves down when the pedal is operated to form a pressure cushion. This pressure cushion is displaced into a so-called air chamber through outlets. The air cushion can only go this way when it is under the bottom of the cylinder. The resulting pressure increases with an increase in speed, whereby the outer tube with the lower cymbal that is attached to it moves up until the lower cymbal strikes the fixed cymbal. Instead of the above-described air cushion, a liquid can be used.
It is advantageous that the cylinder space that is located under the piston be sealed off with respect to the atmosphere and communicate through an outlet with a lower air chamber, which is provided between the outer wall of the fixed tube and the movable outer tube, and its outlet assures a connection to the lower air chamber. It is understood that the movement of the air cushions in the adjacent chambers is only possible if they have sufficient sealing with respect to the other chambers and to the outside air. This is only possible when the air moves along the predetermined path for the desired effect, first for the upward movement and then for the downward movement of the outer tube. Eventual connections to the outside air rule this out because the air will move through such holes along the path of the lowest resistance.
When the outer tube operated by operating the pedal moves up, a face is further provided, upon which the air cushion acts so that the outer tube moves up. This is due to the fact that the outer tube forms an air chamber defined by a ring piston. The ring piston is located on the inner wall of the outer tube and is positively connected thereto. The ring piston can be machined during fabrication of the outer tube, or it can be welded, threaded or by any other means connected later to the outer tube. It is used for assuring the movement of the outer tube as described above when the upper cymbal is caused to move down.
According to the invention, the upper cylinder space communicates with the atmosphere through the holes. When the piston moves down, the air flows to the upper cylinder space through the holes. If this is not the case, the piston can be moved down only under an enormous force. In the hi-hat according to the invention, this is exactly what is required in order to use the three-cymbal instrument as a two-cymbal instrument. When the pedal is released, the whole system should return to its initial position, and, more specifically, the piston should move further up. This is only possible if the openings are provided according to the invention between the cylinder spaces and the atmosphere, and the piston can displace the air that is present in the upper cylinder space to the outside practically without any resistance.
The air will also be displaced from the lower cylinder space into the lower air chamber, and the outer tube releases this pressure by retreating up. The air that is present in the upper air chamber cannot, however, escape, and it will be compressed, thus providing the desired spring effect.
This can be controlled because the ring piston divides the interior space between the fixed tube and the movable outer tube into a lower air chamber and an upper air chamber sealed off with respect to each other, and because a valve is provided in the outer wall of the upper air chamber, whereby the air cushion thus formed is maintained since the valve is designed and adjusted to open when a predetermined pressure is reached. When the pedal is released, the air that is present in the air chamber tends to expand and to exert pressure against the ring piston downwards, and the air in the lower air chamber is thus further displaced through the holes into the lower cylinder space. This allows the instrument to return to its initial position.
It is further provided that the lower cymbal and the outer tube, upon operation or release of the operating device, assure the downward movement of the outer tube to the initial position. The dead weight of the cymbals and of the outer tube works by itself or combined with the above-described air effect to return the system to the initial position. In any case, it is guaranteed that when the pedal is released, the movement back to the initial position is assured, and the pedal can be pressed again. This is especially important for high load when the instrument is used for a musical performance, and this is the mandatory requirement for such instruments.
As mentioned before, it is important that the upper and lower air chambers be isolated from each other in order for the air in the upper chamber to be compressed, whereas the pressure in the lower chamber is used to cause the ring piston and also the outer tube with the lower cymbal to move up. For this reason, an annular groove with an O-ring is provided in the outer wall of the fixed tube in the area of the ring piston. The combination of the annular groove and the O-ring assures the relative sealing of both chambers when the ring piston moves.
In another preferred embodiment, a valve for maintaining an air cushion in the air chamber is provided in the outer wall of the lower air chamber. The valve is designed and adjusted to open when a predetermined pressure is reached. By using this valve, the air cushion can be controlled in order to prolong or shorten the movement of the pedal back to the initial position. If an air cushion with high pressure is already present with high pressure in the chamber, the return travel of the pedal must be delayed in such a manner that outer tube will go so high that the lower cymbal strike the middle cymbal will be relatively short. On the contrary, is the air cushion is formed in such a manner that the air can be displaced from the cylinder space into the air chamber, then the travel will be respectively longer. In this case, the valve is adjusted in such a manner that the lower cymbal strikes the middle cymbal against the upper cymbal. The lower cymbal can strike the fixed cymbal simultaneously, before or after the middle cymbal. This allows the acoustic effect to become richer where the modern sound technology cannot be used. Such shifted strikes can be varied at will by the drummer. By adjusting the valve, the control can assure that the lower cymbal will not only strike shortly the middle cymbal, but it will also stay for a moment in this position. Both cymbals can then oscillate in a non-free oscillation mode, which will give a modified muffled sound. There is another advantageous adjustment capability. If the valve is opened, the air that escapes from the cylinder space, and, instead of pushing the outer tube up, this air flows outside through the open valve. The lower cymbal does not work. In this case, the triple hi-hat works like a conventional instrument.
Further, it would be advantageous to use a crossover valve. This valve reacts in both directions, inwardly and outwardly, and it can be adjusted to meet different requirements.
In order to achieve optimum oscillations of the cymbals, and more specifically, of the middle cymbal, which is struck by both the lower cymbal and the upper cymbal, the middle cymbal is undulated in the radial direction. With this configuration, the number, shape and size of the undulations can be a matter of choice, and it is guaranteed that the middle cymbal will not oscillate as a substantial mass even in the case when the strike occurs simultaneously, which is absolutely undesirable because the sound quality would be impaired. This effect is assured because of the pliable and less stiff structure of the cymbal, as well as because of its larger surface area. By changing the middle cymbal, the drummer can realize his “ideal” sound.
When the middle cymbal is shaped in this manner, it is preferred that, in order to assure the optimum strike thereon from above and below, the lower and upper cymbals be made convex and have an exaggerated curvature closer to the outer side, which gives the ideal oscillation conditions with a corresponding improvement of sound.
The hi-hat is subjected to a continuous and high load, which is why all joints of any individual component of the instrument are of great importance. More specifically, the bar is detachably connected to the upper cymbal. This force transmitting connection is assured by a preloaded joint, preferably or of metal or plastic, and in the preferred embodiment, the preloaded joint is adjustable in such a manner that with a looser preload, a good oscillation mode is assured with a reverberating sound, and with a tighter joint, “suppressed” oscillations obtain, with a muffled sound as a result. Moreover, the functioning of the cymbal can be altered or even stopped by loosening it on the bar.
The same result can be obtained if the outer tube in a preferred embodiment is detachably connected to the lower cymbal. This can give alterations to [illegible] in a simple manner.
For providing the above-described air cushions and movement of the outer tube, the bar has an annular groove with a seal under the piston in the area below the lower cylinder space and an annular groove with a seal above the upper cylinder space fore sealing with respect to the cylinder, and the piston is sealed with respect to the inner wall of the fixed tube also by means of an annular groove and a seal.
A similar sealing system is provided under the lower cylinder space in order to seal it off for the above-given reasons with respect to the outside air. With this system, when the piston starts moving down, the air does not escape from the chamber system, but is rather displaced from the lower cylinder space into the lower air chamber through the openings provided for this in the lower air chamber.
The same applies to the area above the upper cylinder space where the annular groove with the seal is provided for isolating the upper cylinder space.
In order to optimize the overflow between the lower cylinder space and the lower air chamber, it is preferred that a plurality of distributed outlets be provided in the periphery of the cylinder, leading to the lower air chamber. It is important that the air be displaced with a very high velocity from one chamber into the other. For this reason, the sections though which the path of the air extends should be as large as possible. In the ideal case, the fixed tube even in the area of the openings is made solid only at points where it is structurally required.
In order to reduce wear and to dispose of unnecessary joints, the bar and the piston are made integral.
The invention is distinguished by the fact that a musical instrument, a hi-hat, is provided which can have various uses and which allows for numerous sound variations for the music without using any additional devices. Moreover, the hi-hat has been transformed into a triple hi-hat, which not only allows an additional cymbal to be installed, but also, when it is necessary, only two cymbals can be used in a conventional manner. In this case, a corresponding joint that is used for mounting the additional lower cymbal is loosened, whereby only the upper cymbal can be moved toward the fixed cymbal to strike it. In practice, however, the three cymbals will be used according to the invention, of which one moves from top down and the other moves from bottom up to strike the middle cymbal. Although they are operated with a single pedal, the musician's capabilities are not restricted because he has appropriate adjustments available so as to alter and control the sound in such a manner as to generate a desired sound sequence. The above-described variety of capabilities will naturally interest an experimentally-inclined musician, and further effects will become available.
Other features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings, which show preferred embodiments with the necessary components and parts and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a triple hi-hat, a side elevation, with the support shaft in section.
FIG. 2 is the hi-hat of FIG. 1, a side elevation, shown with the pedal.
FIG. 3 shows the upper part of the hi-hat with three cymbals.
FIG. 4 shows the middle part of the support shaft with a joint between both parts of an outer tube and the fixed tube.
FIG. 5 is a longitudinal section through the lower part of the support shaft, showing a cylindrical tube for cylindrical springs.
FIG. 6 is a sectional view in FIG. 5, showing an embodiment of a support for the support shaft.
FIG. 7 is a side elevation of FIG. 6 .
FIG. 8 shows schematically the design of a pneumatic operating device.
FIG. 9 is an enlarged view of a detail, showing the “pneumatic” parts.
DETAILED DESCRIPTION
FIGS. 1 and 2 show a hi-hat 1 , which is also referred to as a triple hi-hat because, in addition to a known upper movable cymbal 2 and a fixed cymbal 3 , there is provided a lower cymbal 4 , which can be caused to move to the fixed cymbal 3 by means of an operating device 5 .
The fixed cymbal 3 is attached to the top end of a fixed tube 6 , and, although this is a conventional cymbal, it can be struck both from the bottom and from the top.
It can be seen in FIGS. 1, 2 and 3 that the cymbals 2 , 3 and 4 which are used have different diameters. More specifically, the lower cymbal is the largest cymbal 4 , which has the largest diameter.
The upper cymbal 2 is connected to a bar 7 , movable up and down, and the bar 7 is detachably connected to the upper cymbal 2 . An appropriate wing screw 48 can be seen.
With the help of the mechanical operating device 5 , which is explained with reference to FIGS. 1 through 7, the upper cymbal 2 is caused to move from the top to and to strike the fixed cymbal 3 , and the lower cymbal 4 can be moved from underneath towards the fixed cymbal 3 . It will be also shown below that it is also possible to cause both movable cymbals to move in the same direction.
A support shaft 49 for the cymbals 2 , 3 and 4 has different tubes extending in each other, and the innermost tube, i.e., a tubular bar 7 supports a cable tie 50 on a deflection roller 51 in such a manner that when a pedal 31 move down against the force of a spring 33 , an outer tube 14 , which is connected to the cable tie 50 , moves up. The bar 7 will at the same time move down in the conventional manner, whereby the upper cymbal 2 , which is connected to the bar, strikes the fixed cymbal 3 .
For supporting the cable tie 50 and the deflection roller 51 , the bar 7 is divided into a hollow pedal part 52 , a matching hollow sleeve part 53 , and a cymbal bar 54 , which are connected to each other. This system can be specifically seen in FIGS. 5, 6 and 7 . It can be seen in these figures that the cable tie 50 can move concentrically within the pedal part 52 , although the cable tie 50 is connected at the other end to a cam disk 63 , which connects the tie to the outer tube 14 . The cam disk 63 has connecting cams 64 which extend from the pedal part 52 and through the fixed tube 6 . The fixed tube has a groove 65 for this purpose.
The outer tube 14 has, in the zone of its foot 55 , a flange 58 , and this flange 58 is mounted between two cylindrical springs 59 and 60 . The cylindrical springs 59 , 60 are located in a cylindrical tube 57 , which is closed on top and bottom, so the cylindrical springs 59 , 60 can be supported. With this arrangement, the foot of the outer tube 14 is guided smoothly when the outer tube 14 moves either up or down. The cylindrical springs 59 , 60 serve in both directions to assure the necessary smooth guidance and also to assure the return of the flange 58 together with the outer tube 14 when the foot is removed from the pedal.
The cylindrical springs 59 , 60 can be preloaded in such a manner that the cylindrical tube 57 is locked by means of a threaded retainer 69 . The cylindrical tube 57 can be moved more or less by means of the retainer 69 , thus adjusting the preload of the cylindrical springs 59 , 60 as required.
As mentioned above, the upper cymbal is detachably connected by means of the wing screw 48 to the bar 7 , more specifically, to the cymbal rod 54 . Thus the wing screw 48 allows the distance from the upper cymbal 2 to the fixed cymbal 3 to be adjusted.
The distance from the lower cymbal 4 to the middle cymbal 3 , which is stationary, can be adjusted because an end piece 67 of the outer tube 14 is telescopically mounted. Both ends of the outer tube 14 are connected to each other by means of a clamp 68 , so the position or the height of the lower cymbal 4 can be adjusted.
Not only can the position of the upper cymbal 2 and the lower cymbal 4 be varied, but also the middle fixed cymbal can be adjusted as well. For that purpose, there is provided a telescopic clamp 75 , which ties together both parts of the fixed tubes 6 that can moved inside each other, so the inner fixed tube 6 can be extended from the other tube. This is shown in FIG. 4 .
It can also be seen in FIG. 4 that the deflection roller 51 is journalled on an axle 74 of the fixed pipe 6 . This assures the reliable guidance of the cable tie 50 when the cable tie moves against the force of the cylindrical spring 59 or 60 .
The specific construction of the cymbals 2 , 3 , 4 has been already described. More specifically, FIG. 3 shows the specific configuration that can be used for the embodiment of the hi-hat, although it does not have any particular bearing on the embodiments described here. Other configurations can be used, e.g., the one that is shown in FIG. 8 .
With the arrangement illustrated in FIGS. 5, 6 and 7 , the lower cymbal 4 is moved towards the fixed cymbal 3 , and the upper cymbal 2 moves down towards the fixed cymbal 3 . If the lower cymbal should move in the same direction as the upper cymbal 2 , it can be done by loosening the clamp 68 to move it closer to the fixed cymbal 3 and then connecting directly to the bar 7 , to which the cable tie 50 is attached, by means of a cam drive plate 71 and the extending portion of the outer tube 14 . With this arrangement, both the additional cymbal 4 and the upper cymbal 2 will move down when the pedal 31 moves down or is pressed. In order to avoid overloading of the cable tie 50 , there is provided a spring device 72 , with the spring rate of this device being considerably greater than that of the cylindrical springs 59 , 60 . With this arrangement, the spring device 72 will only protect the cable tie 50 against overload.
FIG. 8 also shows an assembly of the hi-hat 1 . This hi-hat 1 is operated by means of the operating device 5 , which is normally the pedal 31 .
FIG. 1 illustrates an assembly of a triple hi-hat. The instrument is operated by means of the operating device 5 , which normally is the pedal 31 . This operating device can be used to move together or separately the upper cymbal 2 down and the lower cymbal up. The pedal 3 is connected in a force transmitting relation to the bar 7 , which has at its lower end a return spring 33 . The return spring 33 is compressed when the pedal 31 is operated and is expanded when the pedal 31 is released. This assures the return of the bar 7 to its initial position, after which it can be caused to move again when the pedal is operated. The bar 7 is surrounded by the fixed tube 6 to which the fixed cymbal 3 is attached. When the pedal 31 is pressed, the upper movable cymbal 2 strikes the fixed middle cymbal 3 to give a desired sound effect. The cymbals 2 , 3 are shaped in such a manner that they will always strike each other at their outer rims and have curvature 25 , 25 ′ in order to assure the most optimum oscillations of the cymbals 2 , 3 .
In devices of the prior art, the second or lower cymbal was made convex similarly to the upper cymbal. This is not the case with the triple hi-hat disclosed herein because not only the upper cymbal 2 , but also the lower cymbal 4 strikes the middle cymbal 3 . In order for this new requirement, more specifically, the requirement to assure optimum oscillation conditions for the middle cymbal 3 in both directions, to be met, the middle cymbal 3 has an undulated shape. Other configurations can also be used, e.g., a planar slightly convex domed configuration or a conventional convex domed configuration of the cymbal. All three cymbals 2 , 3 , 4 have a central hole. A circular surface is formed in the holes and is configured so that a fastener member 34 , 35 , 36 can be fitted. The fastener member 34 is used to assure the connection between the upper cymbal 2 and the bar 7 , the fastener member 35 is located between the middle cymbal 3 and the fixed tube 6 , and the fastener member 36 is located between the hollow tube 16 and the lower cymbal 4 . The fastener members 34 , 35 , 36 are made preferably of metal or plastic and, if possible, are mounted with a preload. With such fastening, the cymbals only in the central part, taking only the smallest possible area of the cymbals 2 , 3 , 4 , are preloaded, and the largest possible area of the cymbal bodies can oscillate freely.
In addition to the upper cymbal 2 , the operation of the pedal 31 also causes the lower cymbal 4 (if it is set up in this way) to move towards the middle cymbal 3 , which gives an additional sound. This sound can be additionally shifted with respect to the sound generated by the upper cymbal 2 .
The functioning of the lower cymbal 4 can be seen in FIG. 2 . When the pedal 31 is pressed, the bar 7 goes down with its piston 8 . The piston is surrounded by an upper cylinder space 10 and a lower cylinder space 23 , and the fixed tube 6 , which surrounds the piston 8 , defines a cylinder 13 . The fixed tube 6 closes the cylinder spaces 10 , 23 at top and bottom. In this specific embodiment, the piston 8 and the bar 7 are made integral which is important because of the high dynamic load on the instrument 1 .
In the embodiment shown in FIG. 2, the system is in the initial position. Upon the downward movement of the bar 7 , when the pedal 31 is pressed, the piston 8 , which is sealed by means of an annular groove 42 and an O-ring 43 , moves down. The air that is present in the lower cylinder space 23 is displaced by the piston 8 through outlets 9 into a lower air chamber 11 , which is defined between the outer wall 15 of the fixed tube 6 and the movable outer tube 14 . The outlets 9 are distributed over the periphery of the cylinder 13 and serve as overflow spaces, which should assure a good connection between the lower cylinder space 23 and the lower air chamber 11 .
In order for the lower cymbal 4 to be able to strike the middle cymbal 3 , the outer tube 14 , to which the lower cymbal 4 is attached, is movable. The air that is displaced from the lower cylinder space 23 causes the outer tube to move only down. The condition for this movement is a sufficiently large annular face 21 of a ring piston 20 upon which the air is acting. With this arrangement, the force can be reversed, and the downward movement of the bar 7 and piston 8 results in an upward movement of the outer tube 14 , with the consequence that the lower cymbal 4 strikes the middle cymbal 3 . In order to avoid underpressure, the inner wall of the upper cylinder space 10 has a hole 26 which establish communication with the atmosphere. During the downward movement of the piston 8 , outside air is drawn into the upper cylinder space 10 . The above-mentioned annular face 21 defines the lower face of the ring piston 20 , which is in a force transmission connection with the outer tube 14 . Also in this case, it is advisable that the outer tube 14 and the ring piston 20 be made integral because of the high dynamic load. The ring piston 20 can also be attached later by means of welding, threading, or other connecting joint to the outer tube 14 .
The air in the lower air chamber 11 is controlled by means of a valve 12 provided in the outer wall 18 of the lower air chamber 11 . To provide this valve 12 , a groove or an elongated hole is made in the outer tube 14 (not shown in the drawing). With this arrangement, the valve 12 remains in this position regardless of the outer tube 14 being in the position that is shown in the drawing or in a different position. This valve allows, for example, the amount of air admitted to the lower air chamber to be controlled to the extent that this air can cause the ring piston 20 and the outer tube 14 to move up. When the valve 12 is closed, a small quantity of air is sufficient to assure the coming together of the cymbals 3 , 4 and generation of a sound as a result of the upward movement of the outer tube 14 . In this case, the instrument 1 is set up in such a manner that the lower cymbal 4 will strike the middle cymbal 3 substantially earlier than the upper cymbal 2 does. If, on the other hand, the valve 12 is open, more air should be displaced from the lower cylinder space 23 into the lower air chamber 11 until the outer tube 14 starts moving. This adjustment also results in the fact that the lower cymbal will strike the middle cymbal 3 only after the upper cymbal 2 . Both sounds will then follow each other in a different order. It will be understood that if the valve 12 is so adjusted that the upper cymbal 2 and the lower cymbal 4 strike the middle cymbal 3 simultaneously, this will result in a substantially richer sound. It is further possible, by opening the valve 12 completely, to turn off the system of the instrument 1 that contains the lower cymbal 4 . In this case, the air that is displaced from the lower cylinder space 23 will find its natural way of the lowest resistance through the valve 12 instead of the path that would lead to the upward movement of the ring piston 20 .
A valve 37 in an outer wall 44 serves to control the upper air chamber 19 . First of all, this serves to control the spring effect that is generated by the air present in the air chamber 19 . If the valve 37 is completely shut off, this spring is hard to a certain extent. In this case, the outer tube 14 will go up fast when the pedal 31 is pressed and will then return under the spring effect. The air that is compressed during the upward movement of the outer tube tends to expand and push the outer tube 14 back to the initial position. The greater the opening of the valve 37 , the weaker this spring effect.
The upper air chamber 19 is located above the ring piston 20 . The upper and lower air chambers are sealed off with respect to each other by means of an annular groove 24 and an O-ring 22 . The air that is present in the upper air chamber 19 is compressed during the upward movement of the ring piston 20 until the spring effect occurs. The air tends to expand, and the ring piston 20 goes down even more together with the outer tube 14 . This results in the air that is present in the lower air chamber 11 being displaced through the holes back into the lower cylinder space 23 . This air presses, jointly with the force of the released return spring 33 , against the bar 7 . This initiates the upward movement of the piston 8 and also the return of the instrument 1 to the initial position. It should be noted that the lower cymbal 4 and the outer tube 14 are sized to have a dead weight with which the return of the lower cymbal 4 and the outer tube 14 to the initial position is assured when the pedal 31 is operated. The air compression is assured if the piston 8 has at least one O-ring seal.
By using various sealing means, a good sealing off of the system with respect to the ambient air must be achieved. In this embodiment, a system of annular grooves and O-rings is chosen. Thus, the lower sealing of the cylinder space 23 is assured by an annular groove 27 with an O-ring 28 , and the upper sealing of the upper cylinder space 10 is assured by an annular groove 38 with an O-ring 39 , with the upper air chamber 19 being sealed with an annular groove 40 and an O-ring 41 .
In the embodiment shown in FIGS. 8 and 9, the outer tube 14 is covered with a hollow tubular member 16 to protect against any potential damage. Another annular groove 29 with another O-ring 30 can be used if a single seal 42 , 43 cannot cope, e.g., when the piston 8 that is much longer is used. Reference numeral 32 shows the outer wall of the lower air chamber or the outer air chamber, which is filled though the outlets 9 when the pressure is lost.
The invention scope is defined by all the above-mentioned features taken in combination with the drawings.
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A hi-hat ( 1 ) is used as an instrument, especially as a percussion instrument. The inventive hi-hat consists of a set of in total three or more cymbals ( 2, 3, 4 ). An upper mobile cymbal ( 2 ) and a lower, also mobile cymbal ( 4 ) are struck against the middle, stationary cymbal ( 4 ) by means of a common operating device ( 5 ), in order to produce a noise. The movement of the pedal ( 31 ) is reversed by means of either an appropriate pneumatic arrangement with a piston ( 8 ) and corresponding cylinder chambers ( 10, 23 ) or a mechanical device which diverts the pedal movement via a cable ( 50 ) and a deflection pulley ( 51 ) so that the outer tube ( 14 ) moves upwards against the middle cymbal ( 3 ) whilst the rod ( 7 ) is pulled downwards in the opposite direction, hereby causing the upper cymbal ( 2 ) to strike the middle cymbal ( 3 ).
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BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to automotive vehicle body structure, and more particularly to the construction of automotive vehicle pillars to accommodate energy absorption.
2. Description of the Prior Art
In the design of modern automotive vehicles, it is has been a goal to provide body structures which manage the absorption of energy in response to the imposition of frontal loads. More recent design activity in the vehicle body arts has been directed to the management of energy imposed on the vehicle occupant compartment in response to loads imposed on the sides of the vehicle and to loading imposed within the vehicle occupant compartment. While the cushioning of surfaces facing the vehicle occupant compartment has long been practiced in the automotive industry, the basic, usually metal, structure of the body itself has been accommodated rather than made an integral part of the energy management design, although early designs, such as that exemplified in U.S. Pat. No. 5,163,730 to Welch, indicate the general principle of cushioning such structure is known. This cushioning, however, is disadvantageously limited to localized positions on the pillar, which may not provide optimal energy management in all applications.
More recently commonly assigned U.S. Ser. No. 08/225,689 disclosed a more comprehensive cushioning approach in certain pillar embodiments in which cushioning media are carried within the pillar. Accommodating such structure within a pillar is not, in all cases, possible or desirable.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome the disadvantages of the prior art and define an energy absorbing pillar structure which enhances the capability of the pillar to absorb energy in response to loads laterally imposed with respect to the vehicle.
This is accomplished through providing such a structure that includes an exterior panel, an interior panel, and an interior trim pillar secured to the interior panel configured to define a first energy absorbing chamber between the panels, the trim pillar including energy absorbing media carried within a second energy absorbing chamber therein defined.
BRIEF DESCRIPTION OF THE DRAWINGS
The efficacy of the invention pillar structure and its advantages over the prior art will become apparent to those skilled in the automotive body arts upon reading the following description with reference to the accompanying drawings, in which like numbers preceded by the figure number refer to like parts throughout the several views and in which:
FIG. 1 is a partial side view of an automotive vehicle;
FIG. 2 is a cross section taken along line 2--2 of FIG. 1;
FIG. 3 is a cross-sectional view similar to FIG. 2 illustrating an alternative embodiment;
FIG. 4 is a cross-sectional view similar to FIG. 3 illustrating another alternative embodiment; and
FIG. 5 is a cross-sectional view similar to FIG. 3 illustrating yet another alternative embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, in particular to FIG. 1 thereof, an automobile 10 is illustrated as having a body 12 having a lower portion such as indicated at the door 14, a roof portion 16, and pillars 18, 20. As is conventional, the pillars 18, 20 provide support for the roof 16 in closing the vehicle occupant compartment indicated generally at 22.
According to the present invention, the pillars 18, 20 are constructed to enhance energy absorption in response to loads imposed laterally of the pillars. As used herein, it is to be understood that the pillars 18, 20 extend generally vertically between the lower portion 14 of the vehicle 10 and the roof 16, and that loads imposed generally normal to this vertical extent are referred to as lateral or side loads.
The pillars 18, 20 are preferably fabricated as metal stampings. According to the present invention, they are configured to enhance energy absorption both by the shape and arrangement of the metal stampings and by cooperation with interior trim structure to define an overall energy absorbing pillar structure.
Turning now to FIG. 2, one preferred embodiment for the front or A-pillar 20 is illustrated as including an exterior panel 24, an interior panel 26, an interior trim pillar 28, and energy absorbing media 30 disposed within the trim pillar 28.
The exterior panel 24, which is illustrated in FIG. 2, defines an outwardly concave external surface 32. First and second peripheral flange portions 34, 36 bound an outwardly concave section 38 to define a truss-like structure adjacent the door 14. Known seal assemblies, generally denoted by the letter S are conventionally carried for sealing engagement between the panel 24 and the door 14; and the vehicle windshield W is mounted against the flange 34.
The interior panel 26 likewise includes first and second peripheral flanges portions 40, 42 positioned in facing relationship with respect to the flange portions 34, 36 of the exterior panel 24. A concave inward truss portion 44 having a profiled laterally inwardly facing surface 46 extends between the flange portions 40, 42.
The interior trim pillar 28 is carried interiorly of the interior panel 26 in complementary relationship with the surface 46 thereof. As shown in FIG. 2 the trim pillar 28 is of L-shaped cross section and includes external surfaces 48 abutting the facing surfaces 46 of the interior panel 26. The trim pillar 28 is illustrated as being fabricated from a relatively soft plastic or rubber material and is formed in a closed section to define an energy absorbing chamber 50 for containing the energy absorbing media 30. To cooperate in the response of the pillar 20 to the imposition of lateral loads it is necessary to fixedly secure the trim pillar 28 in the position shown. This may be accomplished by conventional fastening means such as acrylic foam tape, urethane adhesive, rivets, clips and other mechanical fasteners, illustration of which is not needed for those skilled in the automotive body arts.
With the panels 24, 26, and the trim pillar 28 so arranged, a first energy absorbing chamber 52 is defined between the exterior panel 24 and the interior panel 28, and a second energy absorbing chamber 50 is defined within the interior trim pillar 28.
According to this preferred embodiment, the energy absorbing medium 30 is preferably a viscous fluid, such as an oil or grease. Design thickness and configuration of the surrounding walls 54 defining the chamber 50 may established to either contain or release fluid in response to loading.
Turning next to FIG. 3, the configuration in this embodiment for the pillar 20 is essentially identical to that in FIG. 2 save the provision of an alternative energy absorbing medium 330, preferably defined as a generally C-shaped, outward opening, resilient spring assembly 74. Two springs 76, 78 are interleaved to be grounded against the inner panel 326. The spring 76 has an out-turned flange 80 that is secured to the flange 340 of interior panel 326, and the spring 78 has an out-turned flange 82 secured to the flange 342 of the interior panel 326.
Turning next to FIG. 4, the configuration in this embodiment for the pillar 20 is essentially identical to that in FIG. 2 save the provision of an alternative energy absorbing medium 430, preferably defined as a plurality of crushable tubes 84 extending generally parallel to the longitudinal axis of the pillar 20. It is contemplated that aluminum or rubber may be used in constructing the tubes, energy absorbing requirements of a particular vehicle application dictating the choice. In some applications it may be possible to eliminate the walls 454 of the trim pillar 430 and gang the tubes 84 together in complementary conformance with the surface 446 of the interior panel 426 in fixed relationship, as through the use of adhesives.
Turning lastly to FIG. 5, yet another energy absorbing medium is indicated at 530, differing from the medium 430 illustrated in FIG. 4 in that a spring member 86, preferably of metallic construction, is received in snap-in relationship at one end in a clip assembly 88 or other device adjacent the flange 542 of interior panel 526 and is adhesively secured at its other end, as indicated at 90, to the flange 540. This embodiment offers the capability of tailoring energy management response to loading in a variable fashion. Depending upon the direction in which loading is imposed (left or right as viewed in FIG. 5) the attachment of the spring 86 to the interior panel 526 will fail at 88 or 90 without failure at the other, changing the resistance of the overall trim pillar 524 to deformation.
In each of the embodiments shown, the energy absorbing capability of the structural pillars of the automotive vehicle 10 is improved over the prior art through the provision of an interior trim pillar that carries an energy absorbing medium and is fixedly secured to the body structure in a complementary fashion. This improved structure may, in some situations permit economies in the design of the structural pillars because of the added function provided by the improved trim pillars.
While only certain embodiments of the pillar structure of the present invention have been shown and described, others may be occur to those skilled in the automotive vehicle body arts which do not depart from the scope of the appended claims.
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An improved structure is provided for supporting pillars of automotive vehicles which provides energy absorption through provision of a pair of energy absorbing chambers (52,50) defined by an interior trim pillar (28) and interior (26) and exterior (24) panels forming the "A" pillar of a vehicle (10), respectively. Energy absorbing media (30), such as springs (76,78,86), elongated tubes (84) and viscous fluids are taught for use as energy absorbers.
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FIELD OF INVENTION
This invention relates to an improved method of washing the product from an alkaline peroxide treatment process for delignifying and bleaching nonwoody lignocellulosic agricultural residues, and more particularly to washing the product from a process for converting such residues into cellulosic fiber products suitable as a source of reduced calorie dietary fiber for human consumption.
The reduced calorie dietary fiber is characterized by high dietary fiber content and low contents of proteinaceous, fatty and ash-forming materials. It is suitable as a substitute for farinaceous flour at high replacement levels.
BACKGROUND
Various processes are known for converting woody and nonwoody lignocellulosic substrates into fibrous products suitable for ingestion by animals and humans.
Cattle, sheep and other ruminants are able to digest and grow on many kinds of cellulosic plant materials that provide little or no nourishment to humans and other monogastrics. Even the ruminants, however, have limited ability to efficiently digest lignocellulosic materials such as the leaves and stalks of grain-bearing grasses and the husks and hulls of the grain. This low conversion efficiency has been attributed to the close association of lignin with the cellulosic and hemicellulosic fibers in these materials. This lignin makes these cellulosics largely unavailable for digestion by the digestive juices and the microbes that inhabit ruminant stomachs. (See Jelks, U.S. Pat. No. 3,939,286 and Gould, U.S. Pat. No. 4,649,113).
Human inability to digest and assimilate cellulose and hemicellulose makes the substrates attractive as potential sources of dietary fiber. But, widespread use for this purpose has been hampered by the lignin that envelops the cellulosic fibers, by the highly crystalline character of the fibers and by the presence of components such as fatty substances (fats and oils) and ash-forming substances (including silicaceous materials). The crystalline character imparts undesirable physical properties to foodstuffs and the fatty and ash-forming substances, especially when used in relatively high proportions, adversely effect the aroma, taste, texture and mouthfeel of food products.
One lignocellulosic material used as a dietary fiber is bran, the unbleached coarse outside covering of the seeds or kernels of cereal grains. Bran is used as fiber or roughage in some breakfast foods, breads and muffins. But, most of the bran is used in animal food, primarily because its high non-cellulosic content adds undesirable properties to many kinds of baked goods, particularly to white bread.
Low calorie flour substitutes made by grinding hulls of oats and other cereal grains (see Tsantir et al., U.S. Pat. No. 3,767,423) contain relatively large proportions of non-cellulosic components such as ash-forming substances. At desirably high flour replacement levels, food products in which they are used have a gritty aftertaste. For this reason, commercial interest has shifted largely to purified cellulose as a dietary fiber for human consumption.
Two forms of purified cellulose, both derived from wood products, are currently available. They are crystalline alpha cellulose, sold under the trade name "Solka-Floc", and microcrystalline cellulose, derived from alpha cellulose, sold under the trade name "Avicel". These products, however, are not entirely satisfactory as flour substitutes (See Glicksman et al., U.S. Pat. No. 3,676,150; Satin, U.S. Pat. No. 4,237,170; Tsantir et al., U.S. Pat. No. 3,767,423; and Torres, U.S. Pat. No. 4,219,580). The taste and texture of baked goods is adversely effected at flour replacement levels greater than about 20 percent.
Gould, U.S. Pat. No. 4,649,113 (1987), discloses a process (Gould Process) for converting nonwoody lignocellulosic agricultural residues (substrate) such as wheat straw into cellulosic fiber products digestible by ruminants and microbes. Gould et al., European Patent Application No. 228951 (1987), discloses that the delignified fiber products of U.S. Pat. No. 4,649,113 are also suitable as noncaloric fiber additives to compositions intended for consumption by humans.
The Gould Process involves slurrying the substrate in aqueous hydrogen peroxide (H 2 O 2 ) and alkali (NaOH) at a pH of 11.2 to 11.8 and a temperature of 5° to at least 60° C. The substrate is sufficiently delignified exposing virtually all the cellulosic carbohydrates. During the alkaline peroxide treatment, the pH of the reaction medium drifts upward and is controlled by the addition of acid. The H 2 O 2 assists in the delinginfication of the substrate by oxidizing and degrading lignin to low molecular weight water-soluble compounds, principally carboxylic acids.
Gould et al. teaches that the products can serve as wheat flour substitutes at high (30% or more) replacement levels.
Although attractive as a means of converting substrates to food formulations for ruminants and humans, the Gould Process is not entirely satisfactory for commercial use. It requires rather high concentrations of both H 2 O 2 and NaOH based on the substrate and suffers high and losses of H 2 O 2 through nonfunctional (nonproductive) decomposition to oxygen gas (2 H 2 O 2 ←2 H 2 O+O 2 ). Also, we have found that the process when used to treat difficult substrates such as oat hulls results in a rapid decrease in the concentration of the H 2 O 2 , accompanied by excessive initial foaming of the reaction mixture, and the production of products that have undesirable quality (brightness, taste and aroma) for human consumption.
Decomposition of H 2 O 2 in a highly alkaline heterogeneous reaction medium, such as when a particulate substrate is present, is not too surprising for a couple of reasons. First, H 2 O 2 is known to be unstable in alkali, particularly at high pH. Second, heterogeneous H 2 O 2 decomposition into H 2 O and O 2 (catalyzed by solid surfaces) is generally far faster than homogeneous decomposition (catalyzed by a variety of soluble, mostly cationic substrates), with the rate increasing in proportion to the surface area of the solids (see Schumb et al., Hydrogen Peroxide, ACS Monograph Series, New York, Rheinhold (1955) pp 521-522).
In a copending application to Jayawant (No. CH-1459) assigned to E. I. du Pont de Nemours & Company, an improvement over the process of U.S. Pat. No. 4,649,113 is taught for converting nonwoody substrates, particularly nonwoody lignocellulosic agricultural residues, into cellulosic fiber products useful as a source of carbohydrates digestible by ruminants and as a source of low calorie dietary fiber ingestible by humans. The process broadly comprises treating lignocellulosic substrates in an aqueous solution of strong alkali (Alkaline, Peroxide-Free Stage) for a period of time prior to the addition of peroxide (Alkaline-Peroxide Stage).
In a copending application to Chou et al. (No. CH-1514) assigned to E. I. du Pont de Nemours & Company, a further improvement over the process of U.S. Pat. No. 4,649,113 is taught. In that application, the process broadly comprises separating the substrate from the alkaline liquor following the Alkaline, Peroxide-Free Stage, reslurrying the substrate and treating it in the Alkaline-Peroxide Stage at a pH of 8.5 to 11.0.
Both the copending applications and U.S. Pat. No. 4,649,113 are incorporated herein by reference.
BRIEF DESCRIPTION OF THE INVENTION
It has now been found that the product of the copending applications (Nos. CH-1459 and CH-1514) as well as that of U.S. Pat. No. 4,649,133 can be significantly brightened, ash content can be lowered and any hydrogen peroxide or alkali metal ions and water-soluble organic compounds that might be present with the product can be minimized by acid washing the product separated from the alkaline-peroxide liquor. Further steps of hydrogen peroxide decomposition required to make a product for human consumption can be avoided. Baked products made from flours having the resulting product present in high replacement levels (greater than 20 percent and even at levels as high as 40 percent) have been found to perform well in bake tests achieving high bake scores with particularly good aroma and taste.
Sufficient dilute acid should be used to lower and maintain the pH of the bleached, delignified non-woody lignocellulosic material at less than about 3.0 for a sufficient time and under conditions that assure full soaking of the substrate with acid at that pH. Following the acid soak time, the product is washed one or more times to sufficiently remove water-soluble organic compounds and residual chemicals, including free acids, and the product is dried. Preferably the pH after the removal of the residual chemicals, that is, after the last wash is about 4.0 to 7.0.
DETAILED DESCRIPTION OF INVENTION
The invention comprises an improved process for improving the fiber products from a process for converting a nonwoody lignocellulosic material (Substrate) into products digestible by ruminants and ingestible by humans. In particular, the process's main advantage is that is substantially brightens the product and lowers ash, hydrogen peroxide and alkali metal ion content which is desirable for dietary human foods. By improving the fiber product, the baked products made therefrom are also improved. The process comprises the following steps:
(a) Upon completion of the alkaline peroxide treatment, separating the insoluble cellulosic fiber product from the aqueous alkaline peroxide phase and optionally washing it with water one or more times to remove residual chemicals including alkali metal base and water-soluble compounds,
(b) After optional initial water washes, adding enough acid to lower the pH to less than about 3.0, preferably 2.0-2.5,
(c) Holding the product at that pH with adequate mixing to assure full soaking of the product for a time sufficient to remove chemical residues and enhance product brightness,
(d) Following the hold time at the low pH, washing the product a sufficient number of times to remove chemical residues, including free acids, and water-soluble compounds, and
(e) Separating the product from the wash liquid, and
(f) Preferably drying the separated product.
Any aqueous mineral acid or organic acid that is non-toxic, such as hydrochloric, nitric, sulfuric, citric, tartaric and acetic acid, can be used. Preferably hydrochloric acid is used.
Preferably the acid added is dilute having a pH of about 2. Stronger acids may be added in that they can effectively brighten the product and remove undesired components. Stronger acids (pH's below 2), however, may cause the pH of the soaked substrate to be lowered to less than 2.0. While this is within the range of equivalents envisioned, a significantly higher number of washes, with an economic penalty, will be needed to remove the residual chemicals, including free acids, if the pH of the substrate is lowered to less than 2.0.
The pH of the soaked substrate should be lowered to less than about 3, preferably between about 2.0 and 2.5. The pH of the substrate and the pH of the filtrate will be approximately equal when the substrate is fully soaked.
With normal mixing, about 15 to 30 minutes should be sufficient to assure full soaking of the product. With high efficiency mixing, shorter soak times can be used.
Temperature of the soaking step is not critical and can be room temperature (23° to 25° C.) or higher. At higher temperatures, shorter soak times can be used.
Washing preferably is done with fresh process water. The sufficiency of the washing step to remove the chemical residues, including free acids, can be measured by techniques known to those skilled in the art. For example, conductivity or pH measurement can be used. The conductivity of the liquid leaving the last wash being close to the conductivity of the "pure" wash liquid entering that wash indicates that most of the chemical residue has been removed. The preferred pH at the end of the last wash preferably is 4.0 to 7.0.
The separated product preferably is dried in any conventional drier such as a rotary drier, a fluid bed drier, a pan drier or a spray drier. More preferably, the separated product is dewatered, for example, by pressing or by centrifugation before being dried in the drier. Drying temperatures depend on the type of drier but should be high enough to efficiently dry, but low enough to avoid charring or darkening of the product. Preferably, product temperatures should not exceed 105° C.
For human dietary fiber products, in addition to removal of lignin, removal of residual nutritive proteins fats oils and ash-formers is important. Reducing the nutritive content is needed if the product is to qualify as "dietary", that is, as a low calorie or non-fattening food. Reducing fats, particularly unsaturated fats, is needed to avoid objectionable aroma and a rancid taste in baked goods. Reducing the ash-forming substances is needed to avoid objectionable mouthfeel (gritty taste and texture) in baked goods.
The dried product can be ground for use as a dry ruminant feedstuff or dietary fiber for substitution at high replacement levels in flour used to make cakes, breads, pasta, pizza and other baked goods for human consumption. It can also be generally used in foods as a process aid, a anticaking agent, a binding agent or carrier. It can be used as a pharmaceutical excipient.
Particularly in the case of a dietary fiber, the product of this invention is preferably fine ground by itself or co-ground with the regular flour with which it ultimately is to be mixed. Degree of grinding effects mouthfeel of baked products containing the fiber. Regular flour can be any flour such as wheat flour, corn flour, rice flour, rye flour or oat flour and need not be from the same plant as the fiber of this invention. The co-grinding or milling may optionally be done after preblending the product and the grain. The blending and grinding preferably are performed in a manner to give uniformly distributed mixtures of regular and dietary fiber flours.
In preferred embodiments of the invention, flour substitutes having low levels (in weight %) of proteins (less than 1), fatty substances (less than 0.1) and ash-forming substances (less than 2.5) including the silicaceous material, taken as SiO 2 , (less than 1) and high brightness are produced. Also, products with low levels of alkali metal ion (about 100 ppm as Na + ) and of hydrogen peroxide (less than 3 ppm) are produced.
In preferred embodiments of the invention designed to provide bleached cellulosic fiber products for use as low calorie dietary flour substitutes, the degree of whiteness of the bleached product, or its brightness value, should be high to meet the demands of the white flour industry. The brightness, as determined with a Hunter Color Difference Meter, Model D-2, of the dry product tamped flush with the rim of a round 6 cm diameter by 1.8 cm deep metal can, should be at least about 75, preferably about 80 or more. In comparison, the unbleached substrates have brightness values around 65 or less.
EXAMPLES
The following examples are intended only to further illustrate the invention and are not intended to limit the scope of the invention.
Examples 1 to 9 show the process of copending application to Chou et al. (No. CH-1514) including recycle of both the alkali and the peroxide and the acid washing of delignified and bleached oat hulls claimed in this application (No. CH-1564). Examples 10 to 14 show the treatment of product made according to the process of copending application to Jayawant (No. CH-1459) and that the brightness enhancement depends on the pH obtained with the acid wash. Example 15 shows the results of bake tests using product made according to Examples 1 to 9 at high replacement levels (40 weight %).
EXAMPLE 1
One hundred grams (oven-dried weight) at 91.3% consistency of slightly shredded oat hulls having a small amount of fines (109.5 grams) were added to 890.5 grams of process water obtained from a city potable water supply to make a 10 wt. % slurry. The slurry was stirred at room temperature (23°-25° C.) for 15 minutes and then filtered without pressing.
The filtered solids were then reslurried in enough process water to make a 1000 gram slurry which was heated to 65° C. Sodium hydroxide (20.5 grams of 48.8 wt. % NaOH solution) was added to the slurry and stirred for 1/2 hour at 65° C. and a pH of 11.86. On a 100 wt. % basis, the NaOH added was 10 wt. % of the dry weight of the hulls. The solids were then filtered without pressing. The filtrate (Alkaline Filtrate) was saved for recycling.
The wet solids were then reslurried in enough process water to make a 1000 gram slurry which was heated to 65° C. and found to have a pH of 10.84. Hydrogen peroxide (21.5 grams of a 32.6 wt. % H 2 O 2 solution) was then added to the slurry which was stirred for 2 hours with the temperature controlled at about 65° C. (temperature varied from 63° to 65° C.). On a 100 wt. % basis, the H 2 O 2 added was 7 wt. % of the dry weight of the hulls. The pH was measured every 15 minutes. It dropped to 9.22 by the end of the 2 hours.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.6530% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%).
The filter cake was then washed five times with 500 milliliters of process water. Following the fifth wash, the filter cake was reslurried in process water to make 1000 grams of slurry. Enough hydrochloric acid was added to lower the pH to and maintain it at 2.2 to 2.4 for 15 minutes. The solids were then filtered but not pressed (except for the last wash) and washed five times with 500 ml of process water each time. After the last wash, the solids were pressed to remove as much liquid as possible and then dried in a fluid bed dryer.
The dried product was found to have a brightness of 77.5, an ash content of 1.99%, a sodium ion content of 71 parts per million (ppm), a SiO 2 content of 0.82%, and hydrogen peroxide content of 2.7 ppm. Yield loss was 29.3%.
EXAMPLE 2
The procedure of Example 1 was repeated except that recycled NaOH and H 2 O 2 were used. Instead of fresh NaOH solution, 655.3 grams (2.8 grams of 100% NaOH) of the Alkaline Filtrate from Example 1 was used. 14.8 grams of fresh 48.8% NaOH solution (7.2 grams of 100% NaOH) was added to adjust the NaOH concentration to 10 wt. % of the dry weight of the hulls. Instead of fresh H 2 O 2 solution, 495.2 grams (3.2 grams of 100% H 2 O 2 ) of the Peroxide Filtrate from Example 1 was used. 11.7 grams of fresh 32.6% H 2 O 2 solution (3.8 grams of 100% H 2 O 2 ) was added to adjust the H 2 O 2 concentration to 7 wt. % of the dry weight of the hulls.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.5543% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%).
The dried solids were found to have a brightness of 78.8, an ash content of 2.47%, a sodium ion content of 134 ppm, a SiO 2 content of 0.98%, and hydrogen peroxide content was non-detectable. Yield loss was 30.2%.
EXAMPLE 3
The procedure of Example 1 was repeated except that recycled NaOH and H 2 O 2 were used. Instead of fresh NaOH solution, 663.9 grams (3.19 grams of 100% NaOH) of the Alkaline Filtrate from Example 2 was used. 11.9 grams of fresh 48.8% NaOH solution (5.8 grams of 100% NaOH) was added to adjust the NaOH concentration to 9 wt. % of the dry weight of the hulls. Instead of fresh H 2 O 2 solution, 461.3 grams (2.4 grams of 100% H 2 O 2 ) of the Peroxide Filtrate from Example 2 was used. 14.1 grams of fresh 32.6% H 2 O 2 solution (4.6 grams of 100% H 2 O 2 ) was added to adjust the H 2 O 2 concentration to 7 wt. % of the dry weight of the hulls.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.6156% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%).
The dried solids were found to have a brightness of 77.3, an ash content of 2.03%, a sodium ion content of 123 ppm, a SiO 2 content of 0.77%, and hydrogen peroxide content of 2.2 ppm. Yield loss was 26.7%.
EXAMPLE 4
The procedure of Example 1 was repeated except that recycled NaOH and H 2 O 2 were used. Instead of fresh NaOH solution, 645.7 grams (5.3 grams of 100% NaOH) of the Alkaline Filtrate from Example 3 was used. 11.9 grams of fresh 48.8% NaOH solution (5.3 grams of 100% NaOH) was added to adjust the NaOH concentration to 8 wt. % of the dry weight of the hulls. Instead of fresh H 2 O 2 solution, 559.1 grams (2.9 grams of 100% H 2 O 2 ) of the Peroxide Filtrate form Example 3 was used. 12.6 grams of fresh 32.6% H 2 O 2 solution (4.1 grams of 100% H 2 O 2 ) was added to adjust the H 2 O 2 concentration to 7 wt. % of the dry weight of the hulls.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.4948% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%).
The dried solids were found to have a brightness of 77.3, an ash content of 2.20%, a sodium ion content of 123 ppm, a SiO 2 content of 0.83%, and hydrogen peroxide content was non-detectable. Yield loss was 25.9%.
EXAMPLE 5
The procedure of Example 2 was repeated except that recycled NaOH and H 2 O 2 were used. Instead of fresh NaOH solution, 661.2 grams (2.6 grams of 100% NaOH) of the Alkaline Filtrate from Example 4 was used. 13.1 grams of fresh 48.8% NaOH solution (6.4 grams of 100% NaOH) was added to adjust the NaOH concentration to 9 wt. % of the dry weight of the hulls. Instead of fresh H 2 O 2 solution, 699.1 grams (2.7 grams of 100% H 2 O 2 ) of the Peroxide Filtrate from Example 4 was used. 13.2 grams of fresh 32.6% H 2 O 2 solution (4.3 grams of 100% H 2 O 2 ) was added to adjust the H 2 O 2 concentration to 7 wt. % of the dry weight of the hulls.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.3552% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%)
The dried solids were found to have a brightness of 76.8, an ash content of 1.82%, a sodium ion content of 127 ppm, a SiO 2 content of 0.67%, and hydrogen peroxide content of 1.9 ppm. Yield loss was 27.8%.
EXAMPLE 6
The procedure of Example 1 was repeated except that recycled NaOH and H 2 O 2 were used. Instead of fresh NaOH solution, 642.2 grams (2.9 grams of 100% NaOH) of the Alkaline Filtrate from Example 5 was used. 14.5 grams of fresh 48.8% NaOH solution (7.1 grams of 100% NaOH) was added to adjust the NaOH concentration to 10 wt. % of the dry weight of the hulls. Instead of fresh H 2 O 2 solution, 489.5 grams (1.7 grams of 100% H 2 O 2 ) of the Peroxide Filtrate from Example 5 was used. 16.3 grams of fresh 32.6% H 2 O 2 solution (5.3 grams of 100% H 2 O 2 ) was added to adjust the H 2 O 2 concentration to 7 wt. % of the dry weight of the hulls.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.3580% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%).
The dried solids were found to have a brightness of 75.3, an ash content of 1.79%, a sodium ion content of 168 ppm, a SiO 2 content of 0.51%, and hydrogen peroxide content was non-detectable. Yield loss was 26.1%.
EXAMPLE 7
The procedure of Example 1 was repeated except that recycled NaOH and H 2 O 2 were used. Instead of fresh NaOH solution, 697.7 grams (3.7 grams of 100% NaOH) of the Alkaline Filtrate from Example 6 was used. 12.9 grams of fresh 48.8% NaOH solution (6.3 grams of 100% NaOH) was added to adjust the NaOH concentration to 10 wt. % of the dry weight of the hulls. Instead of fresh H 2 O 2 solution, 404.9 grams (1.1 grams of 100% H 2 O 2 ) of the Peroxide Filtrate from Example 6 was used. 18.1 grams of fresh 32.6% H 2 O 2 solution (5.9 grams of 100% H 2 O 2 ) was added to adjust the H 2 O 2 concentration to 7 wt. % of the dry weight of the hulls.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.5098% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%).
The dried solids were found to have a brightness of 77.0, an ash content of 1.68%, a sodium ion content of 115 ppm, a SiO 2 content of 0.66%, and hydrogen peroxide content of 2.5 ppm. Yield loss was 26.1%.
EXAMPLE 8
The procedure of Example 1 was repeated except that recycled NaOH and H 2 O 2 were used. Instead of fresh NaOH solution, 656.7 grams (3.6 grams of 100% NaOH) of the Alkaline Filtrate from Example 7 was used. 13.1 grams of fresh 48.8% NaOH solution (6.4 grams of 100% NaOH) was added to adjust the NaOH concentration to 10 wt. % of the dry weight of the hulls. Instead of fresh H 2 O 2 solution, 474.1 grams (2.2 grams of 100% H 2 O 2 ) of the Peroxide Filtrate from Example 7 was used. 14.7 grams of fresh 32.6% H 2 O 2 solution (4.8 grams of 100% H 2 O 2 ) was added to adjust the H 2 O 2 concentration to 7 wt. % of the dry weight of the hulls.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.5262% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%).
The dried solids were found to have a brightness of 77.8, an ash content of 1.55%, a sodium ion content of 165 ppm, a SiO 2 content of 0.47%, and hydrogen peroxide content was non-detectable. Yield loss was 27.9%.
EXAMPLE 9
The procedure of Example 1 was repeated except that recycled NaOH and H 2 O 2 were used. Instead of fresh NaOH solution, 672.8 grams (3.8 grams of 100% NaOH) of the Alkaline Filtrate from Example 8 was used. 12.7 grams of fresh 48.8% NaOH solution (6.2 grams of 100% NaOH) was added to adjust the NaOH concentration to 10 wt. % of the dry weight of the hulls. Instead of fresh H 2 O 2 solution, 680.9 grams (2.7 grams of 100% H 2 O 2 ) of the Peroxide Filtrate from Example 8 was used. 13.2 grams of fresh 32.6% H 2 O 2 solution (4.3 grams of 100% H 2 O 2 ) was added to adjust the H 2 O 2 concentration to 7 wt. % of the dry weight of the hulls.
At the end of the 2 hours, the solids were filtered but not pressed and the filtrate was saved for recycling (Peroxide Filtrate). The residual concentration of hydrogen peroxide in the filtrate was 0.4780% compared to the theoretical concentration that would result if all of the hydrogen peroxide were recovered (0.7606%).
The dried solids were found to have a brightness of 76.7, an ash content of 1.55%, a sodium ion content of 153 ppm, a SiO 2 content of 0.53%, and hydrogen peroxide content of 1.1 ppm. Yield loss was 29.8%.
EXAMPLE 10
Using the process of copending application to Jayawant (No. CH-1459) product was made for treatment in Examples 11 to 14 as follows:
One thousand grams (oven-dried weight) at 91.3% consistency of slightly shredded oat hulls having a small amount of fines (1095.3 grams) were added to 13,190.4 grams of deionized (DI) water at 65° C. to make a 7 weight percent (wt. %) consistency slurry. One hundred grams of 100 wt. % sodium hydroxide (NaOH) was then added as 225.7 grams of a fresh 44.3 wt. % NaOH solution. The pH of the slurry was about 11.45. After the hulls were uniformly wetted, 50 grams of 100% hydrogen peroxide (H 2 O 2 ) were then added as 153.4 grams of a 32.6% H 2 O 2 solution to the heated slurry. The slurry was agitated at 65° C. for 2 hours. The resulting reaction mixture had a pH of 10.35 and a H 2 O 2 concentration of 0.0599%.
The fibrous product was filtered off in a nutsch through cheese cloth and separated into 9 bags each weighing 340 grams and one weighing 310 grams for use in the following experiments. The results of the experiments are shown in the table that follows the examples.
EXAMPLE 11
One bag was split into two samples of about 155 grams each. One (11A) was washed 4 times with 250 grams of DI water each time at room temperature. After the fourth wash, the substrate was reslurried to a total weight of 700 grams with DI water and 1.3 grams of hydrochloric acid was added dropwise to hold the pH between 5.0 and 7.0 for 1/2 hour. The solids were then filtered (the filtrate had a pH of 6.2) and were washed 2 times with 250 grams of DI water at room temperature. The other sample (11B) was treated in the same manner except at a temperature of 90° C. in which case the filtrate had a pH of 5.75.
EXAMPLE 12
Substrate from one bag (340 grams) was placed in a Buchner funnel and washed four times with 500 milliliters (ml) of DI water and, then, was washed 12 times with DI water with sufficient hydrochloric acid to obtain a pH of 3.0 for the wash water. The pH of the filtrate was measured each time and found to drop to 9.16 after the first wash to 7.38 after the twelfth. The substrate was then washed 2 more times with 500 ml DI water and dried.
EXAMPLE 13
Substrate from one bag (340 grams) was placed in a Buchner funnel and washed four times with 500 ml of DI water and, then, was washed 10 times with DI water with sufficient hydrochloric acid to obtain a pH of 2.5 for the wash water. The pH of the filtrate was measured each time and found to drop to 9.18 after the first wash to 5.34 after the tenth. The substrate was then washed 2 more times with 500 ml DI water and dried.
EXAMPLE 14
Substrate from one bag (340 grams) was placed in a Buchner funnel and washed four times with 500 ml of DI water and, then, was washed 3 times with DI water with sufficient hydrochloric acid to obtain a pH of 2.0 for the wash water. The pH of the filtrate was measured each time and found to drop to 2.54 after the first wash to 2.12 after the third. The substrate was then washed 2 more times with 500 ml DI water and dried.
TABLE______________________________________ Bright- Ash Na.sup.+ SiO.sub.2 H.sub.2 O.sub.2 ResidueExample ness(a) (wt. %) (wt. %) (wt. %) (ppm)______________________________________11A 75.8 1.88 0.35 0.39 not measured11B 75.7 1.92 0.35 0.39 not measured12 74.5 2.11 0.45 0.41 3.213 74.5 1.95 0.38 0.44 4.414 77.1 1.50 0.09 0.45 less than 3.0______________________________________ (a)Hunter Color Difference Meter D2 ratings.
EXAMPLE 15
Bake Tests
Suitability of the product for use as a flour substitute ultimately is determined by bake tests. The product ("Fiber") made according to the process in Examples 1 through 9 were submitted for such tests which were run according to the following procedure:
1. The product ("Fiber") was mixed with wheat (white bread) flour at a 40 weight percent replacement level.
2. Bread was made by the "Sponge and Dough" method under standard baking conditions. A sponge was first made by mixing the following ingredients in a Hobart A-120 mixer with a McDuffee bowl and a three-prong hook for 1 minute at the low (no. 1) speed and then for 1 minute at the middle (no. 2) speed at 77°±1° F.:
______________________________________Ingredients Weight (grams)______________________________________Bakers Patent Flour 300Fiber.sup.(a) 200Vital Yeast Glutton 30Mineral Yeast Food 3PD-321 2.5XPANDO 5Compressed Yeast 15Water 700.sup.(b)______________________________________ .sup.(a) Laboratory Pin Milled .sup.(b) cubic centimeters
The sponge was fermented in a fermentation box for 3 hours at 86° F. and 85% relative humidity and then remixed with the following additional "Dough" ingredients for 1 minute at No. 1 speed and then to development at No. 2 speed (about 10 minutes):
______________________________________Ingredients Weight (grams)______________________________________Bakers Patent Flour 200Vital Wheat Glutton 30Salt 15Calcium Propionate 2.5Compressed Yeast 10High Fructose Corn Syrup 35.sup.(a)Water 100.sup.(a)Ascorbic Acid 10.sup.(a)______________________________________ .sup.(a) cubic centimeters
The remixed dough was allowed to rest in the fermentation box for 10 minutes at 86° F. and 85% relative humidity and was then divided into 520 gram pieces, rounded by hand, molded in a cross grain molder and proofed at 110° F. and 81% relative humidity for about 1 hour until it had doubled in size. The loaves were then baked at 430° F. for 18 minutes in pans having top inside dimensions of 43/8 inches by 10 inches, bottom outside dimensions of 43/4 inches by 93/4 inches and a depth of 23/4 inches.
3. A "Score" was determined for the loaves by trained laboratory personnel in the baking laboratory. They evaluated the height of the loaf (50), color (10), aroma (10), taste (10), graininess (10), and texture (10) Each criteria is measured against the maximum point value in the parentheses. The total point value for all the criteria is 100.
The bread baked using the product of the process in which no alkali or peroxide are recycled and that using the product from the recycling processes had the same bake scores. The breads predictably had decreased height, texture and graininess ratings because the fiber was laboratory pin milled. Finer grinding, particularly if the Bakers Patent Flour and the product were co-ground, would be expected to yield a bread with improved height, texture and graininess having a total score in excess of 90. The ratings were: Height --40, Color --8, Aroma --8, Taste --8, Graininess --6, and Texture --6 for a total score of 76. The bread had 40 calories per 28 grams.
As a comparison Colonial Standard "Lite Bread", a commercial low calory bread containing half the fiber and having 40 calories per 21 grams was used a the standard with the following ratings: Height --50, Color --10, Aroma --10, Taste --10, Graininess --10, and Texture --10 for a total score of 100.
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An improved process of purifying the product from an alkaline peroxide treatment process for delignifying and bleaching nonwoody lignocellulosic agricultural residues comprising, optionally washing with water, then lowering and maintaining the pH of the substrate at less than about pH 3.0, then washing sufficiently to remove residual chemicals, separating the product from the wash liquid and, optionally, drying the product.
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BACKGROUND OF THE INVENTION
This invention relates generally to methods and apparatus for servicing refrigeration systems and more particularly concerns the recovery of refrigerants from such systems without release of refrigerant to the atmosphere.
Predecessors to the present refrigerant recovery system are disclosed in my earlier U.S. Pat. No. 5,320,224 and patent application Ser. No. 134,045, soon to be issued as a patent. While the previous systems perform quite well in that the series arrangement of vacuum pump and compressor facilitates achievement of a deep vacuum in the disabled unit, a cryogenic type of pressure regulator was required to protect the vacuum pump. As a result, while otherwise unachievable vacuum levels for this kind of equipment were obtained, the operation of the system was slowed considerably.
In addition, in switching earlier refrigerant recovery systems from liquid to vapor evacuation, three-way valves requiring manual operation were employed. In some applications, when the operator failed to switch the valve from liquid to vapor flow before starting the compressor, the result was severe damage to the compressor.
Moreover, none of the earlier systems, regardless of their efficiency, permitted evacuation of the repaired disabled unit to the atmosphere through the same vacuum pump that had been used to evacuate the unit for repair. This lack further increased complexity of and time on the job.
At the same time, solutions to these problems give rise to a variety of difficulties in devising a refrigerant recovery unit useable to recover both liquid refrigerant and gaseous refrigerant from a disabled unit, to evacuate a refrigerant receiving can and to evacuate the repaired disabled unit and the recovery unit to a deep vacuum.
It is, therefore, an object of this invention to provide a refrigerant recovery unit capable of performing the evacuation of liquid and gaseous refrigerant from the disabled unit as well as the evacuation of receiving cans and of the refrigerant recovery unit itself. It is also an object of this invention to provide a refrigerant recovery unit capable of performing this multitude of functions with the gaseous refrigerant evacuation process proceeding at faster rates than in earlier systems. It is another object of this invention to provide a refrigerant recovery system which automatically transfers from the liquid recovery to the gaseous recovery flow conditions when the condenser is switched on. And it is an object of this invention to provide a refrigerant recovery unit which permits evacuation of a repaired refrigeration unit to the atmosphere using the same vacuum pump used during the refrigerant evacuation process prior to repair.
SUMMARY OF THE INVENTION
In accordance with the invention, a refrigerant recovery unit is provided in which four distinct refrigerant flow paths are automatically controlled by the unit components to perform four separate and distinct functions. In a liquid refrigerant path, liquid refrigerant is recovered from the discharge side of a disabled unit through the refrigerant recovery unit by use of the differential pressure between the disabled unit and the refrigerant receiving can. In a primary vapor path, evacuation of gaseous refrigerant from the high and low sides of the disabled unit is achieved by use of a compressor in the recovery unit which produces a differential pressure to induce flow. This differential pressure is produced solely by the recovery unit compressor until such time as the intake pressure of the compressor reaches approximately 4 inches Hg. vacuum. When the compressor intake pressure reaches 4 inches Hg. vacuum, the system automatically switches to a secondary vapor path for recovering gaseous refrigerant from the high and low side of the disabled unit by sequencing an external vacuum pump in series with the compressor of the recovery unit to produce the differential pressure inducing flow. This differential pressure is continued until the intake pressure reaches a desired vacuum level of up to 29.9 inches Hg. Finally, to recover gaseous refrigerant or non-condensible gas from the high and low side of the disabled unit after the desired vacuum level has been reached, differential pressure is obtained by connecting the external vacuum pump through the recovery unit without using the compressor. This same path can be used to remove non-condensible gas from a receiving can as well. Since the vacuum pump is sequenced into operation with the compressor, the need for the cryogenic type pressure regulator to protect the pump is eliminated and the speed of the gaseous refrigerant's evacuation process is accelerated to approximately one-sixth (1/6) the time of previously known units.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
FIG. 1 is a block diagram of a preferred embodiment of the improved refrigerant recovery unit;
FIG. 2 is a schematic diagram of the preferred embodiment of the common inlet flow path of the refrigerant recovery unit;
FIG. 3 is a schematic diagram of a preferred embodiment of the liquid flow path of the refrigerant recovery unit;
FIG. 4 is a schematic diagram of a preferred embodiment of the common outlet flow path of the refrigerant recovery unit;
FIG. 5 is a schematic diagram of a preferred embodiment of the primary vapor flow path of the refrigerant recovery unit;
FIG. 6 is a schematic diagram of a preferred embodiment of the common vapor flow path of the refrigerant recovery unit;
FIG. 7 is a schematic diagram of a preferred embodiment of the secondary vapor path of the refrigerant recovery unit;
FIG. 8 is a schematic diagram of a preferred embodiment of the electrical system of the refrigerant recovery unit; and FIG. 9 is a schematic diagram of the unit of FIG. 1
While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning to FIG. 1, the basic flow paths for the evacuation of refrigerant from a disabled unit to a receiving can are illustrated. Refrigerant passes from the disabled unit into a common inlet path 10 and from the common inlet path 10 to a flow path branch point A. From branch point A, refrigerant in the liquid form flows through a liquid path 30 and then via a branch point B through a common outlet path 50 which is connected to the receiving can. If the refrigerant is in a gaseous state, it will flow from the branch point A through a primary vapor path 70 to a branch point C at which it is directed to a common vapor path 90 which in turn connects to the branch point B entering into the common outlet path 50 which also receives the liquid refrigerant. In the primary vapor path 70, refrigerant is evacuated to a first predetermined vacuum level. When this level has been reached, flow automatically transfers from the branch point A through a secondary vapor path 130 to the branch point C and thence through the common vapor path 90 to branch point B and the common outlet path 50. In the secondary vapor path 130, refrigerant can be evacuated to a second predetermined vacuum level significantly deeper than the first predetermined vacuum level.
Looking at FIG. 2, the components of the common inlet path 10 are illustrated in greater detail. In this path, a first hose 11 is connected from the high side of the disabled unit compressor and a second hose 13 connected from the low side of the disabled unit compressor. These hoses 11 and 13 are then connected to the high side and low side ports, respectively, of the manifold gauge 15. A sight glass and filter dryer are mounted on the manifold gauge 15 which is then connected to the inlet side of a recovery unit intake valve 17. The outlet side of the intake valve 17 is connected to the flow path branch point A of the recovery unit.
Looking at FIG. 3, the components of the liquid flow path 30 of the recovery unit are shown in greater detail. From the branch point A, the flow path 30 is connected to a low side pressure gauge 31 and thence to a check valve 33 which is in turn connected to flow path branch point B of the recovery unit.
As shown in FIG. 4, the components of the common outlet path 50 of the recovery unit extend from the flow path branch point B and include a solenoid valve 51 connected in series through a discharge valve 53 to the receiving can intake.
Looking at FIG. 5, the components of the primary vapor path 70 of the recovery unit extend from the flow path branch point A and include a second solenoid valve 71 in series with a second check valve 73 to flow path branch point C of the recovery unit.
The components of the common vapor path 90 are illustrated in greater detail in FIG. 6. From flow path branch point C of the recovery unit, gaseous refrigerant flows into an oil separator 91 which has an oil drain valve 93 for removal of oil collected in the separator 91. From the separator 91 gaseous refrigerant continues to flow through a pressure regulator 95 to a T-connector 97. From the T-connector 97, the pressure is monitored by a high pressure switch 99 set at approximately 4 inches Hg. vacuum as the gaseous refrigerant continues to flow to the compressor 101. From the compressor 101 flow continues to the oil return separator 103. From the oil return separator 103, oil return can be accomplished through another solenoid valve 105 which connects the separator 103 back to the T-connector 97. Normally the refrigerant flows from the oil return separator 103 to a condensing coil 107 after which it is monitored by an approximately 420 psig pressure switch 109 as flow continues through a high side pressure gauge 111 and thence through a check valve 113 to the flow path branch point B of the recovery unit.
The components of the secondary vapor path 130 are illustrated in greater detail in FIG. 7. As shown, from flow path branch point A of the recovery unit, gaseous refrigerant flows through a solenoid valve 131 and thence through an intake valve 133 which is connected to the intake port of a vacuum pump 135. Since the vacuum pump 135 is a relatively cumbersome piece of equipment and since disabled unit owners often have a suitable vacuum pump 135 available on site, the vacuum pump 135 is typically external to the refrigerant recovery unit. From the discharge port of the vacuum pump 135, flow of gaseous refrigerant continues through a port 137 to the vacuum pump discharge and then to another check valve 139 which in turn is connected to the flow path branch point C of the recovery unit. Between the port 137 and the check valve 139, an approximately 20 psig switch 141 and a vacuum pump valve 143 useable to vent the vacuum pump discharge to the atmosphere are connected.
Turning now to FIG. 8, the electrical system of the recovery unit is illustrated. As shown, first and second conductors 151 and 153 provide power to the system from a 115 AC source (not shown). The circuit includes the coil of the outlet flow path solenoid valve 51 connected at one end to the first conductor 151 and at the other end to a common point 154. A double pole, double throw power switch 155 is variably selectable between first and second RECOVER positions 157 and 159, first and second OFF positions 161 and 163, and first and second VACUUM positions 165 and 167. The first RECOVER position 157 and first VACUUM position 165 are connected in common to the 20 psig pressure switch 141 in the secondary vapor path 130 and then in series with the 420 psig pressure switch 109 in the common vapor path 90 and the main coil 169 of the circuit which is in turn connected to the common point 154 on the output side of the coil of the outlet flow path; solenoid valve 51. The common point 154 is then connected through a neon light 171 to the second conductor 153. A bottle switch 173 is connected in parallel with the neon light 171. The second RECOVER terminal 159 of the power switch 155 is connected in series to a contact 175 operated by the main coil 169, to the electrical circuit of the compressor 101 and fan (not shown) and then to the second conductor 153. Connected in parallel with the contact 175 and the circuit of the compressor 101 and fan is a series arrangement of the 4 inch Hg. vacuum switch 99 of the common vapor path 90 and a vacuum relay coil 177. A second switch 181 connected to the first conductor 151 has first and second ON positions 183 and 185, respectively, and first and second OFF positions 187 and 189, respectively. The first ON terminal 183 is connected through the coil of the solenoid valve 105 in the common vapor path 90 to the second conductor 153. The second 0N terminal is connected through the coil of the solenoid valve 71 in the primary vapor path 70 to the second conductor 153. In addition, the second on position of the switch 181 is connected in parallel with a series connection of a contact 191 of the main coil 169 in series with a first position 193 of another switch 195. A second position 197 of the switch 195 is connected through the coil of the solenoid 131 in the secondary vapor path 130 of the recovery unit to the second conductor 153. Connected in parallel with the coil of the solenoid valve 131 in the secondary vapor path is a series arrangement of a breaker 199 and a power source receptacle for the vacuum pump 135 of the secondary vapor path 130. The breaker 199 protects the internal circuits when the vacuum pump 135 is activated.
To connect the recovery unit between the disabled unit or other refrigerant source and the receiving can or other refrigerant receptacle, the sight glass and filter dryer associated with the manifold 1,5 are connected together and mounted to the recovery unit intake valve 17. The hoses 11 and 13 are connected between the compressor of the disabled unit and the manifold 15 and another hose connected between the manifold gauge 15 and the intake valve 17. Another hose is connected between the recovery unit discharge valve 53 and the vapor valve of the receiving can. In addition, a safety cord (not shown) is connected to a safety switch on the receiving can (not shown). The power conductors 151 and 153 are then connected via the power cord (not shown) to the 115 volt power supply (not shown). This completes the basic connection of the recovery unit between the disabled unit and the receiving can.
To complete connection of the system, the vacuum pump 135, which is ordinarily external to the system, must also be connected. A first hose is connected between the vacuum port intake 133 and the vacuum port of the vacuum pump 135. A second hose is connected between the discharge port of the vacuum pump 135 and the port 137 to vacuum pump discharge. The vacuum pump 135 is then plugged into the vacuum pump power source receptacle as shown in FIG. 8. The intake valve 133 is then turned on and the vacuum pump. switch (not shown) is turned to the ON position. This completes the vacuum pump connection to the system.
In operation, after the system is connected, the high side valve (not shown) between the disabled unit and the manifold gauge 15 is opened. The intake valve 17 and the discharge valve 53 on the recovery unit are also opened, as is the vapor valve (not shown) on the receiving can. All valves on the refrigerant hoses will also be open. If the neon light 171 shows ON in this condition, this indicates that either the receiving can safety cord (not shown) is not properly connected, that the receiving can is not in upright condition, or that the receiving can is eighty percent (80%) full. When appropriate corrective action has been taken, the neon light should be in the OFF condition and the bottle switch 173 associated with the receiving can will be closed. Thus the coil of the solenoid valve 51 in the outlet flow path 50 will be energized and the solenoid valve 51 is in the open condition so that refrigerant in the liquid state will rush from the disabled unit to the receiving can as a result of the differential pressure between the disabled unit and the receiving can. By checking the sight glass associated with the manifold 15, it can be determined whether the flow of liquid refrigerant has ceased. If flow has ceased, the low side valve (not shown) on the disabled unit and the manifold are opened and the power switch 155 is moved from its OFF positions 161 and 163 to its RECOVER positions 157 and 159. The 20 psig switch 141 and the 420 psig switch 109 are closed, and therefore the main coil 169 is energized. This in turn causes the compressor main contact 175 to close, thus energizing the compressor circuit 101. At the same time, the vacuum relay switch 99 being closed, the vacuum relay 177 will also be energized. The vacuum pump switch 195 is operated by the vacuum relay 177 and is normally in its second position 197. However, when the vacuum relay 177 is energized, the switch 195 is pulled into its first position 193. Since the contact vacuum pump 191 will also be closed because the main coil 169 is energized, in this condition the coil of the solenoid valve 71 is also energized, opening the primary vapor path solenoid 71 to permit flow through the primary vapor path 70 and the common vapor path 90 to the flow path branch point B. As flow proceeds through the primary vapor path 70, the reading on the low side gauge 31 will recede toward a vacuum. When the low side gauge 31 nears 0 psig the, vacuum switch 99 which is set to operate at 4 inches Hg vacuum will open, de-energizing the vacuum relay coil 177 which in turn permits the vacuum control switch 195 to drop into its second position 197, de-energizing the coil of the solenoid valve 71 in the primary vapor path 70 and energizing the coil of the solenoid valve 131 in the secondary vapor path 110. At the same time, if the breaker 199 is closed, power will be available at the vacuum pump power source receptacle, and the vacuum pump 135 will be energized. Thus flow will be discontinued through the primary vapor path 70 and be initiated through the secondary vapor path 130 so that the vacuum pump 135 and the compressor 101 will pull in series together to increase the vacuum applied to the disabled unit. When a deep vacuum has been pulled to the desired level, the power switch 155 can be returned to the OFF condition and all valves closed to complete the evacuation process.
If it is necessary to discontinue operation of the refrigerant recovery unit during the recovery cycle, it may be necessary to wait two or three minutes before restarting the cycle to allow the compressor 101 time to reset. If, after restarting the recover cycle, the compressor 101 does not start, the power switch 155 should be turned off. The second switch 181 should then be turned to the ON or DUMP positions 183 and 185. The coils of the solenoid valves 71 and 105 in the primary vapor path 70 and the common vapor path 90 will then be energized and the pressure will equalize across the compressor 101. It is recommended that the switch 181 be activated to the ON or DUMP positions 183 and 185 before each start so that oil will be returned via the solenoid valve 105 from the oil separator 103 and pressure will be equalized across the compressor 101.
The recovery unit can remain hooked up between the disabled unit and the receiving can until all repairs are completed. At this point all valves will again be opened, except for the discharge valve 153. The valve 143 connecting the port 137 of the vacuum pump 135 to the atmosphere would also be opened. The power switch 155 is then moved to the first and second vacuum positions 165 and 167. In this condition, the compressor 101 is disconnected as is the vacuum relay 177. However, the main coil 169 is energized so that the vacuum pump contact 191 is closed and, since the switch 195 is in its second position 197, the coil of the solenoid valve 131 of the secondary vapor path is energized as is the vacuum pump 135, thus pulling a deep vacuum on the repaired unit. Once again, after the deep vacuum is reached, the power switch 155 is turned to the OFF condition and all valves are again closed.
If it is desirable to evacuate a receiving can, the vacuum pump 135 would be connected to the recovery unit as previously described. The hose can then be connected between the intake valve 17 on the recovery unit and the vapor valve on the receiving can. The safety cord (not shown) would also be connected to the safety switch (not shown) on the receiving can. The conductors 151 and 153 will again be connected to a power source (not shown) and the open-to-atmosphere valve 143 put in the open condition. The intake valve 17 and the vapor valve (not shown) are opened as are all valves on refrigerant hoses. The power switch 155 is then put into the first and second VACUUM positions 165 and 167 and the unit permitted to run until the receiving can reaches a deep vacuum in the range of approximately 29 inches Hg. The power switch 155 is then returned to the OFF positions 163 and 165 and all valves are closed. The hose to the intake valve 17 is disconnected.
If it is further desired to evacuate the recovery unit to zero after completing receiving can evacuation as above outlined, the hose is connected from the receiving can to the discharge valve 53 of the recovery unit. The safety cord is left connected to the receiving can and the power remains connected with the vacuum pump 135 in place. The discharge valve 53 and the discharge valve of the receiving can are then opened, and refrigerant from the high side of the recovery unit will flow into the receiving can. When refrigerant stops flowing, all valves are turned off, and the hose from the discharge valve 53 is disconnected.
To evacuate the recovery unit to 29 inches of Hg., after evacuating the recovery unit to zero, the hose from the receiving can is disconnected. One end of the hose is connected to the intake valve 17 and the other end of the hose to the discharge valve 53. Again, the safety cord is left connected to the receiving can and the power remains connected with the vacuum pump 135 in place. The vacuum-to-atmosphere valve 143 is opened as are the intake valves 17 and the discharge valve 53. The power switch 155 is again turned to the first and second vacuum positions 165 and 167, permitting the vacuum pump to run until the low side gauge 31 indicates that a vacuum in excess of 20 inches Hg. has been reached. The power switch is then turned to the OFF positions 163 and 165, and all valves are closed. All the refrigerant will now be evacuated from the recovery unit which can then be used to evacuate any of a number of refrigerants without contamination.
Thus, it is apparent that there has been provided, in accordance with the invention a refrigerant recovery unit that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments and methods, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.
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A refrigerant recovery unit is provided in which four distinct refrigerant flow paths are automatically controlled by the unit components to perform four separate and distinct functions. In a liquid refrigerant path, liquid refrigerant is recovered from the discharge side of a disabled unit through the refrigerant recovery unit by use of the differential pressure between the disabled unit and the refrigerant receiving can. In a primary vapor path, evacuation of gaseous refrigerant from the high and low sides of the disabled unit is achieved by use of a compressor in the recovery unit which produces a differential pressure to induce flow. This differential pressure is produced solely by the recovery unit compressor until such time as the intake pressure of the compressor reaches approximately 4 inches Hg. vacuum. When the compressor intake pressure reaches 4 inches Hg. vacuum, the system automatically switches to a secondary vapor path for recovering gaseous refrigerant from the high and low side of the disabled unit by sequencing an external vacuum pump in series with the compressor of the recovery unit to produce the differential pressure inducing flow. This differential pressure is continued until the intake pressure reaches a desired vacuum level of up to 29.9 inches Hg. Finally, to recover gaseous refrigerant or non-condensible gas from the high and low side of the disabled unit after the desired vacuum level has been reached, differential pressure is obtained by connecting the external vacuum pump through the recovery unit without using the compressor. This same path can be used to remove non-condensible gas from a receiving can as well.
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CROSS REFERENCES TO RELATED APPLICATIONS
The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/954,892, filed Aug. 9, 2007.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
THE NAMES OR PARTIES TO A JOINT RESEARCH AGREEMENT
Not applicable.
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
Cordless or wireless pad used on a bed to monitor if a person gets or falls out of bed.
2. Discussion of Related Art Including Information Disclosed Under 37 CFR 1.97, 1.98
Residential care facilities, particularly long-term residential care nursing facilities, must provide a considerable measure of protection to residents who may be impaired in their ability to care for themselves or to exercise sound judgment Inherent in such care is the need to routinely confine residents to beds, chairs, or other support apparatus. Accordingly, it is known to provide bed and chair occupancy monitoring systems to alert staff or attendants of inappropriate patient movement.
For example, U.S. Pat. No. 5,410,297 to Joseph teaches a bed monitoring system including a capacitive sensor pad for placement under a patient. The pad comprises a foam plastic pad and heavy aluminum foil plates laminated on opposite sides of the foam. The plates are then adhesively bonded to the inner surfaces of an outer cover. The capacitor of the pad is connected in circuit with an oscillator and produces a frequency-related output. A ripple counter establishes a frequency-related output proportional to the capacitance. A microprocessor reads the counter output and samples are averaged to establish a reference base and the true weight affect of the patient on the sensing pad. Other factors which might effect the signal are readily attended to by programmed compensation. Each subsequent sample is averaged and compared with the reference base. If within a permitted range, the latest and current signal is averaged with the reference base and establishes a new base, and continuously tracks changes in the sensing system. A selected change in a selected time delay system actuates an alert or alarm system, which requires positive resetting to terminate the alarm system. The system is positively reset to return to normal position monitoring. The system may be set to automatically reset the alarm system after an alarm condition is established and then removed by the continuous tracking of the patient movement. Also illustrative of the art, U.S. Pat. No. 5,654,694 to Newham discloses a mobile patient monitoring system. The system includes a load sensor which detects the presence of a patient on a device and further includes a microprocessor responsive to a resident program. A first circuit connected to the microprocessor and to the sensor automatically activates operation of the microprocessor to a “monitor” mode upon detection by the sensor of the patient's presence on the device; it maintains operation of the microprocessor for a predetermined time period at least equal to a running time of the program; and it terminates operation of the microprocessor at the expiration of the predetermined time period after detection by the sensor of termination of the patient's presence on the device prior to expiration of the predetermined time period. A second circuit operates the system in response to commands manually applied to the second circuit to deactivate the system to a “hold/reset” mode after activating of the system to the “monitor” mode. The first circuit will also activate the system to the “monitor” mode after the system has been deactivated to the “hold/reset” mode together with subsequent detection by the sensor of termination of the patient's presence on the device and resumption of the patient's presence on the device. Alternatively, the microprocessor is responsive to the manually operable switch in the second circuit to activate the system to the “monitor” mode after the system has been deactivated to the “hold/reset” mode. A third circuit connected to the microprocessor provides an audio alarm upon demand by the microprocessor.
The present invention provides advantages over prior art systems in that the system sends a wireless signal to a remote monitor. The several advantages of the present invention are set forth below in the summary of the invention.
The foregoing patents reflect the current state of the art of which the present inventors are aware. Reference to, and discussion of, these patents is intended to aid in discharging Applicants' acknowledged duties of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that none of the above-indicated patents disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein.
BRIEF SUMMARY OF THE INVENTION
The present invention is a cordless or wireless pressure pad connected to a bed pad transmitter, which is in wireless communication with a proximate bed monitor. If remote or centralized monitoring is desired, the bed monitor may function as a programmable transmitter unit to relay signals from the bed pad to a central bed monitor receiving and alarm unit.
In use, the pressure pad transmits a single frequency wireless signal or wideband frequency hopping signal to the bed monitor, and if desired, to a central monitor indicating to a caregiver that a patient has gotten out of a bed or fallen out of bed. The wireless signal has a checksum to prevent faulty data, and the wireless link allows the pad to function as if a cord were connecting the pad to the user.
When triggered by the removal of a resident/patient's body weight, the pressure pad transmitter sends a coded signal that is matched with the particular bed monitor or monitors with a “self-read” in operation, and it also sends a signal outside the room directly to a monitor or light in the hall, thereby alerting caregivers to take appropriate action.
In addition, the bed pad transmitter sends a coded “I am okay” signal to the bed monitor receiver, and if the bed monitor receiver misses the pulsed signal over a predetermined and preset period, it will output an alarm signal indicating that the pad is lost or removed. This indicates that the pad has been removed from the area or is no longer working.
Each pad has a uniquely coded chip for matching with the bed monitor, and the pad is matched to the monitor by pressing a read in button on the monitor and then pressing the pad to match the codes automatically.
When a monitored person gets up from the pad the bed pad transmitter will send a signal to the bed monitor unit to trigger an alarm, and when a person sits back down the bed pad transmitter will send a signal to the bed monitor to reset the bed monitor unit.
The bed pad includes a sleeve or pocket into which the uniquely coded bed pad transmitter is inserted, and there plugged into the bed pad using a plug and socket. The pocket is closed using non-removable, tamper proof plastic clips, which must be cut to change the transmitter. The transmitter is waterproof and sealed. The battery power supply lasts more than three years and may be rechargeable.
The signal sent by the bed pad may include other functions to be decided; such as the time to change the pad (i.e., a “change pad indicator”), date manufactured, date first used, and other information to be decided.
Both units (pad and monitor) have a “low battery” circuit which send an alert signal to the bed pad monitor or central monitor. The bed monitor includes an internal wireless receiver to detect the signal from the bed pad transmitter. Alternatively, an intelligent receiver module may be plugged into the bed pad monitor wired pad port or another port as if it were a standard pad. In such a case, the external receiver unit has its own battery, indicator, sounder, and so forth, to allow the features required, such as “pad lost” indication, low battery, and the like. The battery is replaceable. However, the bed monitor receiver can work on battery and/or power supply, and may have a simple LED indicator for a “pad lost” condition with an audible sound and/or a visual output, such as an LCD light or other indicator to show in detail the functions required.
One major advantage of the wireless system of the present invention is that multiple pads can be linked to one bed monitor. This is especially well adapted for use with visual indicators, such as an LCD display. Costs are reduced because only one bed monitor receiver is required, and the alarms may be moved outside the room so as not to disturb the residents while providing a display identifying which bed is in an alarm state. Further, extra data such as pad usable time left/number of activations, and so forth, can be sent from the pad.
Other novel features which are characteristic of the invention, as to organization and method of operation, together with further objects and advantages thereof will be better understood from the following description considered in connection with the accompanying drawings, in which preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration and description only and are not intended as a definition of the limits of the invention. The various features of novelty that characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. The invention does not reside in any one of these features taken alone, but rather in the particular combination of all of its structures for the functions specified.
There has thus been broadly outlined the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form additional subject matter of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based readily may be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIG. 1 is a schematic block diagram showing the functional elements of the cordless bed monitor receiving unit having an LCD display of the present invention;
FIG. 2 is a schematic block diagram of the cordless pad transmitter unit;
FIG. 3 is a schematic block diagram of the plug-in receiver module unit of the present invention;
FIGS. 4A and 4B are schematic block diagrams showing how the transmitter unit is fitted and connected to the patient pad;
FIG. 5 is a schematic block diagram showing pad and monitor systems deployed in a number of rooms, each having dedicated transmitter units for receiving and relaying signals from bed pads to a central monitor;
FIG. 6 similarly shows a multi-pad system, but all bed pad transmitters send signals to a single monitor;
FIG. 7 is a perspective view showing the operative elements of the bed monitor receiver unit with an externally disposed receiver module;
FIG. 8 is a schematic diagram showing a pad and standard receiver pair;
FIG. 9 is a schematic diagram showing a pad and bed monitor with an LCD display;
FIG. 10 is a circuit diagram of the wireless pad transmitter;
FIG. 11 is a circuit diagram of the wireless bed pad receiver unit;
FIG. 12 is a circuit diagram of the bed pad monitor of the present invention; and
FIG. 13 is a circuit diagram of the wireless bad pad monitor having an LCD display.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 through 13 , wherein like reference numerals refer to like components in the various views, there is illustrated therein a new and improved wireless and cordless patient bed pad and monitor system. FIG. 1 is a schematic block diagram showing the functional elements of the cordless bed monitor receiving unit having an LCD display of the present invention, generally denominated 100 herein. It includes a monitor unit portion 110 with an LCD controller 120 , a receiver controller 130 having an autoread button 140 and EEPROM 150 for reading pad transmitter information into memory, and a receiver module 160 , preferably with a multi-frequency hopping option. The receiver further includes a low battery detect circuit 170 , an LCD visual display 180 , an audible output speaker 190 , a switch for controlling inputs 200 , and an LED/relay control/data output circuit portion 210 .
FIG. 2 is a schematic block diagram of the cordless pad transmitter module 300 , preferably including a multi-frequency hopping option, which comprises a microcontroller 310 having a buffer 320 , EEPROM 330 for storing programmed inputs from a keypad or other input device 340 , a low battery detect circuit 350 , and an antenna 360 for transmitting a signal to the receiving unit shown in FIG. 1 .
FIG. 3 is a schematic block diagram of the plug-in receiver module unit 400 of the present invention, which comprises a microcontroller 410 , having a low power receiver module 420 , EEPROM 430 , a low battery detector 440 , an LED indicator 450 with indications for Pad OK, Status, and Low Battery, and an audible output device 460 . Again, the unit includes an autoread button 470 for matching the unit to a bed pad transmitter.
FIGS. 4A and 4B are schematic block diagrams showing how the bed pad transmitter 500 is fitted and connected to the bed pad. The transmitter is connected to the bed pad 510 with a wire connector 520 , and then fitted into a pocket or sleeve 530 , which is closed with a flap 540 and secured with tamper proof clips 550 .
FIG. 5 shows bed pad and bed pad monitor systems 600 , 610 , deployed in a number of rooms 620 , 630 , each system including dedicated transmitter units 640 , 650 , for receiving and relaying signals from bed pads to a central monitor 660 , and an optional LCD display 670 , 680 at each room. The central monitor includes a display 690 showing the room and bed pad monitor 700 , 710 , 720 , 730 that is sending a present signal.
FIG. 6 similarly shows a multi-pad system, but all bed pad transmitters 740 , 750 , 760 , 770 , send signals to a single monitor 780 ;
FIG. 7 is a perspective view showing the operative elements of the bed monitor receiver 800 unit with an externally disposed receiver module 810 . As earlier noted, it will be appreciated that receiver circuitry can be incorporated into the receiver housing or optionally disposed in a plug-in form having a male element 820 for insertion into a female receptacle 830 in the bed monitor receiver housing 840 . The receiver module is battery powered and preferably includes three indicator lights, including low battery 850 , status 860 , and pad lost 870 , as well as a buzzer alarm output 880 .
FIGS. 8 and 9 show pad and receiver pairs, the former with a standard receiver 890 , the latter with an LCD display receiver 900 .
FIG. 10 is a circuit diagram of the wireless pad transmitter 1000 , while FIG. 11 is a circuit diagram 1100 of the wireless bed pad receiver unit. FIG. 12 is a circuit diagram 1200 of the bed pad monitor of the present invention; and FIG. 13 is a circuit diagram 1300 of the wireless bad pad monitor having an LCD display.
Referring to FIG. 10 , there is shown a schematic drawing of wireless pad transmitter 1000 . is connected directly to a bed pad, and transmits the conditions of the bed pad to a proximate wireless bed pad receiver unit 1100 . In this figure, it can be seen that microcontroller U 2 is in communication with connector J 1 , which is externally connected to a bed pad's output port. Through this port, microcontroller U 2 monitors the conditions of the pad. Microcontroller U 2 is programmable via connector J 2 .
DC voltage (VDD) is provided to the circuits of wireless pad transmitter 1000 by way of 3.2 volt battery BT 1 . The output voltage of battery BT 1 is regulated to 3.0 volts by voltage regulator U 3 . VDD is also passed through voltage regulator U 1 , whose output is monitored by the RA 3 analog input on pin 2 of microcontroller U 2 . The software running on microcontroller U 2 generates an alarm when VDD drops below a certain voltage (indicating a low battery condition).
Any alarms generated by microcontroller U 2 are converted into formatted data messages that are then sent (via RB 7 pin 13 of microcontroller U 2 ) to the transmitter module connected to connector J 3 (the data is passed on pin 3 of connector J 3 ). The transmitter module connected to connector J 3 receives these data messages and modulates the data onto the RF signal transmitted to the receiver module connected to a proximate bed pad monitor. In this way, the alarms generated by conditions detected by microcontroller U 2 are sent wirelessly to a remote monitor. Microcontroller U 2 also communicates with memory chip IC 1 . Memory chip IC 1 is used to store data.
Referring now to FIG. 11 , there is shown a schematic drawing of wireless bed pad receiver unit 1100 . Wireless bed pad receiver unit 1100 is connected (via connector J 1 ) to an input port of a non-wireless bed pad monitor, thereby making the monitor operate in a wireless mode. In this schematic, it can be seen that microcontroller U 1 (via RB 7 input pin 13 ) receives data from a RF receiver module via DATA pin 9 of connector J 2 . This is the path by which data transmitted by wireless pad transmitter(s) 1000 is passed to microcontroller U 1 .
Note that, through the receiver, microcontroller U 1 can receive data from more than one wireless pad transmitter 1000 . However, only data from those wireless pad transmitters that have been ‘matched’ to the specific instance of wireless bed pad receiver unit 1100 will be processed.
To ‘match’ a specific wireless pad transmitter 1000 to the specific instance of wireless bed pad receiver unit 1100 , the user first presses ‘LEARN MODE’ momentary-on switch SW 2 . This causes RA 3 pin 2 on microcontroller U 1 to be pulled up from ground to VDD. The software running on microcontroller U 1 detects this change, and begins running ‘learn mode’ routines that store (in memory chip IC 1 ) data captured by the receiver module connected to connector J 2 . Microcontroller U 1 then automatically ‘matches’ to (stores the unique transmitted code of) any wireless pad transmitter 1000 that is transmitting nearby. While wireless bed pad receiver unit 1100 is in this mode, one or more wireless pad transmitter 1000 can be triggered (by pressing on the pad itself) to transmit, and thereby be ‘matched’ to the specific instance of wireless bed pad receiver unit 1100 . Wireless bed pad receiver unit 1100 is can be made to exit the learning mode by pressing ‘LEARN MODE’ momentary-on switch SW 2 once again.
In FIG. 11 it can also be seen that wireless bed pad receiver unit 1100 receives +5V DC voltage (VDD) via pin 1 of connector J 1 . Connector J 1 is externally connected to a monitor that analyzes and displays to received information to a user. VDD is regulated by voltage regulator U 5 and then passed to the receiver module via transistor Q 2 , and then through pins 6 and 10 of connector J 2 . Transistor Q 2 can be turned on and off by microcontroller U 1 (via RB 6 pin 12 of microcontroller U 1 ). Turning off transistor Q 2 causes the VDD to be removed from the receiver module.
Still referring to FIG. 11 , it can be seen that microcontroller U 1 passes information to the monitor attached to connector J 1 . The information provided to the monitor includes: on pin 2 of connector J 1 , a ‘buzzer-on’ condition, on pin 3 of connector J 1 , a ‘RF signal lost’ condition, on pin 4 of connector J 1 , a ‘RF signal OK’ condition, on pin 5 of connector J 1 , a ‘bed pad’ condition, on pin 6 of connector J 1 , a ‘mat’ condition, on pin 7 of connector J 1 , a ‘low battery’ condition.
Now referring to FIG. 12 , a circuit diagram of wireless bed pad monitor 1200 is shown. It can be seen that wireless bed pad monitor 1200 is a bed monitor circuit integrated with the key elements of a bed pad receiver unit 1100 . First, addressing the receiver portion of the schematic of FIG. 12 , it can be seen that microcontroller U 3 (via RB 7 input pin 13 ) receives data from a RF receiver module via DATA pin 9 of connector J 5 . This is the path by which data transmitted by wireless pad transmitter(s) 1000 is/are passed to microcontroller U 3 . Note that, through the receiver, microcontroller U 3 can receive data from more than one wireless pad transmitter 1000 . However, only data from those wireless pad transmitters that have been ‘matched’ to the specific instance of wireless bed pad receiver unit 1100 will be processed.
To ‘match’ a specific wireless pad transmitter 1000 to the specific instance of wireless bed pad monitor 1200 , the user first presses ‘LEARN MODE’ momentary-on switch S 1 . This causes RA 3 pin 2 on microcontroller U 3 to be pulled up from ground to VDD. The software running on microcontroller U 3 detects this change, and begins running ‘learn mode’ routines that store (in memory chip IC 1 ) data captured by the receiver module connected to connector J 5 . Microcontroller U 3 then automatically ‘matches’ to (stores the unique transmitted code of) any wireless pad transmitter 1000 that is transmitting nearby. While wireless bed pad monitor 1200 is in this mode, one or more wireless pad transmitter 1000 can be triggered (by pressing on the pad itself) to transmit, and thereby be ‘matched’ to the specific instance of wireless bed pad monitor 1200 . Wireless bed pad monitor 1200 is can be made to exit the learning mode by pressing ‘LEARN MODE’ momentary-on switch S 1 once again.
In FIG. 12 it can also be seen that wireless bed pad monitor 1200 receives +5V DC voltage (VDD) from the output of voltage regulator U 4 . VDD is regulated by voltage regulator U 5 , and then passed to the receiver module via transistor Q 4 , and then through pins 6 and 10 of connector J 2 . Transistor Q 4 can be turned on and off by microcontroller U 3 (via RB 6 pin 12 of microcontroller U 3 ). Turning off transistor Q 4 causes the VDD to be removed from the receiver module.
Still referring to FIG. 12 , it can be seen that microcontroller U 3 (via RA 2 pin 1 of microcontroller U 3 ) passes data to microcontroller U 2 (via RA 3 pin 2 of microcontroller U 3 ). In this way microcontroller U 2 receives bed pad alarm information that has been received by the receiver unit.
Microcontroller U 3 performs the function of illuminating the Signal Lost LED 4 and Signal OK LED 3 based on the conditions of the radio frequency signals currently being seen by the receiver module attached to connector J 5 . Microcontroller U 3 (via RB 3 pin 9 of microcontroller U 3 ) also controls the current flow through transistor Q 2 . Turning the current on through transistor Q 2 activates buzzer BUZ 1 . Turning off the current through transistor Q 2 deactivates buzzer BUZ 1 .
Microcontroller U 3 (via RA 0 pin 17 of microcontroller U 3 ) outputs a MAT logical signal that indicates the condition of an attached mat (if a mat is attached). This MAT logical signal is passed to pin 4 of telephone jack connector J 1 . This MAT logical signal is also passed to RB 0 pin 6 of microcontroller U 3 . In this manner, any conditions detected in data received by microcontroller U 3 (from the receiver module connected to connector J 5 ) are made available to both microcontroller U 2 and to a wireless pad transmitter 1000 connected to wireless bed pad monitor 1200 via telephone jack connector J 1 . If a wireless pad transmitter 1000 is connected to wireless bed pad monitor 1200 via telephone jack connector J 1 , then the integrated system acts as a repeater, receiving transmitted messages from instances of wireless pad transmitter 1000 , and then wirelessly transmitting those messages to a remote centralized wireless monitoring system. This approach is used when placing an instance of positioning a wireless bed pad monitor 1200 just over the door of each room on a nursing floor in a hospital. In this scenario, a centralized wireless monitor system is positioned at the nursing station. As a bed pad alarm is generated, the wireless bed pad monitor 1200 just over the door of the room in which that bed pad resides will display an alarm locally, and then re-transmit the message to the centralized monitor at the nurse station. In this way, the nurse at the station can see the alarm, and then proceed to deal with the issue immediately. Also, if a nurse is not at the nurse station, then the visible and audible alarm generated locally by wireless bed pad monitor 1200 will immediately guide the nurse to the bed from which the alarm was issued.
Still referring to FIG. 12 , the functions of microcontroller U 2 and its associated circuits are now described. It can be seen that DC voltage is provided to the module in one of two ways. First, battery power is provided to voltage regulator U 4 via battery connector J 6 and diode D 6 . Voltage regulator U 4 provides +5V VDD as its output. The second power input is +9VDC or 9VAC from an external source via 9 mm power jack J 4 . This voltage is fed through bridge rectifier D 2 (BRIDGE 1 ) to the Vp source point, as well as to the input of voltage regulator U 4 via diode D 5 . The input (pin 2 ) of voltage regulator U 4 is also the source point for VA. VA serves as the voltage by which the battery condition is measured.
The battery condition is determined by having VA feed the input of voltage regulator U 1 , the output of which (when the unit is operating only on battery) provides the only voltage to input RA 1 pin 18 of microcontroller U 2 . The software running on microcontroller U 2 measures the regulated VA voltage and determines the battery condition based on this voltage. If the voltage drops below a predetermined value, then the software running on microcontroller U 2 generates an alarm. It can be seen that microcontroller U 2 can illuminate alarm indicators LED 1 and LED 2 . It can also be seen that microcontroller U 2 can generate an oscillating signal out through transistor Q 1 and inductor L 1 to connector J 2 . The output level of this signal is adjusted by way of variable resistor VR 1 . It can further be seen that microcontroller U 2 can (via RB 7 output pin 13 of microcontroller U 2 ) operate the dry contacts of SPDT relay K 1 via control of transistor Q 3 (transistor Q 3 activates and deactivates relay K 1 . Relay K 1 provides a dry contact output for external systems use. This output can be either polarity, depending on which pins of connector J 3 are used. The outputs described above are operated under the control of the software running on microcontroller U 2 . This software also regularly examines the condition of momentary-on reset button SW 2 , as well as the condition of magnetic switch SW 3 via RA 0 input pin 17 of microcontroller U 2 . If magnetic switch SW 3 closes, the software interprets this as a reset command, and as long as switch SW 3 remains closed, no action is taken. If reset button SW 2 is pressed (and reset on//off switch SW 1 is set to ‘ON’) the software interprets this as a reset, and clears its alarms.
Additionally, the software running on microcontroller U 2 monitors the condition of inputs RB 1 (pin 7 ), RB 2 (pin 8 ) and RB 3 (pin 9 ) to determine the tone setting established by the position of tone selector switch SW 4 .
Now referring to FIG. 13 , a circuit diagram of (a non-wireless) bed pad monitor 1300 with an LCD display is shown. It can be seen that bed pad monitor 1300 received bed pad conditions through telephone jack connector J 1 (which is connected directly to the output port of a bed pad). The microcontroller U 2 receives the inputs present on connector J 1 as pad condition (at RA 2 pin 8 of microcontroller U 2 , mat condition (at RB 0 pin 10 of microcontroller U 2 and other condition (at RC 1 pin 19 of microcontroller U 2 ). In this arrangement, microcontroller U 2 can detect and analyze each of these conditions.
Microcontroller U 2 also regularly monitors the condition of momentary-on delay switch SW 3 . If this button is pressed, microcontroller U 2 ignores external inputs for a period of time, and therefore, during that time, will not generate alarms. Microcontroller U 2 also regularly monitors the condition of momentary-on switch SW 3 .
Still referring to FIG. 13 , it can be seen that microcontroller U 2 controls the displayed image of the LCD display by shifting data serially into logic translator U 14 . Logic translator U 14 then translates the serial input into a parallel output to the LCD display. In this way, microcontroller U 2 can display messages on the LCD display. Microcontroller U 2 can also operate buzzer U 4 and alarm LED D 8 .
In addition to the LCD display, microcontroller U 2 controls other outputs, including dry contact relay K 1 . In the configuration shown in FIG. 13 , microcontroller U 2 detects (via telephone jack connector J 1 ) the locally connected bed pad's conditions, and then displays those conditions on the LCD display, as well as providing audible and visible alarm indications.
The above disclosure is sufficient to enable one of ordinary skill in the art to practice the invention, and provides the best mode of practicing the invention presently contemplated by the inventor. While there is provided herein a full and complete disclosure of the preferred embodiments of this invention, it is not desired to limit the invention to the exact construction, dimensional relationships, and operation shown and described. Various modifications, alternative constructions, changes and equivalents will readily occur to those skilled in the art and may be employed, as suitable, without departing from the true spirit and scope of the invention. Such changes might involve alternative materials, components, structural arrangements, sizes, shapes, forms, functions, operational features or the like.
Therefore, the above description and illustrations should not be construed as limiting the scope of the invention, which is defined by the appended claims.
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A cordless pressure pad connected to a bed pad transmitter for centralized monitoring by a central bed monitor receiving and alarm unit. When a monitored person gets up from bed, the pad transmitter sends a coded RF signal matched to a particular bed monitor unit, and it then triggers an alarm; when the person sits or lays back down, the pad transmitter sends a signal to the monitor to reset. Multiple pads can be linked to a single bed monitor.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 61/132,376, filed Jun. 18, 2008, which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to sound reproduction systems in which one or more drivers, mutually coupled to a horn member, have their amplitude distribution altered by vanes disposed in the interior of the horn member.
DESCRIPTION OF THE RELATED ART
Originally, the art of horn loading of point source drivers was done to increase the electroacoustic efficiency of the drivers. Various techniques were employed early on to make the most of limited amplifier power and relatively low power handling capabilities of available drivers. Early efforts were centered around obtaining the greatest sound level possible. Horn loaded speakers, sometimes referred to simply as “horns” or “warning systems” of this early era were generally designed to have a specific expansion rate throughout, and typically were made to have a defined shape such as that of a simple cone as well as curved wall flares having shapes corresponding to exponential or hyperbolic curves. Typically, these designs were aimed at giving the best low-frequency performance.
Complementary horn/driver systems were developed for different frequency ranges to optimize the ability of a horn to confine the sound wave in a practical manner. The design of relatively low frequency horns encountered challenging problems because of the mass and acoustic size required, and because the ability of a horn to confine the sound to a given angle diminishes below some frequency defined by the wavelength being produced for horns having a practical wall angle and dimension. For practical horns, a frequency inevitably arises where, due to practical dimensional considerations, the horn loses the ability to control the radiation angle of the soundwave being guided by the enclosure.
As noted above, one practical challenge faced by loudspeaker systems of all types is the ability to deliver a minimum desired sound pressure level to the listener's environment. Over the years, certain fundamental types of loudspeaker systems have been recognized for their inherent ability to deliver sound pressure levels. The two most popular types are those employing point source drivers (cones, domes, horns, multicellular panels, etc.). and line source drivers (e.g. ribbon drivers and elongated planar drivers). With point source drivers, sound is conceptualized as emanating from a single point, expanding in all directions, i.e. “spherically” (e.g. vertically, floor to ceiling and horizontally, side to side).
In contrast, a line source radiates sound in a cylindrical pattern. Sound travels outward from the driver in the shape of an expanding cylinder, bounded at its ends by flat end planes, and not as an expanding sphere, as in the case of point sources. This confined soundwave pattern of a line source is inherently more efficient that that of a point source, since the expanding spherical sound energy of a point source is confined into the shape of an expanding cylinder, so as to “focus” or concentrate the same energy into a spatial region of reduced size. Theoretically, line source systems are twice as efficient as point source systems.
Line sources may be characterized as a type of acoustic source which is acoustically large in one dimension (their length) but acoustically small in the other direction (cross-sectional dimension). Attempts have been made, for example, to emulate a line source by a linear arrangement of discrete line sources. Despite some interesting results, improved systems are still being sought. One problem with such arrangements, for example, is the undesirable interaction of one point source with another that inevitably arises due to propagation effects arising in a practical system.
Attempts have been made over the years to improve speaker systems used to deliver sound to large audiences. Outdoor locations have proved particularly difficult for sound engineers, with nonlinearities in frequency response and amplitude distribution posing the greatest challenges.
SUMMARY OF THE INVENTION
The present invention provides a novel and improved sound reproduction system in which the physical soundwave paths from a driver to the system output is made to be different at different locations, so as to shape the amplitude distribution of the system soundwave output.
In one embodiment, this is accomplished with the use of dividers or vanes within a horn system. The positions of the vanes and their interaction with the soundwave alter the normal amplitude distribution that a similar horn system without vanes would produce. By introducing zones of reduced pressure rather than a physical boundary, more directivity can be achieved than would otherwise be expected.
One embodiment of a sound reproduction system according to principles of the present invention includes a system for reproducing sound, comprising at least one driver and a horn member in acoustic loading relationship to the driver. The horn member defines an internal passageway having a first end and a second open end, with the at least one driver at the first end, producing a driver soundwave having an initial central axis and an initial amplitude distribution. A plurality of vanes are disposed in the internal passageway, at different angles from the central axis and deflect respective portions of the driver soundwave so as to alter the initial amplitude distribution.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings,
FIG. 1 is a diagrammatic representation of a first embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 2 is a schematic diagram of a radiation pattern for the first embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 3 is a diagrammatic representation of a second embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 4 is a schematic diagram of a radiation pattern for the second embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 5 is a diagrammatic representation of a third embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 6 is a schematic diagram of a radiation pattern for the third embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 7 is a diagrammatic representation of a component of a fourth embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 8 is a diagrammatic representation of the fourth embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 9 is a diagrammatic representation of a fifth embodiment of a sound reproduction system illustrating certain aspects of the present invention;
FIG. 10 is a perspective view of a flying sound reproduction system illustrating certain aspects of the present invention;
FIG. 11 is a perspective view showing interior details of the flying sound reproduction system illustrating certain aspects of the present invention;
FIG. 12 is a perspective view showing further interior details of the flying sound reproduction system illustrating certain aspects of the present invention;
FIG. 13 is a rear perspective view showing drivers employed with the flying sound reproduction system illustrating certain aspects of the present invention;
FIGS. 14 and 15 are schematic diagrams illustrating design features addressing certain aspects of the present invention;
FIG. 16 is a schematic diagram of an outdoor location with a flying sound reproduction system;
FIGS. 17 a - 17 o are schematic diagrams showing performance of a sound reproduction array according to the present invention, taken at different distances from the system; and
FIGS. 18 a - 18 g show the sound reproduction array in greater detail.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention disclosed herein is, of course, susceptible of embodiment in many different forms. Shown in the drawings and described herein below in detail are the preferred embodiments of the invention. It is to be understood, however, that the present disclosure is an exemplification of the principles of the invention and does not limit the invention to the illustrated embodiments.
For ease of description, sound reproduction systems embodying the present invention are described herein below in their usual assembled position as shown in the accompanying drawings and terms such as front, rear, upper, lower, horizontal, longitudinal, etc., may be used herein with reference to this usual position. However, the sound reproduction systems may be manufactured, transported, sold, or used in orientations other than that described and shown herein.
The present invention addresses problems that sound engineers have had to deal with time and again. With reference to FIG. 16 , a typical outdoor application for a sound reinforcement speaker 10 is shown. Speaker 10 operates as a point source suspended above an audience seating area 12 . Three path lengths of the speaker soundwave output are shown. It is clear that, due to the inverse square law that governs operation of point sources, that the delivered soundwave is louder in the front rows than the back rows. As will be seen, the present invention overcomes this falling sound pressure level with increasing distance.
“Line source” speaker systems have become popular in sound reinforcement applications. While these types of systems tend to be vertical rows of drivers (see, for example, U.S. Pat. No. 6,834,113) and not actually a homogenous source, systems are available that do function reasonably well as a true line source. One example of a real line source, embodied as a full length ribbon driver, is the Radia Pro 1.9 ribbon line array, commercially available from BG Corp., 3535 Arrowhead Dr., Carson City, Nev. 89706 USA.
Theoretically, when a planar acoustic source, such as a vertical ribbon speaker, is many wavelengths long, the shape and acoustic size confine the radiation to a very small angle in the vertical plane. If the line source is large enough acoustically, what is radiated by the “line source” is a cylindrical shaped wavefront (spreading in one plane only) instead of a spherical one. One advantage of this is that, when one confines the radiation angle to zero degrees or “no spreading” in one axis, then the sound pressure level fall-off with respect to distance, is theoretically half that of the point source. This means, for example, that instead of the level falling 6 dB per doubling of distance, it only falls 3 dB.
In commercial sound engineering applications, this advantage in theory means that the back row of the audience will have a sound level that is greater than they would have experienced from a point source system having the same “front row” sound pressure level. In this use (see FIG. 16 ), the line source replacing the point source would be oriented vertically (i.e. becoming a vertical line source), confining the outputted soundwave pattern in a vertical plane.
One downside of the line source system is that the effect depends entirely on the “acoustic size” of the source (i.e. the driver). In practice, what are called “line sources” typically act like point sources at low frequencies as they are acoustically too small, act line a line source only part of the time in the mid range of the output frequency regime, while at high frequencies, the individual sources act like individual point sources (with attendant overlapping interference regions) instead of combining into an acoustic line source.
One finds that this type of “line source” system has a highly variable spectrum or frequency response as a function of distance from the system. As a result, the distribution of high, mid and low frequencies changes, depending on how far away from the source the listener is located, and at any given point in the audience area, a high resolution measurement will reveal peaks and dips related to the line length. This result arises because a given length line array exhibits, in effect, a variable acoustic length, the dimensions of which are fixed while the wavelength varies in size.
Wavelength can be found by taking the speed of sound, divided by the frequency. For example, 1132 Feet per second/100 Hz=a wavelength of 11.32 feet, or 135.8 inches, while the wavelength at 10 Khz is then 1.35 inches etc. The variability of the line sources angular radiation as a function of frequency has been observed. To compensate for this problem, line source systems are generally curved physically or in time, electronically, to try to partially emulate a point source, reducing the frequency dependent line effect. In the case of an acoustically tall source, it's physical size produces a variable vertical radiation pattern, narrowing as the frequency climbs, an effect that is caused by the source having a length of increasing number of wavelengths in dimension.
Many systems erroneously described as “line array” systems in use have the additional problem in that they are a large number of individual sources which are acoustically too far apart to combine into a homogonous source. These and other acoustic problems related to sources that attempt to emulate true line sources is why customary frequency response curves used throughout the industry for other types of devices are oftentimes no longer used for these types of systems.
Referring again to FIG. 16 a speaker 10 is flown in the air in front of an audience 12 seated in an outdoor venue. Since speaker 10 operates as a point source, the sound pressure level of its output soundwave falls off by 6 dB each time the distance to the source is doubled. As a result, the rear seats would receive considerably less (about 1/100) than the sound level delivered to the front rows. Assuming, for example, the speaker 10 operates as a constant directivity point source and unlike the line array, its response or sound spectrum does not depend on or change significantly with distance from the source, only the sound level changes with distance. If the speaker were replaced by a line source whose vertical directivity changes a great deal throughout the “full range of music, the amplitude changes less with distance but now the spectrum or the speaker frequency response changes also with distance.
Attempts have been made in the past, but before the popularity of line arrays, to try to deal with the inverse square law. One method employed the use of a cluster of point source horns, using a “long throw” (physically large, narrow angle coverage) horn pointed to the last row, with a smaller, wider coverage angle speaker below and so on. While conceptually this “long/medium/short” throw horn approach appeared promising, problems arose because actual practical sources do not actually add together coherently, but rather interfere with each other, so much so, that the development of the line source essentially made this approach obsolete. At this point in time, little was known about what was needed to make drivers covering different ranges combine coherently. These earlier solutions resulted in individual horns that, at best, could only cover a narrow frequency range.
By way of a different approach, the present invention alters the directivity and amplitude distribution of a horn which allows shading, compensation or selective favoring of the amplitude, in a particular direction. One embodiment of the present invention employs a shaded amplitude lens to be added in combination with a conventional horn system, including horn systems driven by point source or line source drivers. As a result, a single horn can be produced with an output or radiated sound pattern that performs like previous assemblies comprised of “perfect” long, medium and short throw horn sections. In contrast, with the present invention, the system can include but a single horn whose output is shaded or skewed so as to favorably alter the amplitude distribution of the system. Systems according to principles of the present invention can be employed alone, or a one or more stages of a larger system.
When a horn mouth is acoustically large enough relative to the wavelength being produced, the horn wall angle defines the edge (−6 dB point) of the horn's radiation pattern. One explanation for this “confining effect” is found in a paper by Don Keele entitled “What's So Sacred About Exponential Horns?”, 51st AES convention preprint, page 1038. In this paper, a formula is given for the relationship between the acoustic dimension and the wall angle, which governs directivity at a given point in a horn system.
A horn with straight sides has radiation patterns that are essentially constant down to the frequency where the mouth dimension and angle control intercept point is reached. With a practical horn system, there is a solid physical boundary which confines sound. According to one embodiment of the present invention referred to as a “shaded amplitude lens,” dividers or vanes are employed within the horn enclosure. The positions of the vanes alter the normal amplitude distribution that a similar horn without vanes would produce. By avoiding the use of a solid physical boundary, in favor of zones of reduced pressure, more directivity can be achieved than would be expected were conventional approaches applied to solve the problem.
Referring now to FIGS. 1-4 , a simple conical horn system 16 shown in FIG. 3 has a radiation pattern as shown in FIG. 4 . The horn system 16 includes a driver 18 and a simple conical horn enclosure or sound barrier 20 that presents an acoustical load to the driver output. FIG. 1 shows the horn system fitted with an appropriate shaded amplitude lens 26 to produce an improved sound system generally indicated at 30 . The improved radiation pattern of system 30 is shown in FIG. 2 , for comparison with the radiation pattern of the unimproved system 16 shown in FIG. 4 . Notice that, with the present invention, the output, radiated energy is confined more to the central angle and less is present near the pattern edges.
With reference to FIG. 7 , alteration by the present invention of the radiation angle and amplitude is considered with reference to a planar source of sound, such as a ribbon speaker 36 or other source which is homogenous top to bottom, and that is attached to a simple conical horn 38 . A source of this type would not normally be suitable for driving a horn in the length plane. However, by adding the shaded amplitude lens 40 of the present invention as shown in FIG. 5 , one can alter the normal sized governed radiation angle over a wide frequency range into a more or less constant angle, very much unlike the source alone. The radiation pattern for the improved system of FIG. 5 is shown in FIG. 6 . In addition, the sound energy can be focused or aimed within the outer horn wall angles. In this example, the source also has constant amplitude over its entire area, allowing the source to be broken up into sections, with the desired proportional power based on the fraction of the total area treated. For example, assuming it is desirable to confine half of the total energy into the center of coverage, the improved horn can be made to have a narrower pattern (in the normal direction), making it deeper and narrower, thereby also raising the frequency where pattern control is lost.
FIG. 5 shows lens 40 with its component vanes 42 added to define a custom radiation angle and amplitude distribution. In this example, the center section has vanes that are set at a + and −5 degrees relative to the center. In this case, each set of vanes are 5 degrees greater angle than before, until reaching the outer horn walls 38 , drawn as a 60 degree horn. Note the length or area which is driven at the input end of each 5 degree section and that the next larger angle section has half the area at the driver and so gets driven with half the acoustic power. Here, the amplitude shading drops a fixed rate of 3 dB per 5 degrees.
The amplitude for each section is “shaded” or reduced by some ratio or other relationship, by adjusting the percentage of the total of each section by adjusting the area at the small end. From that, one sees that for one cell to be −3 dB from another, it has to have half the area (in the condition here where the source pressure is constant). It should be noted that neither a planar or a constant amplitude source are required to practice the present invention, but these types of drivers make the design and explanation easier.
While losses of 3 dB (a factor of two) are mentioned in the course of describing the present invention, the reduction in amplitude for adjacent cells has been as large as 6 dB in some prototypes constructed according to principles of the present invention, and as small as 1 dB in others. In each case, the amplitude is distributed by the ratio of areas at the small end of the vanes.
While the division of the amplitudes can be accomplished by the area shading, the effect of the lens is that of altering the progress of the wavefront by the physical path lengths being different at different locations. FIG. 8 shows the improved system of FIG. 5 , from the standpoint of the wavefront or time. Dotted reference lines 46 , labeled a-f, show several identical length paths and the dashed reference line 50 is the custom wavefront shape that results.
Notice that, due to its large acoustic size, the flat planar line source 36 would normally have very narrow, length-governed radiation angle in this plane. With the introduction of the shaded amplitude lens, the total radiation angle is expanded to 60 degrees with approximately half the energy concentrated into a 10 degree angle. As demonstrated here, the shaded amplitude lens can both alter the wavefront shape for directivity purposes and alter the distribution of energy within the horn outer wall angle.
Using the present invention, for example, one could also construct a lens for a source that is acoustically large in both planes like an acoustically large, flat piston. In the examples illustrated herein, however, the horn walls in the horizontal plane define the radiation angle.
The present invention allows one to address the inverse square law problem by directing an increasing portion of the total energy to the most distant locations, to partly or fully compensate for falloff according to the inverse square law. With the present invention, the different distances from the source to the audience members and the inverse square law is taken into account.
While the foregoing examples employ systems that are symmetric about the center line, the present invention may also be employed to produce an asymmetric lens for use in asymmetric systems. Referring now to FIG. 9 an asymmetric distribution lens 56 on the planar source 36 . Notice that half of the energy is confined from zero degrees to 10 degrees down angle and then each 10 degree angle section is −3 dB or half the area. If desired, −6 dB steps could be employed instead, with each step one fourth the area. A −10 dB step would be one tenth, a −12 dB step would be one sixteenth, and a −20 dB step would be one one-hundredth and so on. It should be noted that the amplitude shading produces a highly asymmetric radiation pattern. This source can be substituted for source 10 in FIG. 16 to provide a constant loudness contour radiation pattern from an appropriate shaded amplitude lens. Notice that one side of the radiation pattern can be tailored to offset the inverse square law to the audience. In this drawing, essentially everyone would be hearing the same loudness and because it is a point source, the frequency response is essentially the same at each seat.
FIG. 10 shows a product in which two improved systems are located side by side. FIG. 11 shows a close up view of one of the improved systems, and FIG. 12 shows the same improved system, looking into the horn with the vanes removed for clarity of illustration. FIG. 13 shows the rear of the improved system, exposing an arrangement of drivers. The mid range drivers are coupled into the section before the vanes begin and the low frequency (longer wave length) driver pressure is added through holes into the vane cells. FIGS. 18 a - 18 g show a flying sound reproduction system employing three of the systems of FIGS. 10-13 . FIG. 18 a shows a front view with three speaker enclosures arranged in a triangular array as can be seen in the top plan view of FIG. 18 e . FIG. 18 b is a cross-sectional view taken along a vertical mid-section of FIG. 18 a . FIG. 18 c shows a front view of the array with the outer shell removed. FIG. 18 d shows a rear elevational view of the array. The top plan view of FIG. 18 e shows three of the enclosures arrayed to cover an audience from an elevated or flying position. FIG. 18 f is a vertical cross-section of the array. FIG. 18 g is a perspective view of one of the enclosures, shown partly broken away, so as to expose the vanes disposed within the enclosure. FIGS. 17 a - 17 o show measured performance of loudness and frequency response of the array, taken at a number of different distances. Notice how the spectrum and amplitude change very little over the large range of distances at which measurements were taken.
A brief discussion of governing conditions related to the present invention will now be considered. A horn directing a source's radiation pattern is an example of sound propagating in a duct in an acoustically large condition. Here, directivity is controlled by the horn passageway which is normally larger across than the wavelength being produced. On the other hand, when sound is traveling in an acoustically small condition (through a duct which is very small compared to the wavelength), it has no directivity and is able to go around corners without a problem like a simple pressure system.
With the shaded amplitude lens there are two similar rules of thumb. The angle of the vane requires that the sound bend to accommodate a new angle. An important condition that should be observed, allows the sound to actually bend as desired. This condition defines the frequency point below which the passage way dimensions and bend angle have essentially no adverse effect. This would apply to conventional parallel plate lenses. FIG. 14 shows a planar wavefront entering one cell of a lens. In order for the wavefront to change direction and propagate perpendicular to the centerline, the difference in path lengths “A” where the angle changes must be less than ⅓ wavelength at the highest frequency of interest. Dimensions greater than that allow internal cancellation and ripples in the response as well as the possibility of propagating higher order modes (sound bouncing from wall to wall within a cell). FIG. 15 shows the exits of two adjacent cells where a second acoustic size rule should be followed. The difference between two adjacent cells where the radiations join can be no more than ⅓ wavelength as shown, at the highest frequency of interest.
The foregoing description and the accompanying drawings are illustrative of the present invention. Still other variations in arrangements of parts are possible without departing from the spirit and scope of this invention.
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A sound reproduction system is disclosed in which at least one driver is provided, along with a horn member in acoustic loading relationship to the driver. The horn member defines an internal passageway having a first end and a second open end, with the driver at the first end, producing a driver soundwave having an initial central axis and an initial amplitude distribution. A plurality of vanes are disposed in the internal passageway, at different angles from the central axis to deflect respective portions of the driver soundwave so as to alter the initial amplitude distribution.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a wrench with character units that form an anti-slipping section.
[0003] 2. Description of the Related Art
[0004] Typical wrenches include a smooth handle with anti-rusting treatment. However, these wrenches cannot provide anti-slipping effect at the handles. Taiwan Utility Model Publication No. 530724 discloses a wrench having a handle with an indentation section with embossed or debossed characters. However, no anti-slipping effect is provided, for the characters are located in a central area of the handle. As a result, the user's hand is liable to slip while using the wrench, as it is not uncommon that the user's hand has oil and dust.
[0005] Taiwan Utility Model No. M294392 discloses wrenches including handles with various pressed patterns. The pressed pattern of each handle is located around a trademark on the handle. However, the pressed pattern providing a background of the trademark is too complicated and, thus, obscures the trademark, failing to obtain the desired advertising effect.
SUMMARY OF THE INVENTION
[0006] A wrench in accordance with the present invention includes a body having two ends and a handle between the ends of the body. At least one of the ends of the body is adapted for driving an object. A plurality of character units are provided on each holding face and form an anti-slipping section. At least one of the holding faces includes at least one indication area located in the anti-slipping section. The indication area includes an indication marking. The character units provide a prominent characterizing effect in addition to anti-slipping effect.
[0007] The character units may be embossed or debossed.
[0008] The character units may be regularly arranged to provide an anti-slipping effect in a desired direction or irregularly arranged to provide an anti-slipping effect in all directions.
[0009] Preferably, each character unit includes trademark, figures, characters, marks, symbols, trade name, or combination thereof.
[0010] Preferably, the indication marking includes a size of the wrench, trademark, figures, characters, marks, symbols, trade name, or combination thereof.
[0011] Preferably, the indication marking is the same as but larger than each character unit.
[0012] Preferably, the indication marking has a length two to four times of that of each character unit and a width two to four times of that of each character unit, providing the required prominent characterizing effect.
[0013] In an example, the at least one indication area is surrounded by the character units.
[0014] In another example, the indication marking is spaced from the character units.
[0015] In a further example, the character units extend into the at least one indication area and overlap with the indication marking.
[0016] In still another example, at least some of the character units overlap with each other.
[0017] Preferably, the holding faces of the wrench respectively correspond to upper and lower horizontal faces of the ends of the wrench and the lateral faces of the wrench correspond to outer circumferential faces of the ends of the wrench.
[0018] Other objectives, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a top view of an example of a wrench in accordance with the present invention.
[0020] FIG. 2 is a top view illustrating another example of the wrench in accordance with the present invention.
[0021] FIG. 3 is a top view illustrating a further example of the wrench in accordance with the present invention.
[0022] FIG. 4 is a top view illustrating still another example of the wrench in accordance with the present invention.
[0023] FIG. 5 is a top view illustrating yet another example of the wrench in accordance with the present invention.
[0024] FIG. 6 is a top view illustrating still another example of the wrench in accordance with the present invention.
[0025] FIG. 7 is a top view illustrating yet another example of the wrench in accordance with the present invention.
[0026] FIG. 8 is a top view illustrating still another example of the wrench in accordance with the present invention.
[0027] FIG. 9 is a top view illustrating yet another example of the wrench in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] Referring to FIG. 1 , an example of a wrench in accordance with the present invention comprises a handle 10 having two ends 11 . Each end 11 of the handle 10 includes a driving section or diving member 111 for driving a fastener, a socket, an adaptor, etc. In the example shown in FIG. 1 , the handle 10 includes an open end and a box end. In another example shown in FIG. 2 , the handle 10 includes two open ends. In a further example shown in FIG. 3 , the handle 10 includes two box ends.
[0029] The handle 10 includes two opposite holding faces 101 and two opposite lateral faces 102 extending between the holding faces 101 . Each holding face 101 has a width greater than that of each lateral face 102 . In this example, the holding faces 101 respectively correspond to upper and lower horizontal faces of the ends 11 of the wrench whereas the lateral faces 102 correspond to outer circumferential faces of the ends 11 of the wrench.
[0030] A plurality of character units 131 are provided on each holding face 101 and form an anti-slipping section 13 for providing the handle 10 with friction. The character units 131 may be embossed or debossed to provide the required anti-slipping effect. Further, the character units 131 may be arranged in a matrix. Alternatively, the character units 131 may be aligned crosswise or slantwise to provide desired anti-slipping effect in desired directions.
[0031] Each character unit 131 may be meaningful words such as English characters or trademark. Alternatively, each character unit 131 may include figures, characters, marks, symbols, trade name, or combination thereof. The character units 131 provide a prominent characterizing effect in addition to the anti-slipping function. The customers will be impressed and the desire of purchase will rise in the customers' minds.
[0032] Each holding face 101 of the handle 10 may further include an indication area 14 in the anti-slipping section 13 . In this example, the indication area 14 is surrounded by the anti-slipping section 13 . The indication area 14 may include an indication marking 141 that shows the size of the wrench, trademarks, trade names, figures, or combination thereof. Alternatively, the indication area 14 is an indentation into which a board (not shown) is fixed, with the board bearing the size of the wrench, trademark, trade name, figures, characters, marks, symbols, or combination thereof.
[0033] In the examples shown in FIGS. 1 through 3 , the character units 131 are trademarks, and the indication marking 141 of the indication area 14 is a trademark identical to the character units 131 . Further, four sides of the indication marking 141 in the indication area 14 are spaced from the character units 131 .
[0034] In the example shown in FIG. 4 , some or all of the character units 131 overlap with each other to provide directionless anti-slipping effect.
[0035] In the example shown in FIG. 5 , the character units 131 are figures, and the indication marking 141 of the indication area 14 includes figures identical to the character units 131 .
[0036] In the example shown in FIG. 6 , which is modified from the example of FIG. 5 , some or all of the character units 131 overlap with each other to provide directionless anti-slipping effect.
[0037] In the example shown in FIG. 7 , the character units 131 that form the anti-slipping section 13 extend into the indication area 14 and overlap with the indication marking 141 of the indication area 14 . However, the trademark (i.e., the indication marking 141 ) in the indication area 14 is larger than each character unit 131 to provide the desired characterizing effect.
[0038] In the example shown in FIG. 8 , there are two indication areas 14 on each holding face 101 , with the indication marking 141 in each indication area 14 showing the size of the wrench.
[0039] In the example shown in FIG. 9 , there is only one indication area 14 on each holding face 101 , with the indication area 14 separating the anti-slipping section 13 into two parts, with left and right sides of the indication marking 141 in the indication area 14 being spaced from the parts of the anti-slipping section 13 , and with upper and lower sides of the indication marking 141 in the indication area 14 being free of the character units 131 .
[0040] In the examples of the present invention, the length of the indication marking 141 in the indication area 14 is preferably two to four times of that of each character unit 131 and the width of the indication marking 141 in the indication area 14 is preferably two to four times of that of each character unit 131 to provide the desired characterizing effect.
[0041] Although specific embodiments have been illustrated and described, numerous modifications and variations are still possible without departing from the essence of the invention. The scope of the invention is limited by the accompanying claims.
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A wrench includes a body having two ends and a handle between the ends of the body. At least one of the ends of the body can be used for driving an object. A plurality of character units are provided on each holding face and form an anti-slipping section. At least one of the holding faces includes at least one indication area located in the anti-slipping section. The indication area includes an indication marking.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a type of water soluble foam fire extinguishing composite material, which is a composite material with high fire extinguishing performance and environmental safety, and no toxic to the human body. Said composite material has almost no effect on the decomposition of the ozone layer, and has virtually no tendency to worsen the well-known phenomenon of greenhouse heating. In contrast, the composite material has extremely good fire extinguishing performance and ability to control the intensity of a fire. It is not toxic to the human body (and will not cause corrosion injuries), is not strongly corrosive, and will not cause the aftereffects of water fire extinguishing (such as severe water damage).
[0002] While the global economy is growing rapidly and the world population is swelling, usable land is increasing scarce. Continuous growth appears set to continue well into the future. Many countries are striving to gain more living space within their limited territories, and Taiwan is no exception to this trend. But since skyscrapers and high-rises are springing up throughout Taiwan in order to make the most of Taiwan's limited land area, high-rise safety has become increasingly important. In particular, protection against fire and fast means of fire extinguishing are vital to maintaining safe high-rise buildings. But because most people do not know how to prevent and extinguish fires, and because most ordinary homes have their own specific fire extinguishing methods, people inevitably become panicky and don't know what to do when a fire occurs. People thus often fail to use fire extinguishers in a speedy and effective manner even when they are available. And as a result, if a fire is allowed to grow too large, it may already be too late by the time fire extinguishers are used.
[0003] Two Important Factors Must be Kept in Mind When Extinguishing a Fire:
[0004] (1) Combustible materials must be kept away from air. (2) The high temperatures needed for ignition must be avoided or reduced. Because of this, people can put out small fires by covering the combustible materials with a blanket or layer of foam and thereby keeping them away from oxygen in the air. The customary response of pouring water on burning material to put out the fire works by reducing the temperature to a point where combustion cannot occur, and it can be very effective. In addition, water -can also smother a fire or separate the burning materials from the air. And because water is readily available in most ordinary homes, the first thing that appears in people's minds when a fire occurs is to use water to put the fire out. But although spraying water on a fire can put it out, the use of water in fire extinguishing can damage the structure of the building and articles in it. People often forget this fact. Nalogenated hydrocarbon fire extinguishing agents were introduced starting in the 1980's in an effort to alleviate the damage caused by the use of water in fire extinguishers. Halogenated hydrocarbon fire extinguishing agents can not only effectively put out fire, but also cause only minimal damage to buildings and objects in them.
[0005] At present the most commonly used halogenated hydrocarbon fire extinguishing agents are the brominated carbon compounds Halon 1301 (CF 3 Br) and Halon 1211 (CF 2 ClBr). It is generally accepted that these brominated fire extinguishing agents are extremely effective at extinguishing fires that are still in the early stages of growth. These fire extinguishing agents work by decomposing in the elevated temperature of a fire and generating bromine-containing products, which can block the self-sustaining combustion of free radicals. Brominated halogenated hydrocarbon fire extinguishing agents are therefore commonly used in tank-type fire extinguishers and automatic indoor spray systems triggered by fire detectors.
[0006] As has been explained, the public is aware that brominated halogenated hydrocarbon such as Halon 1211 can stop the process of combustion. But because these fire extinguishing agents contain bromine, they are very costly and toxic to humans. Because they may irritate the heart even at low concentrations, bromine-containing substances are not suitable for long-term use.
[0007] The use of brominated hydrocarbon fire extinguishing agents has encountered strong opposition in recent years because of their ability to destroy ozone in the earth's stratosphere. In particular, the role of chlorofluorocarbons (CFCs) in damaging the ozone layer has inspired great interest in the development of alternative cooling agents, solvents, and foaming agents. The public currently feels that brominated hydrocarbons such as Halon 1301 and Halon 1211 are as harmful to the ozone layer as CFCs, and their extreme stability also enables them to play a role in the further environmental problem of greenhouse warming.
[0008] As a consequence, in view of the foregoing disadvantages of halogenated hydrocarbon fire extinguishing agents and the fact that most people responding directly to the outbreak of fire try to put it out using readily-available water, the inventors have developed and extensively tested the composite material comprising this invention.
SUMMARY OF THE INVENTION
[0009] The chief goal of this invention is to provide a fire extinguishing composite material, and specifically to provide a low-cost water soluble foam fire extinguishing composite material comprising a foaming agent, sodium dodecyl benzene sulphonate (DBN), and water that is not toxic to the human body or the environment.
DETAILED DESCRIPTION OF THE INVENTION
[0010] In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope and spirit of the present invention defined in the appended claims.
[0011] The present invention is based on the discovery that the use of effective amounts of a composite material comprising a foaming agent, sodium dodecyl benzene sulphonate (DBN), and water can prevent or effectively extinguish the combustion of combustible matter. Especially when used in enclosed spaces, this composite material will not cause the decomposition of ozone in the stratosphere or worsen the so-called greenhouse effect. The composite material contains 0.5 g EMAL—a foaming agent familiar to the public—and 1.5 g of sodium dodecyl benzene sulphonate (DBN) per kilogram of water. One kilogram of the composite material can be dissolved in 500 kg of water, and can generate a fine foam at a rate of 100 mm 2 /sec. after mixing and stirring.
[0012] Apart from being harmful to people and the environment, ordinary fire extinguishers are also costly to manufacture and are sold for high prices. While small fire extinguishers are often inadequate, large fire extinguishers are bulky, awkward to hold and use, take up a lot of space, and must be used according to specific procedures. As a result, at present ordinary homes and offices are by no means universally equipped with these fire extinguishers, and water sprinklers are still the most widely accepted and used fire extinguishing method. And since most premises are equipped with fire hydrants, obtaining water is very easy and convenient. Although the use of water to extinguish a fire will cause the aforementioned problem of water damage, water is still the most commonly used method of fighting small fires in enclosed spaces such as ordinary homes and offices. Water also has the advantages of low cost and good effectiveness. In view of these considerations, when a fire occurs in an enclosed space, people can pour the composite material comprising this invention directly into a pond or water tank, so that it will cut off the combustible matter from the air. And since the composite material is almost completely harmless to people and the environment, it can also be used by hand to put out a source of fire. The composite material can be kept in a disposable plastic bottle in most circumstances. This solution is inexpensive, convenient, and allows easy storage. One liter of this composite material can be added to 500 liters of water to replace the foregoing halogenated hydrocarbons; in use it will quickly lower the temperature below the combustion point and cut off the fire's air supply.
[0013] In order to prevent a fire from becoming established in an enclosed space, the amount of gas or gases used must be sufficient to reduce the total amount of oxygen per mole in that space so as to inhibit or prevent the combustion of matter capable of sustaining fire and not spontaneously combustible.
[0014] Depending on the particular types of combustible matter present in an enclosed space, different amounts of fire extinguishing material will be needed to suppress combustion. As is commonly known, while the combustibility of a material, which is its ability to ignite and sustain combustion under known environmental conditions, will vary depending on chemical and physics characteristics such as ratio of surface area to volume, thermal capacity, porosity, and other similar factors. For instance, thin and porous sheets of tissue paper will burn more easily than solid objects.
[0015] Generally speaking, a thermal capacity of approximately 40 cal/° C. and normal oxygen per mole is sufficient to prevent or suppress combustion of most relatively combustible materials such as wood and plastic. Thermal capacity exceeding the minimum requirement should ideally be provided in the case of certain highly-combustible materials so as to achieve an extra safety margin. A minimum oxygen per mole thermal capacity of 45 cal/° C. is adequate to inhibit the burning of moderately combustible materials. The foaming agent, sodium dodecyl benzene sulphonate (DBN), and water in this composite material are able to achieve this value.
[0016] The present invention is thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
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A type of water soluble foam fire extinguishing composite material includes a foaming agent, sodium dodecyl benzene sulphonate (DBN), and water. Said sodium dodecyl benzene sulphonate (DBN) is a replacement for halogenated hydrocarbons, and exerts an extremely great effect on cooling and control of the intensity of a fire; because it has almost no effect on ozone in the stratosphere, it will not worsen global warming.
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FIELD OF THE INVENTION
This invention relates to immunogenetics and to peptide chemistry. More particularly, it relates to a class of nonapeptides useful in various ways, such as immunogens and as materials which target and bind MHC/HLA molecules, as well as a cellular model useful in the testing of peptides and other molecules as vaccines, especially cancer vaccines. Most particularly, it relates to the so-called "tumor rejection antigens", in particular the MAGE family of these antigens.
BACKGROUND AND PRIOR ART
The study of the recognition or lack of recognition of cancer cells by a host organism has proceeded in many different directions. Understanding of the field presumes some understanding of both basic immunology and oncology.
Early research on mouse tumors revealed that these displayed molecules which led to rejection of tumor cells when transplanted into syngeneic animals. These molecules are "recognized" by T-cells in the recipient animal, and provoke a cytolytic T-cell response with lysis of the transplanted cells. This evidence was first obtained with tumors induced in vitro by chemical carcinogens, such as methylcholanthrene. The antigens expressed by the tumors and which elicited the T-cell response were found to be different for each tumor. See Prehn, et al., J. Natl. Canc. Inst. 18:769-778 (1957); Klein et al., Cancer Res. 20: 1561-1572 (1960); Gross, Cancer Res. 3: 326-333 (1943), Basombrio, Cancer Res. 30:2458-2462 (1970) for general teachings on inducing tumors with chemical carcinogens and differences in cell surface antigens. This class of antigens has come to be known as "tumor specific transplantation antigens" or "TSTAs". Following the observation of the presentation of such antigens when induced by chemical carcinogens, similar results were obtained when tumors were induced in vitro via ultraviolet radiation. See Kripke, J. Natl. Canc. Inst. 53: 333-1336 (1974).
While T-cell mediated immune responses were observed for the types of tumor described Supra, spontaneous tumors were thought to be generally non-immunogenic. These were therefore believed not to present antigens which provoked a response to the tumor in the tumor carrying subject. See Hewitt, et al., Brit. J. Cancer 33: 241-259 (1976).
The family of tum - antigen presenting cell lines are immunogenic variants obtained by mutagenesis of mouse tumor cells or cell lines, as described by Boon et al., J. Exp. Med. 152: 1184-1193 (1980), the disclosure of which is incorporated by reference. To elaborate, tum - antigens are obtained by mutating tumor cells which do not generate an immune response in syngeneic mice and will form tumors (i.e., "tum + " cells). When these tum + cells are mutagenized, they are rejected by syngeneic mice, and fail to form tumors (thus "tum - "). See Boon et al., Proc. Natl. Acad. Sci. USA 74: 272 (1977), the disclosure of which is incorporated by reference. Many tumor types have been shown to exhibit this phenomenon. See, e.g., Frost et al., Cancer Res. 43: 125 (1983).
It appears that tum - variants fail to form progressive tumors because they elicit an immune rejection response. The evidence in favor of this hypothesis includes the ability of "tum - " variants of tumors, i.e., those which do not normally form tumors, to do so in mice with immune systems suppressed by sublethal irradiation, Van Pel et al., Proc. Natl, Acad. Sci. USA 76: 5282-5285 (1979); and the observation that intraperitoneally injected tum - cells of mastocytoma P815 multiply exponentially for 12-15 days, and then are eliminated in only a few days in the midst of an influx of lymphocytes and macrophages (Uyttenhove et al., J. Exp. Med. 152: 1175-1183 (1980)). Further evidence includes the observation that mice acquire an immune memory which permits them to resist subsequent challenge to the same tum - variant, even when immunosuppressive amounts of radiation are administered with the subsequent challenge of cells (Boon et al., Proc. Natl, Acad. Sci. USA 74: 272-275 (1977); Van Pel et al., supra; Uyttenhove et al., supra).
Later research found that when spontaneous tumors were subjected to mutagenesis, immunogenic variants were produced which did generate a response. Indeed, these variants were able to elicit an immune protective response against the original tumor. See Van Pel et al., J. Exp. Med. 157: 1992-2001 (1983). Thus, it has been shown that it is possible to elicit presentation of a so-called "tumor rejection antigen" in a tumor which is a target for a syngeneic rejection response. Similar results have been obtained when foreign genes have been transfected into spontaneous tumors. See Fearson et al., Cancer Res. 48: 2975-1980 (1988) in this regard.
A class of antigens has been recognized which are presented on the surface of tumor cells and are recognized by cytotoxic T cells, leading to lysis. This class of antigens will be referred to as "tumor rejection antigens" or "TRAs" hereafter. TRAs may or may not elicit antibody responses. The extent to which these antigens have been studied has been via cytolytic T cell characterization studies in vitro i.e., the study of the identification of the antigen by a particular cytolytic T cell ("CTL" hereafter) subset. The subset proliferates upon recognition of the presented tumor rejection antigen, and the cells presenting the antigen are lysed. Characterization studies have identified CTL clones which specifically lyse cells expressing the antigens. Examples of this work may be found in Levy et al., Adv. Cancer Res. 24: 1-59 (1977); Boon et al., J. Exp. Med. 152: 1184-1193 (1980); Brunner et al., J. Immunol. 124: 1627-1634 (1980); Maryanski et al., Eur. J. Immunol. 124: 1627-1634 (1980); Maryanski et al., Eur. J. Immunol. 12: 406-412 ( 1982); Palladino et al., Canc. Res. 47: 5074-5079 (1987). This type of analysis is required for other types of antigens recognized by CTLs, including minor histocompatibility antigens, the male specific H-Y antigens, and a class of antigens, referred to as "tum-" antigens, and discussed herein.
A tumor exemplary of the subject matter described supra is known as P815. See DePlaen et al., Proc. Natl. Acad. Sci. USA 85: 2274-2278 (1988); Szikora et al., EMBO J 9: 1041-1050 (1990), and Sibille et al., J. Exp. Med. 172: 35-45 (1990), the disclosures of which are incorporated by reference. The P815 tumor is a mastocytoma, induced in a DBA/2 mouse with methylcholanthrene and cultured as both an in vitro tumor and a cell line. The P815 line has generated many tum - variants following mutagenesis, including variants referred to as P91A (DePlaen, supra), 35B (Szikora, supra), and P198 (Sibille, supra). In contrast to tumor rejection antigens--and this is a key distinction--the tum - antigens are only present after the tumor cells are mutagenized. Tumor rejection antigens are present on cells of a given tumor without mutagenesis. Hence, with reference to the literature, a cell line can be tum + , such as the line referred to as "P1" and can be provoked to produce tum - variants. Since the tum - phenotype differs from that of the parent cell line, one expects a difference in the DNA of tum - cell lines as compared to their tum + parental lines, and this difference can be exploited to locate the gene of interest in tum - cells. As a result, it was found that genes of tum - variants such as P91A, 35B and P198 differ from their normal alleles by point mutations in the coding regions of the gene. See Szikora and Sibille, supra, and Lurquin et al., Cell 58: 293-303 (1989). This has proven not to be the case with the TRAs of this invention. These papers also demonstrated that peptides derived from the tum - antigen are presented by the L d molecule for recognition by CTLs. P91A is presented by L d , P35 by D d and P198 by K d .
PCT application PCT/US92/04354, filed on May 22, 1992 assigned to the same assignee as the subject application, teaches a family of human tumor rejection antigen precursor coding genes, referred to as the MAGE family. Several of these genes are also discussed in van der Bruggen et al., Science 254: 1643 (1991). It is now clear that the various genes of the MAGE family are expressed in tumor cells, and can serve as markers for the diagnosis of such tumors, as well as for other purposes discussed therein. See also Traversari et al., Immunogenetics 35: 145 (1992); van der Bruggen et al., Science 254: 1643 (1991). The mechanism by which a protein is processed and presented on a cell surface has now been fairly well documented. A cursory review of the development of the field may be found in Barinaga, "Getting Some Backbone: How MHC Binds Peptides" Science 257: 880 (1992); also, see Fremont et al , Science 257: 919 (1992); Matsumura et al., Science 257: 927 (1992); Latron et al., Science 257: 964 (1992). These papers generally point to a requirement that the peptide which binds to an MHC/HLA molecule be nine amino acids long (a "nonapeptide"), and to the importance of the first and ninth residues of the nonapeptide.
Studies on the MAGE family of genes have now revealed that a particular nonapeptide is in fact presented on the surface of tumor cells, and that the presentation of the nonapeptide requires that the presenting molecule be HLA-A1. Complexes of the MAGE-1 tumor rejection antigen (the "TRA" or nonapeptide") leads to lysis of the cell presenting it by cytolytic T cells ("CTLs"). This observation has both diagnostic and therapeutic implications, as discussed herein.
It has also been found that, when comparing homologous regions of various MAGE genes to the region of the MAGE-1 gene coding for the relevant nonapeptide, there is a great deal of homology. Indeed, these observations lead to one of the aspects of the invention, which is a family of nonapeptides all of which have the same N-terminal and C-terminal amino acids. These nonapeptides can be used for various purposes which includes their use as immunogens, either alone or coupled to carrier peptides. Nonapeptides are of sufficient size to constitute an antigenic epitope, and the antibodies generated thereto may then be used to identify the nonapeptide, either as it exists alone, or as part of a larger polypeptide.
The nonapeptides may also be used as agents to identify various HLA subtypes on the surface of tumor cells, such as melanomas. Via this ability, they may serve either as diagnostic markers, or as therapeutic agents. These features are discussed infra.
Also considered part of the invention are the nucleic acid sequences which code for the nonapeptides. These nucleic acid sequences may serve as diagnostic probes for tumor presence.
It has also been found that a cellular model can now be used, wherein a non-human cell can be transfected with a nucleic acid sequence coding for a human HLA molecule. The resulting transfectant can then be used to test for nonapeptide specificity of the particular HLA molecule, or as the object of a second transfection with a MAGE gene. The co-transfectant can then be used to determine whether the particular MAGE based TRA is presented by the particular HLA molecule. These, and other features of the invention, are set forth in the description which follows.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 outlines the procedure by which a 300 base pair fragment of MAGE-1 gene was identified as coding for the relevant tumor rejection antigen.
FIG. 2 shows lytic studies in which cells were incubated with various MAGE-1 peptides.
FIG. 3A compares lysis of a cell line (P1.HTR) which does not express HLA-A1, with an HLA-A1 transfectant (P1.HTR.A1), and an E - antigen loss cell line variant (MZ2+MEL 2.2), with and without the peptide Glu Ala Asp Pro Thr Gly His Ser Tyr (SEQ ID NO: 1) being present.
FIG. 3B compare E + antigen cell line MZ2-MEL and cell line P1.A1 MAGE-1, which is cell line P1.HTR.A1 cotransfected with MAGE-1 cDNA, under the same condition as for FIG. 3B.
FIG. 4 compares nonapeptides from various homologous sections of MAGE genes and the nucleic acid sequences coding for these nonapeptide.
SEQ ID NOS: 1-9 show homologous nonapeptides from MAGE genes and the nucleic acid sequences coding for these.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
EXAMPLE 1
The 2.4 Kb BamIII fragment, described by van der Bruggen et al., Science 254: 1643 (1991), the disclosure of which is incorporated by reference, is known to contain only exons 2 and 3 of the gene coding for MAGE-1 protein. The fragment transfers expression of antigen MZ2E to E - antigen loss cell line variant MZ2-MEL .2.2, and leads to lysis of the transfectants by E + CTLs. Previous work by DePlaen et al., Proc. Natl. Acad. Sci. USA 85: 2274 (1988), and Chomez et al., Immunogenetics 35: 241 (1990), had established that small gene fragments containing antigen peptide coding sequences regularly express those antigens, even when not transfected in the form of expression vectors. In view of these observations, experiments were carried out with smaller fragments of the 2.4 kb fragment. Various restriction enzymes were used to cut the 2.4 kb fragment into smaller fragments. The resulting, smaller fragments were cloned into plasmid vector pTZ18R. A 300 base pair fragment taken from exon 3 was obtained via polymerase chain reaction ("PCR") amplification, using oligonucleotides VDB 14:
5'-CAGGGAGCCAGTCACAAAG-3' (SEQ ID NO: 21)
and CHO 9:
5'-ACTCAGCTCCTCCCAGATTT-3' (SEQ ID NO. 22)
These primers amplify a 300 base pair fragment of MAGE-1, between positions 422 and 722 of exon 1. The fragment was cloned into expression vector PSVK3. The new constructs were cotransfected with plasmid pSVtkneoβ into the MZ2.MEL 2.2 cell lines. This was accomplished using the calcium phosphate precipitation method (Traversari et al., Immunogenetics 35: 145 (1992); Wolfel et al., Immunogenetics 26: 178 (1987)), using 4×10 6 cells and 3 ug of pSVtneoβ (Nicolas et al., CSH Conf. Cell Prolif 10: 469 (1983)), and 30 ug of the ptZ18R or PSVK3 constructs. The transfectants were then selected in medium containing neomycin analog G418. Fifteen days after transfection, resistant cells were tested for their ability to stimulate TNF production by the anti-E antigen CTL 82/30. This was accomplished by adding 100 ul samples, containing 1500 CTL 82/30 to 4×10 4 transfected cells. Supernatant samples (50 ul) were harvested and added to 3×10 4 WEHI 164 clone 13 cells (Espevik et al., J. Immunol. Meth. 95:99 (1986), to evaluate TNF presence. Mortality of WEHI cells was estimated 24 hours later, using an MTT colorimetric assay as per, e.g., Traversari et al., supra.
As shown in FIG. 1, these experiments identified a 300 base pair fragment from MAGE-1 exon 3 capable of efficient transferring of expression of antigen MZ2E.
EXAMPLE 2
The MAGE-1 gene belongs to a family of several highly related genes van der Bruggen et al., supra. Prior experiments had noted that MAGE-2 and MAGE-3 did not direct expression of antigen MZ2E. As the 300 base pair fragment clearly did, the homologous sections of MAGE-2 and MAGE-3 genes were compared to the 300 base pair fragment. Differences were clear, and several 15 amino acid peptides were synthesized, using F-moc for transient N-terminal protection, in accordance with Atherton et al., J. Chem. Soc. 1: 538 (1981). The peptides were purified by C-18 reverse phase HPLC, and characterized by amino acid analysis.
Once the peptides were secured, they were tested in lysis assays, using the chromium release methodology of Boon et al., J. Exp. Med. 152: 1184 (1980). Briefly, 1000 51 Cr labeled E - target cells were incubated in 96 well microplates, using various concentrations of peptides for 30 minutes at 37° C.
An equal volume of CTL containing sample was added (cell line 82/30), the number of CTLs being five times that of their target. Chromium release was measured after four hours. Sensitization of E - cells to lysis by the anti E CTLs was observed with a peptide that corresponds to codons 158-172 of the large open reading frame of MAGE-1. Shorter peptides were prepared and efficient lysis was observed with peptide: Glu Ala Asp Pro Thr Gly His Ser Tyr (SEQ ID NO:).
The results, shown in FIG. 2, demonstrate that the first and ninth amino acids were critical for binding and effecting lysis. This is in accordance with prior reports stating that MHC-I molecules generally are bound by nonapeptides (Rotzschke et al., Nature 348: 252 (1990)). FIG. 2 also shows that half maximum lysis was obtained at a peptide concentration of 5 nM.
EXAMPLE 3
Experiments were carried out to determine what molecule presented the relevant MAGE-1 antigen. To accomplish this, an HLA-A1 gene, as taught by Girdlestone, Nucl. Acids. Res. 18: 6701 (1990), was transfected into a mouse cell line, P1.HTR. This line is a highly transfectable variant of mouse mastocytoma cell line P815. The resulting transfectants, referred to as "P1.HTR.A1", were incubated in the presence of the nonapeptide discussed supra, using the same lysis assay. Controls were also used.
FIG. 3 shows that the cell line was lysed, showing that a model has been developed for screening for a lytic peptide, using a non-human cell.
In experiments not described herein, similar results were obtained with COS cells.
Additional experiments were also carried out, in which cell line P1.HTR A1 was transfected with MAGE-1 cDNA. When the lytic assay of Example 2 was carried out with this co-transfected cells, it was found that they were also lysed.
EXAMPLE 4
Given the homology of the various genes within the MAGE family, a comparison was carried out to identify similarities amongst the homologous regions of the genes. These regions are shown in FIG. 4. These peptides and the nucleic acid sequences coding for them, are not identical, but show a great deal of homology, especially the identical first and ninth residues.
The foregoing examples show that a nonapeptide derived from MAGE-1 is presented by HLA-A1 molecules, and cells presenting the complex of HLA-A1 and the nonapeptide are recognized and lysed by specific CTL cells. This observation indicates that nonapeptides in accordance with the invention may be used both therapeutically and diagnostically.
In the case of the latter category of use, the nonapeptides may be used, for example, to identify tumors expressing a particular HLA molecule, or cancer cells per se. One contacts a cancer cell containing sample or a tumor cell with a nonapeptide which binds thereto, and combines the material with a CTL sample specific for the complex. If lysis ensues, then the tumor/cancer cell can be typed with respect to the HLA molecule thus expressed.
Therapeutically, there are two major ways in which the nonapeptide may be used. In an in vivo therapeutic approach, the nonapeptides may be administered in a way which targets them to tumors to be treated. This can be done via direct injection, time release administration, coupling to tumor specific antibodies, and so forth. Upon binding the requisite HLA molecule, there is a CTL response, leading to lysis of the tumor. Of course, in such a therapeutic approach, the nonapeptide is administered in an amount sufficient to lead to lysis of the tumor. This amount will vary, based upon the particular patient, the type and size of the tumor, and so forth.
An "in vitro" form of therapy is also contemplated. As indicated supra, when the pertinent HLA molecule binds to a MAGE nonapeptide, if contacted with the CTLs specific for the peptide/HLA complex, a CTL proliferative response occurs. As the CTLs are the agents of tumor lysis in vivo, the resulting expanded populations may be administered to the patient. The CTLs can be expanded by using the patient's own blood or any other source of CTLs, or by contact to samples of peptide specific CTLs which have previously been established. In this regard, note that CTL 82/30, discussed supra had been available for some time as was the methodology for its development.
Therapies of the type described herein are particularly useful for melanoma. Analysis of samples has shown that about 40% of all melanoma tumors express MAGE-1, and the HLA-A1 allele is present in about 26% of the caucasian population at large. Thus, at the least, 10% of the caucasian melanoma population may be treated in this fashion. The patients may also be treated with non-proliferative cells which have complexes of HLA-A1 and the MAGE 1 presented on their surface.
The MAGE-1 derived nonapeptide appears to be HLA-A1 specific. Although the MAGE-2, MAGE-3 and MAGE-4 genes have all been observed to be expressed in HLA-A1 cells of tumors, the peptides corresponding to MAGE-1 have not been shown to elicit the same specific CTL response; however it may be expected that these nonapeptides do provoke response by different CTLs when bound to an appropriate HLA molecule.
The nucleic acid sequences, as indicated, may be used in a variety of ways. MAGE genes are expressed in tumors, and thus the nucleic acid sequences may be used a probes to identify tumor cells. This can be accomplished via labelled hybridization probes, PCR, or any of the various nucleic acid probe based assays known to the art.
The development of the non-human cell lines described herein presents a unique way to carry out some of the features of the invention described herein. The examples show, e.g., that the CTLs recognize the complex of HLA and nonapeptide, and do not appear to differentiate between the cell types which present the complexes. Thus, the isolated, non-human cell lines of the invention can be used to generate CTLs, and to identify their presence in human samples.
As indicated, the invention also involves isolated non-human cell lines transfected with both an HLA gene, and a sequence coding for a nonapeptide, such as HLA-A1 and MAGE-1 nonapeptide. One is not limited to transfection with one HLA coding gene and one MAGE peptide, and indeed the invention contemplates polytransfected cells, which may contain more than one HLA gene and more than one MAGE antigen coding sequence. Such cells may be regarded as universal effector cells, as the presence of appropriate pairs of HLA and peptide on the surface will lead either to identification of specific CTLs of choice, or to generation of CTL proliferation in a therapeutic context. Such cells, be they cotransfected or polytransfected, may serve as vaccines when combined with a suitable adjuvant, such as those well known to the art. Treatment of various cancerous conditions, such as melanoma and breast cancer, may be carried out using these transfectant.
The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, it being recognized that various modifications are possible within the scope of the invention.
__________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 22(2) INFORMATION FOR SEQ ID NO: 1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(ix) FEATURE:(A) NAME/KEY: MAGE-1 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 1:GluAlaAspProThrGlyHisSerTyr(2) INFORMATION FOR SEQ ID NO: 2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(ix) FEATURE: (A) NAME/KEY: MAGE-2 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2:GluValValProIleSerHisLeuTyr5(2) INFORMATION FOR SEQ ID NO: 3:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein (ix) FEATURE:(A) NAME/KEY: MAGE-21 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 3:GluValValArgIleGlyHisLeuTyr5(2) INFORMATION FOR SEQ ID NO: 4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(ix) FEATURE:(A) NAME/KEY: MAGE-3 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4:GluValAspProIleGlyHisLeuTyr5(2) INFORMATION FOR SEQ ID NO: 5:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(ix) FEATURE:(A) NAME/KEY: MAGE-4 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 5:GluValAspProAlaSerAsnThrTyr5(2) INFORMATION FOR SEQ ID NO: 6:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(ix) FEATURE:(A) NAME/KEY: MAGE-41 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 6:GluValAspProThrSerAsnThrTyr5(2) INFORMATION FOR SEQ ID NO: 7:(i ) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(ix) FEATURE:(A) NAME/KEY: MAGE-5 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7:GluAlaAspProThrSerAsnThrTyr5 (2) INFORMATION FOR SEQ ID NO: 8:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(ix) FEATURE:(A) NAME/KEY: MAGE-5 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 8:GluAlaAspProThrSerAsnThrTyr 5(2) INFORMATION FOR SEQ ID NO: 9:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(ix) FEATURE:(A) NAME/KEY: MAGE-6 derived nonapeptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 9:GluValAspProIleGlyHisVa lTyr5(2) INFORMATION FOR SEQ ID NO: 10:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(ix) FEATURE:(A) NAME/KEY: MAGE-1 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 10: GAAGCAGACCCCACCGCCCACTCCTAT27(2) INFORMATION FOR SEQ ID NO: 11:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(ix) FEATURE: (A) NAME/KEY: MAGE-2 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11:GAAGTGGTCCCCATCAGCCACTTGTAC27(2) INFORMATION FOR SEQ ID NO: 12:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(ix) FEATURE:(A) NAME/KEY: MAGE-21 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 12:GAAGTGGTCCGCATCGGCCACTTGTAC27(2) INFORMATION FOR SEQ ID NO: 13:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(ix) FEATURE:(A) NAME/KEY: MAGE-3 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 13:GAAGTGGACCCCATCGGCCACTTGTAC27(2) INFORMATION FOR SEQ ID NO: 14:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(ix) FEATURE:(A) NAME/KEY: MAGE-4 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 14:GAAGTGGACCCCGCCAGCAACACCTAC 27(2) INFORMATION FOR SEQ ID NO: 15:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(ix) FEATURE:(A) NAME/KEY: MAGE-41 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 15:GAAGTGGACCCCACCAG CAACACCTAC27(2) INFORMATION FOR SEQ ID NO: 16:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(ix) FEATURE:(A) NAME/KEY: MAGE-5 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 16:GAAGCGGACCCCACCAGCAACACCTAC27(2) INFORMATION FOR SEQ ID NO: 17:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(i x) FEATURE:(A) NAME/KEY: MAGE-51 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 17:GAAGCGGACCCCACCAGCAACACCTAC27(2) INFORMATION FOR SEQ ID NO: 18:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 27 base pairs(B) TYPE: nucleic acids(C) STRANDEDNESS: single (D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(ix) FEATURE:(A) NAME/KEY: MAGE-6 nonapeptide coding sequence(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 18:GAAGTGGACCCCATCGGCCACGTGTAC27(2) INFORMATION FOR SEQ ID NO: 19:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 19 base pairs (B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 19:CAGGGAGCCAGTCACAAAG19(2) INFORMATION FOR SEQ ID NO: 20:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 20 base pairs (B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: DNA(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 20:ACTCAGCTCCTCCCAGATTT20(2) INFORMATION FOR SEQ ID NO: 21:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 8 amino acid residues(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 21:GluAlaAspProThrGlyHisSer5(2) INFORMATION FOR SEQ ID NO: 22:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 8 amino acid residues(B ) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 22:AlaAspProTrpGlyHisSerTyr5
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The invention involves the reception of particular nonapeptides by HLA molecules. The nonapeptides are derived from expression products of the MAGE gene family. The resulting complexes are identified by cytolytic T cells. Such recognition may be used in diagnostics, or therapeutically.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improved method and apparatus for controlling the plating thickness on a metal strip which is passed through an electrochemical plating line.
A typical plating line has a plating bath through which a workpiece to be plated is moved. As the workpiece is moved through the plating bath, it is maintained at a substantially constant electrical potential relative to a number of plating electrodes positioned in the bath. The potential difference is maintained between the plating electrodes and the workpiece by a number of rectifier units.
As the workpiece moves through the bath, electrically charged ions in that bath combine with electrons from the recitifier units to form a plating which coats the workpiece. The number of these combinations of ions and electrons, per unit time, represents the plating current within the plating bath. The total plating current in the plating line is equal to the sum of the plating currents from the individual electrodes or rectifier units.
The magnitude of the plating current is dependent upon a number of system variables. It is known within the art, that the input voltage to the rectifiers, the spacing between the electrodes and the workpieces, and the physical condition of the electrodes, all affect the magnitude of the plating current.
In one typical operation, the workpiece is a strip of steel which is passed through the bath in order that a galvanizing coating of zinc may be deposited on its surface. A coil of un plated strip is unwound, plated in the bath, and then rewound as a plated coil. The details of a typical plating arrangement whose efficiency can be improved by the present invention can be found in U.S. Pat. No. 3,468,783 to Avellone which has been assigned to Republic Steel Corporation and which is incorporated by reference here.
2. Description of the Prior Art
For a strip such as that described in the Avellone patent, and for a given length of travel through the bath, the plating thickness is a function of the plating current, the speed with which the strip moves through the bath, and the physical dimensions of the strip. Since it is the plating thickness that an operator is interested in controlling, the above three factors must be taken into account when setting up plating operations. If, for example, the plating current is the only physical parameter controlled, unintended changes in line speed as the strip moves through the bath will affect the plating thickness in an adverse manner. If the plating current is kept constant and the physical dimensions of the object or workpiece are changed, plating thickness will also change. For these reasons, optimum plating thickness can only be achieved through a close monitoring of not only the plating current but also of the speed of the object through the bath and the physical dimensions of the object.
If the physical dimensions of the object or workpiece to be plated and the speed with which the object or workpiece through the media are known, the proper total plating current for a given plating thickness can be calculated. In the past, these calculations were performed for different combinations of the plating material dimensions and plating line speed, and charts expressing the results of the calculation were provided to inform the operator of the correct plating current.
The use of a chart or tabulation often occasioned errors by the operator when calculating the proper plating current for the optimum plating thickness. Sometimes, an operator, in an effort to increase plating production, would increase the speed with which the workpiece moved through the medium without making the needed adjustments in the plating current.
Even if the operator made accurate adjustments for increased plating current, these adjustments could cause the plating rectifiers to exceed their rated current capability. As the operator attempted to increase the speed with which the product was plated (and thereby increase his production), the plating current was also increased and at some point the capacity of the rectifiers was exceeded. When the capacity of a rectifier was exceeded either a circuit breaker was actuated with resultant reduction in production capacity, or even worse, damage to the rectifier occurred producing a reduction in capacity for a longer period of time.
As noted previously, the plating current can also be adjusted by changing the spacing between the electrodes and the workpiece. As an operator attempted to increase the plating current and therefore his production, he would sometimes reposition the electrodes to a position in closer proximity to the object to be plated. Such readjustment sometimes inadvertently brought the electrode in contact with the plating object, causing a short circuit. The resultant high current levels could damage the connected rectifier unit, with the result that total production decreased rather than increased.
When the plating line included a number of electrodes, it was sometimes possible for the prior user to satisfactorily control total plating current, but he had no way of knowing whether this plating current was being efficiently distributed among the large number of rectifier units on the line. Typically, rectifier current levels vary among the units, due for example to nonuniformity in condition of electrodes. Some operate at or near capacity, while others operate at much lower current. Those operating at high levels carry most of the load while the rectifiers at lower current levels operate inefficiently.
A technique for controlling individual plating current in a plating rectifier has been proposed. The thrust of the proposal, is toward maintaining the rectifiers within safe operating parameters, with no regard to apportionment of plating currents. Specifically, each rectifier unit is current limited to maintain the rectifier operating temperature below a maximum safe operating level. The speed of strip movement is apparently controlled as a function of total plating current while operating parameters are monitored. The proposal does not however, describe the manner of the control.
SUMMARY OF THE INVENTION
The present invention overcomes inefficiencies associated with prior art plating line operations. An apparatus made in accordance with the invention requires no plating charts and eliminates the possibility of operator induced error due to misapplication of those charts. Each of a number of plating rectifiers are automatically controlled so that the total current is correctly provided to achieve proper plating thickness on the work material. The currents are apportioned among the rectifiers thereby producing most efficient rectifier operation. Control circuitry is included to prevent the user from extending each of the individual rectifiers beyond its rated capacity.
The invention provides an automatic system for apportioning a plating current among a number of plating rectifiers. According to the invention, the system includes a first feedback control for regulating the total plating current and a number of secondary feedback control each associated with a different one of a number of plating rectifiers. Each of these secondary feedback controls maintain the proper plating current in each of its associated rectifier. The first feedback control responds to inputs programmed by the user and sends a control signal to each of the secondary feedback controls which control operation of the plating rectifiers.
The output of each of these secondary controls can ultimately affect the size of the inputs to the other secondary control circuits. A change in the output of any feedback circuit affects the input to the other feedback circuits and vice-versa. The result of this circuitry interaction is a controlled distribution of current outputs from each of the rectifiers and a total current output equal to a total optimum value. These features reduce operator decisions regarding plating line operation with the result that fewer operator dependent errors are introduced into the system. The plating rectifier units also share their load in the most efficient manner by proportionally sharing the plating current.
A more specific embodiment of the invention includes a reference generator for providing a control or reference signal. This reference signal interacts with the two feedback control circuits to provide efficient plating line operation. The reference generator includes a speed related signal generator such as a tachometer which produces a signal proportional to the speed with which a workpiece moves along the plating line. A multi-turn reostat serves as a potential divider to reduce the signal from the tachometer in proportion to the width of the product material and the desired thickness of the plating coat. In this way, a reference signal functionally related to the plating speed, width, and thickness is provided. When one of the latter two variables is altered, the operator changes a control dial which varies the potential divider, thereby changing the portion of the tachometer signal sent to the first and second feedback circuits.
Input changes in the plating width and plating thickness, directly affect operation of the first and second feedback circuits. No charts are needed and the potential for operator induced error is substantially reduced. Due to the operation of the feedback circuitry, potential adjustments are made on each of the rectifiers in response to the input changes.
The control signal produced by the control generator is transmitted to the first feedback circuit. According to the preferred embodiment of the invention, the first feedback circuit includes a comparing amplifier for producing an error signal and a summing amplifier for adding the error signal to the control signal. The comparing amplifier receives two inputs, one from the control signal generator and one from a current totalizing amplifier. The current totalizing amplifier receives signals proportional to the current in each of a number of individual plating rectifiers and adds them together to produce an output proportional to the sum of the currents in the rectifiers. This output is compared to the control signal generator output in the comparing amplifier. The comparison produces a signal proportional to the difference between the actual sum of the current in the plating rectifiers and an optimized current as indicated by the control signal generator. This error signal is either positive or negative depending on whether the plating rectifiers are under or over producing in relation to the control signal.
The error signal is added to the control signal from the control signal generator in the summing amplifier. In this way, a modified control signal is produced. The magnitude of this modified control signal is dependent upon operation of the plating rectifiers. If the rectifiers, as a group, are underproducing, the modified control signal will be adjusted to produce a signal proportional to the magnitude of this under production. If the rectifiers are over producing, the modified control signal will give an indication of the magnitude by which they are over producing.
The modified control signal affects operation of the individual plating rectifiers through a number of secondary feedback circuits. Each secondary feedback circuit compares the modified control signal with a signal proportional to the plating current in its associated rectifier circuit. If the particular rectifier associated with a secondary feedback circuit is not producing enough current, its secondary feedback circuit will respond in a manner which will cause the rectifier to produce more current. If, on the other hand, the rectifier associated with the secondary feedback circuit is over producing, the circuit will provide a control signal which will cause the rectifier to produce less current.
The changes provided by either the first feedback circuitry or any of the number of secondary feedback circuits will affect all other circuits within the system. A change in production by any of the rectifiers will affect the modified control signal produced by the first feedback circuit which will in turn affect the output of each of the individual secondary feedback circuits. The feedback circuitry will continue to interact and produce control signals until all rectifiers are producing an optimum current and the total of these currents adds to a current which will produce a proper plating thickness. Once this advantageous state of affairs is reached, it will be maintained so long as no changes occur in operation of the individual rectifiers and the line operator makes no changes in either plating speed, coating thickness, or material width.
The system continues to optimize total current even when one or more rectifiers are incapable of providing their apportioned share. Thus if one rectifier cannot provide its proper current the other rectifiers will provide slightly more than their alotted share to maintain total current optimization.
Should the operator wish to make a change in any of the three independent variables (i.e., speed, width, or thickness), the control generator is modified accordingly. When this procedure is followed, the first and second feedback circuits will automatically adjust to equally apportion the current among the individual rectifiers and produce a total current equal to the current dictated by the change introduced by the operator.
The preferred design includes a number of specialized circuits which add flexibility and efficiency to the invention. The system includes, for example, an automatic/manual switch for changing the operation of the system. When the automatic mode of operation is selected, the first feedback circuit operates in the manner described. When the switch is thrown to the manual position, the first feedback circuit operates in a slightly different manner. When in the manual mode, the first feedback circuit receives a signal from the control generator but does not modify the signal in response to the actual currents appearing in the plating rectifiers. When operating in the manual mode, therefore, each of the secondary feedback circuits receives on unmodified control signal from the control generator.
An inoperative rectifier switch is included in the control signal generator. This switch serves to change the magnitude of the control signal in response to conditions occurring within the plating line. Due to any one of a number of reasons, one or more rectifiers within the line may become partially or totally inoperative. When this reduction in operative rectifiers occurs, the signal from the control generator is modified accordingly.
To so modify its output, the signal generator includes an operational amplifier whose output is variable depending upon the number of rectifiers operating on the line. When a rectifier becomes inoperative, the operator changes the position of a multi-contact switch, thereby increasing the output on the operational amplifier. Should a second rectifier become inoperative, the operator again changes the switch position and again the output of that operational amplifier is increased. When the rectifiers have been repaired and replaced in the operating line the operator shifts the switch back to its original position.
Each of the individualized secondary feedback circuits includes a current limiter circuit which adds to the efficiency of the invention'operation. The current limiter automatically limits to a safe maximum value the amount of current load the associated plating rectifier can produce.
All circuitry included in the invention is analog electronics. The analog electronics is less susceptible to noise and industrial transients which might produce faulty or erroneous signals within a digital circuit. The analog circuitry provides a smooth double feedback current control which automatically responds to operating conditions and to control signals introduced by the operator.
The system also includes a number of current meters which allow the user to monitor the functioning of the system. Each plating rectifier includes a current meter as well as a voltage meter for determining operation parameters of that rectifier. Also included in the system is a meter which is indicative of the total plating current. The operator will be able to monitor the actual total plating current on this meter and compare it to an optimized plating current thereby determining if the system is properly functioning.
From the above it is clear that one object and feature of the present invention is to provide an automatic technique for apportioning a precise total plating current among a number of individual plating rectifiers on a plating line. The system enables the user to automatically input the plating parameters and thereby control the operation of the individual plating rectifiers. The system also provides circuitry for allowing the operator to respond to different operating conditions as those conditions occur. Other features and advantages of the invention will become apparent as the invention becomes better understood when considered in conjunction with the following drawings and detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective schematic view of a plating line.
FIG. 2 is a schematic diagram illustrating a feedback plating control circuit.
FIG. 3 is a detailed schematic diagram illustrating one portion of the circuit of FIG. 2.
FIG. 4 is a representative chematic diagram of an individual plating rectifier feedback circuit.
FIG. 5 is a schematic showing the voltage control of an individual plating rectifier.
DETAILED DESCRIPTION OF THE INVENTION
A plating line 10 including a vat 12 of plating solution through which a workpiece or sheet of product material 14 passes is shown schematically in FIG. 1. The product 14 is caused to move through the solution by appropriate drive means which have been shown schematically in the diagram as drive rollers 16. Located on either side of the vat are support structures 18 which hold a number of electrodes 20. These electrodes supply a plating current which coats the material or workpiece with a plating film. As the plating material 14 passes through the solution within the vat 12, leakage of the solution through a pair of vat openings 13 occurs. Plating solution leaks down into containers 22 at either end of the solution from these openings. The solution in the containers 22 is periodically returned to the vat 12 and reused.
A source of electrical energy 26 produces a potential difference between the material 14 and the electrodes 20. The rollers 16 are maintained at the same electrical potential as the material 14 by means of a contact between the two at a point exterior to the solution. As shown in the diagram, the rollers are electrically connected to the grounded side of the electrical source 26. Since the material 14 is in contact with the rollers, it also is electrically grounded. The electrodes 20 are electrically connected to the nongrounded potential side of the energy source and therefore are maintained at a potential value other than ground.
As the material 14 passes through the solution, the potential difference between the material and the electrodes 20 causes a plating current to flow in the solution. This plating current might typically be used to produce galvanized steel by depositing a layer of zinc on the plating material 14 which is a sheet of steel. It is the potential difference between the material 14 and the electrodes 20 which causes the plating to occur on the surface of the material 14. The plating current is therefore an indication of how fast the plating process is occurring on the material. A high plating current in the electrodes indicates the plating process is occurring rapidly and therefore the galvanized coat is being deposited at a rapid rate. If all other plating line parameters are unchanged, a higher rate of plating deposition is indicative of a greater plating coat thickness.
In a plating line, the plating thickness should be controlled. It is one object of the present invention to provide an automated means for uniformly depositing a plating of a given thickness upon a sheet of steel or other material by control of the plating current.
Two factors other than the plating current affect the production of the proper plating thickness by the line. These factors are the speed with which the product moves within the solution and the physical dimensions of the product material (typically width). A rapidly moving, wide sheet of product material will require a greater plating current to produce a given thickness than a narrow slowly moving line of product material.
In the present invention, the plating current is chosen to be a dependent variable with the independent variables chosen to be the plating thickness, the material width, and the speed with the material moves through the plating line. The interdependence of plating current with product material speed, material width, and plating thickness is well defined so long as the number of plating electrodes remains a constant. Although only four plating electrodes are depicted in FIG. 1, a typical plating line will include many more than four plating electrodes. In one commercial line such as that disclosed in the Avellone patent there are 34 anodes. The increased number of plating electrodes does not effect the total plating current but does reduce the total plating current for each individual electrode. It is one object of the present invention, therefore, to adjust the plating potentials of each of a number of plating electrodes until those electrodes share the current equally and until the total plating current reaches an optimum value to provide the correct coating thickness.
To achieve a sharing of the plating current among a plurality of plating electrodes, it is necessary that each of the plating rectifiers be maintained at an electrical potential which will produce a plating current which is an appropriate share of the total of all electrode plating currents. The value of the proper plating potential to provide the correct plating current may vary from one electrode to the next. Thus, although the plating electrodes of FIG. 1 are shown connected to one plating potential source 26, it should be appreciated that each individual electrode is energized by an individually adjustable plating rectifier controller (shown in FIG. 5).
The plating control system embodied by the present invention comprises a control or reference signal generator 112, a first feedback circuit 114, and a plurality of secondary feedback circuits 116. The control signal generator provides a control or reference signal 118 to the first feedback circuit. This signal 118 is functionally dependent upon the speed with which the plating line moves, the width of the plating material, the thickness of the desired plating coating, and the number of operating rectifiers sending current to the plating electrodes. This control signal is proportional to the optimum plating current which the totality of the plating rectifier should produce.
In those instances in which the system is not producing enough circuit or in which the system in over producing, the control signal is modified by the first feedback circuit 114. The first feedback circuit receives an input 119 from each of the plurality of secondary feedback circuits. Each of these inputs is proportional to the actual, measured plating current in an associate one of the plating rectifiers. The inputs are summed in a total current amplifier 120 which produces a total actual current signal 122. This signal is sent to a comparator amplifier 130 where its magnitude is compared with the control signal 118 from the control or reference signal generator.
The comparison between the control signal 118 and the total current signal 122 determines how the control signal is to be modified by the first feedback circuit 114. This comparison can produce three possible results. It is conceivable that the plurality of individual plating rectifiers are producing a current which adds to a total plating current precisely correct for the particular plating thickness, width and line speed. If this situation exists, the comparison by the comparator 130 will produce no output signal and no modification is made in the control signal 118.
In the beginning of the plating operation, two other results are more likely to occur. The plating rectifiers are probably either over or under producing. In this non-optimum situation an output 124 from the comparator 130 will produce a signal which is either positive or negative depending on whether the rectifier units are over or under producing. This output is transmitted to a summing amplifier 140 within the first feedback circuit.
The summing amplifier 140 is configured to modify the reference signal 118 from the reference signal generator in response to plating line performance. The summing amplifier 140 has two inputs 141, 142. A first input 141 is the signal from the control signal generator and the second input 142 is the signal from the comparator amplifier 130. As noted previously, if the system happens to be operating correctly and the total plating current is the required value, the input from the first comparator 130 will be 0 volts. In this instance the summing amplifier will leave the other input 141 from the control signal generator unchanged. When a discrepancy occurs between the actual currents and the optimum, the signal from the reference or control generator 141 is modified in order that one or more modified reference signals 144 can be sent to the plurality of secondary feedback circuits 116 so that they may modify the outputs from the plating rectifiers.
The modified control or reference signal 144 is sent to a multi-plexing junction 150 where it is transmitted to each of a number of secondary feedback circuits 16. The multi-plexing junction sends identical signals to each of the secondary feedback circuits in order that the plating rectifiers in each of the plating rectifier circuits are instructed to operate with the same current output.
The secondary feedback circuits 116 control the apportioning of the plating current among the operative plating electrodes 20. The secondary feedback circuits comprise a secondary feedback summing amplifiers 170, a rectifier controller 180, and a current amplifier 190. The summing amplifier has an input 171 from the first or primary feedback circuit and an input 172 from the current amplifier 190. The latter input is directly proportional to the actual current in the electrode associated with the particular secondary feedback circuit. As seen in FIG. 2, the output 191 from the circuit amplifier 190 is also transmitted to the first or primary feedback circuit 114. In this way an input is provided to a total current amplifier 120. That amplifier 120 receives inputs from other current amplifiers 190 in other secondary feedback circuits and provides information concerning the total plating current output to the comparator amplifier 130.
The summing amplifier 170 which comprises a portion of the secondary feedback circuit compares the magnitude of its two inputs and produces an output signal 256 in response to the comparison. This output signal 256 controls the operation of the rectifier controller 180. This rectifier controller in turn determines the voltage appearing at a plating rectifier which is connected to an associated electrode 20. A high input voltage on the rectifier will produce a higher current within the electrode than a low input voltage. Thus, if the particular plating electrode controlled by the secondary feedback circuit is under-producing, the output 256 from the amplifier 170 will cause the rectifier controller 180 to increase the rectifier voltage. If the rectifier is already producing more than enough current, the rectifier 180 will be instructed by the comparator 170 to cut back on its voltage. If the plating rectifier is already producing an optimum current, the output 172 will instruct the plating rectifier controller 180 to maintain the voltage on that rectifier.
The interaction between the first and secondary feedback circuits causes optimum plating current production and a sharing of the plating load among the number of plating rectifiers within the system. The utilization of the two amplifiers 130, 170 insures that not only the total plating current will provide the proper plating thickness, but that each of the individual plating rectifiers is within its operating limits, producing a current equal to the other plating rectifiers.
The functioning of the first and secondary feedback circuits depicted in simplified schematic form in FIG. 2 illustrates some of the advantages and features of the system. It is possible to hypothesize a situation, for example, in which the total system current is less than an optimum value but in which one of the more efficient recifiers was producing a current which is greater than its alloted portion. In this situation, it would be advantageous for the line to produce more total current but for the efficient rectifier to cut back on its current production and allow those inefficient rectifiers to produce more current. The first and second feedback circuits of the present invention will modify current production to accomplish this feat. In the hypothesized situation in which the total current is inadequate to produce the proper plating thickness, the total current summing amplifier 120 produces a signal to the first feedback comparator amplifier 130 causing that amplifier to produce an output 124 whose magnitude is other than zero. This signal would be an input to the summing amplifier 140 which modifies the reference signal from the reference signal generator 112. This modification is then sent to each of a number of secondary feedback circuits to cause the individual plating currents to increase.
It is hypothesized, however, that one efficient plating rectifier is already producing a current in excess of the value required of it. The plating current amplifier 190 associated with that rectifier would produce an input 172 to the comparator 170 indicating this fact. When the signal from the first feedback circuit is compared to the comparator's other input, a signal is produced causing the rectifier controller 180 to decrease the current produced by the efficiently operating plating rectifier. If all other rectifiers are under producing, the signal from the first feedback circuit 114 causes their associated summing amplifiers 170 to increase the voltage on the plating rectifiers and thereby increase the current through the inefficiently operating electrodes.
This example illustrates how the analog electronics of the present invention through a trial and error process which continues as the plating line is operating will produce an optimum plating situation. All plating rectifiers will produce an equal current and this current will add to a total plating current which will provide the optimum plating thickness for the operating characteristics of the plating line.
A detailed schematic for the present control system 10 is illustrated in FIGS. 3, 4 and 5. It should be appreciated that while many of the individual component values have been included in these diagrams, other combinations of components could be utilized in the control system to achieve the improved performance characteristics. As seen in the figures, a number of operational amplifiers are included. It is known that these amplifiers require positive and negative energy inputs as well as trimming resistors. These inputs to the amplifiers have been illustrated for a tachometer amplifier 210 within the reference signal generator 112 but have been omitted from all other system operational amplifiers.
The reference or control signal generator 112 includes an input 218 from a tachometer (not shown). This input receives a voltage signal which varies directly with the speed the drive rollers 16 cause the material to pass through the plating vat. The faster they traverse through the vat, the higher the output voltage created by the tachometer.
The generator 112 further comprises a reostat arrangement 212, an operational amplifier 210, and an inoperative rectifier switch 214. These elements in conjunction with the signal from the tachometer provide a signal which is functionally dependent upon the speed of the motion through the plating vat, the physical width of the plating material, the proper thickness of the coating, and the number of operative rectifiers within the plating system. By altering the position of the inoperative rectifier switch 214 and the tapped resistor arrangement 212, the operator may adjust the optimum signal from the reference generator to correspond to the physical dimensions and operating parameters of the system. These elements in combination obviate the need for a complex or difficult to understand plating chart which causes difficulties in prior art plating systems.
The manual programming arrangement includes two multi-turn reostats 220, 222 for accessing a portion of the signal from the tachometer. These two reostats are variable or adjustable and allow the operator to access a portion of the tachometer signal which can be varied according to the width of the material to be plated and the thickness of the plating coat. In one embodiment of the invention, the first reostat 220 is adjustable depending upon the thickness of the plating coat. For a thick plating coat, the signal sent to the primary feedback circuit should be larger and therefore the operator adjusts the variable reostat 220 accordingly. The second variable reostat 222 is varied according to the width dimension of the material to be coated. For materials of wider dimensions, it is desirable that more plating current be sent from the plating rectifiers and therefore the second variable reostat 222 should be adjusted to send a larger portion of the tachometer signal to the remaining circuitry comprising the system.
An important feature of the arrangement is the manual programming of coating weight and strip width by the user. Each reostat 220, 222 is mechanically connected to a control dial which is calibrated in units of either strip width or coating thickness. The system operator dials in the correct values for these variables and the reostats are automatically adjusted to provide a control signal proportional to the proper width and coating thickness.
Once the tachometer signal has been adjusted according to plating thickness and material width dimensions, that signal is input into the noninverting input of an amplifier 210. This amplifier may conveniently be a Zeltex model ZEL-1. As noted previously, the amplifier has trimming resistors and a positive and negative input for receiving energy. The output from the amplifier 210 is controlled by the inoperative switch 214. The amplifier and switch working in conjunction determine the size of the input signals to two amplifiers 130, 140 in the primary feedback circuit. When all plating rectifiers are operating, the signals to these two amplifiers are identical. When one or more of the plating rectifiers within the system are inoperative, however, the inoperative rectifier switch is switched from a first position in which the signals to the two amplifiers are identical to a second, third, fourth, fifth or sixth positions in which the signal sent to the summing amplifier 140 is greater than the signal sent to the comparator amplifier 130. This indicates that even though the total current produced should remain the same, each operating rectifier will be asked to produce more current by the primary feedback circuit 114. Switching the inoperative rectifier switch to a different position, modifies the reference signal to the comparator 140 to achieve this purpose. As discussed hereinafter, the inoperative rectifier switch is most useful to the system in a so-called manual mode of operation.
By way of specific example, in one embodiment of the invention a reference signal of 5 volts has been chosen to cause each of 17 plating rectifiers to produce a plating current of 5,000 amperes. When all 17 plating rectifiers are operating, this amounts to a total plating current of 85,000 amperes. In a situation in which only 16 plating rectifiers, however, are functioning each of those rectifiers must produce more than 5,000 amperes if the correct plating current of 85,000 amperes is to be achieved. In that instance when one plating rectifiers is inoperative, the signal to a first comparator 130 in the first or primary feedback circuit should remain the same since the total plating current must be unchanged even when one rectifier becomes inoperative. The signal passing through the inoperative switch 238 to the second operational amplifier 140, however, must be adjusted to cause each of the plating rectifiers to produce something more than 5,000 volts. (For 16 rectifiers to produce 85,000 amperes, each rectifier must produce approximately 5,300 amperes). To produce these changes necessitated by inoperative rectifiers, a series of resistors 230 is included between the output from the tachometer amplifier 210 within the reference generator and the inoperative switch. By positioning the inoperative rectifier switch in one of the five alternate positions and by the correct choice of those resistors in the series 230, the reference signal to the summing amplifier 140 is automatically adjusted to produce the proper size signal to control plating current within each of the rectifier units. In an instance where a 5 volt signal is sent to the comparator 130 a signal of approximately 5.312 volts will be sent to the summing amplifier 140.
As seen in FIG. 3, the primary or first feedback circuit 114 includes four operational amplifiers and a number of individual discrete components. Trimming and energizing components have been omitted from these amplifier units. In the embodiment illustrated all amplifiers except the summing amplifier 140 are Zeltex model ZEL-1 amplifiers. The summing amplifier 140 is a Zeltex model ZEL-IC.
A first amplifier 120 is constructed to operate as a summing amplifier. This amplifier receives a number of outputs 254 from the current amplifiers 190 in each of the secondary feedback circuits. When each of the signals from the current amplifiers is summed in the summing amplifier, an output signal 122 is produced which is proportional to the summation of the total plating current within the line. This total plating current is displayed in a total current meter 246 and is also sent to a comparator amplifier 130. In this way a signal directly proportional to the actual plating current is available for comparison with a reference or command signal from the reference signal generator.
A buffer amplifier 242 is included within the primary feedback circuit. The buffer amplifier maintains power transfer from the inoperative rectifier switch 214 to the summing amplifier 140 and does not affect or change the size of the electrical signal passing from the former to the latter.
The primary feedback circuit further includes a manual/automatic switch 244 which is physically located near a noninverting input to the summing amplifier 140. In the automatic mode the output from the comparator amplifier 130 is sent to the summing amplifier 140. When operating in the manual mode, however, no input from the comparing amplifier 130 is sent to that amplifier and therefore no modification in the command or reference signal is made as a result of the comparison between actual and desired current levels.
In the manual mode all rectifiers are programmed to produce identical currents but the total plating current may not be correct because the summing amplifiers 120, 130 do not modify the reference signal. The manual mode is used, for example, if the strip to be plated has wavy edges which cause electrical "short circuits" in the plating tanks when the strip touches the plating anodes. By disabling the feedback signals, these electrical disturbances are not transferred to the rectifier units. It is when no feedback signal is controlling the system (i.e., when the switch 244 is in the manual position) that the inoperative rectifier switch is required. When the system operates in the automatic mode the inoperative rectifier switch has little or no effect since errors in plating current are compensated for by the action of the amplifiers 120, 130.
When operating in the automatic mode, an output 124 from the comparator amplifier 130 is directly added to the output from the buffer amplifier 242. If the output from the comparator is zero, the total current is correct for the physical parameters necessary for correct plating and no modification or change is made in the command or reference signal 118 from the buffer amplifier 242. If a non-zero output from the comparator amplifier 130 occurs, this signal is algebraically added to the command or reference signal to cause the individual plating rectifiers to produce a current other than they are presently producing. This command signal is sent to each of the secondary feedback circuits from the output 250 of the summing amplifier 140.
It is constructive to examine the polarities of the signals which are sent through the first feedback circuitry 114. The tachometer output is negative with respect to ground and is directly proportional to line speed. The control generator includes a non-inverting tachometer amplifier 210, therefore, the signal emerging from that amplifier is also negative. The buffer amplifier does not inver the signal so it is apparent that the control signal occurring at the summing amplifier 140 will always be negative and will vary in size depending upon the plating speed, material width, plating thickness and the number of operative rectifiers. The polarity of the signal passing through the automatic/manual switch, however, will depend upon whether the system is overproducing or underproducing. If the combined plating currents of all rectifiers that are operating is below the optimum signal as indicated by the control or reference generator, the signal passing through the automatic/manual switch 242 will be negative and will add algebraically to produce a larger negative signal at the summing amplifier 140. If, on the other hand, the combined signal 122 indicative of total plating current is larger than the optimum control signal sent by the reference generator, the signal passing through the manual/automatic switch will be positive and will reduce the size of the output signal from the summing amplifier.
After combination in a summing junction 254, the algebraic sum of the control signal 118 and deviation signal 124 are amplified by the summing amplifier which is a gain of two amplifier. This amplifier sends a modified control signal to each of the secondary feedback circuits. In the automatic mode of operation, this modified signal will be larger than the signal from the control signal generator if the combined rectifiers currents are less than the optimum current signal provided by the control signal generator. The modified signal will be smaller than the control signal generator signal if the rectifiers are producing more current than the optimum signal required by the control signal generator. From the above, it is apparent that the first feedback circuit operates to compare the actual current in the plating rectifiers with the calculated optimum current as produced by the control signal generator. A control signal dependent on the results of this comparison is then sent to each of the individual plating rectifier circuits.
The primary feedback circuit is comprised of analog electronics which provides continuous control of the system's operation. This electronics is less susceptible to transients commonly encountered in an industrial environment. Since the control employs feedback methods, a delay period is introduced in the feedback to allow the plurality of secondary feedback circuits time to respond to the modified command signal. The delay is achieved via a 8 uf capacitor which in conjunction with a 400 kilohm resistor slows down the signal passing through the comparator amplifier 130. This delay gives the secondary feedback circuits time to react to the control signal before that control signal is modified by the output of the comparator 130.
Each of the secondary feedback circuits 116 (See FIG. 4) comprises an input 250, a summing amplifier 170, a current amplifier 190, a current limiter 236, and a first 254 and second 256 outputs. The input signal is from the first feedback circuit 114 and represents a command or reference signal to the secondary feedback circuit. This input can either be modified or unmodified depending on whether the automatic/manual switch is in the automatic or manual mode. In either configuration, the signal will directly control operation of a voltage control circuit 180 associated with the secondary feedback circuit 116. It should be appreciated that the input from the primary feedback circuits goes to a plurality of secondary feedback circuits and the circuit shown in FIG. 4 is representative of those circuits.
The current amplifier 190 provide an output 318 to the summing amplifier 170 which is proportional to the current in its associated electrode and rectifier. In the present embodiment the components controlling operation of the amplifier 190 are adjusted to maintain a voltage output of 5 volts for every 5,000 amperes in plating current from that rectifier. Any current flowing within the rectifier will produce a potential difference across a current shunt 362 which is transformed to positive signal at the output 318 of the amplifier 190.
In normal operation, the output from the current amplifier 190 and the input 250 from the primary feedback circuit are compared at a junction 260 at the inverting input to the summing amplifier 170. The relative size of the two inputs to this junction determine the size of the output 256 from the summing amplifier 170. This output controls the operation of the voltage control circuit 180 (See FIG. 2). The comparison of the two inputs can produce three results. One result occurs when the input from the primary feedback circuit and the input from the current amplifier 190 are identical, the output from the summing amplifier 170 will be maintained at its current value and leave unchanged the output from its associated rectifier circuit.
When the two inputs 250, 254 are unequal, however, the output from the associated rectifier circuit should be altered to produce the proper plating current. If the input from the primary feedback circuit is larger than the input from the current summing amplifier 190, the output from that rectifier circuit should be increased. If, on the other hand, the input 250 from the reference control generator is less than the signal from the current summing amplifier 190, the output from that rectifier should be decreased. As will be seen below, the voltage control device chosen in the present embodiment is only responsive to positive going signals. For this reason the descrete components associated with the summing amplifier 170 have been chosen to limit the output from that amplifier to positive going signals. In particular, a diode on the feedback loop of the amplifier and a 200 ohm resistor on the input to that amplifier effectively control operation of that amplifier to coincide with the needs of the voltage control device. The 200 ohm amplifier is to unbalance the inputs to the summing amplifier 170 and the 1N270 diode insures that only positive going signals are output from the amplifier 170.
Each secondary feedback circuit further includes a current limiter 236. This limiter is designed to limit current through its associated rectifier circuit (see FIG. 5) to a maximum value. In this way, a constraint can be placed upon the system operator which allows him to produce a current up to a maximum value but will not allow him to extend the production capabilities of the line rectifiers beyond their rated capabilities. The current limiter has an input from the current amplifier 190 and an output which is connected to the inverting input of the summing amplifier 170. In the present embodiment the current limiter 236 is constructed to limit current within the plating rectifier to 5,000 amperes. It could conveniently be adjusted or modified to limit the current to some value other than 5,000 amperes.
The current limiter 314 includes a transistor 340 which is turned on and off in response to the output 254 from the current amplifier 190. Operation of the current limiter can best be understood by way of example. Consider an example in which the system operator has asked for too much current from the rectifiers by seeking to achieve a 6,000 ampere output from each rectifier. The current output from the rectifier will gradually rise until it reaches its maximum safe output of 5,000 amperes. This rise in current will be achieved through operation of the voltage control device which will be explained in detail below. As the current from the rectifier rises, the output from its associated current amplifier 190 will also rise until when the current is equal to 5,000 amperes, the output from that amplifier will then be approximately 5 volts. If the current limiter were not inserted within the circuit, the current within each individual rectifier would continue to rise until a 6,000 ampere output were achieved. This output would then stabilize operation of the summing amplifier 170 to produce a stable condition within the voltage control device.
When the output from the current amplifier 190 reaches 5 volts, however, the current limiter 236 is activated and directly controls operation of the summing amplifier 170. The current limiter causes the summing amplifier 170 to respond to the output from the rectifier as though that output is larger than it actually is. In this way the large input signal 250 from the primary feedback circuit is counterbalanced by the actual input 254 from the summing amplifier and a new input 320 from the current limiter.
As the output from the current amplifier 190 rises above 5 volts, a Zener diode 342 in the current limiter circuit allows current to flow through a 5 kilohm resistor. As the current flows through that resistor a voltage drop occurs across the resistor biasing the transistor 340 into a conducting state. When the transistor conducts, a voltage appears at the emitter of that transistor. This voltage adds to the voltage already appearing at the summing amplifier inverting input causing the summing amplifier to sum the algebraic total of its three inputs. The input from the current amplifier 190 adds to the input from the current limiter 236 to exceed the input 250 from the primary feedback circuit. When this occurs, the output from the summing amplifier 170 causes the voltage control device to reduce the current through the rectifier circuit. When this occurs the current limiter again becomes inoperative and its input 320 to the summing amplifier 170 goes to zero. In this way the current limiter 236 limits the output from its associated rectifier circuit to a maximum value and prevents the system operator from exceeding the rated limits of that rectifier. It should be appreciated that the biasing of the transistor 340 within the current limiter could be adjusted to allow the operator to operate at a different maximum current for each rectifier and that this value could be changed if different rectifiers or different capabilities were desired.
One suitable voltage control device 180 is illustrated schematically in FIG. 5. The device receives an output signal 256 from the summing amplifier 170 and in response to that signal controls the voltage produced by a rectifier 358 attached to the electrodes suspended in the vat 12. The particular voltage control device chosen in this embodiment responds to only positive going signals. The output from the summing amplifier 170 is therefore always maintained positive with respect to ground due to operation of the diode and 200 ohm offsetting resistor shown in FIG. 4.
The voltage control device 180 responds to the summing amplifier output by increasing, decreasing, or maintaining the voltage on the plating electrode. If the input to the amplifier 170 from the primary feedback circuit is greater in magnitude than the input from the current amplifier 190, the particular rectifier under control is underproducing and therefore the voltage on that rectifier should be increased. If the primary feedback input is smaller than the current amplifier input to the summing amplifier 170, then the rectifier is producing too much current and the voltage control device 180 should lower the voltage on that rectifier. To perform its control operation, the voltage control device in one embodiment of the invention comprises an alternating current input 355, a control module 352, a saturable core reactor 350 and rectifier transformer 356 which are connected in series, and a rectifier 358. The control module 352 responds to the input from the summing circuit 170 and in response to the input modifies the current passing through the primary winding 353 of a saturable core reactor 350. The saturable core reactor is connected in series with a primary windings of the rectifier transformer and the two in a series are connected across a 460 volt input of alternating current. Since the primary windings of the rectifier transformer present a constant resistance to the alternating current source, changes in the impedance of the saturable core reactor secondary windings 354 change the voltages across the rectifier transformer.
The signals sent to the saturable core reactor from the control module changes the impedance of the secondary windings 354 in the saturable core reactor. This phenomena is best illustrated by way of an example. When the control module sends no direct current through the primary windings of the saturable core reactor, the reactor presents a high impedance to the source. When this occurs most of the input voltage from the source drops across the secondary 354 of the saturable core reactor 350. If 460 volts are provided by the source 355 and no current flows to the primary windings of the saturable core reactor, then approximately 430 volts will drop across that reactor and 30 volts will drop across the primary transformer 356. Through transformer action this 30 volt drop across the primary is converted to a 2.5 volt alternating current across the secondary. When this small voltage is rectified by the rectifier 358, a very small current is produced in the associated electrode with the result that very little plating current is supplied.
To increase the voltage on the plating electrode, it is necessary for the control module 352 to send a fairly large direct current through the primary windings 353 of the saturable core reactor. In this instance the impedance of the reactor drops in relations to the 460 volt input and most of the voltage drop will appear across the primary windings of the rectifier transformer. When a maximum current flows through the primary of the saturable core reactor, only 30 volts of the 460 volt total drop appears across the reactor, the remaining 430 volts appear across the primary of the transformer. The transformer action produces an output of approximately 17 volts which is rectified and sent to the plating electrode. Thus, by changing the current to the primary of the saturable core reactor the control module can alter the voltage appearing at the plating electrode and thereby change the current produced by the particular electrode under control.
The direct current in the primary of the saturable core reactor can be varied continuously from a maximum to a minimum value. The control module responds to input signals from the summing amplifier 170 to produce a current flow in the primary in the saturable core reactor. Various designs might be chosen for the control module so long as an appropriate continuously variable d.c. signal can be provided in response to the output 256 from the summing amplifiers 170. Each electrode in the plating line has its own voltage control device with associated saturable core reactor. Thus, in a system utilizing 34 plating electrodes there will be 34 saturable core reactors and plating rectifier circuits.
Certain components have been included within the plating control system for adding convenience in operation and facilitating system maintenance. A total current meter and as well as a total current deviation meter have been included in the primary feedback circuit (See FIG. 3) to enable the operator to insure that input parameters dialed into the reference or control signal generator produce the proper total current. If they do not, the total current deviation meter will yield a non-zero value. As seen in FIG. 4, each of the secondary feedback circuits includes a setup/run switch 212 which during normal operation of the system is switched to the run configuration. In the setup configuration, however, the switch enables the system operator to access a calibration signal which allows him to fine tune the summing amplifier 170. This switch enables the operator to properly adjust and calibrate the secondary feedback circuits without interrupting plating line operations.
From the above it should be obvious to one skilled in the art that certain modifications in the discrete components of the present system could be made without departing from the scope of the invention. In particular, different operational amplifiers might be chosen to produce similar results and it is possible that design modifications could be made in the voltage control device for producing a voltage to the plating rectifier. Thus, while the present invention has been described with particularity, it should be understood to one skilled in the art that various modifications and design alterations might be made therein without departing from the spirit or the scope of the invention as set forth in the appended claims.
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An automatic plating current control system for an electroplating line. The plating line includes a plurality of power circuits, each including a rectifier and an electrode, for delivering plating current to affect electrodeposition on the workpiece surface.
The automatic control system includes a reference generator, a first feedback circuit for controlling the total plating current applied by all the power circuits and a plurality of second feedback circuits each associated with a different power circuit. Each of the second feedback circuits co-operates with the first feedback circuit for regulating plating current output of the individual power circuits to apportion the current output among the operative power circuits. The reference generator produces a reference signal representing a desired plating current in response to information input to the reference generator, specifying workpiece speed, workpiece dimension and desired plating thickness.
Each power circuit includes an output voltage control and a current metering circuit. The voltage control circuitry is provided for each power circuit to limit its plating current output to a predetermined maximum without disabling the power circuit. Compensation circuitry is provided for altering the reference signal for varying the fraction of plating current apportioned to each power circuit to compensate for inoperability of one or more power circuits.
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TECHNICAL FIELD
This disclosure relates generally to printheads for inkjet printers, and more particularly, to systems and methods for the control of the size and location of air bubbles that form in a liquid path for ink in a printhead.
BACKGROUND
Air bubbles in ink flow paths of inkjet printers can impact the performance of the printers. In printers that use solid ink, air bubbles are formed during the freezing and melting of the solidified ink. Typically, when a solid inkjet printer is not operating, melted ink in the ink flow paths solidifies.
FIG. 3A is a cross-sectional view of fluid paths, a pressure chamber, and air vents in a prior art inkjet in a printhead 500 , and FIG. 3B is a top plan view of an exemplary nozzle plate 550 in a printhead that includes the inkjet of FIG. 3A . The exemplary print head 500 is configured for use in an inkjet printer. While FIG. 3A and FIG. 3B depict a single inkjet for illustrative purposes, existing printhead embodiments include multiple inkjets, including arrays of hundreds or thousands of inkjets in some embodiments.
In FIG. 3A , the printhead 500 includes a substrate 520 , a silicon wafer 530 on an upper surface of the substrate 520 , an ink passage 540 through the substrate 520 and silicon wafer 530 , a tube 545 connecting the ink passage 540 of the print head 500 to an ink supply reservoir, and a nozzle plate 550 mounted on the structure. An electrostatically actuated membrane 560 is formed on the silicon wafer 530 as shown. A pressure chamber 565 receives liquid ink through the fluid ink passage 540 . A nozzle hole 570 and a matrix of purge vents 590 ( FIG. 3B ) can be formed in the nozzle plate 550 . The purge vents 590 in FIG. 3A and FIG. 3B are formed as a group of small nozzle holes formed through the nozzle plate 550 . Air enters and leaves the pressure chamber 565 during operation of the print head 500 through the group of purge vents 590 . The purge vents 590 are large enough to enable air to escape from the pressure chamber 565 as ink fills the pressure chamber, and to admit air when liquid ink in the pressure chamber solidifies in embodiments of the printhead 500 that use a phase-change ink.
In the print head 500 , the membrane 560 is an electrostatically actuated diaphragm, in which the membrane 560 is controlled by an electrode 562 . The membrane 560 can be made from a structural material such as, for example, polysilicon, as is typically used in a surface micromachining process. An air vent 564 between membrane 560 and wafer 530 can be formed using typical techniques, such as by surface micromachining. The electrode 562 acts as a counterelectrode and is typically either a metal or a doped semiconductor material, such as polysilicon. Alternative inkjet embodiments include a piezoelectric actuator or a thermal actuator.
During operation of an electrostatic or piezoelectric actuator, the electrode 562 receives an electrical signal and the membrane 564 deflects into the pressure chamber 565 . The deformation generates pressure on the ink in the pressure chamber 565 and the pressure urges an ink drop, such as the ink drop 582 , through the nozzle 570 . In some configurations, the membrane 560 deflects toward the electrode 562 prior to deflection into the pressure chamber 565 to draw ink into the pressure chamber 565 for ejection through the nozzle 570 . In a thermal inkjet, the electrical signal generates heat in the pressure chamber and the heat produces an air bubble that urges ink in the pressure chamber 565 through the nozzle 570 to eject an ink drop in a similar manner to the arrangement of FIG. 3A .
The purge vents 590 in the nozzle plate 550 have diameters that are typically smaller than the diameter of the nozzle 570 , and are sufficiently narrow to prevent ink from passing through the nozzle plate 550 at a location other than the nozzle 570 during operation of the printhead 500 . During operation, a meniscus of liquid ink forms across the opening to each of the purge vents 590 from the nozzle plate 550 to the pressure chamber 565 . The strength of the meniscus enables ink to remain in the pressure chamber 565 and to be ejected through the nozzle 570 without being ejected or otherwise leaking through the purge vents 590 . In one embodiment, each of the purge vents 590 is formed with a diameter of approximately 3 to 5 microns. In comparison, the diameter of the nozzle 570 is approximately 27.5 microns in the embodiment of FIG. 3A . The small size of the purge vents 590 minimizes the impact of the vents on the flow of liquid ink to the inkjet, which enables the ink to flow to the pressure chamber 565 with sufficient liquid pressure to supply the inkjet with ink during printing operations.
In the prior art embodiment, the vents 590 enable air bubbles to escape from liquid ink in the fluid path 540 and pressure chamber 565 . Some air bubble, however, may be formed in portions of the printhead where the air bubbles are unable to be vented easily. For example, in the printhead 500 an air bubble that forms near the nozzle 570 does not escape through the vents 590 , but instead escapes through the nozzle 570 where the air bubble disrupts the process of ejecting ink drops. Additionally, while small air bubbles that form near the vents 590 can escape from the printhead 500 , larger air bubbles formed within the channel 540 and the pressure chamber 565 can interrupt the flow of ink to the pressure chamber 565 for a longer period of time before escaping from the printhead 500 . What is needed is a printhead design that mitigates the formation of air bubbles in locations that are difficult to purge, and mitigates the formation of large air bubbles.
SUMMARY
An inkjet printhead has been developed that facilitates the removal of air bubbles from ink flow paths in a printhead and helps reduce the size of air bubbles formed in the ink flow paths. The inkjet printhead includes a member having a channel through the member with a first opening and a second opening to enable melted ink to enter the channel at the first opening and flow through the channel to the second opening, and at least one protrusion extending from the member to position a portion of the protrusion into melted ink in the channel to form a dominant stress concentration in the melted ink.
A method of making an inkjet printhead has been developed that facilitates the removal of air bubbles from ink flow paths in a printhead and helps reduce the size of air bubbles formed in the ink flow paths. The method includes providing a vent in a member having a channel with a first opening and a second opening to enable melted ink to enter the channel at the first opening and flow through the channel to the second opening, and providing at least one protrusion extending from the member into the channel to position a portion of the protrusion into melted ink in the channel to establish a dominant stress concentration in the melted ink for forming air bubbles at a predetermined location in the channel.
The inkjet printhead and method can be used in an inkjet printer to facilitate the removal of air bubbles from ink flow paths in a printhead and help reduce the size of air bubbles formed in the ink flow paths. The inkjet printer includes a printhead having a body, a reservoir, a channel within the printhead body that is fluidly connected to the reservoir, the channel having a first opening and a second opening to enable melted ink to enter the channel at the first opening and flow through the channel to the second opening, and at least one protrusion extending from the printhead body into the channel to position a portion of the protrusion into melted ink in the channel to enable air bubble formation at the protrusion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A depicts a fluid path for use in a printhead that includes protrusions to control the formation of air bubbles within the fluid path when the fluid path is filled with a liquid ink.
FIG. 1B depicts the fluid path of FIG. 1A when the fluid path contains solidified ink.
FIG. 1C depicts the fluid path of FIG. 1A and FIG. 1B after solidified ink in the fluid path returns to a liquefied state.
FIG. 2A depicts another fluid path for use in a printhead that includes a protrusion to control the formation of air bubbles within the fluid path when the fluid path is filled with a liquid ink.
FIG. 2B depicts the fluid path of FIG. 2A when the fluid path contains solidified ink.
FIG. 2C depict the fluid path of FIG. 2A and FIG. 2B after solidified ink in the fluid path returns to a liquefied state.
FIG. 3A depicts a cross-sectional view of a prior art inkjet in a prior art printhead.
FIG. 3B depicts a plan view of a prior art nozzle plate in the printhead of FIG. 3A .
DETAILED DESCRIPTION
Protrusions can be arranged in a printhead flow path to mitigate the formation of large air bubbles that are difficult to remove. FIG. 1A-FIG . 1 C depict a printhead channel 300 within a member or body of the printhead that enables ink to flow through the printhead and a plurality of protrusions formed in the channel to control the locations of bubble formation within the channel 300 . Referring to FIG. 1A , the printhead channel 300 provides a flow path 304 . The flow path 304 has two opposite ends 306 and 308 . The flow path 304 is filled completely with melted solid ink 310 , which flows from the end 306 to the end 308 during normal operation. However, unlike the pressure chamber 565 in FIG. 3A , the printhead channel 300 includes protrusions 312 . The protrusions 312 are arranged along the wall 302 , and extend from the wall 302 into the flow path 304 and, accordingly, into the solid ink 310 . The protrusions 312 modify the nominal stress concentrations as the melted solid ink 310 solidifies by establishing dominant stress concentrations at each of the protrusions 312 . As used in this document, the term “dominant stress concentration” refers to a local maximum in the average force per unit area that particles of a body exert on adjacent particles of the body. The dominant stress concentrations promote the cracking of the solid ink 310 at their locations when the solid ink 310 solidifies. The dotted lines represent the expected cracking points in the solid ink 310 as the ink shrinks during cooling and freezing. FIG. 1B depicts the printhead channel 300 of FIG. 1A in which the solid ink 310 has cooled and solidified within the flow path 304 . As the solid ink 310 solidifies, cracks form in the solid ink and voids 314 are formed in the solid ink. However, the dominant stress concentrations at the protrusions 312 enable the voids 314 to form in a predictable and distributed manner. FIG. 2 c depicts the printhead channel 300 of FIG. 2 b in which the solidified solid ink 310 has been warmed to a temperature that enables the solidified solid ink to melt within the flow path 304 . The voids 314 have turned into air bubbles 316 . The air bubbles 316 are small and are distributed across the length of the flow path 304 , thereby enabling the air bubbles 316 to be removed from the flow path 304 with less ink purged from the path. In this way, protrusions can be strategically arranged within a printhead flow path for the purpose of mitigating the formation of large and difficult to remove air bubbles. Smaller air bubbles can be forced out of the purge vents with less ink flow than larger air bubbles, reducing waste. Protrusions can be any of a variety of shapes such as conical, spherical, cylindrical, rectangular, and the like. The shapes and sizes of the protrusions are governed by the geometry of the channel, ambient conditions surrounding the printhead, processes for warming and cooling the printhead, active and passive thermal gradients, imposed pressure gradients, ink properties and the like.
In addition to controlling the size of air bubble formation, protrusions can also be strategically arranged to control the location of air bubble formation. FIG. 2A-FIG . 2 C depict a printhead channel 400 within a member or body that defines a flow path 404 for ink. The flow path 404 has two opposite ends 406 and 408 . The flow path 404 is completely filled with melted solid ink 410 , which flows from the end 406 to the end 408 during normal operation. The flow path 404 has a narrow region 412 . Purge vents 414 are arranged along the wall 402 near the end 408 and downstream of the narrow region 412 . The narrow region 412 can cause the melted solid ink 410 to crack in the narrow region 412 as the ink solidifies. The printhead channel 400 includes a protrusion 416 , which is positioned on the wall 402 near the narrow region 412 and substantially opposite the purge vents 414 . The protrusion 416 extends into the flow path 404 to establish a dominant stress concentration near the narrow region 412 but angled slightly toward the end 408 and the purge vents 414 . The dotted line represents the expected cracking point in the solid ink 410 as the ink shrinks during cooling and freezing.
FIG. 2B depicts the printhead channel 400 of FIG. 2A , wherein the solid ink 410 has cooled and solidified within the flow path 404 . As the ink 410 cools and solidifies, the volume of the ink contracts and shrinks compared to the volume of the equivalent mass of ink in the liquid state. The shrinkage of the ink during the transition from the liquid state to the solid state of the ink 410 produces cracks and voids, such as the void 418 . However, the dominant stress concentration established by the protrusion 416 near the narrow region 412 angles the void 418 slightly toward the end 408 and the purge vents 414 . FIG. 2C depicts the printhead channel 400 of FIG. 2B , in which the solidified solid ink 410 has been warmed to a temperature that enables the solidified ink to melt within the flow path 404 . The void 418 has turned into an air bubble 420 . However, because the void 418 was angled slightly toward the end 408 and the purge vents 414 , the air bubble 420 buoyed toward the purge vents 414 on one side of the narrow region 412 , rather than possibly migrating toward the end 406 , which does not have any purge vents. This bubble placement facilitates the removal of the bubble through the vents 414 during a purging process. Accordingly, the amount of ink required to purge the printhead channel 400 is significantly reduced over previously known printheads.
The protrusions disclosed in this document can be used to mitigate the size of air bubbles formed during a solidifying/melting cycle as well as to control the locations where air bubbles are formed. By applying these concepts to different printhead geometries, printhead designers can establish predictability in the size and locations of air bubble formation. This predictability can be exploited to optimize the size, quantity, and locations of purge vents. An efficient purge vent layout in which air bubbles are properly staged near purge vents and extraneous purge vents are removed, results in a reduction of the amount of ink lost during purges and overall ink costs. Furthermore, the predictability allows printhead geometries to be scaled without substantially altering air bubble purging strategies.
These concepts are of even greater use for complex printhead geometries that can accommodate purge vents in fewer locations than simple geometry printheads. Protrusions can be arranged to control air bubble formation in such a way as to promote the formation of air bubbles in preferable areas, such as those were purge vents can be accommodated, while mitigating the formation of air bubbles in undesirable locations, such as those that will not accommodate a purge vent.
The geometries of the printhead channels shown in FIG. 1A-FIG . 1 C and FIG. 2A-FIG . 2 C are exemplary and have been greatly simplified for the purposes of promoting an understanding of the principles of the protrusions and their placements. Although typical printhead geometries are much more complex than those shown in the exemplary figures and embodiments, the principles can be applied to any printhead geometry for strategic control of both the size and the locations of air bubble formation.
It will be appreciated that variants of the above-disclosed and other features, and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art, which are also intended to be encompassed by the following claims.
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Protrusions are positioned on the inner surfaces of a channel within a printhead body or member to control the size and location of bubble formation. An inkjet printhead includes a member having a first opening and a second opening to enable melted ink to enter the channel at the first opening and flow through the channel to the second opening. At least one protrusion extends from the member into the channel to position a portion of the protrusion into melted ink in the channel to form a dominant stress concentration in the melted ink.
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BACKGROUND OF THE INVENTION
The present invention is based on the problem of creating a directional drilling tool that improves directional drilling behavior and increases drilling progress.
BRIEF DESCRIPTION OF THE INVENTION
The design disclosed herein of a drilling tool with an impact device acting on its bit shaft allows for a drilling operation with a much reduced static compressive force on the drill bit which results in correspondingly reduced lateral force components on the drill bit which, in an ordinary design, act as interference forces on the desired directional behavior of the drilling tool. The smaller deflections of the drilling tool due to the reduced lateral forces are compensatable with lower radial control forces and the reduction in deviations combined with the reductions in the control forces increase the efficiency of the rock destruction process at the drill bit and allow for considerable increases in the rate of drilling progress. The drilling tool disclosed herein can be used with particularly favorable results in hard or brittle rock and in soil conditions with layers unfavorable to direction control.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows one embodiment of the present invention in a cut-away, partially broken off side view;
FIG. 2 shows another embodiment of the present invention in a cut-away, partially broken off side view.
DETAILED DESCRIPTION OF THE INVENTION
The drilling tool disclosed herein and illustrated schematically in FIG. 1 is shown in drill hole 1 and is connectable at its upper end via connectors, e.g., screw threads (not shown), to a drill string 2 and comprises a torsion resistant tool housing having an upper housing unit 3 that is provided at its lower region with stabilizer fins 4 and a lower housing unit 5 whose upper region is provided with stabilizer fins 6 and whose lower region is provided with four energizers 7 designed as lateral pressure elements capable of moving radially inwardly and outwardly. When in contact with the wall of the drill hole 1, energizers 7 determine the alignment of the drilling tool and thus the heading of the drill bit 10 and the eventual drill hole.
The drilling tool also comprises a bit shaft 8, rotatably mounted in the upper housing unit 3, rotatably extending through the lower housing unit 5, and bearing a drill bit 10 on its lower end 9 protruding from the lower housing unit 5. The bit shaft 8 is designed as a hollow shaft which surrounds a central, longitudinal channel 11 that forms a continuation of the interior of the drill string 2 and that ends at an opening in the region of the drill bit 10. An impact device or hammer assembly 12 is included as a component of the bit shaft 8 between the upper and lower housing unit 3 and 5, respectively.
The impact device or hammer assembly 12 can have any known or suitable design driven by means of the drilling fluid to generate axial vibrational forces in the lower unit 13 of the bit shaft 8 that are superimposed on a small static axial force and impart a pressure component of a threshold characteristic upon the drill bit 10. The upper end of the bit shaft 8 is linked with a rotary drive 14 located in the upper housing unit 3 and indicated schematically in FIG. 1. The drive 14 sets the drill bit shaft 8 into a preferably slow rotation which in turn gives the drill bit 10 a rotational motion.
The lower housing unit 5, which is of a tubular design like the upper housing unit 3, includes a control device 15, schematically illustrated in FIG. 1, which includes sensors used to determine the drill hole parameters, i.e., the particular position of the boring tool and especially its inclination, a processing means to evaluate the acquired data, and a transducer unit to issue control commands to the pressure operated energizers 7, of which there are at least four distributed along the perimeter of the lower housing unit 5 positioned radially in predetermined positions. The sensing, evaluating, and transducer units are not specifically shown in FIG. 1 but are generally indicated by control device 15 and can consist of various such units well known in the drilling art.
The sensing, evaluating, and transducer units of the control device 15 can control the directional profile of the drill hole 1 according to a specified program and can be equipped with a separate power source (not shown). Nevertheless, they can also be linked to an above-ground controller (not shown) via a connector cable 16 for a continual data exchange as shown in FIGS. 1 and 2. A power supply to the control device 15 can be provided via the connector cable 16 which should generally run inside the drill string 2 and then, for at least a part of its length, in the annulus of the hole 1 drilled by the drilling tool.
Compressed air is preferred as the drilling fluid or agent for the drilling tool disclosed herein, especially for drilling in mining or in construction where, frequently, depths of only a few hundred meters are needed. Use of compressed air as the drilling fluid also improves removal of fines in hard formations. Furthermore, when compressed air is used as the drilling fluid, other electrical transmission elements can be used, e.g., slip ring transferors or transformational couplings (not shown) in place of the connector cable 16. When a liquid drilling fluid is used, however, information is obtained from sequential pressure changes in the drilling fluid column, as is common in deep drilling. The design of the overall system operated by the drilling fluid, such as the specific rotary drive and impact device, is generally tailored to the particular drilling fluid used.
FIG. 2 illustrates a design of the invention disclosed herein where a shock absorber 17 acts upon the bit shaft 8 above the impact device 12. This shock absorber 17 is a component of the bit shaft 8 and is located in the region between the housing units 3 and 5, where the impact device 12 is located in FIG. 1. The impact device 12 of FIG. 2 is located in the region of the bit shaft 8, where the housing unit 5 is located in FIG. 1.
Accordingly, in the embodiment shown in FIG. 2, the control device 15 is located in the lower region of the housing unit 18 and at the level of the energizers 7. This control device 15 is also linked to an above ground control unit via a connector cable 16. The shock absorber 17 braces the threaded connectors under occurring axial shock stresses so that the amplitude of the axial force vibrations can be readily increased without effecting the threaded connections (not shown) or the components of the measuring and evaluation units of the control device 15. This, in turn, allows for an increase in the drilling rate.
In the foregoing specifications, this invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings included herein are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.
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The present invention discloses a drilling tool apparatus and method for sinking drill holes in underground rock formations while using a selectable direction profile for the drill hole.
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RELATED APPLICATIONS
[0001] This application is a Continuation-In-Part Application based on U.S. patent application Ser. No. 10/933,291 filed Sep. 3, 2004 and U.S. patent application Ser. No. 10/936,512 filed Sep. 9, 2004.
[0002] This application claims priority to Japanese Patent Application No. 2006-210506 filed Aug. 2, 2006.
FIELD OF THE INVENTION
[0003] Gallium nitride (GaN) type blue/violet semiconductor lasers will be used for reading-out data of the next generation large capacity photodiscs. Putting GaN type blue/violet laser diodes (LDs) into practice requires gallium nitride crystal substrates of high quality. This invention relates to a method of growing a high quality gallium nitride crystal (GaN) for substrate wafers on which blue/violet LDs are made. In addition to production of GaN blue/violet LDs, the GaN substrate wafers will be useful for producing light emitting devices (light emitting diodes LEDs, laser diodes LDs of other colors), electronics devices (rectifiers, bipolar transistors, field effect transistors FETs, high electron mobility transistors HEMTs, and so on), semiconductor sensors (thermometers, pressure sensors, radioactive ray sensors, visible/ultraviolet photodetectors, and so on), surface acoustic wave devices SAWs, accelerator sensors, MEMS devices, piezoelectric oscillators, resonators, piezoelectric actuators, and so on.
BACKGROUND OF THE INVENTION
[0004] GaN type laser diodes emitting 405 nm wavelength light will be used for reading-out of data of high density photodiscs. Blue/violet LEDs (light emitting diodes) are made by piling GaN, InGaN, etc., films on sapphire (Al 2 O 3 ) substrates. Sapphire is different from gallium nitride (GaN) in lattice constant. The difference of the lattice constants generates high density of dislocations. In the case of on-sapphire GaN light emitting diodes (LEDs), low current density does not proliferated dislocations. GaN LEDs on sapphire substrates have a long lifetime. But in the case of on-sapphire GaN laser diodes (LDs), high current density will proliferate dislocations and rapidly degenerate on-sapphire GaN LDs. Sapphire substrates are unsuitable for GaN LDs which have large current density. Unlike GaN LEDs, on-sapphire blue/violet GaN LDs have not been put into practice yet.
[0005] There is no material which has a lattice constant sufficiently close to gallium nitride (GaN). It turns out that the best substrate on which GaN films are grown without misfit is a GaN substrate. Realization of GaN blue/violet LDs requires low dislocation density GaN substrates with high quality.
[0006] However, crystal growth of GaN in liquid phase is difficult. Heating GaN solid does not make a GaN melt. A flux method which grows GaN solid in liquid phase is yet on the stage of research. No practical size GaN crystals with a diameter larger than 2 inches have been produced by liquid phase growth. Vapor phase growth which grows GaN crystal from vapor phase has been tried for producing high quality GaN substrate crystals having sizes enough to satisfy practical use.
[0007] The inventors of the present invention have contrived and proposed methods of making a thick freestanding GaN substrate crystal by forming masks on a foreign material undersubstrate, growing a thick GaN crystal on the masked foreign material undersubstrate in vapor phase and removing the undersubstrate.
[0008] (1) WO99/23693 of the present inventors proposed a method of producing a freestanding GaN substrate crystal by forming a stripemask with stripe windows or a dotmask with dot windows on a GaAs undersubstrate, growing a thick GaN crystal on the masked GaAs undersubstrate and removing the GaAs undersubstrate. This masks have wider masked parts and narrower exposed parts (windows). The masks are masked part prevalent masks. GaN nuclei happen only in exposed parts (windows) on the undersubstrate. The mask prevents GaN nuclei from happening. When the nuclei dilate into unified GaN grains on the GaAs undersubstrate in the windows, the GaN grains overstep on masks. The GaN grains grow in horizontal directions on masks. Movements of dislocations accompany the growth. In parallel with the growing direction, dislocations extend in the horizontal directions on masks. GaN crystals expanding from neighboring windows collide with each other at the middles between two neighboring windows on masks. Dislocations collide at the same time. Then the growing direction of GaN turns upward. Accompanying the growth, dislocations also begin to expand upward. The turn decreases dislocations. Two changes of directions decreased the number of dislocations in the ELO method. Afterward the ELO grows the crystal in the vertical direction with maintaining the flat C-plane surface.
[0009] (1) WO99/23693 which decreases dislocations by growing crystals on masks in horizontal directions is an improvement of the ELO methods (Epitaxial Lateral Overgrowth). A conventional ELO method prepares a GaN film on a sapphire undersubstrate, deposits a SiO 2 film on the GaN film, forms a mask by etching small linear or dotted windows on the mask, grows GaN crystals on the GaN film exposed via windows and allows the GaN crystals to overstep on the mask. (1) WO99/23693 forms a mask directly on a GaAs undersubstrate without GaN film and grows GaN crystals on the GaAs undersubstrate exposed via the windows, which is called HELO (Hetero-Epitaxial Lateral Overgrowth) method. The GaN crystal which is made by (1) WO99/23693 has lowered dislocation density. (1) proposed a further growth of making use of the GaN crystal as a seed of growing a new thick GaN crystal thereupon. The thick GaN crystal is sliced into several GaN wafers in the direction vertical to the growing direction in (1) WO99/23693. There are an MOCVD method, an MOC method, an HVPE method and a sublimation method for vapor phase growth of GaN. (1) mentions that the HVPE method has an advantage of the fastest growing speed among the known vapor phase methods.
[0010] However the GaN crystals produced by the ELO methods or the HELO method of (1) have high density of dislocations and poor quality. Production of good devices requires good quality GaN substrates. Existence of wide low defect density regions is indispensable for GaN substrates served for mass production of devices. The Inventors of the present invention proposed a contrivance of (2) Japanese Patent Laying Open 2001-102307 for reducing dislocation density of GaN substrates.
[0011] The dislocation reduction method of (2) Japanese Patent Laying Open 2001-102307 grows a thick GaN crystal, sweeps dislocations in the GaN crystal into definite spots and decreases dislocations in other regions except the spots.
[0012] As shown in FIG. 1 ( a ), (2) Japanese Patent Laying Open 2001-102307 grows a GaN crystal by building three dimensional facet structures for example, inverse hexagonal cone pits 5 composed of facets 6 , maintaining the facet pits 5 , and not burying the facets pits 5 till the end of the growth. FIGS. 1 ( a ) and ( b ) show a part of a crystal 4 surface having an inverse hexagonal conical pit 5 . The surface of a growing GaN is not perfectly flat. The surface has pits here and there. The flat top is a C-plane 7 . GaN crystals grow upward in the direction of a c-axis on the flat top (C-plane) 7 . GaN crystals grow slantingly upward in pits composed of inclining facets. Some pits are hexagonal. Other pits are dodecagonal. In the case of a hexagonal cone, a facet meets with neighboring facets at 120 degrees. Neighboring facets 6 and 6 join at a boundary line 8 . The bottom of a pit at which the boundary lines converge is a spot at which feet of facets assemble.
[0013] A normal (line) is defined as a straight line extending in the direction vertical to an object plane. A c-axis is a normal to a C-plane. Crystals grow on a plane in the direction of a normal standing on the plane. An average growth direction is the c-axis direction on the C-plane surface. On a facet, crystal grows in a slanting direction normal to the facet. Θ is an inclination angle of a facet to the C-plane. A normal standing on the facet inclines at Θ to the c-axis. (2) does not bury the pits of facets. Non-burying of pits means anisotropic growing speeds. The top surface (C-plane) growing speed is denoted by u. The facet growing speed v is denoted by v=u cos Θ. The growing speed v of a facet is smaller than the C-plane growing speed u. Thus the facet growth means anisotropy of growing speeds.
[0014] Dislocations extend in parallel with the growing direction. The speed of extending of a dislocation is equal to the speed of growing of the facet on which the dislocation lies. Since v<u (the growing speed of facets is slower than the growing speed of the C-plane), dislocations existing on a facet move to boundary 8 with the progress of growth. Dislocations are swept on the facets. The dislocations reaching the boundaries sink along the boundary 8 to the bottom due to the slow growing speed of facets. Planar defect assemblies 10 are built below the boundaries 8 , as shown in FIG. 1 ( b ). The falling dislocations assemble at the bottom 9 of the pit. Since dislocations swept away from the facets gather at the bottom, linear defect assemblies 11 are formed at the bottoms 9 of pits.
[0015] The dislocations D which have been on facets are attracted and assembled into the planar defect assemblies 10 or linear defect assemblies 11 . Dislocations D on the facets 6 decrease. The regions below the facets 6 become low dislocation density. The other dislocations which have been on flat C-planes 7 are attracted to neighboring facets 6 . The dislocations moved from the C-planes 7 to the facets 6 also move to boundaries 8 and to the bottoms 9 by the facet growth. When facet pits 5 exist at high density, dislocations on the facets 6 or the C-planes 7 are swept into the under-boundary regions 10 or under-pit regions 11 . The dislocations which exist on other regions are reduced. The dislocation reduction effect by facets is maintained throughout the crystal growth by not burying but keeping the facet pits 5 till the end of the growth.
[0016] FIG. 2 demonstrates the dislocation reduction effect by the facet growth in a plan view of a pit on a fact growing GaN surface. When the facet is maintained, the direction of crystal growth on a facet 6 is parallel to a normal standing on the facet 6 . Dislocations also extend in the normal direction on the facet 6 . FIG. 2 clarifies that movements of dislocations are parallel to growth directions on a facet. When the directions of dislocation movement are projected on a facet 6 in the plan view, the extension directions are parallel to the direction of the inclination of the facet 6 . The dislocation soon arrives at a boundary 8 . Then the dislocation D goes inward along the boundary 8 . Inward movement means a relative slanting fall of the dislocation along the boundary 8 . In reality dislocations extend laterally or slanting upwardly. Since v<u, dislocations seem to descend along the boundaries 8 from a reference plane fixed on the growing surface. Some dislocations descending along the boundaries make planar defect assemblies hanging below the boundaries. Other dislocations are assembled at the bottoms 9 of the pits 5 . The dislocations make defect assembling bundles 11 following the bottoms 9 .
[0017] The Inventors have noticed the facet growth method having the following problems.
[0018] Problem (1): When the GaN crystal grows thicker with assembling dislocations into defect accumulating regions H, once gathered dislocations have a tendency of escaping from the defect accumulating regions at the bottoms of pits as hazy dispersion. The release of dislocations is explained by referring to FIG. 3 ( 1 ) and FIG. 3 ( 2 ). FIG. 3 ( 1 ) is a sectional view of a pit 5 of facets 6 for showing arrested dislocations D forming a linear dislocation assembling bundle 11 at the bottom 9 of the pit 5 at an early stage of the facet growth. Dislocations in the surrounding regions 4 below facets 6 and C-planes 7 are decreased. FIG. 3 ( 2 ) shows hazy dispersion 13 of once arrested dislocations D escaping from the bundle 11 . The hazy dispersion 13 signifies that the defect assembling bundle 11 has a weak, insufficient power of arresting dislocations.
[0019] Problem (2): Positions of the defect assembling bundles 11 are determined by chance. The bundles 11 happen at random. The positions of the bundles 11 cannot be predetermined. The positions of the dislocation assembling bundles are uncontrollable.
[0020] The reason of problem (2) derives from accidental occurrence of pits 5 of facets 6 and defect assembling bundles 11 . It is desirable to predetermine the positions of the defect assembling bundles 11 . The solution of Problem (1) requires to build unpenetrable barriers on the dislocation assembling bundles.
[0021] For solving the problems, the Inventors have made contrivances. The inventors had thought that the reason of hazy dispersion occurrence 13 as shown in FIG. 3 ( 2 ) originates from the fact that the center bottoms 9 of the pits 5 of facets 6 gather dislocations without annihilating or arresting dislocations.
[0022] Thus Problem (1) shall be solved by adding a dislocation annihilating/accommodating device to the defect assembling bundles. FIGS. 4 ( 1 ) and ( 2 ) show the solution of Problem (1). A plurality of isolated dot masks 23 made from a material capable of inhibiting GaN from epitaxially growing are formed in a regular repetition pattern on an undersubstrate. Exposed parts of the undersubstrate allow GaN to start crystal growth. C-plane growth having a C-plane top 27 prevails on the exposed parts. GaN crystals 24 grow on the exposed parts 21 .
[0023] However crystal growth does not start at the parts on the wide masks 23 soon. Crystal growth continues on exposed parts. Facets 26 which are slanting planes starting from verges of masks happen. Pits 25 being composed of facets and having bottoms 29 at masks 23 are produced. Without burying the pits 25 , the crystal growth continues with maintaining the facets and the facet pits till the end of growth. Dislocations are swept by facets 26 to the pit bottoms 29 . The bottoms 29 of the pits 25 coincide with the masks 23 . Dislocations swept away are gathered at the regions below the pit bottoms 29 above the masks 23 . The above-mask, below-bottom regions become defect accumulating regions H. The defect accumulating region H consists of a grain boundary K and a core S. H=S+K.
[0024] Thus (3) Japanese Patent Laying Open No. 2003-165799 produces defect accumulating regions H enclosed by grain boundaries K as a dislocation annihilation/accommodation device by forming masks 23 on an undersubstrate 21 . A mask 23 , a defect accumulating region H and a pit bottom 29 align in a vertical line in the facet-growing GaN crystal. The masks 23 determine the positions of the defect accumulating regions H and the pits 25 . The regions below the facets 26 on exposed parts become low defect density single crystal regions Z. The other region below the C-plane on exposed parts becomes a C-plane growth regions Y.
[0025] Dislocations are continually assembling into defect accumulating regions H. The defect accumulating region H has a definite volume and is enclosed by a grain boundary K. The dislocations once arrested do not escape from the defect accumulating region H due to the grain boundary K. The grain boundary K has another function of annihilating dislocations. The crystal enclosed by the grain boundary K is a core S. The core S has functions of accumulating dislocations and annihilating dislocations. It is important for (3) Japanese Patent Laying Open No. 2003-165799 to positively produce the regions H consisting of a grain boundary K and a core and gathering dislocations by masks 23 . The surface rises from the dotted line in FIG. 4 ( 1 ) to the solid line of FIG. 4 ( 2 ). Dislocations are firmly arrested in the defect accumulating region H. Dislocations do not escape from Hs. No hazy dispersion of releasing dislocations happens. The defect accumulating regions can maintain the state of accommodating dislocations till the end. The problem of the hazy dispersion of dislocations is solved.
[0026] At first it was not clear for the inventors of (3) what kinds of nature the defect accumulating regions H have. Furthermore the property of the defect accumulating regions H is not uniquely determined. Sometimes the defect accumulating region H is a polycrystal. Sometimes the defect accumulating region H is a single crystal having crystal axes inclining at a slight angle to the other regions of the growing crystal. In these cases of polycrystal or inclining axis single crystal, the above-mask defect accumulating regions H are insufficient to work as a defect annihilating/accommodating device. Sometimes no defect accumulating regions happen on masks. In this case, the facets 26 penetrate and grow on the mask 26 . The pits are only shallow cavities. The regions above the masks do not act as a defect annihilating/accommodating device. Sometimes the defect accumulating region H is a single crystal with the c-axis which is inverse to the c-axis of the surrounding crystals Z and Y. Defect accumulating regions H have manifold variations. What types of defect accumulating region appear on masks depends upon the conditions of growth.
[0027] The best of the defect accumulating regions is the c-axis inversion single crystal which has a c-axis [0001] entirely inverse to the c-axis [0001] of the surrounding regions Z and Y. The region is named as an orientation inversion region, a c-axis inversion region, a polarity-inversion region or an inversion region J. All are synonyms. When the orientation inversion region is made as a defect accumulating region H, the orientation is inversely rotated at an interface. Thus continually definite grain boundary K is produced between the inner inversion defect accumulating region H and outer single crystal regions Z and Y. The continual grain boundary K has a strong function of annihilating and accommodating dislocations. A cavity, a polycrystal or a c-axis inclining regions have insufficient defect annihilating/accommodating function.
[0028] The surrounding regions are also divided into two categories. The regions growing below facets on exposed parts are named “low defect density single crystal regions” Z. The regions growing below the C-planes on exposed parts are called “C-plane growth regions” Y. Both Z and Y are single crystals with common orientation and common c-axes and low defect density. However, Z and Y are different in electrical property. The C-plane growth regions Y have high resistivity. The low defect density single crystal regions Z have low resistivity.
[0029] The low defect density single crystal regions Z and the C-plane growth regions Y are single crystals having an upward directing c-axis [0001]. The inversion regions J, which are the best type of the defect accumulating regions H, have inverse single crystals having a downward directing c-axis [0001]. Orientation is inverse. Definite, stable, continual grain boundaries K are produced by the inversion of orientation between the inversion regions J and the surrounding regions Z. The grain boundaries K have effective functions of annihilating and arresting dislocations. Thus it is an advantage for the inversion regions J to establish grain boundaries K between the defect accumulating region H and the surroundings Z. The grain boundary K enables the defect accumulating region H to discern the inner space S from the outer space Z.
[0030] The most effective way in reducing dislocation density is to produce the (polarity, orientation) inversion regions J on masks as defect accumulating regions H.
[0031] The growing speed of defect accumulating regions H is lower than the speed of the surrounding regions Z and Y. The defect accumulating regions H become cavities. The defect accumulating regions H can stably stay at bottoms of pits or valleys. The defect accumulating regions H stay at the bottoms of inverse hexagonal cone pits.
[0032] Dislocations are annihilated with a high efficiency at grain boundaries K enclosing the defect accumulating regions H. The grain boundary prohibits once gathered dislocations from escaping from H. The grain boundary inhibits hazy dispersion from occurring. The grain boundaries enable us to make low defect density GaN crystals which encapsulate dislocations within the defect accumulating regions H.
[0033] The regions of generating the defect accumulating regions H are possible to be fixed at arbitrary positions. The defect accumulating regions H do not accidentally happen to occur but are formed at predetermined positions, whereby it is possible to make good quality GaN crystals with regularly aligning defect accumulating regions H.
[0034] Shapes of the defect accumulating regions H have some different versions. For example, a set of regularly aligning isolated dots is one version. Aforementioned (3) Japanese Patent Laying Open No. 2003-165799 has proposed GaN crystals having such dotted defect accumulating regions.
[0035] FIG. 10 ( 1 ) shows a plan view of an example of a dotmask. Many regularly aligning isolated mask dots M are produced upon an undersubstrate U. When GaN is grown on the dotmasked undersubstrate, low defect density good quality GaN crystals are made upon wide exposed parts. Defect accumulating regions H occur on the regularly aligning isolated dots M. Facet pits whose bottoms correspond to tops of the defect accumulating regions H are yielded. The regions below the facets become low defect density single crystal regions Z. Out of the facets, a continual C-plane growth region Y is grown.
[0036] FIG. 6 ( 2 ) shows a perspective view of a part of the GaN crystal grown on the dotmask-formed undersubstrate U. The flat top surface is a C-plane. The regions below the C-plane is C-plane growth region Y. Many pits composed of facets F are produced just above the mask dots M on the surface. The regions just beneath the facets F are low defect density single crystal regions Z. Bottoms of the facet pits coincide with tops of defect accumulating regions H. The defect accumulating regions H are made upon the mask dots M. Since the dotmask-grown GaN crystal has many deep cavities (pits) on the surface, the surface should be ground by more than the depth of the cavities for making a flat surface.
[0037] FIG. 10 ( 2 ) shows a plan view of a part of a freestanding flat GaN substrate crystal obtained by eliminating the undersubstrate U from the bottom of the as-grown GaN crystal of FIG. 6 ( 2 ) and grinding the rugged surface of the GaN crystal. Comparing FIG. 10 ( 2 ) with FIG. 10 ( 1 ) confirms defect accumulating regions H have been made on mask dots M. Enclosing the defect accumulating region H, low defect density single crystal regions Z and a C-plane growth region Y build a repeating concentric structure (YZH).
[0038] Another type of masks is a stripemask which has many parallel mask strips for making stripe structure type GaN crystals. (4) Japanese Patent Laying Open NO. 2003-183100 proposed a GaN crystal having a stripe structure. An example of a stripemask is shown in FIG. 8 ( 1 ). A plurality of parallel mask stripes M are formed upon an undersubstrate U. The width of a stripe M is s. The pitch of stripes is p.
[0039] FIG. 6 ( 1 ) demonstrates a GaN crystal grown on the stripemask-carrying undersubstrate ( FIG. 8 ( 1 )). Parallel mountain ranges composed of low defect density single crystals Z are produced on exposed parts of the undersubstrate U. Slopes of the mountains are facets F. A mountain range is composed of two conjugate facets F. Sometimes flat tops of C-planes appear between two conjugate facets F. V-grooves between mountains are defect accumulating regions H, which are produced upon the mask stripes M. A freestanding GaN substrate is obtained by removing the undersubstrate U and grinding the superficial mountains. FIG. 8 ( 2 ) is a plan view of a GaN wafer by separating the GaN crystal from the undersubstrate U and grinding/polishing the rugged surface. The GaN wafer has a parallel HZYZHZYZH . . . structure.
[0040] FIG. 5 demonstrates the on-stripemask facet growth method. Parallel mask stripes M are formed on an undersubstrate U ( FIG. 5 ( 1 ) equivalent to FIG. 8 ( 1 )). The mask stripe M extends in the direction vertical to the sheet. GaN is grown in vapor phase on the stripemask-covered undersubstrate U. The undersubstrate U allows GaN nuclei to happen. The mask stripes M prohibit GaN from producing nuclei. No GaN crystal growth happens on stripes M. GaN crystals grow on exposed parts in the direction of the c-axis. FIG. 5 ( 2 ) demonstrates the initial step of the GaN growth. The flat top of the growing GaN crystal is C-plane. The mask has a function of prohibiting GaN from epitaxially growing. The upper space above the mask M is vacant at the initial stage.
[0041] Growing GaN crystals come close to verges of masks and fill the exposed parts. Slants expanding upward from the verges of the masks to the C-plane tops are facets F. A further progress of growth forces GaN crystals to pile also on the masks M. Delay of growth on the mask makes a cavity at the mask M. The region on the mask M is a c-axis inversion defect accumulating region H. On the c-axis inversion defect accumulating region, other kind of facets F′, F′ having a smaller inclination lie. The facets F′ has an inclination common to the upper slope of the small polarity inversion crystals Q appearing in FIG. 7 ( 3 ) and FIG. 7 ( 4 ). The crystals grown on exposed parts below the facets F are low defect density single crystal regions Z. The crystals grown on exposed parts below the flat C-plane are C-plane growth regions Y. The interfaces between the defect accumulating regions H and the low defect density single crystal regions Z are grain boundaries K. The interfaces between the steeper facets F and the milder facets F′ coincide with the tops of the grain boundaries K.
[0042] Since mask stripes M are plural and parallel, defect accumulating regions H form parallel valleys on the stripes M. The intermediate portions between neighboring stripes become low defect density single crystal regions Z or C-plane growth regions Y. The low defect density single crystal regions Z and the C-plane growth regions Y make parallel mountains. On the stripemask case, the facet growth makes a structure with repeating parallel valleys and mountains. When no C-plane growth region happens, sharp mountain ranges (consisting of Z) without flat tops are produced. When C-plane growth regions occur, the mountains (composed of Z and Y) have blunt tops. The above is the stripemask case.
[0043] The formation of Z, Y, and H on the dotmask-carrying undersubstrate is similar to the formation of Z, Y and H on the stripemasked undersubstrate. In the dotmask case, isolated facet pits having a center of a mask dot are yielded. The hexagonal regions following the facets F on an exposed part are low defect density single crystal regions Z. The other region below the C-plane surface on an exposed part is a C-plane region Y, which is a continual region. Z and Y are both low defect density single crystals.
[0044] The regions upon the mask dots M become defect accumulating regions H. There are several different types in defect accumulating regions H. One type is a polycrystal (P). Another type is a c-axis inclining single crystal (A). Another type is a c-axis inverting single crystal (J). “c-axis inversion”, “polarity inversion”, “orientation inversion” or “inversion” are all synonyms for indicating an orientation inversion region J. Sometimes no defect accumulating region happens (O) on the dots (M). Thus the defect accumulating regions H have four alternatives O, A, P and J.
[0045] When inversion regions J are borne on masks (H=J), the defect accumulating region H(=J) has an inverse Ga-surface and an inverse N-surface. The c-axis is inverse in J. The orientation is inverse in J. The polarity is inverse in J. The inversion region H is named “polarity inversion” region by the inventors. In general compound semiconductors are polarized crystal. GaN has wurtzite structure composed of Ga atom layers and N-atom layers alternately piling on each other at different intervals in the c-axis direction. The different interval allots GaN with polarity in the direction of the c-axis. The c-axis inversion regions J (H=J) has a c-axis by 180 degrees inverse to the surrounding GaN crystals.
[0046] The interface between Z and H is a grain boundary K. Tops of the inversion defect accumulating region H(=J) are milder facets F′ with an inclination angle smaller than the facet F above Z on the exposed parts. The grown GaN crystal has many isolated pits aligning in a C-plane surface. Sectional view of a pit of a dotmask-grown GaN seems to be similar to a section of a valley of a stripemask-grown GaN. In the dotmask-grown GaN, a defect accumulating region H on a dot is an isolated closed region. Facets appearing around H are mainly {11-22} and {1-101} planes. The masks M are seeds of the defect accumulating regions H.
[0047] The positions at which masks are formed on an undersubstrate at first determine the positions at which defect accumulating regions H occur in the vapor phase growth. The positions at which Z and Y happen are determined. The (1) Japanese patent Laying Open No. 2001-102307 (random)-relevant problem of undetermined, random positions of defect accumulating regions H is solved by forming masks on undersubstrates and making inversion regions J on masks.
[0048] The defect accumulating region H which is an inversion region J has a definite grain boundary K. The grain boundary K prevents once gathered dislocations from releasing again as hazy dispersion. Reformation of the masks enables the facet growths of (3) Japanese Patent Laying Open No. 2003-165799 and (4) Japanese Patent Laying Open NO. 2003-183100 to control the positions of defect accumulating regions H.
[0049] The facet growth methods succeed in determining the positions of Hs, Zs and Ys. Then a new matter rises to the surface. A defect accumulating region H sometimes makes a definite grain boundary and sometimes cannot make a continual definite grain boundary. Occurrence or non-occurrence of grain boundaries depends upon specific conditions. Even if a defect accumulating region H happens on a mask, the defect accumulating region H does not always become a 180 degree c-axis inversion region J. Sometimes the defect accumulating region H becomes a polycrystal (P). Otherwise the defect accumulating region H becomes a c-axis inclining single crystal (A) whose c-axis is different from the c-axis of the surroundings (Z and Y). Sometimes no defect accumulating region (O) happens. The regions on masks have four kinds of versions O, A, P and J.
[0050] When the defect accumulating regions H built on masks are polycrystals (P), some crystals have orientation similar to the surroundings Z. No definite orientation discrepancy happens between the partial crystals and the surroundings Z. No definite grain boundary occurs therebetween. When the defect accumulating region formed on masks is a single crystal with a c-axis inclining to the c-axis of the surroundings Z, some portion has orientation similar to the surrounding crystals Z. A definite, continual grain boundary K is not produced between H and Z. A vague grain boundary K has a weak power of arresting dislocations and is easy to allow dislocations to disperse. When the defect accumulating region H is a polarity inversion region J, the orientation of all the parts of H is different from the surroundings Z. A continual definite grain boundary K is surely produced between J and Z. The continual grain boundary K has a strong function of arresting and accommodating dislocations without releasing.
[0051] Without definite grain boundaries K, the defect accumulating regions H has a weak power inadequate to arrest and annihilate dislocations. Grain boundaries K are made by the on-mask orientation inversion regions J and the surrounding crystals with normal orientation. Thus the formation of inversion regions J on masks is ardently required to arrest, annihilate and accommodate dislocations firmly in the defect accumulating regions H. The inversion region J is the best alternative of the defect accumulating region H. An object of the present invention is to provide a reliable method of making inversion regions J on masks as defect accumulating regions H.
[0052] It is the best that inversion regions J are generated on masks as defect accumulating regions H. If GaN crystals with no or few inversion regions J are produced by the facet growth, once arrested dislocations in defect accumulating regions H will be released from the defect accumulating regions H as hazy dispersion. The surrounding regions will be not low defect density but high defect density GaN. When blue/violet GaN type LDs are produced on a high defect density GaN substrate, the yield of accepted products will be low. The GaN substrate will be useless. It is strongly desired to make inversion regions J on masks as defect accumulating regions H. A series of steps of causing inversion regions J on masks are in detail observed for clarifying the conditions of producing inversion regions J. The steps are explained by referring to FIG. 7 ( 1 )-( 5 ).
[0053] Step (1): Step (1) forms masks M at positions for inducing defect accumulating regions H on a surface of an undersubstrate U. The material of the masks has a function of inhibiting GaN from epitaxially growing. The masks become seeds of the defect accumulating regions H. Thus a seed is a synonym of a mask. FIG. 7 ( 1 ) denotes a part of an undersubstrate U covered with masks M. FIG. 7 ( 1 ) shows only one mask stripe in brief, but many mask stripes M actually cover the undersubstrate U.
[0054] Step (2): Step (2) grows GaN on the masked undersubstrate in vapor phase. Exposed parts allow GaN nuclei to happen. Masks prevent GaN nuclei from occurring. GaN grows only on exposed parts. The GaN crystals have C-plane tops. Masks are not covered with GaN. Progress of growth is stopped at the verges of masks. GaN crystals do not overstep masks at an initial stage. Inclinations starting from the verges of masks and attaining to the top C-plane are formed as demonstrated in FIG. 7 ( 2 ). The inclinations are some kinds of facets except C-plane. Facets confront each other across the mask. In many cases, the facets are {11-22} planes. When a stripemask M is formed on an undersubstrate, V-grooves are formed on masks extending in the direction vertical to paper. When a dotmask consisting of isolated dots is formed, isolated pits composed of facets are formed on masks. FIGS. 7 ( 1 )-( 5 ) show the case of a stripemask. The steps are similar to the case of a dotmask.
[0055] Step (3): Small beaks Q and Q having c-axes of 180 degree inverting orientation appear midway on the inclinations of GaN facets whose growth is stopped at the lower ends by the edge of the mask, as shown in FIG. 7 ( 3 ). The beaks Q have upper milder and lower steeper inclinations different from the facets F. It turns out that the beaks Q are c-axis inverting crystals (polarity inversion). If the beaks Q dilate, desired inversion regions J are generated on the dilated beaks Q.
[0056] Step (4): The progress of the crystal growth increases the number and volume of the inversion beaks Q grown on the facets F. The beaks Q join in series along the extensions of facets F. Trains of beaks are produced on the facets in the longitudinal direction. Each facet has a long beak train. A pair of inversion beaks Q and Q on confronting facets spread over a mask and cover the mask.
[0057] Step (5); A beak Q has a milder facet F′ on an upper side and a steeper facet on a lower side. The upper facets F′ are low inclination facets {11-2-6} or {11-2-5}.
[0058] Step (6): The polarity inversion beaks Q dilate in the horizontal and vertical directions. Tips of the beaks Q and Q collide with and couple with each other above the mask. As shown in FIG. 7 ( 4 ), a bridge composed of the confronting beaks is formed between the paired facets. The bridges have c-axis inverting (orientation inversion) crystals. GaN grows on the bridges, having the same inversion orientation. Gaps between the bridge and the mask are filled with inversion crystals. The on-mask crystals are not made by depositing GaN directly on the mask but are made by piling GaN on the inversion bridges above the masks. The inversion regions J grow upward. The gap below the bridge is also filled with polarity inversion crystals.
[0059] Step (7): Collision parts J and J grow thicker with lattice misfit boundaries K′ therebetween. The lattice misfit boundaries K′ between J and J are different from the grain boundaries K between the polarity inversion region J and the low defect density single crystal regions Z. The polarity inversion regions J become defect accumulating regions H.
[0060] Step (8): As GaN crystals grow thick, dislocations in the GaN crystals are gathered from the surrounding GaN regions into the inversion regions J on the masks M through the growth of the slanting facets. A part of the dislocations gathered is annihilated at the grain boundaries K between the polarity inversion regions J and the low defect density single crystal regions Z or the cores S of the inversion regions J. Upward extending inversion regions J become defect accumulating regions H by gathering dislocations D. The rest of the dislocations are arrested and accommodated in the grain boundaries K and the cores S of the defect accumulating regions H. The surrounding regions under facets become low defect density single crystal regions Z.
[0061] Such a process forms orientation inversion regions J on masks M as defect accumulating regions H. On-mask formation of the orientation inversion regions J requires stable occurrence of the polarity inversion beaks Q midway on all the facets, for example {11-22} planes. Without stable happening of the beaks Q, defect accumulating regions H on masks do not become polarity inversion regions J. Without polarity inversion regions J, dislocations are not fully pulled into the defect accumulating regions H on masks. Non-existence of the polarity inversion regions J allows dislocations once gathered to escape from the bundles 11 below the bottoms of facets as show in FIG. 3 ( 2 ). Without the polarity inversion regions J, the surroundings do not become low defect density single crystals.
[0062] Blunt vapor phase growth on masked undersubstrate cannot necessarily make inversion regions J on masks. It is not easy to stably produce polarity inversion regions Q upon slanting facets F rising from the verges of masks. Nobody has reported the conditions of making polarity inversion crystals on determined positions of growing GaN crystals. Furthermore nobody has clarified the conditions of yielding polarity inversion crystals on growing any kinds of crystals throughout the history of crystal growth.
[0063] The present invention aims at reducing dislocations by facet growth. Thus the present invention can be called a “facet growth method”. This invention is clearly different from the ELO (Epitaxial Lateral Overgrowth) method which decreases dislocations by making use of masks. The facet growth on which the present invention relies distinctly differs from the ELO. Both methods may be confused because of a common point of making use of masks for decreasing dislocations. Differences (a)-(c) are now clarified for avoiding confusion of the facet growth with the ELO.
[0064] Difference (a): Both methods are different with regard to existence or non-existence of the polarity inversion regions on masked parts. The ELO allows GaN crystals generated on exposed parts to overstep with maintaining the original orientation on masked parts. The orientation on the coated parts is the same as the orientation on the exposed parts in the ELO. In the ELO, a GaN crystal having, for example, a {11-22} facet on an exposed part will directly overstep onto a mask with keeping the same {11-22} facet. No orientation (polarity) inversion occurs at the verges of mask in the ELO. In the facet growth, GaN crystals produced on expose parts do not directly overstep on masks. Polarity (orientation) inversion regions Q happen at midway points on facets separating from masks at an early step. The polarity inversion regions J happen discontinuously from the mask. The facet growth has polarity inversion regions J on masks. The ELO has no polarity inversion regions J.
[0065] Difference (b): The direction of crystal growth for reducing dislocations is horizontal directions in the ELO. The ELO reduces dislocations by turning the growth direction from the initial vertical upward direction to horizontal directions at edges of masks. The direction of crystal growth in the facet growth is a vertical direction. The vertical growth has a function of gathering dislocations into the defect accumulating regions H and decreasing dislocation density in the surrounding regions. The facet growth and the ELO differ in the directions of crystal growth.
[0066] Difference (c): The ELO makes low density good quality GaN crystals on masks. High dislocation density poor quality GaN crystals are made on exposed parts in the ELO. On-mask crystals are good and off-mask crystals are poor in the ELO. On the contrary, the facet growth makes low dislocation density good GaN crystals on exposed parts and yields high dislocation density poor GaN crystals on masks. On-mask crystals are bad and off-mask crystals are good in the facet growth. The ELO and the facet growth are entirely contradictory with regard to whether low defect density GaN crystals and high defect density GaN crystals are made on exposed parts or coated parts.
OBJECTS AND SUMMARY OF THE PRESENT INVENTION
[0067] This invention proposes a facet growth method of growing GaN crystals on an undersubstrate by depositing epitaxial growth-inhibiting masks partially on the undersubstrate, preparing a mixture of exposed parts and masked parts on the undersubstrate, growing GaN crystals on the partially coated undersubstrate in vapor phase, making polarity inversion regions J on the masks and growing a thick GaN crystal on the polarity inversion region-made undersubstrate in the facet growth condition till the end. The conventional GaN vapor phase growth contains two steps of buffer layer formation and epitaxial growth. This invention adds a step of inversion region formation. This invention includes three steps of buffer layer formation, inversion region formation and epitaxial growth.
[0068] The undersubstrate is a sapphire (Al 2 O 3 ) (0001) single crystal wafer, a silicon (Si) (111) single crystal wafer, a silicon carbide (SiC) (0001) single crystal wafer, a GaN single crystal wafer, or GaAs (111) single crystal wafer. A GaN/sapphire wafer which is made by coating a sapphire wafer with a thin GaN film is called a “template”. The GaN/sapphire template can be also an undersubstrate.
[0069] A mask pattern is deposited on the undersubstrate. The materials of the mask are silicon dioxide (SiO 2 ), platinum (Pt), tungsten (W), silicon oxide nitride (SiON), silicon nitride (SiN), and so on. There is no problem using other materials capable of having thermochemical stability under the conditions of vapor phase growth and having the function of preventing GaN from epitaxially growing thereupon. The thickness of the mask is 30 nm to 300 nm. A mask pattern should be composed of regularly distributing masks. For example, one available mask pattern is a dot-type mask pattern (M 2 ) which aligns many isolated mask dots in regular repetitions at a definite pitch. The dot-type mask pattern is now called a “dotmask” (M 2 ) for short. Another available mask pattern is a stripe-type mask pattern (M 1 ) which aligns parallel mask stripes at a definite pitch. The stripe-type mask pattern is called a “stripemask” (M 1 ).
[0070] Parts coated with masks are named “covered parts” or “masked parts”. Other parts not coated with masks are named “exposed parts”, since the undersubstrate is exposed at the parts. In any of the facet growth masks, exposed parts are wider than the covered parts. The exposed parts can be true exposed parts without any mask. But the exposed parts otherwise can be coated with a fine ELO mask or a fine HELO mask having a several micrometer width and a several micrometer pitch. The ELO mask is far smaller than the facet growth masks in width and pitch. The ELO mask has a wider continual covered part than exposed parts. The narrow exposed parts in the ELO mask are called “windows”. On the ELO mask-formed exposed parts, GaN crystals happen on windows and overstep on masks in horizontal directions continually. The polarity inversion does not occur. The same orientation is always kept on the exposed parts. Dislocations are slightly reduced by the function of the ELO or HELO mask at an initial stage. The orientation and polarity are maintained on the ELO mask-formed exposed parts. Thus in spite of the existence of the ELO mask, the parts are still called “exposed parts”.
[0071] A GaN buffer layer with a thickness of 30 nm to 200 nm is formed on the mask-formed undersubstrate by growing GaN in vapor phase at a low temperature. The buffer layer formation temperature is denoted by Tb. The buffer layer formation temperature is a low temperature of Tb=400° C. to 600° C. The buffer layer has a function of alleviating the stress caused between the undersubstrate and GaN layers. The buffer formation growth is the zero-th growth.
[0072] The gist of the present invention is the first growth for making inversion regions J following the zero-th growth. The purpose of the first growth is to produce inversion regions J on masks. In the first growth, GaN crystals happen and grow on exposed parts, and masks prevent GaN from growing thereon. GaN crystals on exposed parts make inclining facets F at portions in contact with brims of masks. In the optimum case, small beaks Q happen midway on facets F which start from the verges of masks and arrive at C-plane surfaces of growing GaN crystals on exposed parts. The beaks have orientation inverting by 180 degrees to the surrounding crystals. Progress of GaN crystal growth dilates and prolong the beaks Q on the facets, maintaining the inversion of orientation. Tips of a pair of beaks Q and Q come into contact with each other. The beaks Q and Q are unified into one above masks. GaN is epitaxially piled on also the unified beaks Q as seeds. GaN crystals are grown also above the masked parts with delay. The GaN crystals growing on the beaks Q have orientation and polarity by 180 degrees inverting to the surrounding GaN crystals. Then the regions are named “orientation inversion regions” J. In the orientation inversion regions J, polarity, c-axis and other axes are inversion. “Polarity inversion regions”, “c-axis 180 degree inversion regions”, “inversion regions” and “orientation inversion regions” are synonyms. The inversion region J upward grows on the mask with maintaining a definite horizontal section of an area slightly smaller than the mask. The polarity inversion regions J as defect accumulating regions H attract, gather and accommodate dislocations.
[0073] Since the on-mask regions assemble dislocations, the regions on the masks are called “defect accumulating regions” H. The defect accumulating regions H have four different types; A, P, J and O. One type is a c-axis inclining single crystal (A). Another type is a polycrystal (P). Another type is a c-axis inversion region J. Sometimes any defect accumulating regions are not produced (O) on masks.
[0074] Among the four types of A, P, J and O, the present invention aims at making the inversion regions J on masks as defect accumulating regions H. The on-mask defect accumulating regions H have a function of attracting dislocations out of the neighboring GaN crystals grown below facets and arresting the dislocations in the defect accumulating regions H. The neighboring GaN crystals from which dislocations are swept become low defect density. The dislocation attracting function is the strongest in the inversion region J. Three other types of H have a weaker function of gathering/arresting dislocations than the inversion region J. The inversion region J is the best for defect accumulating regions H.
[0075] Searching the conditions of making inversion regions on masks with certainty, the present invention succeeds in producing inversion regions J on masks by facet growth without fail.
[0076] Cathode luminescence is able to examine the occurrence or non-occurrence of orientation inversion regions on masks. A fluorescence microscope can inspect whether orientation inversion regions J happen on masks. GaN crystals are transparent for visible light. Human eye sight cannot examine the structure on the masks.
[0077] For forming the c-axis inversion regions J as defect accumulating regions H, the inventors have found the fact that the conditions of forming defect accumulating regions on masks at an initial stage are important. If the initial conditions of forming the on-mask defect accumulating regions H are not well adjusted, the on-mask defect accumulating regions H do not become polarity inversion regions J but become polycrystals (P) or c-axis inclining single crystals (A). Otherwise defect accumulating regions do not occur on masks and the on-mask regions (O) only become shallow cavities. The polycrystal (P) or c-axis inclining single crystal (A) has an insufficient power for attracting dislocations from the surrounding regions, annihilating dislocations and accommodating dislocations without release. The simple cavities (O) without defect accumulating regions H on masks have no power of attracting dislocations. The best of the defect accumulating regions H is the inversion region J. It is ardently desired to convert the on-mask regions to the polarity inversion regions J.
[0078] Among the aforementioned processes, steps (3), (4), (5) and (6) correspond to the initial stage of forming polarity inversion beaks Q. Occurrence of the polarity inversion beaks Q is very important. The present invention clarifies the conditions of making polarity inversion beaks Q and the following polarity inversion regions J. It should be clarified what range of temperatures, what range of growing speeds, what kind of undersubstrates and what kind of mask materials are suitable for making polarity inversion regions on masks. The aim of the present invention is, as it were, to answer the questions.
[0079] The growth which produces the inversion beaks Q and the polarity inversion regions J is called a “first growth”. The growth temperature which makes the beaks Q and the inversion regions J is called a “first growth temperature” Tj(° C.). When tiny beaks Q and inversion regions J once happen, a thick GaN crystal is grown on conventional facet growth conditions. The time required for making the inversion regions J, which depends upon the growing speed, is a short time of about 0.25 hour to 2 hours.
[0080] Plenty of experiments teach the inventors that first growth temperatures ranging Tj=900° C. to 990° C. enable inversion regions J to happen on all or almost of the masks and allow the neighboring regions Z to become low dislocation density. The temperature range Tj=900-990° C. had been deemed to be too low and unsuitable for vapor phase epitaxy of CaN crystal. In general, it has been believed that higher temperature growth is favorable for making high quality GaN crystals. GaN epitaxial growth in vapor phase had been done at a high temperature more than 1000° C. The inventors have found that low temperatures of 900° C. to 990° C. are pertinent for making inversion regions J on masks without fail at an early stage. The pertinent range of the first temperature of 900° C. to 990° C. is less than the conventional epitaxial growth temperature (higher than 1000° C.).
[0081] The inventors have discovered that a more restricted range of the first growth temperature Tj=920° C.-960° C. enbles a wide scope of different growing speeds Vj to produce inversion regions J on allover masks M. The range of Tj=920° C.-960° C. as first growing temperatures Tj is more favorable for making GaN substrate crystals in industrial scale, since the temperature range allows the facet growth to yield inversion regions J and low defect density single crystal regions Z with high stability.
[0082] The inventors have carried out many systematical experiments of growing GaN crystals within and beyond the above temperature range for searching preferable conditions of making inversion beaks on facets. FIG. 11 is a graph showing results of experiments of the first growth as a function of temperature T (K) and growing speed Vj(μm/h). The abscissa is 1000/T. The ordinate is growing speed Vj(μm/h). Black rounds signify very good sets of a growth temperature T and a growing speed Vj which succeed in making continual inversion regions J. 13 black rounds appear in the graph of FIG. 11 . The leftest black round has 1000/T=0.792. Then T=1263K, Tj=990° C. The rightest black round denotes 1000/T=0.853. Thus T=1172K. Tj=899° C. All the 13 black rounds are included in a range of temperatures between 900° C. and 990° C.
[0083] Blank rounds signify allowable sets of T and Vj which make intermittent inversion regions J. Some blank rounds are included within the temperature range Tj=900° C.-990° C. Some blank rounds (rightest) exist at lower temperatures under 900° C. Other blank rounds (leftest) exist at higher temperatures over 990° C. All the blank rounds are sandwiched by two straight lines. Then the scope of the allowable T and Vj can be expressed by inequalities.
[0084] Blank triangle denote rejected sets of T and Vj which cannot make inversion regions J. All the blank triangles are out of the two straight lines. The condition of the first growth for yielding inversion regions J depends upon a growing speed Vj (μm/h) as a function of the temperature Tj. The range of preferable growing speeds depends upon the first growth temperature Tj. The preferable first growth temperature Tj (° C.) and the favorable growing speed Vj (μm/h) are mutually related with each other. The inventors have found that the condition of making inversion regions J on masks is a scope of Vj and Tj which is expressed by the following inequalities.
−439×{1000 /{Tj+ 273.15)}+387 <Vj<− 736×{1000/( Tj+ 273.15)}+737.
[0085] The condition defined by the above inequalities is favorable for yielding inversion beaks Q and inversion regions J. The above inequalities include temperature in Celsius (° C.). Tj(° C.)+273.15 is an absolute temperature (Kelvin) T(K). T(K)=Tj+273.15. An equivalent expression in term of absolute temperature T(K) is given by,
−4.39×10 5 /T+ 3.87×10 2 <Vj<− 7.36×10 5 /T+ 7.37×10 2 .
[0086] The inequalities are obtained by the two straight lines which are drawn for discriminating the allowable T and Vj sets (blank rounds) from the rejected T and Vj sets (blank triangles) in FIG. 11 . The upper line is denoted by Vj<−7.36×10 5 /T+7.37×10 2 . The lower line is denoted by Vj=−4.39×10 5 /T+3.87×10 2 . An equivalent expression of the favorable sets of T(K) and Vj(μm/h) is given by
a 1 /T+b 1 <Vj<a 2 /T+b 2 ,
where a 1 =−4.39×10 5 (Kμm/h), b 1 =3.87×10 2 (μm/h), a 2 =−7.36×10 5 (Kμm/h) and b 2 =7.37×10 2 (μm/h). The inequalities include favorable sets (black rounds) and allowable sets (blank rounds) of T and Vj in FIG. 11 .
[0087] The inequalities signify the growing condition corresponding to the scope of growing speeds Vj and temperatures T sandwiched by two solid lines drawn in FIG. 11 . Even if the first growing temperature Tj exceeds the scope between 900° C. and 990° C., the growing speed Vj within the range denoted by the inequalities can make inversion regions J on masks M. The inventors have discovered for the first time the fact that the growing speed and the temperature are mutually related with each other and cooperated in facilitating the occurrence of inversion regions J on masks M.
[0088] It is strongly desired that the first growth should be carried out at a temperature and a growing speed satisfying the above inequalities for making polarity inversion regions J on overall masks. Thereby complete formation of the on-mask inversion regions J should ensure the surrounding crystals to be low dislocation density. However even when inversion regions J are not overall formed but are intermittently formed on most of the masks M, the following facet growth can produce useful GaN crystals. In the case, since most of the masks have inversion regions J, the inversion regions J attract, arrest and annihilate dislocations and the surrounding crystals become low defect density.
[0089] Pertinent ratios P NH3 /P HCl of ammonia partial pressure P NH3 to hydrochloride partial pressure P HCl are P NH3 /P HCl =3 to 50 in the first growth. The ammonia partial pressure P NH3 should be equal to or higher than 5 kPa but equal to or lower than 30 kPa in the first growth.
0.05 atm (5 kPa)≦ P NH3 ≦0.3 atm (30 kPa)
[0090] The time of the first growth is 0.25 hour to 2 hours. At the end of the first growth, orientation inversion regions J have been made on masks as defect accumulating regions H. Low defect density single crystal regions Z are produced upon exposed parts. Sometimes C-plane growth regions Y are made at middles of the exposed parts. Sometimes no C-plane growth regions Y happen.
[0091] Following the first growth, epitaxial growth for making a thick GaN crystal is done. The growth for producing a thick GaN crystal is called a “second growth”. The time of the second growth, which depends upon the thickness of an object GaN crystal, is several tens of hours, several hundreds of hours, or several thousands of hours. The temperature of the second epitaxial growth is named a “second growth temperature” Te. The epitaxial growth temperature Te should be higher than 990° C. (Te>990° C.). An appropriate second temperature range is Te=1000° C. to 1200° C.
[0092] High quality GaN substrates of low defect density are ardently desired. The present invention clarifies the conditions of producing inversion regions J on masks as defect accumulating regions H at an initial stage in the facet growth method composed of the steps of implanting masks M on an undersubstrate U, growing GaN in vapor phase, inducing facets on a growing GaN crystal, preparing defect accumulating regions H on the masks at pits or grooves, maintaining facet pits or facet grooves, gathering dislocations into the facet pits or the grooves and decreasing dislocation density in the surrounding regions. The present invention demonstrates requisite conditions of preparing inversion regions J on masks M. The present invention gives high quality GaN substrate crystals by adjusting the first growth temperature and the first growing speed, enabling masks to make definite inversion regions J and allowing the inversion regions J to decrease dislocations in the surrounding single crystal regions Z and Y.
BRIEF DESCRIPTION OF THE DRAWINGS
[0093] FIG. 1 ( a ) is a perspective view of a facet pit appearing on a growing surface at a starting stage of growth for demonstrating the facet growth method proposed by (2) Japanese Patent Laying Open No. 2001-102307 which makes hexagonal facet pits on a growing surface, grows GaN without burying the facet pits, concentrates dislocations at boundaries of the facets and gathers dislocations at bottoms of the facet pits.
[0094] FIG. 1 ( b ) is a perspective view of a facet pit appearing on a growing surface at a later stage of growth for demonstrating the facet growth method proposed by (2) Japanese Patent Laying Open No. 2001-102307 which makes hexagonal facet pits on a growing surface, grows GaN without burying facet pits, concentrates dislocations at boundaries of the facets and gathers dislocations at bottoms of the facet pits.
[0095] FIG. 2 is a plan view of a facet pit appearing on a growing surface for demonstrating the facet growth method proposed by (2) Japanese Patent Laying Open No. 2001-102307 which makes hexagonal facet pits on a growing surface, grows GaN without burying facet pits, concentrates dislocations at boundaries of the facets and gathers dislocations at bottoms of the facet pits.
[0096] FIG. 3 ( 1 ) is a sectional view of a facet pit appearing on a growing surface for demonstrating the facet growth method proposed by (2) Japanese Patent Laying Open No. 2001-102307 which makes hexagonal facet pits on a growing surface, grows GaN without burying facet pits, concentrates dislocations at boundaries of the facets, gathers dislocations at bottoms of the facet pits and makes a dislocation bundle.
[0097] FIG. 3 ( 2 ) shows a sectional view of a facet pit with a hazy dispersion of dislocations escaping from the pit.
[0098] FIG. 4 ( 1 ) is a sectional view of a pit or V-groove at an early stage for demonstrating the mask-facet growth method proposed by (3) Japanese Patent Laying Open No. 2003-165799 and (4) Japanese Patent Laying Open No. 2003-183100 which make dislocation-attractive defect accumulating regions (H) on masked parts, make low defect density single crystal regions (Z) under facets, produce C-plane growth regions (Y) under C-plane surface and maintain dislocations in the defect accumulating regions (H).
[0099] FIG. 4 ( 2 ) shows a sectional view of the pit or V-grooves at a later stage for showing dislocations being arrested in the defect accumulating regions (H) without being dispersed till the end of the growth.
[0100] FIG. 5 ( 1 ) is a section of an undersubstrate U and a mask M formed on the undersubstrate U at a start of the facet growth method.
[0101] FIG. 5 ( 2 ) is a section of the undersubstrate, the mask and GaN crystals at a later stage for showing the masked parts prohibited from growth, slanting facets starting from ends of the mask and rising to the C-plane surface.
[0102] FIG. 5 ( 3 ) is a section of the undersubstrate, the mask and GaN crystals at a further later stage for showing the occurrence of a defect accumulating region (H) on the masked parts and appearance of two step facets in the pit or the valley.
[0103] FIG. 6 ( 1 ) is a perspective view of a prism-roofed GaN crystal produced by a facet growth method that forms mask stripes on an undersubstrate, grows GaN in vapor phase, produces facet valleys and makes defect accumulating regions on the stripe-covered parts.
[0104] FIG. 6 ( 2 ) is a perspective view of a pit-roofed GaN crystal produced by a facet growth method that forms mask dots on an undersubstrate, grows GaN in vapor phase, produces facet pits and makes defect accumulating regions on the dot-covered parts.
[0105] FIG. 7 ( 1 ) is a section of an undersubstrate and a mask.
[0106] FIG. 7 ( 2 ) is a section of the undersubstrate, the mask, GaN crystals grown on exposed parts, and facets starting from ends of the mask.
[0107] FIG. 7 ( 3 ) is a sectional view for showing beaks appearing on slants of the facets.
[0108] FIG. 7 ( 4 ) is a sectional view for showing the beaks meeting together above the mask and being unified with each other.
[0109] FIG. 7 ( 5 ) is a sectional view for showing GaN crystals growing on the unified beaks with the same orientation as the beaks.
[0110] FIG. 8 ( 1 ) is a plan view of an undersubstrate and linear parallel mask stripes formed at a pitch p on the undersubstrate.
[0111] FIG. 8 ( 2 ) is a CL (cathode luminescence) image of a facet-grown, sliced and polished GaN crystal having parallel low dislocation single crystal regions (Z), C-plane growth regions (Y) and defect accumulating regions (H).
[0112] FIG. 9 ( 1 ) is a section of an undersubstrate.
[0113] FIG. 9 ( 2 ) is a section of the undersubstrate and mask stripes in the strip-mask facet growth.
[0114] FIG. 9 ( 3 ) is a section of the undersubstrate, the mask stripes, and a thick grown GaN crystal on the masked undersubstrate with defect accumulating regions (H) on the mask stripes, low defect single crystal regions (Z) below facets on exposed parts and C-growth regions below C-plane surfaces on the expose parts.
[0115] FIG. 9 ( 4 ) is a CL image of a flat HZYZHZYZH structured GaN crystal produced by eliminating the undersubstrate from the GaN crystal, grinding the separated GaN crystal and polishing the GaN crystal.
[0116] FIG. 9 ( 5 ) is a CL image of a flat HZHZH structured GaN crystal without C-plane growth regions.
[0117] FIG. 10 ( 1 ) is a plan view of an undersubstrate and isolated mask dots formed at a pitch p with six-fold symmetry on the undersubstrate in the dot-mask facet growth.
[0118] FIG. 10 ( 2 ) is a CL image of a flat HZY hexagonal symmetric GaN crystal produced by eliminating the undersubstrate from the GaN crystal, grinding the separated GaN crystal and polishing the GaN crystal.
[0119] FIG. 11 is a graph showing the occurrence of inversion regions J which depend upon the temperature and the growing speed. The abscissa is 1000/T(K −1 ), where T is an absolute temperature (273+° C.) of the first growth. The ordinate is growing speeds (μm/h). In the graph, black rounds denote that inversion regions J occur upon all the masks M at the temperature and the growing speed. Blank rounds mean that inversion regions happen on most masks at the temperature and the speed. Blank triangles denote that that inversion regions J occur on few masks. Results of Embodiments 1-5 are shown in the graph. Black rounds and blank rounds mean allowable conditions of temperatures and growing speeds for making inversion regions J on masks. Blank triangles mean rejected conditions of temperatures and growing speeds for making inversion regions J on masks. Upper and lower solid lines are drawn between rejected triangles and allowable rounds. Temperatures and growing speeds in the scope sandwiched between the upper line and the lower line promote the occurrence of inversion regions J on masks. The upper line is denoted by V=−7.36×10 5 /T+7.37×10 2 , where V is a growing speed (μm/h) and T is an absolute temperature (K) of the first growth temperature. The lower line is denoted by V=−4.39×10 5 /T+3.87×10 2 . Temperatures and growing speeds out of the scope sandwiched between the upper line and lower line prevent inversion regions J from occurring on masks.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0120] A hydride vapor phase epitaxy (HVPE) method, metallorganic chemical vapor deposition (MOCVD) method, metallorganic chloride (MOC) method and sublimation method are known as a growing method of gallium nitride crystals in vapor phase. The HVPE has an advantage of high speed growth. Recent development enables even the MOCVD method to grow gallium nitride at a high speed more than 50 μm/h. The MOCVD or the MOC may grow gallium nitride in a similar manner explained hereafter. Among the known growth methods, the HVPE is superior in the growing speed, material yield and cost at present. Thus this invention searches appropriate conditions of making orientation inversion regions J only in the HVPE method.
[0121] A flux method makes GaN crystals in liquid phase. More than 40 μm/h growing speed in a flux method has recently been reported. But the growing speed in the flux method is far slower than the reported data. Further, a liquid phase method grows GaN crystals from a material liquid at thermal equilibrium. The principle and condition of the growth of the liquid phase method are far different from the vapor phase methods. Thus liquid phase growth methods are out of the reach of the present invention.
[0122] GaN crystals grown by the HVPE method are described hereafter. The present invention uses, for example, a horizontally long hot-wall HVPE reaction furnace. The horizontal-type furnace has a plurality of horizontally-divided heaters. The heaters can form arbitrary temperature distribution in the horizontal direction in the HVPE furnace. The furnace has a Ga-metal boat with metal gallium at an upstream part and a susceptor for supporting specimens at a downstream part. In a usual case, the crystal growth is done at the atmospheric pressure (1 atm=100 kPa=760 Torr) in the HVPE furnace. The Ga-boat is heated up to 800° C. Ga metal is molten into a Ga liquid. The Ga-metal boat contains a Ga-melt at 800° C. Gas inlet pipes are furnished at an upstream part. A gas inlet pipe introduces H 2 +HCl (hydrogen+hydrochloride) gas in the furnace to the hot Ga-melt. Reaction of HCl with Ga-melt synthesizes gallium chloride (GaCl). GaCl is gaseous. Gaseous GaCl drifts downward toward the susceptor and specimens. H 2 +NH 3 (hydrogen+ammonia) gas is introduced via another gas inlet pipe of the furnace to the vicinity of the susceptor/specimens. Reaction of GaCl with NH 3 makes GaN. Synthesized GaN is piled upon the specimens on the susceptor. GaN is grown on the specimens.
[0123] The present invention forms mask patterns on an undersubstrate. The mask patterns should be made of a material which prevents GaN from epitaxially grow. The mask can be made of SiO 2 (silicon dioxide), SiON (silicon oxide nitride), SiN (silicon nitride), Pt (platinum), W (tungsten) and so on.
[0124] Masks become seeds of defect accumulating regions H. Orientation of growing GaN crystals is determined by the orientation of the undersubstrate. Mask extending directions determine the orientation of the facets generated along the masks. The extension direction of masks should be determined to have a definite relation with the orientation of the undersubstrate.
Embodiment 1
Dependence of Inversion Regions J Upon First Temperature Tj
[0125] Embodiment 1 studies how the occurrence of inversion regions J depends upon the first temperature Tj, which is the temperature at the step of making inversion regions J on masks.
[0000] [1. Undersubstrates (U)]
[0126] 2 inch diameter sapphire single crystal wafers (U 1 ), 2-inch diameter GaAs single crystal wafers (U 2 ) and 2-inch GaN/sapphire wafers (U 3 ) which are 1.5 μm thick GaN layer coated sapphire wafers are prepared. The sapphire wafers (U 1 ) are C-plane ((0001) plane) surface wafers. The GaAs wafers (U 2 ) are GaAs(111)A-plane (Ga-plane) wafers. The GaN/sapphire wafers have C-plane sapphire wafers and 1.5 μm GaN thin layers deposited thereon. GaN/sapphire wafers are sometimes called “templates”.
[0000] [2. Mask Patterns (M)]
[0127] Masks should have a property of inhibiting GaN from epitaxial growing. 0.1 μm thick SiO 2 layers are deposited on three kinds of undersubstrates U 1 , U 2 and U 3 . Photolithography and etching pattern the SiO 2 layers into definite masks on the undersubstrates. The masks have two patterns. One is a stripemask (M 1 ) having plenty of parallel mask stripes aligning at a definite pitch. The other is a dotmask (M 2 ) having isolated mask dots aligning two dimensionally regularly at a definite pitch.
[0000] (M 1 : Stripemask Pattern: FIG. 8 ( 1 ))
[0128] FIG. 8 ( 1 ) exhibits a stripemask pattern (M 1 ) consisting of parallel stripes formed on an undersubstrate (U). The extension direction of mask stripes is parallel with a GaN <1-100> direction. The mask is formed before the GaN epitaxial growth. There is no GaN layer on an undersubstrate when the mask is formed. There is a definite relation between the undersubstrate orientation and the GaN orientation. The GaN orientation can be known from the undersubstrate orientation. When a GaN layer is grown on a sapphire (0001) wafer, orientation of GaN is twisted by 90 degrees around the c-axis. When a GaN layer is grown on a GaAs(111) wafer, attention should be paid to the relation between the GaAs and GaN orientations, since hexagonal system GaN is grown on three-fold symmetric GaAs(111) surface. When a GaN layer is grown on a GaN (0001) wafer, the orientation of GaN layer is identical to the orientation of the GaN wafer. Mask patterns parallel to GaN<1-100> direction can be formed on an undersubstrate by taking account of the relation to GaN/undersubstrate orientations.
[0129] Stripemasks having stripes parallel to GaN<1-100> can be prepared by the following guidelines. In the case of a GaN/sapphire template undersubstrate (U 3 ), mask stripes should be determined to be parallel to a GaN<1-100> direction. In the case of a GaAs(111)A-plane undersubstrate (U 2 ), mask stripes should be determined to be parallel to a GaAs<11-2> direction. In the case of a sapphire (0001) undersubstrate (U 1 ), mask stripes should be determined to be parallel to a sapphire <11-20> direction.
[0130] The stripemask pattern has covering stripes having a width s=30 μm and repeating at a pitch p=300 μm. There are parallel undersubstrate-exposed parts with a width e=270 μm. Masked parts are called covered parts. The sum of an exposed part width e and a stripe width s is equal to a pitch p. Namely p=e+s. A pitch is a distance between the center of a covered part and the center of a neighboring covered part. In the example, the ratio of exposed parts to covered parts is 9:1. Exposed parts are far wider than covered parts.
[0000] (M 2 : Dotmask Pattern: FIG. 10 ( 1 ))
[0131] FIG. 10 ( 1 ) shows a dotmask pattern having a plurality of parallel trains of isolated round dots aligning with a half pitch discrepancy. Diameter of a dot is denoted by t. Pitch of repetitions is denoted by p. Distance between neighboring dots is denoted by f. f+t=p. The pattern consists of dots laid on the corners of equivalent regular triangles repeating in three directions without gap. The pattern has six fold rotation symmetry as shown in FIG. 10 ( 1 ). The directions of the dot trains are predetermined to be parallel to GaN<1-100> directions. As mentioned before, although mask formation precedes GaN growth, it is possible to determine the stripe extending direction parallel to an afterward grown GaN<1-100> direction. In the case of a sapphire undersubstrate (U 1 ), trains of dots should be formed to be parallel to sapphire <11-20> directions. In the case of a GaAs(111) undersubstrate (U 2 ), trains of dots should be formed to be parallel to GaAs <11-2> directions.
[0132] In the example, the dot is a round. The diameter of a dot is t=50 μm. The pitch is p=300 μm. The distance between neighboring dots is f=250 μm. Unit regular triangle having dots at corners has an area of 38971 μm 2 . Area of a dot is 1963 μm 2 . The area ratio of the exposed parts to covered parts is 19:1. Three kinds of undersubstrate U 1 , U 2 and U 3 and two kinds of mask M 1 and M 2 make six kinds of masked undersubstrate M 1 U 1 , M 1 U 2 , M 1 U 3 , M 2 U 1 , M 2 U 2 and M 2 U 3 .
[0000] [3. Inversion Region Generating Temperature Tj]
[0133] The growing temperature for producing the orientation inversion regions on masks is denoted by “Tj”. This is otherwise called a “first growth temperature ” Tj. Embodiment 1 tries to make the on-mask inversion regions at seven different temperatures Tj 1 to Tj 7 . Tj 1 =850, Tj 2 =900, Tj 3 =920, Tj 4 =950, Tj 5 =970, Tj 6 =990 and Tj 7 =1150. Six kinds of masked undersubstrates and seven different temperatures produce 42 different specimens.
[0000] [4. Other Conditions for Growth (Buffer Layer Formation)]
[0134] The masked undersubstrates (U 1 , U 2 , U 3 ; M 1 , M 2 ) are inputted into a HVPE furnace and are placed on a susceptor. The susceptor and specimens are heated to about 500. At an initial step, GaN buffer layers are grown upon the masked undersubstrates at a low temperature of about Tb=500 under ammonia partial pressure P NH3 =0.2 atm (20 kPa) and hydrochloride partial pressure P HCl =2×10 −3 atm (0.2 kPa). The time of forming the GaN buffer layers is 15 minutes. The thickness of the GaN buffer layers is about 60 nm.
[0135] Then each set of six kind susceptor/specimens is heated up to a predetermined first growth temperature of Tj 1 to Tj 7 . The first growth produces orientation inversion regions on the masked parts and epitaxial layers on exposed parts. Ammonia partial pressure is P NH3 =0.2 atm (20 kPa). Hydrochloride partial pressure is P HCl =2×10 −2 atm (2 kPa). The growing time is 60 minutes. An average thickness of the grown crystals is about 70 μm. The thickness is independent of the kinds of undersubstrates U 1 , U 2 and U 3 . The growing speed is Vj=70 μm/h.
[0000] [5. Growth for Producing Inversion Regions J]
[0136] Experiments give knowledge of the situations of crystal growth of generating the 180 degree c-axis inversion regions as follows.
[0137] A series of occurrence of an inversion region J is clarified by referring to FIG. 7 ( 1 )- FIG. 7 ( 5 ). FIG. ( 1 ) denotes a part of an undersubstrate U partial coated with a mask M. Although plenty of mask dots or stripes are formed on an undersubstrate, FIG. 7 ( 1 )- FIG. 7 ( 5 ) denote only a dot or a stripe for short. The sectional view is similar for both a dotmask M 2 and a stripemask M 1 . Here FIG. 7 ( 1 )- FIG. 7 ( 5 ) mean a stripemasked specimen. The mask stripe M extends in the direction vertical to paper.
[0138] Then vapor phase GaN growth starts. GaN nuclei happen on exposed parts. No GaN nucleus appears on masks M at an initial stage. When a buffer layer is made, the height of the buffer layer is lower than that of the mask. As shown in FIG. 7 ( 2 ), on-exposed-part GaN films grow thicker on all exposed parts without overlapping the masks. The masks have a strong function of suppressing GaN growth. The GaN films have flat surfaces and slants. A slant starts from a verge of the mask and arrives at a flat surface. During further growth, the slants rise and become facets with definite angels ( FIG. 7 ( 2 )). Orientation of the facets depends upon the direction of the masks. For example, the facets F are {11-22} facets when the stripes of the mask are directed in GaN <1-100>. Masks are free from GaN grains. A pair of facets F and F confront each other across the mask M. Regions beneath the facets F are low defect density single crystal regions Z. Regions below the flat C-planes are C-plane growth regions Y. In FIG. 7 ( 2 ), GaN crystals consist of Z and Y. Z and Y are GaN single crystals epitaxially grown on exposed parts.
[0139] A sign of generating of inversion regions J is an appearance of rugged protrusions midway on inclining facets F. The slanting protrusions are called “beaks” Q. Beaks Q and Q confront each other across the mask M. When no beak appears, no inversion regions J occur on masks. The beaks are polarity inversion crystals having a 180 degree inversion c-axis. Polarity means the direction of the c-axis. Polarity inversion means that the crystal has a 180 degree inversion c-axis in comparison with the surrounding crystals (Z and Y). The upper surface of the beaks Q inclines at 25 degrees to 35 degrees to the horizontal plane. The beaks are polarity inversion crystals having a c-axis by 180 degrees inverted to the neighboring crystals Z. Since the orientation of the beaks Q is inverse, the beaks Q can be seeds of the orientation inversion regions J. When the crystal growth proceeds, rugged beaks Q grow bigger and longer. Tips of beaks Q extend and come into contact with each other above the mask M as shown in FIG. 7 ( 4 ). A pair of the beaks Q are unified and bridged across the mask. The beaks Q are not in contact with the mask M.
[0140] Following the unification of the beaks, GaN grows on the beaks Q as seeds. The GaN piling on the seeds has the same polarity as the beaks Q. Since the beaks are inversion crystals, the GaN grown on the beaks above the masks is a polarity inversion crystal. All GaN crystals grown on the beaks are orientation inversion crystals. Regions above masks are called “defect accumulating regions” H. In the case, the defect accumulating regions H are inversion regions J. GaN crystals which are taller than the inversion regions J are still grown on both exposed parts ( FIG. 7 ( 5 )). Top flat surfaces are C-planes. Slants are facets F. Crystals grown on the exposed parts contain plenty of dislocations generated at the boundaries between the undersubstrate and the grown crystals. Dislocations extend upward, accompanying the GaN growth. The present invention grows GaN crystals by making facets and keeping facets. This is the facet growth method on which the present invention relies. GaN continues to grow without burying the facets. Crystals grow in the direction parallel to the normals standing on the facets. Accompanying crystal growth, dislocations extend in the same direction as the crystal growth. Dislocation extension is parallel to the growth direction. Then directions of dislocation extension are slantingly upward from the facets.
[0141] Dislocations prolong toward defect accumulating regions H on masks. When dislocations arrive at the defect accumulating region H, the dislocations are absorbed and arrested in the defect accumulating regions H. When the defect accumulating region H is an orientation inversion regions J, the crystal orientation is inverse in the defect accumulating region H. The boundary is an orientation transition plane, which firmly arrests dislocations and prohibits once-arrested dislocations from releasing. The once-arrested dislocations never return to the regions Z below the facets. Dislocations in the facet-below regions Z irreversibly decrease. Dislocation density is decreasing during the allover crystal growth in the facet-below regions Z. Thus the facet-below regions Z on exposed parts are called “low defect density single crystal regions” Z. The facet-below regions have plenty of dislocations generated at interfaces between the regions Z and the undersubstrate U at an initial stage. The following facet growth carries dislocations from the facet-below regions Z to the on-mask defect accumulating regions H. The facet-below regions Z become low dislocation density. The facet-below regions Z are single crystals determined by the orientation of the undersubstrate U. Then it is valid to name the facet-below regions as low defect density single crystal regions Z. The facet growth continues till the end of the growth. Expelling dislocations from Z continues till the end. The single crystal regions Z become lower and lower defect density. Sometimes C-plane growth regions Y remain till the end on exposed parts. The C-plane growth regions Y become low dislocation density because dislocations diffuse to neighboring facet-below regions Z due to dislocation density gradient.
[0142] The above is the best case. On the contrary sometimes no inversion regions J are generated on masks. It is supposed that occurrence or non-occurrence of the inversion regions J on masks would depend upon the temperature Tj, the gas flow, the undersubstrate U, the mask material and so on. Embodiment 1 examines the influence of the temperature Tj upon the on-mask inversion region formation on condition of Vj=70 μm/h, P NH3 =20 kPa and P HCl =2 kPa.
[0000] [(1) In the Case of Tj 1 =850]
[0000]
Undersubstrate: sapphire(0001) wafer (U 1 ), GaAs(111) wafer (U 2 ), GaN/sapphire template (U 3 ).
Mask Pattern: Stripemask (M 1 ), Dotmask (M 2 ).
Vj=70 μm/h, P NH3 =20 kPa, P HCl =2 kPa.
Result of Observation
M 1 : stripemask: Wavy orientation inversion regions J intermittently occur on most mask stripes.
M 2 : dotmask: Orientation inversion regions J occur on most mask dots.
[(2) In the Case of Tj 2 =900]
Undersubstrate: sapphire(0001) wafer (U 1 ), GaAs(111) wafer (U 2 ), GaN/sapphire template (U 3 ).
Mask pattern: stripemask (M 1 ), dotmask (M 2 ).
Vj=70 μm/h, P NH3 =20 kPa, P HCl =2 kPa.
Result of Observation
M 1 : stripemask: Orientation inversion regions J continually occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J occur on all dots.
[(3) In the Case of Tj 3 =920]
Undersubstrate: sapphire(0001) wafer (U 1 ), GaAs(111) wafer (U 2 ), GaN/sapphire template (U 3 ).
Mask pattern: stripemask (M 1 ), dotmask (M 2 ).
Vj=70 μm/h, P NH3 =20 kPa, P HCl =2 kPa.
Result of Observation
M 1 : stripemask: Orientation inversion regions J continually occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J occur on all dots.
[(4) In the Case of Tj 4 =950]
Undersubstrate: sapphire(0001) wafer (U 1 ), GaAs(111) wafer (U 2 ), GaN/sapphire template (U 3 ).
Mask pattern: stripemask (M 1 ), dotmask (M 2 ).
Vj=70 μm/h, P NH3 =20 kPa, P HCl =2 kPa.
Result of Observation
M 1 : stripemask: Orientation inversion regions J continually occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J occur on all dots.
[(5) In the Case of Tj 5 =970]
Undersubstrate: sapphire(0001) wafer (U 1 ), GaAs(111) wafer (U 2 ), GaN/sapphire template (U 3 ).
Mask pattern: stripemask (M 1 ), dotmask (M 2 ).
Vj=70 μm/h, P NH3 =20 kPa, P HCl =2 kPa.
Result of Observation
M 1 : stripemask: Orientation inversion regions J continually occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J occur on all mask dots.
[(6) In the Case of Tj 6 =990]
Undersubstrate: sapphire(0001) wafer (U 1 ), GaAs(111) wafer (U 2 ), GaN/sapphire template (U 3 ).
Mask pattern: stripemask (M 1 ), dotmask (M 2 ).
Vj=70 μm/h, P NH3 =20 kPa, P HCl =2 kPa.
Result of Observation
M 1 : stripemask: Orientation inversion regions J continually occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J occur on all mask dots.
[(7) In the Case of Tj 6 =1150]
Undersubstrate: sapphire(0001) wafer (U 1 ), GaAs(111) wafer (U 2 ), GaN/sapphire template (U 3 ).
Mask pattern: stripemask (M 1 ), dotmask (M 2 ).
Vj=70 μm/h, P NH3 =20 kPa, P HCl =2 kPa.
Result of Observation
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Orientation inversion regions J occur on few mask dots.
[0171] The results prove that formation of the inversion regions J depends upon the first temperature Tj. At some temperatures, inversion regions J happen on all masks. At other temperatures, few mask dots or stripes are covered with inversion regions J. Formation of on-mask inversion regions J will be examined afterward by changing conditions other than temperatures. The above results demonstrate that the first temperature Tj has a great influence on the formation of on-mask inversion regions J.
[0172] Tj 7 =1150 suppresses the undersubstrates (U 1 , U 2 , U 3 ) with masks (M 1 , M 2 ) from producing orientation inversion regions J. Tj 7 =1150 is not an appropriate temperature at the growing speed Vj=70 μm/h. Tj 1 =850 and Tj 6 =990 allow all or most of the mask dots or stripes to cause inversion regions J. An appropriated scope of the inversion region formation temperatures Tj at Vj=70 μm/h is a 140 degree range between 850 and 990.
[0173] Tj 2 =900 and Tj 6 =990 allow all the masks to induce inversion regions J. A more pertinent scope of the inversion region formation temperature at Vj=70 μm/h is 900 to 990.
Embodiment 2
Dependence on Growing Speeds Vj at a Temperature of 940
[0174] Embodiment 2 uses the same HVPE growth furnace as Embodiment 1. Embodiment 2 employs stripe/dotmasked GaAs(111) undersubstrates M 1 U 2 and M 2 U 2 prepared by forming an SiO 2 stripemask M 1 or SiO 2 dotmask M 2 on GaAs(111) undersubstrates U 2 . Embodiment 2 grows GaN crystals on the stripemasked and dotmasked undersubstrates by varying the growing speed Vj at a temperature of 940. Embodiment 2 investigates relations between the growing speed Vj and the facility of forming the orientation inversion regions J at 940.
[0175] The stripe/dotmasked undersubstrates M 1 U 2 and M 2 U 2 are laid on a susceptor in the HVPE reaction furnace. At an initial step, GaN buffer layers are grown on the undersubstrates for 15 minutes at a low temperature Tb of about Tb=500 by supplying HCl and NH 3 at a NH 3 partial pressure P NH 3 =0.2 atm (20 kPa) and an HCl partial pressure P HCl =2×10 −3 atm (0.2 kPa). The thicknesses of the buffer layers are about 60 nm.
[0176] The samples on the susceptor are heated up to an inversion region formation temperature Tj=940. GaN epitaxial layers and orientation inversion regions J are grown on exposed parts and masked parts respectively. The ammonia partial pressure is maintained to be a constant P NH3 =0.2 atm (20 kPa). The hydrochloride partial pressure P HCl is varied for examining the dependence of the occurrence of inversion regions J upon P HCl .
[0000] HCl partial pressure: P HCl 1=7×10 −3 atm (0.7 kPa)
P HCl 2=1×10 −2 atm (1 kPa)
P HCl 3=1.5×10 −2 atm (1.5 kPa)
P HCl 4=2×10 −2 atm (2 kPa)
P HCl 5=3×10 −2 atm (3 kPa)
P HCl 6=4×10 −2 atm (4 kPa)
[0177] Embodiment 2 keeps the ammonia partial pressure P NH3 =0.2 atm (20 kPa) and the temperature Tj=940 and changes the hydrochloride partial pressure P HCl . When the HCl partial pressure P HCl is changed, the growing speed Vj is varied. Enhancement of the HCl partial pressure P HCl raises the growing speed Vj. Variations of occurrence of orientation inversion regions J contingent on the growing speed Vj are examined.
[0000] (1) In the Case of P HCl 1=7×10 −3 atm (0.7 kPa)
[0178] Growing speed Vj1=18 μm/h
[0179] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=940.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Few mask dots carry orientation inversion regions J.
(2) In the Case of P HCl 2=1×10 −2 atm (1 kPa)
[0182] Growing speed Vj2=32 μm/h
[0183] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=940.
[0000] Result of Observation
[0000]
M 1 : stripemask: Intermittent orientation inversion regions J discontinuously occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on most of the dots.
(3) In the Case of P HCl 3=1.5×10 −2 atm (1.5 kPa)
[0186] Growing speed Vj3=48 μm/h
[0187] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=940.
[0000] Result of Observation
[0000]
M 1 : stripemask: Continual orientation inversion regions J occur all on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on all of the dots.
(4) In the Case of P HCl 4=2×10 −2 atm (2 kPa)
[0190] Growing speed Vj4=70 μm/h
[0191] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=940.
[0000] Result of Observation
[0000]
M 1 : stripemask: Continual orientation inversion regions J occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on all of the dots.
(5) In the Case of P HCl 5=3×10 −2 atm (3 kPa)
[0194] Growing speed Vj5=102 μm/h
[0195] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=940.
[0000] Result of Observation
[0000]
M 1 : stripemask: Continual orientation inversion regions J occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on all of the dots.
(6) In the Case of P HCl 6=4×10 −2 atm (4 kPa)
[0198] Growing speed Vj6=138 μm/h
[0199] Undersubstrate=GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=940.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on few dots.
[0202] The above observation teaches us the following facts. Occurrence of c-axis inversion regions J depends upon the growing speed Vj. A slower growing speed than 18 μm/h suppresses orientation inversion regions J from happening. A faster growing speed than 138 μm/h also suppresses orientation inversion regions J from occurring.
[0203] An optimum growing speed Vj for producing orientation inversion regions J on masks ranges from 25 μm/h to 120 μm/h at 940. The lowest limit 25 μm/h and the highest limit 120 μm/h are calculated by averaging the marginal appropriate speeds of making sufficient orientation inversion regions J and the neighboring inappropriate speeds of inducing few inversion regions J.
Embodiment 3
Dependence on Growing Speeds at a Temperature of 1030
[0204] Repetitions of trials of Embodiments 1 and 2 suggest the inventors that the facility of inducing inversion regions J depends strongly upon the temperature Tj firstly and depends upon the growing speeds Vj at the temperature Tj secondarily. Embodiment 3 investigates dependence of inversion region occurrence upon growing speeds at a temperature of 1030 higher than Embodiment 2 (940).
[0205] Embodiment 3 uses the same HVPE growth furnace as Embodiment 1. Embodiment 3 employs stripe/dotmasked GaAs(111) undersubstrates M 1 U 2 and M 2 U 2 prepared by forming an SiO 2 stripemask M 1 or an SiO 2 dotmask M 2 on GaAs(111) undersubstrates U 2 . Embodiment 3 grows GaN crystals on the stripemasked and dotmasked undersubstrates by varying the growing speed at a temperature of 1030 different from Embodiment 2 (940). Embodiment 3 investigates relations between the growing speed and the facility of forming the orientation inversion regions J at 1030.
[0206] The stripe/dotmasked undersubstrates M 1 U 2 and M 2 U 2 are laid on a susceptor in the HVPE reaction furnace. At an initial step, GaN buffer layers are grown on the undersubstrates for 15 minutes at a low temperature of about 500 by supplying HCl and NH 3 at a NH 3 partial pressure P NH3 =0.2 atm (20 kPa) and an HCl partial pressure P HCl =2×10 −3 atm (0.2 kPa). Thicknesses of the buffer layers are about 60 nm.
[0207] The samples on the susceptor are heated up to an inversion region formation temperature of Tj=1030. GaN epitaxial layers and orientation inversion regions J are grown on exposed parts and masked parts respectively. The ammonia partial pressure is maintained to be a constant P NH3 =0.2 atm (20 kPa). The hydrochloride partial pressure P HCl is varied for examining the dependence of the occurrence of inversion regions J upon P HCl .
[0000] HCl partial pressure: P HCl 1=7×10 −3 atm (0.7 kPa)
P HCl 2=1×10 −2 atm (1 kPa)
P HCl 3=1.5×10 −2 atm (1.5 kPa)
P HCl 4=2×10 −2 atm (2 kPa)
P HCl 5=4×10 −2 atm (4 kPa)
P HCl 6=6×10 −2 atm (6 kPa)
P HCl 7=8×10 −2 atm (8 kPa)
[0208] Although the ammonia (NH 3 ) partial pressure P NH3 is constant, the growing speed is changed by varying the hydrochloride (HCl) partial pressure P HCl . An increase of the HCl partial pressure enhances the growing speed Vj. Embodiment 3 examines the dependence of appearance of the inversion regions J upon the growing speed Vj.
[0000] (1) In the Case of P HCl 1=7×10 −3 atm (0.7 kPa)
[0209] Growing speed Vj1=22 μm/h
[0210] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=1030.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Few mask dots carry orientation inversion regions J.
(2) In the Case of P HCl 2=1×10 −2 atm (1 kPa)
[0213] Growing speed Vj2=38 μm/h
[0214] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=1030.
[0000] Result of Observation
[0000]
M 1 : stripemask: Intermittent orientation inversion regions J discontinuously occur on few mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on few dots.
(3) In the Case of P HCl 3=1.5×10 −2 atm (1.5 kPa)
[0217] Growing speed Vj3=62 μm/h
[0218] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=1030.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J intermittently occur all on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on most of the dots.
(4) In the case of P HCl 4=2×10 −2 atm (2 kPa)
[0221] Growing speed Vj4=85 μm/h
[0222] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=1030.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J intermittently occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on most of the dots.
(5) In the Case of P HCl 5=4×10 −2 atm (4 kPa)
[0225] Growing speed Vj5=132 μm/h
[0226] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=1030.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J intermittently occur on all mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on most of the dots.
(6) In the Case of P HCl 6=6×10 −2 atm (6 kPa)
[0229] Growing speed Vj6=158 μm/h
[0230] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=1030.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J intermittently occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on most of the dots.
(7) In the Case of P HCl 7=8×10 −2 atm (8 kPa)
[0233] Growing speed Vj7=236 μm/h
[0234] Undersubstrate=GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=1030.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on few dots.
[0237] The above results show the inversion region occurrence dependence upon the growing speed Vj. It is again confirmed that the change of the growing speed Vj varies the occurrence of the c-axis inversion regions J. However, it is noticed that Embodiment 3, which grows GaN at Tj=1030, has inversion region appearance dependence upon the growing speed Vj which differs from Embodiment 2 growing GaN at Tj=940. In Embodiment 3 with a high temperature of Tj=1030, low growing speeds less than 38 μm/h suppress inversion regions J from happening on masks. Even a high growing speed of 158 μm/h allows many orientation inversion regions J to happen on masks. Further high growing speeds more than 236 μm/h decrease occurrence of on-mask orientation inversion regions J in Embodiment 3 of Tj=1030.
[0238] At a growing temperature of Tj=1030, an appropriate growing speed range of producing orientation inversion regions J is from 50 μm/h and 197 μm/h. It is confirmed that the pertinent growing speed range (50-197 μm/h) at Tj=1030 (Embodiment 3) is upward shifted from the appropriate growing speed range (25-120 μm/h) at Tj=940 (Embodiment 2).
Embodiment 4
Inversion Region Occurrence Dependence Upon Growing Speed Vj at a Temperature of Tj=960
[0239] Embodiment 3 has clarified an appropriate growing speed range for inducing orientation inversion regions on masks at 1030. Embodiments 1 and 2 suggest that lower temperatures than 1030 are more pertinent for making orientation inversion regions J on all masks. Therefore Embodiment 4 investigates the relation between the growing speed Vj and the inversion region occurrence facility at a low temperature close to 940 of Embodiment 2.
[0240] Embodiment 4 uses the same HVPE growth furnace as Embodiment 1. Embodiment 3 employs stripe/dotmasked GaAs(111) undersubstrates M 1 U 2 and M 2 U 2 prepared by forming an SiO 2 stripemask M 1 or an SiO 2 dotmask M 2 on GaAs(111) undersubstrates U 2 . Embodiment 4 grows GaN crystals on the stripemasked and dotmasked undersubstrates by varying the growing speed at temperatures different from Embodiment 2. Embodiment 4 investigates relations between the growing speed and the facility of forming the orientation inversion regions J.
[0241] The stripe/dot-masked GaAs undersubstrates (M 1 U 2 , M 2 U 2 ) are placed upon a susceptor in the HVPE furnace. At an initial stage, Embodiment 4 makes GaN buffer layers on the undersubstrate (M 1 U 2 , M 2 U 2 ) for 15 minutes at a low temperature Tb of about Tb=500 under an ammonia partial pressure P NH3 =0.2 atm (20 kPa) and a hydrochloride partial pressure P HCl =2×10 −3 (0.2 kPa). The thickness of the GaN buffer layers is about 60 nm.
[0242] Embodiment 4 heats the susceptor and specimens up to an inversion region formation temperature Tj of Tj=960. The ammonia partial pressure is maintained to be a constant P NH3 =0.2 atm (20 kPa). The hydrochloride partial pressure P HCl is varied for examining how on-mask occurrence of orientation inversion regions J changes as a function of P HCl .
[0000] HCl partial pressure: P HCl 1=7×10 −3 atm (0.7 kPa)
P HCl 2=1×10 −2 atm (1 kPa)
P HCl 3=1.5×10 −2 atm (1.5 kPa)
P HCl 4=2×10 −2 atm (2 kPa)
P HCl 5=2.5×10 −2 atm (2.5 kPa)
P HCl 6=3×10 −2 atm (3 kPa)
P HCl 7=4×10 −2 atm (4 kPa)
[0243] Maintaining P NH3 =0.2 atm (20 kPa), Embodiment 4 changes the growing speed by varying the hydrochloride partial pressure P HCl . An increase of the hydrochloride partial pressure P HCl raises the growing speed Vj. Embodiment 4 inspects how the occurrence of orientation inversion regions J depends upon the growing speed Vj.
[0000] (1) In the Case of P HCl 1=7×10 −3 atm (0.7 kPa)
[0244] Growing speed Vj1=20 μm/h
[0245] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=960.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Few mask dots carry orientation inversion regions J.
(2) In the Case of P HCl 2=1×10 −2 atm (1 kPa)
[0248] Growing speed Vj2=28 μm/h
[0249] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=960.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Few mask dots carry orientation inversion regions J.
(3) In the Case of P HCl 3=1.5×10 −2 atm (1.5 kPa)
[0252] Growing speed Vj3=42 μm/h
[0253] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=960.
[0000] Result of Observation
[0000]
M 1 : stripemask: Intermittent orientation inversion regions J dottedly occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on most of the mask dots.
(4) In the Case of P HCl 4=2×10 −2 atm (2 kPa)
[0256] Growing speed Vj4=65 μm/h
[0257] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=960.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J continually occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on all mask dots.
(5) In the Case of P HCl 5=2.5×10 −2 atm (2.5 kPa)
[0260] Growing speed Vj5=110 μm/h
[0261] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=960.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J continually occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on every mask dot.
(6) In the Case of P HCl 6=3×10 −2 atm (3 kPa)
[0264] Growing speed Vj6=130 μm/h
[0265] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=960.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J intermittently occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on most mask dots.
(7) In the Case of P HCl 7=4×10 −2 atm (4 kPa)
[0268] Growing speed Vj7=150 μm/h
[0269] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=960.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on few mask dots.
[0272] The above results teach us that a change of the growing speed Vj varies the occurrence of the c-axis inversion regions J.
[0273] The dependence of the occurrence of the orientation inversion regions J upon the growing speed Vj at Tj=960 is different from the case of Tj=940 (Embodiment 2). Embodiment 4 grows GaN at a temperature 20 degrees higher than Embodiment 2. In Embodiment 4, a low growing speed of 42 μm/h invites orientation inversion regions almost all of the masks (M 1 , M 2 ). But growing speeds lower than 28 μm/h suppress orientation inversion regions from happening. In Embodiment 4, high growing speed of Vj6=130 μm/h causes sufficient orientation inversion regions J on masks. Further high growing speed of Vj7=150 μm/h is too fast to make enough orientation inversion regions J on masks.
[0274] An appropriate range at Tj=960 of inviting c-axis inversion regions on masks is 35 μm/h to 140 μm/h. The marginal values (35, 140 μm/h) are determined by averaging the speed causing sufficient inversion regions J on most masks and the speed making poor inversion regions on few masks. The appropriate range (35 μm/h-140 μm/h) at Tj=960 (Embodiment 4) is slightly higher than the appropriate range (25 μm/h-120 μm/h) at Tj=940 (Embodiment 2).
[0275] At 960 (Embodiment 4), growing speeds Vj4=65 μm/h and Vj5=110 μm/h yield sufficient inversion regions J on all masks. The results show that Tj=960 (Embodiment 4) is stronger than Tj=1030 (Embodiment 3) in causing inversion regions J.
Embodiment 5
Inversion Region Occurrence Dependence Upon Growing Speed Vj at a Temperature of Tj=920
[0276] Embodiments 2, 3 and 4 have clarified an appropriate growing speed range for inducing orientation inversion regions on masks at 940, 1030 and 960 respectively. Embodiment 5 investigates the relation between the growing speed Vj and the inversion region occurrence facility at a temperature Tj=920 close to 940 of Embodiment 2.
[0277] Embodiment 5 uses the same HVPE growth furnace as Embodiment 1. Embodiment 5 employs stripe/dotmasked GaAs(111) undersubstrates M 1 U 2 and M 2 U 2 prepared by forming an SiO 2 stripemask M 1 or an SiO 2 dotmask M 2 on GaAs(111) undersubstrates U 2 . Embodiment 5 grows GaN crystals on the stripemasked and dotmasked undersubstrates by varying the growing speed at a temperatures of 920. Embodiment 5 investigates relations between the growing speed and the facility of forming the orientation inversion regions J at 920.
[0278] The stripe/dot-masked GaAs undersubstrates (M 1 U 2 , M 2 U 2 ) are placed upon a susceptor in the HVPE furnace. At an initial stage, Embodiment 5 makes GaN buffer layers on the undersubstrate (M 1 U 2 , M 2 U 2 ) for 15 minutes at a low temperature Tb of about Tb=500 under an ammonia partial pressure P NH3 =0.2 atm (20 kPa) and a hydrochloride partial pressure P HCl =2×10 −3 (0.2 kPa). The thickness of the GaN buffer layers is about 60 nm.
[0279] Embodiment 5 heats the susceptor and specimens up to an inversion region formation temperature Tj of Tj=920. The ammonia partial pressure is maintained to be a constant P NH3 =0.2 atm (20 kPa). The hydrochloride partial pressure P HCl is varied for examining how on-mask occurrence of orientation inversion regions J changes as a function of P HCl .
[0000] HCl partial pressure: P HCl 1=7×10 −3 atm (0.7 kPa)
P HCl 2=1×10 −2 atm (1 kPa)
P HCl 3=1.5×10 −2 atm (1.5 kPa)
P HCl 4=2×10 −2 atm (2 kPa)
P HCl 5=4×10 −2 atm (4 kPa)
P HCl 6=5×10 −2 atm (5 kPa)
[0280] Maintaining P NH3 =0.2 atm (20 kPa) and Tj=920, Embodiment 5 changes the growing speed by varying the hydrochloride partial pressure P HCl . Increase of the hydrochloride partial pressure P HCl raises the growing speed Vj. Embodiment 5 inspects how the occurrence of orientation inversion regions J depends upon the growing speed Vj.
[0000] (1) In the Case of P HCl 1=7×10 −3 atm (0.7 kPa)
[0281] Growing speed Vj1=14 μm/h
[0282] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=920.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Few mask dots carry orientation inversion regions J.
(2) In the Case of P HCl 2=1×10 −2 atm (1 kPa)
[0285] Growing speed Vj2=36 μm/h
[0286] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=920.
[0000] Result of Observation
[0000]
M 1 : stripemask: Continual orientation inversion regions J occur on mask stripes.
M 2 : dotmask: All mask dots carry orientation inversion regions J.
(3) In the Case of P HCl 3=1.5×10 −2 atm (1.5 kPa)
[0289] Growing speed Vj3=55 μm/h
[0290] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=920.
[0000] Result of Observation
[0000]
M 1 : stripemask: Continual orientation inversion regions J occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on all of the mask dots.
(4) In the Case of P HCl 4=2×10 −2 atm (2 kPa)
[0293] Growing speed Vj4=75 μm/h
[0294] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=920.
[0000] Result of Observation
[0000]
M 1 : stripemask: Continual orientation inversion regions J occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on all mask dots.
(5) In the Case of P HCl 5=4×10 −2 atm (4 kPa)
[0297] Growing speed Vj5=110 μm/h
[0298] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=920.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J intermittently occur on mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on all mask dots.
(6) In the Case of P HCl 6=5×10 −2 atm (5 kPa)
[0301] Growing speed Vj6=130 μm/h
[0302] Undersubstrate: GaAs wafer(U 2 ), P NH3 =20 kPa, Tj=920.
[0000] Result of Observation
[0000]
M 1 : stripemask: Orientation inversion regions J occur on few mask stripes.
M 2 : dotmask: Orientation inversion regions J appear on few mask dots.
[0305] The above results teach us that the change of the growing speed Vj varies the occurrence of the c-axis inversion regions J.
[0306] The dependence of the occurrence of the orientation inversion regions J upon the growing speed Vj at Tj=920 (Embodiment 5) is different from the case of Tj=940 (Embodiment 2). Embodiment 5 grows GaN at a temperature 20 degrees lower than Embodiment 2. In Embodiment 5, a low growing speed of 36 μm/h invites orientation inversion regions onto all of the masks (M 1 , M 2 ). But growing speeds lower than 14 μm/h suppress orientation inversion regions from happening. In Embodiment 5, high growing speed of Vj5=110 μm/h causes sufficient orientation inversion regions J on masks. Further high growing speed of Vj6=130 μm/h is too fast to make enough orientation inversion regions J on masks.
[0307] An appropriate range of inviting c-axis inversion regions on masks is 25 μm/h to 120 μm/h (Embodiment 5) at Tj=920. The marginal values (25, 120 μm/h) are determined by averaging the speed causing sufficient inversion regions J on most masks and the speed making poor inversion regions on few masks. The appropriate range (25 μm/h-120 μm/h) at Tj=920 (Embodiment 5) is slightly lower than the appropriate range (35 μm/h-140 μm/h) at Tj=960 (Embodiment 4).
[0308] At 920 (Embodiment 5), growing speeds Vj=36 μm/h, 55 μm/h and 77 μm/h yield sufficient inversion regions J on all masks. The results show that Tj=920 (Embodiment 5) is more effective than Tj=1030 (Embodiment 3) in causing inversion regions J.
Embodiment 6
Thick GaN Crystal Growth at Te=1050 Succeeding Inversion Regions Formation
[0309] Embodiments 1, 2, 3, 4 and 5 grow the inversion regions J on masks and epitaxial GaN crystals on exposed parts in the first growth. The purpose of the first growth is to make the orientation inversion regions J on masks as defect accumulating regions H. The second growth denotes thick GaN crystal growth succeeding the first growth. Embodiment 6, which grows thick GaN crystals, includes the first growth and the second growth. Embodiment 6 employs the same HVPE furnace as Embodiment 1. Embodiment 6 adopts a sapphire (0001) single crystal wafers U 1 as undersubstrates.
[0310] A dotmask M 2 ( FIG. 10 ( 1 )) is formed on a sapphire undersubstrate U 1 . A stripemask M 1 ( FIG. 8 ( 1 )) is formed on another sapphire undersubstrate U 1 . Then two kinds of masked undersubstrates M 1 U 1 and M 2 U 1 are prepared. The buffer layer formation and the first growth are done on the masked undersubstrates M 1 U 1 and M 2 U 1 of Embodiment 6.
[0311] The masked undersubstrates are placed upon a susceptor in the HVPE reaction furnace. At an initial step, Embodiment 6 grows GaN buffer layers for 15 minutes at a low temperature of about Tb=500 at P NH3 =0.2 atm (20 kPa) and P HCl =2×10 −3 atm (0.2 kPa). The ammonia/hydrochloride ratio is P NH3 /P HCl =100 at the buffer layer growth step. The thickness of the buffer layers is about 60 nm.
[0312] The susceptor and specimens are heated up to a first growth temperature Tj=950 for producing orientation inversion regions J on masks. At the first growth, Embodiment 6 grows GaN on the undersubstrates M 1 U 1 and M 2 U 1 at Tj=950, P NH3 =0.2 atm (20 kPa) and P HCl =2×10 −2 atm (2 kPa) for 45 minutes for making inversion regions J on masks and GaN crystals on exposed parts. The ammonia/hydrochloride ratio is P NH3 /P HCl =10 at the first growth step for making inversion regions J.
[0313] Following the inversion region formation, Embodiment 6 grows epitaxial thick GaN crystals on the GaN/mask/undersubstrates at a second growth temperature of Te=1050, P N H3 =0.2 atm (20 kPa) and P HCl =3×10 −2 atm (3 kPa). The ammonia/hydrochloride ratio is P NH3 /P HCl =6.7 at the second growth step for making thick GaN crystals. The growth time is 15 hours. Embodiment 6 cools the furnace, takes specimens out of the furnace and obtains 1.5 mm thick GaN crystals.
[0314] The GaN crystals are observed by a stereoscopic microscope and a scanning electron microscope (SEM). On-dotmask grown GaN crystals have dotted cavities just above the mask dots. On-stripemask grown GaN crystals have shallow parallel cavities just on the mask stripes. The positions of the cavities correctly correspond to the positions of the masks. The cavities are composed of facets. There are other shallower facets at the bottoms of the cavities.
[0315] Embodiment 6 removes the sapphire undersubstrates (U 1 ) by grinding and obtains freestanding GaN substrates. Surfaces of the freestanding GaN crystals are ground and polished into both-surface mirror flat GaN wafers ( FIG. 9 ( 4 )). The GaN crystals are transparent for visible light. The GaN crystals look like a uniform glass for human eye sight. Human eye sight cannot discern inner structures of the GaN crystals.
[0316] Embodiment 6 observes surfaces of the polished stripemask/dotmask-grown GaN substrates by an optical microscope and cathode luminescence (CL).
[0317] It is confirmed that the on-stripemask GaN substrates have parallel cavities with a 20 μm width regularly aligning at a 300 μm pitch. This corresponds to the stripemask (s=30 μm, p=300 μm) with accuracy. The cavities originate from the occurrence of {11-2-6} facets on masks. The existence of {11-2-6} facets on masks proves that the on-mask regions are orientation inversion regions J. The CL observation demonstrates that the on-stripemask GaN substrates have an HZYZHZYZ . . . structure as shown in FIG. 8 ( 2 ). It is confirmed that defect accumulating regions H are generated on mask stripes and the defect accumulating regions H are orientation inversion regions J.
[0318] The optical microscope observes that cavities with a diameter of 30 μm to 40 μm appear at spots aligning at a 300 μm pitch in six fold symmetry on the on-dotmask (M 2 ) GaN substrates. The positions of the cavities correspond to the spots of mask dots (t=50 μm, p=300 μm). The on-dotmask GaN substrate reveals a concentric HZY-structure composed of defect accumulating regions H, low defect density single crystal regions Z and a C-plane growth region Y.
[0319] The CL sees a defect accumulating region H as a dark spot. Threading dislocation density is measured by counting dark spots in a definite area on a CL image. The defect accumulating regions H have a high threading dislocation density of about 10 7 cm −2 to about 10 8 cm −2 . The low defect density single crystal regions Z sandwiched between neighboring defect accumulating regions H and H have a low threading dislocation density of about 1×10 5 cm −2 .
[0000] It is confirmed that the crystal regions held between defect accumulating regions H are single crystals Z enjoying sufficiently low defect density. The produced GaN substrates are non-uniform substrates composed of H, Z and Y.
[0320] The present invention enables device makers to fabricate laser diodes on the low defect density single crystal regions Z. The present invention succeeds in making low defect density GaN substrates capable of producing laser diodes of high quality. The GaN substrates do not have uniformly low defect density. The GaN substrates of the present invention have both narrow defect accumulating regions H and wide low defect density single crystal regions Z. The present invention serves excellent GaN substrates suitable for producing photodevices of high quality.
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The facet growth method grows GaN crystals by preparing an undersubstrate, forming a dotmask or a stripemask on the undersubstrate, growing GaN in vapor phase, causing GaN growth on exposed parts, suppressing GaN from growing on masks, inducing facets starting from edges of the masks and rising to tops of GaN crystals on exposed parts, maintaining the facets, making defect accumulating regions H on masked parts. attracting dislocations into the defect accumulating regions H on masks and reducing dislocation density of the surrounding GaN crystals on exposed parts. The defect accumulating regions H on masks have four types. The best of the defect accumulating regions H is an inversion region J. Occurrence of the inversion regions J requires preceding appearance of beaks with inversion orientation on the facets. Sufficient inversion regions J are produced at an initial stage by maintaining the temperature Tj at 900° C. to 990° C. without fail. Allowable inversion regions J beaks are produced at an initial stage by the sets of temperatures T(K) and growing speeds Vj (μm/h) satisfying −4.39×10 5 /T+3.87×10 2 <Vj<−7.36×10 5 /T+7.37×10 2 .
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BACKGROUND
[0001] 1. Technical Field
[0002] The present invention relates to an image inspecting device that performs an appearance inspection using an image.
[0003] 2. Related Art
[0004] An image inspecting device that performs an appearance inspection using an image is widely used for the purpose of automation and labor-saving of an inspection in a production line. There are various kinds and techniques of the appearance inspection. In a basic configuration of the appearance inspection, an image of an inspection object is taken with an image sensor (camera), a portion constituting an inspection area is extracted from the obtained image, and a feature of the image of the inspection area portion is analyzed and evaluated to perform an intended inspection (such as non-defective or defective determination, sorting, and information acquisition).
[0005] In this kind of image inspecting device, it is necessary to perform preparation work such as setting of the inspection area prior to inspection processing. A tool dedicated to the setting of the inspection area is prepared in a general device, and a user can properly set the inspection area according to an inspection object or an inspection purpose using the tool. However, the conventional tool has only a function of defining the inspection area using simple graphics such as a circle and a rectangle and a combination thereof.
[0006] Accordingly, in the case that the inspection object has a complicated or special shape, sometimes the inspection area cannot correctly be matched with a contour of the inspection object. Even in the case that the contour of the inspection object can be expressed by the combination of the simple graphics, it takes a lot of time and workload to set the inspection area as the number of combined graphics increases. Nowadays there is a strong need to shorten arrangement time as much as possible for improvement of efficiency in multikind and small-quantity production. Therefore, it is undesirable to take a lot of trouble to set the inspection area. At the same time, in order to meet a complicated product shape and sophisticated and diversified inspection content, or in order to improve accuracy and reliability of the inspection, there is also a strong need to correctly set the inspection area only to a portion to be inspected.
[0007] Conventionally, an inspection area extracting technique in which binarization or color gamut extraction is used is well known as a technique of automatically setting the inspection area. In the inspection area extracting technique, a pixel group corresponding to a previously-set brightness range or color gamut is extracted from the image, and the pixel group is set to the inspection area. The inspection area extracting technique is effectively used in the case of a high brightness or color contrast between a portion (foreground) to be extracted as the inspection area and other portions (background). For example, the inspection area extracting technique is used in processing of extracting only an article portion from an image of an article conveyed on a belt conveyer.
[0008] A correct foreground portion is difficult to be solely extracted by the binarization or the color gamut extraction, when shade and shadow exist in the foreground portion to be extracted as the inspection area due to an influence of lighting, when the foreground portion is constructed with various kinds of brightness or colors, or when a color close to the foreground portion exists in the background. Nowadays, with the progress of the sophistication and diversification of the inspection content, frequently there is few color difference between the background and the foreground. The inspection directed only to one of cutting surfaces of a component having subjected to a forming-process and the inspection directed only to one of components mounted on a printed board can be cited as an example of few color difference between the background and the foreground. Because the binarization or the color gamut extraction is performed in each pixel of the image, the binarization or the color gamut extraction is easily influenced by a noise or a variation in lighting, and some pixel may be missing in the extracted inspection area or may be unnecessarily selected from the background like an enclave, which results in inspection accuracy being degraded.
[0009] Patent Document 1 discloses the inspection area setting methods such as a method for setting a position or a size of the inspection area from CAD data of an inspection object component and a method for recognizing an area to be inspected by taking a difference between two images taken before and after component mounting. Although the use of these inspection area setting methods can automatically set the inspection area, the inspection area setting methods lack versatility because application targets of the inspection area setting methods are restricted.
Patent Document
[0000]
Patent Document 1: Japanese Unexamined Patent Publication No. 2006-58284
Non-Patent Document
[0000]
Non-Patent Document 1: Y. Boykov and M.-P. Jolly: “Interactive Graph Cuts for Optimal Boundary & Region Segmentation of Objects in N-D images”, ICCV2001, 01, p. 105 (2001)
SUMMARY
[0012] One or more embodiments of the present invention provides a technology of being able to simply and accurately set the inspection area even when the object has the complicated or special shape or when the color of the foreground is possibly confused with the color of the background.
[0013] According to one or more embodiments of the present invention, an optimal solution of the inspection area is searched by comprehensively evaluating color or brightness information and edge information with respect to the sample image of the inspection object, thereby automatically or semi-automatically setting the inspection area.
[0014] Specifically, an inspection area setting method for setting inspection area-defining information defining an inspection area to an image inspecting device, the image inspecting device being configured to extract a portion constituting the inspection area as an inspection area image from an original image obtained by taking an image of an inspection object, and to inspect the inspection object by analyzing the inspection area image, the inspection area setting method includes: an acquisition step in which a computer acquires a sample image obtained by taking an image of a sample of the inspection object; an inspection area searching step in which the computer obtains an optimal solution of the inspection area from a plurality of candidate areas by evaluating both pixel separation and edge overlap with respect to the plurality of candidate areas that are of candidate solutions of the inspection area based on information on color or brightness of each pixel in the sample image and information on an edge included in the sample image, the pixel separation being a degree of separation of the color or the brightness between an inside and an outside of each candidate area, the edge overlap being an overlap degree between an contour of each candidate area and the edge in the sample image; and a setting step in which the computer sets inspection area-defining information defining a position and a shape in the image of the inspection area obtained in the inspection area searching step to the image inspecting device.
[0015] According to the configuration, the position and the shape of the inspection area are decided by the optimal solution search in which the sample image is used. Therefore, compared with the conventional technique in which the inspection area is manually input using the simple graphics, the complicated or special shape can be dealt with while the setting time and the workload are significantly reduced. Additionally, both the pixel separation of the color or brightness between the inside and the outside of the inspection area and the edge overlap of the contour of the inspection area are comprehensively evaluated using the information on the edge in addition to the information on the color or the brightness, so that the area extraction accuracy can be improved compared with the conventional techniques such as the binarization and the color gamut extraction.
[0016] According to one or more embodiments of the present invention, the inspection area setting method further includes a parameter receiving step in which the computer receives input of a parameter from a user. In the inspection area setting method, every time the computer receives the input of the parameter from the user in the parameter receiving step, the computer performs the inspection area searching step with the input parameter as a constraint condition to recalculate the optimal solution of the inspection area, and displays the recalculated inspection area on a display device.
[0017] According to the configuration, the user can easily check whether the desired area is selected as the inspection area by seeing the inspection area displayed on the display device. For an improper inspection area, the recalculation result is instantly checked on the screen while the parameter is properly adjusted, so that the desired inspection area can easily be narrowed down.
[0018] According to one or more embodiments of the present invention, in the parameter receiving step, the user inputs a balance parameter as one kind of the parameter in order to adjust a balance between the pixel separation and the edge overlap, and in the inspection area searching step, weight are adjusted in evaluating the pixel separation and the edge overlap according to the balance parameter input from the user.
[0019] Even for the image in which the automatic cutting between the foreground and the background is hardly performed, the user adjusts the balance parameter, whereby the desired inspection area can simply be set in a short time.
[0020] According to one or more embodiments of the present invention, a value obtained by evaluating a likelihood of a foreground of the color or the brightness of each pixel inside the candidate area with respect to representative color or representative brightness of the foreground, a value obtained by evaluating a likelihood of a background of the color or the brightness of each pixel outside the candidate area with respect to representative color or representative brightness of the background, or a value obtained by synthesizing both the values is used as the pixel separation in the inspection area searching step.
[0021] According to the configuration, the pixel separation is evaluated to be high with increasing likelihood of the foreground of the pixel inside the inspection area and with increasing likelihood of the background of the pixel outside inspection area. The color or the brightness is decided as the representative of the foreground or the background, and the inspection area is searched based on the representative color or brightness. Therefore, a potential to reach an adequate solution can dramatically be enhanced. All or some of the pixels inside the candidate area may be used in calculating a value used to evaluate the likelihood of the foreground. Similarly, all or some of the pixels outside the candidate area may be used in calculating a value used to evaluate the likelihood of the background.
[0022] According to one or more embodiments of the present invention, in the inspection area searching step, the weight is adjusted in evaluating the pixel separation and the edge overlap such that the weight of the pixel separation increases with increasing difference between the representative color or the representative brightness of the foreground and the representative color or the representative brightness of the background, and such that the weight of the edge overlap increases with decreasing difference.
[0023] In the configuration, the user does not adjust the balance parameter, but the balance parameter is automatically adjusted to a proper value. Therefore, the potential to reach the adequate solution can be enhanced even in the absence of user aid.
[0024] In the parameter receiving step, when the user inputs the representative color or the representative brightness of the foreground, the background, or the both as one kind of the parameter, a potential to reach an adequate solution can further be enhanced.
[0025] At this point, according to one or more embodiments of the present invention, in the parameter receiving step, the sample image is displayed on the display device, the user designates a portion to be the foreground or the background on the displayed sample image, and the color or the brightness of the designated portion is acquired as the representative color or the representative brightness. According to the configuration, the representative color or brightness can easily and certainly be designated.
[0026] Any parameter may be provided as long as the parameter has an influence on the optimal solution search of the inspection area. For example, information expressing a feature such as the shape and the size of the inspection area, a position of the inspection area in the image, and a texture, a topology, an adjacent element, and an inclusive element of the inspection area may be provided as the parameter, and the solution of the inspection area may be searched such that a degree of similarity between the feature of the inspection area and the feature expressed by the parameter increases in addition to the pixel separation and the edge overlap. Thus, the potential to reach the adequate solution can further be enhanced by setting various features of the inspection area to a constraint condition.
[0027] It is conceivable that sometimes the adjustment of the parameter is not sufficient to obtain a desired inspection area, or that sometimes the adjustment of the parameter takes a long time for trial and error of the parameter. Therefore, according to one or more embodiments of the present invention, the inspection area setting method further includes an inspection area correcting step of displaying the inspection area obtained in the inspection area searching step on the display device and of correcting the shape of the inspection area according to a correction instruction input from the user. When the shape of the inspection area can be corrected, the portion that is hardly automatically extracted by the computing machine can be complemented by the user aid, and therefore the optimal inspection area can easily be obtained in a short time.
[0028] Various manipulation systems are conceivable to be used for correcting the inspection area. For example, a whole or a part of the contour of the inspection area may be approximated using a path of a Bezier curve or a spline curve and the user may correct the path. Therefore, the contour of the inspection area can easily be corrected to a desired shape. According to one or more embodiments of the present invention, the user draws a free curve, and the free curve and the inspection area are synthesized such that the free curve constitutes a part of the contour of the inspection area. According to one or more embodiments of the present invention, the user designates an interval of a part of the contour of the inspection area, and the contour of the designated interval is replaced with a straight line or an arc. According to one or more embodiments of the present invention, the pixel designated by the user is added to the inspection area or excluded from the inspection area in the inspection area correcting step.
[0029] According to one or more embodiments of the present invention, an image inspecting device performs at least any one of the above methods. According to one or more embodiments of the present invention, an inspection area setting device for the image inspecting device performs at least one of the above methods related to the inspection area setting. One or more embodiments of the present invention includes an image inspecting method for performing at least one of the pieces of processing, an inspection area setting method, a program configured to cause the computer to perform the methods, or a recording medium in which the program is recorded.
[0030] According to one or more embodiments of the present invention, the inspection area can simply and accurately be set, even when the object has the complicated or special shape or when the color of the foreground is possibly confused with the color of the background.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a diagram schematically illustrating a configuration of an image inspecting device.
[0032] FIG. 2 is a flowchart illustrating a flow of inspection processing.
[0033] FIG. 3 shows views illustrating an inspection area extracting process in the inspection processing.
[0034] FIG. 4 is a flowchart illustrating a processing flow for setting an inspection area using setting tool 103 .
[0035] FIG. 5 is a view illustrating an example of an inspection area setting screen.
[0036] FIG. 6 shows views exemplifying a process of narrowing down the inspection area by parameter adjustment.
[0037] FIGS. 7( a ) to 7 ( e ) are views illustrating an operation example of a contour correcting tool.
[0038] FIGS. 8( a ) to 8 ( c ) are views illustrating an operation example of a contour drawing tool.
[0039] FIGS. 9( a ) to 9 ( c ) are views illustrating an operation example of an arc converting tool.
[0040] FIGS. 10( a ) to 10 ( c ) are views illustrating an operation example of a line converting tool.
[0041] FIGS. 11( a ) to 11 ( c ) are views illustrating an operation example of a draw tool.
DETAILED DESCRIPTION
[0042] Hereinafter, embodiments of the present invention will be described below with reference to the drawings. In embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention.
[0043] One or more of the following embodiments relate to an image inspecting device that performs an appearance inspection using an image, particularly to an inspection area setting device that aids work to set an inspection area to the image inspecting device. The image inspecting device according to one or more embodiments of the present invention is used to continuously inspect many articles in an automatic or semi-automatic manner on an FA production line. In the image inspecting device of one or more of the embodiments, because the inspection is performed by extracting a predetermined inspection area from an original image taken with an image sensor, it is assumed that a position and a shape of an inspection area are fixed in the original image irrespective of the kind of the article as an inspection object. Although there are various purposes and inspection items for the appearance inspection, the inspection area setting device of one or more of the embodiments can be applied to any inspection. In one or more of the embodiments, the inspection area setting device is mounted in a form of one function (setting tool) of the image inspecting device. Alternatively, the image inspecting device and the inspection area setting device may separately be formed.
First Embodiment
Image Inspecting Device
[0044] FIG. 1 is a diagram schematically illustrating a configuration of an image inspecting device. Image inspecting device 1 is a system that performs the appearance inspection of inspection object 2 conveyed on a conveying path.
[0045] As illustrated in FIG. 1 , image inspecting device 1 includes pieces of hardware such as device body 10 , image sensor 11 , display device 12 , storage device 13 , and input device 14 . Image sensor 11 is a device that captures a color or monochrome still or moving image in device body 10 . For example, according to one or more embodiments of the present invention, a digital camera can be used as image sensor 11 . However, in the case that not a visible-light image but special images (such as an X-ray image and a thermo image) are used, a sensor may be used according to the special image. Display device 12 is one that displays a GUI screen related to the image captured with image sensor 11 , an inspection result, inspection processing, and setting processing. For example, a liquid crystal display can be used as display device 12 . Storage device 13 is one in which various pieces of setting information (such as inspection area-defining information and inspection logic) referred to by image inspecting device 1 during the inspection processing and the inspection result are stored. For example, an HDD, an SSD, a flash memory, and a network storage can be used as storage device 13 . Input device 14 is one that is operated by a user in order to input an instruction to device body 10 . For example, a mouse, a keyboard, a touch panel, and a dedicated console can be used as input device 14 .
[0046] Device body 10 can be constructed with a computer that includes a CPU (Central Processing Unit), a main storage device (RAM), and auxiliary storage device (such as a ROM, the HDD, and the SSD) as hardware. Device body 10 includes inspection processor 101 , inspection area extracting unit 102 , and setting tool 103 as functions. Inspection processor 101 and inspection area extracting unit 102 are the function related to the inspection processing, and setting tool 103 is the function of aiding user work to set setting information necessary for the inspection processing. These functions are implemented in a manner such that a computer program stored in the auxiliary storage device or storage device 13 is loaded on the main storage device and executed by the CPU. FIG. 1 illustrates only an example of a device configuration. Alternatively, all or some of image sensor 11 , display device 12 , storage device 13 , and input device 14 may be integral with device body 10 . Device body 10 may be constructed with a personal computer or a slate computer, or may be constructed with a dedicated chip or an on-board computer.
[0047] (Inspection Processing)
[0048] An operation related to the inspection processing by image inspecting device 1 will be described with reference to FIGS. 2 and 3 . FIG. 2 is a flowchart illustrating a flow of the inspection processing, and FIG. 3 shows views illustrating an inspection area extracting process in the inspection processing. For the sake of convenience, the flow of the inspection processing is described by taking an inspection (detection of a flaw and color unevenness) of a panel surface of a chassis component in a mobile phone as an example.
[0049] In Step S 20 , image sensor 11 takes an image of inspection object 2 , and image data is captured by device body 10 . At this point, the captured image (original image) is displayed on display device 12 as needed basis. An upper stage of FIG. 3 illustrates an example of the original image. The image of chassis component 2 as the inspection object is taken in a center of the original image, and images of adjacent chassis components on the conveying path are partially taken on right and left of the chassis component of the inspection object.
[0050] In Step S 21 , inspection area extracting unit 102 reads necessary setting information from storage device 13 . The setting information includes at least the inspection area-defining information and the inspection logic. The inspection area-defining information is one that defines the position and the shape of the inspection area to be extracted from the original image. The inspection area-defining information has any form. For example, a bit mask in which a label is changed between inside and outside the inspection area and vector data in which a contour of the inspection area is expressed by a Bezier curve or a spline curve can be used as the inspection area-defining information. The inspection logic is information that defines a content of the inspection processing. For example, the kind of the feature quantity used in the inspection, a determination method, and a parameter and a threshold used in feature quantity extraction or determination processing correspond to the inspection logic.
[0051] In Step S 22 , inspection area extracting unit 102 extracts the possible inspection area from the original image according to the inspection area-defining information. A middle stage of FIG. 3 illustrates a state in which inspection area (indicated by cross-hatching) 30 defined by the inspection area-defining information is superimposed on the original image. It is found that inspection area 30 is just superimposed on the panel surface of chassis component 2 . A lower stage of FIG. 3 illustrates a state in which the image (inspection area image 31 ) of inspection area 30 is extracted from the original image. The conveying path and adjacent components seen in the previous images around chassis component 2 are deleted in inspection area image 31 . Hinge portion 20 and button portion 21 , which are excluded from a target region of the surface inspection, are also deleted. Obtained inspection area image 31 is transferred to inspection processor 101 .
[0052] In Step S 23 , inspection processor 101 extracts the necessary feature quantity from inspection area image 31 according to the inspection logic. In the first embodiment, colors of pixels of inspection area image 31 and an average value thereof are extracted as the feature quantity in order to inspect the flaw and the color unevenness of the surface.
[0053] In Step S 24 , inspection processor 101 determines the existence or non-existence of the flaw and the color unevenness according to the inspection logic. For example, in the case that a pixel group in which a color difference from the average value obtained in Step S 23 exceeds a threshold, inspection processor 101 can determine the pixel group to be the flaw or the color unevenness.
[0054] In Step S 25 , inspection processor 101 displays the inspection result on display device 12 , or stores the inspection result in storage device 13 . Therefore, the inspection processing is completed for one inspection object 2 . In the production line, the pieces of processing in Steps S 20 to S 25 of FIG. 2 are repeated in synchronization with the conveyance of inspection object 2 to an angle of view of image sensor 11 .
[0055] In the appearance inspection, desirably only the pixels to be inspected are cut out as inspection area image 31 in just proportion. When a background portion or an excess portion (in the example of FIG. 3 , hinge portion 20 and button portion 21 ) is included in inspection area image 31 , the pixels of the background portion or the excess portion cause a noise to possibly degrade inspection accuracy. On the other hand, when inspection area image 31 is smaller than a range to be inspected, there is a risk of generating omission of the inspection. Therefore, in image inspecting device 1 of the first embodiment, setting tool 103 is prepared in order to simply produce the inspection area-defining information cutting out the accurate inspection area image.
[0056] (Inspection Area Setting Processing)
[0057] The function and the operation of setting tool 103 will be described with reference to FIGS. 4 and 5 . FIG. 4 is a flowchart illustrating a processing flow for setting the inspection area using setting tool 103 , and FIG. 5 is a view illustrating an example of an inspection area setting screen.
[0058] When setting tool 103 is started up, a setting screen in FIG. 5 is displayed on display device 12 . Image window 50 , image capturing button 51 , foreground designating button 52 , background designating button 53 , priority adjusting slider 54 , and confirm button 55 are provided in the setting screen. Manipulations such as selection of a button and movement of a slider can be performed using input device 14 . The setting screen is illustrated only by way of example. Any UI may be used as long as the parameter can be input or the inspection area can be checked as described later.
[0059] When image capturing button 51 is pressed, setting tool 103 takes an image of a sample of the inspection object with image sensor 11 (Step S 40 ). A non-defective inspection object (in the example, the chassis component) is used as the sample, and the image of the sample is taken in the same state (for example, regarding illumination and a relative position between image sensor 11 and sample) as the actual inspection processing. The obtained sample image data is captured in device body 10 . In the case that the previously-taken sample image exists in the auxiliary storage device or storage device 13 of device body 10 , setting tool 103 may read the data of the sample image from the auxiliary storage device or storage device 13 .
[0060] The sample image obtained in Step S 40 is displayed in image window 50 of the setting screen as illustrated in FIG. 5 (Step S 41 ).
[0061] In Step S 42 , the user inputs representative colors (in the case of the monochrome image, representative brightness) of a foreground and a background. The foreground indicates a portion that should be extracted as the inspection area, and the background indicates a portion except the inspection area. In the case that the user inputs the representative color of the foreground, the user presses foreground designating button 52 to change the setting screen to a foreground designating mode, and designates a portion that should be set to the foreground on the sample image displayed in image window 50 . At this point, because the designation is made to pick up the representative color of the foreground, some pixels or a pixel group on the panel surface of the chassis component may properly be selected in the example of FIG. 5 . When a largely different pattern, shade and shadow, or color portion is included in the foreground, according to one or more embodiments of the present invention, the pixel group is selected such that related colors are covered as much as possible. In the case that the user inputs the representative color of the background, the user presses background designating button 53 to change the setting screen to a background designating mode, and performs the similar manipulation. It is not always necessary to input the representative colors of the foreground and the background. Only one of the foreground and the background may be input, or Step S 42 may be eliminated in the case that the representative color is already known or in the case that the representative color can automatically be calculated from a color distribution of the sample image.
[0062] In Step S 43 , based on the representative colors of the foreground and the background that are designated in Step S 42 , setting tool 103 separates (segments) the sample image into the foreground and the background and selects the foreground portion as the inspection area. In the first embodiment, using information on an edge included in the sample image in addition to information on the color of each pixel of the sample image, both a degree of color separation (hereinafter referred to as pixel separation) between the foreground and the background (that is, between the inside and the outside of the candidate area) and a degree of overlap (hereinafter referred to as edge overlap) between a boundary of the foreground and the background (that is, the contour of the candidate area) and the edge in the sample image are comprehensively evaluated with respect to the plurality of candidate areas that are of candidate solutions of the inspection area, and an optimal solution is searched such that both the pixel separation and the edge overlap are enhanced. A method for calculating the inspection area is described later in detail.
[0063] In Step S 44 , the inspection area calculated in Step S 43 is displayed on image window 50 of the setting screen. The user can check whether the desired area is selected as the inspection area by seeing the inspection area displayed on the setting screen. At this point, when the inspection area is overlaid on the sample image, according to one or more embodiments of the present invention, the inspection object and the inspection area are easily compared to each other.
[0064] Then setting tool 103 waits for the input from the user (Step S 45 ). In the case that confirm button 55 is pressed, setting tool 103 generates inspection area-defining information on the current inspection area and stores the inspection area-defining information in storage device 13 (Step S 46 ). On the other hand, in the case that the improper inspection area is displayed on the setting screen, the user can adjust the parameter by manipulating foreground designating button 52 , background designating button 53 , and priority adjusting slider 54 (Step S 47 ). Re-designation of the representative color of the foreground or the background has an influence on the evaluation of the pixel separation. When a priority between the color information and the edge information is changed using priority adjusting slider 54 , a balance (weight) can be changed in evaluating the pixel separation and the edge overlap. When receiving the input (change) of the parameter from the user, setting tool 103 recalculates the optimal solution of the inspection area with the new parameter as a constraint condition, and displays the post-recalculation inspection area on the setting screen (Step S 47 →Steps S 43 and S 44 ). Therefore, while the parameter is properly adjusted, the calculation of the inspection area can be repeated until the desired result is obtained.
[0065] FIG. 6 shows views exemplifying a process of narrowing down the inspection area by parameter adjustment. An upper stage of FIG. 6 illustrates inspection area 30 obtained by the initial calculation. In the initial calculation result, hinge portion 20 and button portion 21 of the chassis component are also included in inspection area 30 . However, hinge portion 20 and button portion 21 are desired to be excluded from the inspection area because the inspection for the flaw and the color unevenness inspection is directed to the panel surface (see FIG. 3 ). Therefore, the user first presses background designating button 53 to change the setting screen to the background designating mode, and additionally designates the color of button portion 21 in the sample image to the representative color of the background. Therefore, button portion 21 is excluded from inspection area 30 as illustrated in the image example of the middle stage in FIG. 6 . Then, hinge portion 20 is dealt with by adjusting a balance parameter because hinge portion 20 has a little color difference with the panel surface. That is, by focusing on the edge in a step between hinge portion 20 and the panel surface, the priority of the edge information is enhanced using priority adjusting slider 54 . Therefore, as illustrated in the image example of the lower stage in FIG. 6 , the contour of inspection area 30 is set to the edge between hinge portion 20 and the component surface to form desired inspection area 30 .
[0066] (Calculation of Inspection Area)
[0067] The inspection area calculating method in Step S 43 of FIG. 4 will be described below.
[0068] As described above, in setting tool 103 of the first embodiment, the optimal solution is obtained from the candidate solutions of the inspection area by comprehensively evaluating both the pixel separation between the foreground and the background and the edge overlap of the boundary of the foreground and the background. The calculation can be considered as an optimization problem that minimizes (or maximizes) an objective function including a function evaluating the pixel separation based on the color information and a function evaluating the edge overlap based on the edge information. A technique of solving the optimization problem of the inspection area using a graph cut algorithm will be described below. Because the graph cut algorithm is a well-known technique (see Non-Patent Document 1), the description of a basic concept of the graph cut algorithm is neglected, and a portion unique to the first embodiment is mainly described.
[0069] In the graph cut algorithm, as indicated by the following equation, an energy function is defined as the objective function, and solution L minimizing energy E is obtained when I is provided. In the first embodiment, I is the sample image, and L is a label (that is, the inspection area) indicating the foreground or the background.
[0000]
[
Mathematical
formula
1
]
E
(
L
I
)
=
∑
i
∈
Ω
U
(
l
i
I
)
+
λ
∑
{
i
,
j
}
∈
N
V
(
l
i
,
l
j
I
)
(
1
)
[0000] Where i and j are indexes of the pixel, Ω is a pixel group in the image I, and N is an adjacent pixel pair group in the image I. li and lj are designated labels of the pixels i and j. It is assumed that a label of “1” is provided for the foreground, and that a label of “0” is provided for the background. A first term of the right side is called a data term, and provides the constraint condition related to a target pixel i. A second term of the right side is called a smoothing term, and provides the constraint condition related to the pixels i and j adjacent to each other. λ is a balance parameter deciding the weights of (balance between) the data term and the smoothing term.
[0070] The data term is defined by the function evaluating the pixel separation based on the color information. For example, an evaluation function U of the data term may be defined by the following equation.
[0000]
[
Mathematical
formula
2
]
U
(
l
i
I
)
=
{
-
log
p
(
I
l
i
=
1
)
,
if
l
i
=
1
-
log
p
(
I
l
i
=
0
)
,
if
l
i
=
0
(
2
)
[0071] Where −log p(I|li=1) is a function (logarithmic likelihood) expressing a likelihood of the foreground of a foreground pixel (a pixel on which the foreground label of “1” is put) with respect to the foreground representative color, and is called a foreground likelihood. A function estimated from the foreground representative color (for example, the color distribution of the foreground representative color is approximated by a Gaussian mixture model) is used as a probability density function in the foreground likelihood. On the other hand, −log p(I|li=0) is a function (logarithmic likelihood) expressing a likelihood of the background of a background pixel (a pixel on which the background label of “0” is put) with respect to the background representative color, and is called a background likelihood. A function estimated from the background representative color (for example, the color distribution of the background representative color is approximated by the Gaussian mixture model) is used as a probability density function in the background likelihood. That is, the data term expresses a summation of the foreground likelihoods of the foreground pixels and the background likelihoods of the background pixels, the energy decreases as the color of the foreground pixel comes closer to the foreground representative color and as the color of the background pixel comes closer to the background representative color, and the energy increases as the color of the foreground pixel is further separated from the foreground representative color and as the color of the background pixel is further separated from the background representative color.
[0072] The smoothing term is defined by a function evaluating the edge overlap based on the edge information. For example, an evaluation function V of the smoothing term can be defined by the following equation.
[0000]
V
(
l
i
,
l
j
I
)
=
{
exp
{
-
β
I
i
-
I
j
2
}
,
if
l
i
≠
l
j
0
,
if
l
i
=
l
j
[
Mathematical
formula
3
]
[0073] Where li and lj are pixel values (color or brightness) of the pixels i and j and β is a coefficient. ∥li−lj∥ 2 expresses a difference (distance) between the pixel values on a predetermined color space, namely, a height of contrast between the pixels.
[0074] According to the above equation, in the case that the adjacent pixels i and j differ from each other in the label, the energy increases with decreasing contrast between the pixels i and j, and the energy decreases with increasing contrast. The portion having the high contrast between the adjacent pixels is one in which the color or the brightness changes largely in the image, namely, the edge portion in the image. That is, in the equation, the energy decreases as larger portions of the boundary (pixel pair having different labels) of the foreground and the background overlaps the edge in the image.
[0075] A global minimum exists in the above energy function when submodularity is satisfied. Similarly, when a term satisfying the submodularity is added, the global minimum can be obtained with the constraint condition. Because a well-known search algorithm may be used to efficiently solve the global minimum, the detailed description is neglected.
[0076] In the parameters that can be adjusted on the setting screen, “the foreground representative color” and “the background representative color” have an influence on the value of the data term. “The priority between the color information and the edge information” corresponds to the balance parameter λ. When the user enhances the priority of the color information, the weight of the data term is increased by decreasing the value of the parameter λ. When the user enhances the priority of the edge information, the weight of the smoothing term is increased by increasing the value of the parameter λ. The value of the parameter λ can also automatically be decided by a computing machine (setting tool 103 ). For example, setting tool 103 calculates the difference between the foreground representative color and the background representative color, and the weight of the data term is increased by decreasing the value of the parameter λ in the case of the large difference. This is because the data term has high reliability in the case of the clear color difference between the foreground and the background. On the other hand, the weight of the smoothing term is increased by increasing the value of the parameter λ in the case of the small difference between the foreground representative color and the background representative color. This is because area segmentation based on the edge information tends to provide a good result rather than based on the color information in the case of the unclear color difference between the foreground and the background. Thus, the potential to reach an adequate solution can be enhanced in the absence of user aid by automatically adjusting the balance parameter λ. According to one or more embodiments of the present invention, the initial value of the balance parameter λ is automatically decided by the above method, and the user may adjust the balance parameter λ, (the priority between the color information and the edge information) with the initial value as a starting point. This is because, with increasing adequacy of the initial value, the number of trial-and-error times of the user can be decreased and a workload on the parameter adjustment can be expected to be reduced.
[0077] In the equation (2), the summation of the likelihoods of the foregrounds of the foreground pixel (foreground likelihood) and the likelihoods of the backgrounds of the background pixel (background likelihood) is used as the data term. However, the evaluation function of the pixel separation is not limited to the summation. For example, a product of the foreground likelihood and the background likelihood, a weighted sum, a weighted product, a non-linear function sum, and a non-linear function product may be used as the data term. A monotonically increasing function may be used as the non-linear function. A function in which both the foreground likelihood and the background likelihood are not evaluated but only one of the foreground likelihood and the background likelihood is evaluated can be used as the pixel separation. Specifically, a function in which U(li|I) becomes zero for li=0 (or li=1) can be used in the equation (2). The following equation (4) is a function evaluating only the foreground likelihood.
[0000]
U
(
l
i
I
)
=
{
-
log
p
(
I
l
i
=
1
)
,
if
l
i
=
1
0
,
if
l
i
=
0
[
Mathematical
formula
4
]
[0078] Either all the foreground pixels (that is, all the pixels inside the candidate area) or only some foreground pixels may be used to calculate the foreground likelihood. Similarly, either all the background pixels (that is, all the pixels outside the candidate area) or only some background pixels may be used to calculate the background likelihood. For example, a calculation time can be shortened by excluding the pixel in which the label is fixed from the calculation or by using only the pixel existing within a predetermined distance from the contour of the candidate area.
[0079] The function evaluating the foreground likelihood or the background likelihood is not limited to the equation (2). For example, a likelihood ratio that is of a ratio of the foreground likelihood to the background likelihood can be used as expressed by the following equation.
[0000]
U
(
l
i
I
)
=
{
-
log
p
(
I
l
i
=
1
)
p
(
I
l
i
=
0
)
,
if
l
i
=
1
-
log
p
(
I
l
i
=
0
)
p
(
I
l
i
=
1
)
,
if
l
i
=
0
[
Mathematical
formula
5
]
[0080] Using directly a histogram of the pixel group that is designated as the foreground representative color by the user (without estimating the probability density function), the foreground likelihood may be evaluated based on a similarity of color of each pixel with respect to the histogram of the foreground representative color, or the background likelihood may be evaluated based on a dissimilarity of color of each pixel with respect to the histogram of the foreground representative color. Similarly, the background likelihood may be evaluated based on a similarity with respect to a histogram (a histogram of the background representative color) of the pixel group that is designated as the background representative color by the user, or the foreground likelihood may be evaluated based on a dissimilarity with respect to the histogram of the background representative color. Alternatively, the similarity or the dissimilarity between a foreground histogram obtained from the foreground pixel group or a background histogram obtained from the background pixel group of the candidate area and the histogram of the foreground representative color or the histogram of the background representative color may be calculated using a predetermined function or a distance index. Alternatively, a histogram may be approximated from the information on the color or the brightness of the pixel group to calculate the similarity or the dissimilarity using the approximated histogram.
[0081] (Additional Parameter)
[0082] The three parameters of the foreground representative color, the background representative color, and the priority between the color information and the edge information are described above in the first embodiment. Additionally, any parameter may be used as long as the parameter can have an influence on the optimal solution search of the inspection area. For example, frequently the shape, the texture, the topology of the inspection area, the element adjacent to the inspection area, and the element included in the inspection area have the feature because the appearance inspection is mainly aimed at industrial products. The image sensor is installed such that the inspection object is fitted into the angle of view, so that the size of the inspection area or the position in the image of the inspection area can be predicted to some extent. Therefore, by inputting the information expressing the feature of the inspection area as the parameter by the user, and adding the constraint condition that evaluates the similarity between the feature provided by the parameter and the feature of the inspection area to the objective function, the potential to search the adequate inspection area is further enhanced.
[0083] A basic shape (such as a circle, a quadrangle, a triangle, and a star) of the inspection area and the feature (such as a linear outer shape, a round outer shape, and a jagged shape) of the contour can be used as shape information expressing the feature related to the shape of the inspection area. As to a UI used to input the shape information, template of the basic shapes or the features of the contours are listed, and the user may select the corresponding item. For example, in the case that the template of the basic shape is designated, the following expression may be inserted as the constraint condition.
[0000]
min
log
∑
i
l
i
-
T
(
t
i
)
2
[
Mathematical
formula
6
]
[0084] Where li is a designated label of the pixel i and ti is a label of a point corresponding to the pixel i on the template. T( ) expresses an affine transform. The above expression expresses a manipulation in which template matching is performed to the candidate area while the designated template is enlarged/reduced, rotated, and deformed and thereby calculating the minimum score. That is, the energy of the area having the shape closer to the basic shape designated by the user is decreased by the addition of the constraint condition, and the area is preferentially selected as the optimal solution.
[0085] For example, in the case that jaggedness or smoothness is designated as the feature of the contour, the following expression may be inserted as the constraint condition.
[0000]
log
{
∑
∂
θ
∂
S
-
C
2
}
[
Mathematical
formula
7
]
[0086] Where S is a point on the contour of the foreground area, θ is a gradient angle of the contour, and ∂θ/∂S expresses an amount of change of the gradient angle along the contour of the foreground area. C is a constant indicating the jaggedness (smoothness) designated by the user, and the value C increases with increasing jaggedness while the value C decreases with increasing smoothness. The above expression is a function evaluating whether a total value (expressing the jaggedness of the contour) of the amounts of change in the gradient angle along the contour of the foreground area is close to the value C (expressing the jaggedness designated by the user). That is, the area having the contour feature closer to the jaggedness designated by the user is preferentially selected as the optimal solution by the addition of the constraint condition.
[0087] An area, a vertical length, and a horizontal length of the inspection area can be used as size information expressing the feature related to the size of the inspection area. For example, in the case that the area is input as the size information, the following expression may be inserted as the constraint condition.
[0000]
log
{
∑
i
l
i
-
C
2
}
[
Mathematical
formula
8
]
[0088] Where C is the area (the number of pixels) of the foreground area designated by the user. Because of the foreground label of 1 and the background label of 0, Σli expresses the total number of the foreground pixels, namely, the area of the foreground area. Accordingly, the above expression is a function evaluating whether the area of the foreground area is close to the area C designated by the user. The area having the size closer to the area designated by the user is preferentially selected as the optimal solution by the addition of the constraint condition.
[0089] Centroid coordinates of the inspection area and an existence range (such as up, down, right, left, and center) of the inspection area can be used as position information expressing the feature related to the position in the image of the inspection area. For example, in the case that the centroid coordinates are input as the position information, the following expression may be inserted as the constraint condition.
[0000] log {∥ w−C∥ 2 } [Mathematical formula 9]
[0090] Where w is centroid coordinates of the foreground area and C is centroid coordinates designated by the user. The above expression is a function evaluating whether the centroid coordinates of the foreground area are close to the coordinates C designated by the user. The area having the centroid at the position closer to the coordinates designated by the user is preferentially selected as the optimal solution by the addition of the constraint condition.
[0091] Information expressing a pattern, shading of the color, irregularity, or a material in the inspection area can be used as texture information expressing the feature related to the texture of the inspection area. For example, various texture templates are listed, and the user may select a corresponding texture template from the list. For example, in the case that the texture template is input, the following expression may be input as the constraint condition.
[0000] log f ( h l=1 ( I )− h l=1 ( E )) [Mathematical formula 10]
[0092] Where I is a sample image and E is a texture template designated by the user. A color histogram of the foreground pixel is expressed by h l=1 ( ) and a function indicating a similarity between the histograms is expressed by f( ). That is, the above expression is a function evaluating whether the color histogram of the foreground area in the sample image is similar to the color histogram of the texture designated by the user. The area having the texture similar to the texture designated by the user is preferentially selected as the optimal solution by the addition of the constraint condition.
Advantage of First Embodiment
[0093] According to setting tool 103 of the first embodiment, the position and the shape of the inspection area are decided by the optimal solution search in which the sample image is used. Therefore, compared with the conventional technique of manually inputting the inspection area using the simple graphics, the setting time and the workload can significantly be reduced, and the complicated shape and the special shape can be dealt with. Both the pixel separation of the color or the brightness between the inside and the outside of the inspection area and the edge overlap of the contour of the inspection area and the edge are comprehensively evaluated using the information on the edge in addition to the information on the color or the brightness, which allows the area extraction accuracy to be improved compared with the conventional technique such as the binarization and the color gamut extraction.
[0094] In setting tool 103 of the first embodiment, the user can arbitrarily select the priority between the color information and the edge information on the setting screen. For example, according to one or more embodiments of the present invention, the higher priority is put on the information on the color or the brightness rather than the information on the edge in the case that the image includes many pseudo-contours as in a case that a pattern is included in the foreground or the background. Whereas, according to one or more embodiments of the present invention, the higher priority is put on the information on the edge in the case of the image in which the color of the foreground is similar to the color of the background. For the image in which the foreground and the background are hardly separated from each other, it is very difficult to find the answer by the completely automatic method. At the same time, when seeing the image, the user can easily determine which one of the information on the color or the brightness and the information on the edge should have the higher priority, and the user can narrow down the parameter by trial and error. Accordingly, the balance parameter can be adjusted, whereby the desired inspection area can simply be set in a short time.
Second Embodiment
[0095] A second embodiment of the present invention will be described below. In the setting tool of the first embodiment, the inspection area can be narrowed down by adjusting the parameters such as the foreground and background representative colors and the priority between the color and the edge. However, only the adjustment of the parameter generates a risk that the user cannot reach the shape of the inspection area intended (some errors are left), and possibly it takes a long time to perform the trial and error of the parameter only by the adjustment of the parameter. Therefore, an inspection area correcting function that the user can interactively correct the shape of the inspection area after the inspection area is obtained by the calculation is provided in a setting tool of the second embodiment.
[0096] Hereinafter, (1) a contour correcting tool, (2) a contour drawing tool, (3) an arc converting tool, (4) a line converting tool, and (5) a draw tool will be described as examples of the inspection area correcting function provided by the setting tool of the second embodiment. For example, these tools can be started up from the setting screen in FIG. 5 . The configuration of the image inspecting device, the operation of the inspection processing, and the operation of the automatic calculation (optimization) of the inspection area are similar to those of the first embodiment, the description is neglected.
[0097] (1) Contour Correcting Tool
[0098] FIGS. 7( a ) to 7 ( e ) are views illustrating an operation example of a contour correcting tool. FIG. 7( a ) illustrates an image of inspection object (sample) 70 , and FIG. 7( b ) illustrates an automatic calculation result of inspection area 71 . It is assumed that a gap is generated between the contours of inspection object 70 and inspection area 71 as illustrated in FIG. 7( b ).
[0099] When the user starts up the contour correcting tool, the contour correcting tool approximates the contour of inspection area 71 using path 72 of a Bezier curve or a spline curve, and displays path 72 on the screen together with control points 73 as illustrated in FIG. 7( c ). At this point, path 72 and control points 73 are overlaid on the image of inspection object 70 . The user performs the correction, the addition, and the deletion of control point 73 using input device 14 , which allows the shape of path 72 to be freely corrected. The result corrected by the user is instantaneously reflected in the screen display. Accordingly, the user can easily adjust the shape of path 72 to the contour of inspection area 71 while checking the shape of path 72 on the screen. FIG. 7( d ) illustrates post-correction path 72 .
[0100] When the user issues an instruction to confirm the path after the correction of path 72 is completed by the manipulation, the contour correcting tool converts the area surrounded by path 72 into inspection area 71 . Therefore, inspection area 71 having the shape intended by the user is obtained.
[0101] (2) Contour Drawing Tool
[0102] FIGS. 8( a ) to 8 ( c ) are views illustrating an operation example of a contour drawing tool. FIG. 8( a ) is a partially enlarged view illustrating the image of inspection object 70 and automatically-calculated inspection area 71 . It is assumed that a gap is generated between the contours of inspection object 70 and inspection area 71 as illustrated in FIG. 8( a ).
[0103] When the user starts up the contour drawing tool, the display screen is changed to a contour drawing mode, and free curve 74 can be drawn on the image using input device 14 . For example, in the case that a mouse is used as input device 14 , a locus of a moving mouse cursor is drawn as free curve 74 from when a button of the mouse is pressed until when the button is released. When the user does not successfully draw free curve 74 , the contour drawing mode may be canceled to restart the manipulation from the beginning.
[0104] When the user issues the instruction to confirm the contour after the drawing of free curve 74 is completed by the manipulation, the contour drawing tool synthesizes free curve 74 and inspection area 71 such that free curve 74 constitutes a part of the contour of inspection area 71 . FIG. 8( c ) illustrates post-synthesis inspection area 71 . Any technique may be used to synthesize free curve 74 and inspection area 71 . For example, smoothing may be performed to smooth a connection portion of free curve 74 and the contour of inspection area 71 , or the shape of free curve 74 . In the case that an end point of free curve 74 is away from the contour of inspection area 71 , free curve 74 and the contour of inspection area 71 may be connected to each other at a nearest neighbor point, or interpolation may be performed such that free curve 74 and the contour of inspection area 71 are smoothly connected to each other. Inspection area 71 having the shape intended by the user is obtained by the above manipulation.
[0105] (3) Arc Converting Tool
[0106] FIGS. 9( a ) to 9 ( c ) are views illustrating an operation example of an arc converting tool. FIG. 9( a ) is a partially enlarged view illustrating the image of inspection object 70 and automatically-calculated inspection area 71 . It is assumed that a gap is generated between the contours of inspection object 70 and inspection area 71 as illustrated in FIG. 9( a ).
[0107] When the user starts up the arc converting tool, the screen display is changed to an arc input mode, and an arc can be input on the image using input device 14 . For example, in the case that the mouse is used as input device 14 , the mouse cursor is moved and clicked at three points, namely, two points (1 and 2) on the contour of inspection area 71 and a passing point (3) of the arc as illustrated in FIG. 9( b ). Therefore, the arc passing through the point 3 with the points 1 and 2 as the starting and ending points is calculated and overlaid on the image. In the case that the shape of the arc differs from an intended shape, position of each point may be corrected, or the arc input mode may be canceled to restart the manipulation from the beginning. In the second embodiment, the arc is designated by the three points of the arc, namely, the starting point, the ending point, and the passing point. Alternatively, the arc may be input by another designation method.
[0108] When the user issues the instruction to confirm the arc after the designation of the arc is completed by the manipulation, the arc converting tool substitutes the contour in an interval between the starting point (1) and the ending point (2) in the contour of inspection area 71 for the arc. At this point, in the case that the starting point (1) or the ending point (2) is away from the contour of inspection area 71 , the arc and the contour of inspection area 71 may be connected to each other at the nearest neighbor point, or the interpolation may be performed such that the arc and the contour of inspection area 71 are smoothly connected to each other. The contour in the partial interval of inspection area 71 can easily be shaped into the arc by the above manipulation.
[0109] (4) Line Converting Tool
[0110] FIGS. 10( a ) to 10 ( c ) are views illustrating an operation example of a line converting tool. FIG. 10( a ) is a partially enlarged view illustrating the image of inspection object 70 and automatically-calculated inspection area 71 . It is assumed that a gap is generated between the contours of inspection object 70 and inspection area 71 as illustrated in FIG. 10( a ).
[0111] When the user starts up the line converting tool, the screen display is changed to a line input mode, and a line segment can be input on the image using input device 14 . For example, in the case that the mouse is used as input device 14 , the mouse cursor is moved and clicked at two points ( 1 and 2 ) on the contour of inspection area 71 as illustrated in FIG. 10( b ). Therefore, the line segment in which the points 1 and 2 are set to the starting and ending points is calculated and overlaid on the image. In the case that the shape of the line segment differs from an intended shape, position of each point may be corrected, or the line input mode may be canceled to restart the manipulation from the beginning. In the second embodiment, the line is designated by the two points, namely, the starting point, and the ending point. Alternatively, the line may be input by another designation method.
[0112] When the user issues the instruction to confirm the line after the designation of the line is completed by the manipulation, the line converting tool substitutes the contour in the interval between the starting point (1) and the ending point (2) in the contour of inspection area 71 for the line segment. At this point, in the case that the starting point (1) or the ending point (2) is away from the contour of inspection area 71 , the line segment and the contour of inspection area 71 may be connected to each other at the nearest neighbor point, or the interpolation may be performed such that the line segment and the contour of inspection area 71 are smoothly connected to each other. The contour in the partial interval of inspection area 71 can easily be shaped into the line by the above manipulation.
[0113] (5) Draw Tool
[0114] FIGS. 11( a ) to 11 ( c ) are views illustrating an operation example of a draw tool. FIG. 11( a ) is a partially enlarged view illustrating the image of inspection object 70 and automatically-calculated inspection area 71 . In the draw tool, because inspection area 71 is corrected in units of pixels, a grid of pixels is illustrated in FIGS. 11( a ) to 11 ( c ) for the sake of convenience. It is assumed that a gap is generated between the contours of inspection object 70 and inspection area 71 as illustrated in FIG. 11( a ), that inspection area 71 is smaller than inspection object 70 in the upper portion of FIG. 11( a ), and that inspection area 71 is larger than inspection object 70 in the right of FIG. 11( a ).
[0115] When the user starts up the draw tool, the screen display is changed to a draw mode, and a pixel to be added to inspection area 71 can be designated on the image using input device 14 or a pixel to be deleted from inspection area 71 can be designated on the image using input device 14 . FIG. 11( b ) illustrates a state in which pixels are added to the inspection area. For example, in the case that the mouse is used as input device 14 , pixels to be added are sequentially selected or the mouse cursor is moved while a predetermined button is pressed, whereby area (pixel group) 75 to be added to inspection area 71 can be designated. On the other hand, FIG. 11( c ) illustrates a state in which pixels are deleted from the inspection area. Area (pixel group) 76 to be deleted from inspection area 71 can be designated similarly to the addition. Inspection area 71 having a shape intended by the user is obtained by the above manipulation.
[0116] According to the configuration of the second embodiment provided with the function of correcting the shape of the inspection area, a portion hardly automatically extracted by the computing machine can be complemented by the user aid, and therefore an optimal inspection area (that is, the inspection area having the user's desired shape) can simply be obtained in a short time. Although the correcting functions (1) to (5) are described in the second embodiment, the setting tool does not necessarily include all the correcting functions. At least one of the functions may be provided, and according to one or more embodiments of the present invention, the setting tool includes another correcting function. According to one or more embodiments of the present invention, during the correcting work, the user can enlarge/reduce the work screen in FIGS. 7( a ) to 11 ( c ) to proceed efficiently with the work or to easily perform a precise input.
[0117] The above embodiments of the present invention are illustrated only by way of example, but the scope of the invention is not limited to the embodiments. For example, although the color information on the image is used in one or more of the embodiments because the color image is considered as the sample image, in the case that a monochrome image is used, brightness information may be used instead of the color information. In addition, although the graph cut algorithm is used in the optimization in one or more of the embodiments, other methods such as a level set algorithm may be used. For other methods, the inspection area can accurately be calculated using the color information (brightness information) and the edge information. In this case, according to one or more embodiments of the present invention, the user can also change the priority between the color information (brightness information) and the edge information.
[0118] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
DESCRIPTION OF SYMBOLS
[0000]
1 image inspecting device
2 inspection object (chassis component)
10 device body
11 image sensor
12 display device
13 storage device
14 input device
101 inspection processor
102 inspection area extracting unit
103 setting tool
20 hinge portion
21 button portion
30 inspection area
31 inspection area image
50 image window
51 image capturing button
52 foreground designating button
53 background designating button
54 priority adjusting slider
55 confirm button
70 inspection object
71 inspection area
72 path
73 control point
74 free curve
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An inspection area setting method for setting inspection area-defining information defining an inspection area to an image inspecting device, the image inspecting device being configured to extract a portion constituting the inspection area as an inspection area image from an original image obtained by taking an image of an inspection object, and to inspect the inspection object by analyzing the inspection area image, includes an acquisition step of acquiring a sample image obtained by taking an image of a sample of the inspection object, an inspection area searching step, and a setting step.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a haymaking machine including a frame with at least one raking wheel equipped with tool-carrying arms directed outward, wherein the raking wheel is guided in rotation on an approximately vertical support pin equipped with at least one support which moves over the ground during work and with a cam which controls the tool-carrying arms so that during their rotation around the support pin, the arms pivot around their respective longitudinal axes, thereby raising the work tools in a certain zone of their path, to deposit the raked products in the form of a windrow.
2. Discussion of the Background
On the type of machine above-described, the support pin of the raking wheel and the control cam are locked in relation to the frame during work. The tool-carrying arms are then controlled by the cam so that they raise their tools constantly in the same zone with respect to the frame of the machine. This type of machine makes it possible to constitute well-formed windrows when it is moved in a straight line. However, in curves or turns, the windrows formed are irregular and very often scattered. Picking up of the products with a pick-up tool such as a baler or a silage harvester is then difficult to perform.
On another type of machine, the control cam which is locked during work can nevertheless be brought into two different positions. To do this, the cam can be released and turned by an angle of about 180° before immobilizing it in the new position. The zone for depositing products can thus be located on the right side or the left side of the machine. This adjustment makes it possible to increase the possibilities of use of the same machine. The latter can actually be drawn or pushed by the tractor. The user can thus select the mode of work as a function of the nature of the products and of the fields over which he works.
However, the adjustment also does not make it possible for the machine to produce well-formed and regular windrows during movements both in straight lines and curves or turns. In addition, the adjustment of the control cam is a time loss factor especially if it must be repeated often.
SUMMARY OF THE INVENTION
Accordingly, one object of this invention is to provide a novel haymaking machine used particularly for windrowing, which does not have the drawbacks of known machines.
A related object of this invention is to provide a new and improved haymaking machine which produces well-formed and regular windrows during movements in straight lines and around curves or turns.
These and other objects are achieved according to the present invention by providing a new and improved haymaking machine in which the support pin which carries the control cam is mounted free in rotation in the frame and is connected by a connecting means to a support which is offset in relation to the support pin in the direction of advance of the machine, wherein the support is stationary with respect to the connecting means in the horizontal plane during work.
In the machine according to the present invention, the support constantly replaces itself behind the support pin and orientates automatically in the direction of movement of the machine during work. Consequently, the support also orients the control cam by the support pin of the raking wheel. The cam is then constantly positioned so that the picking up of the products laid on the ground is performed on the front half--seen in the direction of movement--of the path of the working tools, and so that the depositing of these products takes place in the vicinity of a plane perpendicular to the direction of movement and passing through the support pin of the raking wheel. This positioning of the control cam makes it possible to obtain well-formed windrows during movements in straight lines, curves and turns.
The support solid with the support pin of the raking wheel also provides automatically a pivoting of about 180° of the control cam in the case where the machine is used both as a drawn machine and as a pushed machine. In this way, there is no loss of time to go from one of these work modes to the other, which is particularly advantageous when the machine is moved alternately in forward and in reverse, to avoid turning around at the end of the field.
Another characteristic of the invention is that at least one of the supports of the raking wheel is placed so that during work it exerts a torque on the support pin with the control cam which is approximately equal and opposite the torque exerted by the rollers of the tool-carrying arms on the control cam. This characteristic makes it possible to improve the guiding provided by the support which moves over the ground. According to a very advantageous embodiment, the support which controls the position of the support pin and of the control cam is, in addition, offset laterally in relation to a vertical plane directed in the direction of movement and passing through the support pin. The support is located on the side toward which the tool-carrying arms move when they pass through the plane in the back half of their path.
Thanks to this lateral offsetting, during work there is created a torque opposite the torque exerted on the control cam and the support pin by the rollers of the tool-carrying arms. The value of the lateral offsetting is selected so as to obtain balance between the moments of the two torques. This balance facilitates the guiding provided by the support on the ground. The torque exerted by the rollers of the tool-carrying arms on the control cam no longer influences this guiding. In this way, the support moves the support pin and the cam as easily against the direction of rotation of the tool-carrying arms as in this direction.
Moreover, the guiding is also less dependent on the surface of the ground. Thanks to the balance between the torques, the rollers of the tool-carrying arms do not cause an untimely movement of the control cam as soon as the pressure of the support on the ground decreases a short instant. Thus, the positioning of the control cam is correctly assured even in fields having irregular surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG. 1 is a top view of the haymaking machine according to one embodiment of the present invention;
FIG. 2 is, on a larger scale, a simplified cross-sectional view of the raking wheel of FIG. 1;
FIG. 3 is a top view of a machine according to the invention moved in the reverse direction of the direction of movement of the machine according to FIG. 1;
FIG. 4 is a top view of another embodiment of the machine to the present invention; and
FIG. 5 is, on a larger scale, a cross-sectional view of the raking wheel of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof, the machine according to the invention includes a frame (1) formed particularly of two approximately horizontal beams (2, 3). The front ends of these beams (2, 3) are connected to a three-point hitching bracket (4) that can be coupled to the lifting device (5) of drive tractor (6) which is simply sketched in this FIG. 1.
The two other ends of the beams (2, 3) are connected to a raking wheel (7) equipped with tool-carrying arms (8).
It is particularly clear from FIG. 2 that this raking wheel (7) includes a central casing (9) or the like. This casing (9) includes at its periphery bearings (10) in which tool-carrying arms (8) directed outward are housed. Each of these arms (8) carries at its outside end tools (11) consisting of raking teeth. The inside end of each arm (8) comes out in casing (9) and includes a crank (12) equipped with a roller (13).
This casing (9) includes at its upper part a ring gear (14) which meshes with a pinion (15) solid with a drive shaft (16). Further, casing (9) is guided in rotation on an approximately vertical support pin (17) by means of ball bearings (18, 19). Above casing (9) a stationary cover (20) is provided that is solid with beams (2, 3) of frame (1). This cover (20) protects the ring gear (14) and pinion (15). It includes a housing (21) in which support pin (17) is guided so that it is free in rotation around its geometric axis (34). For this purpose, it can be housed there with a slight radial play. One or more guide elements such as rings, can optionally be provided in the housing (21) to guide the support pin (17).
Support pin (17) carries on its upper part, located in casing (9), a control cam (22) for tool-carrying arms (8). This cam (22) is fastened to support pin (17) by a key (23). Cam 22 includes a cam surface in the form of a guide path (24) in which rollers (13) of tool-carrying arms (8) move. This guide path (24) is approximately circular and includes a low portion (25) and a higher portion (26).
The support pin (17)is locked in translation in relation to frame (1). This is obtained by a shoulder (27) which strikes against a lower face of control cam (22) and, by a stop bushing (28) fastened at the upper end of the support pin (17) by a pin (29). The lower end of support pin (17) is connected with a connecting arm (30) to at least one support (31) which rests on the ground. This support (31) is offset backwards in relation to pin (17)--seen in the direction of advance A--and is stationary in relation to connecting means (30) in the horizontal plane. In the example shown, support (31) consists of a small wheel which rolls over the ground during work. This small wheel (31) is attached to connecting arm (30) by a column (32). This connecting arm is itself fastened, for example, with bolts to a plate (33) solid with support pin (17).
It is clear from the above-described arrangement that support pin (17), control cam (22) and support (31) are connected rigidly to one another and form an assembly that can pivot around the longitudinal geometric axis (34) of the support pin (17).
Two additional supports (35 and 36) are further connected to support pin (17) to increase the stability of the machine and to improve the adaptation to the irregularities of the ground. In relation to this pin (17), these two support (35, 36) are located on the side opposite the one on which the support (31) is located (see FIG. 2). Supports (35, 36) are parallel to one another and are located at a certain distance from one another. Their connection to support pin (17) is provided by the arm (30) which passes under the pin (17) and which carries at its end a crosswise arm (37) to which the supports (35, 36) are connected so as to be able to pivot in a horizontal plane. For this purpose, the crosswise arm (37) includes near each of its ends an approximately vertical pivot pin (38 and 39) to which corresponding support (35 or 36) is connected by a column (40, 41) that is inclined toward the back. These two additional supports (35, 36) also consist of small wheels. These supports (31, 35, 36) could also consist of rollers or pads sliding over the ground.
During work, the machine according to FIG. 1 is drawn by tractor (6) in direction A. Casing (9) is then driven in rotation in the direction of arrow F, around support pin (17). This driving is assured by drive shaft (16) which is connected in a way known in the art, with a cardan shaft, to the power takeoff shaft of the tractor (6). During this rotation, rollers (13) of tool-carrying arms (8) move in rolling path (24) of control cam (22). In the low portion (25) of this path (24), rollers (13) hold arms (8) in a position in which their tools (11) are almost vertical and rake the products spread on the ground. This raking zone is located essentially in the front part of the path of work tools (11). As soon as the rollers (13) are engaged in the highest portion (26) of this rolling path (24), they cause tool-carrying arms (8) to pivot around their respective longitudinal geometric axes (42) so that they lift their tools (11) over a zone of their path. These tools (11) then pivot upward and deposit the raked products in the form of a windrow. This depositing zone is located essentially on both sides of a plane P perpendicular to the direction of advance A and passing through central support pin (17). Following this depositing zone, rollers (13) come back to the low portion (25) and bring back arms (8) with tools (11) in the raking position.
In this work position, the three supports (31, 35, 36) carry the machine. They impart to it a good stability and make it possible for it to follow well the irregularities of the ground. Moreover, support (31) replaces itself automatically behind support pin (17) because of its adherence and its friction on the ground. The two supports (35, 36) which are located in front of support pin (17) are guided by rear support (31). This comes from the fact that they can pivot around vertical axes (38, 39) of their support (37) and thus follow automatically the direction imposed by the latter which is itself guided by rear support (31).
On the other hand, when tractor (6) and the machine enter a curve or a turn, rear support (31) orientates itself in the direction of movement imposed by tractor (6). Simultaneously, this support (31) causes support pin (17) to pivot around the longitudinal geometric axis (34) by connecting arm (30). The support pin (17) then automatically moves control cam (22) which is fastened to it. The cam (22) is thus also constantly oriented as a function of the direction that tractor (6) follows. Consequently, the depositing zone where the windrow is formed can vary in relation to frame (1) of the machine to stay in the vicinity of plane P which is perpendicular to direction of movement A. This depositing zone thus constantly remains at the ideal position for the formation of a regular and unscattered windrow.
Moreover, if the user wants to use the machine in the front of the tractor or in reverse to avoid turning around at the end of a field, he has no adjusting to perform. Actually, as soon as the machine is pushed, as is represented in FIG. 3, stationary support (31) automatically replaces itself behind support pin (17) and again orientates itself in the direction of movement indicated by arrow B. For the same reason, it causes support pin (17) and control cam (22) to turn by an angle of about 80°. In this way, the scraping zone of work tools (11) is again located in the front part of their path and the depositing zone is located in the vicinity of plane P' perpendicular to direction of movement B.
In the example of embodiment according to FIGS. 4 and 5, the parts common with the previous example are designated by the same references. These parts will no longer be described in detail.
It is clear from FIGS. 4 and 5 that frame (1) consists of a single beam. Raking wheel (7) is connected at the back end of frame (1) by an approximately horizontal hinge pin (43). This pin (43) is located near the upper end cf support pin (17). It is solid with frame (1) and goes through the orifices made in two lugs (45) provided on stationary cover (20). This cover also has tongue (46) making it possible to define the pivoting angle of raking wheel (7) around hinge pin (43). To do this, the tongue (46) is provided with an oblong hole (47) and a cylindrical hole (48) which can work with a bolt (49) solid with lugs (50) of frame (1). Thus, when bolt (49) is inserted through oblong hole (47) the raking wheel can pivot by a certain angle around hinge pin (43) to be able to follow the irregularities of the ground. On the other hand, when bolt (49) is engaged in cylindrical hole (48) the raking wheel is locked. This position is advantageous for transport.
In this example, the lower end of support pin (17) is also connected by a connecting arm (30) to a support (31) which rests on the ground during work. The support (31) is offset toward the back--seen in direction of movement A--in relation to pin (17) and offset laterally in relation to a vertical plane V which is directed in the direction of movement A and passes through support pin (17) (see FIG. 4). The support (31) is stationary in relation to connecting arm (30) in the horizontal plane. In the example shown, support (31) consists of a small wheel which rolls over the ground during work.
It can be seen in FIG. 4 that, in relation to plane V, the support (31) is located on the side toward which tool-carrying arms (8) move when they cross the plane V on the back half of their path--seen in direction of movement A. In the example shown, the offsetting is obtained by a column (32) connecting small wheel (31) to connecting arm (30). This offsetting could also be obtained by a slight bending of connecting arm (30). Value (d) of the lateral offsetting of small wheel (31) in relation to plane V is about 15 centimeters on the machine shown. This value (d) is such that the moment of the torque that small wheel (31) exerts on support pin (17) during movement in direction A is approximately equal to the moment of the torque exerted by rollers (13) of tool-carrying arms (8) on control cam (22). Since this latter torque can vary from one type of machine to another as a function of factors such as the number of tool-carrying arms and rollers (13), value (d) of the lateral offsetting can also vary in a range between 10 and 20 centimeter or even beyond.
Tow additional supports (35 and 36) are also connected to support pin (17). As in the previous example, the consist of pivoting small wheels located in front of support pin (17).
During work, the machine according to FIG. 4 is drawn by tractor (6) in direction A and raking wheel (7) is driven in rotation in the direction of arrow F. Support (31) is then placed automatically behind support pin (17) with a slight lateral offset in relation to plane V. In this way, it exerts a torque on support pin (17) which is approximately equal to that exerted by rollers (13) of tool-carrying arms (8) on control cam (22) which is solid with the pin (17). The two torques are balanced so that support (31) can move both against the direction of rotation F and in this direction. This makes it possible to assure a correct orientation of the assembly consisting of supports (31, 35, 36), support pin (17) and control cam (22) around geometrical axis (34) and to maintain a good stability of the assembly, even in fields exhibiting irregularities on their surface.
Thus, when tractor (6) and the machine enter a curve or a turn, rear support (31) easily orientates itself in the direction of movement. Simultaneously, it causes support pin (17) to pivot around longitudinal geometric axis (34) by connecting arm (30). The support pin (17) then automatically moves control cam (22) which is fastened to it. The control cam (22) is thus also constantly oriented as a function of the direction of movement. Consequently, the depositing zone where the windrow is formed ca vary in relation to frame (1) of the machine to stay in the vicinity of plane P which is perpendicular to the direction of movement A. This depositing zone thus remains constantly in the ideal position for the formation of a regular and unscattered windrow.
This automatic orientation of control cam (22) is also obtained when the machine is used in the front of a tractor or in reverse to avoid turning around at the end of a field.
The orientation of control cam (22) as described above is extremely simple and effective. It is performed continuously without intervention on the part of the user.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
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A haymaking machine having a frame supporting at least one raking wheel equipped with tool-carrying arms controlled during work. The raking wheel is rotatable about a support pin which carries a control cam and which is free in rotation in relation to the frame during work. The support pin is connected to at least one support which is offset in relation to the support pin in the direction of movement of the machine, with the support being stationary in relation to its connection to the support pin in the horizontal plane. The support thus assures a continuous predetermined orientation of the support pin and of control cam as a function of the direction of movement to permit formation of well-formed and regular windrows during movements of the haymaking machine both in a straight line or around curves or turns.
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CROSS RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/711,387 filed on Nov. 14, 2000 now allowed.
FIELD OF THE INVENTION
[0002] The invention relates to a coated paper made by applying a coating formulation with stable pigment slurries to the paper.
BACKGROUND OF THE INVENTION
[0003] Coating formulations or “colors” used to coat paper or paperboard products are usually applied to at least one side of a paper base stock to improve surface smoothness and to provide uniform ink reception and other generally acceptable printing properties. Typically, such formulations include pigments, binders and other additives such as dispersants, viscosity modifiers, lubricants, and chemicals that modify foaming tendencies, microbial susceptibility, pH or physical characteristics such as; color. Porous pigments, such as alumina, are important components of such coating formulations because they contribute to surface porosity of the paper and ink drainage. The porous pigments also reduce surface irregularities, thus improving paper smoothness. In general, a higher proportion of porous pigment improves the smoothness, porosity and ink-receptivity of the coating. These characteristics are particularly desirable for certain coated paper product used in inkjet printing. A commonly observed drawback, however, is that the particulate nature of the pigment limits the amount that can effectively used in the coating formulation.
[0004] The pigment is usually added during make-down of the coating formulation as a dispersion or slurry of finely divided particles, as this mode of addition is more convenient for bulk manufacturing. The use of such dispersions is, however, limited by the amount of pigment that is actually suspended in the dispersing medium at the time that it is added to the coating formulation. Because the pigments are insoluble, the pigment particles will settle out, resulting in a reduced amount of pigment per unit volume in the dispersion and the coating color. As a consequence, it is difficult to control the total solids content in the dispersion itself and in the final coating formulation. Another disadvantage is that the particles may react with certain components of the dispersion and aggregate to form a gel or sol of high viscosity, which may cause an undesirable increase in the viscosity or otherwise affect the rheological properties of the coating color.
[0005] Inventive efforts have therefore focused on the preparation of stable dispersions of pigments to be incorporated into coating formulations in a manner that allows maximum compatibility with other components of the coating formulation. Such dispersions have been prepared using an acid-based dispersant as a means of stabilizing the pigment particles in suspension. For example, U.S. Pat. No. 3,935,023 (Derolf) discloses aqueous dispersions of alumina in a hydrochloric acid-containing solution. The dispersions so formed have an alumina content of from about 18-26% weight, based on the total weight of solids, or about 54-66% parts by weight (pbw) of Al 2 O 3 per pbw of hydrochloric acid, and a specific surface area of pigment, as determined by the Brunauer, Emmett and Teller (BET) method of 150-250 m 2 /gram. The Derolf patent teaches that in order to achieve dispersions of 18-26% by weight, it is necessary to maintain an Al 2 O 3 to HCl ratio of 54-65 pbw to 1 pbw of HCl, and that when less than 53 pbw of Al 2 O 3 per pbw of HCl is used, the shelf life of the resulting product is drastically limited. Accordingly, the acid is a necessary component of Derolfs coating formulations. However, acids are hazardous and corrosive materials and are less effective at dispersing pigments. Moreover, it has been determined experimentally that using acids as the primary dispersion means does not produce slurries with a high level of pigment solids at an desired viscosities.
[0006] U.S. Pat. No. 5,518,660 (Wei) describes preparing low-viscosity colloidal dispersions of sub-micrometer alumina particles for use in ceramics manufacture that contain 0.1 to 5% by weight of a semicarbazide hydrochloride acidic compound as a dispersing agent. In this regard, the semicarbazide compound dissociates in water by releasing the HCl ligand, which, in turn acidizes the dispersion to avoid agglomeration and thereby maintaining a low viscosity. The Wei method has the short comings similar to Derolf.
[0007] As an alternative, coating formulation have been prepared by incorporating the solid pigment directly into the color formulation. For example, Japanese Patent Abstract No. JP 9314985A2 describes an aqueous coating formulation for inkjet or electrophotographic printing containing alumina hydrate, ethylenediamine-tetraacetic acid sodium as a chelating agent, an imidazolium compound as a cationic component and polyacrylamide. The process described by the patent abstract eliminates the step of dispersing the alumina hydrate and adding it to the coating formulation as a slurry. Direct introduction of a solid pigment during preparation of the coating formulation as reported in this abstract is undesirable, however, because additional steps are then required to homogenize the coating formulation and to maintain the desired Theological properties. These additional steps would increase manufacturing costs. In addition, the coating formulation may still be susceptible to the deterioration observed with respect to many dispersions, such as flocculation and gellation.
[0008] Accordingly, a need exists for a method of making and applying a coating formulation to paper wherein the coating has a high pigment solids content.
SUMMARY OF THE INVENTION
[0009] The present invention discloses a paper coated with a new coating formulation. The coating formulation comprises a stable pigment slurry prepared without an acid-based dispersant. The coating formulation may be applied to the paper using a variety of methods: In general, an aqueous cationic pigment slurry is prepared comprising an alumina pigment slurry, a nonionic wetting agent, and a cationic interfacial modifier (dispersant). The aqueous cationic pigment slurry is then added to one or more additional conventional coating ingredients, such as binders, pigments, and additives to form a coating formulation. The coating formulation is then applied to at least one side of a paper and the coating is mechanically treated.
DETAILED DESCRIPTION OF THE INVENTION
[0010] According to the present invention, a pigment slurry that is suitable for use in manufacturing paper and paperboard coating formulations may be prepared and maintained over relatively long periods without flocculation, gellation or other deterioration. The slurries of the invention may be used in a variety of applications including, but not limited to, paper and paperboard coating formulations. The slurries are formed by dispersing and homogenizing an alumina pigment, a nonionic wetting agent or nonionic polymer and a cationic interfacial modifier in an aqueous medium.
[0011] As used herein, the term “alumina pigment” includes particulate aluminum oxides and hydrated aluminum oxides in activated, calcined or fused form. Preferably, the alumina pigment may be selected from the group consisting of fumed alumina, alumina trihydroxide and pseudoboehmite. One or more of the aforementioned compounds may be included as the alumina pigment component in the present invention. A wide range of pigment particle sizes may be used, the chosen particle size being limited only in that the particles should be small enough to facilitate suspension or dispersion in an aqueous medium. In this regard, larger particulate aluminas may, if necessary, be divided, for example by jet-milling, to produce a mean particle size suited to aqueous dispersion. A typical particle size for this purpose is in the range of from about 1 to about 10 microns, preferably from about 0.05 microns to about 3 microns. An example of such a material is a pseudoboehmite manufactured by Alcoa World Chemicals Inc., and subsequently jet-milled to a particle size of about 2.0 microns. As another example, a fumed alumina having an average particle size of about 0.2 micron may be used. While it is desirable that a pigment of a particle size sufficient to permit suspension in the aqueous medium of the invention be used, the physical characteristics of the pigment are not otherwise limited. For example, an alumina pigment having a mean particle diameter of about 2 microns was used to prepare slurries according to the invention, the BET surface area, which is a measure of how finely the pigment is divided, of such a pigment may be as high as about 300 m 2 /g, typically about 270 m 2 /g, while its pore volume may be in the range of up to about 0.5 ml/g. The alumina pigment preferably represents from about 35 parts by weight to about 45 parts by weight of the aqueous slurry, based on the total weight of the slurry.
[0012] The nonionic wetting agent used in the invention is a non-particulate additive that reduces the length of time otherwise required for wetting out of the alumina pigment in the aqueous medium by eliminating the interfacial separation between the pigment particles and the water molecules in the slurry. Typically, this agent is of a molecular composition including at least one alcohol functionality, and, accordingly, may be selected from mono- or polyhydric alcohols, polyalcohols and polyols. Preferably, the nonionic wetting agent is an acetylenic alcohol such as 3,5-dimethyl-1-hexyne-3-diol, which is commercially available for example, from Air Products and Chemicals, Inc. A nonionic polymer may be included as an alternative to or in combination with the nonionic wetting agent. Such polymers are polar in nature, and function as steric blockers that prevent agglomeration of the pigment particles. Examples of appropriate nonionic polymers include nonionic polyacrylamides, such as polyvinyl pyrrolidone (PVP), and nonionic polyvinyl alcohol (PVA) polymers. The amount of nonionic wetting agent, nonionic polymer or combination thereof to be included in the slurry is from about 0.5% to about 5.0% by weight, preferably from about 2% to about 4% by weight, based on the total weight of the pigment.
[0013] The cationic slurry also includes a cationic interfacial modifier. As used herein, the term “cationic interfacial modifier” means a cationic dispersant, which acts as an antinucleation agent, or a cationic surfactant, which lowers the interfacial tension between the pigment particles and the molecules in the dispersing medium, or any combination thereof The cationic interfacial modifier includes, but is not limited to, oligomeric compounds, such as inorganic oligomers, and other organic or inorganic polymeric compounds. While not wishing to be bound by any particular theory of operation, it is postulated that the cationic dispersant or cationic surfactant facilitates stable suspension of the pigment particles in the slurry of the invention by establishing a delocalized positive charge throughout the aqueous medium. The pigment particles are thus electrostatically attracted to and separated by the cationically charged species and, as a result, do not aggregate to form larger particles that flocculate from the medium, or form gels of a viscosity so high as to reduce the spreading ability of any coating containing the pigment. This delocalized cationic charge throughout the dispersing medium, in combination with the functional effects of the other ingredients, such as the wetting effect of the nonionic wetting agent or the steric blocking effect of the nonionic polymer therefore facilitates suspension of the particles in the slurry, and may be responsible for the prolonged stability of the slurry over storage periods of up to one year or more.
[0014] Preferably, the cationic dispersant is an inorganic oligomer. One example of such a compound is an aluminum hydroxychloride oligomer sold under the trade name “SYLOJET 200A”, which is commercially available from W. R. Grace Inc. The cationic surfactant may be used instead of or in combination with a cationic dispersant. A suitable example of this component is RHODAQUAT T, which is a quaternary ammonium compound having a dispersant and antistatic effect, which is commercially available from Rhone-Poulenc Inc. The amount of either cationic dispersant or cationic surfactant that may be included in the slurry is from about 2% to about 15% by weight, preferably from about 5% to about 10% by weight of the total weight of the cationic slurry. In various embodiments of the invention, a combination of cationic dispersant or cationic surfactant may be included in the slurries. In this regard, the proportions of each of the polymer dispersant or surfactant are selected so as to provide a total amount of cationic interfacial modifier of from about 2% to about 15% by weight, preferably from about 5% to about 10% by weight, as described above.
[0015] When the alumina pigment is a fumed alumina, a supplemental dispersant such as lactic acid may optionally be added to the slurry in an amount sufficient to generate a pH of from about 2 to about 6. This reduction in pH is generally accompanied by a reduction in viscosity. This ingredient is not necessary for forming the slurries, however, in the case of fumed alumina, mixing with a cationic dispersant such as aluminum hydroxychloride oligomer as well as lactic acid enhances the dispersion of the cationically charged pigment particles in the suspension. This combination augments the dispersion of the fumed alumina to make a stable slurry having an advantageously high solids content. In this embodiment, a fumed alumina slurry with a solids content of up to about 42% weight may be obtained.
[0016] To make the slurries, the alumina pigment, nonionic wetting agent or polymer and the cationic interfacial modifier are combined in water, using any conventional mixing means, and agitated to form a slurry. While the order of combination of these ingredients is not critical, it may be desirable to first combine the pigment with the nonionic wetting agent to more easily disperse it in the aqueous carrier before adding the remaining ingredients. After mixing, the resulting slurries have been observed to have an alumina pigment concentration of up to about 67% by weight of solids. Preferably, the pigment content is in-the range of from about 42% to about 67% by weight. The viscosity of the resulting slurry is usually on the order of less than about 5000 cPs, preferably from about 500 to about 2000 cPs. as determined at 20 rpm using a Brookfield No. 4 spindle at 25° C.
[0017] Other additives typically used in paper and paperboard pigment formulations may be added to the pigment slurries of the invention. Such additives include, without limitation, one or more ingredients selected from the group consisting of other pigments, brighteners, defoamers, binders and other conventional slurry additives.
[0018] The slurries may be implemented in a wide range of applications where pigments are used. They are particularly suitable for forming pigment-rich coating formulations for paper and paperboard coating applications when combined with other coating components. The amount of slurry used in such coating formulations is that which is effective to provide the maximum amount of alumina pigment in the final coated product. When the slurry is used in a coating formulation, the coating may be applied to at least one surface of a paper or paperboard stock by any conventional means known in the art, for example using a roll, blade, bar or pad coater, and the excess metered off to form a layer of uniform thickness on the surface of the stock. Other coating methods may also be used. For example, the coating may be applied as a metered film or by cast coating. After coating, the layer of coating may then be dried, and the coated stock finished by any conventional means, such as calendaring or other suitable mechanical treatments. As but one example of their application in paper manufacture, the slurries may be used in conjunction with a combination of porous and non-porous pigments that yield excellent print performance on original equipment manufacturers' (OEM) inkjet printers. In this regard, it has been observed that the performance of coatings made with the cationic pigment slurries of the invention demonstrate superior printing performance and hold out of anionic inkjet inks.
[0019] The slurries formed according to the invention are particularly compatible with other strongly cationic materials that may be used in coating formulations. Non-limiting examples of such materials include cationic latex emulsions and Poly(DADMAC), which is a cationic quaternary amine.
[0020] Moreover, the cationic pigment slurries of the invention are highly stable. As used herein, the term “stable” means that the slurries may be stored after preparation without subsequent mixing or agitation for relatively long periods of up to a year or more, without the occurrence of gelling, flocculation or other undesirable deterioration is eliminated or significantly reduced. This stability may be attributed, in part, to the fact that an acid-based dispersant is not used, and also to the stabilizing effects of the cationic interfacial modifier and the nonionic wetting agent and/or polymer.
[0021] The following examples are representative of, but are in no way limiting as to the scope of the invention.
EXAMPLE 1
[0022] Particles of pseudoboehmite alumina were jet-milled to a mean particle size of about 2.0 microns, to provide a BET specific surface area of approximately 270 m 2 /g and a pore volume of about 0.5 ml/g. To about 55 grams of water was added approximately 1.0 gram of SURFYNOL 104, an acetylenic alcohol (Air Products & Chemicals Inc.), and about 3.15 grams of RHODAQUAT T (Rhone Poulenc) as a cationic surfactant, to form an aqueous solution. The milled pigment particles were added to this solution and the mixture agitated for about 10 minutes at a temperature of about 90° F. to form a slurry with a total pigment solids content of about 4% by weight. The slurry was maintained in a stable condition without appreciable settling for a period of about 2 months.
EXAMPLE 2
[0023] A slurry of fumed alumina was prepared by combining 42 parts fumed alumina with 8 parts of an aluminum hydroxychloride oligomer (SYLOJET 200 A). The resulting slurry had a total pigment solids content of about 42% by weight.
EXAMPLE 3
[0024] A slurry was prepared by mixing 70 parts alumina trihydrate pigment (HYDRALCOAT, Alcoa World Chemicals), 8 parts RHODAQUAT T and 2 parts SURFYNOL. The slurry had a total pigment solids content of about 70% by weight.
[0025] It is believed that the present invention includes many other embodiments that may not be herein described in detail, but would nonetheless be appreciated by those skilled in the art from the disclosures made. Accordingly, this disclosure should not be read as being limited only to the foregoing examples or only to the designated preferred embodiments.
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The present invention discloses a paper coated with a new coating formulation. The coating formulation comprises a stable pigment slurry prepared without an acid-based dispersant. The coating formulation may be applied to the paper using a variety of methods: In general, an aqueous cationic pigment slurry is prepared comprising an alumina pigment slurry, a nonionic wetting agent, and a cationic interfacial modifier (dispersant). The aqueous cationic pigment slurry is then added to one or more additional conventional coating ingredients, such as binders, pigments, and additives to form a coating formulation. The coating formulation is then applied to at least one side of a paper and the coating is mechanically treated.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/768,568, filed Feb. 25, 2013, the entire disclosure of which is incorporated by reference herein.
BACKGROUND
1. Technical Field
The present disclosure relates to surgical instruments and, more particularly, to access assemblies for providing access to internal body cavities, tissues and organs.
2. Background of Related Art
Laparoscopic surgical procedures are minimally invasive procedures in which operations are carried out within the body by means of elongated instruments inserted through small incisions in the body. Laparoscopic procedures are desirable in that they improve patient recovery time and minimize hospital stays as compared to open surgical procedures. Laparoscopic procedures also leave minimal scarring (both internally and externally) and reduce patient discomfort during the recovery period.
During a typical laparoscopic, or minimally invasive procedure, surgical objects, such as surgical access devices, e.g., trocar and cannula assemblies, or endoscopes, are inserted into the patient's body through the incision in tissue. In general, prior to the introduction of the surgical object into the patient's body, insufflation gasses are used to enlarge the area surrounding the target surgical site to create a larger, more accessible work area. Accordingly, the maintenance of a substantially fluid-tight seal is desirable so as to prevent the escape of the insufflation gases and the deflation or collapse of the enlarged surgical site.
Due to the relatively small interior dimensions of the cannulas and/or access ports used in laparoscopic procedures, only elongated, small diametered instrumentation may be used to access the internal body cavities and organs. The manipulation of such instruments within the internal body is similarly limited by both spatial constraints and the need to maintain the body cavity in an insufflated state.
SUMMARY
In accordance with the present disclosure, a cannula assembly is provided. The cannula assembly includes a cannula and an obturator. The cannula includes an elongated shaft dimensioned to access tissue. The elongated shaft has a lumen extending therethrough, defines a longitudinal axis and has proximal and distal ends. The elongated shaft further includes a first shaft segment having a first pre-determined configuration and a second shaft segment having a second pre-determined configuration that is different from the first pre-determined configuration. The obturator includes an elongated body adapted for insertion through the lumen of the elongated shaft. The elongated body has proximal and distal ends. The elongated body further includes a first body segment having a configuration in general accordance with the first pre-determined configuration of the first shaft segment and a second body segment selectively adaptable to conform to the second pre-determined configuration of the second shaft segment upon insertion through the lumen of the elongated shaft.
In one embodiment, the first pre-determined configuration of the first shaft segment defines a general linear segment and the first body segment of the elongated body defines a generally corresponding linear segment.
In another embodiment, the second pre-determined configuration of the second shaft segment defines a general arcuate segment. Upon insertion of the elongated body through the lumen of the elongated shaft, the second body portion of the elongated body is positioned in the second pre-determined configuration having a generally corresponding arcuate segment.
In yet another embodiment, the second shaft segment of the elongated shaft is disposed adjacent the distal end of the elongated shaft. Alternatively, the second shaft segment of the elongated shaft may be disposed intermediate the proximal and distal ends of the elongated shaft.
In still another embodiment, the distal end of the elongated body defines a conical-shaped configuration to facilitate advancement through tissue.
In still yet another embodiment, the elongated body of the obturator defines a longitudinal axis. The second body segment of the elongated body is initially positioned in general alignment with the longitudinal axis. However, upon insertion of the elongated body through the lumen of the elongated shaft, the second body segment is positioned in general oblique relation with the longitudinal axis in general accordance with the second pre-determined configuration of the second shaft segment.
A surgical access system is also provided in accordance with the present disclosure. The surgical access system includes an anchor member and a cannula assembly. The anchor member is positionable within a passage in tissue. The anchor member includes a compressible material and defines a proximal end, a distal end and an intermediate portion. The anchor member is adapted to transition between an at least partially compressed condition to facilitate introduction within the passage in tissue and an at least partially expanded condition to substantially anchor the anchor member relative to the tissue. The anchor member further includes one or more ports extending therethrough. The cannula assembly includes a cannula defining a longitudinal axis and a lumen extending therethrough. The cannula includes a cannula segment offset with respect to the longitudinal axis.
The access system may include an obturator having an elongated obturator body adapted for insertion through the lumen of the cannula. The obturator body has a flexible body segment adapted to follow the path defined by the offset cannula segment. The elongated body has an end dimensioned to extend beyond the cannula and configured to facilitate advancement of the obturator and cannula through the one or more ports of the anchor member with the internal surfaces defining the at least one port of the anchor member establishing a substantial seal about the cannula.
In embodiments, the cannula assembly may be configured according to any of the embodiments of the cannula assembly discussed above.
In another embodiment, a surgical instrument having a flexible shaft segment and an end effector adapted to perform a surgical task is dimensioned for advancement through the lumen of the cannula in the absence of the obturator whereby the flexible shaft segment follows the path defined by the offset cannula segment.
BRIEF DESCRIPTION OF THE DRAWINGS
Various embodiments of the subject instrument are described herein with reference to the drawings wherein:
FIG. 1 is a side, cross-sectional view of one embodiment of a pre-bent access instrument in accordance with the present disclosure;
FIG. 2 is a side plan view of a partially-bendable obturator for use with the pre-bent access instrument of FIG. 1 ;
FIG. 3 is a side, cross-sectional view showing the obturator of FIG. 2 inserted through the pre-bent access instrument of FIG. 1 ;
FIG. 4A is an exploded, perspective view of another embodiment of a pre-bent access instrument in accordance with the present disclosure;
FIG. 4B is a perspective view of the pre-bent access instrument of FIG. 4A illustrating an obturator inserted therethrough;
FIG. 5 is a side view of a compressible port anchor in accordance with the present disclosure configured for insertion into an incision in tissue;
FIG. 6 is a side view of the compressible port anchor of FIG. 5 shown inserted through the incision in tissue and having a pre-bent access instrument inserted through a port thereof; and
FIG. 7 is a side view of the compressible port anchor of FIG. 5 shown inserted through the incision in tissue with a pre-bent access instrument inserted through a port thereof and a flexible surgical grasper inserted through the pre-bent access instrument.
DETAILED DESCRIPTION
Embodiments of the presently disclosed surgical instruments will now be described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical structural elements. As shown in the drawings and described throughout the following description, as is traditional when referring to relative positioning on a surgical instrument, the term “proximal” or “trailing” refers to the end of the apparatus which is closer to the user and the term “distal” or “leading” refers to the end of the apparatus which is further away from the user.
Turning now to FIG. 1 , a surgical instrument according to the present disclosure is shown generally indentified by reference numeral 10 . Access instrument 10 includes an elongated shaft 12 having a proximal end 14 , a distal end 16 and defining a lumen, or passageway 20 therethrough. Access instrument 10 may be configured as an access portal, e.g., a trocar or a cannula, for providing access to internal body cavities and organs. More specifically, surgical instruments, fluids and/or medicaments may be inserted through lumen 20 of access instrument 10 for use at an internal surgical site. Further, a seal member 30 may be disposed at proximal end 14 of shaft 12 for sealingly engaging an instrument (or instruments), e.g., an obturator 50 (see FIG. 2 ), inserted through lumen 20 .
Elongated shaft 12 of access instrument 10 includes a linear portion 17 and an arcuate, or curved portion 18 . Linear portion 17 is disposed about longitudinal axis “X,” while curved portion 18 bends, curves off, or is obliquely arranged with respect to longitudinal axis “X.” Although a specific configuration of curved portion 18 is shown in FIG. 1 , it is envisioned that curved portion 18 may define various curved, angled, or other bent configurations. Elongated shaft 12 may be formed from any suitable rigid, or semi-rigid medical grade material, e.g., stainless steel, or other suitable bio-compatible materials, e.g., polymeric materials. It is also envisioned that elongated shaft 12 may be formed at least partially from a shape memory material which undergoes a shape-transformation when subject to body temperatures, thereby shaping the surgical instrument, e.g., access instrument 10 , to a desired pre-bent, or curved configuration.
An obturator 50 for use with access instrument 10 is shown in FIG. 2 . Obturator 50 includes a shaft 52 having a proximal end 54 and a distal end 56 and is configured for insertion through lumen 20 of access instrument 10 . A hub 55 is disposed at proximal end 54 of shaft 52 , while distal end 56 of shaft 52 includes a pointed distal tip 57 .
Shaft 52 of obturator 50 includes a relatively rigid portion 58 and a less-rigid, or flexible portion 59 . Rigid portion 58 of shaft 52 may be formed from any suitable medical grade material, e.g., stainless steel, or other suitable rigid bio-compatible material, e.g., polymeric materials. As shown in FIG. 2 , flexible portion 59 of shaft 52 may be formed from a spring coil 60 or, alternatively, flexible portion 59 of shaft 52 may be formed from bio-compatible flexible tubing (not shown) or any other suitable resiliently flexible material. Further, flexible portion 59 may define a length that is equal to, or greater than a length of curved portion 18 of access instrument 10 , such that as, shown in FIG. 3 , obturator 50 is positionable within lumen 20 of access instrument 10 to conform to the configuration, or shape of access instrument 10 .
With continued reference to FIG. 2 , rigid portion 58 of shaft 52 is coaxially disposed about longitudinal axis “X,” and provides structural support to shaft 52 , while flexible portion 59 is capable of being bent or angulated relative to the longitudinal axis “X” of shaft 52 in any radial direction to conform obturator 50 to a desired configuration, e.g., the pre-bent configuration of shaft 12 of cannula or access instrument 10 . However, although flexible portion 59 is radially deflectable, it is envisioned that flexible portion 59 of shaft 52 may be substantially rigid, in the axial direction.
FIG. 3 illustrates obturator 50 inserted through and positioned within lumen 20 of access instrument 10 . As shown, pointed distal tip 57 of obturator 50 extends distally from distal end 16 of access instrument 10 , while hub 55 of obturator 50 extends proximally from proximal end 14 of access instrument 10 . More particularly, pointed distal tip 57 allows for penetration, or dissection through tissue. Flexible portion 59 of obturator 50 is deflected off axis or angulated relative to longitudinal axis “X” to conform to the curved configuration of curved portion 18 of shaft 12 of access instrument 10 . However, due to the axial stiffness, or rigidity of flexible portion 59 of shaft 52 , the shaft 52 is not compressed upon distal advancement of access instrument and obturator 10 and 50 , respectively, through tissue. Accordingly, with obturator 50 positioned within access instrument 10 , the access assembly may be advanced distally, lead by pointed distal tip 57 of obturator 50 , through tissue to an internal surgical site. Obturator 50 may then be removed from access instrument 10 such that lumen 20 provides an access port, or cannula, for performing a minimally-invasive surgical procedure at the internal surgical site.
Turning now to FIG. 4A , in one embodiment, trocar, or access instrument 100 includes respective proximal and distal ends 102 , 104 , a shaft or elongate member 106 disposed therebetween and seal housing 108 . Access instrument 100 is similar to access instrument 10 discussed above.
Elongate member 106 of access instrument 100 includes a straight, or linear portion 107 a and a curved, or bent portion 107 b extending along at least a portion of the length thereof. Elongate member 106 further defines an opening 110 extending longitudinally therethrough that is dimensioned to permit the passage of surgical instrumentation therethrough, such as obturator 500 ( FIG. 4B ). As in the previous embodiment, obturator 500 includes a flexible portion 509 ( FIG. 4B ) configured to conform to curved portion 107 b of access instrument 100 when inserted therethrough and a rigid portion 508 to provide structural support to obturator 500 . Obturator 500 is similar to obturator 50 ( FIG. 2 ).
Access instrument 100 includes seal housing 108 which is associated with or mounted to housing 103 of the access instrument 100 . Seal housing 108 includes an instrument seal 112 that is adapted to receive surgical instrumentation inserted into longitudinal opening 110 so as to form a substantially fluid-tight seal therewith. Access instrument 100 may further includes a closure valve 114 within seal housing 108 or cannula housing 103 that is biased toward a closed position, but is adapted to open upon the introduction of the surgical instrumentation inserted into longitudinal opening 110 to allow the surgical instrumentation to pass therethrough. In the closed position, i.e., in the absence of surgical instrumentation, closure valve 114 creates a fluid-tight seal to, for example, inhibit insufflation gas for escaping through longitudinal opening 110 of access instrument 100 .
Turning now to FIG. 4B , access instrument 100 is shown with obturator 500 inserted therethrough. More specifically, pointed distal tip 507 of obturator 500 extends distally from distal end 104 of access instrument 100 , while hub 505 of obturator 500 extends proximally from proximal end 102 of access instrument 100 . Further, flexible portion 507 of obturator 500 is bent, or conformed to pre-bent curved portion 107 b of access instrument 100 . From this position shown in FIG. 4B , the access assembly may be inserted through tissue or, as will be described below, may be inserted through an access portal, e.g., access portal 1000 ( FIG. 5 ).
With reference now to FIGS. 5-6 , a seal anchor member 1000 for use during a minimally-invasive surgical procedure is shown. Seal anchor member 1000 defines a longitudinal axis “X” and has a proximal end 1020 , a distal end 1040 , and an intermediate portion 1060 that is disposed between the proximal and distal ends 1020 , 1040 , respectively. Seal anchor member 1000 further includes one or more ports 1080 that extend longitudinally therethrough between proximal and distal ends 1020 , 1040 , respectively, thereof.
Seal anchor member 1000 may be formed from a suitable foam material, e.g., a polyisoprene foam, having sufficient compliance to form a seal about one or more surgical instruments, e.g., access instrument 100 , inserted through one of ports 1080 and also to establish a sealing relation with surrounding tissue. It is envisioned that seal anchor member 1000 be sufficiently compliant to accommodate off axis motion of surgical instrumentation, e.g., access instrument 100 , inserted therethrough. Seal anchor 1000 may be the port anchor disclosed in commonly assigned U.S. patent application Ser. No. 12/244,024, filed Oct. 2, 2008, the entire contents of such disclosure being incorporated herein.
As shown in FIGS. 5-6 , proximal and distal ends 1020 , 1040 of seal anchor member 1000 define substantially planar surfaces, although it is envisioned that either or both of proximal and distal ends 1020 , 1040 , respectively, of seal anchor member 1000 may define surfaces that are substantially arcuate to assist in the insertion of seal anchor member 1000 through an incision “I” in tissue “T.”
Intermediate portion 1060 of seal anchor member 1000 extends longitudinally between proximal and distal ends 1020 , 1040 , respectively, of seal anchor member 1000 . Intermediate portion 1006 varies in diameter along a length thereof. Accordingly, seal anchor member 1000 defines a cross-sectional dimension that varies along a length thereof to facilitate the anchoring of seal anchor member 1000 within an incision in tissue. In one embodiment, seal anchor member 1000 defines an “hour-glass” shape or configuration to assist in anchoring seal anchor member 1000 within an incision in tissue. In cross-section, intermediate portion 1060 may exhibit any suitable configuration, e.g., substantially circular, oval or oblong.
Each port 108 extending through anchor seal member 1000 is configured to removably receive a surgical instrument (e.g., access instrument 10 ) therethrough. Prior to the insertion of surgical instrumentation, each of ports 1080 is disposed in a first state wherein each of ports 1080 defines a first or initial dimension D 1 ( FIG. 6 ). Initial dimension D 1 ( FIG. 6 ) may be about 0 mm such that the escape of insufflation gas (not shown) through ports 1080 of seal anchor member 1000 in the absence of a surgical instrument inserted therethrough is substantially inhibited. For example, each port 1080 may be configured as a slit extending longitudinal through seal anchor member 1000 . Upon the introduction of surgical instrumentation through one (or more) of ports 1080 , port 1080 transitions to a second state in which port 1080 defines a second, larger dimension D 2 ( FIG. 6 ) that substantially approximates the diameter of the surgical instrument disposed therethrough such that a substantially fluid-tight seal is formed therearound and such that the escape of insufflation gas (not shown) through port 1080 of seal anchor member 1000 is substantially inhibited.
The use and function of access instrument 100 in conjunction with seal anchor member 1000 will be discussed during the course of a typical minimally invasive procedure with reference to FIGS. 4A-7 . However, it is envisioned that the cannula assembly, i.e., access instrument 100 and obturator 500 , may be configured for use independently of seal anchor member 1000 and/or in conjunction with any other suitable seal member (not shown).
Initially, the peritoneal cavity (not shown) is insufflated with a suitable biocompatible gas, e.g., CO 2 gas, such that the cavity wall is raised and lifted away from the internal organs and tissue housed therein, providing greater access thereto. The insufflation may be performed with an insufflation needle or similar device, as is conventional in the art. Either prior or subsequent to insufflation, an incision “I” is created in tissue “T”, the dimensions of which may be varied dependent upon the nature of the procedure.
Prior to the insertion of seal anchor member 1000 within the incision in tissue, seal anchor member 1000 is in its expanded condition in which the dimensions thereof inhibit the insertion of seal anchor member 1000 into the incision “I” in tissue “T.” To facilitate insertion, the clinician transitions seal anchor member 1000 into the compressed condition by applying a force thereto, e.g., by squeezing seal anchor member 1000 . This applied force acts to reduce the radial dimensions of the proximal and distal ends 1020 , 1040 , respectively, of anchor seal member 1000 and similarly reduces the radial dimension of intermediate portion 1060 such that seal anchor member 1000 may be inserted into the incision “I” in tissue “T.” Subsequent to insertion, distal end 1040 of seal anchor member 1000 is positioned beneath tissue “T” at which time seal anchor member 1000 may be allowed to transition from the compressed condition back to the expanded condition by removing the force thereon.
During the transition from the compressed condition to the expanded condition, the dimensions of seal anchor member 1000 are increased such that intermediate portion 1060 creates an internal biasing force that is directed outwardly and exerted upon surrounding tissue, thereby creating a substantially fluid-tight seal between the seal anchor member 1000 and surrounding tissue, while proximal and distal ends 1020 , 1040 , respectively, extend radially from the incision “I” in tissue “T” on the respective external and internal surfaces thereof. Thus, once in position, seal anchor member seals, or inhibits the escape of insufflation gas from the internal surgical site.
Once seal anchor member 1000 is positioned within the incision “I” in tissue “T,” as described above, one or more surgical instruments may be inserted through ports 1080 . Surgical instrumentation introduced through one of ports 1080 may be any suitable surgical instrument and, accordingly, may vary in size. Suitable surgical instruments may include graspers, forceps, clip-appliers, staplers, etc. Other access instruments such as, for example, access instrument 100 , may also be introduced through seal anchor member 1000 such that additional surgical instrumentation may be inserted through access instrument 100 (once obturator 500 has been removed from lumen 110 of access instrument 100 ) and advanced to the surgical site.
More specifically, with obturator 500 inserted trough access instrument 100 , as shown in FIG. 4B , the access assembly may be inserted, lead by pointed distal tip 507 of obturator 500 , through one of ports 1080 , enlarging port 1080 and thereby transitioning port 1080 into the second state in which port 1080 defines a second dimension D 2 that substantially approximates the diameter of access instrument 100 , creating a substantially fluid tight seal about access instrument 100 and inhibiting the escape of insufflation gas (not shown) through port 1080 of seal anchor member 1000 , as discussed above. Access instrument 100 may then be advanced into position adjacent the internal surgical site.
With reference now to FIG. 7 , once access instrument 100 is disposed through access portal 1000 , as shown in FIG. 6 , and is positioned as desired for the particular minimally-invasive surgical procedure to be performed at the internal surgical site, obturator 500 may be removed from access instrument 100 . As such, other surgical instrumentation, e.g., surgical grasper “S,” may be inserted through opening 110 of access instrument 100 to perform a minimally-invasive surgical procedure at the internal surgical site. One surgical instrument contemplated will have a flexible section adapted to conform or follow the pre-bent or curved configuration of access instrument 10 . Such instruments with flexible shafts are disclosed in commonly assigned U.S. Pat. Nos. 4,473,077 and 7,546,993 and U.S. Patent Publication No. 2009/0090765, the entire contents of each disclosure being incorporated herein. As mentioned above, instrument seal 112 maintains a fluid-tight seal about surgical grasper “S” when inserted through access instrument 100 . Additionally, the pre-bent, or curved configuration of access instrument 100 helps prevent interference, tangling, or “chop-sticking” of surgical instrumentation inserted through the various ports 1080 of seal anchor member 1000 , particularly where multiple surgical instruments are inserted through seal anchor member 1000 and/or where multiple seal ports, e.g., seal anchor members 1000 , are used.
From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
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A cannula assembly includes a cannula and an obturator. The cannula includes an elongated shaft dimensioned to access tissue. The elongated shaft has a lumen extending therethrough. The elongated shaft includes a first shaft segment having a first pre-determined configuration and a second shaft segment having a second pre-determined configuration different from the first pre-determined configuration. The obturator includes an elongated body adapted for insertion through the lumen of the elongated shaft. The elongated body includes a first body segment having a configuration in general accordance with the first pre-determined configuration of the first shaft segment and a second body segment selectively adaptable to conform to the second pre-determined configuration of the second shaft segment upon insertion through the lumen of the elongated shaft.
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FIELD OF THE INVENTION
This invention relates to a semiconductor memory device and more particularly, to a semiconductor memory device which includes a plurality of bit line pairs and a plurality of sense amplifiers for amplifying potential differences in each pair of bit lines respectively.
DESCRIPTION OF THE PRIOR ART
A semiconductor memory device includes a memory cell array comprising plural memory cells arranged in the form of an array, plural bit lines connected respectively to these memory cells, and plural word lines connected similarly to the memory cells. Each of the plural bit lines of the memory cell array comprises a pair of bit lines which are complementarily applied with a certain voltage and a sense amplifier is provided for each of the bit line pairs. At the time of reading or writing operation or at the time of refreshing operation, the sense amplifiers are activated corresponding to sense amplifier activation signals to amplify the potential differences between two bit lines of each bit line pair.
Along with the high integration of such semiconductor memory device in recent years, however, the interval between the bit lines has become extremely narrow, and as a result, the parasitic capacitance therebetween increases to cause various problems. More particularly, when the potential difference between a pair of bit lines is smaller than a predetermined value due to fluctuation of characteristics of a transistor or a capacitance element of a memory cell, the output of the sense amplifier connected to the particular bit line pair delays in rise compared to other sense amplifiers (the output from a sense amplifier is quicker in rise as the potential difference between the bit lines of the pair increases). On the other hand, if the potential difference applied on a bit line pair adjacent to the pair of bit lines in question is larger than the predetermined value, then there is no delay in the sense amplifier connected to the latter pair of bit lines. But due to the parasitic capacitance between the pairs of the bit lines, crosstalk will occur between the output voltages from the two bit line pairs in response to the sense amplifier activation signals to cause errors in a reading out operation.
BRIEF SUMMARY OF THE INVENTION
Object of the Invention
An object of this invention is to provide a semiconductor memory device which can reduce the crosstalk between pairs of bit lines.
SUMMARY OF THE INVENTION
The semiconductor memory device according to this invention includes a memory cell array which comprises plural memory cells in the form of an array, plural bit line pairs and plural word lines which are connected respectively to the memory cells, sense amplifiers which are provided one each for each pair of bit lines and which amplify the potential difference between two bit lines of a pair in response to an activation signal, and transfer gates which divide the bit line pairs into at least two groups corresponding to a control signal. The semiconductor device is characterized in that the sense amplifiers connected to two adjacent pairs of bit lines are arranged axisymmetrical with respect to the transfer gates.
The semiconductor memory device preferably includes a power source line which supplies a constant potential and a connector means which controls the connection between the bit line pairs and the power source line in response to a precharge signal.
BRIEF DESCRIPTION OF THE DRAWINGS
The above-mentioned and other objects, features and advantages of this invention will become more apparent by reference to the following detailed description of the invention taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a circuit diagram to show the first embodiment of the semiconductor memory device according to this invention;
FIG. 2 is a waveform chart to explain the operations of the semiconductor device shown in FIG. 1;
FIG. 3 is a circuit diagram to show the second embodiment of the semiconductor memory device according to this invention;
FIG. 4 is a waveform chart to explain the operations of the semiconductor memory device shown in FIG. 3;
FIG. 5 is a circuit diagram to show the third embodiment of the semiconductor memory device according to this invention;
FIG. 6 is a waveform chart to explain the operations of the semiconductor memory device shown in FIG. 5;
FIG. 7 is a circuit diagram to show the fourth embodiment of the semiconductor memory device according to this invention; and
FIGS. 8 and 9 are waveform charts to explain the operations of the semiconductor memory device shown in FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, a memory cell array in this embodiment comprises plural memory cells MC each of which comprises one N channel transistor and one capacitor element and which are arranged in the form of an array in rows and columns (in other words, it comprises one-transistor-one capacitor type cells MC arranged in the form of an array). The bit lines are grouped into pairs (e.g. BL1a/BL1b, BL2a/BL2b , . . . ) each of which is connected respectively to a sense amplifier SA (e.g. SA1, SA2 , . . . ). In order to avoid those sense amplifiers connected to adjacent bit line pairs from being arranged adjacent to one another, they are arranged in a region along the side parallel to a word line of the memory cell array (i.e. the region B1 of FIG. 1) and in a region along the side which is axisymmetrical to the first side (i.e. the region B2 of FIG. 1). More specifically, sense amplifiers SA1, SA3 , . . . , Sam which are respectively connected to the bit line pair BL1a/BL1b, the bit line pair BL3a/BL3b not adjacent to the first pair , . . . and BLma/BLmb are arranged in the region B1 on the upper side of the figure while sense amplifiers SA2, SA4 , . . . respectively connected to the bit line pair BL2a/BL2b, and BL4a/BL4b , . . . are arranged in the region B2 on the lower side of the figure.
The sense amplifiers SA1 through SAm are activated with sense amplifier activation signals φS to amplify the potential difference between the bit lines in a pair such as between BL1a and BL1b.
The bit lines (BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb are respectively connected at the center thereof to the source/drain of transfer gate transistors Q1a/Q1b, Q2a/Q2b, and Qma/Qmb which are controlled ON/OFF in response to a control signal φC supplied to the gates. The memory cell array is divided into the regions A1 and A2 by these transfer gate transistors Q1a/Q1b through Qma/Qmb.
The word lines of this embodiment comprise the word lines W1-1, W1-2 , . . . , W1-n arranged in the region A1 and the word lines W2-1, W2-2 , . . . , W2-n arranged in the region A2 (in this embodiment, the number of the word lines arranged in the region A1 is the same as that in the region A2).
Precharge transistors QP1a/QP1b, QP2a/QP2b , . . . , QPma/QPmb are provided between the bit line pairs BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb and a power source line VHL which is maintained at a fixed potential VH, and those transistors are controlled ON/OFF by precharge signals φP.
Referring now to FIGS. 1 and 2, when a precharge signal φP is shifted from a high to low level, all the precharge transistors QP1a/QP1b, QP2a/QP2b , . . . , QPma/QPmb become off-state to separate all the bit lines from the power source lines VHL electrically.
A line decoder (not shown) selects one word line (description will be given to the case where the word line W1-1 is selected herein) to shift the potential thereof to a high level. The data stored in the memory cell MC connected to the selected word line W1-1 are respectively represented by the potentials of respective bit lines (see the time t21 in FIG. 2). For instance, if a data of low level is stored in a memory cell connected to the bit line BL1a and the word line W1-1, the potential of the bit line BL1a becomes slightly .lower than the potential VH, but if the data of high level is stored in the same memory cell, the potential of the bit line BL1a becomes slightly higher than VH conversely. (FIG. 2 shows the case where a low level data is stored).
Subsequently, when the control signal φC becomes from high to low level, all the transfer gate transistors Q1a/Q1b, Q2a/Q2b , . . . , Qma/Qmb are placed in an off-state to separate electrically all the bit lines into those in the region A1 and those in the region A2. More particularly, the bit line pairs BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb are divided into those electrically connected to the sense amplifiers SA1 through SAm and those separated electrically from the aforementioned sense amplifiers. As the sense amplifiers which are connected to the adjacent bit line pairs are, as mentioned above, arranged in two different regions respectively along the two axisymmetrical sides or in the regions B1 and B2 of FIG. 1, the bit line pair adjacent to a bit line pair connected electrically to a sense amplifier is separated electrically from the sense amplifier which is connected to a bit line pair adjacent to said first bit line pair. More specifically, as the control signal φC is shifted from a high to low level, the sense amplifier SA2 becomes connected to the bit line pair BL2a/BL2b in the region A2, but the sense amplifiers SA1 and SA3 are separated electrically by the transfer gate transistors Q1a/Q1b and Q3a/Q3b from the bit line pairs BL1a, BL1b, BL3a and BL3b adjacent to above-mentioned bit line portions in the region A2.
As the sense amplifier activation signal φS is shifted to a high level (at the time t22 in FIG. 2), all the sense amplifiers SA1, SA2, SA3 , . . . , SAm are activated to amplify the potential difference between the bit lines of each pair, BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb. At this time point, as those bit line pairs are divided into two groups by the transfer gate transistors Q1a/Q1b, Q2a/Q2b , . . . , Qma/Qmb, only the output voltage from one half of the bit line pairs which are directly connected to the sense amplifiers is amplified by the sense amplifiers. As bit line pairs adjacent to the bit line pair which is electrically connected to a sense amplifier are electrically separated from the sense amplifier, the sense amplifier is not affected by crosstalk from the adjacent bit line pairs immediately after the activation signal φS is shifted to a high level.
For example, even though the potential difference between the bit lines in the pair BL2a/BL2b in the region A2 is amplified by the sense amplifier SA2, those between the lines in the pairs BL1a/BL1b, and BL3a/BL3b adjacent to the pair in the same region A2 are not amplified, to thereby eliminate the effect of crosstalk (see BL1(A2) and BL2(A1) in FIG. 2).
After the potential difference in the bit line pair BL2a/BL2b is fully amplified by the sense amplifier SA2 and the control signal φC reaches a high level (at the time t23 in FIG. 2), all the transfer gate transistors Q1a/Q1b through Qma/Qmb are turned ON, and the bit lines BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb which have been divided into two groups in the regions A1 and A2 are electrically connected again to amplify the potential differences in all of the bit line pairs.
As the potentials of the other half of the bit line pairs which are eventually connected by the transfer gate transistors Q1a/Q1b through Qma/Qmb were not amplified up until this moment (e.g. BL1(A2), BL2(A1) etc.), potentials of the bit line pairs BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb either drop respectively from Vcc by 1/4 Vcc or increases by 1/4 Vcc from GND immediately after the transfer gate transistors Q1a/Q1b through Qma/Qmb are turned ON, but will shortly be returned to the levels of Vcc and GND by the sense amplifiers SA1 through SAm. Subsequently, data at a new level amplified by the sense amplifiers SA1 through SAm will be stored in the memory cells MC.
Then, when the potential of the selected word line (W1-1 as mentioned above) reaches a low level, the connection between the bit lines and the memory cells MC is cut off. When the sense amplifier activation signal φS becomes low, all the sense amplifiers become inactivated. When the precharge signal φP becomes high, the precharge transistors QP1a/QP1b through QPma/QPmb are turned ON to electrically connect all the bit lines with the power source line VHL and to make their potentials shift to the fixed potential VH.
Referring now to FIG. 3, the second embodiment of this invention differs from the first embodiment only in that the control signal φC of the first embodiment is replaced with the control signals φ1 and φ2, the precharge signal φP with the precharge signals φP1 and φP2, and the sense amplifier activation signal φS with the sense amplifier activation signals φS1 and φS2. The control signal φC1 is supplied to the gate electrodes of the transfer gate transistors Q1a/Q1b, Q3a/Q3b , . . . of the bit line pairs connected to the sense amplifiers SA1, SA3 , . . . , SAm arranged in the region B1. The control signal φC2 is supplied to the gates of the transfer gate transistors Q2a/Q2b, and Q4a/Q4b of the bit line pairs connected to the sense amplifiers SA2, SA4 , . . . arranged in the region B2. Similarly, the sense amplifier activation signal φS1 is supplied to the sense amplifiers SA1, SA3 , . . . in the region B1 while the signal φS2 controls the activation of the sense amplifiers SA2, SA4 , . . . in the region B2. The precharge signal φP1 is supplied to the precharge transistors QP2a/QP2b, QP4a/QP4b , . . . connected to the sense amplifiers SA1, SA3 , . . . SAm in the region B1 while the signal φP2 is supplied to the precharge transistors QP1a/QP1b, QP3a/QP3b , . . . connected to the sense amplifiers SA2, SA4 , . . . in the region B1. Except for the modification made on the first embodiment to allow the three groups of the signals φC1/φC2, φP1/φP2, and φS1/φS2 to be supplied, the second embodiment is identical to the first embodiment and detailed description is omitted.
Description will now be made on the case where a word line W1-1 in the region A1 is selected referring to FIG. 4.
The control signal φP1 which is generated based on the data in the row decoder when the word line W1-1 is selected is shifted to a low level, and the transfer gate transistors Q1a/Q1b, Q3a/Q3b , . . . of the bit line pairs BL1a/BL1b, BL2a/BL2b , . . . BLma/BLmb connected respectively to the sense amplifiers SA1, SA3 , . . . SAm in the region B1 are turned OFF. As the precharge signal φP1 is shifted to a low level, the bit line pairs BL2a/BL2b, BL4a/BL4b , . . . connected respectively to the sense amplifiers SA2, SA4 , . . . in the region B2 are electrically separated from the power source lines VHL. Under this state, the precharge signal φP2 is maintained at a high level.
In this state, out of the bit line pairs BL1a/BL1b, BL3a/BL3b , . . . only those in the region A1 are connected respectively to the sense amplifiers SA1, SA3 , . . . , SAm by the transfer gate transistors Q1a/Q1b, Q3a/Q3b , . . . and are separated from the power source lines VHL.
Then, the word line W1-1 is selected by a line decoder (not shown) and the potential thereof becomes high (see the time point t41 in FIG. 4). The data stored in the memory cell MC connected to the selected word line W1-1 are reflected in each potential difference of the bit line pairs. As only the bit line pairs situated in the region A1 out of the bit line pairs BL1a/BL1b, BL2a/BL2b , . . . and BLma/BLmb are connected to the sense amplifiers SA1, SA3 , . . . and SAm by the transfer gate transistors, the length of the bit lines becomes substantially one half. This makes the potential difference in each bit line pairs twice as much as the prior art as well as makes the charge/discharge of each bit line one half. As those in the region A2 out of said bit line pairs are connected to the power source line VHL, they are maintained at the potential level of VH (see BL1(A1) and BL1(A2) in FIG. 4).
The potential differences in the bit line pairs BL2a/BL2b, BL4a/BL4b , . . . connected to the sense amplifiers SA2, SA4 , . . . in the region B2 reflect the data stored in the memory cells as in the case of the first embodiment (BL2(A1) and BL2(A2) of FIG. 4).
When the control signal φC2 is shifted from a high to low level, the transfer gate transistors Q2a/Q2b, Q4a/Q4b , . . . of the bit line pairs BL2a/BL2b, BL4a/BL4b , . . . are turned OFF. In this state, all the bit lines are divided into the regions A1 and A2 and substantially the same state as in the first embodiment is obtained except that the potentials of the bit lines in the pairs BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb which are in the region A2 are kept at VH. In this manner, a portion of the bit line pairs which is adjacent to the portion of bit line pairs connected to the sense amplifiers can be separated from those sense amplifiers that are connected to said adjacent bit line pairs.
When the sense amplifier activation signals φS1 and φS2 are shifted to a high level (at the time t42 in FIG. 4), all the sense amplifiers are activated to amplify the potential differences from one half of the bit line pairs connected thereto respectively. As the output potential difference of bit line pairs adjacent to each other is not to be amplified by the sense amplifier connected to the other bit line pair adjacent thereto due to the above operation of the transfer gate transistors, crosstalk from the adjacent bit line pairs may be prevented.
After the potential differences of the bit line pairs are fully amplified by sense amplifiers SA1 through SAm, the control signal φC2 reaches a high level while the transfer gate transistors Q2a/Q2b, Q4a/Q4b , . . . are turned ON to thereby amplify the potential difference of the bit line pairs (BL2(A1) and BL2(A2) in FIG. 4). As the control signal φC1 remains at a low level on the other hand, the potential of the portion of the bit line pairs which are in the region A2 of the bit line pairs BL1a/BL1b, BL3a/BL3b , . . . is maintained at VH (BLa(A2) of FIG. 4).
Subsequently, the data of a new level which have been amplified by sense amplifiers are stored in the memory cells MC. Then the potential of the selected word line (in this case the line W1-1) becomes low, the connection between bit lines and the memory cells MC is cut off, and when the sense amplifier activation signals φS1 and φS2 are shifted to a low level, all the sense amplifiers are inactivated. Further, when the precharge signal φP1 and the control signal φC1 become respectively high, the potentials of all the bit lines are shifted to the fixed level of VH.
According to this embodiment, before the potential of the word lines is shifted to a high level in response to the selection thereof, the length of each bit line pairs becomes one half in substance due to the action of the transfer gate transistors as mentioned above, the potential difference at the time of data reading out from the memory cells becomes twice as much as the prior art while the charge/discharge of each bit line pair becomes one half. This reduces the power consumption for the memory cell array as a whole by 25%.
The description of the operations when the word line W1-1 is selected is applicable to the cases where any of the word lines such as W2-1, W2-2 situated in the region A2 is selected by replacing the precharge signal φP1 with φP2, the control signal φC1 with φC2, and the bit line pair BL1 with BL2. Otherwise, the basic operations are identical.
Although description has been made on assumption that the sense amplifier activation signals φS1 and φS2 have the same wave form, they may be different from each other. It is possible to reduce the difference in rising time of a sense amplifier by inputting the signal φS2 first because the potential difference from the bit line pair connected to the sense amplifier which is activated by the signal φS1 is about twice the potential difference from the bit line pair connected to the sense amplifier which is activated by the signal φS2. With this technique, as the time for charge/discharge for amplifying the output from bit line pairs by the sense amplifiers is divided by two, the peak current of the memory cell array may be prevented from increasing.
Referring to FIG. 5, the third embodiment of this invention is identical to the first embodiment except for that the precharge signal φP in the first embodiment is replaced with the signals φP11 and φP12. More particularly, the third embodiment is identical to the first embodiment in construction except that the precharge signal φP11 is to control activation of the precharge transistors QP1a, QP2a, QP3a , . . . which connect one of the bit lines BL1a, BL2a, BL3a , . . . , BLma of the pairs BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb while the precharge signal φP12 is to control the activation of the precharge transistors QP1b, QP2b, QP3b , . . . which connect the other bit lines BL1b, BL2b, BL3b , . . . with the power source line VHL. Therefore, detailed description is omitted.
Referring now to FIG. 6, the case where the word line W1-1 in the region A1 is selected will be described.
As the word line W1-1 is being selected, the precharge signal φP11 which is generated based on the data in the row decoder (not shown) becomes from high to low, and precharge transistors QP1a, QP2a, QP3a , . . . are turned OFF. This separates one of the bit lines BL1a, BL2a, BL3a , . . . , BLma in each pair from the power source line VHL electrically.
When the word line W1-1 is selected, the potential thereof is shifted to a high level. The data stored in the memory cell MC which is connected to the selected word line W1-1 is reflected in the potential in one of the bit lines BL1a, BL2a, BL3a, BLma (at the time 61 in FIG. 6) of each pair.
When the control signal φC is shifted from a high to low level, all the transfer gate transistors Q1a/Q1b, Q2a/Q2b , . . . are turned OFF and all the bit line pairs are divided into the portion in the region A1 and the portion in the region A2.
Then, the sense amplifier activation signal φS is shifted to a high level, and all the sense amplifiers SA1, SA2, SA3 , . . . , SAm are activated to amplify the potential differences of the bit line pairs BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb connected respectively to the sense amplifiers. As the bit line pairs are divided into two groups by the transfer gate transistors Q1a/Q1b, Q2a/Q2b , . . . , the sense amplifiers SA1 through SAm amplify the potential differences from one half of each of the bit line pairs. Out of those portions of bit line pairs which are disconnected from the sense amplifiers, those of one of the bit lines BL1b, BL2b, BL3b , . . . are kept at the power source potential VH. In this state, as the precharge signal φP12 is at a high level, the precharge transistors BL1b, BL2b, BL3b , . . . are activated so that constant potential VH can be supplied through these transistors to the portion of the bit lines BL2b, BL4b in the region A1 and the portion of the bit lines BL1b and BL3b in the region A2 respectively. Therefore, immediately after the sense amplifier activation signal φS is shifted high, one of the bit lines of each pair adjacent to the portion of the bit line pairs connected to the sense amplifiers or bit lines BL1b, BL2b, BL3b , . . . are kept at the constant potential VH to prevent crosstalk.
After the potential differences of the bit line pairs are fully amplified by the sense amplifiers SA1 through SAm, the precharge signal φP12 is shifted to a low level, and all the bit lines are cut off from the power source line VHL, the control signal φC is shifted to a high level and the bit lines BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb which were separated are connected electrically again to amplify the potential differences of all the bit line pairs by the sense amplifiers SA1 through SAm.
The operation thereafter is identical to that described in relation to the first embodiment except that the precharge signals φP11 and φP12 are shifted to a high level at the same timing as that for the precharge signal φP in the first embodiment, and detailed description is omitted.
Referring now to FIG. 7, the fourth embodiment of this invention will be described. While a memory cell array is divided into two or the regions A1 and A2 in the aforementioned first to third embodiments, the memory cell array is divided into three regions of A1, A2 and A3 in this embodiment as each of the bit line pairs is provided with two transfer gates which are used respectively to divide the memory cell array. This embodiment includes transfer gate transistors Q11a, Q11b, Q12a, Q12b, Q13a, Q13b , . . . which divide the memory cell array into the regions of A1 and A3 and transfer gate transistors Q21a, Q21b, Q22a, Q22b, Q23a, Q23b , . . . which divide the memory cell array into the regions of A3 and A2. These transistors are controlled in energization with control signals φC1, φC2, φC3 and φC4 and are supplied with said precharge signals φPC1 through φPC4. Except for the modification, this embodiment is identical to the first embodiment and detailed description for the circuit construction thereof is omitted.
Exemplifying the case where the word line W1-1 in the region A1 is selected, the operation of the embodiment is described below referring to FIG. 8. The precharge signal φP is shifted from a high to low level first and all the bit line pairs BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb are separated from the power source line VHL.
As the word line W1-1 is being selected, the control signal φC1 which is generated based on the data of the line decoder (not shown) is shifted from a high to low level to turn off the transfer gate transistors Q11a/Q11b, Q13a/Q13b , . . . This makes only the portion of the bit line pairs BL1a/BL1b, BL3a/BL3b , . . . which situate in the region A1 or one third of the whole are connected electrically to the sense amplifiers while the rest of them which are in the regions A2 and A3 or two thirds of the whole are cut off from the sense amplifiers.
Subsequently, the word line W1-1 is selected and the potential thereof is shifted to a high level. In this state, the data stored in the memory cell MC connected to the selected word line W1-1 are reflected in potential differences of the bit line pairs respectively, but the potentials of the bit line pairs which have been separated from the sense amplifiers by the transfer gate transistors Q11a/Q11b, Q13a/Q13b , . . . are maintained at VH (BL1(A2, A3) in FIG. 8).
Then, the control signal C4 is shifted to a low level, the transfer gate transistors Q22a/Q22b, Q24a/Q24b , . . . are turned OFF, and one third of the bit line pairs BL2a/BL2b, BL4a/BL4b , . . . or those in the region A2 are connected to the sense amplifiers SA1, SA4 , . . . while the rest of them or two thirds thereof are cut off from the sense amplifiers.
At this time point, the effective length of each of the bit line pairs becomes one third due to the transfer gate transistors Q11a/Q11b, Q13a/Q13b , . . . and Q22a/Q22b, Q24a/Q24b , . . . Then, under this state, the sense amplifier activation signal φS is shifted to high level to activate all the sense amplifiers SA1 through SAm so as to amplify the potential difference from the one third of the bit line pairs of the effective length.
Then, the control signal φC4 is shifted to a high level and the transfer gate transistors Q22a/Q22b, Q24a/Q24b , . . . are turned ON. This makes the output from the bit line pairs in the regions A1 and A3 or the two thirds of the bit line pairs BL2a/BL2b, BL4a/BL4b , . . . to be amplified. The potential of the bit line pairs is shifted by 1/3 Vcc but is returned either to the voltage level. Vcc or GND shortly (BL2(A2, A3) and BL2(A1) in FIG. 8).
As the control signal φC1 remains at a low level, the portion of the bit line pairs BL1a/BL1b, BL3a/BL3b , . . . which are in the regions A2 and A3 are maintained at the potential of VH while the portion in the region A1 is kept at the same potential without change (BL1(A1) and BL1(A2, A3) of FIG. 8).
The operations hereafter are identical to the operations described for the first embodiment in relation to FIG. 2 except that the control signal φC1 rises in synchronization with the fall of the sense amplifier activation signal φS, and detailed description therefor is omitted (in the above operation, the control signals φC2 and φC3 are maintained at a high level).
The above description for this embodiment is applicable to cases where the word lines W2-1 , . . . , W2-n are selected. In that case, the control signal φC1 should be replaced with φC3 and the control signal φC4 with φC2 respectively.
Operation of this embodiment will now be described referring to FIG. 9 for the case where the word line W3-1 in the region A3 is selected. The precharge signal φP is shifted to a low level, and all the bit line pairs BL1a/BL1b, BL2a/BL2b , . . . , BLma/BLmb are cut off from the power source line VHL.
As the word line W3-1 is being selected, the control signals φC2 and φC3 are shifted from a high to low level, and the transfer gate transistors Q12a/Q12b, Q14a/Q14b, Q21a/Q21b, Q23a/Q23b , . . . are turned OFF. Therefore out of the bit line pairs BL1a/BL1b, BL3a/BL3b , . . . , only those in the regions A1 and A3 are connected to the sense amplifiers while out of the bit line pairs BL2a/BL2b, BL4a/BL4b , . . . those within the regions A2 and A3 are connected to the sense amplifiers, and the rest of the bit line pair portions or one third thereof is separated therefrom.
Then, the word line W3-1 is selected and the potential thereof becomes high. The data stored in the memory cell MC connected at the selected word line W3-1 are reflected in the potential difference between the bit line pairs of which the effective length has become two thirds. The potential of the remaining one third of said bit line pairs is kept at the level of VH (see BL1(A2) of FIG. 8).
Then, the sense amplifier activation signal φS is shifted to high level, and all the sense amplifiers SA1 through SAm are activated so that the potential difference from the bit line pairs of which effective length has been reduced to two thirds of the whole is simplified by the sense amplifiers connected thereto.
The operations thereafter are identical to those of the first embodiment which is explained in relation to FIG. 2 except that the control signal φC2 rises simultaneously with the fall of the sense amplifier activation φS, and the detailed description therefor is omitted.
As described in the foregoing statement, this embodiment can prevent crosstalk between adjacent bit line pairs which would otherwise occur immediately after the sense amplifier activation signal is shifted to a high level.
Similarly to the third embodiment, this embodiment can have the same effect as the third embodiment by giving different signals for each of the bit line pairs.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover any modifications or embodiments as fall within the true scope of the invention.
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The semiconductor memory device according to this invention includes a memory cell array which comprises plural memory cells arranged in row and column direction in the form of an array, plural bit line pairs for connecting these memory cells in the unit of a column and word lines for connecting these memory cells in the unit of a row, sense amplifiers which are respectively connected to each of the bit line pairs at one end thereof and which amplify the potential difference between the bit lines of each pair in response to activation signals, and transfer gate means which divide said plural bit lines respectively into at least two portions corresponding to control signals, the sense amplifiers for the bit line pairs which belong to the nth columns (n is an odd numbered integer) thereof being arranged on one end of the bit line pairs and on the other end thereof for the those which belong to the (n+1)th columns. This construction of the device can prevent crosstalk which would otherwise caused between adjacent bit line pairs immediately after the sense amplifiers are activated.
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FIELD OF THE PRESENT INVENTION
[0001] The present invention relates to semiconductors, and more particularly, to a Liquid Crystal on Silicon (LCOS) display unit and a method for forming the same.
BACKGROUND OF THE PRESENT INVENTION
[0002] In recent years, many new technologies related to Liquid Crystal Displays (LCD) have come forth, and among others, Liquid Crystal on Silicon (LCOS) is a hot technology. LCOS relates to a new reflective micro LCD projection technology. To form an LCOS structure, transistors are grown on a silicon substrate; a drive panel (also referred to as Complementary Metal-Oxide-Semiconductor-LCD (CMOS-LCD)) is fabricated using a semiconductor process; the transistors are flattened by polishing technology and plated with aluminum to act as micro mirrors; thus a Complementary Metal-Oxide-Semiconductor (CMOS) substrate is formed; then the CMOS substrate is jointed with an upper glass substrate having transparent electrodes, and liquid crystal is injected into the structure. An encapsulation test is then performed.
[0003] Compared with conventional LCD and Digital Light Processing (DLP) technologies, LCOS has the following technical advantages: a) high light utilization efficiency: LCOS is similar to LCD technology, and mainly different from LCD in that LCOS is a reflective imaging system, such that the light utilization efficiency may reach 40% or more which is equivalent to the light utilization efficiency of DLP, while the light utilization efficiency of transmissive LCD only reaches about 3%; b) small volume: LCOS may integrate periphery circuits such as driver ICs to a CMOS substrate completely, so as to reduce the number of periphery ICs and the encapsulation cost, and decrease the whole volume; c) high resolution: since the transistor and the driver circuits of an LCOS are both fabricated in a silicon substrate and located under the reflective surface, they don't occupy surface area, and only pixel gaps occupy opening area, while Thin Film Transistors (TFTs) and wires of a transmissive LCD both occupy the opening area, so that both the resolution and the opening ratio of LCOS are higher than those of transmissive LCD; d) more mature manufacturing technology: the manufacturing of LCOS may be divided into Front of Line (FL) semiconductor CMOS manufacturing and End of Line (EL) liquid crystal panel jointing and encapsulating. There have been mature designing, simulating, fabricating and testing technologies for the FL semiconductor CMOS manufacturing, and now the product yield has reached above 90% with a very low cost; as for the EL liquid crystal panel jointing and encapsulating, although the yield is only 30% at now, since the manufacturing of liquid crystal panel has been developed rather maturely, the yield may be increased more rapidly than that of digital micromirror device (DMD) in theory. As a result, LCOS has more chances to be the mainstream technology than DLP. Therefore, LCOS technology has a bigger potential in application markets of digital camera, digital video camera, projector, monitor, large size TV and mobile telephone.
[0004] In LCOS technology, each pixel switch circuit consists of a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) and a capacitor. In conventional processes, the capacitor occupies half of the whole pixel area. As the circuit area decreases, the capacitor area also decreases. This will increase refresh rate in practical use. In order to increase capacitance, U.S. Pat. No. 6,437,839 discloses an LCOS pixel with multiple capacitors, the structure of which is shown in FIG. 1 , and formed by the following steps: a diffusion region is formed on a substrate 40 as a top electrode of a first capacitor; an oxide layer is formed on the diffusion region as a dielectric layer 22 b of the first capacitor; a first polysilicon layer 26 is formed on the dielectric layer 22 b as a common electrode of two capacitors; a second oxide layer is formed on the first polysilicon layer 26 as a dielectric layer 24 b of a second capacitor; a second polysilicon layer is formed on the second oxide layer as a top electrode 24 a of the second capacitor; an insulation layer 42 is formed on the above structure; and an interconnection structure and an micromirror layer is formed on the above structure. As shown in FIG. 1 , the capacitance is increased in the improved structure, but the processes are also increased, resulting in increased processing cost.
[0005] At present, each micromirror on the substrate surface serves as a display pixel, and each display pixel has a switch circuit. A pixel switch (MOSFET) and a capacitor must be designed in the area of a pixel. In order to lower the display refresh rate, the capacitance needs to be as large as possible. However, as restricted by the pixel area, if the capacitor occupies the pixel area in too high proportion, the performance of the switch circuit may be affected inevitably. For example, since the design area of the MOSFET is decreased, the insulation performance of the MOSFET may be affected and current leakage may occur.
SUMMARY OF THE PRESENT INVENTION
[0006] The present invention aims to solve the following problems: as higher and higher resolution is required for a display, the area of each pixel is becoming smaller and smaller; as restricted by the pixel area, it is difficult to obtain a pixel switch circuit with high performance and hold a high capacitor voltage level at the same time.
[0007] In an aspect of the present invention, there is provided a Liquid Crystal on Silicon (LCOS) display unit, which includes: a silicon substrate; a pixel switch circuit layer on the silicon substrate, the pixel switch circuit layer including a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET); a light shielding layer on the pixel switch circuit layer; an insulation layer on the light shielding layer; a micromirror layer on the insulation layer, the micromirror layer, the insulation layer and the light shielding layer constituting a capacitor, and the micromirror layer being electrically connected with a source of the MOSFET, wherein the light shielding layer is grounded.
[0008] Optionally, a mirror connecting pad is formed in the light shielding layer to be isolated from the light shielding layer; and the mirror connecting pad is electrically connected with the source of the MOSFET.
[0009] Optionally, an opening is formed in the insulation layer; and the opening is filled with a conductive material which electrically connects the micromirror layer to the mirror connecting pad.
[0010] Optionally, the light shielding layer is electrically connected with a ground pad via a through hole of the pixel switch circuit layer; and the ground pad is grounded.
[0011] Optionally, the insulation layer has a thickness ranging from 100 Å to 1000 Å.
[0012] Optionally, the insulation layer is made of silicon oxide, silicon nitride, silicon oxynitride, hafnium oxide, aluminum oxide, zirconium oxide or a combination thereof.
[0013] Optionally, the micromirror layer is made of aluminum.
[0014] Optionally the light shielding layer is made of metallic titanium, titanium nitride, AlCu alloy, titanium nitride or a combination thereof.
[0015] In another aspect of the present invention, there is provided a method for forming a Liquid Crystal on Silicon (LCOS) display unit, which includes: forming a pixel switch circuit layer on a silicon substrate, the pixel switch circuit layer including a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET); forming a light shielding layer on the pixel switch circuit layer; forming an insulation layer on the light shielding layer; forming a micromirror layer on the insulation layer; the micromirror layer, the insulation layer and the light shielding layer constituting a capacitor, and the micromirror layer being electrically connected with a source of the MOSFET, wherein the light shielding layer is grounded.
[0016] Optionally, the method further includes forming in the light shielding layer a mirror connecting pad to be isolated from the light shielding layer, wherein the mirror connecting pad is electrically connected with the source of the MOSFET.
[0017] Optionally, the method further includes forming an opening in the insulation layer and filling the opening with a conductive material, wherein the conductive material electrically connects the micromirror layer to the mirror connecting pad.
[0018] Optionally, the light shielding layer is electrically connected to a ground pad via a through hole in the pixel switch circuit layer; and the ground pad is grounded.
[0019] Optionally, the insulation layer has a thickness ranging from 100 Å to 1000 Å.
[0020] Optionally, the insulation layer is made of silicon oxide, silicon nitride, silicon oxynitride, hafnium oxide, aluminum oxide, zirconium oxide or a combination thereof.
[0021] Optionally, the micromirror layer is made of aluminum.
[0022] Optionally, the light shielding layer is made of metallic titanium, titanium nitride, AlCu alloy, titanium nitride or a combination thereof.
[0023] Compared with the prior art, the present invention has the following advantages: a Metal-Insulator-Metal (MIM) capacitor consisting of a micromirror layer, a insulation layer and a light shielding layer is formed by grounding the light shielding layer on a pixel switch circuit layer. Therefore the pixel switch circuit and the capacitor are in vertical distribution, that is, the switch circuit and the capacitor both have an allowable design area of the size of one pixel. Thus, the present invention makes full use of the area of the whole pixel, increases the capacitance and decreases the refresh rate of the LCOS display unit.
[0024] Additionally, the present invention also increases the design area of a switch circuit, and switch circuits with high performance may be designed according to different requirements, so that design flexibility of switch circuits may be increased.
[0025] The present invention also simplifies the procedure for manufacturing capacitors, thus decreasing the overall chip manufacturing cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic diagram illustrating the structure of a capacitor of a LCOS display unit in prior art;
[0027] FIGS. 2A to 2K are schematic diagrams illustrating a method for forming an LCOS display unit according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0028] The above objects and advantages of the present invention will become more apparent with reference to the following description of the preferred embodiments given in conjunction with the accompanying drawings.
[0029] A method for forming a Liquid Crystal on Silicon (LCOS) display unit is now described, which includes: forming a pixel switch circuit layer on a silicon substrate, the pixel switch circuit layer including a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET); forming a light shielding layer on the pixel switch circuit layer; forming an insulation layer on the light shielding layer; forming a micromirror layer on the insulation layer; wherein the micromirror layer, the insulation layer and the light shielding layer constitute a capacitor, the micromirror layer is electrically connected with a source of the MOSFET, and the light shielding layer is grounded.
[0030] FIGS. 2A to 2J illustrating a method for forming an LCOS display unit according to an embodiment of the present invention. The embodiments of the present invention will be described hereunder in detail in conjunction with the drawings.
[0031] Referring to FIG. 2A , first, a pixel switch circuit layer 22 including a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is formed on a silicon substrate 21 . The technology for forming the pixel switch circuit layer 22 is known to those skilled in the art. In a preferred embodiment of the present invention, the pixel switch circuit layer 22 includes an interlayer insulation layer 201 , and ground pads 202 , a signal pad 203 , a connection pad 204 which are inserted in the interlayer insulation layer 201 , as well as connection through holes. The ground pads 202 are connected to ground, the signal pad 203 is adapted to apply a voltage to the MOSFET of a drive circuit, the signal pad 203 is connected with a drain of the MOSFET of the pixel switch circuit layer 22 via a through hole, and a source of the MOSFET is electrically connected with the connection pad 204 via a through hole.
[0032] Then, a first conductive layer 205 is formed on the interlayer insulation layer 202 . The first conductive layer 205 is made of single or multiple layers of conductive materials. In a preferred embodiment of the present invention, the first conductive layer 205 is a multi-layer structure consisting successively of metallic titanium, titanium nitride, AlCu alloy, titanium nitride and metallic titanium. Preferably, the first conductive layer 205 has a thickness ranging from 1000 Å to 6000 Å.
[0033] Referring to FIG. 2B , an island-like mirror connecting pad 206 and a light shielding layer 205 a are formed in the first conductive layer 205 by the existing photolithography and etching technologies. The purpose for forming the light shielding layer 205 a is to prevent the light from leaking onto the circuit devices in the silicon substrate. In case that the light leaks onto the circuit devices, it will affect the performance and life of the circuit, and thus a specific layer of metal is required to shield light. Gaps 206 a between the mirror connecting pad 206 and the light shielding layer 205 a insulatively isolate the mirror connecting pad 206 from the light shielding layer 205 a . The mirror connecting pad 206 is electrically connected with the source of the MOSFET of the pixel switch circuit layer via the connection pad 204 and a through hole. The light shielding layer 205 a is electrically connected with ground pads 202 via through holes in the pixel switch circuit layer 22 . The ground pads 202 are grounded.
[0034] Referring to FIG. 2C , a silicon oxide layer 207 is form on the light shielding layer 205 a and the mirror connecting pad 206 as well as in the gaps 206 a by a high-density plasma chemical vapor deposition (CVD). Since the gaps 206 a are filled, grooves are generated on the surface of the silicon oxide layer 207 toward the gaps 206 a . The silicon oxide layer 207 formed has a thickness ranging from 200 nm to 1000 nm.
[0035] Referring to FIG. 2D , an organic Bottom Anti-Reflecting Layer (BARC) 208 is formed on the surface of the silicon oxide layer 207 . The organic bottom anti-reflecting layer 208 has a good flowability and fills up the grooves on the surface of the oxide layer 207 completely. The purpose for forming the organic bottom anti-reflecting layer 208 is to fill the grooves on the surface of the silicon oxide layer 207 so as to protect the part of the silicon oxide towards the grooves and keep the surface flat after etching.
[0036] Referring to FIG. 2E , the organic bottom anti-reflecting layer 208 is removed. After the removing, the residual organic bottom anti-reflecting layer 208 a fills up the grooves on the surface of the silicon oxide layer 207 . The method for partially removing the organic bottom anti-reflecting layer 208 is well known to those skilled in the art. In a preferred embodiment of the present invention, O 2 plasma is employed to etch the organic bottom anti-reflecting layer 208 , such that part of the organic bottom anti-reflecting layer 208 reacts with the O 2 plasma and generates gases such as CO 2 and H 2 O, which escape from the surface of the silicon substrate.
[0037] Referring to FIG. 2F , the silicon oxide layer 207 is removed. There is a residual silicon oxide layer 207 a on the surfaces of the light shielding layer 205 a and the mirror connecting pad 206 as well as in the gaps 206 a . The technology for removing the silicon oxide layer 207 is well known to those skilled in the art. In a preferred embodiment of the present invention, dry etching is employed to etch the silicon oxide layer 207 . After the silicon oxide layer 207 is removed, due to the inherent defect of the dry etching, bumps may be formed on the surface of the residual silicon oxide layer 207 a at the gaps 206 a . These bumps will cause unevenness of the finally generated micromirror which is covered with liquid crystal. If the surface of the micromirror is uneven, the liquid crystal orientation and the electric field applied to the liquid crystal will be affected, so that the display performance will be affected.
[0038] Referring to FIG. 2G , the surface of the residual silicon oxide layer 207 a is planarized. During the planarization process, the residual silicon oxide layer 207 a on the light shielding layer 205 a is removed until the light shielding layer 205 a is exposed. Thereafter, a smooth surface consisting of the light shielding layer 205 a , the mirror connecting pad 206 , and the silicon oxide 207 b filled in the gaps 206 a is formed. The technology for planarizing the surface of the residual silicon oxide layer 207 a is well known to those skilled in the art. In a preferred embodiment of the present invention, the surfaces of the residual silicon oxide layer 207 a and the light shielding layer 205 a are polished simultaneously by a Chemical-Mechanical Polishing (CMP) device. Finally, a smooth, flat surface is formed.
[0039] Referring to FIG. 2H , an insulation layer 209 is formed on the surfaces of the light shielding layer 205 a , the mirror connecting pad 206 and the silicon oxide 207 b filled in the gaps 206 a . The insulation layer 209 may be made of silicon oxide, silicon nitride, silicon oxynitride or a combination thereof, and the insulation layer 209 may also be made of high-k dielectrics such as hafnium oxide, aluminum oxide, zirconium oxide and so on. In a preferred embodiment of the present invention, a three-layer ONO structure made of silicon oxide, silicon nitride and silicon oxide is used to serve as an insulation layer 209 , and the insulation layer 209 has a thickness ranging from 100 Å to 1000 Å. The method for forming the insulation layer 209 is well known to those skilled in the art.
[0040] Referring to FIG. 2I , an opening 210 is formed on the insulation layer 209 . The opening 210 exposes the mirror connecting pad 206 . The method for forming the opening 210 is well known to those skilled in the art.
[0041] Referring to FIG. 2J , a metal layer 211 is formed on the insulation layer 209 a and in the opening 210 . The metallic material filled in the opening electrically connects the metal layer 211 with the mirror connecting pad 206 . A metallic material with a high reflectivity which may be aluminum, silver or an alloy thereof is employed to form the metal layer 211 . In a preferred embodiment of the present invention, the metal layer 211 is formed by using metallic aluminum. The metal layer 211 has a thickness ranging from 1000 Å to 6000 Å. Due to the existence of the opening, after the metal layer 211 is formed, a groove is formed on the surface of the metal layer 211 toward the opening 210 , and the depth range of the groove is 100 Å to 200 Å.
[0042] Referring to FIG. 2K , the metal layer 211 is planarized to form a micromirror layer 211 a . The technology for planarizing the metal layer 211 is well known to those skilled in the art. In a preferred embodiment of the present invention, a Chemical-Mechanical Polishing (CMP) device is employed to planarize the surface of the metal layer 211 , finally forming a smooth, flat micromirror layer 211 a . The micromirror layer 211 a has a thickness ranging from 800 Å to 5800 Å. The micromirror layer 211 a is electrically connected with the mirror connecting pad 206 via the metal filled in the opening 210 , so that the micromirror layer 211 a is connected to the source of the MOSFET of the pixel switch circuit layer 22 .
[0043] In an embodiment of the present invention, a structure of an LCOS display unit obtained based on the implementing of the above process is shown in FIG. 2K . The structure includes: a pixel switch circuit layer 22 formed on a silicon substrate 21 , the pixel switch circuit layer 22 including a Metal-Oxide-Semiconductor field-effect transistor (MOSFET); a light shielding layer 205 a on the pixel switch circuit layer 22 ; an insulation layer 209 a on the light shielding layer 205 a ; a micromirror layer 211 a on the insulation layer 209 a . The micromirror layer 211 a , the insulation layer 209 a and the light shielding layer 205 a constitute a capacitor, in which the micromirror layer 211 a is electrically connected with a source of the MOSFET, and the light shielding layer 205 a is grounded.
[0044] An island-like mirror connecting pad 206 insulated from the light shielding layer 205 a is formed in the center of the light shielding layer 205 a . The light shielding layer 205 a is electrically connected with ground pads 202 in the pixel switch circuit layer 22 , and the ground pads 202 are grounded; the mirror connecting pad 206 is electrically connected with a source of the MOSFET via a connection pad 204 formed in the pixel switch circuit layer 22 ; an opening 210 is formed in the insulation layer 209 a , and the micromirror layer 211 a is electrically connected with the mirror connecting pad 206 via a metallic material filled in the opening 210 which is the same as that of the micromirror layer 211 a . The insulation layer 209 a has a thickness ranging from 100 Å to 1000 Å.
[0045] As shown in FIG. 2K , the micromirror layer 211 a , the insulation layer 209 a and the light shielding layer 205 a constitute a metal-insulator-metal (MIM) capacitor. The upper electrode (mirror 211 a ) of the capacitor is electrically connected with the source of the MOSFET, and the lower electrode (light shielding layer 205 a ) of the capacitor is electrically connected with the ground pads 202 . Thus, the MOSFET and the capacitor constitute a dynamic random access memory (DRAM). When a voltage is applied on a gate of the MOSFET of the pixel switch circuit layer 22 , the MOSFET is turned on, and since the upper electrode of the capacitor is electrically connected with the source of the MOSFET, the capacitor is charged via the voltage applied on the signal pad 203 . The capacitor area is the area of the whole pixel, moreover the insulation layer 209 a is thin thus the capacitance of the capacitor is increased, such that the refresh rate is decreased. The insulation layer 209 a is thin, so the formed thickness of the opening 210 is small, and the contact resistance between the micromirror layer 211 a and the mirror connecting pad 206 is decreased. At last, since the insulation layer 209 a is thin, the probability of a light entering onto the silicon devices through diffuse reflection is reduce, and accordingly the light shielding is enhanced.
[0046] Additionally, according to the embodiments of the present invention, the design area of a switch circuit is also increased, and switch circuits with high performance may be designed according to different requirements, so that design flexibility of switch circuits may be increased. F or example, a switch with a N-type Metal-Oxide-Semiconductor (NMOS) and a P-type Metal-Oxide-Semiconductor (PMOS) in parallel may be designed to improve the display gamma; or a NMOS may be designed to increase the width of the device so as to improve display reaction speed.
[0047] The present invention is described above in, but not limited to, the preferred embodiments. It is noted that those skilled in the art may make modifications and variations, without departing from the basic principle of the present invention; any of those modifications and variations shall fall into the protected scope of the present invention defined by the following claims.
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An embodiment of the present invention discloses a Liquid Crystal on Silicon (LCOS) display unit, in which a Metal-Insulator-Metal (MIM) capacitor consisting of a micromirror layer, a insulation layer and a light shielding layer is formed by grounding the light shielding layer on a pixel switch circuit layer. Therefore the pixel switch circuit and the capacitor are in vertical distribution, that is, the switch circuit and the capacitor both have an allowable design area of the size of one pixel. Another embodiment of the present invention provides a method for forming a Liquid Crystal on Silicon (LCOS) display unit.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to roller skates, and in particular, relates to self propelled roller skates requiring no additional energy from the user thereof other than the shifting of his own body weight and alternately raising the front portion of his foot small amounts.
2. Description of the Relevant Art
Various types of roller skates are known in the art, all of which have been suggested by inventors for use by individuals to help them engage in more rapid movement along a flat surface while expending relatively small amounts of energy. Typical of these roller skates is U.S. Pat. No. 3,112,119 issued to C. M. Sweet on Nov. 26, 1963. The device disclosed therein utilizes an articulated frame mechanism with a plurality of wheels on the front portion of the skate and a braking portion provided by the heel portion. The user of the skates can adjust his weight to accomplish braking, by leaning backwardly (putting the weight on the shoe heels) or by leaning in a forwardly direction, the weight is placed on the rotating wheels thereby providing movement over a flat surface. However, with this type of device, it is necessary that the wearer of the roller skate use large amounts of energy to obtain movement through a movement commonly referred to as "pumping" wherein one foot of the individual is used to push while the weight of the body is placed on the wheel portion of the skate. This pumping action is repeated alternately between feet, obtaining locomotion on a flat surface. Relatively large amounts of energy are required to obtain movement.
Another type of roller or shoe skate is disclosed in U.S. Pat. No. 3,983,643 issued to W. Schreyer et al on Oct. 5, 1976. The apparatus disclosed therein relates to a shoe which may be utilized for walking or roller skating wherein the roller skating apparatus is contained within the sole of the shoe and may be used for either walking or roller skating. Hereagain, once the roller skating mode is selected, the pumping action is required to get locomotion along a flat surface.
Therefore, it is an object of the present invention to overcome the shortcomings known in the prior art by providing a simple roller skating mechanism which can obtain locomotion by merely shifting the wearer's weight from the front portion of one foot to the rear portion of the same foot or from one foot to the other without expending additional energy in a pumping motion.
It is another object of the present invention to provide a reliable and simple roller skate that may be utilized by young as well as old persons for locomotion since minimal amounts of energy are required.
It is still another object of the present invention to provide a roller skate which achieves locomotion without requiring pumping by the individual wearing them.
It is still another object of the present invention to provide a roller skate which can provide a braking mode so that a more stable and secure operation is obtained.
It is yet another object of the present invention to provide a roller skate which may be worn by an individual without the fear of falling because of a lack of means to stop the skate.
The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawing which forms a part hereof, and in which there is shown, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.
SUMMARY OF THE INVENTION
A self-propelled roller skate according to the principles of the present invention, used for affixment to an individual's shoe comprises as articulated frame having a front portion and a rear portion. The front and rear portions are coupled together by a hinge for providing in the vertical plane therebetween. The front portion includes; a forward toe portion adapted to receive and cooperate with the toe of a shoe removably retaining the shoe toe therein; wheel means affixed to the underside of the forward toe portion; a ratchet rack vertically disposed on the underside of the frame front portion; and a pair of wheels disposed on the distal ends of an axle, the axle has a ratchet gear thereon, and the wheels and axle are spring mounted to the underside of the frame front portion for vertical movement with the ratchet gear in cooperating contact with the teeth of the ratchet rack. The rear portion includes; a heel portion adapted to receive the heel of an individual's shoe; retaining means disposed in the heel portion for removably clamping the heel of the shoe and retaining it therein; and braking material disposed on the underside of the heel portion for coming into contact with the surface upon which the skate is used to provide braking.
A self-propelled roller skate for affixment to an individuals shoe, according to the principles of the present invention comprises an articulated frame having a front portion and a rear portion. The front and rear portions are coupled by a hinge for providing movement in a vertical plane therebetween. The front portion includes a forward toe portion adapted to receive and cooperate with the toe portion of a shoe, removably retaining the shoe toe therein and a pair of wheels affixed to the underside of the toe portion, a ratchet rack is vertically disposed on the underside of the frame front portion. A pair of wheels are disposed on the distal ends of an axle with the axle having a ratchet gear disposed thereon. The wheels and the axle are spring mounted to the underside of the frame front portion for vertical movement. The ratchet gear is disposed in cooperating contact with the teeth of the ratchet rack. The rear portion includes a heel portion adapted to receive the heel of an individual's shoe. Retaining means disposed in the heel portion is provided for removably clamping the shoe heel and holding it therein. A braking material is disposed on the underside of the heel portion for contact with the surface upon which the skate is used in order to provide braking. The subject matter which I regard as my invention is particularly pointed out and distinctly claimed in the concluding portion of the Specification. The invention, itself, however both to organization and the method of operation, together with further obvious advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing wherein like reference characters refer to like elements.
BRIEF DESCRIPTION OF THE DRAWING
In order that the invention may be more fully understood, it will now be described, by way of example, with reference to the accompanying drawing, in which:
FIG. 1 is a pictorial representation of a self-propelled roller skate affixed to an individual's shoe, according to the principles of the present invention;
FIG. 2 is an enlarged partial view in elevation of a portion of the embodiment shown in FIG. 1;
FIG. 3 is an enlarged partial view of another portion of the embodiment disclosed in FIG. 1;
FIG. 4 is a cross-sectional view of the embodiment disclosed in FIG. 2 taken along the line 4--4;
FIG. 5 is a pictorial representation of another embodiment of a self-propelled roller skate, according to the principles of the present invention, having an individual's shoe affixed thereon;
FIG. 6 is a bottom view of the embodiment disclosed in FIG. 5;
FIG. 7 is an enlarged isometric representation of a portion of the embodiment disclosed in FIGS. 5 and 6; and
FIG. 8 is an enlarged view in elevation taken along the line 8--8 of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the figures, and in particular to FIG. 1, there is shown a self-propelled roller skate 10 affixed to the underside of a shoe 12 worn by an individual 14 desirous of obtaining mobility with a minimum of effort. The roller skate 10 includes an articulated frame 16, having a front portion 18 and a rear portion 20 coupled together by a hinge 22 thereby permitting the rear portion 20 to move relative to the front portion in the direction of arrows 24 and 26 as will be explained hereinafter.
The front portion 18 includes a forward toe portion 28 which is curved and adapted to receive the toe portion 30 of a shoe worn by an individual. The underside of the frame 16 is preferably provided with a pair of wheels 32 and 34, provided on an axle 36, affixed to the underside 38 of the front portion 18 of the skate frame 16, and are freely rotatable when in contact with a surface 40 upon which said skate is utilized.
Affixed to the underside 38 of the front portion 18 is a pair of vertically disposed frame members 42 and 44, which are spaced apart with the frame member 44 being more rearward and positioned proximate the hinge 22 provided on the rear distal end of the front portion 18. Frame members 42 and 44 are provided with oppositely disposed channel guides 46 and 48 which are adapted to cooperate with channels 50 and 52 provided in upper and lower disk members 54 and 56 (see FIG. 4). Upper disk member 54 is provided with a centrally disposed aperture 58 through which a threaded shaft 60 may be received. Shaft 60 is affixed to the underside 38 of frame 16 in a conventional manner with a threaded nut 62 disposed therebetween. Movement of nut 62 along the threaded shaft 60 permits the position, in the vertical direction, of upper disk 54 to be moved in a vertical direction, the reason for which will be disclosed shortly. A coil spring 64 surrounds threaded shaft 60 and is disposed between upper disk member 54 and lower disk member 56. Movement of nut 62 therefore, can adjust tension appearing on coil spring 64.
The lower disk member 56 is provided with a rotatably mounted axle 66 on the underside thereof. Preferably, the axle is housed in ball bearings and is disposed transverse to the longitudinal axis of the front portion 18 of the frame 16. The distal ends of axle 66 are provided with a pair of wheels 68 and 70 rigidly affixed thereon. Disposed upon axle 66 and displaced from the coil spring 64 is a ratchet gear 72 having teeth 74 formed from the axle 66 (see FIG. 4).
An L-shaped bracket 76 is affixed to the underside 38 of the front portion 18 of frame 16 by means of rivets 78 and 80 and includes a pivot pin 82 which retains a vertically disposed ratchet rack 84 having an aperture 86 provided on one distal end. The ratchet rack 84 is freely movable about pivot pin 82 and is urged in a rearward direction by a coil spring 88 disposed between the vertical portion of the L-shaped bracket 76 and the vertically disposed ratchet rack 84 urging it in a rearwardly direction so that the teeth 90 provided thereon may come into contact and cooperate with the teeth 74 provided on the ratchet gear 72. The teeth 90 provided on the ratchet rack 84 will cause the axle 66 to rotate in the direction of arrow 92 whenever axle 66 is permitted to move in an upwardly or vertical direction as shown by arrow 94. Thus, movement of axle 66 in an upwardly direction (arrow 94) while movement of the ratchet rack 84 in a downwardly direction (arrow 96) will cause rotation of axle 66 in the direction of arrow 92. Coil spring 64 normally urges axle 66 in a downwardly direction (arrow 98) thus causing the axle to move to the distal or extreme end of the ratchet rack 84.
The rear portion 20 of frame 16 includes a heel portion 100 adapted to receive the heel portion 102 of an individual's shoe. An upwardly extending bracket 104 may include a threaded screw 106 which may be tightened to retain the heel portion 102 of the individual's shoe in position during use of the self-propelled roller skate 10. Conventionally affixed on the underside 108 of heel portion 100 is a braking material 110, which may be fabricated from rubber, asbestos, or any other material which may be suitable for braking on the surface upon which the skate is to be used.
In operation, a skate 10 is placed on each foot of the user. By either raising one foot or the other, spring 64 will urge axle 66 in a downward direction thereby moving axle 66 to the distal end of ratchet rack 84. This may be accomplished by either raising one's foot slightly or by shifting the individual's weight to the rear portion 20 of the frame 16 resting on the braking material 110 and thus raising the front portion 18 of the frame out of contact with the surface 40 upon which the skate is to be used. By repeatedly shifting the weight of the individual alternately between one foot and the other, or from one heel to one toe and then to the other foot in the same manner, the axle 66 is moved to its initial or starting position each time. By stepping down on the front portion 18 of the frame 16, the axle and wheels together therewith are urged in an upwardly direction (direction of arrow 94) and caused to rotate by the teeth 90 of ratchet rack 84 cooperating with the teeth 74 of ratchet gear 72 cooperating therewith, thereby providing rotary motion in the direction of arrow 92 of the wheels 68 and 70 propelling an individual in a forward direction along the surface. The gait utilized by the individual can be either what is known as a waddling motion, moving from side to side, or a heel-toe motion. Both movements will propel an individual along the surface with a minimum of energy being expended, utilizing only the individual's weight to provide the energy for propulsion.
Referring now to FIG. 5 in which there is shown an alternative embodiment of the subject invention wherein like referenced characters refer to like elements. The self-propelled rollerskate 112 disclosed in FIG. 5 includes an articulated frame 16 having a front portion 18 and a rear portion 20 similar to that disclosed in FIG. 1, including a front wheel axle 36 and wheels 32 and 34 affixed to the underside 38 of the front portion 18 by means of a support bracket 114 in a conventional manner. Wheels 32 and 34 are permitted to freely rotate as disclosed earlier. The rear portion 20 of frame 16 is hingedly affixed to the front portion 18 by means of a hinge 22, thus permitting the rear portion 20 to move in a generally vertical direction as shown by arrows 24 and 26. A bracket 104 is provided on the heel portion 100 and contains an adjustment screw 106 adapted to retain an individual's shoe 12 in the same manner as disclosed in the earlier embodiment. The toe portion of shoe 12 is retained in the front portion 18 of frame 16 similarly.
FIG. 6 is a view of the underside of the frame 16 and discloses the location of the driving mechanism for the alternative embodiment of the self-propelled roller skate 12, wherein the driving mechanism is disposed in the central, generally horizontal section 114 of the front portion 18 of the articulated frame 16. The hinge 22 connecting the front portion 18 to the rear portion 20 includes a leaf spring member 116 having one end affixed to the front portion 18 and retained by a detent 118 to insure that the rear portion 20 is urged in an upwardly direction until the weight of an individual is moved to the heel portion of his shoe. The remaining features of the heel portion 100 are identical to the construction described with the first embodiment.
Referring now to the figures, and in particular to FIG. 1, there is shown a self-propelled roller skate 10 affixed to the underside of a shoe 12 worn by an individual 14 desirous of obtaining mobility with a minimum of effort. The roller skate 10 includes an articulated frame 16, having a front portion 18 and a rear portion 20 coupled together by a hinge 22 thereby permitting the rear portion 20 to move relative to the front portion in the direction of arrows 24 and 26 as will be explained hereinafter.
The front portion 18 includes a forward toe portion 28 which is curved and adapted to receive the toe portion 30 of a shoe worn by an individual. The underside of the frame 16 is preferably provided with a pair of wheels 32 and 34, provided on an axle 36, affixed to the underside 38 of the front portion 18 of the skate frame 16, and are freely rotatable when in contact with a surface 40 upon which said skate is utilized.
Affixed to the underside 38 of the front portion 18 is a pair of vertically disposed frame members 42 and 44, which are spaced apart with the frame member 44 being more rearward and positioned proximate the hinge 22 provided on the rear distal end of the front portion 18. Frame members 42 and 44 are provided with oppositely disposed channel guides 46 and 48 which are adapted to cooperate with channels 50 and 52 provided in upper and lower disk members 54 and 56 (see FIG. 4). Upper disk member 54 is provided with a centrally disposed aperture 58 through which a threaded shaft 60 may be received. Shaft 60 is affixed to the underside 38 of frame 16 in a conventional manner with a threaded nut 62 disposed therebetween. Movement of nut 62 along the threaded shaft 60 permits the position, in the vertical direction, of upper disk 54 to be moved in a vertical direction, the reason for which will be disclosed shortly. A coil spring 64 surrounds threaded shaft 60 and is disposed between upper disk member 54 and lower disk member 56. Movement of nut 62 therefore, can adjust tension appearing on coil spring 64.
The lower disk member 56 is provided with a rotatably mounted axle 66 on the underside thereof. Preferably, the axle is housed in ball bearings and is disposed transverse to the longitudinal axis of the front portion 18 of the frame 16. The distal ends of axle 66 are provided with a pair of wheels 68 and 70 rigidly affixed thereon. Disposed upon axle 66 and displaced from the coil spring 64 is a ratchet gear 72 having teeth 74 formed from the axle 66 (see FIG. 4).
An L-shaped bracket 76 is affixed to the underside 38 of the front portion 18 of frame 16 by means of rivets 78 and 80 and includes a pivot pin 82 which retains a vertically disposed ratchet rack 84 having an aperture 86 provided on one distal end. The ratchet rack 84 is freely movable about pivot pin 82 and is urged in a rearward direction by a coil spring 88 disposed between the vertical portion of the L-shaped bracket 76 and the vertically disposed ratchet rack 84 urging it in a rearwardly direction so that the teeth 90 provided thereon may come into contact and cooperate with the teeth 74 provided on the ratchet gear 72. The teeth 90 provided on the ratchet rack 84 will cause the axle 66 to rotate in the direction of arrow 92 whenever axle 66 is permitted to move in an upwardly or vertical direction as shown by arrow 94. Thus, movement of axle 66 in an upwardly direction (arrow 94) while movement of the ratchet rack 84 in a downwardly direction (arrow 96) will cause rotation of axle 66 in the direction of arrow 92. Coil spring 64 normally urges axle 66 in a downwardly direction (arrow 98) thus causing the axle to move to the distal or extreme end of the ratchet rack 84.
The rear portion 20 of frame 16 includes a heel portion 100 adapted to receive the heel portion 102 of an individual's shoe. An upwardly extending bracket 104 may include a threaded screw 106 which may be tightened to retain the heel portion 102 of the individual's shoe in position during use of the self-propelled roller skate 10. Conventionally affixed on the underside 108 of heel portion 100 is a braking material 110, which may be fabricated from rubber, asbestos, or any other material which may be suitable for braking on the surface upon which the skate is to be used.
In operation, a skate 10 is placed on each foot of the user. By either raising one foot or the other, spring 64 will urge axle 66 in a downward direction thereby moving axle 66 to the distal end of ratchet rack 84. This may be accomplished by either raising one's foot slightly or by shifting the individual's weight to the rear portion 20 of the frame 16 resting on the braking material 110 and thus raising the front portion 18 of the frame out of contact with the surface 40 upon which the skate is to be used. By repeatedly shifting the weight of the individual alternately between one foot and the other, or from one heel to one toe and then to the other foot in the same manner, the axle 66 is moved to its initial or starting position each time. By stepping down on the front portion 18 of the frame 16, the axle and wheels together therewith are urged in an upwardly direction (direction of arrow 94) and caused to rotate by the teeth 90 of ratchet rack 84 cooperating with the teeth 74 of ratchet gear 72 cooperating therewith, thereby providing rotary motion in the direction of arrow 92 of the wheels 68 and 70 propelling an individual in a forward direction along the surface. The gait utilized by the individual can be either what is known as a waddling motion, moving from side to side, or a heel-toe motion. Both movements will propel an individual along the surface with a minimum of energy being expended, utilizing only the individual's weight to provide the energy for propulsion.
Referring now to FIG. 5 in which there is shown an alternative embodiment of the subject invention wherein like referenced characters refer to like elements. The self-propelled rollerskate 112 disclosed in FIG. 5 includes an articulated frame 16 having a front portion 18 and a rear portion 20 similar to that disclosed in FIG. 1, including a front wheel axle 36 and wheels 32 and 34 affixed to the underside 38 of the front portion 18 by means of a support bracket 114 in a conventional manner. Wheels 32 and 34 are permitted to freely rotate as disclosed earlier. The rear portion 20 of frame 16 is hingedly affixed to the front portion 18 by means of a hinge 22, thus permitting the rear portion 20 to move in a generally vertical direction as shown by arrows 24 and 26. A bracket 104 is provided on the heel portion 100 and contains an adjustment screw 106 adapted to retain an individual's shoe 12 in the same manner as disclosed in the earlier embodiment. The toe portion of shoe 12 is retained in the front portion 18 of frame 16 similarly.
FIG. 6 is a view of the underside of the frame 16 and discloses the location of the driving mechanism for the alternative embodiment of the self-propelled roller skate 12, wherein the driving mechanism is disposed in the central, generally horizontal section 114 of the front portion 18 of the articulated frame 16. The hinge 22 connecting the front portion 18 to the rear portion 20 includes a leaf spring member 116 having one end affixed to the front portion 18 and retained by a detent 118 to insure that the rear portion 20 is urged in an upwardly direction until the weight of an individual is moved to the heel portion of his shoe. The remaining features of the heel portion 100 are identical to the construction described with the first embodiment.
Referring now to FIGS. 6, 7 and 8, wherein there is disclosed enlarged details of the mechanisms set forth in FIGS. 5 and 6. The underside of the central section 114 is provided with a pair of downwardly extending arms 120 and 122 having, at the distal ends, a pair of apertures 124 and 126, respectively, provided therein. A plurality of apertures 128, 129, 130 and 131 are provided on the generally, horizontally disposed central portion 114. These apertures are adapted to receive rivets or nuts and bolts, not shown, which affix the front portion 18 to an individual's shoe or may be utilized with any other suitable means, e.g. plug and socket, shoulder shank and keyhole socket, velcro, etc., to affix the self-propelled mechanism thereto. The underside 38 of the central section 114 is provided with a downwardly extending bracket 132 which has therein a pair of apertures 134 and 136 that function to retain one end of a coil spring 138 and 140, respectively. The other end of coil springs 138 and 140 extend in a forwardly direction towards the base portion 142 of a U-shaped bracket 144 and is provided with arms 146 and 148 that extend rearwardly and are provided with apertures 150 and 152 proximate the distal ends thereof. An additional pair of apertures 154 and 156 are disposed along the length of arms 146 and 148 and are positioned so that they coincide with apertures 124 and 126 provided in arms 120 and 122 of the central section 114 and are adapted to receive pivot pins 158 and 160 therein, thereby providing a pivot point for arms 146 and 148 of U-shaped bracket 144. The base portion 142 of bracket 144 is further provided with a pair of depending ears 162 and 164 which have apertures 166 and 168 provided therein adapted to receive the remaining end of springs 138 and 140 therethrough. The ends 170 and 172 of springs 138 and 140, respectively, are provided with threads thereon and are held in position by a pair of retaining nuts 174 and 176 that may be used to adjust the tension of coil springs 138 and 140 as necessary.
The axle 66 has a pair of wheels 68 and 70 rigidly affixed thereon and is journaled in apertures 150 and 152 provided at the distal end of arms 146 and 148 of U-shaped bracket 144. A ratchet gear 72 is disposed on axle 66 preferably in the central portion thereof.
A ratchet rack 84 extends in a downwardly direction having an aperture provided on one distal end adapted to receive a pivot pin 82 therein. Pivot pin 82 is inserted in aperture 178 provided on the underside of the rearwardly extending section 180 of the front portion 18 of frame 16. A leaf spring 182 is affixed to the underside of the rearwardly extending section 180 and is in intimate contact with ratchet rack 84, urging it in a rearwardly direction to that it comes into intimate contact with the ratchet gear provided on the axle 66 providing cooperative engagement between the teeth 90 appearing on the ratchet rack 84 and the teeth 74 provided on the ratchet gear 72. Movement of the axle 66 and wheels 68 and 70 are in the direction of arrows 94 and 92, respectively, in a manner similar to that described for the earlier embodiment.
By removing the weight of an individual from the front portion 18, the springs 138 and 140 acting upon the base portion 142 of U-shaped bracket 144 urges the axle 66 in the direction of arrow 98, thus moving the axle to the distal end of ratchet rack 84. This may be accomplished by an individual raising his foot off the ground surface 40 or by shifting his weight to the rear portion 20 of the self-propelled roller skate 112 as explained earlier. Movement may be accomplished by either lifting one foot off the surface and then the other in a duck-like fashion or, alternatively, utilizing a heel-toe gait.
The operation of the instant embodiment is exactly the same as the operation of the embodiment disclosed in FIG. 1. The manner of utilizing the self-propelled mechanism relies upon an individual shifting his weight from heel-to-toe alternately between his left and right foot or, as explained earlier, the same priming of the mechanism is accomplished by raising the individual's foot off the walking surface. An individual, after practicing the required movements, can become adept at it and propel along a smooth surface with ease thereby enabling persons unable to raise their feet an ability to be propelled along the surface with a minimum of effort.
Hereinbefore has been disclosed a self-propelled roller skate which may be utilized by individual's having walking problems or unable to expend large amounts of energy. The mechanism is simple, reliable, and readily adaptable to be used with shoes which have been fitted to an individual's foot. It will be understood that various changes in the details, materials, arrangement of parts and operating conditions which have been herein described and illustrated in order to display the nature of the invention may be made by those skilled in the art within the principles and scope of the instant invention.
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A self-propelled roller skate requiring a minimum of energy of the wearer thereof includes an articulated frame having a front portion, which includes the propelling mechanism, and a rear portion, which includes a standing and braking apparatus. The propulsion of the roller skate is accomplished by the wearing individual merely raising the front portion of his foot and shifting his body weight to the heel of the same foot or to the opposite foot. Upon placing the raised foot or portion upon a flat surface and shifting his weight back to that foot or portion, propulsion is accomplished without requiring any additional physical energy.
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FIELD OF THE INVENTION
The present invention relates to a fluid surface texturing device, apparatus incorporating the same and a kit of parts, the use thereof in texturing a fluid surface and a process for texturing a fluid surface.
BACKGROUND OF THE INVENTION
Concrete has been used for many years to provide the wearing surface on highways. The popularity of the technique varies from country to country, and even within countries, for example between UK Highway Authorities, for the reasons given below.
Concrete is perhaps the most durable, and easily repaired of all materials for highways etc., but there are three interrelated drawbacks:
1. The surface's natural smoothness requires texturing for increased friction, and water drainage for the avoidance of skidding and “aquaplaning” when wet;
2. This “texturing” is usually carried out by a stiff brushing or raking as the concrete sets, which is prone to failure, since all texture surface is lost if there is rain at any time in the first 10 hours or so, of the setting process, or by cutting with diamond-tipped rotary blades which is extremely costly and justified only for retexturing runways for example, and leads to excessive, unpleasant audible noise emission as a driving surface;
3 Texturing produced by these methods rapidly wears under traffic, particularly so in areas where high friction is most needed, at corners and, junctions and the like, hence this is not a long term solution.
Asphalt finishes are less durable and need great care to repair properly, but the random surface pattern of particle size, position and gap widths of the surface layer of aggregate, provides a much quieter driving surface, greater friction naturally, and channels for surface water to occupy if not excessive, and to drain in heavy falls.
As a compromise, many roads are laid with a concrete substructure, and an Asphalt topping.
Much research has gone into trying to get concrete surfaces to imitate the performance of asphalt, resulting in the recent successful trials on UK motorways, of so-called “whisper” concrete. A special, aggregate rich surface layer is laid, but the top few millimeters of concrete are given a set-inhibitor, so that the concrete can be removed, this exposing the tips of the aggregate whilst leaving it partially embedded. This apparently provides a dramatic improvement in the required properties.
Unfortunately this chemical technique requires specialised equipment and trained operatives, and due attention to timing, dispersal of inhibitor, removal of the surface cement binder etc. For this reason the application is limited by cost and convenience.
There is therefore a need for a cost effective and convenient apparatus and method for producing a similar result to that of the chemical technique, and in a wide variety of applications, from footpaths, to motorways; for ornamental addition to concrete surfaces, or for discouraging pedestrians from walking in unsafe locations such as roundabout centres and the like.
Moreover there is a need for an apparatus and method for texturing concrete surfaces with acceptable surface flattener and levelness. A standard test method for determining surface flatness and levelness is given in astmE 1155-87. In particular there is a need for an apparatus and method which is self-regulating in terms of surface flatness and levelness produced for a textured surface, for high quality, efficient and reproduceable operation.
We have now surprisingly found a cost effective and convenient apparatus and method for texturing a concrete surface by mechanical means to produce a similar result to that of the chemical technique.
SUMMARY OF THE INVENTION
In its broadest aspect there is provided according to the present invention a device for association with a rotatable powered roller having an elongate cylindrical roll surface adapted to be moved over a surface of newly laid fluid and surrounding formwork, wherein the manner of association is such that the roller surface comprises an elongate substantially cylindrical texturing portion and at least two guide portions, the guide portions being adapted to support the texturing portion at a required level with respect to the fluid surface in manner to ensure partial embedding of texturing material distributed thereon.
Reference herein to formwork is to any vertical surround as necessary in the art to provide a boundary for casting a setable fluid, and includes an edge, cutaway or section of existing surface which is to be infilled or repaired.
Reference herein to a fluid is to any setting, curing or solidifiable fluid commonly used in the construction of load bearing surfaces such as footpaths, roads and the like. In particular, the fluids may include concrete and mixtures thereof with other construction materials.
Reference herein to texturing is to incorporation of a solid aggregate for the purpose of inducing a friction, drainage, decorative or ornamental, obstructive, guiding or marking surface and the like.
The aggregate material as hereinbefore defined may be any solid particulate or shaped object. The material may be comprised of any desired wearing, friction inducing, decorative, obstructive or non-obstructive material such as stone or gravel chippings which may be natural or coloured, depending on the effect required, glass fragments, ground glass, concrete or other composite blocks or formed objects and the like. The aggregate material may be of substantially uniform size or may be of a size distribution selected for graded or random texturing.
A device as hereinbefore defined may be integral or non-integral with a powered roller as hereinbefore defined. A non-integral device may be adapted to engage with or to be attached to the roller. The device may be of fixed or variable nature, or may be one of a plurality of super-imposable devices, whereby the required level of the texturing portion may be selected as desired. It will be appreciated that the required level may vary widely according to the desired purpose and function of texturing, but is generally determined to be in the range of 50 to 80% of the average dimension of the aggregate material to be employed. A desired level may therefore be in the range of 2 mm-200 mm.
For example the required level for providing friction or drainage to a surface may be in the range of 2 mm-10 mm, preferably 3 mm-8 mm, whereas the required level for the purpose of introducing a barrier or obstruction to discourage access by humans or vehicles maybe of the order of 10-200 mm, and the required level for introducing guiding or marking texturing, for example to provide a footpath direction strip for the blind or a visible direction marker to indicate or segregate the paths may be in the region of 5 mm-20 mm, for example 7 mm-15 mm.
In a first aspect of the invention a device comprises two substantially identical sleeves which may be fitted around the rolling surface at either end thereof, the sleeves being constructed of any rigid load bearing material and having a sleeve-wall thickness corresponding to the required level as hereinbefore defined. Preferably each sleeve includes a base of one end having an aperture to receive the supporting axis of the roller, and adapted to abut against the end of the roller thereby maintaining the sleeve in place. The sleeve may include additional projections, attachments and the like for the same purpose, and preferably being readily engaged or released by hand or by simple tool.
A plurality of sleeves may be provided of different internal and external diameters, whereby a required level of the texturing portion of the roller may be obtained by means of placing one or a plurality of sleeves one about the other at each end of the roller. Alternatively a set of sleeves may be of similar internal diameter and of different external diameters, whereby a pair of sleeves may be selected to provide the required level.
In a second embodiment a device comprises a pair of support carriageways adapted to ride on, or near the formwork, and having a vertical aperture or the like to receive the ends of the roller. A carriageway riding on the formwork may comprise a friction surface adapted to enable it to slide, whereas a carriageway riding near the formwork may comprise a wheel base or the like. Each support carriageway may comprise sections enabling the height thereof to be adapted, whereby the required level of the texturing portion of the roller may be obtained, or may comprise a stepped surface having apertures or attachments at different elevations. Alternatively a pair of support carriageways may be selected from pairs of different heights. Alternatively each carriageway may comprise an asymmetric continuous or polygonal sleeve or annulus adapted to be located about each end of the roller, and to be rotated such that the guide portion riding on or near the formwork is of the required distance from the roller axis, thereby providing the required level of the texturing portion.
A rotatable, powered roller as hereinbefore defined may be any roller known in the art, preferably for striking the surface of newly laid concrete by being moved over the surface with the roller surface in slipping contact with the fluid surface and with opposite ends of the roller maintained at the required level of the fluid surface, in order to produce a smooth finish to the surface of the fluid. The roller may be of any desired weight to give the desired compression, and the weight may be adapted from one surface to another or indeed from the first striking stage to the second texturing stage by known means. Preferred means includes introducing a medium such as fluid (water) via entry points in the ends or surface of the roller.
The roller may be part of, or incorporated in, a “paving train” comprising from its leading end, to its following end a moveable hopper to spread the fluid, diagonal or other spreaders to distribute the fluid and control any surcharge of fluid, pokers or other vibrators to remove air, the striking off roller, a second hopper to spread the aggregate material, and a second roller having a texturing portion as hereinbefore defined. This is of particular advantage in laying and texturing rapidly setting surfaces or in the interests of economy in remote areas or for extensive surface areas. A preferred roller includes the roller described in co-pending unpublished International patent application PCT/GB96/01997, the contents of which are incorporated herein by reference. The preferred roller is adapted to be removed from the remainder of the apparatus and dismantled, when not in use, into constituent, smaller parts, and to be re-assembled with use of only some of the constituent parts or with use of all of the parts together with additional parts, whereby the length of the roller may be adapted in convenient manner. The roller suitably comprises internal stressing means for applying longitudinal compression to the roller, between the ends of the roller, so as to reduce the tendency of the roller to sag or become permanently bowed. It is a particular advantage that the roller may be provided as a kit of parts whereby it may be used with enhanced accuracy and convenience on any dimension fluid surface.
A device according to the present invention for use with any such dismantleable roller may be in the form of a roller part of increased diameter which may be readily inserted at the ends of the roller, or may be in the form of a sleeve to be located around a roller part, in place of or together with additional roller parts as desired.
A device comprising a sleeve as hereinbefore defined for use with a conventional non-dismantleable roller may be hinged or resiliently deformable, in manner that it may be expanded about a line parallel to the axis thereof, to provide a lengthwise aperture sufficient to receive the roller, and may be contacted in manner that smooth rolling action is achieved.
A device according to the present invention may conveniently be constructed of any desired natural or synthetic material having the necessary load bearing and substantially resiliently or non-deformable properties, preferably from suitable polymer, metal or composite materials such as steel, aluminium, bronze, nylon, polythene and the like.
It will be appreciated that a device as hereinbefore defined may be readily and simply assembled, attached or associated with a roller in the course of preparing a fluid surface. Moreover the operation of the roller in association with the device requires the same skill and technique as required for operation of the roller itself.
In a further aspect of the invention there is provided a kit of parts comprising one or more devices as hereinbefore defined. Preferably a kit of parts comprises in addition a rotatable, powered roller which is adapted to be removed from the remainder of the apparatus and dismantled, when not used, into constituent, smaller parts as hereinbefore defined. It is a particular advantage that a variety or selection of devices adapted for different purposes may conveniently and compactly be provided in the form of a kit.
In a further aspect of the invention there is provided the use of a device or a kit as hereinbefore defined for texturing a fluid surface. Texturing may be for any desired purpose, such as to provide a friction, drainage, decorative or ornamental, barrier or obstruction, guide or marking surface and the like. Preferably a fluid surface is a surface of newly laid concrete for a highway, footpath or drive, or for a, optionally selective, road or footpath obstacle or obstruction such as a bollard or the like preventing vehicle, motorbike, cycle or pedestrian access, optionally for a vehicle or the like above a given weight or ground clearance. Alternatively texturing may be for the purpose of guiding or marking, for example aggregate material in the form of spheres may be laid in a strip along the length of a newly laid concrete footpath, to provide the familiar foot-sensitive guide for the blind, or in other form for the purpose of segregating or distinguishing distinct pathways and the like.
In a further aspect of the invention there is provided a method for texturing a fluid surface comprising:
distributing aggregate material over the fluid surface in random or predetermined manner;
at a predetermined time thereafter moving a rotatable, powered roller over the fluid surface having the aggregate material thereon, with a texturing portion of the roller surface at the required level above the fluid surface, in order to produce a textured finished surface of the fluid; and
allowing the fluid to set, cure or otherwise solidify.
Preferably the method comprises:
providing a quantity of fluid within formwork; and moving a rotatable, powered roller over a surface of the newly laid fluid, with the roller surface in slipping contact with the fluid surface and with opposite ends of the roller maintained at the required level of the fluid surface by means of the formwork, in order to produce a smooth finish to the surface of the fluid; and
at a predetermined time thereafter texturing the surface as hereinbefore defined.
The aggregate material may be applied by hand or may be distributed from a hopper or a reservoir located in association with the roller or mounted on the formwork whereby it may be distributed directly after preparing the smooth fluid surface, or directly prior to the texturing thereof.
The various stages of the process may be carried out at predetermined times whereby the fluid is prevented from setting prior to texturing thereof, or is allowed to set to a predetermined consistency prior to the texturing thereof. Preferably the concrete is laid and smooth finish applied, whereafter the concrete is allowed to set for up to three hours and aggregate material is applied and the surface textured as hereinbefore defined, whereafter the concrete solidifies in a further six hours or so. This would provide a suitable textured surface for a highway, having adequate embedding and retention of aggregate material.
The texturing may be achieved in one or more passes of the roller over the formwork, or with one or more devices, to gradually achieve the end result of texturing the surface and pressing the aggregate into the surface.
In a further aspect of the invention there is provided a textured fluid surface obtained by the method or with use of the device of the invention.
The invention is now described in non limiting manner with reference to the following figures wherein
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 represents a view of device according to the invention associated with a rotatable, powered roller in use.
FIG. 2 ( 1 ) shows one end of the roller of FIG. 1 without the device according to the invention.
FIG. 2 ( 2 ) shows one end of the roller of FIG. 1 with the device according to the invention.
FIG. 3A shows an end view the roller and device of FIG. 2, in which the roller is being moved across a bed of newly laid fluid concrete.
FIG. 3B shows an end view of the roller and device of FIG. 2, in which the device is embedding scattered pebbles into the fluid surface.
FIG. 3C shows an end view of the roller and device of FIG. 2, in which the device is making a second pass over the embedded pebbles shown in FIG. 3 B.
FIG. 4 represents a view of an alternative conventional powered roller in use.
FIG. 4A is a side view of the carriage and roller assembly of the powered roller of FIG. 4 .
FIG. 4B is an end view of one end of the powered roller of FIG. 4, showing the positioning of a roller within a U-Section beam.
FIG. 4C is a sectional view of the powered roller of FIG. 4, showing the position of the motor with respect to the carriage.
FIG. 4D is a side view of one end of of the powered roller described in FIG. 4, showing the roller end portion in conventional (not-powered) form.
FIG. 5 shows generally alternative devices of the invention associated with the roller of FIG. 4 .
FIG. 5A shows an end view of an embodiment of the inventive device having discreet roller location apertures.
FIG. 5B shows a side elevation view of an embodiment of the inventive device having discreet roller location apertures.
FIG. 5C shows an end view of an embodiment of the inventive device having a pressure/notch fitting secured to a diagonal slot aperture for securing the roller.
FIG. 5D is a side elevation view of the carriageway incorporating the motor of FIG. 4C in combination with a sleeve.
FIG. 5E shows an alternative embodiment of the invention in which a carriageway includes a wheeled guide portion with variable positioning.
FIG. 5F shows an alternative embodiment of the invention in which the carriageway has a sliding guide portions adapted by variable rotation about an off-center axis to vary the elevation of the texturing portion of the roller above the fluid surface.
FIG. 5G shows an alternate embodiment of the invention in which the carriageway includes a series of notched recesses to vary the elevation of the texturing portion of the roller above the fluid surface.
FIG. 6 shows a kit comprising devices of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 is shown a rotatable, powered roller comprising roller ( 1 ) in component parts, comprising texturing and guide portions ( 2 and 3 ) supported on roller ends ( 4 , 5 ) resting upon formwork ( 6 , 7 ) in the form of a section of existing road surface. The roller ( 1 ) is powered by means of a mains powered electric motor ( 8 ). The roller is adapted to be drawn across a bed of still fluid concrete ( 9 ) by means of two handles ( 10 and 11 ). Alternatively the apparatus may comprises two winches (not shown) for drawing the apparatus over the concrete.
In FIG. 1 is shown aggregate material ( 12 ) distributed across the fluid surface. The guide portions ( 3 ) are associated with devices ( 13 and 14 ) comprising two sleeves located about the roller at the ends ( 4 and 5 ) thereof, whereby the guide portion ( 2 ) of the roller is maintained at the required level equal to the thickness of the sleeve walls above the fluid surface. The roller is shown being moved over the formwork so as to press the aggregate partially into the surface.
In FIG. 2 ( 1 ) is shown a roller end ( 4 ) at the level of the fluid surface ( 15 ), the end supports for the roller ends are not shown. The fluid surface is at the height of the formwork ( 6 ). In FIG. 2 ( 2 ) is shown the roller end of FIG. 2 ( 1 ) including a device ( 14 ) as shown in FIG. 1, in manner to provide a guide portion ( 3 ). The texturing portion ( 2 ) of the roller is thereby maintained at a level ( 16 ) equal to the sleeve thickness, t, above the fluid surface ( 15 ). The device includes an end section ( 17 ) which fits around the end of the roller, including an axial aperture ( 18 ) for the roller support and apertures ( 19 ) thereabout to secure the sleeve to the roller. Aggregate material ( 12 ) is shown partially embedded within the fluid surface ( 15 ), and partially compressed to textured surface level ( 16 ) by the texturing portion ( 2 ) of the roller.
In the Figure the roller is extended by guide portion ( 3 ) which projects outwardly across the formwork, whereby the required level may be achieved. In this case the roller ( 1 ) is dismantleable and an additional section is incorporated, which may be an end or middle section, in order to increase the length thereof.
In FIG. 3 is shown the process of the invention employing the device of FIGS. 1 and 2. In FIG. 3A, the roller is moved slowly across the bed of newly laid fluid concrete ( 9 ), with the surface of the roller in slipping contact with the fluid surface. A smooth finish ( 15 ) is obtained behind the roller. In FIG. 3B, texturing material ( 12 ) comprising pebbles have been scattered over the wet concrete and the roller incorporating the device comprising guide portions ( 3 ) is passed over the fluid surface, with the texturing portion of the roller ( 2 ) at the required level above the fluid surface ( 15 ), whereby the pebbles are partially embedded in the fluid surface, leaving a textured surface behind the roller. In FIG. 3C a second pass is made, optionally an overlayer (not shown) is provided in a subsequent stage to seal the aggregate material, without diminishing the textured effect thereof.
FIG. 4 illustrates an alternative conventional apparatus wherein the roller ( 1 ) is rotatably mounted to two carriages ( 32 and 33 ), one having a roller powering motor ( 34 ). The formwork comprises two U section beams ( 35 and 36 ) on their sides. The roller ends rest upon the tops of the beams ( 35 and 36 ) whilst the carriages ( 32 and 33 ) have relatively small guide rollers ( 37 and 38 ) which engage undersides or two top flanges of the beams ( 35 and 36 ) so as to hold the roller ( 1 ) positively down, in contact with the formwork beams ( 35 and 36 ), thereby doing away with the need for handles. The apparatus is drawn over the concrete by two winches ( 39 and 40 ).
In FIG. 4D is shown in side elevation the roller end portion ( 4 ) in conventional form.
In FIG. 5 is shown various embodiments of the roller of FIG. 4 comprising devices according to the invention, in the form of sleeve ( 20 ) or carriageways ( 21 to 24 ), having a variety of variant height adjustment means. In FIGS. 5A and 5B are shown in end and side elevation the carriageway of FIG. 4, according to the present invention, having discrete roller location apertures. The location may alternatively be secured by-pressure or notch fit in a single elongate vertical or diagonal aperture, as shown in FIG. 5 C. In FIG. 5D is shown in side elevation the corresponding carriageway incorporating the motor of FIG. 4, according to the invention, in combination with a sleeve ( 20 ). In FIG. 5E is shown an alternative carriageway ( 22 ) according to the invention having a wheeled guide portion with variable positioning. In FIGS. 5F and 5G are shown alternative carriageways ( 23 ) and ( 24 ) having sliding guide portions adapted by variable rotation about an off-centre axis or by a series of notched recesses locating with formwork ( 35 ) to vary the elevation of the texturing portion ( 16 ) above the fluid surface ( 15 ).
FIG. 6 shows a kit of parts according to the invention as hereinbefore defined, comprising interlocking sleeves of different aggregate wall thickness ( 40 ) or sleeves of different individual wall thickness ( 41 ), roller sections ( 42 ) of different lengths, suitably 2x, 3x and 4x unit lengths, where the unit length is dependant on the intended nature of the surface to be finished, suitably for concrete finishing, the unit length is 0.5-5.1 m, preferably 1 m or thereabouts. The sections ( 42 ) are shown each with an end plate ( 43 ) and a coupling member ( 44 ) (detail not shown). The kit also includes a dedicated end portion ( 45 ), and optional dedicated coupling members ( 46 ).
A tensioning member ( 47 ) is shown in its component parts, comprising cable ( 48 ) of 2x unit length and pairs of rods ( 49 ) each 0.5x, 1x, 1.5x, 2x, 2.5x and 3.5x unit length, or 14 rods ( 50 ) each of 0.5x unit length, or 7 rods ( 50 ) each of 1x unit length.
Further advantages of the invention will be apparent from the foregoing.
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A device and method for association with a rotatable powered roller having an elongate cylindrical roll surface adapted to be moved over a surface of newly laid fluid and surrounding formwork, wherein the manner of association is such that the roller surface includes an elongate substantially cylindrical texturing portion and at least two guide portions, the guide portions being adapted to support the texturing portion at a required level with respect to the fluid surface in a manner to ensure partial embedding of texturing material distributed thereon, use thereof in texturing a fluid surface, method for texturing a fluid surface and a fluid surface obtained thereby.
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BACKGROUND
[0001] Offshore oil and gas operations often utilize a wellhead housing supported on the ocean floor and a blowout preventer stack secured to the wellhead housing's upper end. A blowout preventer stack is an assemblage of blowout preventers and valves used to control well bore pressure. The upper end of the blowout preventer stack has an end connection or riser adapter (often referred to as a lower marine riser packer or LMRP) that allows the blowout preventer stack to be connected to a series of pipes, known as riser, riser string, or riser pipe. Each segment of the riser string is connected in end-to-end relationship, allowing the riser string to extend upwardly to the drilling rig or drilling platform positioned over the wellhead housing.
[0002] The riser string is supported at the ocean surface by the drilling rig. This support takes the form of a hydraulic tensioning system and telescoping (slip) joint that connect to the upper end of the riser string and maintain tension on the riser string. The telescoping joint is composed of a pair of concentric pipes, known as an inner and outer barrel, that are axially telescoping within each other. The lower end of the outer barrel connects to the upper end of the aforementioned riser string. The hydraulic tensioning system connects to a tension ring secured on the exterior of the outer barrel of the telescoping joint and thereby applies tension to the riser string. The upper end of the inner barrel of the telescoping joint is connected to the drilling platform. The axial telescoping of the inner barrel within the outer barrel of the telescoping joint compensates for relative elevation changes between the rig and wellhead housing as the rig moves up or down in response to the ocean waves.
[0003] According to conventional practice, various auxiliary fluid lines are coupled to the exterior of the riser tube. Exemplary auxiliary fluid lines include choke, kill, booster, and hydraulic fluid lines. Choke and kill lines typically extend from the drilling rig to the wellhead to provide fluid communication for well control and circulation. The choke line is in fluid communication with the borehole at the wellhead and may bypass the riser to vent gases or other formation fluids directly to the surface. According to conventional practice, a surface-mounted choke valve is connected to the terminal end of the choke conduit line. The downhole back pressure can be maintained substantially in equilibrium with the hydrostatic pressure of the column of drilling fluid in the riser annulus by adjusting the discharge rate through the choke valve.
[0004] The kill line is primarily used to control the density of the drilling mud. One method of controlling the density of the drilling mud is by the injection of relatively lighter drilling fluid through the kill line into the bottom of the riser to decrease the density of the drilling mud in the riser. On the other hand, if it is desired to increase mud density in the riser, a heavier drilling mud is injected through the kill line.
[0005] The booster line allows additional mud to be pumped to a desired location so as to increase fluid velocity above that point and thereby improve the conveyance of drill cuttings to the surface. The booster line can also be used to modify the density of the mud in the annulus. By pumping lighter or heavier mud through the booster line, the average mud density above the booster connection point can be varied. While the auxiliary lines provide pressure control means to supplement the hydrostatic control resulting from the fluid column in the riser, the riser tube itself provides the primary fluid conduit to the surface.
[0006] A hose or other fluid line connection to each auxiliary fluid line coupled to the exterior of the riser tube is provided at the telescoping joint via a pipe or equivalent fluid channel The pipe is often curved or U-shaped, and is accordingly termed a “gooseneck” conduit. In the course of drilling operations, a gooseneck conduit may be detached from the riser, for example, for maintenance or to permit the raising of the riser through the drilling floor, and reattached to the riser to provide access to the auxiliary fluid lines. The gooseneck conduits are typically coupled to the auxiliary fluid lines via threaded connections.
SUMMARY
[0007] A gooseneck conduit system for use with a telescoping joint of a subsea riser is disclosed herein. In one embodiment, a riser telescoping joint includes a tube and a gooseneck conduit assembly affixed to the tube. The gooseneck conduit assembly includes a gooseneck conduit extending radially from the tube, and a tenon projecting from a rear face of the gooseneck conduit. The width of the tenon increases with distance from the rear face. The riser telescoping joint also includes a mortise channel extending lengthwise along the tube. The mortise channel interlocks with the tenon to laterally secure the gooseneck conduit assembly to the tube.
[0008] In another embodiment, a gooseneck conduit unit includes a plate, a gooseneck conduit, and a bumper. The gooseneck conduit is removably mounted to the plate. The bumper is coupled to a rear face of the gooseneck conduit. The bumper includes a tenon that guides the gooseneck conduit unit into position on a telescoping joint.
[0009] In a further embodiment, a system includes a telescoping joint. The telescoping joint includes an alignment ring and a gooseneck conduit assembly. The alignment ring is circumferentially coupled to a tube of the telescoping joint. The alignment ring includes a longitudinal mortise channel The gooseneck conduit assembly is coupled to the alignment ring. The gooseneck conduit assembly includes a gooseneck conduit and a tenon. The tenon slidingly engages sides of the mortise channel to secure the gooseneck conduit assembly to the alignment ring.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For a detailed description of exemplary embodiments of the invention, reference will now be made to the accompanying drawings in which:
[0011] FIGS. 1A-1B show a drilling system including a gooseneck conduit system in accordance with various embodiments;
[0012] FIG. 2 shows a telescoping joint in accordance with various embodiments;
[0013] FIG. 3 shows a top view of a plurality of gooseneck conduit assemblies in accordance with various embodiments;
[0014] FIG. 4 shows an elevation view of a support collar and gooseneck conduit assemblies in accordance with various embodiments;
[0015] FIG. 5 shows a perspective view of a support collar and gooseneck conduit assemblies in accordance with various embodiments; and
[0016] FIG. 6 shows a cross sectional view of a support collar and gooseneck assemblies in accordance with various embodiments.
NOTATION AND NOMENCLATURE
[0017] Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, companies may refer to a component by different names This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections.
DETAILED DESCRIPTION
[0018] The following discussion is directed to various embodiments of the invention. The drawing figures are not necessarily to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.
[0019] The size and weight of the gooseneck conduits, and the location of the attachment points of the conduits to the telescoping joint and the auxiliary fluid lines, makes installation and/or retrieval of the conduits a labor-intensive process. Consequently, gooseneck conduit handling operations can be time consuming and costly. Embodiments of the present disclosure include a gooseneck conduit system that reduces handling time and enhances operational safety. Embodiments of the conduit system disclosed herein can provide simultaneous connection of gooseneck conduits to a plurality of auxiliary fluid lines with no requirement for manual handling or connection operations. Embodiments include hydraulically and/or mechanically operated locking mechanisms that secure the conduit system to the telescoping joint and the auxiliary fluid lines. The conduit system may be hoisted into position on the telescoping joint, and attached to the telescoping joint and the auxiliary fluid lines via the provided locking mechanisms. Thus, embodiments allow gooseneck conduits to be quickly and safely attached to and/or removed from the telescoping joint.
[0020] FIGS. 1A-1B show a drilling system 100 in accordance with various embodiments. The drilling system 100 includes a drilling rig 126 with a riser string 122 and blowout preventer stack 112 used in oil and gas drilling operations connected to a wellhead housing 110 . The wellhead housing 110 is disposed on the ocean floor with blowout preventer stack 112 connected thereto by hydraulic connector 114 . The blowout preventer stack 112 includes multiple blowout preventers 116 and kill and choke valves 118 in a vertical arrangement to control well bore pressure in a manner known to those of skill in the art. Disposed on the upper end of blowout preventer stack 112 is riser adapter 120 to allow connection of the riser string 122 to the blowout preventer stack 112 . The riser string 122 is composed of multiple sections of pipe or riser joints 124 connected end to end and extending upwardly to drilling rig 126 .
[0021] Drilling rig 126 further includes moon pool 128 having telescoping joint 130 disposed therein. Telescoping joint 130 includes inner barrel 132 which telescopes inside outer barrel 134 to allow relative motion between drilling rig 126 and wellhead housing 110 . Dual packer 135 is disposed at the upper end of outer barrel 134 and seals against the exterior of inner barrel 132 . Landing tool adapter joint 136 is connected between the upper end of riser string 122 and outer barrel 134 of telescoping joint 130 . Tension ring 138 is secured on the exterior of outer barrel 134 and connected by tension lines 140 to a hydraulic tensioning system as known to those skilled in the art. This arrangement allows tension to be applied by the hydraulic tensioning system to tension ring 138 and telescoping joint 130 . The tension is transmitted through landing tool adapter joint 136 to riser string 122 to support the riser string 122 . The upper end of inner barrel 132 is terminated by flex joint 142 and diverter 144 connecting to gimbal 146 and rotary table spider 148 .
[0022] A support collar 150 is coupled to the telescoping joint 130 , and the auxiliary fluid lines 152 are terminated at seal subs retained by the support collar 150 . One or more gooseneck conduit assemblies 154 are coupled to the support collar 150 and to the auxiliary fluid lines 152 via the seal subs retained by the support collar 150 . Each conduit assembly 154 is a conduit unit that includes one or more gooseneck conduits 156 . A hose 158 or other fluid line is connected to each gooseneck conduit 156 for transfer of fluid between the gooseneck conduit 156 and the drilling rig 126 . In some embodiments, the connections between the hoses 158 and/or other rig fluid lines and the gooseneck conduits 156 are made on the rig floor, and thereafter the gooseneck conduit assembly 154 is lowered onto the telescoping joint 130 .
[0023] The gooseneck conduit assembly 154 includes locking mechanisms that secure the conduit assembly 154 to the telescoping joint 130 . The conduit assembly 154 can be lowered onto the support collar 150 using a crane or hoist. In some embodiments, the conduit assembly 154 can be connected to hydraulic lines that actuate the locking mechanisms. Thus, embodiments allow the gooseneck conduits 156 to be quickly and safely fixed to and/or removed from the telescoping joint 130 while reducing the manual effort required to install and/or remove the gooseneck conduits 156 .
[0024] FIG. 2 shows the telescoping joint 130 in accordance with various embodiments. The auxiliary fluid lines 152 are secured to the telescoping joint 130 . The uphole end of each auxiliary fluid line 152 is coupled to a seal sub 206 at the support collar 150 . The support collar 150 is coupled to and radially extends from the telescoping joint 130 . In some embodiments, the support collar 150 includes multiple connected sections (e.g., connected by bolts) that join to encircle the telescoping joint 130 .
[0025] The gooseneck conduit assembly 154 includes one or more locking mechanisms, and a plurality of gooseneck conduits 156 . As the gooseneck conduit assembly 154 is positioned on the support collar 150 , each gooseneck conduit 156 engages a seal sub 206 and is coupled to an auxiliary fluid line 152 . The locking mechanisms secure the gooseneck conduit assembly 154 to the support collar 150 , and secure each gooseneck conduit 156 to a corresponding auxiliary fluid line 152 . In some embodiments, the locking mechanisms are hydraulically operated. In other embodiments, the locking mechanisms are mechanically operated. The locking mechanisms may be either hydraulically or mechanically operated in some embodiments. The gooseneck conduits 156 may include swivel flanges 208 for connecting the conduits 156 to fluid lines 158 .
[0026] FIG. 3 shows a top view of a plurality of gooseneck conduit assemblies 154 in accordance with various embodiments. Each gooseneck conduit assembly 154 includes one or more gooseneck conduits 156 . Each gooseneck conduit assembly 154 includes a top plate 302 and fasteners 312 that connect the top plate 302 to underlying structures explained below. The gooseneck conduit assembly 154 includes a projection or tenon 306 for aligning and locking the gooseneck conduit assembly 154 to the telescoping joint 130 . Some embodiments of the gooseneck conduit assembly 154 include a tenon 306 coupled to each gooseneck conduit 156 . In some embodiments, the tenon 306 may be trapezoidal, or fan-shaped to form a dove-tail tenon. Other embodiments may include a differently shaped tenon 306 . The tenon 306 may be formed by a bumper attached to the rear face 318 of the gooseneck conduit 156 , with the bumper, and thus the tenon 306 , extending along the length of the rear face 318 . In some embodiments, the tenon 306 may be made of bronze or another suitable material. In some embodiments, the tenon 306 may be part of the gooseneck conduit 156 .
[0027] An alignment guidance ring 316 is circumferentially attached to the telescoping joint 130 . The alignment guidance ring 316 includes channel mortises 304 that receive, guide the gooseneck conduits 156 into alignment with the seal subs 206 , and retain the tenons 306 as the gooseneck conduit assembly 154 is lowered onto the telescoping joint 130 . Consequently, the mortises 304 are shaped to mate with and slidingly engage the tenons 306 (i.e., a trapezoids, dove-tails, etc). The channel mortises 304 may narrow with proximity to the support collar 150 (with proximity to the bottom of the alignment ring 316 ) Similarly, the tenons 306 may narrow with distance from the top plate 302 (with proximity to the bottom of the rear face 318 of the gooseneck conduit 156 ). The tenons 306 and mortises 304 are dimensioned to securely interlock.
[0028] The gooseneck conduit assembly 154 includes locking mechanisms that secure the gooseneck conduit assembly 154 to the telescoping joint 130 . Embodiments may include one or more locking mechanisms that are mechanically or hydraulically actuated. For example, embodiments may include a primary and a secondary locking mechanism. Hydraulic secondary backup locks 308 are included on some embodiments of the gooseneck conduit assembly 154 . The hydraulic secondary locks include a hydraulic cylinder that operates the lock. Other embodiments include mechanical secondary backup locks 310 . In some embodiments, the secondary backup locks secure the primary locking mechanisms into position. Lock state indicators 314 show the state of conduit assembly locks. For example, extended indicators 314 indicate a locked state, and retracted indicators 314 indicate an unlocked state.
[0029] FIG. 4 shows an elevation view of the support collar 150 and gooseneck conduit assemblies 154 in accordance with various embodiments. The gooseneck conduit assembly 154 A includes two gooseneck conduits 156 , and is unlocked and separated from the telescoping joint 130 , and positioned above the support collar 150 . The gooseneck conduit assembly 154 B includes three gooseneck conduits 156 , and is secured to the telescoping joint 130 and associated seal subs 206 . Each gooseneck conduit 156 is replaceably fastened to a lower support plate 404 by bolts or other attachment devices. The upper support plate 302 is attached to the lower support plate 404 . The support collar 150 retains the seal subs 206 via clamps 412 attached to the support collar 150 by bolts or other fastening devices.
[0030] The alignment and guidance ring 316 is secured to the telescoping joint 130 . The alignment and guidance ring 316 may be formed from a plurality of ring sections joined by bolts or other fastening devices. The alignment and guidance ring 316 includes a locking channel 406 . The gooseneck conduit assembly 154 B rests on surface 502 ( FIG. 5 ) of the alignment and guidance ring 316 , and as discussed above, the tenons 306 interlock with the mortises 304 to laterally secure the gooseneck conduit assembly 154 B. The locking member 408 extends from the gooseneck conduit assembly 154 B into the locking channel 406 to prevent movement of the gooseneck conduit assembly 154 B upward along the telescoping joint 130 .
[0031] FIG. 5 shows a perspective view of the support collar 150 and the gooseneck conduit assemblies 154 as arranged in FIG. 4 .
[0032] FIG. 6 shows a cross-sectional view of the support collar 150 and gooseneck conduit assemblies 154 as arranged in FIG. 4 . Embodiments of the gooseneck conduits assemblies 154 may include any combination of hydraulic and mechanical primary and secondary locks. The gooseneck conduit assembly 154 B includes a hydraulic primary lock 618 and a hydraulic secondary lock 308 . The components of the hydraulic primary lock 618 are disposed between the upper and lower support plates 302 and 404 . The hydraulic primary lock 618 includes a hydraulic cylinder 612 coupled to the locking member 408 for extension and retraction of the locking member 408 .
[0033] The components of the hydraulic secondary lock 308 are secured to the upper plate 302 by hydraulic cylinder support plate 606 . The hydraulic secondary lock 308 includes a hydraulic cylinder 602 coupled to a locking pin 604 for extension and retraction of the locking pin 604 . When the locking member 408 has been extended, extension of the locking pin 604 secures the locking member 408 in the extended position. In some embodiments, the locking member 408 includes a passage 608 . The locking pin 604 extends into the passage 608 to secure the locking member 408 in the extended position.
[0034] The gooseneck conduit assembly 154 A includes a hydraulic primary lock 618 and a mechanical secondary lock 310 . As described above, the components of the hydraulic primary lock 618 , including the hydraulic cylinder 612 , and the locking member 408 , are disposed between the upper and lower support plates 302 and 404 . In some embodiments, the locking member 408 may be retracted by mechanical rather than hydraulic means. For example, force may be applied to the state indicator 314 to retract the locking member 408 from the locking channel 406 . The mechanical secondary lock 310 comprises an opening 624 that allows a bolt or retention pin to be inserted into the passage 608 of the locking member 408 when the locking member 408 is extended.
[0035] An upper split retainer 626 and a lower split retainer 622 are attached to the support collar 150 to reduce support collar 150 radial loading. The upper split retainer 626 is bolted to the upper side of the support collar 150 , and the lower split retainer 622 is bolted to the lower side of the support collar 150 . Each split retainer 626 , 622 comprises two sections. The two sections of each retainer 626 , 622 abut at a position 90° from the location where the support collar sections are joined. The upper split retainer 626 includes a tapered surface 628 on the inside diameter that retains and positions the support collar 150 on the telescoping joint 130 . The support collar 150 also includes a key structure (not shown) for aligning the support collar 150 with a keying structure of the telescoping joint and preventing rotation of the support collar 150 about the telescoping joint 130 .
[0036] Each gooseneck conduit 156 includes an arcing passage 614 extending through the gooseneck conduit 156 for passing fluid between the auxiliary fluid line 152 and the hose 158 . The gooseneck conduit assembly 156 may be formed by a casting process, and the thickness of material between the passage 614 and the exterior surface of the gooseneck conduit 156 may exceed the diameter of the passage 614 (by 2-3 or more times in some embodiments) thereby enhancing the strength and service life of the gooseneck conduit 156 . The gooseneck conduit 156 includes a socket 630 that sealingly mates with the seal sub 206 to couple the gooseneck conduit 156 to the auxiliary fluid line 152 . The socket 630 includes grooves 616 for holding a sealing device, such as an O-ring, that seals the connection between the gooseneck conduit 156 and the sealing sub 206 .
[0037] The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.
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A gooseneck conduit system for use with a telescoping joint of a subsea riser. In one embodiment, a riser telescoping joint includes a tube and a gooseneck conduit assembly affixed to the tube. The gooseneck conduit assembly includes a gooseneck conduit extending radially from the tube, and a tenon projecting from a rear face of the gooseneck conduit. The width of the tenon increases with distance from the rear face. The riser telescoping joint also includes a mortise channel extending along the length of the tube. The mortise channel is interlocks with the tenon and laterally secures the gooseneck conduit assembly to the tube.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit, under 35 U.S.C. 120 of U.S. patent application Ser. No. 09/500,185, filed Feb. 7, 2000, pending.
BACKGROUND OF INVENTION
[0002] This application is a continuation-in-part application of pending U.S. patent application Ser. No. 09/500,185 filed on Feb. 7, 2000 (Now U.S. Pat. No. 6,263,671), which is a continuation-in-part of U.S. patent application Ser. No. 08/971,235 filed on Nov. 15, 1997 (Now U.S. Pat. No. 6,041,598). The above referenced patent applications are hereby incorporated herein by reference.
[0003] 1. Field of the Invention
[0004] The present invention relates, generally, to heat engines. More particularly, the invention relates to Stirling cycle heat engines with a cylinder containing a working fluid and a piston moving therein.
[0005] 2. Background Information
[0006] The maximum Stirling engine efficiency is related to the Carnot efficiency which is governed by the ratio of maximum working fluid temperature relative to the minimum fluid temperature. Improvements in technologies which increase the margin between the two temperature extremes is beneficial in terms of total cycle efficiency. The lower working fluid temperature is typically governed by the surrounding air or water temperature; which is used as a cooling source. The main area of improvements result from an increase in the maximum working temperature. The maximum temperature is governed by the materials which are used for typical Stirling engines. The materials, typically high strength Stainless Steel alloys, are exposed to both high temperature and high pressure. The high pressure is due to the Stirling engines requirement of obtaining useful power output for a given engine size. Stirling engines can operate between 50 to 200 atmospheres internal pressure; for high performance engines.
[0007] Since Stirling engines are closed cycle engines, heat must travel through the container materials to get into the working fluid. These materials typically are made as thin as possible to maximize the heat transfer rates. The combination of high pressures and temperatures has limited Stirling engine maximum temperatures to around 800° C. Ceramic materials have been investigated as a technique to allow higher temperatures, however their brittleness and high cost have made them difficult to implement.
[0008] U.S. Pat. No. 5,611,201, to Houtman, shows an advanced Stirling engine based on Stainless Steel technology. This engine has the high temperature components exposed to the large pressure differential which limits the maximum temperature to the 800° C. range. U.S. Pat. No. 5,388,410, to Momose et al., shows a series of tubes, labeled part number 22 a through d, exposed to the high temperatures and pressures. The maximum temperature is limited by the combined effects of the temperature and pressure on the heating tubes. U.S. Pat. No. 5,383,334 to Kaminishizono et al, again shows heater tubes, labeled part number 18, which are exposed to the large temperature and pressure differentials. U.S Pat. No. 5,433,078, to Shin, also shows the heater tubes, labeled part number 1, exposed to the large temperature and pressure differentials. U.S Pat. No. 5,555,729, to Momose et al., uses a flattened tube geometry for the heater tubes, labeled part number 15, but is still exposed to the large temperature and pressure differential. The flat sides of the tube add additional stresses to the tubing walls. U.S Pat. No. 5,074,114, to Meijer et al., also shows the heater pipes exposed to high temperatures and pressures.
[0009] The Stirling engine disclosed in the inventor's U.S. Pat. No. 6,041,598 overcomes the limitations and shortcomings of the above prior art by providing a dual shell pressure chamber. An inner shell surrounds the heat transfer tubing and the regenerator. The portion surrounding the heat transfer tubing contains a thermally conductive liquid metal to facilitate heat transfer from a heat source to the heat transfer tubing and also to transmit external pressure to the heat transfer tubing. An outer shell that acts as a pressure vessel surrounds the inner shell and contains a thermally insulating liquid between the inner and outer shells. Pressure of the working fluid as it flows through the regenerator is transmitted through the inner shell to the insulating liquid and back across the inner shell to the liquid metal surrounding the heat transfer tubing. This system tends to balance the pressure across the heat transfer tubing and the inner shell, thereby allowing the engine to operate with the working fluid at a high pressure to generate significant power while keeping the wall of the heat transfer tubing thin to facilitate heat transfer through it.
[0010] An anticipated use of the inventor's dual shell Stirling engine is to run a 25 KW electrical generator. For that use, and others, the required power output of the engine may not be constant. Throttling of the engine is, therefore, probably necessary.
[0011] Throttling of Stirling engines is typically accomplished by varying the amount of working fluid inside the engine. With this technique a significant amount of pumping and valving hardware is required to move the working fluid. This is complicated by the high working pressures which increases the size of the pumping hardware. A second technique to throttle the Stirling engine involves opening ports within the engine which are connected to dead (non-working) volumes or reservoirs. That technique increases the total system volume which lowers the power but also results in a significant reduction in efficiency due the larger dead volume which the engine is exposed to for the entire piston stroke. Houtman and Meijer et al. disclose another throttling technique that uses a variable angle plate connected directly to each piston. Reducing the plate angle results in reduced movement of the piston, resulting in reduced power levels. That throttling technique has the disadvantage of a higher system weight due to the large loads generated when converting the wobble motion of the plate to torque.
[0012] The present invention provides a throttle for a Stirling engine which overcomes the limitations and shortcomings of the prior art.
SUMMARY OF INVENTION
[0013] The present invention provides an apparatus and method for throttling a heat engine having a cylinder containing a working fluid with a piston moving therein. A plurality of cylinder ports through a side portion of the cylinder provide fluid communication between an interior portion of the cylinder and a reservoir area when the piston is below the cylinder ports. A throttle control device selectively opens or closes a number of the cylinder ports to allow a portion of the working fluid contained in the cylinder to move between the cylinder and the reservoir area through the cylinder ports and vary the pressure in the portion of the cylinder above the piston.
[0014] The throttle control device includes a sleeve disposed around a portion of the cylinder. The sleeve has a plurality of throttle ports through it and moves relative to the cylinder, preferably rotationally, to selectively communicate a number of the throttle ports with a number of the cylinder ports to thereby open the cylinder ports so communicated.
[0015] In one embodiment the cylinder ports are arranged in groups of vertically aligned ports and the throttle ports are arranged in groups of a stepped series of ports spaced to match the cylinder ports so that as the sleeve is rotated, an increasing number of cylinder ports are opened higher up the cylinder.
[0016] In another embodiment, with the cylinder ports also arranged in groups of vertically aligned ports, the throttle ports are arranged in groups diagonally such that as the sleeve is rotated, a single cylinder port per group of cylinder ports is opened higher up the cylinder.
[0017] In yet another embodiment, the cylinder ports are arranged in a single circumferential row around the cylinder and the throttle ports are arranged in a single circumferential row on the sleeve such that each throttle port aligns with each corresponding cylinder port. The sleeve rotates between a position that allows the cylinder ports to be fully open and a position that allows the cylinder ports to be completely closed, with variable positioning therebetween to thereby vary the amount the cylinder ports open.
[0018] The preferred mechanism for the throttle control device includes a throttle collar attached to the cylinder that supports the throttle sleeve. A throttle worm gear is attached to the throttle sleeve and is driven by a throttle control worm that engages the throttle worm gear to rotationally position the throttle sleeve about the cylinder to selectively communicate a number of the throttle ports with a number of the cylinder ports to thereby open the cylinder ports so communicated.
[0019] There is preferably a throttle fairing that surrounds the throttle control device and provides a pressure fairing to contain the working fluid passing through the cylinder ports. The throttle fairing has a series of throttle vents that provide fluid communication between the reservoir area and an area inside of the throttle fairing.
[0020] Preferably there is also a check valve in the piston which allows working fluid in the reservoir area to move through it into the interior area of the cylinder when pressure in the reservoir area exceeds that of the interior area of the cylinder.
[0021] To throttle the heat engine, the ports in the cylinder are selectively opened to allow communication between the reservoir area and the interior portion of the cylinder above the piston when the piston is below the ports. Working fluid vents from the interior portion of the cylinder through the open ports to the reservoir area as the piston moves up in the cylinder toward the open ports to prevent significant compression of the working fluid in the cylinder. The venting is stopped by blocking the open ports with the piston as the piston moves up past the ports to thereby resume compression of the working fluid in the cylinder. The pressure produced during compression of the working fluid is therefore reduced from that produced when the ports in the cylinder are closed, thereby effectively throttling the engine.
[0022] Pressure is increased again by closing the open ports and moving working fluid from the reservoir area to the interior area of the cylinder above the piston, preferably through a check valve in the piston, to restore the amount of working fluid in the interior area of the cylinder above the piston, thereby allowing higher pressures to be produced during compression of the working fluid by the piston.
[0023] The features, benefits and objects of this invention will become clear to those skilled in the art by reference to the following description, claims and drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0024] [0024]FIG. 1 is a longitudinal vertical cross sectional view showing the overall arrangement for a complete dual shell Stirling engine.
[0025] [0025]FIG. 2 is a side elevational view of a section of the cylinder in the region of the throttle showing the ports through the cylinder.
[0026] [0026]FIG. 3 is a side elevational view of the throttle sleeve, throttle worm gear and throttle control worm.
[0027] [0027]FIG. 4 is the view of FIG. 2 showing another embodiment for the configuration of the ports.
[0028] [0028]FIG. 5 is the view of FIG. 3 showing another embodiment of the throttle sleeve corresponding to the port configuration showing FIG. 4.
[0029] [0029]FIG. 6 is a cross sectional view of a portion of the cylinder and throttle sleeve at a port when the throttle sleeve is positioned such that the port is open.
DETAILED DESCRIPTION
[0030] In the following description of the invention, the components are illustrated and described in a vertical orientation with the cylinder located above the lower housing. Terms such as upper, lower, above and below are used to describe the relative positions of components and are not intended to indicate a quality or locational requirement since the cylinder can be oriented in any position relative to the housing and crankshaft.
[0031] Referring to FIG. 7, components of a dual shell Stirling engine having a power piston 12 that drives an output crankshaft 46 are illustrated. A working fluid, such as Helium, is contained in cylinder 20 above power piston 12 and is shuttled through heat transfer tubing 14 , regenerator 16 , and cooling pipes 18 by the action of a displacer piston 10 . An inner shell 30 surrounds the heat transfer tubing 14 and regenerator 16 . The upper portion 32 of inner shell 30 contains a liquid metal region 34 filled with a thermally conductive liquid metal, such as silver, which surrounds the heat transfer tubing 14 . The regenerator 16 is preferably a coiled annulus of thin material disposed between cylinder 20 and inner shell 30 . Outer shell 60 surrounds inner shell 30 and acts as a pressure vessel. The inner shell 30 , outer shell 60 and flange 38 bound a pressure backup region 42 . The pressure backup region is filled preferably with an insulating liquid material to provide pressure backup against inner shell 30 and, consequently through liquid metal region 34 , to heat transfer tubing 14 .
[0032] Lower housing 22 has a reservoir area 24 between a pair of crankshaft end plates 50 which acts as a reservoir for the working fluid and is in fluid communication with the working fluid in cylinder 20 through throttle ports 40 in cylinder 20 . Low pressure seals and bearings 31 prevent the working fluid in reservoir area 24 from escaping into the space 52 outside of crankshaft end plates 50 , which is preferably pressurized with ambient air to approximately the same pressure as that in reservoir area 24 . Throttling is accomplished by controlling the openings of throttle ports 40 in cylinder 20 .
[0033] Referring also to FIG. 2, a portion of cylinder 20 adjacent to throttle sleeve 28 has a series of cylinder ports 40 drilled into its side so that when the power piston 12 is at bottom dead center, the cylinder ports 40 are completely above the power piston 12 and allow fluid communication between the area inside cylinder 20 above power piston 12 and the reservoir area 24 in lower housing 22 . Open cylinder ports 40 allow the working fluid in cylinder 20 to vent to reservoir area 24 as the power piston 12 rises, thus preventing compression in the region above the power piston 12 . As the power piston 12 moves up cylinder 20 beyond cylinder ports 40 , the region above the power piston 12 is sealed and compressed. The start of the sealing is dependent on the throttle port sequence determined by the throttle control device as follows.
[0034] Cylinder ports 40 are arranged in groups circumferentially around cylinder 20 . Each group has a plurality of vertically oriented ports 40 , preferably three ports per group. Referring also to FIG. 3, throttle sleeve 28 has groupings of throttle ports 41 arranged so as to provide a stepped series of ports spaced vertically to match the cylinder ports 40 in cylinder 20 . A blank portion 45 separates each grouping of throttle ports 41 around the throttle sleeve 28 . The throttle sleeve 28 fits around the cylinder 20 with a snug fit so as to provide a seal between the throttle sleeve 28 and the cylinder 20 , but loose enough that the throttle sleeve 28 can move relative to cylinder 20 . Sealing around ports 40 is accomplished by washers 47 , preferably made of material such as Teflon, which are installed in a countersunk area around ports 40 such that the tops of the washer extend slightly beyond the outer surface of cylinder 20 . FIG. 4 illustrates the relationship between washer 47 , cylinder 20 and sleeve 28 . Compressibility of washer 47 is preferably provided by a resilient O-ring 56 behind washer 47 .
[0035] The throttle control device functions preferably by rotating throttle sleeve 28 around the cylinder 20 through the distance of each grouping of throttle ports 41 . There may be other configurations for sleeve 28 and throttle ports 41 that may allow sleeve 28 to move axially, or a combination of axially and rotationally, rather than rotate to accomplish a similar result, but the preferred motion of sleeve 28 is simple rotation around cylinder 20 . When the blank portion 45 covers cylinder ports 40 , throttle sleeve 28 provides a complete seal and a full-throttle condition. As the throttle sleeve 28 is rotated, an increasing number of throttle ports 41 communicate with cylinder ports 40 higher up cylinder 20 which allow the working fluid to vent from the area above the power piston 12 into the throttle housing 48 and to reservoir area 24 . The higher the cylinder ports 40 , the more power piston 12 has to travel without significantly compressing the working fluid in the cylinder 20 . Once the power piston 12 moves past the open cylinder ports 40 , the compression continues in the cylinder 20 ; but since there is less working fluid in cylinder 20 , the pressure produced by the compression is reduced. This reduction in pressure reduces the total power produced, and effectively throttles the engine. It is also possible that only one cylinder port 40 per group need be opened at a time to allow adequate venting. In that case, the throttle ports 41 for each grouping on throttle sleeve 28 could be arranged diagonally such as is illustrated in FIG. 5.
[0036] Referring again to FIG. 7, once the throttle sleeve 28 is rotated to a higher throttle position, thereby covering more cylinder ports 40 , at the bottom of the stroke of power piston 12 , the pressure in cylinder 20 above power piston 12 would be less than that in reservoir area 24 and some of the working fluid in reservoir area 24 flows back into the cylinder through a check valve 54 , preferably in the top of power piston 12 , to re-pressurize cylinder 20 until the average pressures are equalized. In steady-state operation, when the power piston 12 is at the bottom of its stroke, the pressure in cylinder 20 above power piston 12 equals that in reservoir area 24 and there is no significant movement of the working fluid through check valve 54 .
[0037] A throttle fairing 48 and throttle fairing blister 49 provide a pressure fairing for the throttle sleeve 28 to contain the working fluid. The throttle fairing 48 has a series of throttle vents 44 located at the lower side of the throttle fairing 48 on the surface of the lower housing 22 . The throttle vents 44 provide a means for the working fluid, preferably Helium, to move from the cylinder 20 into the reservoir area 24 of lower housing 22 .
[0038] As throttle sleeve 28 rotates about cylinder 20 , it is supported by a throttle collar 42 attached to the outside of cylinder 20 . The throttle control device includes a throttle worm gear 43 attached to the throttle sleeve 28 and a throttle control worm 36 that engages the throttle worm gear 43 and drives it to rotationally position the throttle sleeve 28 . The combination of the throttle control worm 36 and the throttle worm gear 43 provide a means to reduce the gearing to improve the positioning accuracy of the throttle sleeve 28 . It is possible to control motion of throttle sleeve 28 such that only portions of cylinder ports 40 are opened, thereby providing even finer throttle control.
[0039] Referring to FIGS. 6 and 7, another embodiment for the throttle has only a single cylinder port 140 at each circumferential location rather than a group of vertically oriented ports. The single circumferential row of ports 140 is preferably at approximately the same location as the uppermost port of the groups of ports 40 illustrated in FIG. 2. Throttle sleeve 128 has a corresponding series of single throttle ports 141 circumferentially arranged around it that match the locations of the cylinder ports 140 . The fine positional control of throttle sleeve 128 allows the sleeve to rotate between a position that allows the cylinder ports 140 to be fully open and a position that allows the cylinder ports 140 to be completely closed, with variable positioning therebetween to thereby vary the amount the cylinder ports 140 open. This effectively creates a variable orifice at each port. The amount of working fluid that vents through ports 140 is dependent on how open ports 140 are and the speed of the engine. Higher rpm as well as smaller openings reduce the amount of working fluid that vents.
[0040] A feature of the throttling system of the present invention is the complete sealing of the upper cylinder region after the power piston 12 has passed the cylinder ports 40 . The advantage of this is that the engine will operate at a much higher efficiency at partial power than with a dead-volume throttling system which maintains the increased dead volume over the complete stroke. The reason for this improvement is tied into the Stirling cycle and its working fluid movement. The working fluid above the power piston 12 gets shuttled between the area above and the area below the displacer piston 10 during each cycle. During the power stroke the majority of the working fluid is heated and located above the displacer piston 10 . As the power piston 12 gets pushed downward, an increase in volume occurs between the displacer piston 10 and the power piston 12 . This results in movement of the working fluid from the region above the displacer piston 10 to the region below it. With the old dead-volume system, a reservoir is connected to the flow path of the working fluid as it shuttles between those locations. The total amount of working fluid in the area above the power piston and in the dead volume does not change. Therefore, when the working fluid moves during the power stroke, part of the fluid remains in the region above the power piston and does useful work and part of the fluid expands into the dead volume chamber and does useless work. This extra quantity of wasted work reduces the total engine efficiency.
[0041] Rather than providing a dead volume on the flow path of the working fluid above the power piston, the present invention reduces the amount of working fluid present in the cylinder above the power piston 12 . On the compression stroke, until the ports are closed by the power piston the extra reservoir area volume reduces the compression and, thus, the amount of working fluid above the power piston. On the power stroke, all of the working fluid (though reduced in amount) moves to the region below the displacer piston 10 and expands against the power piston 12 doing useful work until the throttle ports open up again. A small amount of work is wasted when the throttle ports are opened by the power piston and the remaining compression is released into the reservoir area. The present invention thus reduces the amount of wasted work, thereby improving the throttle efficiency.
[0042] The descriptions above and the accompanying drawings should be interpreted in the illustrative and not the limited sense. While the invention has been disclosed in connection with the preferred embodiment or embodiments thereof, it should be understood that there may be other embodiments which fall within the scope of the invention as defined by the following claims.
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A apparatus and method for throttling a heat engine uses a plurality of cylinder ports through a side portion of the cylinder and a sleeve that selectively opens or closes them to provide fluid communication between an interior portion of the cylinder and a reservoir area when a piston in the cylinder is below the cylinder ports. The sleeve has a plurality of throttle ports through it and moves to communicate a number of the throttle ports with a number of the cylinder ports, thereby opening the cylinder ports. Cylinder ports and throttle ports may be arranged so that as the sleeve is rotated, an increasing number of cylinder ports are opened higher up the cylinder. The cylinder ports may also be arranged so that rotating the sleeve varies the amount ports are opened. The sleeve is preferably worm-gear driven for accurate position control. Upon closing the throttle, normal operating pressures are restored via use of a check valve.
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CROSS-REFERENCE TO RELATED APPLICATION(S)
This application is claims the benefit of U.S. provisional patent application No. 60/813,731, filed Jun. 13, 2006, the disclosure of which is hereby incorporated by reference in its entirety for all purposes.
BACKGROUND
The general concept of trench drains is well known in the prior art. Trench drains are generally used to transport large amounts of liquid from one location to another. Typically, trench drains are used to collect liquid runoff from residential and commercial structures and deliver the runoff to a sewer system.
Current trench drains are typically modular in design and constructed of light weight polymers, such as fiberglass reinforced polyester. Typically, the trench drains consist of channels that have two sidewalls separated by a bottom wall. To install the trench drains, a trench is typically dug to a depth twice as deep as the height of the sidewalls, such that the top of the sidewall is about ⅛″ below the surrounding surface. Modular trench drain pieces, typically in about 1 meter lengths, are connected and sealed together. Concrete is poured in the bottom of the trench, the connected trench drain pieces are placed on top, and then concrete is poured around the trench drain up to a height approximately equal to the sidewall.
Because the top of a trench drain remains level, the slope is typically built into the channel itself. To accomplish this, each section of trench drain, as the drain slopes down, has higher sidewalls than the prior, adjacent section of trench drain. Thus, many different molds are needed to cast and form construct each section of the sloping trench drain. Suppliers will also need to keep a supply of each different section of sloping channel.
SUMMARY OF THE INVENTION
In one embodiment of the invention, a modular, non-sloping section of trench drain is transformed into a sloping section of trench drain by installing sloping overlay rails. The overlay rails rest on the top of the upper edge of the sidewalls.
In another embodiment, the sloping overlay rails have a ledge which allows grating, which spans across the channel, to rest on top.
In yet another embodiment, the channels are held together and in place by a clip with a hole(s) for accepting a support rod, typically rebar, to further secure the channel in place before and after the concrete has cured.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side perspective view of a trench drain with sloping overlay rails according to one embodiment of the invention.
FIG. 2 is an end view of a trench drain with sloping overlay rails according to one embodiment of the invention.
FIG. 3 is a trench drain channel without sloping overlay rails according to one embodiment of the invention.
FIG. 4A is an overhead perspective view of the overlay rails according to one embodiment of the invention.
FIG. 4B is an overhead perspective view of an anchor clip according to one embodiment of the invention.
FIG. 5 is a side perspective view of a trench drain with sloping overlay rails and installed grating according to one embodiment of the invention.
FIG. 6 is a side perspective view of a channel bracket according to one embodiment of the invention.
FIG. 7 is an overhead perspective view of a channel bracket according to one embodiment of the invention.
FIG. 8 is and overhead view of the underside of two sections of trench drain channel joined before adding a channel bracket according to one embodiment of the invention.
FIG. 9 is an overhead view of the underside of two sections of trench drain channel joined with a channel bracket according to one embodiment of the invention.
FIGS. 10 A-D show various views of the lock device for the grates according to one embodiment of the invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
In one embodiment of the invention, a modular, non-sloping section of trench drain is transformed into a sloping section sloping trench drain by installing sloping overlay rails.
According to an embodiment of the invention, as shown in FIG. 1 , sloping overlay rails 11 , 12 are mounted on a non-sloping, modular trench drain component 13 to create a sloping trench drain 10 . As shown in FIG. 3 , the non-sloping modular trench drain component 20 , comprises sidewalls 21 spaced apart by a width W, and a bottom section 22 . Each sidewall 21 has an upper edge 24 and an inner shelf 23 below the upper edge 24 . There is also a flange with a groove 25 at one end of the modular trench drain component 20 , which flange may correspond to a “female” end and is dimensioned and adapted to receive a corresponding “male” end. The other end of the trench drain component 20 , the “male” end (not shown), is dimensioned and adapted be inserted into the “female” end, to make a tight fitting joint. In an embodiment, the joint is held together with an adhesive and is watertight. The bottom of each overlay rail 11 , 12 has an inverted U-shaped groove. As shown in FIG. 2 , each overlay rail 11 , 12 comprises an inner ledge 11 a , 12 a respectively, and an outer ledge 11 b , 12 b respectively. As shown in FIGS. 2 and 3 , the bottom of the inner ledge 11 f , 12 f rests on the top of the inner shelf 23 of the non-sloping modular trench drain component 20 .
In another embodiment, the vertical distance from the inner ledge 11 a , 12 a , to the top of the overlay rail 11 d , 12 d is constant throughout the length of the overlay rail 11 , 12 . As shown in FIG. 5 , this allows grating 31 that is level with the top rail 32 to be installed on the sloping trench drain 30 .
In an additional embodiment, as shown in FIGS. 1 and 2 , the vertical distance from 11 a , 12 a to 11 f , 12 f increases linearly from end A to end B, thereby creating the sloped trench drain 10 . For the outside of the overlay rail 11 , 12 the vertical distance from the top of the rail 11 d , 12 d to the outer ledge 11 b , 12 b increases as the slope increases, and the distance from the outer ledge 11 b , 12 b to the bottom of the outer leg 11 e , 12 e is constant. In one embodiment the rail increases in height at a rate of 0.50% to 1.00%, and in another embodiment it increases in height at a rate of about 0.75%. Thus, for a 1 meter section of trench drain having rails that increase in height at a rate of 0.75%, the increase from end A to end B would be about 0.0075 meters or about 0.295 inches. In another embodiment, fifteen different 1 meter sections of trench drain are connected together with sloping overlay rails having a 0.75% rate of increase in height, yielding a height differential of 0.1125 meters or 4.425 inches between the beginning of the first section and end of the last section. In one embodiment, the overlay rails are 1 mm shorter than the channel section to allow for some linear expansion, although a larger gap may be used.
According to one embodiment, as shown in FIG. 4A , each separate rail 41 , 42 in the matched pair 40 is a mirror image of the other. Each section of trench channel will require a different matched pair of overlay rails to create continuously sloping trench drain system. The height at the end of the overlay rail of the previous section of trench drain should correspond to the beginning height of the overlay rail of the next section of trench drain, so as to make a continuously sloping trench drain system. In another embodiment, the outside edge of each rail 41 , 42 contains four anchor lugs 44 , with center openings 45 . Each rail 41 , 42 may contain more or less than four anchor lugs 44 . The lugs 44 enhance positive anchoring during the concrete pour and the center the allows attachment of wire mesh (not shown) prior to the concrete pour. In yet another embodiment, the inside edge of each rail 41 , 42 contains two anchoring tabs 43 with a center hole 46 . Each rail 41 , 42 may contain more or less than two anchoring tabs 43 . In one embodiment, an anchoring clip 50 , as shown in FIG. 4B is inserted into an anchoring tab center hole 46 on a rail 41 and a corresponding center hole 46 on the opposite rail 42 . The anchoring clip 50 assists in maintaining a constant distance between the two separate rails 41 , 42 . Thus, neither pressure exerted inward from poured concrete, nor pressure exerted outward from the molded draft of the modular channel will significantly change the upper span between the rails 41 , 42 .
In an embodiment, as shown in FIG. 4B , the anchoring clip 50 comprises a top 47 plate with two pins 48 , and a center hole 49 . In one embodiment, the distance between the two pins 48 corresponds to the distance between the anchor tab center holes 46 , opposite each other on rails 41 , 42 . In yet another embodiment, the center hole 49 is used for a grate locking device and lines up with bolt holes 33 in the grating 31 as shown in FIG. 5 . In one embodiment, the anchoring clip 50 is inserted into corresponding holes 46 with the pins facing down. If it is desired to use a grating lock device, the anchoring clip 50 may be inserted with the pins facing up as discussed below with reference to FIGS. 10A-D .
In an embodiment, as shown in FIGS. 6-9 , different sections of the modular trench drain component are joined together with brackets to create longer sections of trench drain. Note that the sloping overlay rails are not shown in FIGS. 8 and 9 because the Figs. show the bottom portion of the trench drain system. As shown in FIG. 8 , one section of modular trench drain channel 81 is joined to another section of trench drain channel 82 . In an embodiment, trench drain channel 81 is the female end with a flange 83 , and trench drain channel 82 is the male end with securing tabs 84 . In one embodiment, trench drain channel 82 has a circular cutout 87 for a round discharge pipe (not shown).
According to one embodiment, to secure and assist in stabilizing the modular trench drain, channel brackets 60 are used as shown in FIGS. 6 and 7 . In an embodiment, the channel bracket 60 comprises a base 61 , connected to two side walls 66 , and two anchor tabs 64 on the sidewalls 66 . In one embodiment, each sidewall 66 has two grooves 62 , 63 , dimensioned to receive flanges 83 or securing tabs 84 located on modular trench channel sections as shown on FIG. 8 . In another embodiment, only a portion of each sidewall is connected to the base 61 , and one section containing one of the groves 63 is cantilevered from the base 61 . One of the grooves 62 continues from the top of the clip down through the base 61 of the clip. The other groove 63 is only present on the cantilevered portion of the sidewall that is not connected to the base 61 . In another embodiment, the anchor tabs 64 have two center holes 65 which are dimensioned to receive a piece of rebar (not shown).
In an embodiment, as shown in FIG. 9 , a channel bracket 85 is mounted over a flange (not shown) and a securing tab 84 to secure two sections of trench channel 81 , 82 together. Center holes 85 may receive rebar (not shown) to anchor the secured sections prior to pouring the concrete, as well as after the concrete has cured.
In one embodiment, as shown in FIGS. 10A-D , a locking device 100 is used to hold down slotted grates and solid covers and comprises a bolt 101 , a washer 102 , and a threaded flange 103 . In another embodiment, the flange may be used in conjunction with the anchor clip 50 shown in FIG. 4B . The anchor clip 50 would be installed with the pins facing up, and the bolt 101 with a washer 102 would be inserted through a hole in the grating, like hole 33 in FIG. 5 , and the flange 103 would be placed under the anchor clip 50 , so that the bolt 101 may be inserted into the threads 104 of the flange 103 and tightened.
Various materials may be used for the different components of the trench drain system. In one embodiment, the channel is constructed of fiberglass, polypropylene, polyethylene, polymer concrete, concrete, or combinations thereof In another embodiment, the overlay rails may be constructed of polypropylene, polyethylene, or a combination thereof. In a further embodiment, the rails are constructed of the same material as the channel, fiberglass, polymer concrete, or combinations thereof. In one embodiment, the anchor clips may be constructed of PVC, plastic, steel, aluminum, and combinations thereof. In a further embodiment, polyurethane may be used as a sealer/adhesive between the channel sections, however any commonly known sealer in the art may be used. In an embodiment, the grating lock device is constructed out of stainless steel or galvanized steal, although other materials may be used for various parts such as plastics for the flange.
While this invention has been described in connection with what are considered to be exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, dimensions, and configurations but, on the contrary, also extends to various modifications and equivalent arrangements. The invention is limited only by the claims and their equivalents.
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A modular trench drain system with sloping overlay rails. A non-sloping section of trench drain is transformed into a sloping trench drain by installing sloping overlay rails. The overlay rails rest on the top of the upper edge of the sidewalls and may have a ledge which allows grating, which spans across the channel, to rest on top. The modular channels sections may be held together and in place by a clip with holes for accepting support rods which further secure the channels in place before and after the concrete has been poured and cured around the channels.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to swimming pool vacuum cleaning devices. More particularly, the invention concerns a swimming pool vacuum cleaning apparatus having a flexible platform the central, vacuum portion of which is readily adjustable relative to the pool bottom to enable precise regulation of suction efficiency during the pool cleaning operation.
DISCUSSION OF THE INVENTION
2. Introduction
Several types of devices have been suggested for cleaning swimming pools using a suction source such as the pool circulation pump. Typically, these prior art devices include a suction head which is connected to a flexible suction line and then moved manually across the pool bottom using an elongated handle which is connected to the suction head. Devices of the aforementioned character are described in U.S. Pat. Nos. 3,805,309 issued to Levack; 4,402,101 issued to van Zyl; and 4,637,086 issued to Goode.
A drawback of many of the prior art devices resides in the fact that there is no expeditious way to regulate the suction being exerted by the device during the cleaning operation. Because the suction pressure available varies widely from pool to pool there is a real need to have a simple adjustment on the vacuum head itself to enable real time adjustment of the suction being exerted by the vacuum head without having to adjust the vacuum at the circulation pump. As will be appreciated from the discussion which follows, the apparatus of the present invention overcomes the drawbacks of the prior art by providing an adjustment on the vacuum head itself which enables the quick and easy regulation of the amount of suction being exerted by the suction head.
In the device of the preferred form of the invention, the suction adjustment is accomplished using conveniently located adjustment mechanisms provided on the top of the suction head. These adjustment mechanisms precisely regulate the spacing between the lower surface of the central, suction portion of the suction head and the bottom of the pool.
In the devices of the previously identified U.S. Pat. Nos. 4,402,101 and 4,637,086, adjustment of the spacing between the suction head and the pool bottom can be done by separately adjusting the position of each of the rollers with respect to the base or platform of the device. However, such adjustments are difficult and time consuming and are of little value to commercial pool cleaning operators who must use the vacuum head for continuous cleaning of a number of pools having suction sources of widely varying capabilities.
With respect to devices of the general character described in U.S. Pat. No. 4,637,086 wherein the individual wheel carrying axles of the wheel assemblies use movable upwardly and downwardly within slots provided in outwardly extending rib sections, the adjustment means of the present invention can frequently be added to the existing devices with relatively minor changes to the device being required. This aspect of the present invention will be discussed in greater detail in the paragraphs which follow.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a swimming pool vacuum cleaner in which the vacuum head can be readily adjusted with respect to the pool bottom so that the effective suction being exerted by the suction head can be easily regulated on a real time basis during the pool cleaning operation.
Another object of the invention is to provide a pool cleaner of the aforementioned character in which the adjustment mechanisms are conveniently located on the top of the vacuum head and can be quickly operated by hand without the need for hand tools.
Another object of the invention is to provide a pool cleaner of the character described in the preceding paragraphs in which the suction exerted by the vacuum head can be precisely regulated without the need for regulation of the remotely located suction source.
Still another object of the invention is to provide adjustment mechanisms in kit form which can be interconnected with certain types of existing, prior art pool cleaning devices without the need for major retrofit of the existing devices.
A further object of the invention is to provide an adjustment mechanism of the aforementioned character which is simple and easy to use, easy to connect to existent devices and one which can be manufactured very inexpensively.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a generally perspective view of the adjustable pool vacuum head of the present invention.
FIG. 2 is an enlarged top plan view of the apparatus of the invention.
FIG. 3 is a cross sectional view taken along lines 3--3 of FIG. 2.
FIG. 4 is a cross sectional view taken along lines 4-- 4 of FIG. 3.
FIG. 5 is a cross sectional view taken along lines 5--5 of FIG. 2.
FIG. 6 is a cross sectional view taken along lines 6--6 of FIG. 5.
FIG. 7 is a cross sectional view taken along lines 7--7 of FIG. 2.
FIG. 8 is a cross sectional view taken along lines 8--8 of FIG. 7.
FIG. 9 is a cross sectional view similar to FIG. 8, but illustrating the adjustability of the device to raise the suction portion thereof a greater distance above the bottom of the pool surface.
FIG. 10 is a cross sectional view taken along lines 10--10 of FIG. 9.
DESCRIPTION OF THE INVENTION
Referring to the drawings and particularly to FIGS. 1 through 3, the suction head assembly of the present invention comprises a generally rectangular, horizontally extending platform 12 having a central portion 14, longitudinally extending edges 16, longitudinally spaced end portions 17 and a plurality of longitudinally spaced, transverse stiffening ribs 18. The central portion of platform 12 is provided with an opening 20 and an upwardly extending cylindrical member 22 in communication with opening 20. As indicated by the phantom lines in FIGS. 1 and 7, cylindrical member 22 is adapted for interconnection with a flexible suction line which, in turn, is interconnected with a source of suction such as the pool circulation pump. A handle assembly 24 of standard construction is pivotally interconnected with platform 12 proximate the center portion 14 thereof and is used for moving the suction head across the bottom of the pool. The platform 12 and cylindrical member 22 are preferably integrally formed from a yieldably deformable plastic material.
A first, or outboard roller assembly 26 is connected to to platform 12 proximate each end portion 17 thereof. In the instant form of the invention, each outboard roller assembly 26 comprises a pair of spaced apart ribs, or walls 28, the end portions of which extend outwardly from the longitudinally extending edges 16 of the platform. As best seen in FIG. 3, each end portion of each rib member 28 is provided with a vertically extending slot 30. An axle 32 spans the adjacent walls 28 and is vertically movable within slots 30. Axles 32 function to rotatably support rollers 34, which, as shown in FIGS. 3 and 4, are adapted to engage the pool bottom B. Each axle 32 is threaded at one end to threadably receive a wing nut 36 and is provided at its other end with a head 37. By tightening and loosening wing nut 36 relative to walls 28 each axle 30 can be vertically adjusted within slots 30. In this way, the vertical height of the rollers 34 can be adjusted relative to platform 12, thereby adjusting the spacing between the pool bottom and the outboard end portions 16 of the platform 12. As will be discussed in greater detail hereinafter, adjustment of the end portions of the platform is rarely necessary because of the novel adjustability feature of the central, suction portion of the platform, the details of which will presently be described. Also, forming a part of the outboard wheel assemblies 26, is an elongated lead weight 40 and a cover 42 which is interconnected with platform 12 by a threaded connector 44 (FIG. 3).
An important aspect of the apparatus of the present invention is the second, or inboard roller assemblies 46 which are interconnected with platform 12 on either side of central opening 20. As best seen by referring to FIG. 5, the construction of the inboard roller assemblies 46 is somewhat similar to the construction of the outboard roller assemblies just described. For example, each of the outboard roller assemblies includes a weight housing having spaced apart ribs, or walls 48 (FIG. 8), each of which has an end portion 48a which extends outwardly from edges 16 of platform 12. Each end portion 48a is provided with a vertical slot 50 adapted to closely receive an axle member 52 which rotatably carries a roller 58 intermediate space member 52 which rotatably carries a roller 58 intermediate space apart end portions 48a. Each of the inboard roller assemblies 46 also includes a weight 54 and a cover 56 which is superimposed over weight 54.
A highly novel feature of the apparatus of the present invention resides in a specially configured frame member 60 which is connected to and spans platform 12 in the manner best seen in FIGS. 2 and 5. Each frame member 60 has a central portion 62 and spaced end portions 64 which extend outwardly on either side of longitudinally extending edges 16 of platform 12. As indicated in FIGS. 1 and 6, each end portion 64 of each frame member 60 includes downwardly extending, spaced apart legs 64a, each of which is provided with an aperture 68 adapted to closely receive the ends of axles 52. Legs 64a are closely receivable over walls 48 in the manner shown in FIG. 8. Frame members 60 can be constructed of metal, rigid plastic or any suitable, durable material.
The central potion 62 of each frame member 60 is provided with an aperture 70 (FIG. 8) which is adapted to closely receive a connector means, shown here as an elongate connector 72 which comprises a part of the adjustment means of the invention. As indicated in FIG. 8, connector 72 has a head portion 72a which is received in a counter bore 73 provided in platform 12 and a threaded shank portion 72b. Shank portion 72b is received through an aperture provided in each weight 54 and in each cover 56. The upper end of each connector 72 extends through the apertures 70 of the frame members 60 for interconnection with a wing nut 74 which can be threaded downwardly into engagement with the upper surface of each frame member 60 in the manner shown in FIG. 8. By tightening the wing nuts 74 against the upper surface of each frame member 60, each axle 52 will be caused to move downwardly within slots 50 from a first position shown in FIG. 5 to a second position shown in FIG. 10. This downward movement of axles 52 lowers the wheels 58 relative to platform 12 from the position shown in FIG. 8 to the position shown in FIG. 10. Lowering of wheels 58 causes an upward deformation of platform 12 in the manner shown in FIG. 9 so as to increase the spacing between the central, suction portion of the platform 12 and the pool bottom B.
Disposed intermediate the inner surface of each frame member 60 and the top surface of each cover 56 is a biasing means shown here as a coil spring 78. Coil spring 78 functions to yieldably resist downward movement of frame 60 from the position shown in FIG. 5 wherein the spring is expanded to the lowered position shown in FIG. 10 wherein the spring is compressed. It is apparent that by raising and lowering the rollers in the manner described to vary the spacing between the central, suction portion of the platform the effective suction of the device can be precisely regulated without having to adjust the suction at the suction source.
As previously mentioned another aspect of the present invention is a roller height adjustment device which can be provided in kit form for use in combination with certain types of prior art suction head assemblies. More particularly, the roller height adjustment device of the invention is usable in combination with a suction head assembly for sweeping a swimming pool using a section line connected to a source of suction of the character having a generally horizontally extending platform having a central portion longitudinally extending edges, and longitudinally spaced end portions, the end portions having an opening therethrough adapted for connection with the suction line. The suction head assembly must also have a first roller assembly connected to the platform proximate each end portion thereof with each roller assembly comprising at least two rollers adapted to maintain the end portions of the platform in a spaced relationship with respect to the bottom of the swimming pool. Finally, the suction head assembly must have a roller construction disposed on either side of the opening in the central portion of the platform with each roller construction including a housing connected to the platform having spaced apart walls including end portions having vertical slots formed therein and a pair of axles received within the vertical slots for rotatably carrying a pair of rollers for rotation about the axle between the end portions of the spaced apart walls. Preferably the roller construction of the existing suction head assembly will also have a lead weight disposed intermediate the walls of the housing, a cover member superimposed over the lead weight and a threaded connector for interconnecting the cover member with the platform of the suction head. Such a construction is shown in the right hand portion of FIG. 8 wherein the weight is designated by the numeral 40, the cover is designated by the numeral 42 and the threaded connector is designated by the numeral 44.
With a suction head assembly of the aforementioned character, the roller height adjustment device of the present invention can readily be assembled to the suction head assembly with minimum modification thereto. More particularly, the roller height adjustment device of the invention comprises a pair of frames 60 adapted to be positioned over the walls of the housing of the roller construction so as to span the platform in the manner shown in FIG. 2. Each frame 60 is of a construction previously described herein and includes transversely spaced end portions 64a each having an aperture 68 therethrough of the character shown in FIG. 6. Apertures 68 are adapted to closely receive the axles of the roller construction of the device so that an axle such as an axle 52 will extend through aperture 68 provided in frame 60 as well as through the vertical slots provided in the end portions of the spaced apart walls of the roller construction of the device. In some instances it may be necessary to replace the axles of the existing suction head with slightly longer axles.
The roller height adjustment device of the present form of the invention further comprises connector means for connecting each frame 60 to the platform of the existing device and adjustment means associated with each frame 60 for vertically adjusting the axle of each roller construction within the slots provided in the end portion of the walls of the housings of the roller constructions. In the form of the invention shown in the drawings, the connector means is provided in the form of an elongated connector such as that previously described and identified in the drawings by the numeral 72. This elongated connector includes a threaded shank portion 72 and a head portion 73. The connector is of the same general configuration as the connector used in the existing device to maintain the cover in position over the weight and the housing. However, the connector 72 is slightly longer so that the threaded upper end thereof will protrude through the central aperture provided in the frame member 60 in the manner shown in FIG. 8.
The adjustment means of this form of the invention comprises a wing nut, such as that previously described and identified by the numeral 74, which can be threadably received over the upper threaded end of the shank portion of the connector 72. The adjustment means of the invention also includes a coil spring, such as that previously identified by the numeral 60, which is adapted to be disposed intermediate the lower surface of frame 60 member and the cover 42 of the existing suction head.
The roller height adjustment device of the present invention, when sold in kit form, comprises a frame such as frame 60, an elongated connector such as connector 72, a wing nut such as wing nut 74, a coil spring such as coil spring 72 and four axles such as axles 52. Assembly of the adjustment device of the invention to an existing unit is quite simple and involves the following steps. First, the existing connector such as a connector 44 is disconnected from the closure cap which secures the weight in position within the housing of the roller construction. The cover and weight are then removed and the replacement connector element 72 is inserted through the weight in the manner shown in FIG. 8 with the head of the connector being disposed within the counter bore provided in the platform of the suction head. If necessary, the cover, such as cover 42, is then drilled out to receive the shank portion of the connector 72. Next, each of the axles of the inboard roller constructions of the existing device is removed from the vertically slotted spaced apart walls. With the axles removed and the connector element 72 in place, the coil spring is placed over the shank portion of the connector. This done, the frame 60 can be placed over the spaced apart walls, such as walls 48, so that the apertures in the downwardly extending legs thereof align with the slots in the wall portions of the existing device. As the frames 60 are implaced over the walls 48, the upper end of the connector 72 is inserted through the aperture 70 provided in the central portion of each frame 60. With the frame 60 thusly in position, each of the axles 52 can be inserted through the apertures provided in the downwardly extending leg portions of the frame member 60 and through the vertical slots provided in the side walls of the inboard roller construction of the existing device. The wing nuts 74 can then be threaded over the upper end of shank 72b, thereby completing the retrofit of the existing suction head assembly. With the frames 60 thusly positioned, precise adjustment of the inboard rollers relative to the platform can be accomplished in the manner previously described herein.
Having now described the invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difficulty in making changes and modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.
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A swimming pool vacuum cleaning apparatus having a flexible platform, including an apertured central portion adapted for interconnection with a suction line, a pair of outboard roller assemblies for maintaining the end portions of the platform in a spaced relationship with the pad bottom and a pair of inboard roller assemblies which are readily vertically adjustable relative to the platform so that the spacing between the central, suction portion of the platform and the pool bottom can be quickly and easily adjusted during the pool cleaning operation. The inboard roller assemblies as individual units can also readily be attached to certain types of existing cleaning apparatus to provide an improved vertical adjustment feature.
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FIELD OF THE INVENTION
This invention relates to a method for depositing materials on substrates and, more specifically to light controlled vapor deposition.
BACKGROUND
Coatings can be deposited on a substrate by techniques that utilize solutions, liquids, vapors, and solids as sources of the deposition materials. Deposition from the vapor phase is commonly associated with the production of a film of material. This production normally takes place on a heated substrate and in a vacuum. However, since it is frequently undesirable to significantly raise the temperature of a substrate, the high temperatures associated with vapor transport make it unsuitable for a number of applications.
Vapor deposition involves three basic steps in the formation of a coating film on a substrate: synthesis or creation of the deposition species, transport of these species from the source to the substrate, and growth of the film on the substrate. These steps can operate independently or interdependently, depending on the particular process. It is preferable to use a process where the steps operate independently, thereby allowing greater flexibility and control.
Chemical vapor deposition (CVD) is a common deposition technique. It offers good quality and excellent uniformity of the deposited film, but requires a relatively high deposition temperature.
In basic thermal chemical vapor deposition process, the reactants flow over a heated substrate surface to deposit a film. Generally the kinetics of the process are dependent on diffusion through the boundary layer between the substrate and the bulk gas-flow region. Temperatures for reactions used in CVD are usually in the range of 500°-1200° C. (930°-2200° F.).
Physical vapor deposition (PVD) is another thin film deposition technique, wherein the material to be deposited is derived from a source by physical means, and then deposited on a substrate.
The two basic processes for physical vapor deposition are: evaporation deposition and sputter deposition. In evaporation, thermal energy converts a solid or target material to the vapor phase. In sputtering, the target is based to a negative potential and bombarded by positive ions of the working gas from the plasma, which knock out the target atoms and convert them to vapor by momentum transfer.
Plasma assisted techniques are, essentially, variants of chemical and physical vapor deposition processes, which rely on the vapor transport of materials to construct new surface. Plasma assisted CVD is similar to thermal CVD with the addition of a radio-frequency biased parallel plate above the substrates. The presence of the plasma activates the deposition reaction. Various compounds are deposited by plasma-assisted chemical vapor deposition (e.g., silicon, carbon, polymers, silicon nitride, iron oxide, silicon carbide). Plasma assisted deposition techniques result in variability in the composition of the deposited species.
In physical vapor deposition, the step of transportation of the species from source to substrate may include the presence of plasma.
Most vapor deposition processes are characterized by relatively high temperature operation, which can be problematic. Plasma assisted deposition can result in undesirable space charge build-up effects. Also, in many applications, precise control of the deposited substrate is lacking with plasma assisted deposition.
It is among the objects of the present invention to provide an improved vapor deposition technique that addresses and solves these and other problems of prior art vapor deposition methods.
SUMMARY
The present invention utilizes light-induced drift (LID) to advantage in a vapor deposition process.
Light-induced drift is a kinetic effect of light based on a velocity-selective excitation and a state-dependent diffusive cross section with other species in a gas mixture. Light-induced drift and light-induced drift was predicted by Gelmukhanov and Shalagin in 1979, and has been subsequently demonstrated and studied through the 1980's.[see e.g. JEPT Lett. 29, 711 (1979), Sov. Phys. JEPT 50, 234 (1979)]]
Light-induced drift occurs when light causes a velocity-selective excitation of atoms in a gas mixture, and when the collisional interactions with other species in the gas mixture are state dependent. LID has the physical effect of causing the atoms of the selected species to drift through the gas mixture. A single mode laser commonly provides the velocity-selective excitation by tuning to one side of the Doppler absorption profile. The drift can be either positive (pushing) or negative (pulling), depending on the detuning of the light from the center of the line. Drift velocities of greater than 20 m/s have been reported in alkali-rare gas vapors. The separation effect results from an entropy exchange between the light and the gas mixture. LID is stronger than light pressure in the sense that for LID, each photon causes a change in momentum on the order of the nuclear momentum through collisions with the buffer gas, while light pressure is a direct exchange of the photon momentum, which is much smaller. Scientific applications of light-induced drift include the measurement of state-dependent diffusive cross-sections for various atoms and molecules with other species, the measurement of state-dependent wall interactions, and more recently the velocity dependence of diffusive cross sections. The cross section measurements can directly be compared with calculated values from theoretical potential curves, and therefore provide a valuable test of these potential curves. It has been suggested that LID might offer an explanation for anomalous abundances in so called peculiar stars and abundances of species in the formation of the solar system.
Although the scientific applications for light-induced kinetic effects have been quite successful, industrial applications have been slow to develop. Nearly all LID experiments have demonstrated possible applications for removing all impurities from gases. Isotope separation of molecular and atomic vapors by LID has been demonstrated. The accumulation and concentration of species by LID can also be used to measure trace abundances. Atutov (Opt. Commun. 83, 307-309 (1991)) has demonstrated density enhancements of 10 3 , and much greater enhancements are possible. 10.sup.
One important quality of LID is the ability to control the bulk motion of the atoms easily with externally applied light beams.
Applicant provides a method for depositing a material on a substrate surface utilizing LID by selectively pulling the atoms of a material through a buffer gas and onto a target substrate surface. Applicant also provides a method whereby LID is used to push atoms away from selected areas on a substrate surface. This results in ordinary diffusive deposition in areas of no light, with no deposition where the field is present.
A primary benefit of applicant's method is the ability to draw or push a vapor through a cold buffer gas, allowing a gentle low temperature coating on sensitive surfaces. Additionally, the deposited atoms are electrically neutral, eliminating space charge buildup effects associated with plasma deposition.
An important feature of applicant's deposition technique is that the deposition can be controlled by light. Layers can be "written" onto the surface by controlling the position, frequency, and intensity of the laser beam. The LID process is also species and isotopive selective. It is envisioned that several species in a vapor could be deposited in succession from a single mixture. Additionally, the species selectivity could also be employed to push away unwanted impurities from an industrial process. An example might be to force a reactive species such as neutral fluorine onto a surface for etching in semiconductor productions.
Applicant's LID vapor deposition is diffusive in nature, eliminating shadowing effects that occur in direct vacuum deposition. Additionally, Applicant's method results in uniform deposition over convoluted surfaces, and for making good electrical contact between the film and metal terminal strips.
Further features and advantages of the invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of an apparatus that can be used in practicing an embodiment of the invention.
FIG. 2 is another diagram of an apparatus that can be used in practicing an embodiment of the invention.
FIG. 3 is a graph depicting thickness of deposited film vs. horizontal position after 15 min. exposure where the buffer gas pressure is 50 Torr (Ar).
FIG. 4 is a graph depicting thickness of deposited film vs. horizontal position after three time exposures where the buffer gas pressure is 50 Torr (Ar).
DETAILED DESCRIPTION
An embodiment of Applicant's invention is illustrated in conjunction with FIG. 1, which shows a diagram for vapor deposition in a chamber (not shown) containing a buffer gas, such as argon, at controlled pressure. In this particular embodiment, light is emitted from a single-mode Ti: sapphire cw ring laser (not shown), detuned 0.5 GHz to blue from the fluorescence maximum of potassium D 1 resonance at 769.9 nm. The lens 2 is a 25 mm focal length convex lens placed so that it is just inside the glass window 3. The container is a borosilicalite glass tube containing a few mg of potassium and wrapped with heat tape 4. At 150° C., the estimated potassium number density under the heat tape is 10 13 cm 3 . As the layer is detuned from resonance, target atoms are drawn by LID from the heated region in the direction opposite to the light propagation. The atoms drift through the buffer (cooling to the local buffer gas temperature in the process) until they are deposited on the glass substrate 3.
The potassium film thickness is determined from transmission measurements of collimated, incandescent light which has been passed through λ 0 =760 nm narrow bandpass. Incoherent light is preferred over laser light for this purpose of measurement, to minimize undesirable interference effects.
FIGS. 3 and 4 illustrate the results of two pulling experiments at different buffer gas pressures. FIG. 3 shows a cross section layer deposited after 15 minutes with 50 Torr argon, while FIG. 4 shows the development of a layer deposited with 5 Torr argon. In both instances the focused spot was much less than 1 mm in diameter at the substrate and the effect of diffusive "feathering" out from the laser spot is clearly visible. FIGS. 3 and 4 demonstrate an increased resolution with higher buffer gas pressures. This is expected because the reduced mean free path slows the diffusion of potassium atoms out of the laser beam. The drift slows as well due to a decrease in the velocity selectivity of the excitation. The resolution, however, depends on the relative strength of the LID transport compared to the diffusive transport, and increases at higher pressure. As the buffer gas pressure is lowered, the volume of potassium delivered to the substrate is much larger. This is achieved, however, at the expense of spatial resolution. There is also a point which the pressure is so low that regular diffusion contributes substantially to film growth and spatial resolution is essentially lost. In experiments with potassium in argon, this occurred at roughly 1 Torr. One obvious problem with this pulling method of deposition is that the light controlling the process must pass through an absorbing layer of the chemical which it has just helped to deposit. This can lead to heating and burn off at the focal point of the laser light, and general slowing of the deposition rate. This is the central dip observed in FIGS. 3 and 4. The burned hole can be eliminated by focusing further behind the surface and/or actively cooling the substrate cool air can be blown on the substrate to keep it at room temperature.
It is important to impart to the target atoms a velocity component directed towards the center line of the light cone by wave-front curvature in order to collect the atoms into a high density region before they are deposited onto the substrate. This was demonstrated by replacing the 25 mm FL lens with a 270 mm FL lens and observing that no film deposit whatsoever with 50 Torr argon after 15 min. The wave front curvature could also improve the resolution by countering diffusion out of the beam near the substrate.
The use of light induced drift to prevent vapor deposition of target atoms onto a substrate in designated areas is shown in FIG. 2. The lens 4 is placed all the way up to the window 3, and a mask (not shown) is placed over the window with a cut-out rectangle area of 6.8 mm 2 . The collimated beam 8 fills the square beam with sharp edges enters the vapor. The laser is then detuned from resonance to push the target atoms way from the window, so that as the cell is heated, potassium atoms will vapor deposit everywhere except where they interact with light. Using a 1 torr argon and 320 mW total laser power resulted in an area slightly larger than the square remaining clear of the deposited film. Subsequent experiments revealed that a balance between buffer gas pressure and laser intensity is required to maximize the spatial resolution of the image, and a sharp square was obtained with 1 Torr Argon and 35 Mw total power after the masks. The edge resolution of the coated square was 100 μm.
The invention has been described with reference to particular preferred embodiments, but variation within the spirit and the scope of the invention will occur to those skilled in the art. For example, while a single light beam was illustrated for implementing LID, it will be understood that more than one beam can be utilized. The beams can be controlled independently or together. Further an interference pattern or hologram could be established on a surface or surfaces where deposition is to be controlled.
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A method is disclosed for depositing a substance on a substrate, including the following steps: providing the substrate in a deposition chamber, providing in the chamber a vapor of the substance, providing a buffer gas in the chamber, and directing a light beam at the substrate to control deposition of the substance by causing light induced drift.
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FIELD OF THE INVENTION
The present invention generally relates to techniques for monitoring and controlling continuous sheetmaking systems such as a papermaking machine and more, specifically to maintaining proper cross-directional alignment in sheetmaking systems by extracting alignment information from a closed-loop CD control system.
BACKGROUND OF THE INVENTION
In the art of making paper with modern high-speed machines, sheet properties must be continually monitored and controlled to assure sheet quality and to minimize the amount of finished product that is rejected when there is an upset in the manufacturing process. The sheet variables that arc most often measured include basis weight, moisture content, and caliper (i.e., thickness) of the sheets at various stages in the manufacturing process. These process variables are typically controlled by, for example, adjusting the feedstock supply rate at the beginning of the process, regulating the amount of steam applied to the paper near the middle of the process, or varying the nip pressure between calendaring rollers at the end of the process. Papermaking devices are well known in the art and are described, for example, in “Handbook for Pulp & Paper Technologists” 2nd ed., G. A. Smook, 1992, Angus Wilde Publications, Inc., and “Pulp and Paper Manufacture” Vol 111 (Papermaking and Paperboard Making), R. MacDonald, ed. 1970, McGraw Hill. Sheetmaking systems are further described, for example, in U.S. Pat Nos. 5,539,634 to He, 5,022,966 to Hu, 4,982,334 to Balakrisbnan, 4,786,817 to Boissevain et al, and 4,767,935 to Anderson et at. Process control techniques for papermaking machines are further described, for instance, in U.S. Pat Nos. 6,149,770 to Hu et al., 6,092,003 to Hagart-Alexander et. al, 6,080,278 to Heaven et al., 6,059,931 to Hu et al., 5,853,543 to Hu et al., and 5,892,679 to He.
On-line measurements of sheet properties can be made in both the machine direction and in the cross direction. In the sheetmaking art, the term machine direction (MD) refers to the direction that the sheet material travels during the manufacturing process, while the term cross direction (CD) refers to the direction across the width of the sheet which is perpendicular to the machine direction.
Papermaking machines typically have several control stages with numerous, independently-controllable actuators that extend across the width of the sheet at each control stage. For example, a papermaking machine will typically include a headbox having a plurality of slice lip force actuators at the front which allow the stock in the headbox to flow out on the fabric of the web or wire. The papermaking machine might also include a steam box having numerous steam actuators that control the amount of heat applied to several zones across the sheet. Similarly, in a calendaring stage, a segmented calendaring roller can have several actuators for controlling the nip pressure applied between the rollers at various zones across the sheet.
All of the actuators in a stage are operated to maintain a uniform and high quality finished product. Such control might be performed, for instance, by an operator who periodically monitors sensor readings and then manually adjusts each of the actuators until the desired output readings are produced. Papermaking machines can further include computer control systems for automatically adjusting cross-directional actuators using signals sent from scanning sensors.
In making paper, virtually all MD variations can be traced back to high-frequency or low-frequency pulsations in the headbox approach system. CD variations are more complex. Preferably, the cross-directional dry weight profile of the final paper product is flat, that is, the product exhibits no CD variation, however, this is seldom the case. Various factors contribute to the non-uniform CD profiles such as non-uniformities in pulp stock distribution, drainage, drying and mechanical forces on the sheet. The causes of these factors include, for example, (i) non-uniform headbox delivery, (ii) clogging of the plastic mesh fabric of the wire, (iii) varying amounts of tension on the wire, (iv) uneven vacuum distribution, (v) uneven press or calendar nip pressures, and (vi) uneven temperatures and airflows across the CD that lead to moisture non-uniformities.
Cross-directional measurements are typically made with a scanning sensor that periodically traverses back and forth across the width of the sheet material. The objective of scanning across the sheet is to measure the variability of the sheet in both CD and MD. Based on the measurements, corrections to the process are commanded by the control computer and executed by the actuators to make the sheet more uniform.
In practice, control devices that are associated with sheetmaking machines normally include a series of actuator systems arranged in the cross direction. For example, in a typical headbox, the control device is a flexible member or slice lip that extends laterally across a small gap at the bottom discharge port of the headbox. The slice lip is movable for adjusting the area of the gap and, hence, for adjusting the rate at which feedstock is discharged from the headbox. A typical slice lip is operated by a number of actuator systems, or cells, that operate to cause localized bending of the slice lip at spaced apart locations in the cross-direction. The localized bending of the slice lip member, in turn, determines the width of the feed gap at the various slice locations across the web.
It is standard practice that sheetmaking machines be controlled by adjusting actuators using measurement signals provided by scanning sensors. In the case of cross-directional control, for example, a commonly suggested control scheme is to measure values at selected cross direction locations on a sheet and then to compare those measured values to target or set point values. The difference for each pair of measured and set point values, i.e., the error, can be used for algorithmically generating appropriate outputs to cross direction control actuators to minimize the error. In such systems, a measurement zone is defined as the cross direction portion of sheet which is measured and used as feedback control for a cross direction actuator zone, and a control zone is defined as the portion of the sheet affected by a cross direction actuator zone.
In practice, it is difficult to control sheetmaking machines by adjusting actuators using measurement signals provided by scanning sensors. The difficulties particularly arise because the scanning sensors are separated from the control actuators by substantial distances in the machine direction. Because of such separations, it is difficult to determine which measurements zones are associated with which actuator zones. Such difficulties are referred to as alignment problems in the papermaking art. Alignment problems are exacerbated when, as is typical, there is uneven paper shrinkage of a paper web as it progresses through a papermaking process. Another difficulty is that the effect of each actuator is not always limited within the corresponding control zone but spans over a few control zones. Alignment is an important process model parameter for keeping the CD control system stable and operating. The alignment can change over time and subsequently degrade the controller performance and thus paper quality.
One conventional method for aligning actuator zones with measurement zones involves the use of dye tests. In a dye test, narrow streams of colored liquid are applied to feedstock as it flows beneath a slice lip. The dye streams initially form parallel lines that extend in the machine direction, but those lines may deviate from parallel if there is web shrinkage during the papermaking process. The dye marks passing through the measurement devices reveal the distribution of control zones and therefore specify the alignment of measurement zones.
Conventional dye tests, however, have numerous drawbacks. The most serious drawback is that the tests destroy finished product and, therefore, it is seldom feasible to perform dye tests at an intermediate point in a sheetmaking production run, even though sheetmaking processes are likely to drift out of control during such times. Further, because of the limited thickness and high absorption characteristics of tissue grades of paper, dye tests are typically limited to paper products that have relatively high weight grades.
More recently, systems that automatically and non-destructively map and align actuator zones to measurements zones in sheetmaking systems have been developed. Some of these systems perform so-called “bump tests” by disturbing selected actuators and detecting their responses, typically with the CD control system in open-loop. The term “bump test” refers to a procedure whereby an operating parameter on the sheetmaking system, such as a papermaking machine, is altered and changes of certain dependent variables resulting therefrom are measured. Prior to initiating any bump test, the papermaking machine is first operated at predetermined baseline conditions. By “baseline conditions” is meant those operating conditions whereby the machine produces paper of acceptable quality. Typically, the baseline conditions will correspond to standard or optimized parameters for papermaking. Given the expense involved in operating the machine, extreme conditions that may produce defective, non-useable paper are to be avoided. In a similar vein, when an operating parameter in the system is modified for the bump test, the change should not be so drastic as to damage the machine or produce defective paper. After the machine has reached steady state or stable operations, the certain operating parameters are measured and recorded. Sufficient number of measurements over a length of time is taken to provide representative data of the responses to the bump test.
The standard bump test for CD model identification includes the following steps: (1) placing a control system in open-loop; (2) bumping a subset of the actuators at the headbox to follow a step or series of steps in time; (3) collecting the output data as measured by sensor(s) in the scanner; and (4) running a model identification algorithm to identify the model parameters including alignment.
For example, U.S. Pat. No. 5,400,258 to He discloses a standard alignment bump test for a papermaking system in which an actuator is moved and its response is read by a scanning sensor and the alignment is identified by the software. U.S. Pat. No. 6,086,237 to Gorinevsky and Heaven discloses a similar technique but with more sophisticated data processing. Specifically, in their bump test the actuators are moved and technique identifies the response as seen by the scanner.
With current bump test alignment methods, the operator can identify the alignment at the time of the bump test experiment. To track alignment changes over time there is a need to re-identify alignment over the course of days and weeks. Moreover, model identification for a system in closed-loop control is well known to be challenging. This is due in part to the fundamental reason that a closed-loop control system works to eliminate any perturbations, so prior art techniques have endeavored to “sneak” a perturbation into the actuator profile that works against the rest of the system and attaining sufficient excitation of the system is difficult to achieve.
SUMMARY OF THE INVENTION
The present invention provides a novel method for identifying the alignment of a sheetmaking system while the system remains in closed-loop control. In contrast to the standard model identification techniques that are employed in conjunction with an open or closed-loop control system, the invention exploits the closed-loop control to its advantage. The technique can include the following steps: (1) leaving the control system in closed-loop, (2) artificially inserting a step signal on top of the measurement profile from the scanner (equivalently, inserting a step signal on top of a setpoint target profile), (3) recording the data as the control system moves the actuators to remove the perceived disturbance, and (4) refining or developing a model from the artificial measurement disturbance to the actuator profile.
The invention is based in part on the recognition that steady-state response of the actuator profile contains information from which the sheetmaking system alignment can be extracted.
In one embodiment, the invention is directed to a method for alignment of a sheetmaking system having a plurality of actuators arranged in the cross-direction wherein the system includes a control loop for adjusting output from the plurality of actuators in response to sheet profile measurements that are made downstream from the plurality of actuators, the method including the steps of:
(a) determining alignment information from at least two cross-directional positions by: (i) operating the system and measuring a profile of the sheet along the cross-direction of the sheet downstream from the plurality of actuators and generating a profile signal that is proportional to a measurement profile; (ii) adding a perturbative signal to the measurement profile (equivalently, adding a perturbative signal to a setpoint target profile) to generate a modified profile signal that simulates a disturbance (equivalently, a setpoint change) at a position along the measurement profile; (iii) determining alignment shift information based on the closed-loop response of the actuator profile to the modified profile signal (or setpoint change); and (iv) repeating steps (i) through (iii) wherein step (ii) comprises adding a perturbative signal to the measurement profile (equivalently, adding a perturbative signal to a setpoint profile) to generate a modified profile signal that simulates a disturbance (equivalently, a setpoint change) at a different position along the measurement profile thereby obtaining alignment shift information from at least two cross-directional positions; (b) identify the changes in alignment of the sheetmaking system, if any, from the alignment shift information from at least two cross-directional positions.
In another embodiment, the invention is directed to method for extracting cross-directional information from a sheetmaking system having a plurality of actuators arranged in the cross-direction wherein the system includes a control loop for adjusting output from the plurality of actuators in response to sheet profile measurements that are made downstream from the plurality of actuators, the method including the steps of:
(a) operating the system and measuring a profile of the sheet along the cross-direction of the sheet downstream from the plurality of actuators and generating a profile signal that is proportional to a measurement profile; (b) adding a perturbative signal to the measurement profile (equivalently, adding a perturbative signal to a setpoint target profile) to generate a modified profile signal that simulates a disturbance (equivalently, a setpoint change) of at least one position along the measurement profile; and (c) determining cross-directional alignment information based on actuator responses to the modified profile signal.
In a further embodiment, the invention is directed to a system for alignment of a sheetmaking system having a plurality of actuators arranged in the cross-direction wherein the system includes a control loop for adjusting output from the plurality of actuators in response to sheet profile measurements that are made downstream from the plurality of actuators, the system comprising:
(a) means for determining alignment information from at least two cross-directional positions that includes: (i) means for measuring a profile of the sheet along the cross-direction of the sheet downstream from the plurality of actuators; (ii) generating a profile signal that is proportional to a measurement profile; (iii) means for adding a perturbative signal to the measurement profile (equivalently, adding a perturbative signal to a setpoint target profile) to generate a modified profile signal that simulates a disturbance (equivalently, a setpoint change) at a position along the measurement profile; and (iv) means for determining alignment shift information based on the closed-loop response of the actuator profile to the modified profile signal; and (b) means for identifying the changes in alignment of the sheetmaking system, if any, from the alignment shift information from at least two cross-directional positions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 , 2 , and 3 are schematic illustrations of a papermaking system;
FIG. 4 is a block diagram of a sheetmaking system with the inventive reverse closed-loop bump test;
FIGS. 5A , 5 B, and 5 C are the setpoint target, actuator and measurement profiles vs. CD position, respectively, in a normal steady-state closed-loop operation;
FIG. 6A shows the setpoint target that is modified with “bumps” at ¼ (low side) and ¾ (high side) across the paper, and FIGS. 6B and 6C show the actuator and measurement profiles vs. CD positions, respectively, in a closed loop steady-state operation with setpoint target bumps;
FIGS. 7A , 7 B, and 7 C show the difference between the closed-loop profiles representing normal steady-state closed loop operation in FIGS. 5A , 5 B, and 5 C and the closed-loop steady-state profile with setpoint target bumps of FIGS. 6A , 6 B, and 6 C;
FIGS. 8A and 8C are the graphs of gain vs. frequency of the low side and high side actuator responses to reverse bump tests, respectively;
FIGS. 8B and 8D are the graph of low-frequency phase vs. frequency of the low side and high side actuator responses; and
For FIG. 9 , the asterisks plot the slopes of the zero frequency phases illustrated in FIGS. 8B and 8D vs. CD positions of the induced setpoint target bumps that are positioned approximately ¼ and ¾ of the way across the paper; the straight line in FIG. 9 is a straight line fit between these two data appoints.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
As shown in FIG. 1 , a system for producing continuous sheet material includes various processing stages such as headbox 10 , steambox 12 , a calendaring stack 14 and reel 16 . The array of actuators 18 in headbox 10 controls the discharge of wet stock (or feedstock) material through a plurality of slices onto supporting web or wire 30 which rotates between rollers 22 and 24 . Similarly, actuators 20 on steambox 12 can control the amount of steam that is injected at points across the moving sheet. Sheet material exiting the wire 30 passes through a dryer 34 which includes actuators 36 that can vary the cross directional temperature of the dryer. A scanning sensor 38 , which is supported on supporting frame 40 , continuously traverses and measures properties of the finished sheet in the cross direction. Scanning sensors are known in the art and are described, for example, in U.S. Pat. No. 5,094,535 to Dalquist, U.S. Pat. No. 4,879,471 to Dalquist, et al, U.S. Pat. No. 5,315,124 to Goss, et al, and U.S. Pat. No. 5,432,353 to Goss et al, which are incorporated herein. The finished sheet product 42 is then collected on reel 16 . As used herein, the “wet end” portion of the system includes the headbox, the web, and those sections just before the dryer, and the “dry end” comprises the sections that are downstream from the dryer. Typically, the two edges of the wire in the cross direction are designated “front” and “back” (alternatively, referred as the “high and ‘low”) with the back side being adjacent to other machinery and less accessible than the front side.
The system further includes a profile analyzer 44 that is connected, for example, to scanning sensor 38 and actuators 18 , 20 , 32 and 36 on the headbox 10 , steam box 12 , vacuum boxes 28 , and dryer 34 , respectively. The profile analyzer is a computer which includes a control system that operates in response to the cross-directional measurements from scanner sensor 38 . In operation, scanning sensor 38 provides the analyzer 44 with signals that are indicative of the magnitude of a measured sheet property, e.g., caliper, dry basis weight, gloss or moisture, at various cross-directional measurement points. The analyzer 44 also includes software for controlling the operation of various components of the sheetmaking system, including, for example, the above described actuators.
FIG. 2 depicts a slice lip control system which is mounted on a headbox 10 for controlling the extent to which a flexible slice lip member 46 extends across the discharge gap 48 at the base of the headbox 10 . The slice lip member 46 extends along the headbox 10 across the entire width of the web in the cross-direction. The actuator 18 controls of the slice lip member 46 , but it should be understood that the individual actuators 18 are independently operable. The spacing between the individual actuators in the actuator array may or may not be uniform. Wetstock 50 is supported on wire 30 which rotates by the action of rollers 22 and 24 .
As an example shown in FIG. 3 , the amount of feedstock that is discharged through the gap between the slice lip member and the surface of the web 30 of any given actuator is adjustable by controlling the individual actuator 18 . The feed flow rates through the gaps ultimately affect the properties of the finished sheet material, i.e., the paper 42 . Specifically, as illustrated, a plurality of actuators 18 extend in the cross direction over web 30 that is moving in the machine direction indicated by arrow 6 . Actuators 18 can be manipulated to control sheet parameters in the cross direction. A scanning device 38 is located downstream from the actuators and it measures one or more the properties of the sheet. In this example, several actuators 18 are displaced as indicated by arrows 4 and the resulting changes in sheet property is detected by scanner 38 as indicated by the scanner profile 54 . By averaging many scans of the sheet, the peaks of profile 54 indicated by arrows 56 can be determined. This type of operation is typically used in traditional open and closed-loop bump tests. In contrast, the inventive reverse bump test does not directly send perturbations to the actuator profile. It should be noted that besides being positioned in the headbox, actuators can be placed at one or more strategic locations in the papermaking machine including, for example, in the steamboxes, dryers, and vacuum boxes. The actuators are preferably positioned along the CD at each location.
FIG. 4 illustrates an embodiment the closed-loop reverse bump test for a sheetmaking system such as that shown in FIG. 1 . The term “reverse bump test” denotes that in contrast to standard model identification techniques that perturb one or more actuators and then extract information from the response, e.g., measurement profile from the scanner, the inventive technique artificially inserts a step signal d y on top of the measurement profile y (equivalently, a step signal d r on top of the setpoint target profile r) and then analyzes the actuator response while the system is under closed-loop control.
Referring to FIG. 4 , the process employs a controller denoted by K for use with a profile analyzer for the sheetmaking system denoted G. Signals associated with this process include r, u, and y. The r signal represents a selected target or selected setpoint level, signal u represents the actuator signal, and signal y represents the measurement profile, e.g., scanner measurements. When controlling and measuring sheetmaking parameters in the cross direction, it is understood that the signals will be arrays or vectors, so that, for instance, y can be described as a vector whose ith component is the weight level or moisture level or thickness of a sheet at the ith position along a scanner. The signal d y represents an unmeasured disturbance or a perturbation or offset signal that is inserted in the measurement profile. The signal d r represents a perturbation or offset signal that is inserted on the target profile. The controller K can be any suitable closed-loop controller and may contain many signal processing components, for example, spatial and/or temporal filters, a proportional integral derivative (PID) controller, Dahlin controller, proportional plus integral (PI) controller, or proportional plus derivative (PD) controller, or a model predictive controller (MPC). An MPC is described in U.S. Pat. No. 6,807,510 to Backstrom and He, which is incorporated herein by reference. During normal production, a y signal profile is continuously generated by scanning the finished paper product and this signal is compared to the r signal for any error defined by e=r−y when d r =0 .
The inventive closed-loop reverse bump test can be implemented to generate alignment data for any of the actuators that control cross direction operations of the various components for the sheetmaking system shown in FIG. 1 provided that the actuators are connected to the perturbed profile measurement y, setpoint r, or error e in the closed-loop through controller K. Therefore, while the invention will be illustrated by monitoring the actuators at the headbox which control that feedstock discharge through the individual slices, the invention can also be implemented to ascertain alignment data for any of the actuators that control cross directional unit operations in the sheetmaking machine including, for example, the steambox, dryer, and vacuum box.
In implementing the reverse bump test, a sheetmaking system G, such as a papermaking machine, is initially operated with actuators that are set by the feedback controller K to cause y to match a target signal profile r as closely as possible. During paper production, a y signal profile is generated by scanning the finished paper product. Thereafter, with the papermaking machine still in closed-loop control, the target profile is modified by inserting a pertubative signal d r to create a setpoint target profile at summer 64 of r+d r . The measurement profile y signal profile from the scanner will be subtracted from the setpoint target profile at summer 62 . Controller K will convert the error signal e from the comparator into an actuator signal profile u that is received by the papermaking machine. The effect will be that the papermaking machine feedstock discharge through the slice lip opening at the headbox that will be adjusted to have the measurement profile y follow the perceived change in setpoint target.
The following describes a preferred technique of implementing the inventive reverse bump test for closed-loop identification of CD controller alignment. In operation, the control system of the papermaking machine, for instance, is left in the closed-loop and a step signal is artificially inserted on top of the measurement profile from the scanner which measures the finished paper product. Data is recorded as the control system responds by adjusting the actuators at the headbox to remove the perceived perturbation. Finally, a model, which contains alignment information, is identified from the data comprising the artificial measurement disturbance and the resulting actuator profile. In actual implementation of the reverse bump test, the “bump” should not be so drastic as to cause the final product, e.g., paper, to be unfit for sale.
Reverse Bump Test Design And Data Collection Procedure
(1) Design a bump test by designing the setpoint target bumps (δr).
a. Using a papermaking machine for illustrative purposes, preferably at least two well-separated “bump” are positioned in the cross-direction. For example, they can be located at ¼ and ¾ across the sheet width.
b. In the time domain, operate the machine at a baseline and then operate the machine in a plurality of steps up and down. The simplest technique is to execute a single step that lasts long enough for the closed-loop controller to reach its new steady state with the setpoint bumps.
(2) Run the reverse bump test. With the CD in closed-loop control, modify the setpoint target profile with (r+δr) as designed above. While logging the data for:
a. Two dimensional setpoint target array (r).
b. Two dimensional setpoint target bumps (δr).
c. Two dimensional scanner profile measurements (y).
d. Two dimensional actuator profile array (u).
To illustrate the utility of the inventive technique, computer simulations implementing the reverse bump test for closed-loop identification were conducted using Matlab R12 software from Mathworks. The simulations modeled a papermaking machine as depicted in FIG. 4 with a headbox having 45 actuators that controlled pulp stock discharge through the corresponding slice lip opening. The weight of the finished paper was measured by a scanner at 250 points or bins across the width of the paper from the front to back side of the machine; each bin represents a distance of about 5 mm. The weight of the finished paper had a mean value of about 191 lb per 1000 units of sheet. The model also simulated closed-loop control of the actuators in response to signals from the scanner.
FIGS. 5A and 5C show the setpoint target and measurement profiles for paper vs. CD position in a normal steady-state closed loop operation. As is apparent, the setpoint target and measurement profiles for the finished paper are essentially the same and are represented by horizontal profiles depicting paper that has a weight of slightly more than 191 lb per 1000 units of sheet. Note that an actual papermaking machine would typically not have such a flat measurement profile y as there are typically uncontrollable high spatial frequency components that are not removed by the controller and do not affect this analysis. FIG. 5B is the headbox actuator profile and shows how the flow of pulp through the slices in the headbox varies across the headbox. The change in actuator response is relative to a baseline of zero. These profiles illustrate the appearance of the cross-directional control system prior to performing the “reverse bump test” experiment.
FIGS. 6A and 6C show the setpoint target and measurement profiles for paper vs. CD position in a steady-state closed loop operation after the setpoint target has been modified with ‘bumps’ at ¼ and ¾ across the paper sheet. As is apparent, the modifying setpoint target causes a corresponding change in the measurement profile for the finished paper. FIG. 6B is the headbox actuator profile and shows the slice jack actuator positions across the headbox. These profiles illustrate the appearance of the cross-directional control system during the “reverse bump test” experiment once the closed-loop has reached the steady-state.
Alignment Identification Algorithm
a. Using standard techniques, the response of the actuator profile to the setpoint target bumps is computed. In one preferred method, the actuator profile can be computed as the difference between the baseline actuator profile (prior to bumps) and the steady-state actuator profile (after bumps are inserted). As an illustration, FIGS. 7A , 7 B, and 7 C are the difference between the closed-loop target setpoint, actuator and measurement profiles. The actuator array illustrated is denoted as u resp . Specifically, the actuator profile plotted in FIG. 7B was computed by subtracting the normal operation closed-loop actuator profile in FIG. 5B from the closed-loop actuator profile resulting from the setpoint target bumps in FIG. 6B ,
u resp =u bump −u normal
The 1-dimensional array profiles u normal and u bump are the best estimates of the actuator profile during the baseline collection and the actuator profile for the system having reached steady-state after the bumps.
b. Next the actuator response profile and the setpoint target bump profile (as illustrated in the graphs in FIGS. 7B and 7A ) are partitioned. in the middle to make two arrays of approximately equal length:
u
resp
=
[
u
low
u
high
]
δ
r
=
[
δ
r
low
δ
r
high
]
c. Compute the Fourier transforms of each of the component arrays:
U low ƒ =ƒƒt ( u low ) δ R low ƒ =ƒƒt (δƒ low )
U high ƒ =ƒƒt ( u high ) δ R high ƒ =ƒƒt (δƒ high )
d. Now the closed-loop spatial frequency response of the low end of the sheet and the high end of the sheet may be given by:
T low ƒ =U low ƒ ./δR low ƒ
T high ƒ =U high ƒ ./δR high ƒ
where “./” denotes element-by-element division.
e. For CD control systems, the low-frequency components of the arrays T low ƒ , and T high ƒ will be equal to the inverse of the frequency response of the process itself, as practical cross-directional control will eliminate all low spatial frequency components of the steady-state error profile e=r−y, thus meaning that the actuator profile u contains exactly the correct alignment at low spatial frequencies. Thus the low frequency phase information in the arrays T low ƒ and T high ƒ will contain the true alignment information of the system.
e. The phase information of phase(T low ƒ ) and phase(T high ƒ ) could potentially be used directly. Alternatively, as illustrated here, the possibility of using the reverse bump test to compute the alignment change between two reverse bump tests that are performed perhaps days/weeks/months apart was considered. In this case, the alignment change between the alignment at the time of an “old” reverse relative to the alignment at the time of a “new” reverse bump test is computed, as follows:
H low ƒ =U low ƒ (new)./ U low ƒ (old)
H high ƒ =U high ƒ (new)./ U high ƒ (old)
then the phase information phase(H low ƒ ) and phase(H high ƒ ) are plotted with respect to the spatial frequency v as shown in FIGS. 8B and 8D , respectively.
g. A straight line through the low frequency components of phase(H low ƒ ) and phase(H high ƒ ) is fitted through the low frequency components of the two plots of FIGS. 8B and 8D , respectively. For the example illustrated in FIG. 8 , the low side phase ( FIG. 8B ) has a slope of 29.5 engineering units at zero frequency. Since the simulation used millimeters, the slope is 29.5 mm). The high side phase ( FIG. 8D ) has a slope of 50.9 mm at zero frequency. The y-axis intercepts of these straight lines should naturally be zero (and this can be constrained during the curve fit). The slope of this straight line is equal to the change in the alignment of the paper sheet at the CD positions of the low bump and the high bump, respectively.
h. Since it was assumed the change in alignment to be linear, the fact that at least two well-spaced bumps were employed allowed the two slopes to determine the two degrees of freedom assumed for the linear change in alignment. A straight line is drawn between the two measured points in FIG. 9 to model the change in alignment for the overall sheet as a function of the cross-directional position. Specifically, in FIG. 9 , the slopes of the zero frequency phases illustrated in FIG. 8 , i.e., 29.5 mm and 50.9 mm, were plotted against the CD position of the induced setpoint target bumps (δr) which are positioned approximately ¼ and ¾ of the way across the sheet as described above. It was assumed that the change in alignment was linear across the sheet width. The line in the graph is an alignment update computed from a linear fit between the two data points computed from the data obtained during the reversed bump test. A linear alignment shift is the most common experienced on actual papermaking machines. As is evident, other models of alignment can be accommodated and would simply involve a different distribution of the induced setpoint target bumps (δr).
If a more complicated nonlinear shrinkage pattern is assumed, then the above procedure could be modified to identify the nonlinear alignment change. This can be accomplished by designing more than two well-spaced bumps. This could potentially require the bumps to be staggered in time. For example, the bumps can be implemented sequentially. Finally, the change in cross-directional controller alignment as a function of cross-directional position on the sheet has been computed. e.g., as illustrated in FIG. 9 . This function can then be used to update the alignment of the online cross-directional controller. A CD control system will perform at its best when the controller alignment matches the true alignment of the paper sheet and the actuators.
The foregoing has described the principles, preferred embodiment and modes of operation of the present invention. However, the invention should not be construed as limited to the particular embodiments discussed. Instead, the above-described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of present invention as defined by the following claims.
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A reverse bump test, for identifying the alignment of a sheetmaking system while the system remains in closed-loop control, includes the following steps: (a) leaving the control system in closed-loop, (b) artificially inserting a step signal on top of the measurement (or setpoint) profile from the scanner, (c) recording the data as the control system moves the actuators to remove the perceived disturbance (or setpoint change), and (d) refining or developing a model from the artificial measurement disturbance (or setpoint change) to the actuator profile. The technique supplies the probing/perturbation signal to the scanner measurement, which is equivalent to supplying the probing/perturbation signal to the setpoint target) rather than inserting bumps via the actuator set points as has been practiced traditionally.
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BACKGROUND OF THE INVENTION
The present invention relates generally to hydraulic positioning and control systems and, more particularly, to positioning and control systems for thrust reverser cowls of turbofan jet engines.
High bypass turbofan jet engines of the type used on large commercial airplanes include a large rotatable turbofan coupled to the forward end of the central shaft of a turbine jet engine. The diameter of the turbofan is considerably greater than that of the jet engine immediately behind it. Rotation of the turbofan by the turbine engine causes the turbofan to produce a fan thrust by blowing air rearwardly around the outer surface of the turbine engine. The fan thrust thus augments the thrust of the turbine engine in powering the airplane. An outer fan housing or cowling encloses the turbofan and channels the fan thrust rearwardly along the outside of the engine.
During landing, and occasionally during taxing of the airplane, it is desirable to reverse the direction of the fan thrust to produce a braking action. Reversal of the fan thrust is accomplished by deployment of a pair of fan thrust reverser cowls which operate to deflect the rearwardly directed fan thrust from the turbofan to a forward direction. The fan thrust reverser cowls form part of the outer fan housing which encloses the turbofan. The reverser cowls are ordinarily semicylindrical in configuration (C-shaped in cross section) such that the two cowls combined form a tubular body sized to match the fan housing. The reverser cowls are normally maintained in a stowed position wherein they form a continuous, faired extension of the trailing edge of the fan housing.
During deployment, the reverser cowls are moved rearwardly of parallel sets of linear hydraulic actuators which connect the reverser cowls to the fan housing. As the reverser cowls are moved rearwardly, an annular gap is opened between the trailing edge of the stationary fan housing and the forward edges of the reverser cowls. The reverser cowls include airflow deflector panels, known as blocker doors, which form part of the inner surfaces of the reverser cowls in their stowed position and which swing inwardly from the inner surfaces as the reverser cowls are moved rearwardly. The blocker doors thus operate in deployment to obstruct the rearward flow of the fan thrust along the annular channel between the reverser cowls and the outer surface of the turbine engine. More specifically, the blocker doors deflect the fan thrust airflow outwardly in generally radial directions through the annular gap between the fan housing and the reverser cowls. The radially deflected airflow is further deflected into a forward direction by sets of forwardly directed airflow vanes which are affixed to the fan housing and are positioned in the gap between the trailing edge of the turbofan housing and the leading edges of the reverser cowls. Thus, the deployment of the thrust reverser cowls causes thrust from the turbofan to be deflected to a forward direction to thereby produce a braking action on the airplane.
Because of certain engine stability requirements and fan blade fatigue stress limitations, it is imperative that the two thrust reverser cowls be moved synchronously when they are being deployed or being retracted. Failure to maintain synchronous movement of the reverser cowls will result in uneven back pressures on the blades of the turbofan. Such uneven back pressures on the spinning turbofan results in high dynamic stresses which can cause damage or even failure of the turbofan.
Previous thrust reverser cowl deployment mechanisms have achieved synchronous movement by use of mechanical interconnections between the two cowls. Specifically, a flexible rotatable shaft has been used to connect the hydraulic actuators that drive the cowls. The flexible shaft was geared to the hydraulic actuators through worm gear assemblies so as to constrain the actuators, and therefore the reverser cowls as well, to move synchronously. This approach met the requirements of synchronous movement, but imposed a substantial weight penalty on the structure due to the weight of the mechanical linkages. Additionally, the mechanical interconnection of the reverser cowls generated installation difficulties, and also interfered with a cowl opening system so as to make it difficult to gain access to the engine for maintenance purposes.
Another problem with mechanically linking the two reverser cowls to achieve synchronous movement is that, in the event of jamming or binding of one cowl during the course of its rearward displacement, the full mechanical load exerted by the actuators of both reverser cowls is applied to the jam point. This creates the possibility of extensive damage to the fan housing and engine structure due to the substantial mechanical forces exerted to deploy the reverser cowls becoming focused on one point of the fan housing structure.
Accordingly, it has been sought to provide a hydraulic positioning system for the thrust reverser cowls that operates to move the cowls independently and yet also ensure synchronous motion of the cowls. As indicated above, independent actuation of the reverser cowls is desirable in order that less powerful actuators may be used to drive each reverser cowl to thereby reduce the maximum potential load on each cowl and thus reduce the possibility of extensive damage in the event of jamming.
Another requirement of a hydraulic positioning system for the reverser cowls is that the full displacement stroke of each cowl be identical even in the event of lagging of one cowl behind the other during deployment. Identical displacement strokes are necessary for the cowls to be properly positioned at the end of each translational movement in deployment or retraction. Although lagging of one cowl behind the other is sought to be avoided for the reasons discussed above, a small amount of lagging may be tolerated and must in fact be anticipated in the design of a suitable positioning system.
This requirement of identical displacement strokes has precluded the use of one conventional approach wherein separate hydraulic actuators drive the cowls and wherein a hydraulic flow divider having a pressure feedback mechanism selectively meters fluid to one hydraulic actuator or the other in the event of a pressure differential between the actuators. With such a system increasing resistance met by one cowl results in greater force being applied to that cowl. However, once a leading cowl becomes fully deployed the flow divider causes the lagging cowl to stall with the result that full deployment of the stalled reverser cowl is not achieved.
Another conventional hydraulic system that has been considered for positioning of the thrust reverse cowls is a servovalve mechanism. Such a mechanism includes a closed loop hydraulic system similar to a primary flight control system. The disadvantage of such a system is its greater complexity due to certain mechanical feedback assemblies which are required, as well as difficulties in rigging such a more complex system in the confined space of the fan housing.
Accordingly, it is an object and purpose of the present invention to provide a hydraulic positioning and control system for fan thrust reverser cowls in a turbofan engine.
It is also an object to provide a hydraulic positioning and control system that provides substantially synchronous translation of the thrust reverser cowls during deployment as well as during retraction.
It is another object of the present invention to provide a hydraulic positioning and control system that achieves the foregoing objects and purposes and which also ensures that the thrust reverser cowls undergo substantially identical full stroke displacements during deployment as well as retraction.
It is yet another object of the present invention to attain the foregoing objects with a hydraulic system that is reliable, simple, contains few moving parts, and which does not impose a significant weight penalty on the engine.
It is a further object of the present invention to provide a hydraulic positioning and control system for a pair of fan thrust reverser cowls whereby each cowl is independently driven to thereby reduce the extent of damage that might result from failure or jamming of a cowl during deployment or retraction.
SUMMARY OF THE INVENTION
In accordance with the present invention, a hydraulic positioning and control system for fan thrust reverser cowls in a turbofan engine includes an independent set of one or more double acting hydraulic actuators associated with each cowl for moving the cowl between a retracted, or stowed, position and a deployed position. Hydraulic fluid is selectively metered through a control valve connected to a primary hydraulic system to either the head ends of the rod ends of the actuators to effect deployment or retraction of the reverser cowls. Fluid flow through each set of actuators is regulated by a pressure compensated, two-way flow regulator valve associated with each cowl and its actuators. The flow regulator valves are preferably installed in the hydraulic lines connected to the common rod ends of the actuators of each cowl. Each flow regulator valve operates to constrain the flow rate of hydraulic fluid passing through the valve in either direction, to within a range of about ±5% from a nominal value over a relatively large range of pressure differentials across the valve. The flow regulator valves are matched to have substantially identical nominal flow rates.
Because of the constant and equal rates of flow of hydraulic fluid to the cowl actuators, the thrust reverser cowls are deployed and retracted synchronously and at constant translational rates. Each cowl is deployed to the end of its displacement stroke, even in the event of a slight lag of one cowl behind another. Likewise, during retraction of the cowls the return flow of fluid from the cowl actuators is regulated by the flow regulator valves to result in substantially constant and identical rates of translation. Again, each cowl is retracted to its fully stowed position even in the event of lagging of one cowl behind another.
The possibility of extensive damage in the event of jamming of one cowl is substantially reduced over previous mechanisms because the cowls are independently driven by their associated hydraulic actuators. Thus, the maximum potential load on each cowl is the force produced by its associated hydraulic actuators. Moreover, since there is no mechanical interconnection between the cowls, the system is lighter in weight and also more reliable and safe by reasons of having fewer moving parts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic hydraulic diagram of the preferred embodiment of the hydraulic positioning and control system of the present invention.
FIG. 2 is a pictorial view showing a portion of the fan housing and the thrust reverser cowls of a turbofan jet engine.
FIG. 3 is a schematic side view in partial cross section of a turbofan engine, with the right-hand thrust reverser cowl in the stowed positions.
FIG. 4 is a cross-sectional view as in FIG. 3, with the thrust reverser cowl shown in its deployed positions.
FIG. 5 is a cross-sectional view of the thrust reverser cowl in a stowed, or retracted, position.
FIG. 6 is a cross-sectional view as in FIG. 5, with the thrust reverser cowl shown in a deployed position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the preferred embodiment of the hydraulic positioning and control system of the present invention is illustrated schematically as it is employed in a high bypass turbofan jet engine to control the deployment of a pair of left- and right-hand fan thrust reverser cowls 10 and 12.
The operation and deployment of the fan thrust reverser cowls 10 and 12 are illustrated in FIGS. 2 through 6. Referring, for example to FIGS. 3 and 4, the right-hand thrust reverser cowl 12 is viewed from the side as it is employed in a high bypass turbofan jet engine 14 affixed to an airplane wing 16 by a pylon 18. The cowl 12 is shown in its retracted, or stowed, position in FIG. 3. During normal operation, for example during takeoff or while in cruise, the thrust reverser cowl 12 forms a continuous rearward extension of the main fan housing 20. The reverser cowl 12 is faired with the fan housing 20 along both its inside and outside surfaces. Fan thrust, indicated by directional arrows 22, passes through the annular channel between the thrust reverser cowl 12 and the main body 24 of the turbine engine.
In FIG. 4, the fan thrust reverser cowl 12 is shown in a rearward, deployed position. Deployment of the reverser cowl 12 causes a set of blocker doors 26, which form part of the inside surface of the cowl 12 in the retracted position, to swing inwardly to block the annular channel between the cowl 12 and the main body 24 of the engine. At the same time, sets of fixed airflow turning vanes 28 are exposed. The vanes 28 are affixed to the fan housing 14 and are normally stowed within slots 30 in the thrust reverser cowl 12. The net effect of deploying the blocker doors 26 and the vanes 28 is to cause the fan thrust airflow to be deflected radially outwardly and forwardly, as indicated by the directional arrows 32 in FIG. 4.
The operation of the blocker doors 26 and the thrust reverser cowl 12 are indicated in greater detail in FIGS. 5 and 6. With the cowl 12 retracted for cruise, the outer surface of the cowl 12 is smoothly faired with the outer surface of the main housing cowl 20, as indicated in FIG. 5, and the blocker door 26 forms a smooth extension of the inner surface of the cowl 12. As the cowl 12 is deployed rearwardly, as in FIG. 6, the blocker door 26 swings inwardly and is braced by strut 34.
Referring to FIGS. 1 and 2, the left-hand reverser cowl 10 is actuated by three double acting, single rod, linear hydraulic actuators 40, 42, and 44 which are mechanically linked in a manner described below. Likewise, the right-hand reverser cowl 12 is driven by three double acting, single rod, actuators 46, 48, and 50 which are spaced around the semicircular leading edge of the reverser cowl 12 and affixed to the trailing edge of the fan housing 20.
Referring to FIG. 1, the actuators 40, 42 and 44 of the left-hand reverser cowl 10 include cylinders 52, 54 and 56, which are affixed to the fan housing 20, and movable pistons 58, 60 and 62, respectively. Extending rearwardly from the pistons are piston rods 64, 66 and 68, respectively, which are attached at their opposite ends to the reverser cowl 10.
The pistons of the inner hydraulic actuators 40, 42 and 44 are mechanically linked together so as to be constrained to move synchronously. More specifically, the actuators include acme screws 70, 72 and 74, which are threaded to their associated pistons 58, 60 and 62, respectively. Linear translation of the pistons 58 through 62 results in rotation of the acme screws 70 through 74. The acme screws 70, 72 and 74 are linked to one another by flexible synchronization shafts 76 and 78, which are connected to the acme screws by means of worm gear assemblies 80, 82 and 84. The function of the acme screws and the flexible synchronization shafts is to constrain the pistons and rods of the hydraulic actuators 40 through 44 to move synchronously and in tandem at all times. As a result, the thrust reverser cowl 10 is evenly deployed and retracted with a smooth translational motion.
The operation of the hyraulic actuators 46, 48 and 50 associated with the right-hand reverser cowl 12 is identical to that described above with respect to the actuators 40 through 44 of the left-hand reverser cowl 10, i.e., the rods of the actuators 46 through 50 are mechanically linked by flexible synchronization shafts 53 and 55.
The hydraulics of the actuator assemblies for the left- and right-hand reverser cowls 10 and 12 are also identical. Accordingly, the following description of the hydraulics of the right-hand reverser cowl 12 is applicable also to the hydraulics of the actuators 40 through 44 associated with the left-hand cowl 10.
The positioning and control system includes generally an isolation valve assembly 86, a directional control valve 88 and a flow regulator valve assembly 90. These assemblies are each described in greater detail below. Briefly, the function of the isolation valve assembly 86 is to isolate the entire positioning and control system from the main airplane hydraulic system at times when the thrust reverser cowls are not actually being deployed or retracted. During such times, the positioning and control system for the reverser cowls is depressurized and isolated from the main hydraulics system, and the hydraulic actuators 40 through 50 and their associated reverser cowls 10 and 12 are locked in position with locking mechanisms described in greater detail below.
The directional control valve 88 selectively meters hydraulic fluid to the actuators to deploy or retract the reverser cowls 10 and 12. The flow regulator assembly 90 operates to cause the left- and right-hand reverser cowls 10 and 12 to be deployed or retracted synchronously and in parallel alignment. To deploy or retract the reverser cowls, the pilot must first arm the solenoid-actuated isolation valve assembly 86 and then actuate the directional control valve assembly 88. These assemblies are each described in greater detail below.
The isolation valve assembly 86 is connected to system pressure and return hydraulic lines 92 and 94 which are connected in turn to the main airplane hydraulic system. The pressure line 92 is ordinarily maintained at the system operating pressure of approximately 3,000 psi and the system return line 94 is ordinarily at the negligible pressure of the airplane hydraulic return system.
The isolation valve assembly 86 includes a two-position, three-way solenoid valve 96 and a double-piloted, two-position, three-way arming valve 98. The arming valve 98 includes a pilot port 100 which is connected by a hydraulic line 102 to an output port 103 of the solenoid valve 96. A second pilot port 104 of the arming valve 98 is connected to the system pressure line 92. As indicated schematically in FIG. 1, the pilot piston associated with pilot port 100 is larger than the pilot piston associated with the pilot port 104 so as to obtain an effective pressure biasing of the piloted arming valve 98 when both ports 100 and 104 are equally pressurized. The system pressure line 92 is also connected to an input port 105 of the solenoid valve 96 and an input port 106 of the arming valve 98.
In the absence of electrical actuation of the solenoid valve 96 by its associated solenoid, the solenoid valve 96 is spring biased to a closed position wherein the hydraulic line 102 and the pilot port 100 are closed to the system pressure line 92 and open to the return line 94. Thus, the absence of actuation of the solenoid, the pressure actuated pilot of port 104, together with an auxiliary bias spring 107, operate to maintain the arming valve 98 in a closed position wherein an output port 108 is closed to the system pressure line 92 and open to the system return line 94 via a one-way check valve 110. The auxiliary spring 107 operates further to maintain the arming valve 98 in this closed position in the event of a failure of system pressure in line 92. The output port 108 of the arming valve is connected to a hydraulic line 112 which, when pressurized at the system pressure, operates to retract the reverser cowls 10 and 12 to the stowed position, as described further below.
Upon electrical actuation of the solenoid of solenoid valve 96, the system pressure line 92 is connected in fluid communication with the hydraulic line 102. The resulting pressurization of the pilot of port 100 overpowers the smaller pilot of port 104 and the auxiliary bias spring 107 to open the arming valve 98. Upon opening of the arming valve 98, the system pressure line 92 is connected in fluid communication via port 108 with the hydraulic line 112. With the arming valve 98 opened and the hydraulic line 112 thereby pressurized at system pressure, the thrust reverser cowls 10 and 12 may be selectively deployed or retracted, as described below.
The directional control valve 88 is a two-position, spring biased, three-way valve. The hydraulic pressure line 112 from the isolation valve assembly 86 is connected to one input port 114 of the directional control valve 88. A second port 116 of the valve 88 is connected to a hydraulic return line 118, which is connected to the system return line 94 through the one-way check valve 110 in the isolation valve assembly 86. A two-position, two-way, spring biased manual bypass valve 120 is also interposed between the return hydraulic line 118 and the system return line 94 in the isolation valve assembly 86. The bypass valve 120 includes an external locking mechanism 121 by which the return line 118 may be kept open to the system return line 94 during servicing or maintenance.
A hydraulic pressure line 113 (also labelled STOW) is connected to line 112 and bypasses the directional control valve 88 and passes into the flow regulator assembly 90 where it is connected to each of two two-way flow regulator valves 122 and 124. The flow regulator valves 122 and 124 are pressure compensated and matched with one another so as to conduct fluid flow in either direction at substantially constant flow rates over pressure ranges of approximately 100 psi to 4,000 psi. Hydraulic fluid passing through the flow regulator valve 122 from the pressure line 113 passes through a hydraulic line 126 to the rod ends of the hydraulic actuators 40, 42 and 44 associated with the left-hand reverser cowl 10. Likewise, hydraulic fluid passing through the regulator valve 124 from the pressure line 113 passes through a hydraulic line 128 and is distributed therefrom to the rod ends of the hydraulic actuators 46, 48 and 50 of the right-hand reverser cowl 12. Thus, with the isolation valve assembly 86 opened and the directional control valve 88 in its normal spring biased position, as illustrated in FIG. 1, pressurized hydraulic fluid is applied to the rod ends of the hydraulic actuators to thereby retract the rods of the actuators and move the thrust reverser cowls 10 and 12 toward their stowed positions.
Referring to the actuators 46, 48 and 50 of the right-hand reverser cowl 12 in FIG. 1, the head ends of the actuators 46 through 50 are connected in fluid communication with one another through conduits 129 and 130 enclosing the flexible synchronizaion shafts 52 and 54, respectively. Hydraulic fluid is provided to and exhausted from the head ends of the actuators 46 through 50 through a hydraulic line 131 having a one-way check valve 132 and a lock valve 133 interposed in parallel therein. The hydraulic line 131 is connected to one port of a pressure limiting valve 134 in the flow regulator assembly 90. The pressure limiting valve 134 is a variable, spring biased, piloted valve. The pilot of the pressure limiting valve 134 is connected in fluid communication to hydraulic line 128 by hydraulic line 136. The second port of the pressure limiting valve 134 is connected to a hydraulic line 138, also labelled DEPLOY, which is in turn connected to a port 140 of the directional control valve 88.
Likewise, the common head ends of the actuators 40, 42 and 44 of the left-hand reverser cowl 10 are connected by a hydraulic line 142 to a second pressure limiting valve 144 through a check valve 146 and a lock valve 147. The hydraulic line 138 connects the second port of the pressure limiting valve 144 to port 140 of the directional control valve 88.
The actuator assemblies of reverser cowls 10 and 12 further include mechanical locking mechanisms 160 and 162 which are mechanically connected to the lock valves 147 and 133, respectively. The lock valves 147 and 133 are two-position, two-way, spring biased piloted valves which are mechanically linked to the locking mechanisms 160 and 162. Pressurization of the hydraulic lines 138, 131, and 142 pressurizes pilot ports 164 and 165 and thereby opens the lock valves 147 and 133, and also operates to unlock the locking mechanisms 160 and 162 to free the actuators for translational movement. If the pressure in the hydraulic lines 131 and 142 drops below a certain predetermined level, the bias springs of the lock valves 147 and 133 operate to close the valves, lock the locking mechanisms 160 and 162, and thereby restrict flow of fluid in the hydrualic lines 131 and 142 to the direction permitted by the check valves 132 and 146. In effect, the lock valves 133 and 147, when actuated by sufficient pressure in the hydraulic lines 131 and 142, operate to unlock the locking mechanisms 160 and 162 and also permit fluid to bypass the check valves 146 and 132 to permit flow of hydraulic fluid to the head ends of the reverser cowl actuators 40 through 50.
To operate the positioning and control system illustrated in FIG. 1, an electrical signal is first transmitted to the solenoid of the valve 96 in the isolation valve assembly 86. This admits pressurized hydraulic fluid to hydraulic line 102 and pilot port 100 and thereby opens the arming valve 98 to connect the hydraulic lines 112 and 113 (STOW) to the system pressure line 92. Pressurization of hydraulic line 112 with the directional control valve 88 in its normal spring biased position (as shown) results in pressurization of the rod ends of the reverser cowl actuators 40 through 50 through lines 126 and 128 and thereby retracts the reverser cowls 10 and 12. More specifically, if the reverser cowls are in a deployed position, pressurization of hydraulic lines 112 and 113 by actuation of the isolation valve assembly 86 results in constant flow rates of fluid through the regulator valves 122 and 124 and thence through hydraulic lines 126 and 128 to the rod ends of all of the hydraulic actuators 40 through 50. Since the flow rates to the two sets of hydraulic actuators are substantially identical, and since the hydraulic actuators of each set are mechanically linked, a uniform and synchronous motion of the left- and right-hand reverser cowls 10 and 12 is achieved. The left- and right-hand reverser cowls 10 and 12 are retracted until they are in their fully stowed positions at the ends of their displacement strokes. During the retraction of the reverser cowls 10 and 12, hydraulic fluid is exhausted from the head ends of the actuators 40 through 50 through hydraulic lines 131 and 142, thence through the pressure limiting valves 134 and 144, thence through the common hyraulic line 138 and the directional control valve 88, and finally through the hydraulic return line 118 to the system return line 94. During exhaustion of fluid from the head ends of the actuators 40 through 50, the hydraulic lines 131 and 142 are at or near the pressure of the system return line 94, such that the pilot ports 164 and 165 of the lock valves 147 and 133 are depressurized, such that the valves 147 and 133 are closed and the fluid is constrained to flow through the one-way check valves 132 and 146. When the left- and right-hand reverser cowls 10 and 12 reach the ends of their displacement strokes, the locking mechanisms 160 and 162 automatically lock the central actuators 42 and 48 to thereafter maintain the reverser cowls mechanically locked in the stowed or retracted position until such later time as the hydrualic lines 131 and 142 are pressurized for deployment of the cowls 10 and 12. A pair of lock indication switches 180 and 182 provide an electrical signal indicating the locked condition of the actuators 42 and 48.
With the reverser cowls 10 and 12 fully retracted and mechanically locked in place, the entire system may be depressurized by deactuation of the isolation valve assembly 86, with the locking mechanisms 160 and 162 retaining the reverser cowls in the stowed position. The system is normally maintained in this condition during flight.
To deploy the reverser cowls 10 and 12 from their stored positions, for example during landing of the airplane, the isolation valve assembly 86 is actuated to pressurize hydraulic line 112 as before. The directional control valve 88 is also actuated to thereby connect ports 114 and 140 of the valve 88 and thereby connect hydraulic line 138 to the pressurized hydraulic line 112. Thus, hydraulic lines 112, 113 and 138 are all pressurized to effect deployment of the reverser cowls. As a result of pressurization of hydraulic fluid in line 138, and thus also in lines 131 and 142, the piloted locking valves 147 and 133 are opened to connect the head ends of the actuators 40 through 50 to the hydraulic lines 142 and 131. Actuation of the piloted locking valves 147 and 133 also operates to unlock the locking mechanisms 160 and 162 and frees the actuators 40 through 50 for deployment. It will be seen that this results in pressurization of both the rod ends and the head ends of the actuators 40 through 50. The areas of the pistons facing the head ends of the actuators 40 through 50 are each approximately twice as great as the areas of the pistons facing the rod ends of the actuators. Accordingly, equal pressurization of the head and rod ends of the actuators 40 through 50 results in a net deployment force which acts to extend the rods and thereby deploy the reverser cowls 10 and 12 rearwardly. During deployment of the cowls 10 and 12, hydraulic fluid is exhausted from the rod ends of the actuators 40 through 50 through the hydraulic lines 126 and 128 and thence through the two-way flow regulator valves 122 and 124. The flow regulator valves 122 and 124 thus operate to constrain the deployment of the reverser cowls 10 and 12 at equal and synchronous rates. The fluid flow through the flow regulator valves 122 and 124 is combined in and passes through hydraulic line 113. This combined fluid flow in line 113 is further combined with hydraulic fluid flowing through the line 112 from the isolation valve assembly 86. These combined flows of hydraulic fluid in lines 113 and 112 together make up the net fluid flow through the directional control valve 88 and thence through the hydraulic line 138.
Referring again to FIGS. 3 through 6, it will be seen that during deployment of the reverser cowls, the fan thrust (22) engages the inwardly swinging blocker doors 26 to result in the reverser cowls 10 and 12 being effectively pulled rearwardly. The combined force arising from the fan thrust on the blocker doors 26 and the pressure of the hydraulic fluid in the head ends of the actuators 40 through 50 can result in excessive pressures building up in the rod ends of the actuators 40 through 50. That is, although it is necessary to drive the reverser cowls rearwardly by pressurization of the head ends of the actuators 40 through 50 in the initial stages of deployment, in the later stages the fan thrust engages the emerging blocker doors 26 to effectively drive the reverser cowls rearwardly without any need for pressurization of the head ends of the actuators 40 through 50 and actually placing a substantial rearward air load on the reverser cowls. In the event this combination of air and hydraulic loads produces excessive pressure buildup in the rod ends of the actuators 40 through 50, the pressure limiting valves 134 and 144 of the flow regulator assembly 90 are actuated to restrict the pressure of fluid flowing from the common line 138 to the hydraulic lines 131 and 142 leading to the head ends of the actuators 40 through 50. Accordingly, the hydraulic pressure in the head ends of the actuators is reduced to thereby reduce the pressure in the rod ends to acceptable levels.
In other embodiments of the invention, the flow regulator valves 122 and 124 could be interposed in hydraulic lines connected to the head ends of the actuators 40 through 50, rather than in the hydraulic lines connected to the rod ends as in the preferred embodiment. In such embodiments, the pressure limiting valves would not be required because the flow regulator valves would assume the function of the pressure limiting valves to some extent and reduce the pressure of the fluid applied to the head ends of the actuators. However, under the load conditions commonly encountered in the turbofan engines for which the present system was developed, the pressure applied to the head ends of the actuators during deployment of the reverser cowls could occasionally fall below the level at which the lock valves 147 and 133 are actuated by their associated biasing springs, thus resulting in stoppage of flow to the head end of the actuators and stalling of the reverser cowls in midstroke. To avert this possiblity, in the preferred embodiment of the positioning and control system, the flow regulator valves 122 and 124 are interposed in the hydraulic line connected to the rod ends of the actuators 40 through 50. In other similar applications, however, the flow regulator valves 122 and 124 could be equally well placed and the hydraulic lines connected to the head ends of the actuators.
Although the present invention is described and illustrated herein by reference to a preferred embodiment, it will be understood that various modifications, alterations and substitutions may be made without departing from the spirit of the invention. Accordingly, the scope of the invention is defined by the following claims.
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A positioning and control system for fan thrust reverser cowls in a high bypass turbofan jet engine includes independent hydraulic actuator assemblies for selectively moving the cowls between a forward stowed position and a rearward deployed position. Hydraulic fluid is metered to the actuator assembly through matched, two-way, pressure compensated flow regulator valves associated respectively with each actuator assembly. The flow regulator valves are preferably interposed in the hydraulic lines of the rod end of the actuators so as to regulate the rate of translation of the thrust reverser cowls during both deployment and retraction. The use of matched flow regulator valves in parallel results in synchronous translation as well as substantially identical full stroke displacements of the reverser cowls during both deployment and retraction. Additionally, the use of matched flow regulator valves in parallel permits independent actuation of the thrust reverser cowl with lighter and more efficient actuator assemblies.
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BACKGROUND
Electronic paper (“e-paper”) is a display technology designed to recreate the appearance of ink on ordinary paper. E-paper reflects light like ordinary paper and may be capable of displaying text and images indefinitely without using electricity to refresh the image, while allowing the image to be changed later. E-paper can also be implemented as a flexible, thin sheet, like paper. By contrast, a typical flat panel display does not exhibit the same flexibility, typically uses a backlight to illuminate pixels, and constantly uses power during the display. Typical e-paper implementations, such as electronic books (“e-books”), include an e-paper display and electronics for rendering and displaying digital media on the e-paper.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate various examples of the principles described herein and are a part of the specification. The illustrated examples are merely examples and do not limit the scope of the claims.
FIG. 1A is a plan view of an illustrative piece of electronic paper, according to one example of principles described herein.
FIG. 1B is a cross sectional view of a portion of the electronic paper, according to one example of principles described herein.
FIGS. 2A and 2B are examples of illustrative e-paper applications, according to one example of principles described herein.
FIG. 3 is cross sectional diagram of an illustrative e-paper printing system, according to one example of principles described herein.
FIG. 4 is a cross sectional view of an illustrative e-paper structure which includes a porous standoff layer, according to one example of principles described herein.
FIGS. 5A and 5B are a cross sectional view and a plan view, respectively, of an e-paper test coupon with a porous standoff layer, according to one example of principles described herein.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.
DETAILED DESCRIPTION
E-paper is used in a variety of display applications such as signage, e-books, tablets, cards, posters, and pricing labels. E-paper has several paper-like features. For example, e-paper is a reflective display that uses ambient light as an illumination source. The ambient light strikes the surface and is reflected to the viewer. The usage of pigments similar to those which are used in printing allows the e-paper to be read at a wide range of angles and lighting conditions, including full sunlight. The use of ambient light also eliminates the need for illumination produced by the device. This minimizes the energy used by the e-paper. Additionally, the e-paper does not use energy to maintain the image. Once the image is written, the image remains on the e-paper for an extended period of time or until the e-paper is rewritten. Thus, a typical e-paper primarily uses energy for changes of state.
E-paper is typically written by generating a charge on a surface in proximity to a layer of microcapsules that contain charged pigment particles. The charge on the surface attracts or repels the charged pigment particles in the microcapsules to create the desired image. The pigment particles are stable within the microcapsules after they are moved into position. However, a wide variety of methods can be used to alter the image or text on the e-paper after it has been written. This can restrict the use of e-paper to applications that do not require the images or text to be secure against alteration. However, the principles described below illustrate a porous standoff layer that prevents alteration of e-paper using common techniques such as an electrified stylus or corona discharge mechanisms. By preventing alteration of the e-paper using easily accessible technology, the security of the e-paper improves and the e-paper can be used a wider variety of applications.
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present systems and methods. It will be apparent, however, to one skilled in the art that the present apparatus, systems and methods may be practiced without these specific details. Reference in the specification to “an example” or similar language means that a particular feature, structure, or characteristic described in connection with the example is included in at least that one example, but not necessarily in other examples.
FIG. 1A shows a plan view of an illustrative piece of e-paper 102 and includes an enlargement 104 of a small portion of the e-paper 102 . The enlargement 104 shows that this e-paper implementation includes an array of embedded, spherical-shaped microcapsules 106 . The line 118 is created by selectively applying a charge to the e-paper 102 . The charge moves the particles within the microcapsules 106 . In this example, a charge has been applied that moved dark particles to the front of the microcapsules 114 to form the line 118 .
FIG. 1B is a cross-sectional view of a portion of the e-paper 102 shown in FIG. 1A . The cross-sectional view shows an illustrative multilayer structure of the e-paper 102 , including an active layer 109 with microcapsules 106 , 114 sandwiched between a transparent charge receiving layer 108 and a conductive ground layer 110 . As shown in FIG. 1B , the conductive ground layer 110 is disposed on a substrate 112 .
In this example, each of the microcapsules 106 , 114 contains both white particles 120 and black particles 124 suspended in a fluid medium. Ambient light is transmitted through the charge receiving layer 108 , strikes the pigment, and reflected back to the viewer 122 . When white particles 120 of a microcapsule are located near the transparent charge receiving layer 108 , the microcapsule appears white to a viewer 122 , and when the black particles 124 of a microcapsule are located near the charge receiving layer 108 the microcapsule appears black to the viewer 122 . The particles can be of opposite charges. For example, the black particles 124 can be positively charged particles and the white particles 120 can be negatively charged particles. Various shades of gray can be created by varying the arrangement of alternating microcapsules with white and black particles located near the charge receiving layer 108 to produce halftoning.
The microcapsules 106 , 114 are designed to exhibit image stability using chemical adhesion between particles and/or between the particles and the microcapsule surface. For example, the black and white microcapsules 106 , 114 ideally can hold text and images indefinitely without drawing electricity, while allowing the text or images to be changed later.
The structure, materials, and dimensions of the various layers and components shown in FIG. 1B can be adapted to specific design criteria. In one implementation, the transparent charge receiving layer 108 can be composed of a transparent polymer and can range in thickness from approximately 100 nm to approximately 14 μm. The transparent charge receiving layer 108 can also be composed of a material that holds charges or is porous or semi-porous to charges and/or ions. The transparent charge receiving layer 108 can also be composed of a first insulating layer and second patterned conductive layer.
The microcapsules 106 , described in greater detail below, can have a diameter of approximately 50 μm but may also range in diameter from approximately 20 μm to approximately 100 μm. The conductive ground layer 110 can be composed of a transparent conductive material, such as indium tin oxide, or an opaque conductive material and can have a thickness ranging from approximately 5 nm to approximately 1 mm. In one example, the layers 108 , 109 , and 110 have a total thickness of approximately 100 μm. The substrate 112 can be composed of an opaque or transparent material and can range in thickness from approximately 20 μm to approximately 1 mm, or the thickness can be much larger depending on the how the e-paper is used. The substrate 112 can be composed of polyester, plastic, or transparent Mylar. In some implementations, the substrate 112 can be omitted and the layers 108 , 109 , and 110 can be mounted on a wall or a product chassis. In this case, the transparent charge receiving layer 108 serves as a wear protection layer for the layer of microcapsules 109 and normalizes the e-paper surface, eliminating surface topography and blocking surface conduction paths on the microcapsule surfaces.
A variety of other configurations may be used. For example, the microcapsule 106 may include black particles suspended in a white colored fluid. The black particles can be positively charged particles or negatively charged particles. One or more microcapsules form a pixel of black and white images displayed on the e-paper 102 . The black and white images are created by placing black particles near or away from the charge receiving layer 108 . For example, the microcapsules 106 with black particles located away from the transparent charge receiving layer 108 reflect white light, corresponding to a white portion of an image displayed on the e-paper. By contrast, the microcapsules with black particles located near the charge receiving layer 108 , such as microcapsule 114 , appear black to the viewer 122 , corresponding to a black portion of the image displayed on the e-paper 102 . Various shades of gray can be created using halftoning to vary the arrangement of alternating microcapsules with black particles located near or away from the charge receiving layer 108 .
Where the microcapsules include black particles suspended in a white colored fluid, the charge receiving layer 108 may be tinted with alternating blue, red, and green regions. Adjacent blue, red, and green regions form color pixels. Color images are created by placing different combinations of white or black particles near the charge receiving layer 108 . For example, the microcapsules of color pixel with white particles located near the red and green regions of the transparent charge receiving layer 108 reflect red and green light from the e-paper. The viewer 122 will perceive this combination as a yellow pixel. When the black particles in the microcapsules are located near the transparent charge receiving layer 108 , that color pixel will appear black to the viewer 122 . Additionally or alternatively, the black particles 124 of each microcapsule are replaced by either blue, red, or green positively, or negatively, charged particles. Particles could be used alone or in combination with a tinted charge receiving layer 108 to create the desired color image.
FIGS. 2A and 2B show two illustrative cards 200 , 205 that use a strip of e-paper 204 across the width of the card to display information. As discussed above, it may be desirable to secure the information displayed by the e-paper against alteration. FIG. 2A is a gift card 200 used in a retail setting. The card 200 displays text 214 that communicates the amount remaining on the card 200 . Additional text 208 and an image 202 describing a featured product are also included on the card 200 . If the text 214 has not been secured against alteration, it cannot be relied on to accurately communicate the balance of the card. Consequently, other techniques such as a magnetic strip or embedded radio frequency circuitry may be included in the card to communicate the balance of the card.
FIG. 2B is a security card 205 that grants the user access to specific buildings for a predetermined period of time. The user's name 206 and access permissions 210 are printed on the e-paper 204 . The use of e-paper 204 allows the user and others to visually identify the information that is associated with the card. However, if the e-paper 204 has not been secured against alteration, the text 206 , 210 cannot be relied upon and alternative techniques are employed to communicate the identity of the card, the name of the card bearer and the access privileges of the card bearer.
FIG. 3 describes writing to illustrative unsecured e-paper 102 with a writing system 300 . The writing system 300 includes a writing module 302 , writing unit 304 , and an erasing unit 306 . The writing unit 304 and erasing unit 306 are connected to the same side of the writing module 302 that faces the outer surface 308 of the charge receiving layer 108 , with the writing unit 304 suspended above the surface 308 . In the example of FIG. 3 , the writing unit 304 is an ion head and the erasing unit 306 can be an electrode that comes into close contact with, or can be dragged along, the surface 308 in front of the ion head 304 . The writing module 302 can be moved in the direction indicated by the arrow and the e-paper 102 can be held stationary; or the e-paper 102 can be moved in the opposite direction and the writing module 302 held stationary; or the writing module 302 and e-paper 102 can be moved simultaneously. In the example shown in FIG. 3 , the black particles 124 and the white particles 120 of the microcapsules are positively charged and negatively charged, respectively. The erasing unit 306 erases any information stored in the microcapsules prior to writing information with the ion head 304 . In the example shown in FIG. 3 , as the e-paper 102 passes under the writing module 302 , the positively charged erasing unit 306 can remove negatively charge ions attached to the surface 308 . The positively charge erasing unit 306 also creates electrostatic forces that drive positively charged black particles 124 away from the charge receiving layer 108 and attract negatively charged white particles 120 toward the charge receiving layer 108 . By passing the erasing unit 306 over the charge receiving layer 108 , the information written to the e-paper 102 is erased by positioning the negatively charged white particles 120 near the top of the microcapsules and pushing the positively charged black particles 124 to the bottom of the microcapsules 106 . Additionally or alternatively, a corona source or the ion head 304 could be used to erase prior images present on the e-paper.
FIG. 3 also shows an illustrative writing operation performed by the ion head 304 . The ion head 304 is designed and operated to selectively eject ions 314 (shown as black bars) toward the charge receiving layer 108 , when a region of the e-paper 102 located beneath the ion head 304 is to be changed from white to black. The ions 314 reach the surface 308 and remain on the surface to create negatively charged areas 316 . The negatively charged white particles 120 are repelled and driven away from the negatively charged areas 316 on the charge receiving layer 108 , while the positively charged black particles 124 are attracted to the negatively charged area 316 and driven toward the charge receiving layer 108 . For example, as shown in FIG. 3 , as the ion head 304 passes over a portion of microcapsule 106 while ejecting electrons/ions 314 , the negatively charged white particles 120 are repelled away from the charge receiving layer 108 and the positively charged black particles 124 are driven toward the charge receiving layer 108 . Thus, to a viewer 122 , the positively charged areas of the charge receiving layer 308 will appear white and the negatively charged areas 316 will appear black.
In addition to ion heads, a number of alternative writing devices can be used to write on the e-paper or alter the contents of the e-paper. One of the simplest writing devices is a charged stylus that is manually brought into proximity with the charge receiving surface. The tip of the charged stylus creates an electromagnetic field which can influence the position of the charged pigments in the microcapsules 106 .
In contrast to this relatively simple stylus, the use of an ion head 304 to write to e-paper is much more involved. The construction of the ion head 304 is exacting and requires specialized equipment. The operation of the ion head 304 includes computerized control and data transfer. The construction or use of an ion head 304 to forge or alter e-paper is a significant hurdle that many forgers may be unable or unwilling to implement.
Securing e-paper 102 against alteration by a charged stylus or other field writing device while allowing alteration by an ion head 304 can result in e-paper 102 being significantly more secure. Consequently, the visual information conveyed by the e-paper 102 could be relied on to a greater extent. This may reduce the need for alternative technology to be incorporated into the card. Further, the information conveyed by secured e-paper 102 could be used to visually verify the information conveyed by a magnetic strip, embedded microchip or other technology.
FIG. 4 is a cross sectional diagram of an illustrative secure e-paper 402 . The secure e-paper 402 includes a substrate 112 , a ground plane 110 , an active layer 410 that includes microcapsules 106 , and a standoff layer 408 that imposes an electrical standoff distance while being permeable to free ions. This standoff layer 408 may be implemented in a variety of ways. In one implementation, the standoff layer 408 is formed from material that is porous at the appropriate length scale. For example, screen meshes that have porosity levels of approximately 60% and openings in the range of 0.0059″ showed good imaging capabilities with a 300 dot/inch ion head while preventing image modification with a stylus at a 600 Volt potential.
FIG. 4 shows an ion head 304 positioned over the e-paper 402 and directing a stream of ions 314 toward the e-paper 402 . A stylus 404 is brought into contact with the standoff layer 408 and equipotential lines 406 are shown emanating from the stylus 404 , through the standoff layer 408 and into the active layer 410 .
There are several differences between writing an image with an ion beam device 304 and a stylus 404 . An ion beam 314 may be kept focused over long distances with a relatively small field (<1 v/μm to keep a 50 μm beam focused over lengths of 250-500 μm). However, the electrical potential generated by a stylus 404 rapidly becomes larger and weaker with distance. For example, the equipotential lines 406 generated by the stylus 404 are nominally spherical, so for a stylus of radius R kept at an offset d from the imaging plane (i.e. the imaging plane is where the dot will be formed), the spot diameter will be roughly ˜2x(R+d). If the radius R of the stylus 404 is 50 μm and the thickness d of the standoff layer 408 is 50 μm, the effective spot diameter at the active layer 410 is roughly ˜200 μm.
This is shown schematically in FIG. 4 . In practice, the effect of the offset is slightly worse than the calculation given above or the illustrated equipotential lines shown in FIG. 4 . This is because the proximity of the ground plane causes the equipotential lines to become flat at the ground plane 110 . This further increases the spot size generated by the stylus 404 .
To allow ion printing through the standoff layer 408 , the standoff layer is porous. This allows the ion beam 314 to permeate the standoff layer 408 and directly influence the position of the charged pigments in the active layer 410 . However, the physical offset will cause a much greater increase in the image spot from the stylus/styli 404 . Further, the physical offset severely reduces the voltage potential created by the stylus 404 . Consequently, using a stylus 404 in an attempt to alter an image in the secure e-paper results in vague, low resolution markings. In many instances, the stylus 404 will have no visible impact on the image at all.
The amount of porosity in the standoff layer 408 can be selected using a number of factors. Less porous surfaces have a tendency to accumulate charges from the ion head and cause an increase in spot size. However, a less porous standoff layers may be more robust and less prone to absorb contaminants. For example, the less porous layer may have fewer or smaller pores. A more porous standoff layer may permit the ion beam to pass more efficiently to the active layer.
The standoff layer 408 can be formed from a range of materials and have a variety of pore structures. In one implementation the porosity may be simple grain boundaries or micron scale pores, such as those encountered in anodized aluminum layers. In another implementation, open cell micro-foam of a suitable dielectric material could be formed over the active layer 410 . Alternatively, a variety of printing and lithographic processes could be used to form a mesh structure over the active layer 410 . For example, an impression die could be pressed into a dielectric coating in an uncured state. Another manufacturing method would be to etch a porous structure onto a solid film/coating. This porous coating would still provide a tough mechanical protection to the e-paper 402 .
In addition to porosity, the resistivity of the standoff layer 408 can be important. For example, the resistivity of the standoff layer 408 can be between 10 8 to 10 14 ohm centimeters. This resistivity provides a layer time constant of no more than 10 seconds to eliminate reverse charging during handling after imaging and no less than 0.1 seconds to prevent lateral charge flow (blooming) during the e-ink switching time. In one example, the resistivity of the standoff layer 408 is between 10 11 to 10 13 ohm centimeters.
In other examples, the standoff layer 408 may exhibit macro-level porosity such as encountered in commercially available meshes with sizes between 60-325 openings per linear inch. In one implementation, mesh with between 100 to 180 openings per inch can be used. Mesh with 180 openings per inch has a filament spacing of approximately 140 μm and a filament diameter of about 70 μm. This creates a stylus spot size of approximately 140 μm plus the stylus diameter. To provide a high level of permittivity to the ion beam created by the ion head 304 , it can be desirable to employ meshes having a high percentage of open area. Open areas of 60 percent are readily available and perform well. For example, nylon mesh may be used as the standoff layer 408 . Nylon meshes have an electrical resistivity that ranges from between approximately 10 9 to 10 12 ohm centimeters depending on the processing conditions, additives and moisture content. When using these meshes as offset layers, writing to the e-paper 402 with a stylus 404 is ineffective and while writing to the e-paper 402 with an ion head 304 is relatively unimpeded.
The standoff layer 408 could be formed from a variety of materials. For example, the standoff layer 408 could be formed from a hydrophobic material or have a hydrophobic coating. This would protect the exposed surface of the standoff layer 408 from accumulating a potentially harmful layer of a liquid electrolyte such as sweat or atmospheric moisture. A number of additional layers may also be included in the e-paper 402 . For example, a thin coating layer may provide a bond between the porous layer and the e-ink.
FIGS. 5A and 5B are illustrations of a 15 mm by 30 mm test coupon that was constructed and tested according to the principles described above. FIG. 5A is a cross-sectional view of the test coupon and FIG. 5B is a plan view of the viewing side of the test coupon.
As shown in FIG. 5A , the test coupon includes a ground layer 508 , an active layer 506 that contains the microcapsules, and a charge receiving layer 504 . The left hand portion of the charge receiving layer 504 has been covered by a nylon mesh standoff layer 502 . Two electrodes 510 at either end of the test coupon 500 provide electrical contact with the ground plane 508 .
To form the test coupon 500 , microcapsules were deposited on the ground plane 508 to form the active layer 506 . The charge receiving layer 504 was deposited over the active layer 506 . In this example, the charge receiving layer 504 is formed using a white alkyd enamel paint deposited using a draw down bar. The coating gap was 62 microns and the dry coating thickness 75 microns. In some implementations, the charge receiving layer 504 may have semiconducting properties. For example, the charge receiving layer 504 may have an electrical resistance between 10 3 to 10 12 ohm-centimeters.
After a short drying period to set the paint, a 104 mesh (per inch) nylon screen was pressed into the coating 504 to form the standoff layer 502 . The dry thickness in the screen area was measured to be 150 microns. The screen filament diameter is 0.0037 inch and the open gap 0.0059 inches on a side.
An ion print head 304 passed over both the exposed charge receiving layer 504 and the mesh standoff layer 502 . The ion print head 304 deposited charges onto the charge receiving layer 504 as a row of dots. The ion print head 304 made two passes over the test coupon 500 resulting in two rows of dots. A first row of dots were formed using a pulse length of 50 microseconds.
A stylus 404 was also passed over both the exposed charge receiving layer 504 and the mesh standoff layer 502 . In this example, the stylus 404 has a 0.5 mm diameter. During the first pass, 200 volts was applied to the stylus 404 . During the second pass 400 volts was applied to the stylus 404 and on the third pass 600 volts was applied to the stylus 404 . The marks made by the deposited charges are viewed from the opposite side as illustrated by the viewer 122 .
FIG. 5B is a plan view of the viewing side of the test coupon 500 . In this example, the viewing side looks through ground plane 508 , FIG. 5A . FIG. 5B shows dot images 518 , 519 made using the ion print head 304 , FIG. 5A and lines made using the stylus 404 , FIG. 5A . The mesh standoff layer 502 underlies the left side of the test coupon 500 , while the right side of the test coupon 500 includes only white alkyd paint. Thus, the left side of the test coupon 500 is protected from alteration by a stylus, while the right side of the test coupon 500 is not.
The images 512 , 514 , and 516 formed by the stylus 404 in FIG. 5A are very distinct on the right side of the test coupon 500 . The line 512 made by the stylus 404 , FIG. 5A with an applied voltage of 200 volts is relatively thin. The line 514 made by the stylus with an applied voltage of 400 volts is thicker and the line 516 made by the stylus with an applied voltage of 600 volts is the thickest line. However, as the lines pass onto the left side of the test coupon 500 , the lines disappear or become faint smudges 520 , 524 . There is no trace of the thinnest line 512 on the left side of the test coupon 500 . There are slight smudges 520 left by the stylus at 400 volts on the left side of the test coupon. The marks made by the stylus at 600 volts on the left side of the test coupon 500 are wider and somewhat better defined but still indistinct when compared to those made on the unprotected right hand side of the test coupon.
A first row of small dots 518 were formed by the ion head 304 using pulse lengths of 50 microseconds and have a diameter between 150 and 200 microns. The second row of larger dots 519 were formed using pulse lengths of 150 microseconds and have a diameter of approximately 250 microns. In contrast to the lines 512 , 514 , 516 , the dot images 518 , 519 are clear and distinct on both the right and left hand portions of the test coupon 500 . This clearly demonstrates that the mesh standoff layer 502 is effective in preventing useful marks from being made with the stylus 404 , FIG. 5A while allowing the ion head 304 , FIG. 5A to print well defined marks.
In conclusion, the incorporation of a standoff layer provides security against undesirable rewriting of electronic paper. This allows the electronic paper to be used in a variety of more secure applications. The implementation of the secure coating is a low cost solution that is readily scalable to large scale production. Further, the standoff layer may also make images on the e-paper more durable and resistant to handling.
The preceding description has been presented only to illustrate and describe examples of the principles described. This description is not intended to be exhaustive or to limit these principles to any precise form disclosed. Many modifications and variations are possible in light of the above teaching.
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An electronic paper device includes a ground plane, a charge receiving layer, and a porous stand off layer disposed over the charge receiving layer. An active layer is interposed between the ground plane and the charge receiving layer, the active layer including a plurality of microcapsules containing charged pigments. A system for writing information to electronic paper is also provided.
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TECHNICAL FIELD
[0001] The present disclosure is directed to systems and methods for washing suspensions of biological cells. More particularly, the present disclosure is directed to systems and methods for washing small volumes of biological cells.
BACKGROUND
[0002] A number of well-known therapies are currently practiced in which a targeted cellular blood component (e.g., red blood cells, white blood cells, and platelets) is separated from whole blood and stored for later infusion to a patient. The targeted cellular product (e.g., red blood cells or platelets) may be in a suspension that includes plasma and/or some other supernatant. As such, it is sometimes desirable to “wash” the cellular suspension (typically with saline) to remove the plasma/supernatant, as well as any non-target cellular material, prior to reinfusion.
[0003] Systems and methods for cell washing are exemplified by US 2013/0341291, US 2013/0092630, and US 2014/0199680, each of which is incorporated herein by reference. Each of these published applications discloses cell washing methods utilizing systems and fluid circuits including a spinning membrane separator. Such systems include peristaltic pumps and pinch valves that act on tubing to direct flow within the fluid circuit.
[0004] The fluid circuits in the cited published applications have a relatively large internal volume, and thus require relatively large volumes of wash or flush media to clear processed fluid through the fluid circuit. While such systems and fluid circuits are capable of washing and reducing the volume of the targeted cellular component into final volumes of ranging from approximately 50 mL to 5,000 mL, there are instances in which smaller final volumes (e.g., 10 mL) are desired, such as when processing single-dose quantities of mononuclear cell products. Thus, it would be desirable to provide systems and methods for washing small volumes of cellular suspensions.
SUMMARY
[0005] In a first aspect of the disclosure, a fluid circuit for cell washing is provided that comprises a spinning membrane separator and a fluid management system comprising a cassette that defines the fluid pathways, and including internal mechanical valving and sensors (for sensing, e.g., pressure, air, fluid interfaces, etc.) for controlling flow through the fluid pathways, thus minimizing the volume of the fluid circuit by minimizing the tubing required. Additionally, the fluid circuit comprises syringes that are acted on by syringe pumps associated with the hardware component of the system to provide pressure for moving fluid through the circuit. Preferably, the syringes are connected directly to the cassette, or the barrels of the syringes may be integrally formed with the cassette, thus further minimizing the volume of the fluid circuit.
[0006] In a second aspect, a disposable kit for washing a suspension of cellular material is provided comprising a spinning membrane separator having an inlet for flowing the suspension of cellular material to be washed and a wash medium into the spinning membrane separator, a first outlet for flowing retentate comprising target components from the spinning membrane separator, and a second outlet for flowing filtrate comprising non-target components of the cellular suspension (including supernatant) and wash medium from the spinning membrane separator. The kit further includes containers for receiving the retentate and the filtrate, and also either includes a container of wash medium integrally connected to the kit or is configured to be connected to a container of wash medium. Alternatively, a sterile vent can replace each of the containers for receiving the retentate and the filtrate. Optionally, the kit may also include either a container of diluent integrally connected to the kit or is configured to be connected to a container of diluent.
[0007] Fluid management of the kit is controlled by a flow control cassette comprising a housing and having a first fluid pathway with a first inlet configured to be in fluid communication with a source of the suspension of cellular material to be washed, a second inlet configured to be in fluid communication with the container of wash medium, and an outlet in fluid communication with the inlet of the spinning membrane separator; a second fluid pathway with an inlet in fluid communication with the first outlet of the spinning membrane separator for flowing retentate, a first outlet in fluid communication with the container for receiving the retentate, and a second outlet in fluid communication with a first syringe; a third fluid pathway with an inlet in fluid communication with the second outlet of the spinning membrane separator for flowing filtrate, a first outlet in fluid communication with the container for receiving the filtrate, and a second outlet in fluid communication with a second syringe; at least one device for selectively occluding the fluid pathways associated with each of the first, second and third fluid pathways; and at least one fluid interface detector associated with each of the first, second and third fluid pathways. Preferably, a device for selectively occluding is associated with each of the first inlet and second inlet of the first fluid pathway, the inlet and first outlet of the second fluid flow pathway, and the inlet and first outlet of the third fluid pathway. Optionally, the second fluid pathway may include a second inlet configured to be in fluid communication with a source of diluent, and a device for selectively occluding is associated with the second inlet.
[0008] In a third aspect, each of the first and second syringe comprises a plunger and a body or barrel having a discharge port, each syringe being removably secured directly to the housing of the cassette by the discharge port.
[0009] In a fourth aspect, a method for washing a suspension of cellular material is provided. The method includes priming various portions of the disposable kit with wash media, loading the spinning membrane separator with a volume of the suspension of cells to be washed, removing the supernatant and non-target materials from the separator, washing the components remaining in the separator, and removing or clearing the washed components from the separator.
[0010] More particularly, the disposable kit may be primed with wash media by withdrawing the plunger of the first syringe while occluding the first fluid pathway adjacent its first inlet, the second fluid pathway adjacent its first outlet, and the third fluid pathway adjacent its inlet to draw wash media into the first fluid pathway; at least partially depressing the plunger of the first syringe while opening the first fluid pathway adjacent its first outlet and occluding the first fluid pathway adjacent its second inlet to prime the first fluid pathway up to the source of the suspension of cellular material to be washed; and further depressing the plunger of the first syringe while opening the second fluid pathway adjacent its first outlet and occluding the first fluid pathway adjacent its inlet to vent air to the container for receiving retentate.
[0011] Alternatively, to further reduce the volume of wash media, the disposable kit may be primed with wash media by drawing wash media from its source only up to the inlet to the first fluid pathway.
[0012] The spinning membrane separator is then loaded with a volume of the suspension of cellular material to be washed by withdrawing the plunger of the first syringe while opening the first fluid pathway adjacent its first inlet and occluding the first fluid pathway adjacent its second inlet, opening the second fluid pathway adjacent its inlet and occluding the second fluid flow path adjacent its first outlet; and occluding the third fluid pathway adjacent its inlet to draw the volume of suspension into the separator; and depressing the plunger of the first syringe while opening the second fluid pathway adjacent its first outlet and occluding the first fluid pathway adjacent its inlet to vent air either to the container for receiving retentate or to the vent filter.
[0013] The volume of the suspension of cells in the separator is then washed by withdrawing the plunger of the second syringe while opening the first fluid pathway adjacent its first inlet and occluding the first fluid pathway adjacent its second inlet, occluding the second fluid pathway adjacent its inlet, and opening the third fluid path way adjacent its inlet and occluding the third fluid flow path adjacent its first outlet to simultaneously draw additional suspension into the separator and supernatant into the second syringe; further withdrawing the plunger of the second syringe while occluding the first fluid pathway adjacent its first inlet and opening the first fluid pathway adjacent its second inlet, occluding the second fluid pathway adjacent its inlet, and occluding the third fluid pathway adjacent its first outlet to draw wash media into and through the spinning membrane separator and into the second syringe.
[0014] The spinning membrane separator is then cleared of washed cells by occluding the third fluid pathway adjacent its inlet and opening the third fluid pathway adjacent its first outlet while depressing the plunger of the second syringe to flow supernatant and wash media into the container for filtrate, and opening the second fluid pathway adjacent its inlet and occluding the second fluid pathway adjacent its first outlet, occluding the first fluid pathway adjacent its first inlet and opening the first fluid pathway adjacent its second inlet while withdrawing the plunger of the first syringe to draw washed cellular matter into the first syringe.
[0015] Washed cellular material may then be flowed from the first syringe to the container for receiving retentate by depressing the plunger of the first syringe while occluding the second fluid pathway adjacent its inlet and opening the second fluid pathway adjacent its first outlet. The steps of loading the spinning membrane separator, washing the volume of cells in the separator, and clearing the spinning membrane of washed cells are repeated until the source of the suspension of cellular material to be washed is emptied.
[0016] Optionally, after the washed cellular material is flowed into the container for receiving retentate, a diluent, such as a cryoprotectant, may be introduced into the collection container for the washed cellular material.
DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a perspective view of a system for washing small volumes of cellular suspensions in accordance with the present invention.
[0018] FIG. 2 is a schematic view of a disposable kit for use in the system of FIG. 1 .
[0019] FIG. 3 is a schematic view of an alternate configuration of the disposable kit of FIG. 2 .
[0020] FIGS. 4-15 are schematic views of the disposable kit of FIG. 2 showing the configuration of the kit during the various stages of a cell washing procedure, with FIGS. 4-6 illustrating the prime phase of the procedure, FIGS. 7-11 illustrating the steps of the first wash phase, and FIGS. 12-15 illustrating the steps of a subsequent wash phase.
[0021] FIG. 16 is a schematic view of a second embodiment of a disposable kit for use in the system of FIG. 1 that permits the addition of a diluent to the washed cells.
[0022] FIGS. 17 and 18 are schematic views of the disposable kit of FIG. 16 illustrating the steps of adding a diluent to the washed cells.
DETAILED DESCRIPTION
[0023] A more detailed description of the systems and methods in accordance with the present disclosure is set forth below. It should be understood that the description below of specific devices and methods is intended to be exemplary, and not exhaustive of all possible variations or applications. Thus, the scope of the disclosure is not intended to be limiting, and should be understood to encompass variations or embodiments that would occur to persons of ordinary skill.
[0024] Turning to FIG. 1 , there is seen a system 10 for cell washing in accordance with the present disclosure including a reusable hardware component 12 and a disposable kit component 14 , best seen in FIG. 2 .
[0025] The disposable kit 14 includes a spinning membrane separator 16 , such as is well known in the art, a cassette 18 , for providing fluid management through the kit, and various containers 20 , 22 , 24 and 26 , and syringes 28 and 30 , each comprising a body or barrel portion and a plunger, in fluid communication with the cassette, which are described in greater detail below. Tubings interconnect each of the various containers, as well as the inlet and outlets of the spinning membrane separator, to the cassette. Preferably the length of each of the interconnecting tubings is kept as short as possible to further minimize the internal volume of the kit. Also, it is preferable that discharge ports of the syringes be configured to be removably connected directly to the cassette, again to minimize the internal volume of the kit. Alternatively, the syringes and/or the spinning membrane separator may be integrally formed as part of the cassette, so as to be internal to the cassette housing, to further reduce the tubing volume associated with the kit.
[0026] The reusable hardware component 12 includes a drive system/support 32 for the spinning membrane separator 16 , supports 34 for the various containers of the disposable kit, a syringe pump 36 , 38 for each syringe 28 , 30 , and a programmable controller 40 for automatically controlling operation of the system.
[0027] Specifically, the disposable kit 14 comprises a spinning membrane separator 16 having an inlet 42 for flowing the suspension of cellular material to be washed and a wash medium into the spinning membrane separator, a first outlet 44 for flowing retentate comprising washed cells from the spinning membrane separator, and a second outlet 46 for flowing filtrate comprising a non-cellular component of the cellular suspension and wash medium from the spinning membrane separator.
[0028] The kit further includes containers 24 , 26 for receiving the retentate and the filtrate, respectively, and also either includes a container 22 of wash medium integrally connected to the kit at the time of manufacture or is configured to be connected to a container of wash medium at the point of use. Alternatively, with reference to FIG. 3 , a sterile vent 48 , 50 can replace each of the containers 24 , 26 for receiving the retentate and the filtrate.
[0029] Fluid management of the kit is controlled by the cassette 18 . The cassette 18 comprises a housing 52 having a series of fluid pathways therein interconnecting the various other components of the disposable kit, each of the fluid pathways having flow control mechanisms, such as valves/clamps and air detectors/pressure sensors associated therewith that are automatically operated by the controller 40 . By having the valves/clamps, detectors and sensors integral with the cassette, the lengths of the tubings interconnecting the various containers of the system to the cassette can be minimized, thus reducing the internal volume of the kit.
[0030] Specifically, the cassette 18 includes a first fluid pathway 54 with a first inlet 56 configured to be in fluid communication with container 20 of the suspension of cellular material to be washed. The first fluid pathway 54 further includes a second inlet 58 is in fluid communication with the container of wash media 20 , and an outlet 60 in fluid communication with the inlet 42 of the spinning membrane separator 16 .
[0031] The cassette 18 includes a second fluid pathway 62 having an inlet 64 in fluid communication with the first outlet 44 of the spinning membrane separator 16 for flowing the retentate. The second fluid pathway further includes a first outlet 66 in fluid communication with the container 24 for receiving the retentate, and a second outlet 68 in fluid communication with the first syringe 28 .
[0032] A third fluid pathway 70 is provided that includes an inlet 72 in fluid communication with the second outlet 46 of the spinning membrane separator 16 for flowing filtrate. The third fluid pathway 70 further includes a first outlet 74 in fluid communication with the container 26 for receiving the filtrate, and a second outlet 76 in fluid communication with the second syringe 30 .
[0033] Devices for selectively occluding the fluid pathways are associated with each of the first, second and third fluid pathways. Such occluding devices may take the form of valves or clamps. Preferably, a first such valve/clamp 78 is associated with the 56 first inlet of the first fluid pathway 54 , a second valve/clamp 80 is associated with the second inlet 58 of the first fluid pathway 54 , a third valve/clamp 82 is associated with the inlet 64 of the second fluid pathway 62 , a fourth valve/clamp 84 is associated with the first outlet 66 of the second fluid flow pathway 62 , a fifth valve/clamp 86 is associated with the inlet 72 of the third fluid pathway 70 , and a sixth valve/clamp 88 is associated with the first outlet 74 of the third fluid pathway 70 .
[0034] Each of the first, second and third fluid pathways is also provided with a sensor 90 , 92 , 94 , respectively, that is able to detect differences in the fluid passing by. Specifically, the sensors 90 , 92 and 94 are able to detect interfaces between different types of fluids, such as an air-liquid interface, a wash media-retentate interface, and a wash media-filtrate interface. Upon the detection of such interfaces, a signal is sent to the controller that will act to control the configuration of the valves/clamps (open or closed) and actuate the syringe pumps 36 , 38 to move fluid through the kit in accordance with a cell washing procedure. The cassette 14 may also include a pressure sensor 96 for monitoring purposes.
[0035] A cell washing procedure utilizing the system set forth above will now be described. The procedure includes three relatively distinct phases: a priming phase, as illustrated in FIGS. 4-6 , during which the kit is primed with wash media, a loading phase, as illustrated in FIGS. 7 and 8 , in which the annulus of the spinning membrane separator is filled with the cellular suspension that is to be washed, and a wash phase, as illustrated in FIGS. 9-11 , in which filtrate (supernatant and wash media) and retentate (the washed cells) are drawn through the cassette and flowed to their respective containers.
[0036] Once the disposable kit 14 is loaded onto the hardware component 12 , with a container 20 of the cell suspension to be washed connected to the cassette 18 , the cell washing procedure may commence. As is appreciated, the procedure is automatically controlled by means of the programmable controller 40 , which sequentially operates the valves/clamps and the syringe pumps, in accordance with signals received from the sensors.
[0037] The priming sequence, as illustrated, comprises three steps. In a first step, shown in FIG. 4 , the first fluid flow path 54 is primed with wash media from the second inlet 58 to the valve/clamp 78 adjacent the first inlet 56 for the source container 20 to the outlet 60 connecting with the inlet 42 of the separator 16 . In this step, the plunger of the first syringe 28 is withdrawn after closing valves/clamps 78 , 84 and 86 and opening valves/clamps 80 and 82 , thus drawing wash media out of the container 22 into the first fluid pathway 54 . Wash media is drawn through the spinning membrane separator 16 and out the first outlet 44 into the second fluid pathway 62 until the sensor 92 detects an air-fluid interface, at which time the syringe pump is stopped and the plunger of the first syringe 28 no longer withdrawn. Alternatively, withdrawal (and depression) of the plunger can be controlled based on changes in volume within the barrel of the syringe that is correlated to volumes of fluid drawn through the kit. As previously noted, the disposable kit may be primed with wash media by drawing wash media from its source 22 only up to the inlet 58 to the first fluid pathway 54 , to further educe the volume of wash media.
[0038] In a second step of the priming sequence, shown in FIG. 5 , the plunger of the first syringe 28 is at least partially depressed, after opening valve/clamp 78 and closing valve/clamp 80 , to prime the first fluid pathway 54 to the source container 20 , thus completing the priming of the first fluid pathway.
[0039] In a third step of the priming sequence, shown in FIG. 6 , the plunger of the first syringe 28 is completely depressed, so that no air remains in the syringe, after closing valves/clamps 78 and 82 and opening valve/clamp 84 , to vent air to the retentate container 24 . While not shown in the drawings, the third fluid flow path 70 may also be primed with wash media by withdrawing the plunger of the second syringe 30 after valves/clamps 78 , 82 and 88 are closed and valves/clamps 80 and 86 opened, to draw wash media into the third fluid pathway. The air drawn into the second syringe 30 would then be vented into the filtrate container 26 by closing valve/clamp 86 and opening valve/clamp 88 and completely depressing the plunger.
[0040] The system is now ready for loading the annulus of the spinning membrane separator 16 with the suspension of cells to be washed. With reference to FIG. 7 , this is accomplished by withdrawing the plunger of the first syringe 28 after opening valves/clamps 78 and 82 and closing valve/clamp 84 . This draws cell suspension out of the source container 20 into the first fluid pathway 54 and into the spinning membrane separator 16 . The wash media in the first fluid pathway 54 that resulted from priming is drawn into the second fluid pathway. The withdrawal of the plunger of the first syringe 28 is stopped when the annulus of the separator 16 is filled with cell suspension, and prior to the cell suspension reaching the second fluid pathway, as determined by, e.g., detection of an air-fluid interface by sensor 92 , or upon a change in volume of the barrel of the syringe. The air drawn into the syringe 28 due to loading the separator 16 is then vented to the retentate container 24 by completely depressing the plunger of the first syringe 28 after closing the valve/clamp 82 and opening the valve/clamp 84 , as shown in FIG. 8 .
[0041] The supernatant is then separated from the cell suspension by the separator 16 and removed. With reference to FIG. 9 , this is accomplished by withdrawing the plunger of the second syringe 30 after opening valves/clamps 78 and 86 , while valves/clamps 80 , 82 and 88 remain closed. As such, additional cell suspension is drawn into the separator as the supernatant flows out of the separator through outlet 46 , into the third fluid flow path 70 and into the barrel of the second syringe 30 , while cellular content accumulates in the annulus of the separator.
[0042] Withdrawal of the plunger of the second syringe 30 continues drawing supernatant into the barrel until the cellular content of the annulus of the separator 16 is exceeds the configured volume (based on an empirical determination of the internal volume of the spinner annulus, the rotational velocity of the spinner, the filtrate flow rate). Alternatively, the plunger of the second syringe 30 continues to draw supernatant into the barrel of the second syringe 30 until it is filled with supernatant, or the sensor 90 detects an air fluid interface, indicating that the source container 20 is empty.
[0043] The cells accumulated in the annulus of the separator 16 are then washed. With reference to FIG. 10 , this is accomplished by further withdrawing the plunger of the second syringe 30 after closing valve/clamp 78 and closing valve/clamp 80 , while valves/clamps 82 , 84 and 88 remain closed. As such, wash media is drawn into and through the separator 16 into the second syringe 30 . The plunger of the syringe continues to be withdrawn until it is either filled or container 22 is emptied of wash media.
[0044] The cells accumulated in the annulus of the separator 16 are then withdrawn to clear the annulus. With reference to FIG. 11 , to this end, the plunger of the first syringe 28 is withdrawn after opening valve/clamp 82 and closing valve/clamp 86 , while valves/clamps 78 and 84 are closed, thus drawing the washed cells into the barrel of the first syringe.
[0045] If the source container 20 contains additional cell suspension that is to be washed, the supernatant/wash media contained in the second syringe can be flowed into the filtrate container 26 by depressing the plunger of the second syringe after the valve/clamp 86 is closed and the valve/clamp 88 opened.
[0046] If additional cell suspension is contained in the source container 20 , it can be washed by repeating the steps illustrated in FIGS. 9-11 , as described above, until the container 20 is depleted. At the completion of each wash cycle, the washed cells contained in the first syringe 28 may be flowed to the retentate container 24 by fully depressing the plunger of the first syringe 28 after opening valve/clamp 84 and closing valve/clamp 82 .
[0047] Alternatively, subsequent wash cycles may be performed as illustrated in FIGS. 12-15 . Specifically, a second or subsequent volume of cell suspension is pulled from the source container 20 into the annulus of the separator 16 by closing the valves/clamps 80 , 82 and 88 , opening the valves/clamps 78 and 86 , and withdrawing the plunger of second syringe 30 ( FIG. 12 ). At the same time, the previous cycle's washed retentate is dumped into the retentate container 24 by opening the valve/clamp 84 and depressing the plunger of the first syringe 28 .
[0048] Then, with reference to FIG. 13 , the supernatent in the cell suspension is removed by closing the valve/clamp 78 and opening the valve/clamp 80 , so that additional wash media is drawn from the container 22 into the annulus of the spinner 16 by further withdrawing the plunger of the second syringe 30 .
[0049] Then, the annulus of the spinner 16 is cleared by opening the valve/clamp 82 and withdrawing the plunger of the first syringe 28 , thus drawing the retentate into the syringe 28 ( FIG. 14 ). Simultaneously, the filtrate in the second syringe 30 is flowed into the filtrate container 28 by closing the valve/clamp 86 and depressing the plunger of the second syringe 30 .
[0050] The retentate in the first syringe 28 is then flowed to the retentate container 24 by closing the valves/clamps 80 , 82 , opening the valve/clamp 84 , and depressing the plunger of the first syringe 28 , as shown in FIG. 15 . The steps illustrated in FIGS. 12-15 may be repeated until the source container 20 is emptied of cell suspension.
[0051] Under certain circumstances, it may be desirable to dilute the washed cells comprising the retentate, for example if the retentate is to be frozen, in which case a cryoprotective agent would be used to dilute the retentate, To this end, and as illustrated in FIG. 16 , the cassette 18 may be provided with a further, fourth fluid pathway 100 that provides fluid communication between the first syringe 28 and a container 102 for the diluent. The fluid pathway 100 includes an inlet 104 and a valve/clamp 106 adjacent the inlet 104 for controlling fluid flow through the pathway 100 .
[0052] To add a diluent to the retentate in the container 24 , the valves/clamps 82 and 84 are closed, while the valve/clamp 106 is opened. The plunger of the first syringe 28 is withdrawn to flow diluent out of the container 102 and into the syringe 28 (as shown in FIG. 17 . Then, the valve/clamp 106 is closed and the valve/clamp 84 opened. The plunger of the first syringe 28 is then depressed to flow diluent into container 24 (as shown in FIG. 18 ).
[0053] Thus, an improved method and system for washing small volumes of biological cells has been disclosed. The description provided above is intended for illustrative purposes, and is not intended to limit the scope of the disclosure to any particular method, system, apparatus or device described herein.
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A fluid circuit for cell washing is provided that comprises a spinning membrane separator and a fluid management system comprising a cassette that defines the fluid pathways, and including internally mechanical valving, pressure sensing and air sensing for controlling flow through the fluid pathways, thus minimizing the volume of the fluid circuit. Additionally, the fluid circuit comprises syringes that are acted on by syringe pumps associated with the hardware component of the system to provide pressure for moving fluid through the circuit. Preferably, the syringes are connected directly to the cassette, or formed integrally within the cassette housing, thus further minimizing the volume of the fluid circuit.
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CROSS-REFERENCE TO RELATED APPLICATION
Cross-reference is hereby made to commonly-assigned related U.S. Pat. No. 6,832,478, issued on Dec. 21, 2004, to David Anderson, et al., entitled “Shape Memory Alloy Actuators”.
FIELD OF THE INVENTION
Embodiments of the present invention relate generally to shape memory alloy (SMA) actuators and more particularly to means for forming SMA actuators and incorporating such actuators into elongated medical devices.
BACKGROUND
The term SMA is applied to a group of metallic materials which, when subjected to appropriate thermal loading, are able to return to a previously defined shape or size. Generally an SMA material may be plastically deformed at some relatively low temperature and will return to a pre-deformation shape upon exposure to some higher temperature by means of a micro-structural transformation from a flexible martensitic phase at the low temperature to an austenitic phase at a higher temperature. The temperature at which the transformation takes place is known as the activation temperature. In one example, a TiNi alloy has an activation temperature of approximately 70° C. An SMA is “trained” into a particular shape by heating it well beyond its activation temperature to its annealing temperature where it is held for a period of time. In one example, a TiNi alloy is constrained in a desired shape and then heated to 510° C. and held at that temperature for approximately fifteen minutes.
In the field of medical devices SMA materials, for example TiNi alloys, such as Nitinol, or Cu alloys, may form a basis for actuators designed to impart controlled deformation to elongated interventional devices. Examples of these devices include delivery catheters, guide wires, electrophysiology catheters, ablation catheters, and electrical leads, all of which require a degree of steering to access target sites within a body; that steering is facilitated by an SMA actuator. An SMA actuator within an interventional device typically includes a strip of SMA material extending along a portion of a length of the device and one or more resistive heating elements through which electrical current is directed. Each heating element is attached to a surface of the SMA strip, in proximity to portions of the SMA strip that have been trained to bend upon application of thermal loading. A layer of electrically insulating material is disposed over a portion of the SMA strip on which a conductive material is deposited or applied in a trace pattern forming the heating element. Electrical current is directed through the conductive trace from wires attached to interconnect pads that terminate each end of the trace. In this way, the SMA material is heat activated while insulated from the electrical current. It is important that, during many cycles of activation, the insulative layer does not crack or delaminate from the surface of the SMA strip.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a plan view including a partial section of an elongated medical device including an SMA actuator.
FIG. 1B is a plan view of the exemplary device of FIG. 1A wherein a current has been passed through heating elements of the SMA actuator.
FIG. 1C is a plan view including a partial section of another embodiment of an elongated medical device including an SMA actuator.
FIG. 1D is a plan view of the exemplary device of FIG. 1C wherein a current has been passed through heating elements of the SMA actuator.
FIG. 2A is a perspective view of an SMA substrate or strip that would be incorporated in an SMA actuator.
FIG. 2B is a plan view of a portion of a surface of an SMA actuator.
FIG. 3 is a section view through a portion of an SMA actuator according an embodiment of the present invention.
FIG. 4 is a section view through a portion of an SMA actuator according to an alternate embodiment of the present invention.
FIGS. 5A-D are section views illustrating steps, according to embodiments of the present invention, for forming the SMA actuator illustrated in FIG. 4 .
DETAILED DESCRIPTION
FIGS. 1A-D illustrate two examples of elongated medical devices each incorporating an SMA actuator, wherein each actuator serves to control deformation of a portion of each device. FIG. 1A is a plan view with partial section of an elongated medical device 300 including an SMA actuator 56 . As illustrated in FIG. 1A , medical device 300 further includes a shaft 305 , a hub 303 terminating a proximal end of shaft 305 , and conductor wires 57 coupled to SMA actuator 56 . SMA actuator 56 , positioned within a distal portion 100 of shaft 305 , includes a plurality of heating elements (not shown), electrically insulated from an SMA substrate, through which current flows fed by wires 57 ; wires 57 , extending proximally and joined to electrical contacts (not shown) on hub 303 , carry current to heat portions of the SMA substrate to an activation temperature. At the activation temperature, portions of the SMA substrate revert to a trained shape, for example a shape 200 as illustrated in FIG. 1B . FIG. 1B is a plan view of the exemplary device 300 of FIG. 1A wherein a current has been passed through heating elements of SMA actuator 56 , locations of which heating elements correspond to bends 11 , 12 , and 13 . When the current is cut, either an external force or a spring element (not shown) joined to shaft 605 in proximity of SMA actuator 56 returns distal portion 100 back to a substantially straight form as illustrated in FIG. 1A . Device 300 , positioned within a lumen of another elongated medical device, may be used to steer or guide a distal portion of the other device via controlled deformation of actuator 56 at locations corresponding to bends 11 , 12 , and 13 , either all together, as illustrated in FIG. 1B , or individually, or in paired combinations.
FIG. 1C is a plan view including a partial section of another embodiment of an elongated medical device 600 including an SMA actuator 10 embedded in a portion of a wall 625 of a shaft 605 . As illustrated in FIG. 1C , medical device 600 further includes a hub 603 terminating a proximal end of shaft 605 , a lumen 615 extending along shaft 605 , from a distal portion 610 through hub 603 , and conductor wires 17 coupled to SMA actuator 10 . SMA actuator 10 , positioned within distal portion 610 of shaft 605 , includes a plurality of heating elements (not shown), electrically insulated from an SMA substrate, through which current flows fed by wires 17 ; wires 17 , extending proximally and joined to electrical contacts (not shown) on hub 603 , carry current to heat portions of the SMA substrate to an activation temperature. At the activation temperature, portions of the SMA substrate revert to a trained shape, for example a bend 620 as illustrated in FIG. 1D . FIG. 1D is a plan view of the exemplary device 600 of FIG. 1C wherein a current has been passed through a heating element of SMA actuator 10 , a location of which heating element corresponds to bend 620 . When the current is cut, either an external force or a spring element (not shown), for example embedded in a portion of shaft wall 625 , returns distal portion 610 back to a substantially straight form as illustrated in FIG. 1C . Lumen 615 of device 600 , may form a pathway to slideably engage another elongated medical device, guiding the other device via controlled deformation of distal portion 610 by actuator 10 resulting in bend 620 .
FIGS. 2A-B illustrate portions of exemplary SMA actuators that may be incorporated into an elongated medical device, for example device 300 illustrated in FIGS. 1A-B . FIG. 2A is a perspective view of an SMA substrate or strip 20 that would be incorporated into an SMA actuator, such as SMA actuator 56 illustrated in FIG. 1A . Embodiments of the present invention include an SMA substrate, such as strip 20 , having a thickness between approximately 0.001 inch and approximately 0.1 inch; a width and a length of strip 20 depends upon construction and functional requirements of a medical device into which strip 20 is integrated. As illustrated in FIG. 2A strip 20 includes a surface 500 , which according to embodiments of the present invention includes a layer of an inorganic electrically insulative material formed or deposited directly thereon, examples of which include oxides such as silicon oxide, titanium oxide, or aluminum oxide, nitrides such as boron nitride, silicon nitride, titanium nitride, or aluminum nitride, and carbides such as silicon carbide, titanium carbide, or aluminum carbide. Means for forming the inorganic material layer are well know to those skilled the art and include vacuum deposition methods, such as sputtering, evaporative metalization, plasma assisted vapor deposition, or chemical vapor deposition; other methods include precipitation coating and printing followed by sintering. In an alternate embodiment an SMA substrate, such as strip 20 , is a TiNi alloy and a native oxide of the TiNi alloy forms the layer of inorganic electrically insulative material; the native oxide may be chemically, electrochemically or thermally formed on surface 500 . In yet another embodiment, a deposited non-native oxide, nitride, or carbide, such as one selected from those mentioned above, in combination with a native oxide forms the layer of electrically insulative material on surface 500 .
According to embodiments of the present invention, an SMA substrate, such as strip 20 , is trained to bend, for example in the direction indicated by arrow A in FIG. 2A , after deposition or formation of an inorganic electrically insulative layer upon surface 500 , since the inorganic insulative layer will not break down under training temperatures. Training temperatures for TiNi alloys range between approximately 300° C. and approximately 800° C. Alternately an SMA substrate, such as strip 20 , may be trained to bend before deposition or formation of the inorganic insulative layer if a temperature of the substrate, during a deposition or formation process, is maintained below an activation temperature of the substrate. Furthermore, according to an alternate embodiment, an additional layer of an organic material is deposited over the inorganic layer to form a composite electrically insulative layer. Examples of suitable organic materials include polyimide, parylene, benzocyclobutene (BCB), and fluoropolymers such as polytetrafluoroethylene (PTFE). Means for forming the additional layer are well known to those skilled in the art and include dip coating, spay coating, spin coating, chemical vapor deposition, plasma assisted vapor deposition and screen printing; the additional layer being formed following training of the SMA substrate and at a temperature below an activation temperature of the substrate. An activation temperature for an SMA actuator included in an interventional medical device must be sufficiently high to avoid accidental activation at body temperature; a temperature threshold consistent with this requirement and having a safety factor built in is approximately 60° C. This lower threshold of approximately 60° C. may also prevent accidental activation during shipping of the medical device. An activation temperature must also be sufficiently low to avoid thermal damage to body tissues and fluids; a maximum temperature consistent with this requirement is approximately 100° C., but will depend upon thermal insulation and, or cooling means employed in a medical device incorporating an SMA actuator.
FIG. 2B is a plan view of a portion of a surface of an SMA actuator 50 . FIG. 2B illustrates a group of conductive trace patterns; portions of the conductive trace patterns are formed either on a first layer, a second layer, or between the first and second layer of a multi-layer electrical insulation 1 formed on a surface of an SMA substrate, such as strip 20 illustrated in FIG. 2A . As illustrated in FIG. 2B , conductive trace pattern includes heating element traces 2 , which are formed on first layer of insulation 1 , signal traces 4 , 5 , which are formed on second layer of insulation 1 , and conductive vias 3 , 9 , which traverse second layer in order to electrically couple heating element signal traces 2 on first layer with signal traces 4 , 5 on second layer. Each signal trace 4 extends from an interconnect pad 6 through via 3 to heating element trace 2 , while signal trace 5 extends from all heating element traces 2 through vias 9 to a common interconnect pad 7 . According to embodiments of the present invention, multi-layer insulation 1 is formed of an inorganic electrically insulative material, examples of which are presented above, deposited or formed directly on the SMA substrate. Portions of conductive trace pattern deposited upon each layer of multi-layer insulation 1 , according to one embodiment, are formed of a first layer of titanium, a second layer of gold and a third layer of titanium and each interconnect pad 6 , 7 is formed of gold deposited upon the second layer of insulation 1 . Details regarding pattern designs, application processes, thicknesses, and materials of conductive traces that may be included in embodiments of the present invention are known to those skilled in the arts of VLSI and photolithography.
Section views in FIGS. 3 and 4 illustrate embodiments of the present invention in two basic forms. FIG. 3 is a section view through a portion of an SMA actuator 30 including one segment of a conductive trace 32 that may be a portion of a heating element trace, such as a heating element trace 2 illustrated in FIG. 2B . As illustrated in FIG. 3 , SMA actuator 30 further includes an SMA substrate 350 , a first insulative layer 31 , electrically isolating conductive trace 32 from SMA substrate 350 , and a second insulative layer 33 covering and surrounding conductive trace 32 to electrically isolate conductive trace 32 from additional conductive traces that may be included in a pattern, such as the pattern illustrated in FIG. 2B . According to embodiments of the present invention, first insulative layer 31 , including an inorganic material, is deposited or formed directly on substrate 350 , as described in conjunction with FIG. 2A . Conductive materials are deposited or applied on insulative layer 31 , creating conductive trace 32 , for example by etching, and then second insulative layer 33 , including an inorganic material, is deposited or applied over conductive trace 32 . In an alternate embodiment, second insulative layer 33 includes an organic electrically insulative material; examples of suitable organic materials include polyimide, parylene, benzocyclobutene (BCB), and fluoropolymers such as polytetrafluoroethylene (PTFE). Means for forming insulative layer 33 include dip coating, spray coating, spin coating, chemical vapor deposition, plasma assisted vapor deposition and screen-printing. Training of SMA substrate 350 may follow or precede formation of first insulative layer 31 , as previously described in conjunction with FIG. 2A .
FIG. 4 is a section view through a portion of an SMA actuator 40 including one segment of a conductive trace 42 . According to alternate embodiments of the present invention, a groove in a surface of an SMA substrate 450 (reference FIG. 5A ) establishes a pattern for conductive trace 42 , the pattern including a heating element trace disposed between signal traces, similar to one of heating element traces 2 and corresponding signal traces 4 , 5 illustrated in FIG. 2B . As illustrated in FIG. 4 , an insulative layer 41 is disposed between conductive trace 42 and SMA substrate 450 electrically isolating conductive trace 42 from an SMA substrate 450 . According to embodiments of the present invention, insulative layer 41 includes an inorganic material, examples of which are given in conjunction with FIG. 2A , formed directly on SMA substrate 450 . Training of SMA substrate 450 may follow or precede formation of first insulative layer 41 including an inorganic material, as previously described in conjunction with FIG. 2A . According to alternate embodiments of the present invention, insulative layer 41 includes an organic material, formed directly on SMA substrate 450 following training of substrate 450 . Selected organic materials for insulative layer 41 include those which may be deposited or applied at a temperature below an activation temperature of SMA substrate 450 and those which will not degrade at the activation temperature of SMA substrate 450 ; examples of such materials include polyimide, parylene, benzocyclobutene (BCB), and fluoropolymers such as polytetrafluoroethylene (PTFE). Means for forming insulative layer 41 include dip coating, spray coating, spin coating, chemical vapor deposition, plasma assisted vapor deposition and screen-printing.
FIGS. 5A-D are section views illustrating steps, according to embodiments of the present invention, for forming SMA actuator 40 illustrated in FIG. 4 . FIG. 5A illustrates SMA substrate 450 including a groove 510 formed in a surface 515 ; groove 510 is formed, for example by a machining process. FIG. 5B illustrates a layer of electrically insulative material 511 formed on surface 515 and within groove 510 . FIG. 5C illustrates a layer of conductive material 512 formed over layer of insulative material 511 . FIG. 5D illustrates insulative layer 41 and conductive trace 42 left in groove 510 after polishing excess insulative material 511 and conductive material 512 from surface 515 . As illustrated in FIG. 5D , conductive trace 42 is flush with surface 515 following polishing; in one example, according to this embodiment, groove 510 is formed having a width of approximately 25 micrometer and a depth of approximately 1.2 micrometer approximately matching a predetermined combined thickness of insulative layer 41 and conductive trace 42 . According to alternate embodiments of the present invention, groove 510 is formed deeper than a resultant combined thickness of the insulative layer 41 and conductive trace 42 so that conductive trace is recessed from surface 515 .
EXAMPLES
Minimum theoretical thicknesses having sufficient dielectric strength for operating voltages of 100V, 10V, and 1V applied across conductive traces on SMA actuators were calculated for insulating layers of Silicon Nitride, Aluminum Nitride, Boron Nitride, and polyimide according to the following formula:
Thickness=voltage/dielectric strength.
A dielectric strength for Silicon Nitride was estimated to be 17700 volts/millimeter; a dielectric strength for Aluminum Nitride was estimated to be 15,000 volts/millimeter; a dielectric strength for Boron Nitride was estimated to be 3,750 volts/millimeter; a dielectric strength for polyimide was estimated to be 157,500 volts/millimeter. Results are presented in Table 1.
TABLE 1
Thickness, 100 V
Thickness, 10 V
Thickness, 1 V
(micrometer)
(micrometer)
(micrometer)
Silicone Nitride
5.65
0.56
0.06
Aluminum
6.67
0.67
0.07
Nitride
Boron Nitride
26.7
2.67
0.27
Polyimide
0.64
0.064
0.0064
Finally, it will be appreciated by those skilled in the art that numerous alternative forms of SMA substrates and trace patterns included in SMA actuators and employed in medical devices are within the spirit of the present invention. For example, SMA actuators according to the present invention can include conductive trace patterns on two or more surfaces of an SMA substrate or an additional layer or layers of non-SMA material joined to an SMA substrate, which serve to enhance biocompatibility or radiopacity in a medical device application. Hence, descriptions of particular embodiments provided herein are intended as exemplary, not limiting, with regard to the following claims.
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A shape memory alloy (SMA) actuator includes a groove formed in a surface of a shape memory alloy (SMA) substrate establishing a trace pattern for a layer of conductive material formed over an electrically insulative layer. The trace pattern includes a first end, a second end, and a heating element disposed between the first and second ends. The SMA substrate is trained to deform at a transition temperature achieved when electricity is conducted through the conductive material via first and second interconnect pads terminating the first and second ends of the trace pattern.
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BACKGROUND
The present invention relates to a system which monitors for smart grid power outages and restorations.
Utility companies are in the business of reliably delivering power to their customers. Currently, utility companies rely on their customers to inform them of power outages or use some high level monitoring system.
SUMMARY
Relying on customers to report power outages is error-prone and results in inherent delays in understanding the true state of power outages on the grid. Current high level monitoring systems experience adverse network conditions such as dropped, out-of-order and duplicate outage messages, and therefore cannot accurately determine power outages. The power outage detection system for smart grids accurately determines power outages and restorations for smart grid devices under adverse network conditions in which messages may be dropped, arrive out-of-order, or are duplicated using a finite state machine.
In one embodiment, the invention provides a power outage detection system. The system includes a device configured to increment a reboot counter when the device is powered up, and to transmit a first message when the device loses power and a second message when the device is powered up, and a back office system. The first message includes the value of the reboot counter and a timestamp, and the second message includes the value of the reboot counter. The back office system includes a finite state machine configured to receive the first and second messages. The finite state machine determines if the received first message is valid using the value of the reboot counter and the timestamp, and determines if the received second message is valid using the value of the reboot counter. The finite state machine then outputs an accurate indication of the state of the device.
In another embodiment the invention provides a method of determining a state of a device based on a message received from the device. The method includes receiving a message from the device, the message having a first type including a reboot counter and a timestamp or a second type including the reboot counter, transitioning the state of the device from online to momentary when a valid first type message is received and a difference between the timestamp and the current time is less than a predefined time duration, transitioning the state of the device from momentary to online when a valid second type message is received, transitioning the state of the device from momentary to sustained when the difference between the timestamp and the current time exceeds a predefined time duration without receiving a valid second type message, transitioning the state of the device from sustained to momentary when a valid first type message is received and a difference between the timestamp and the current time is less than a predefined time duration, and transitioning the state of the device from sustained to online when a valid second type message is received.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of an outage detection system.
FIG. 2 is a block diagram of a back office computer of an outage detection system.
FIG. 3 is a block diagram of a finite state machine of an outage detection system.
FIG. 4 is a flow chart of a finite state machine.
DETAILED DESCRIPTION
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
FIG. 1 illustrates an outage detection system 100 . The outage detection system 100 includes a plurality of devices (e.g., meters) 105 , a wireless mesh network 106 , an access point 110 , and a back office system 114 . The back office system 114 includes a back office computer 115 , an outage processing system 120 , and a registrar 121 . The back office system 114 can be one system incorporating the outage processing system 120 , the registrar 121 , and/or the back office computer 115 , or the outage processing system 120 , the registrar 121 , and the back office computer 115 can all be separate systems. While reference is made herein to an electric utility and a utility grid for power distribution, it should be understood that the systems and methods described herein can also or alternatively be used with other utilities, such as, for example, water, gas, and/or other measurable and widely distributed services. In addition, the system and method can be used with other instrumented electrical devices (e.g., street lights).
FIG. 2 illustrates the back office computer 115 of the back office system 114 . The back office computer 115 includes a processor 150 (e.g., a microprocessor, microcontroller, ASIC, DSP, FPGA, etc) and memory 155 (e.g., flash, ROM, RAM, EEPROM, etc.), which can be internal to the processor 150 , external to the processor 150 , or a combination thereof. The memory 155 stores the software used for the outage detection system, while the processor 150 executes the stored software. The back office system 114 also includes an input/output interface 160 and a clock 165 .
Referring back to FIG. 1 , when a meter 105 powers on, it attempts to register with an access point 110 , which will assign the meter 105 an IPv6 address and forward a registration message to the registrar 121 of the back office system 114 . The outage processing system 120 receives the meter registration message containing the registration timestamp from the registrar 121 after a delay. In the embodiment shown, the registrar 121 acts as a Domain Name Server (DNS).
The back office system 114 also uses ping requests to regularly determine if a meter 105 is powered on. The back office system 114 sends a ping request to a meter 105 . A positive ping response received by the back office system 114 indicates that the meter 105 is powered on. A negative ping response does not necessarily indicate that the meter 105 is powered off. A negative ping response could also mean network problems due to route instability or registration of meters 105 not yet complete or the ping request or response was dropped by the network due to congestion. Each ping response includes a timestamp.
When a meter 105 loses power, the meter 105 sends a first message indicating it has lost power to the back office computer 115 via the mesh network 106 . This message is known as a last gasp message and contains a timestamp of when the last gasp message was sent. That is, the meter 105 sends the last gasp to neighboring meters 105 that still have power. The neighboring meters 105 receive the last gasp message and forward it to the access point 110 . The access point 110 then forwards the message to the back office computer 115 .
The back office computer 115 receives and processes the last gasp message, determining if the last gasp message is valid. Examples of invalid messages include messages received multiple times, delayed messages, etc. Once a last gasp message is determined to be valid the back office system 115 determines a state of the meter 105 , and forwards the state to the outage processing system 120 , the outage processing system 120 keeps track of all the meters 105 within the wireless mesh network 106 .
When power is restored to a meter 105 , the meter 105 sends a second message known as a restoration message to the access point 110 , via the wireless mesh network 106 . The access point 110 then sends the message to the back office computer 115 . The back office system 114 again determines if the message is valid. Once a restoration message is determined to be valid the back office system 115 determines a state of the meter 105 , and forwards the state to the outage processing system 120 .
Messages are determined to be valid by using a reboot counter, timestamps of the last gasp messages, and the current time. The reboot counter indicates the number of reboots that the meter 105 has performed since installation. After each power on, the meter's reboot counter is incremented. The timestamps indicate the outage times. A last gasp message followed by a restoration message with an incremented reboot count produces a typical outage and restoration scenario. A momentary outage occurs when the time between the timestamp of a last gasp message and the current time is less than a predefined value (e.g., 5 minutes), also known as a momentary filter duration. An outage is considered a sustained outage when the time difference between the timestamp of the last gasp message and the current time is greater than the momentary filter duration. When a restoration message is received with the same or lower reboot count, the restoration message is a duplicate or is late. When a restoration message is received with a reboot count higher than expected, there are dropped or out-of-order messages.
FIG. 3 shows a Finite State Machine (FSM) 200 used to keep track of the state of the meters 105 . The FSM 200 is implemented using a computer program, stored in the memory 155 and executed by the processor 150 . A different FSM 200 is created for each meter 105 . The back office computer 115 sends the determined state for each meter 105 to the outage processing system 120 , which records the state and determines whether an outage has occurred and the extent of the outage.
The FSM 200 contains a last gasp register 201 , a restoration register 202 , and a current state register 203 . The last gasp register 201 will only be updated when the FSM 200 receives a last gasp message with a higher reboot count then the previously received last gasp message. A last gasp message with the same or lower reboot count than the previously received last gasp message will not update the last gasp register 201 . The same logic applies to the restoration register 202 for restoration messages. The clock 165 has the current time for comparison against the timestamps of the last gasp messages. The current state register 203 keeps track of the current state of the meter 105 , and is updated upon the meter 105 transitioning to a new state.
FIG. 4 illustrates the states of the FSM 200 , including an online state 205 , a momentary state 210 , a sustained state 215 , and the transitions from one state to another. A meter 105 is in the online state 205 if power is not lost. A meter 105 is in the momentary state 210 if the meter 105 has an outage that has not yet lasted more than the momentary filter duration. A meter 105 is in the sustained state 215 if power remains out for more than the momentary filter duration.
When the meter 105 is powered on it is in the online state 205 . When a last gasp message with a reboot count greater or equal to the restoration register 202 is received by the back office system 114 , the meter 105 transitions to the momentary state 210 if the difference between the timestamp of the received last gasp message and the current time is less than a predefined time period (i.e., a momentary filter duration) (transition 220 ). If a restoration message with a reboot count greater than the last gasp register 201 is received by the back office system 114 , the meter 105 transitions from the momentary state 210 back to the online state 205 (transition 225 ).
When the meter 105 is in the momentary state 210 , a transition to the online state 205 occurs when a DNS registration message, or a ping response from the meter 105 , has a timestamp more recent than the timestamp of the most recent valid last gasp message (transition 225 ). When the meter 105 is in the momentary state 210 , a transition to the sustained state 215 occurs when the difference between the timestamp of the most recent valid last gasp message and the current time is greater than the momentary filter duration (transition 230 ). The meter 105 transitions from the sustained state 215 back to the momentary state 210 if a new last gasp message with a reboot count greater than the last gasp register 201 is received and the momentary filter duration has not yet occurred (transition 235 ).
When the meter 105 is in the sustained state 215 , a transition to the online state 205 occurs when a restoration message with a reboot count greater than the last gasp register 201 is received (transition 240 ). When the meter 105 is in the sustained state 215 , a transition to the online state 205 also occurs when a DNS registration message, or a ping response from the meter 105 , is received with a timestamp more recent than the timestamp of the most recent valid last gasp message (transition 240 ).
When the meter 105 is in the online state 205 , a transition to the sustained state 215 occurs when a last gasp message with a reboot count greater than or equal to the restoration register 202 is received having a difference between the timestamp of the message received and the current time greater than the momentary filter duration (transition 245 ).
Scenarios occur that do not change the current state of the meter 105 . If the current state is the online state 205 , the meter 105 will stay in the online state if a last gasp message is received having a reboot count less than the previous restoration register 202 . The meter 105 will also stay in the online state 205 if a new restoration message is received.
If the current state is the momentary state 210 , the meter 105 stays in the momentary state 210 if a last gasp message having a reboot count greater than the last gasp register 201 is received and the difference between the timestamp of the message and the current time is less than the momentary filter duration. The meter 105 also stays in the momentary state 210 when a last gasp message having a reboot count less than or equal to the last gasp register 201 is received. The meter 105 also stays in the momentary state 210 when a restoration message is received with a reboot count less than or equal to the last gasp register 201 .
If the current state is the sustained state 215 , the meter 105 stays in the sustained state 215 if a last gasp message is received with a reboot count greater than the last gasp register 201 , and the difference between the timestamp of the message and the current time is greater than the momentary filter duration. The meter 105 stays in the sustained state 215 if a last gasp message is received with a reboot count less than or equal to the last gasp register 201 . The meter 105 stays in the sustained state 215 if a restoration message is received with a reboot count less than or equal to the last gasp register 201 .
The table below illustrates the start state, end state, triggering event, and the corresponding transitions of FIG. 4 , as described above. The triggering event is represented in Boolean language, using last gasp message (LG), restoration message (RS), last gasp register (LG_R), restoration register (RS_R), and momentary filter duration (MF). For example, transition 220 , having an online start state and momentary end state, has a triggering event of LG(>=RS_R &&<MF). This means that the state will transition from the online state 205 to the momentary state 210 when a last gasp message (LG) is received that has a reboot count greater than or equal to the registration register 202 (RS_R), and the last gasp message (LG) has a time difference between the timestamp of the message and the current time that is less than the momentary filter duration (MF).
Start State
End State
Triggering Event
Transition
Online
Momentary
LG(>=RS_R && <MF)
Transition 220
Online
Online
LG < RS_R
No Transition
Online
Online
RS <= RS_R
No Transition
Online
Online
RS > RS_R
No Transition
Online
Sustained
LG(>=RS_R && >MF)
Transition 245
Momentary
Online
RS > LG_R
Transition 225
Momentary
Online
Meter registration
Transition 225
timestamp more
recent that most
recent valid last
gasp message
timestamp
Momentary
Online
Ping response
Transition 225
timestamp more
recent that most
recent valid last
gasp message
timestamp
Momentary
Momentary
RS <= LG_R
No Transition
Momentary
Momentary
LG <= LG_R
No Transition
Momentary
Momentary
LG(>LG_R && <MF)
No Transition
Momentary
Sustained
LG > MF
Transition 230
Sustained
Online
RS > LG_R
Transition 240
Sustained
Online
Meter registration
Transition 240
timestamp more
recent that most
recent valid last
gasp message
timestamp
Sustained
Online
Ping response
Transition 240
timestamp more
recent that most
recent valid last
gasp message
timestamp
Sustained
Momentary
LG(>LG_R && <MF)
Transition 235
Sustained
Sustained
LG <= LG_R
No Transition
Sustained
Sustained
RS <= LG_R
No Transition
Sustained
Sustained
LG(>LG_R && >MF)
No Transition
Thus, the invention provides, among other things, a system and method for monitoring smart grid power outages and restorations under adverse network conditions in which messages may be dropped, arrive out-of-order, or duplicated. Various features and advantages of the invention are set forth in the following claims.
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A power outage detection system. The system includes a device configured to increment a reboot counter when the device is powered up, and to transmit a first message when the device loses power and a second message when the device is powered up, and a back office system. The first message includes the value of the reboot counter and a timestamp, and the second message includes the value of the reboot counter. The back office system includes a finite state machine configured to receive the first and second messages. The finite state machine determines if the received first message is valid using the value of the reboot counter and the timestamp, and determines if the received second message is valid using the value of the reboot counter. The finite state machine then outputs an accurate indication of the state of the device.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to gear shifting systems, methods, and apparatus and more particularly relates to gear shift indicator systems, methods, and apparatus.
[0003] 2. Description of the Related Art
[0004] Engine performance is a pervasive focus of automotive development. One critical aspect of engine performance is optimal gear shifting. Optimal gear shifting includes shifting gears within a range of maximum engine power. Shifting gears within a range of maximum engine power enables the vehicle to maintain an optimal rate of acceleration and avoid overburdening the engine.
[0005] Suboptimal gear shifting is often due to the driver not knowing the precise moment to shift gears. In an attempt to overcome suboptimal gear shifting due to driver error, certain gear shift indicators have been proposed. For example, one proposed gear shift indicator includes a shift indicator designed to turn on once the RPMs reach a selected value. When the driver sees the shift indicator turn on, the driver knows it is time to shift gears.
[0006] However, the foregoing approach works but overlooks a very important factor. For example, the foregoing approach fails to take into account the shift response time between the driver seeing the shift indicator and actually shifting gears. Additionally, the foregoing approach fails to take into account such factors as tire slippage, missed gear transitions, atmospheric conditions, and road conditions.
[0007] From the foregoing discussion, it should be apparent that a need exists for an improved gear shift indication apparatus and method. Beneficially, such an apparatus and method would indicate the optimal gear shift time, taking into account the shift response time of the drive, the current gear, and various driving conditions.
SUMMARY OF THE INVENTION
[0008] The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available imaging means and methods. Accordingly, the present invention has been developed to provide a system, method, and apparatus for indicating a gear shift time that overcome many or all of the above-discussed shortcomings in the art.
[0009] In one aspect of the present invention, an apparatus for communicating an optimal gearshift time includes an input circuit that obtains multiple RPM readings at a selected rate, an acceleration estimation module that determines an RPM acceleration based upon the plurality of RPM readings, a shift time estimation module that determines an appropriate shift time based upon the RPM acceleration and an estimated shift reaction time, and a shift indicator that communicates the appropriate shift time.
[0010] In certain embodiments, the estimated shift reaction time is provide by a reaction time estimator. In one embodiment, the reaction time estimator receives input from a shift point monitor. In one embodiment, the shift point monitor is configured to monitor whether an actual shift occurs in accordance with the appropriate shift time. In such embodiments, the shift point monitor determines a time difference between the appropriate shift time and the actual shift time. The shift point monitor also may communicate the time difference if the time difference is great than a selected time.
[0011] In some embodiments, the appropriate shift time includes shifting within a range of maximum engine power. In certain embodiments, the shift indicator does not communicate the appropriate shift time if the RPM acceleration is greater than a selected value. The shift indicator may include an indicator light or other means of communication such as an audible signal generator, a vibrator or the like.
[0012] In another aspect of the present invention, a method for communicating an optimal gearshift time includes obtaining a plurality of RPM readings at a selected rate, receiving an estimated shift reaction time, determining an RPM acceleration based upon the plurality of RPM readings, determining an appropriate shift time based upon the RPM acceleration and shift reaction time, and communicating the appropriate shift time.
[0013] Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.
[0014] The aforementioned features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:
[0016] FIG. 1 is an engine output graph illustrating the typical power curve of a high-performance engine;
[0017] FIG. 2 is a vehicle speed graph illustrating an expected speed curve under constant engine conditions;
[0018] FIG. 3 a schematic block diagram of one embodiment of a gear shift indicator in accordance with the present invention;
[0019] FIG. 4 is a shift point graph illustrating various shift points in accordance with the present invention; and
[0020] FIG. 5 is a block diagram of one embodiment of a processing module of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Some of the functional units described in this specification have been explicitly labeled as modules, (while others are assumed to be modules) in order to emphasize their embodiment independence. For example, a module may be implemented as a hardware circuit comprising custom VLSI circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.
[0022] Modules may also be implemented in software for execution by various types of processors. An identified module of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module.
[0023] Indeed, a module of executable code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.
[0024] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
[0025] FIG. 1 shows a typical “power curve” of a high-performance engine. This Figure is provided only as a reference for further discussion of the overall operation of the present invention and may vary for different engine types. For example, the peak power for a racing motorcycle engine may occur at 14,000 RPM and a diesel motor may have peak power at 4,000 RPM. Engine manufacturers and professional drivers closely monitor their performance curves as they seek the optimum performance of their engines during development and modification. A dynamometer is one instrument available to measure the power output of their engines under varying conditions.
[0026] Point 1 shows the relatively low power of the subject engine at idle. As fuel is applied the engine RPM increases and the efficiency of the engine improves. At Point 2 the increase in the power output curve is still increasing but the rate of increase begins to reduce due to factors such as friction in the engine, the forces associated with the mass of the pistons as they change direction in the cylinders, the shorter burn time and expansion time as the fuel burns in the cylinders, and the efficiency limitations associated with injecting the fuel and removing the exhaust gasses from the cylinders at higher rotation speeds.
[0027] At Point 3 the power curve begins to decline rapidly due to these same factors identified for Point 2 which can no longer be overcome by adding more fuel. If Point 4 is ever reached the engine is operating well below peak power and further car acceleration is affected. It is in this area that an inexperienced driver may think that their car is performing optimally but, in reality, the experienced driver has shifted to a higher gear ratio and is enjoying more power output in the optimum area of the power curve—which relates directly to improved acceleration—and pulling ahead of the inexperienced driver.
[0028] FIG. 2 shows the expected speed curve assuming constant power is available and no gear shifting is available. The slope of the curve represents the acceleration at any particular point in time. Point 5 shows rapid acceleration. The speed is relatively low and friction from air, bearings, tire rotation, and road conditions is not a significant factor. As Point 6 and Point 7 are reached, wind resistance is becoming much more of a factor. Acceleration is slowed, as represented by the reduction of the slope of the curve at these points.
[0029] Point 8 represents the maximum speed for the power output of the engine. At this point the forward thrust produced by the engine is directly offset by the resistance of the wind and other environmental conditions. The car will not go faster unless the power output of the engine is increased or the aerodynamic shape of the car is improved to reduce air resistance. It should be apparent from FIG. 1 that maximum power is achieved between Point 2 and Point 3 on that curve and an inexperienced driver operating above Point 3 will be at a serious disadvantage in reaching and maintaining maximum speed.
[0030] Present racing tachometers often incorporate a “Shift Light” that may be adjusted to turn on at the upper end of the maximum area of power output as shown at Point 3 in FIG. 1 . When the driver sees this light he or she knows that it is time to shift to a higher gear ratio. This will lower the engine RPM and maintain optimum power output. This approach works but overlooks a very important factor in the overall analysis of the performance of the car and driver. As the car reaches higher and higher speeds the driver continues to shift to a higher gear ratio to maintain optimum power but, as shown in FIG. 2 , the increase in acceleration reduces and therefore it takes significantly longer to reach each succeeding gear shift point.
[0031] In other words, with all variables equal, the change in RPM from the instant the shift indicator is activated until the driver changes gears varies depending on which gear he is currently in. This causes the driver to effectively shift around the optimum shift point. The driver can compensate for this by lowering the shift point RPM setting so that the shift indicator comes on earlier for lower gears. But this approach may cause a situation at higher speeds where the engine acceleration is lower and the shift indicator comes on too soon. The driver will waste an important part of the power curve if this occurs.
[0032] In an attempt to compensate for this problem, some current state-of-the-art racing tachometers incorporate a separate shift point setting for each gear. As each gear ratio is changed the next sequential shift point setting is selected and the indicator light acts accordingly. Patents have been issued for inventions that attempt to overcome these shift-related problems by setting multiple shift points. In theory this works but many factors can interfere with the practical application of this approach. Factors including—tire slippage, missed gear transitions, atmospheric conditions, track conditions for example can all cause the tachometer to misinterpret the shift point. The present invention takes an entirely different approach to these practical problems. Not only does the present invention meet the needs of the drivers and their cars, the present invention does so without incorporating any of the prior inventions.
[0033] FIG. 3 shows a diagram of one embodiment of the present invention. It should be noted that, although FIG. 3 shows the functional modules housed in two physical packages, a tachometer and an enhanced shift indication module 40 , it is possible to combine all, or any combination, of the modules into one housing to produce a tachometer that incorporates the enhanced shift indication module 40 . In certain embodiments, a shift indicator is embodied as an enhanced shift indicator 40 . The enhanced shift indicator 40 may be produced without the RPM display typically associated with a tachometer. Also, the depicted embodiment incorporates a digital stepper motor to move the pointer of the tachometer, and LEDs to light the shift indicator display. It would be equally valid to utilize a digital RPM display, an analog meter movement, a monochrome or color graphical display, and any of a variety of single or multi-color light devices to indicate the optimal shift point or points. In some embodiments sound, vibration, or a form of ‘heads-up’ display device may be used to indicate to the driver when the optimal shift point has been reached.
[0034] A description of each of the modules in FIG. 3 is provided: A car engine 10 has an ignition system 12 which activates each of the engine sparkplugs 14 to ignite the fuel in the associated engine cylinder. The ignition system 12 creates an electrical impulse, which is carried by a wire 16 to the tachometer input circuit 18 . The input circuit 18 processes the impulse to prevent damage to the rest of the tachometer circuitry, to remove extraneous electrical noise prevalent in automobile circuitry, and to combine multiple impulses sometimes utilized to reduce fuel consumption or improve engine efficiency. This input circuit 18 is well known art for an engineer skilled in automotive electronic design.
[0035] The output pulses from the input circuit 18 are fed directly to an input of a processing module 20 . The processing module 20 times each individual pulse and determines the instantaneous engine speed (RPM) each engine cycle. This RPM information is then used to move a stepper motor 22 connected to a pointer 24 that indicates the current motor speed. In other embodiments the processing module 20 could control an analog meter movement or a digital display device to indicate the current RPM of the engine 10 .
[0036] Some tachometers include an internal 26 or remote shift indicator 40 . The processing module 20 , or other circuitry used by the respective tachometer manufacturers, compares the current RPM value with one or more preset values. When the preset level has been reached the shift indicator 26 and/or 40 turns on to indicate that it is time to shift to a higher gear ratio thereby keeping the engine 10 RPM value within the optimum power output curve as shown between point 2 and point 3 in FIG. 1 . In certain embodiments, a reaction time estimator may integrated into the shift point monitor 28 . Alternately, the reaction time estimator may be a sub-module within the processing module 20 or the enhanced shift indication module 40 .
[0037] In various embodiments, the appropriate shift point(s) may be specified by the driver via a reaction time input device (not shown) or extracted by the shift point monitor 28 and saved in the non-volatile memory 30 . In one embodiment, the reaction time input device is integrated into the shift point monitor 28 . In another embodiment, the reaction time input device is integrated into the enhanced shift indication module 40 .
[0038] In certain embodiments, the processing module 20 may be embodied as a microprocessor 20 and associated firmware. In certain embodiments, the processing module 20 provides the current RPM value and additional information to an enhanced shift indication module 40 . In one embodiment, the processing module 20 conveys this information via a serial communications bus 32 .
[0039] The processing module 20 may contain a number of sub-modules such as an acceleration estimation module, a reaction time estimator, and a shift time estimation module (see FIG. 5 ). In one embodiment, the sub-modules comprise software routines. Alternately, the functions of the sub-modules and the shift point monitor 28 may be incorporated into the enhanced shift indication module 40 .
[0040] The enhanced shift indication module 40 could be built into the tachometer or attached to the tachometer as an external module. The enhanced shift indication module 40 may incorporate the pulse wire 16 , the input circuit 18 , the shift point monitor or module 28 , and the nonvolatile memory 30 . Consequently, the present invention could be used in conjunction with a tachometer already installed in a vehicle.
[0041] A shift algorithm incorporated into the present invention may utilize a measured engine RPM 10 to determine the acceleration or deceleration of the engine. This acceleration value may updated at a selected rate used to project the remaining time until the preset shift point will be reached. As the engine RPM approaches the desired shift point this projection is updated until, at the optimum time, taking into account the current acceleration and the pre-set driver's response time, the shift indicator is turned on to indicate to the driver that the next higher gear ratio should be selected.
[0042] The present invention may require an estimated gearshift reaction time for the driver. This may be determined through practice and estimated by the shift point monitor 28 or entered using a separate input device. As the driver becomes more proficient the reaction time may diminish. For example, an inexperienced driver may perform the gear shift operation in ½ of a second while an experienced driver may shift in 1/10 th of a second. If an inexperienced driver has preset his or her shift time too short the engine RPM may overshoot the preset shift point by a significant margin and the present invention may flash the shift indicator rapidly. This feature of the present invention therefore provides feedback in gear shifting skill and facilitates improvement. Alternately, the shift point monitor may adjust the estimated reaction time for the driver.
[0043] Once the present invention knows the optimum shift point for maximum power (Point 3 in FIG. 1 .) and the driver reaction time, the enhanced shift indication module 40 or the processing module 20 utilizes the acceleration value, the current RPM value, and the predetermined optimum shift point setting to turn on the shift indicator at exactly the correct time. External factors such as wind, fuel octane, road conditions, hills and valleys, bearing friction, and atmospheric temperature and pressure may be automatically accommodated by ascertaining the current acceleration. Each of these factors could affect acceleration at any point in time and thus may be incorporated in the calculation of the optimum time to turn on the shift indicator. The result is that the engine 10 is able to spend more time within the optimum power range.
[0044] In one embodiment, a timer triggers the operation of the algorithm greater than 100 times each second. This operation rate may be increased or decreased to meet the needs of faster or slower engines. To simplify discussion of the algorithm two examples of gear ratio shift points numbered points 10 and 12 are shown. A graphical representation of these two shift points is provided in FIG. 4 .
[0045] Shift point 10 . A low gear ratio early in a race: optimum shift point setting is 7,000 RPM; driver shift time is 2/10ths of a second (200 milliseconds), current acceleration near the shift point is 12 (the increase in RPM since the last reading). Shift point 12 . A higher gear ratio later in the race: optimum shift point setting is 7,000 RPM, driver shift time is 2/10ths of a second (200 milliseconds), and the current acceleration near the shift point is 3 (the increase in RPM since the last reading). Note that at shift point 12 the INCREASE in engine RPM is less than at shift point 10 due to many of the factors described earlier in this document.
[0046] The algorithm determines the instantaneous RPM when the time of the current engine cycle is known. This can be determined a number of ways but in one embodiment the engine RPM time is directly converted using a table. The next step is to calculate the difference from the last RPM reading. This difference represents the acceleration at that point in time.
[0047] Since there are slight variances in the RPM readings due to the digital nature of the timing in the processing module 20 the past several readings may be averaged. This may include the past 7 readings, but any appropriate number of past readings could be used or no averaging at all. The result is a number representing the slope of the speed curve with reference to time. If the resulting number is positive the engine is accelerating. If it is negative the engine is slowing down. The magnitude of the number is the acceleration used later in the algorithm.
[0048] The acceleration may be filtered by comparing it to recent readings. If the increase in RPM is VERY rapid it could indicate that the driver is down-shifting and using the engine as a brake. Another possibility is that the wheels are slipping on the road due to lost traction. In either case the acceleration measurements may be filtered and the Shift Indicator may be kept off. The operation of this filter may be changed or eliminated to meet the needs of a particular application without affecting the validity of the present invention.
[0049] In one embodiment, an anticipation value is calculated by multiplying current acceleration value with the Driver Shift Time divided by 10 milliseconds. For example, at shift point ( 10 ) the ‘anticipation’ value is (12*(200/10))=240 RPM. At shift point ( 12 ). the ‘anticipation’ value is (3*(200/10))=60 RPM.
[0050] The ‘anticipation’ value may be subtracted from the Optimum shift point setting preset by the driver. For example, at shift point 10 the shift indicator would turn on at 6,800 RPM and at shift point ( 12 ) the shift indicator would turn on at 6,940 RPM. At both shift points the driver would shift to the higher gear ratio at the indicated time.
[0051] The algorithm presented above is only one possible embodiment of the present invention. Other embodiments may introduce ‘weight’ to each of the three variables used in the calculation (Shift point, Driver delay, and current RPM). For example, the current RPM calculation may give more ‘weight’ or significance to the most recent RPM readings and less to earlier RPM readings. Similar ‘weighting’ may be included with the other variables used in the calculations.
[0052] In short, the present invention provides a significant improvement over prior art. By incorporating the driver's shift reaction time into a shift indicator algorithm and using the results of that calculation to anticipate the time to turn on the shift indicator, the driver will be able to shift more accurately and the engine will operate at it's optimum power position for longer periods during a race. The present invention can be incorporated within a tachometer, attached to an existing tachometer that provides the current RPM readings, or may be used as a stand-alone addition to any vehicle with or without a tachometer.
[0053] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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A method and apparatus for communicating an optimal gear shift time is disclosed. The apparatus includes an input circuit that obtains a plurality RPM readings over a selected interval of time, a processing module that determines an RPM acceleration based upon the plurality of RPM readings, the processing module also determines an appropriate shift time based upon the RPM acceleration and estimated shift reaction time, and a shift indicator that communicates the appropriate shift time. In certain embodiments, the appropriate shift time includes shifting within a range of maximum engine power. In some embodiments, the shift indicator comprises a shift indicator light or an audible signal generator.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a divisional application of and claims priority from related, co-pending, and commonly assigned U.S. patent application Ser. No. 10/685,879 filed on Oct. 15, 2003, entitled “Apparatus and Method for Aerial Rearmament of Aircraft” also by John A. Beyerle and Gary L. Illingworth. Accordingly, U.S. patent application Ser. No. 10/685,879 is herein incorporated by reference.
STATEMENT OF GOVERNMENT INTEREST
[0002] The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment of any royalty thereon.
BACKGROUND OF THE INVENTION
[0003] 1. Technical Field of the Invention
[0004] This invention relates to the field of military aircraft munitions loading, specifically to the provision of a method employing a series of mechanical and electronic components collected and assembled to provide the means for loading munitions onto aircraft while in flight.
[0005] Shrinking defense budgets, combined with the increasing needs of the United States to project its military power often on short notice throughout the world, requires the armed forces to do more with less equipment and fewer personnel. Recently, as can be seen in the case of the war against Iraq, there has been a lack of consensus among allies forcing the United States to “go it alone” when prosecuting the war against terrorism. The nations of Europe, for example, lying closer as they do to areas of turmoil such as the Middle East, are often reluctant to take hard stances against terrorists who lie within an automobile ride from their borders. As can be seen most recently with Turkey during operation “Iraqi Freedom”, nations are often reluctant to promptly provide forward operating locations or to grant flyover rights for United States military aircraft lest these nations seem to be associated too closely with United States military initiatives. The delays caused by these diplomatic barriers can seriously impact United States' combat operational planning.
[0006] What is needed therefore is a method to not only refuel U.S. military aircraft while in flight, so as to extend mission operational effectiveness, but also a means to continually reload the munitions which have been expended during combat operations without having to return to either a distant friendly nation's ground bases, or in the case of naval airpower, to a distant aircraft carrier, to obtain more munitions.
[0007] Military combat aircraft require both fuel and munitions to complete their assigned missions. While the re-fueling of combat aircraft can be accomplished either while on the ground or in the air, the loading of munitions has thus far been limited to the ground. Because of this, the weapons mounts currently found on the pylons of military combat aircraft are designed specifically to be ‘single-shot’ in function and they are re-serviced each time the aircraft lands and takes off. Additionally, aerial rearmament would benefit the extension of airframe serviceable life of combat aircraft which is otherwise degraded each time a combat aircraft's heavy wing loads are stressed during take off. With an aerial re-armament system, combat aircraft would no longer need to take off with any munition as they can all be loaded on the aircraft while in flight. Re-arming the aircraft while in flight would also offer added advantages in terms of military intelligence in that observers (spies) on the ground would not know where a combat aircraft's targets lie in terms of proximity to the ground base, nor what munitions would be employed against a target list. With aerial re-armament, surprise would be achieved and maintained throughout aerial combat operations.
[0008] What is needed therefore is a system for aerial re-armament of combat aircraft so as to enhance the response time, combat effectiveness, deployment options and reach of United States' combat air forces.
OBJECTS AND SUMMARY OF THE INVENTION
[0009] It is therefore an object of the present invention to provide a method for aerial rearmament of combat aircraft.
[0010] One object of the present invention is to provide a method which transfers munitions from a rearming aircraft to the weapons pylons of a combat aircraft while both aircraft are in flight.
[0011] Another object of the present invention is to provide a method to automate the process of guiding the transfer of munitions from a rearming aircraft to the weapons pylons of a combat aircraft.
[0012] Yet another object of the present invention is to provide a method to facilitate the adaptation of any combat aircraft's weapons pylons to munitions transferred from a rearming aircraft in flight.
[0013] Still another object of the present invention is to provide a method for storing in a database all combinations of munitions, rearmament aircraft and combat aircraft types and to configure such combinations in response to an Air Tasking Order (ATO).
[0014] Still yet another object of the present invention is to a method by which the rearming aircraft can alternatively directly release munitions near a target wherein a combat aircraft would provide the guidance for the munition to the target.
[0015] The invention described herein provides a method for rearming combat aircraft in-flight. Said invention comprises a method for the aerial transfer munitions from a rearming aircraft to the weapons pylon of the recipient combat aircraft. Invention further comprises a method for the selection of munitions from a database of munitions and aircraft types in response to an Air Tasking Order. Invention further comprises a method to adapt a variety of combat aircraft to aerial rearmament.
[0016] According to an embodiment of the present invention, method for aerial rearmament of aircraft comprises the steps of extending a boom, where the boom is attachable to and extendible from a rearming aircraft; affixing a munition to the boom; aerodynamically lifting and directionally controlling the boom with the munition affixed; adapting, through a means for adapting, an aircraft which is to be rearmed so as to receive the munition from the boom; and positioning and orienting the munition for transfer from the boom to the adapter of the aircraft to be rearmed and captively engaging the munition onto the aircraft to be rearmed.
[0017] According to another feature of this embodiment of the present invention, method for aerial rearmament of aircraft comprises a first step of first sensing the position of the boom; a second step of sensing the position of the means for adapting; and cooperating between the first step of sensing and the second step of sensing so as to guide the boom to the means for adapting.
[0018] According to yet another feature of this embodiment of the present invention, method for aerial rearmament of aircraft comprises the steps of processing data generated by the first step of sensing and the second step of sensing; generating and forwarding instructions from the step of processing data to a guidance unit; actuating a plurality of control mechanisms so as to effectuate positioning of the boom; capturing an image of the positioning and the orienting of the munition; and displaying the image on a means for viewing by an operator.
[0019] According to still another feature of this embodiment of the present invention, method for aerial rearmament of aircraft comprises the steps of selecting combinations of rearming aircraft, aircraft to be rearmed, and munitions; storing and accessing the selected combinations in a database; determining the quantity, availability, and compatibility of rearming aircraft, aircraft to be rearmed and munitions; and displaying selected combinations.
[0020] According to still yet another feature of this embodiment of the present invention, method for aerial rearmament of aircraft comprises the steps of determining and indicating the azimuth angle, elevation angle and yaw angle of the boom; determining and indicating the distance between the munition on the boom to the adapter on the aircraft to be rearmed; determining and indicating whether or not said munition is “docked”; determining and indicating whether or not the munition is “hooked”; and determining and indicating whether or not the munition is “armed”.
[0021] According to an alternate embodiment of the present invention, method for the direct release of a munition from a rearming aircraft comprises the steps of attaching and extending a boom from the rearming aircraft; conveying, using a conveying means attached to the boom, the munition from the rearming aircraft to end of the boom; providing aerodynamic lift to the boom; and holding, using a holding means attached to the conveying means, the munition to the conveyor, until the holding means is commanded to release the munition.
[0000] Advantages and New Features
[0022] There are several advantages and new features of the present invention relative to the prior art. Important advantages include providing a method for striking strategic targets without regard to forward operating locations or airspace agreements; extending indefinitely the Close Air Support mission in support of forces on the ground; providing a fleet of “virtual” bombers without the cost or time involved in developing more aircraft that are specifically bombers in mission orientation. The invention thus fills the traditional void in airpower theory, that airpower cannot be effective in fighting the unconventional war against insurgents; using the present invention and an aerial task force, as soon as targets ‘pop up’ they can be hit immediately.
[0023] A related advantage stems from the fact that once the present invention has been deployed, the effective airframe life of combat fighter aircraft will be extended because they will not have to takeoff or land with heavy munitions loads on their wings. A new weapons mount designed for multiple loads, or multiple ‘shots’ facilitates such advantage and is part of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 depicts an aerial rearmament system as between a rearming aircraft and an aircraft being rearmed.
[0025] FIG. 2 depicts an aerial rearmament system associated with a rearming aircraft.
[0026] FIG. 3 depicts a block diagram of the components comprising an aerial rearmament system and their interconnections.
[0027] FIG. 4 depicts a munition as it relates to an aircraft weapons pylon of an aerial rearmament system.
[0028] FIG. 5 depicts a computer screen display of an aerial rearmament system operator's interface.
[0029] FIG. 6 depicts a computer screen display showing rearming boom guidance for an aerial rearmament system.
[0030] FIG. 7 depicts both a munition as it relates to an aerial rearming boom, and features of the aerial rearming boom.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] Referring to FIG. 1 , method for aerial rearmament comprises a boom 20 , a first sensor 40 , a Plexiglas faring 50 covering sensor 40 , a weapons platform 60 , a weapons mount 80 and a second sensor 70 located on weapons mount 80 . A rearming aircraft 10 , and a combat aircraft being rearmed 30 are likewise depicted. In this figure, boom 20 is depicted in its extended position. First sensor 40 is located on weapons platform 60 and protected from the slipstream by a transparent Plexiglas fairing 50 . First sensor 40 is guided to second sensor 70 , located on the leading edge of the weapons mount 80 , located on the starboard wing pylon of the combat aircraft 30 . By way of an example munition 90 a General Purpose Mark 82 bomb is shown already loaded onto the port wing of combat aircraft 30 while another is shown in position on weapons mount 80 for placement on the starboard wing.
[0032] Referring to FIG. 2 depicting the perspective from a combat aircraft being rearmed 30 viewing toward rearming aircraft 10 with the boom 20 extended. Control surfaces, or ‘elevons’ 100 located on boom 20 provide both lift and guidance for boom 20 . The weapons platform 60 , and an example munition 90 in this example a General Purpose Mark 82 bomb resting on the weapons platform 60 is being delivered to the combat aircraft's 30 (see FIG. 1 ) weapons mount 80 (see FIG. 1 ).
[0033] Referring to FIG. 3 , an electrical power source 110 from the rearming aircraft 10 provides power for the hydraulic pump 120 , the guidance unit 130 , the computer and monitor 140 , a closed circuit television (CCTV) camera 150 , and sensors 40 located on the weapons platform 60 at the end of the boom 20 .
[0034] Hydraulic power is provided through hydraulic control valves 160 to the boom 20 , and through the boom 20 to the elevons 100 which act as control surfaces to provide lift and maneuverability to the boom 20 when extended into the slipstream behind the rearming aircraft 10 .
[0035] Data in the form of guidance instructions are provided by the computer 140 , to and from the guidance unit 130 , the hydraulic control valves 160 , the elevons 100 , and the weapons platform 60 .
[0036] Data from sensors 40 located on the weapons platform 60 at the end of the boom 20 is transmitted to the computer 140 where it is monitored by the computer guidance software and the human operator. This sensor data is then interpolated into guidance instructions and sent to the guidance unit 130 , continually refreshing the position of the boom 20 and weapons platform 60 in relation to the position of both the combat aircraft 30 and the rearming aircraft 10 . Data on the precise location of the boom 20 and the munition 90 located on the weapons platform 60 is provided by additional sensors 70 located on the weapons mount 80 of the combat aircraft 30 .
[0037] A closed circuit television (CCTV) camera 150 located on the weapons platform 60 at the end of the boom 20 allows the human operator to adjust the camera 150 if necessary to visually monitor the process. Night operations lights 230 , also located on the weapons platform 60 , illuminate the area of activity and allow the human operator to similarly monitor the process visually during darkness.
[0038] Referring to FIG. 4 , boom 20 (see FIGS. 1 and 2 )is telescopically extended outward from the rear of the rearming aircraft 10 (see FIGS. 1 and 2 ). Boom 20 is guided by sensors 40 (see FIG. 1 ) and the computer 140 (see FIG. 3 ) on the rearming aircraft 10 toward the weapons mount 80 located on the pylon of the combat aircraft 30 . Weapons mount 80 is fixed to the pylon by ground crew while the combat aircraft 30 is on the ground through the use of a first pair of standard mounting loops 170 . Once the weapons mount 80 is fixed on the combat aircraft 30 pylon, all other munitions 90 loading can be accomplished while the combat aircraft 30 is airborne.
[0039] A second pair of standard loops 180 are located in tandem on the top surface of the weapon 90 and are forced upward with the motion of the boom 20 until the loops 180 engage the hooks 190 on the weapons mount 80 . Any slight variations in movement necessary to perform this part of the process are facilitated by the articulating pivoting cradle 350 located on the weapons platform 60 . Until the second pair of standard loops 180 on the munition 90 are fully engaged to the hooks 190 on the weapon mount 80 of the combat aircraft 30 , the weapon 90 is held to the weapons platform 60 and the boom 20 through clamping action provided by a set of calipers 200 which open by computer control once electronic and visual verification of attachment is achieved by the human operator.
[0040] During attack runs on the target, the combat aircraft pilot releases the munition 90 in the normal way; when he does this, the repeating gas canister gun 210 fires its round (similar to an eight-gauge shotgun shell) which forces the hooks 190 open and simultaneously forces an assisting plunger 220 downward, pushing the munition 90 away from the weapons mount 80 and towards its target on the ground.
[0041] Referring to FIG. 5 , a computer screenshot is shown which depicts some of the facets of the present invention aerial rearmament system as it might be implemented within a typical Unix-based Command and Control system such as the Theater Battle Management Core System (TBMCS). In this screenshot, all items along the top Tool Bar 240 have their drop down menus visible. In actual operation, each of these drop down menus is collapsed until desired by clicking on it with a mouse or other pointing device. In preparation for the aerial rearmament mission, the human operator selects one item from each of the drop down menus, filling out the online form which then constitutes a database. Each item selected is then inserted into the database file 250 , which is saved with a unique name. This information then becomes part of the Air Tasking Order (ATO) within the TBMCS. When the operator reopens this database file 250 , all the information needed to complete the aerial rearmament mission is available at a glance to the human operator. This database file 250 can either be filled out on the ground before the mission(s), and then either transmitted up to the rearmament aircraft electronically, or loaded into the rearmament aircraft's computer on a floppy disk or other mechanical means, or filled out by the human operator on the rearmament aircraft while in flight and transmitted to the command and control facility located on the ground. Each time a rearmament mission is completed, the remaining available inventory of munitions stores located on the rearmament aircraft is updated in the database and reported to Command and Control personnel on the ground.
[0042] Referring to FIG. 6 , a computer screen shot 260 depicts the computer software indicating guidance progress of the boom 20 (see FIGS. 1 and 2 ) and the munition 90 (see FIGS. 1, 2 and 3 ) to be loaded onto the combat aircraft. The physical location of the first sensor 40 located on the end of the telescoping boom 20 is depicted in relation to its position with respect to the second sensor 70 (see FIGS. 1 and 4 ) located on the front of the weapons mount 80 (see FIGS. 1 and 4 ) which is attached to the appropriate pylon 270 of the combat aircraft 30 (see FIG. 1 ).
[0043] The distance indication 280 (in meters) of the first sensor 40 (i.e., located on the end of the boom 20 ) is calculated by the guidance software. In a like manner, the azimuth 290 (in degrees) of the weapons platform 60 , elevation angle 300 (in degrees), and yaw angle 310 (in degrees) are updated and shown in their respective boxes. When the weapons platform 60 reaches its correct position under the weapons mount 80 it is said to be ‘docked,’ and this condition is then depicted on the display as a green light 320 in the “Docked Yes/No”. Until the docked condition is achieved, a red indicator light 320 remains illuminated.
[0044] The munition 90 only remains in the docked position momentarily, then it is raised slightly to engage its standard loops 180 (see FIG. 4 ) into the two ‘L’ shaped hooks 190 (see FIG. 4 ) located in tandem in the weapons mount. These loops are in standard locations on every munition regardless of type. When the “hooked condition” exists, a green light 330 is illuminated. Prior to this condition a red light 330 is lit.
[0045] The last procedure is the arming state of the munition. An “armed state” is indicated by a green light 340 , which remains illuminated with a red light 340 until armed.
[0046] Referring to FIG. 7 , the present invention is depicted in an additional role directly dropping munitions 90 (such as the Guided Bomb Units (GBUs) shown) from the boom 20 while extended through the rear of a rearming aircraft 10 (see FIGS. 1 and 2 ) such as a C-141, C-130, or C-17 etc. The extended boom 20 , together with elevons 100 , weapons platform 60 , and protective fairing 50 are shown. An endless conveying system 370 is attached underneath the boom 20 , which allows munitions 90 to be conveyed rearward and then released. Once released, the calipers 200 and sway braces 360 which hold the munition 90 to the endless conveying system 370 temporarily until release continue their progress on the conveyor returning to their starting position inside the rearming aircraft 10 in the munitions build area, where another munition 90 can be built and conveyed.
[0047] While the preferred embodiments of the invention have been particularly described in the specification and illustrated in the drawing, it should be understood that the invention is not so limited. Many modifications, equivalents, and adaptations of the invention will become apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
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The invention provides a method for the aerial transfer of munitions from a rearming aircraft to the weapons pylon of the recipient combat aircraft. The invention also provides for the selection of munitions from a database of munitions and aircraft types in response to an Air Tasking Order. The invention allows a variety of combat aircraft to be adapted_to aerial rearmament. The invention also allows the release of precision guided munitions directly from a rearming aircraft so that orbiting combat aircraft can guide these munitions to the target by remote control.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 14/223,361 filed on Mar. 24, 2014, which is a continuation of U.S. patent application Ser. No. 12/684,430 filed on Jan. 8, 2010, now U.S. Pat. No. 8,678,647 issued on Feb. 16, 2010, which is a continuation of U.S. patent application Ser. No. 11/522,794 filed on Sep. 18, 2006, now U.S. Pat. No. 7,661,882 issued on Feb. 16, 2010, which is a continuation of U.S. patent application Ser. No. 10/392,365 filed on Mar. 18, 2003, now U.S. Pat. No. 7,108,421 issued on Sep. 19, 2006, which claims benefit of U.S. Patent Application No. 60/366,062 filed on Mar. 19, 2002. The entire disclosures of each of the above applications are incorporated herein by reference.
FIELD
The present disclosure relates to a system for imaging a subject, and particularly to a system for detecting image radiation.
BACKGROUND
This section provides background information related to the present disclosure which is not necessarily prior art.
In conventional computerized tomography for both medical and industrial applications, an x-ray fan beam and a linear array detector are employed to achieve two-dimensional axial imaging. The quality of these two-dimensional (2D) images is high, although only a single slice of an object can be imaged at a time. To acquire a three-dimensional (3D) data set, a series of 2D images are sequentially obtained in what is known as the “stack of slices” technique. One drawback to this method is that acquiring the 3D data set one slice at a time is an inherently slow process. There are other problems with this conventional tomographic technique, such as motion artifacts arising from the fact that the slices cannot be imaged simultaneously, and excessive exposure to x-ray radiation due to overlap of the x-ray projection areas.
Another technique for 3D computerized tomography is cone-beam x-ray imaging. In a system employing cone-beam geometry, an x-ray source projects a cone-shaped beam of x-ray radiation through the target object and onto a 2D area detector area. The target object is scanned, preferably over a 360-degree range, either by moving the x-ray source and detector in a scanning circle around the stationary object, or by rotating the object while the source and detector remain stationary. In either case, it is the relative movement between the source and object which accomplishes the scanning. Compared to the 2D “stack of slices” approach for 3D imaging, the cone-beam geometry is able to achieve 3D images in a much shorter time, while minimizing exposure to radiation. One example of a cone beam x-ray system for acquiring 3D volumetric image data using a flat panel image receptor is discussed in U.S. Pat. No. 6,041,097 to Roos, et al.
A significant limitation of existing cone-beam reconstruction techniques occurs, however, when the object being imaged is larger than the field-of-view of the detector, which is a quite common situation in both industrial and medical imaging applications. In this situation, some measured projections contain information from both the field of view of interest and from other regions of the object outside the field of view. The resulting image of the field of view of interest is therefore corrupted by data resulting from overlying material.
Several approaches have been proposed for imaging objects larger than the field-of-view of the imaging system. U.S. Pat. No. 5,032,990 to Eberhard et al., for example, discusses a technique for 2D imaging of an object which is so wide that a linear array detector is not wide enough to span the object or part which is to be viewed. The method involves successively scanning the object and acquiring partial data sets at a plurality of relative positions of the object, x-ray source, and detector array. U.S. Pat. No. 5,187,659 to Eberhard et al. discusses a technique for avoiding corrupted data when performing 3D CT on an object larger than the field of view. This technique involves scanning the object with multiple scanning trajectories, using one or more x-ray sources and detectors which rotate in different trajectories relative to the target object. Yet another technique is discussed in U.S. Pat. No. 5,319,693 to Ebarhard et al. This patent discusses simulating a relatively large area detector using a relatively small area detector by either moving the actual area detector relative to the source, or moving the object relative to the area detector. All of these techniques are characterized by complex relative movements between one or more x-ray sources, detectors, and the object being imaged. Furthermore, in each of these techniques, the target object is exposed to excessive x-ray radiation from regions of overlapping projections.
To date, there does not exist a radiation system for imaging large field-of-view objects in a simple and straightforward manner while minimizing the target object's exposure to radiation.
SUMMARY
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
The present invention relates to radiation-based imaging, including 3D computerized tomography (CT) and 2D planar x-ray imaging. In particular this invention relates to methods and systems for minimizing the amount of missing data and, at the same time, avoiding corrupted and resulting artifacts in image reconstruction when a cone-beam configuration is used to image a portion of an object that is larger than the field of view.
An imaging apparatus according to one aspect comprises a source that projects a beam of radiation in a first trajectory; a detector located a distance from the source and positioned to receive the beam of radiation in the first trajectory; an imaging area between the source and the detector, the radiation beam from the source passing through a portion of the imaging area before it is received at the detector; a detector positioner that translates the detector to a second position in a first direction that is substantially normal to the first trajectory; and a beam positioner that alters the trajectory of the radiation beam to direct the beam onto the detector located at the second position. The radiation source can be an x-ray cone-beam source, and the detector can be a two-dimensional flat-panel detector array.
By translating a detector of limited size along a line or arc opposite the radiation source, and obtaining object images at multiple positions along the translation path, an effectively large field-of-view may be achieved. In one embodiment, a detector positioner for translating the detector comprises a positioner frame that supports the detector and defines a translation path, and a motor that drives the detector as it translates within the positioner frame. A positioning feedback system, which can include a linear encoder tape and a read head, can be used to precisely locate and position the detector within the positioner frame. Other position encoder systems could also be used as the positioning feedback system, such as a rotary encoder and a friction wheel.
A radiation source, such as an x-ray source, includes a beam positioning mechanism for changing the trajectory of the emitted radiation beam from a fixed focal spot. This enables the beam to scan across an imaging region, and follow the path of a moving target, such as a translating detector array. In one aspect, the beam positioning mechanism of the present invention enables safer and more efficient dose utilization, as the beam positioner permits the beam to sequentially scan through limited regions of the target object, so that only the region within the field-of-view of the translating detector at any given time need be exposed to harmful radiation.
In one embodiment, a tilting beam positioning mechanism includes a frame which houses the radiation source, and a motorized system connected to both the frame and the source, where the motorized system pivots or tilts the source relative to the frame to alter the trajectory of the radiation beam projected from the source. In a preferred embodiment, the source is pivoted about the focal spot of the projected radiation beam. The motorized tilting system could include, for example, a linear actuator connected at one end to the fixed frame and at the other end to the source, where the length of the actuator controls the angle of tilt of the source, or a motorized pulley system for tilting the source. In another embodiment, a movable collimator is driven by a motor for changing the trajectory of the output beam.
In still another aspect, the invention includes means for rotating the source and translatable detector relative to an object to obtain images at different projection angles over a partial of full 360-degree scan. In one embodiment, the source and detector are housed in a gantry, such as a substantially O-shaped gantry ring, and are rotatable around the inside of the gantry ring. The source and detector can be mounted to a motorized rotor which rotates around the gantry on a rail and bearing system. In another embodiment, the source and translatable detector remain fixed on a support, such as a table, while the object rotates on a turntable or rotatable stage.
The invention also relates to a method of imaging an object comprising projecting a beam of radiation in a first trajectory, the beam traveling through a first region of the object and onto a detector located at a first position; translating the detector to a second position in a direction that is substantially normal to the first trajectory; and altering the trajectory of the beam so that the beam travels through a second region of the object and onto the detector located at the second position. Preferably, the beam of radiation comprises a cone-beam or fan-beam of x-ray radiation, and the detected radiation is used to produce two-dimensional planar or three-dimensional computerized tomographic (CT) object images.
In one aspect, the invention is able to image objects larger than the field-of-view of the detector in a simple and straightforward manner by utilizing a detector positioner that translates the detector array to multiple positions, thus providing an effectively large field-of-view using only a single detector array having a relatively small size. In addition, a beam positioner permits the trajectory of the beam to follow the path of the translating detector, which advantageously enables safer and more efficient dose utilization, as only the region of the target object that is within the field-of-view of the detector at any given time needs to be exposed to harmful radiation.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
FIGS. 1A-C are schematic diagrams showing an x-ray scanning system with a translating detector array according to one embodiment of the invention;
FIGS. 2A-D are side and perspective views illustrating the x-ray source and detector of the system of FIG. 1 ;
FIG. 3 illustrates the wide field-of-view achievable with the translating detector system of the present invention;
FIG. 4 is a schematic diagram showing a data collection matrix of an x-ray scanner system according to one embodiment of the invention;
FIG. 5 is an exploded view of an x-ray detector positioning stage according to one embodiment;
FIGS. 6A-C shows the x-ray detector positioning stage translating to three positions;
FIG. 7 is an exploded view of an x-ray source and source positioning stage according to one embodiment of the invention;
FIG. 8 is a perspective view of an assembled x-ray source and positioning stage;
FIGS. 9A-C shows an x-ray source tilted to three positions by a linear actuator, according to one embodiment of the invention;
FIG. 10 shows a motorized belt and pulley system for tilting an x-ray source to multiple positions, according to another embodiment;
FIG. 11 shows a motorized sliding collimator for directing an x-ray beam to multiple detector positions, according to yet another embodiment;
FIG. 12 is a perspective view of a rotor assembly for rotating an x-ray source and detector within a gantry;
FIG. 13 is a cutaway side view showing the rotor assembly within a gantry ring;
FIG. 14 is a schematic illustration of a mobile cart and gantry assembly for tomographic and planar imaging of large field-of-view objects according to one embodiment;
FIG. 15 illustrates a table-top x-ray assembly with rotatable stage for tomographic and planar imaging of large field-of-view objects according to yet another embodiment; and
FIG. 16 shows a detector that is translated along a line.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION
Example embodiments will now be described more fully with reference to the accompanying drawings.
FIGS. 1A-C schematically illustrate an x-ray scanning system with a translating detector array according to one embodiment of the invention. The scanning system shown in FIGS. 1A-C includes gantry 11 , which in this embodiment comprises a generally circular, or “O-shaped,” housing having a central opening into which an object being imaged is placed. The gantry 11 contains an x-ray source 13 (such as a rotating anode pulsed x-ray source) that projects a beam of x-ray radiation 15 into the central opening of the gantry, through the object being imaged, and onto a detector array 14 (such as a flat panel digital detector array) located on the opposite side of the gantry. The x-rays received at the detector 14 can then be used to produce a 2D planar or 3D tomographic object reconstruction images using well-known techniques.
The detector 14 is translated to multiple positions along a line or arc in a direction that is generally normal to the trajectory of beam 15 . This permits the detector to capture images of objects that are wider than the field-of-view of the detector array. FIGS. 1A-1C show the large field-of-view imaging area when the detector is translated to three positions along an arc opposite the x-ray source. This is more clearly illustrated in FIGS. 2A-C , which are side views of the source and detector as the detector translates to three different positions. FIG. 2D is a perspective view showing the resultant large imaging field-of-view by combining the data obtained at all three source and detector positions. As shown in FIGS. 2A-C , as the detector moves to each subsequent position, the last column of detector pixels 41 is positioned adjacent to the location of the leading column of pixels 42 from the prior detector position, thereby providing a large “effective” detector having a wide field-of-view, as shown in FIG. 2D . The image obtained is a combination of the three images abutted against one another, resulting in a large field-of-view using only a single detector array having a relatively small size. The detector 14 being translated along a line is illustrated in FIG. 16 .
The source 13 preferably includes a beam positioning mechanism for changing the trajectory of the beam 15 from a stationary focal spot 40 , so that the beam follows the detector as the detector translates, as shown in FIGS. 1A-C . This permits safer and more efficient dose utilization, as generally only the region of the target object that is within the field-of-view of the detector at any given time will be exposed to potentially harmful radiation.
Preferably, the translational movement of the detector and the trajectory of the x-ray beam can be automatically coordinated and controlled by a computerized motor control system.
FIG. 3 illustrates the large field-of-view obtainable using the translating detector array of the present invention, as compared to the field-of-view of the same array in a conventional static configuration. The small and large circles represent varying diameters of the region centered on the axis of the imaging area that is within the field-of-view of the detector for the non-translatable and translatable arrays, respectively. The diameter of this imaging region is approximately half the width of the detector, since the beam diverges in the shape of a cone as it projects from the focal spot of the source onto the detector array. As shown in FIG. 3 , the diameter of this imaging region can be greatly increased by translating the detector array and scanning the x-ray beam to multiple positions along a line or arc on the gantry.
In one aspect, the x-ray source 13 and translatable detector 14 are rotatable around the interior of the gantry, preferably on a motorized rotor, to obtain large field-of-view x-ray images from multiple projection angles over a partial or full 360-degree rotation. Collection of multiple projections throughout a full 360-degree rotation results in sufficient data for three-dimensional cone-beam tomographic reconstruction of the target object.
As shown in the matrix diagram of FIG. 4 , there are at least two methods for obtaining large field-of-view images over a partial or full 360-degree rotational scan of the target object. In the first method, for each rotational angle of the source and detector within the gantry, the detector is translated to two or more positions, capturing x-ray images at each detector position. This is shown in the top row of the matrix diagram of FIG. 4 , where the x-ray source and detector stage are maintained at Rotor Angle 0 , while the detector translates on the stage to Detector Positions 1 - 3 . The rotor carrying the x-ray source and detector stage then rotate to a second position on the gantry, Rotor Angle 1 , and the detector again translates to the three detector positions. This process repeats as the x-ray source and detector stage rotate through N rotor positions on the gantry to obtain large field-of-view object images over a full 360-degree scan.
In a second method, for each position of the translating detector, the source and detector stage perform a partial of full 360-degree rotation around the target object. This is shown in the leftmost column of the matrix diagram of FIG. 4 , where detector is maintained at Detector Position 1 , while the source and detector stage rotate within the gantry to Rotor Angles 0 through N. Then, as shown in the center column of FIG. 4 , the detector is translated to Detector Position 2 , and the source and detector stage are again rotated to Rotor Angles 0 through N. This process is repeated for each position of the translating detector array, with the source and detector stage performing a partial or full scan around the target object for each detector position.
Turning now to FIG. 5 , an x-ray detector positioner 100 according to one embodiment of the invention is shown in exploded form. The positioning stage comprises a detector carriage 101 for holding the detector, a friction drive 102 which attaches to the detector carriage, and a positioner frame 103 upon which the detector carriage is movably mounted, The positioner frame includes two parallel side walls 104 , a base 105 , and a series of lateral frames 106 extending between the side walls. The interior of the side walls 104 include three main concentric surfaces extending the length of the frame. On top of each side wall 104 is a flat surface upon which a friction wheel 109 is driven, in the center is a v-groove rail on which a pair of v-groove rollers 110 ride, and on the bottom is another flat surface upon which a linear encoder tape is affixed.
In the embodiment shown, the concentric radii of the components of the curved side rails vary as a function of a circumscribed circle centered at the focal spot of an x-ray source. The central ray or line that connects the focal spot to the center pixel of the detector array is essentially perpendicular to the flat face of the detector array. By moving the translating detector components along the defined curved side rails, the face of the detector translates tangentially to the circle circumscribed by connecting the ray or line that connects the focal spot to the center pixel of the detector array. Other embodiments include a circle with infinite radius, in which case the curved side rails become straightened along a flat plane or line.
The friction drive 102 consists of a servomotor, gear head, belt drive, axle, and friction wheels 109 . The friction drive is mounted to the detector carriage 101 by brackets 107 . The friction wheels 109 are preferably spring-loaded and biased against the flat top surface of the side walls 104 . The rollers 110 are mounted to brackets 107 , and pressed into the central v-grooves of the positioner side walls 104 . The v-groove rollers 110 precisely locate the detector carriage 101 as well as allow loading from any direction, thus enabling the accurate positioning of the translated detector array independent of gantry angle or position. The friction wheel 109 minimizes the backlash in the positioning system. In addition, a read head 108 is located on a detector carriage bracket 107 for reading the encoder tape affixed to the bottom flat surface of the positioner side wall 104 . The read head 108 provides position feedback information to the servomotor for precise positioning of the detector carriage along the concentric axis of travel. The x-ray detector positioner 100 can also include bearings 29 attached to side walls 104 for rotating the entire detector assembly around the interior of a gantry, as described in further detail below.
Referring to FIGS. 6A-C , the assembled detector positioner 100 is shown translating the detector carriage 101 to multiple positions along an arc. In operation, the detector carriage 101 and friction drive assembly 102 are precisely moved by the servomotor along the concentric axis of the positioning frame and accurately positioned by the linear encoder system. Three positions are shown in FIGS. 6A-C , although the detector carriage 101 may be precisely positioned at any point along the arc defined by the positioner frame 103 . The compact nature of the friction drive 102 allows for maximum translation of the detector carriage 101 while the drive 102 remains completely enclosed within the positioner frame 103 , and allows the distal ends of the detector carriage to extend beyond the edge of the positioner frame (as shown in FIGS. 6A and 6C ) to further increase the “effective” field-of-view obtainable with the detector.
As discussed above, the imaging system of the present invention preferably includes a radiation source with a beam positioning mechanism for changing the trajectory of the radiation emitted from a fixed focal spot, so that the beam may scan across multiple positions. One embodiment of an x-ray source stage 200 with a beam positioning mechanism is shown in FIG. 7 . The stage comprises an outer wall frame 201 (shown in exploded form) which encloses the x-ray source 13 , a swiveling x-ray source mount 202 , and a servomotor linear actuator 203 . The x-ray source is supported on the bottom by source mount 202 and from the sides by a pair of bushing mounts 206 . The bushing mounts 206 are connected to the outer wall frame 201 by precision dowel pins 204 that are press-fit into bushings 205 . The dowel pins 204 permit the bushing mounts 206 , and thus the x-ray source 13 and source mount 202 , to pivot with respect to the outer wall frame 201 pivoting motion. This pivoting motion is preferably centered at the focal spot of the x-ray source.
The precision servomotor linear actuator 203 is attached at one end to the outer wall frame 201 , and at the other end to the swiveling x-ray source mount 202 . By varying the length of the motorized linear actuator 203 , the source mount 202 and x-ray source 13 can be pivoted about dowel pins 204 to tilt the x-ray source about its focal spot in a controlled manner. The fully assembled x-ray source stage is shown in FIG. 8 .
The operation of the x-ray source and tilting beam positioning mechanism is shown in FIGS. 9A-9C . As the linear actuator moves from a fully retracted position ( FIG. 9A ) to a fully extended position ( FIG. 9C ) the x-ray source pivots about its focal spot, thus altering the trajectory of the emitted radiation beam. In this embodiment, the pivot point represents the center of a circle with a radius defined by the distance from the focal spot to the center pixel of the detector array. The pivot angle is computed by determining the angle defined by the line connecting the focal spot of the x-ray detector and the center pixel of the detector array. A computerized motion control system can be used to synchronize the x-ray source tilt angle with the position of a translating detector array so that the x-ray beam remains centered on the detector even as the detector translates to different positions.
Various other embodiments of an x-ray beam positioner can be employed according to the invention. For example, as shown in FIG. 10 , the x-ray source can be tilted to multiple positions by a motorized belt and pulley system. In another embodiment shown in FIG. 11 , the trajectory of the x-ray beam is altered by a sliding collimator that is driven by a servomotor.
As shown in FIG. 12 , the x-ray source stage 200 and x-ray detector positioner 100 can be joined together by a curved bracket assembly 301 to produce a C-shaped motorized rotor assembly 33 . The rigid bracket 301 maintains the source and detector opposed to one another, and the entire rotor assembly can be rotated inside an O-shaped x-ray gantry. The rotor assembly 33 can also include a motor 31 and drive wheel 32 attached at one end of the rotor for driving the rotor assembly around the interior of the gantry.
FIG. 13 is a cutaway side view of a gantry 11 which contains a C-shaped motorized rotor 33 . The interior side walls of the gantry include curved rails 27 extending in a continuous loop around the interior of the gantry. The drive wheel 32 of the rotor assembly 33 contacts the curved rail 27 of the gantry, and uses the rail to drive the rotor assembly around the interior of the gantry. A rotary incremental encoder can be used to precisely measure the angular position of the rotor assembly within the gantry. The incremental encoder can be driven by a friction wheel that rolls on a concentric rail located within the sidewall of the gantry. The rotor assembly 33 also includes bearings 29 , which mate with the curved rails 27 of the gantry to help guide the rotor assembly 33 as it rotates inside the gantry. The interior of the gantry ring 11 can include a slip ring that maintains electrical contact with the rotor assembly 33 to provide the power needed to operate the x-ray source, detector, detector positioner, and/or beam positioner, and also to rotate the entire assembly within the gantry frame. The slip ring can furthermore be used to transmit control signals to the rotor, and x-ray imaging data from the detector to a separate processing unit located outside the gantry. Any or all of the functions of the slip ring could be performed by other means, such as a flexible cable harness attached to the rotor, for example.
Although the rotor assembly of the preferred embodiment is a C-shaped rotor, it will be understood that other rotor configurations, such as O-shaped rotors, could also be employed. For example, a second curved bracket 301 could be attached to close the open end of the rotor, and provide a generally O-shaped rotor. In addition, the x-ray source and detector could rotate independently of one another using separate mechanized systems.
An x-ray scanning system 10 according to one aspect of the invention generally includes a gantry 11 secured to a support structure, which could be a mobile or stationary cart, a patient table, a wall, a floor, or a ceiling. As shown in FIG. 14 , the gantry 11 is secured to a mobile cart 12 in a cantilevered fashion via a ring positioning unit 20 . In certain embodiments, the ring positioning unit 20 enables the gantry 11 to translate and/or rotate with respect to the support structure, including, for example, translational movement along at least one of the x-, y-, and z-axes, and/or rotation around at least one of the x- and y-axes. X-ray scanning devices with a cantilevered, multiple-degree-of-freedom movable gantry are described in commonly owned U.S. Provisional Applications 60/388,063, filed Jun. 11, 2002, and 60/405,098, filed Aug. 21, 2002, the entire teachings of which are incorporated herein by reference.
The mobile cart 12 of FIG. 14 can optionally include a power supply, an x-ray power generator, and a computer system for controlling operation of the x-ray scanning device, including translational movement of the detector, and tilting movement of the x-ray source. The computer system can also perform various data processing functions, such as image processing, and storage of x-ray images. The mobile cart 12 preferably also includes a display system 60 , such as a flat panel display, for displaying images obtained by the x-ray scanner. The display can also include a user interface function, such as a touch-screen controller, that enables a user to interact with and control the functions of the scanning system. In certain embodiments, a user-controlled pendant or foot pedal can control the functions of the scanning system. It will be understood that one or more fixed units can also perform any of the functions of the mobile cart 12 .
The O-shaped gantry can include a segment that at least partially detaches from the gantry ring to provide an opening or “break” in the gantry ring through which the object to be imaged may enter and exit the central imaging area of the gantry ring in a radial direction. An advantage of this type of device is the ability to manipulate the x-ray gantry around the target object, such as a patient, and then close the gantry around the object, causing minimal disruption to the object, in order to perform x-ray imaging. Examples of “breakable” gantry devices for x-ray imaging are described in commonly-owned U.S. patent application Ser. No. 10/319,407, filed Dec. 12, 2002, now U.S. Pat. No. 6,940,941, issued Sep. 6, 2005, the entire teachings of which are incorporated herein by reference.
It will also be understood that although the embodiments shown here include x-ray imaging devices having O-shaped gantries, other gantry configurations could be employed, including broken ring shaped gantries having less than full 360 degree rotational capability.
Referring to FIG. 15 , a table-top version of the large field-of-view scanning device is depicted. In this embodiment, the connector bracket, gantry, and rotor friction drive have been replaced by a rigid table mount 302 and a turntable 303 located in the center of the field of view. The turntable rotates the object to be imaged in a complete 360-degree rotation to capture projection images from any direction. The detector and source positioning assemblies 100 , 200 are rigidly mounted a fixed distance from one another. The turntable 303 can be rigidly mounted to the table at any point along the ray connecting the x-ray focal spot and the center of the detector positioning assembly. The data collection techniques for this embodiment are essentially the same as those described for the x-ray gantry, except that in this case, it is the rotation of the object relative to the source and detector, rather than the rotation of the source and detector relative to the object, which effects the x-ray scanning.
The x-ray imaging systems and methods described herein may be advantageously used for two-dimensional and/or three-dimensional x-ray scanning. Individual two-dimensional projections from set angles along the gantry rotation can be viewed, or multiple projections collected throughout a partial or full rotation may be reconstructed using cone or fan beam tomographic reconstruction techniques. This invention could be used for acquiring multi-planar x-ray images in a quasi-simultaneous manner, such as described in commonly-owned U.S. patent application No. 10/389,268 entitled “Systems and Methods for Quasi-Simultaneous Multi-Planar X-Ray Imaging,” , filed on Mar. 13, 2003, now U.S. Pat. No. 7,188,998, issued on Mar. 13, 2007, the entire teachings of which are incorporated herein by reference. Also, the images acquired at each detector position could be reprojected onto virtual equilinear or equiangular detector arrays prior to performing standard filtered backprojection tomographic reconstruction techniques, as described in commonly-owned U.S. Provisional Application No. 60/405,096, filed on Aug. 21, 2002.
The detector arrays described herein include two-dimensional flat panel solid-state detector arrays. It will be understood, however, that various detectors and detector arrays can be used in this invention, including any detector configurations used in typical diagnostic fan-beam or cone-beam imaging systems, such as C-arm fluoroscopes. A preferred detector is a two-dimensional thin-film transistor x-ray detector using scintillator amorphous-silicon technology.
While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. For instance, although the particular embodiments shown and described herein relate in general to computed tomography (CT) x-ray imaging applications, it will further be understood that the principles of the present invention may also be extended to other medical and non-medical imaging applications, including, for example, magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), ultrasound imaging, and photographic imaging.
Also, while the embodiments shown and described here relate in general to medical imaging, it will be understood that the invention may be used for numerous other applications, including industrial applications, such as testing and analysis of materials, inspection of containers, and imaging of large objects.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
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An imaging apparatus and related method comprising a detector located a distance from a source and positioned to receive a beam of radiation in a trajectory; a detector positioner that translates the detector to an alternate position in a direction that is substantially normal to the trajectory; and a beam positioner that alters the trajectory of the radiation beam to direct the beam onto the detector located at the alternate position.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a damper comprising a flexible guiding damping unit in particular for spin-drying washing machines.
[0003] 2. Background Art
[0004] Dampers of the generic type are known for example from DE 196 15 010 A1. Owing to low-cost manufacture, there is undesired play between the tappet and casing in those dampers. Upon operation of a washing machine that comprises those dampers, undesired noise develops by the tappet hitting against the casing. Moreover, the lifetime of those dampers is reduced as a result of increased wear between the tappet and the casing.
SUMMARY OF THE INVENTION
[0005] It is an object of the invention to develop a damper of the type mentioned at the outset in such a way that low-noise and low-wear guidance of the tappet in the casing is ensured, accompanied with manufacture at a low cost.
[0006] This object is attained by the features including a substantially tubular casing which has a central longitudinal axis and an end on the side of a tappet and a free end; a tappet which is displaceably guided in the casing and projects from the end on the side of the tappet, having a central longitudinal axis and an end inside the casing and a free end; fastening elements which are mounted on the free end of the casing and on the free end of the tappet; a frictional damping unit for producing a given frictional damping effect between the casing and the tappet; and a guiding damping unit for damping and centering any deflection of the tappet crosswise of the central longitudinal axis of the casing. The gist of the invention resides in providing the damper with a guiding damping unit that will attenuate any radial deflections of the damper and center the tappet in the casing.
[0007] Additional features and advantages of the invention will become apparent from the ensuing description of five exemplary embodiments of the invention, taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0008] FIG. 1 is a diagrammatic elevation of a first embodiment of a cylinder washing machine with dampers;
[0009] FIG. 2 is a longitudinal sectional view of a damper of FIG. 1 ;
[0010] FIG. 3 is a perspective illustration of a guiding damping unit of the damper of FIG. 2 ;
[0011] FIG. 4 is a plan view of the guiding damping unit of FIG. 3 ;
[0012] FIG. 5 is a longitudinal sectional view of a second embodiment of a damper;
[0013] FIG. 6 is a perspective view of a guiding damping unit of the damper of FIG. 5 ;
[0014] FIG. 7 is a plan view of the guiding damping unit of FIG. 6 ;
[0015] FIG. 8 is a plan view of a third embodiment of a guiding damping unit;
[0016] FIG. 9 is a perspective view of the guiding damping unit of FIG. 8 ;
[0017] FIG. 10 is a plan view of a fourth embodiment of a guiding damping unit;
[0018] FIG. 11 is a perspective view of the guiding damping unit of FIG. 10 ;
[0019] FIG. 12 is a perspective view of a fifth embodiment of a guiding damping unit; and
[0020] FIG. 13 is a plan view of the guiding damping unit of FIG. 12 .
DESCRIPTION OF PREFERRED EMBODIMENTS
[0021] The following is a detailed description of a damper comprising a guiding damping unit according to a first embodiment, taken in conjunction with FIGS. 1 to 4 . A cylinder washing machine comprises a vibratory washing aggregate 2 with a driving motor 3 which actuates a washing cylinder (not shown in detail) via a belt drive 4 . By way of two dampers 5 , which are going to be described in detail, the vibratory washing aggregate 2 supports itself on a basic machine frame 6 on the ground. Additionally, the washing aggregate 2 is vibratorily suspended on the machine frame 6 by means of helical extension springs 7 . Consequently, the washing aggregate 2 combines with the dampers 5 and the helical extension springs 7 , constituting a spring-damper system vibratorily lodged in the machine frame 6 for damping any imbalances during spin-drying jobs of the washing cylinder.
[0022] Each damper 5 comprises a substantially tubular casing 8 with a central longitudinal axis 9 . Tubular casings are understood to be casings of round as well as noncircular, in particular rectangular cross-sectional shape. The free end 10 of the tubular casing 8 is closed by a bottom 11 . A first fastening element 12 is fixed to the outside of the bottom 11 , including a first bearing 13 and a bearing bush 14 which is fixed inside the bearing 13 . By means of the first fastening element 12 , the damper 5 is mounted on the machine frame 6 for pivotability in relation to the washing aggregate 2 about a pivoting axis 15 which is parallel to the cylinder axis of rotation 16 .
[0023] The damper 5 further comprises a tappet 17 which possesses a central longitudinal axis 18 and, on its free end 19 , a second fastening element 20 with a second bearing 21 . The second fastening element 20 is inserted into the free end 19 of the tubular tappet 17 , where it is fixed by positive fit so that the second fastening element 20 closes the free end 19 . By way of the second fastening element 20 , the damper 5 is mounted on the washing aggregate 2 in such a way that the damper 5 is rotatable about a second pivoting axis 22 which is also parallel to the cylinder axis of rotation 16 .
[0024] By its end 23 , inside the casing 8 , the tappet 17 is inserted into the end 24 of the casing 8 on the side of the tappet 17 . Upon ideal guidance of the tappet 17 inside the casing 8 , the central longitudinal axis 9 of the casing 8 and the central longitudinal axis 18 of the tappet 17 coincide. In the direction of the central longitudinal axes 9 , 18 , the motion of the tappet 17 , which is displaceably mounted in the casing 8 , is damped by a frictional damping unit 26 . The frictional damping unit 26 is disposed inside a casing cup 27 . The casing cup 27 has a bottom 28 which is pierced by the end 24 of the casing 8 on the side of the tappet 17 , the cup 27 and the casing 8 being one piece. The end 24 on the side of the tappet 17 extends as far as approximately to the middle of the casing cup 27 .
[0025] The frictional damping unit 26 comprises an annular frictional damping lining 29 , a contact-pressure-piston component 30 , a fastening-piston component 31 and a first spring 32 as well as a second spring 33 . The annular frictional damping lining 29 rests on the outside wall of the tappet 17 ; it is pressed against the outside wall of the tappet 17 by the contact-pressure-piston component 30 and held in the direction of the free end 19 of the tappet 17 . In the direction of the end 23 , inside the casing 8 , of the tappet 17 , the frictional damping lining 29 is held by the fastening-piston component 31 . In the direction of the central longitudinal axes 9 , 18 , the end of the fastening-piston component 31 that is turned towards the inside wall of the casing cup 27 comprises an annular locking projection 34 which combines with the end of the contact-pressure-piston component 30 that is turned towards the end 23 , inside the casing 8 , of the tappet 17 , forming a rear recess of positive fit and fixing the fastening-piston component 31 and the contact-pressure-piston component 30 . The first spring 32 is pre-loaded between a stop 35 of the fastening-piston component 31 and an annular stop 36 on the inside wall of the casing cup 27 in vicinity to the bottom 28 thereof. By contrast, the second spring 33 is pre-loaded between a stop 37 of the contact-pressure-piston component 30 and a stop 38 of a cap 39 .
[0026] The cap 39 is cup-shaped too, on its bottom 40 having a guiding damping unit 41 which the free end 19 of the tappet 17 passes through and which serves for damping any deflection of the tappet 17 crosswise of the central longitudinal axis 9 of the casing 8 and for centering the tappet 17 . The cap 39 has a greater diameter than the cup 27 ; it is pushed over the cup 27 in the direction of tappet insertion 42 and fixed thereto. Fixing takes place by means of locking noses 43 which combine with the outer wall of the cup 27 , forming rear recesses.
[0027] The following is a detailed description of the cap 39 and the guiding damping unit 41 . The cap 39 comprises a basic cap structure 44 which tapers in the direction of the bottom 40 of the cap 39 , having ventilation apertures 45 uniformly distributed along the circumference. The guiding damping unit 41 is disposed inside the bottom 40 , having a tappet inlet 46 ; the unit 41 and the basic cap structure 44 are integral. From the non-tapered end of the basic cap structure 44 , fastening ribs 48 extend in the direction of a central longitudinal axis 47 of the cap 39 which is identical with the central longitudinal axis 9 of the casing 8 ; they are regularly distributed along the circumference and, by their free ends, joined to a fastening ring 49 , possessing the locking noses 43 on their inside wall in proximity to their free ends.
[0028] The guiding damping unit 41 is comprised of several annularly disposed damping elements 50 which are formed in one piece with the cap 39 . The unit 41 is integrally injection-molded from plastic material, in particular POM or polyamide. The damping elements 50 are regularly distributed along the circumference, related to the central longitudinal axis 47 of the cap 39 , two of the damping elements 50 at a time facing each other diametrically as related to the central longitudinal axis 47 of the cap 39 . Each damping element 50 has a U-shaped profile with an inner rib portion 51 and an outer rib portion 52 which is longer than the inner rib portion 51 , the outer rib portion 52 being curved in accordance with an outside radius and the inner rib portion 51 being curved in accordance with an inside radius as related to the central longitudinal axis 47 of the cap 39 and the outside radius being greater than the inside radius. The inner rib portion 51 and the outer rib portion 52 are interconnected by a curved connecting rib portion 53 and jointly enclose a chamber 66 which is open only in the axial direction. The outer rib portion 52 additionally possesses a radially inward stop 55 in the shape of a wedge which defines the mobility of the inner rib portion 51 radially outwards. It is also possible to define the radial motion of the rib portions without a stop. To this end, the stability and geometry of the rib portions must be selected suitably. The guiding damping unit 41 is rotationally symmetrical of the central longitudinal axis 47 of the cap 39 by an angle of 360° divided by the number of damping elements 50 . The spring characteristic of the damping elements 50 is adjustable by way of their geometry. Owing to the one-piece design of the damping elements 50 , the inner rib portions 51 thereof form a closed inner ring 67 and the outer rib portions 52 an outer ring, both rings being interconnected by the connecting rib portions 53 . The tappet 17 slides on the ring 67 by some play.
[0029] The following is a detailed description of the mode of operation of the damper 5 with the guiding damping unit 41 . Upon operation of the cylinder washing machine 1 , loads act on the damper 5 as a result of imbalances of the washing cylinder of the washing aggregate 2 in the direction of its central longitudinal axes 9 , 18 , 47 and crosswise thereof. The ensuing description proceeds from a sudden rise in the stimulation of load on the tappet 17 in the direction of tappet insertion 42 . A first case of stimulation of load on the tappet 17 precisely in the direction of the central longitudinal axis 9 of the casing 8 is differentiated from another case in which stimulation does not take place precisely in the direction of the central longitudinal axis 9 i.e., there is a transverse-load component.
[0030] Proceeding from the position of rest of the damper 5 seen in FIG. 2 , the tappet 17 moves precisely in the direction of the central longitudinal axis 9 of the casing 8 in the direction of tappet insertion 42 in the first case of actuation of the tappet 17 by load. Upon insertion, the central longitudinal axis 18 of the tappet 17 is identical with the central longitudinal axis 9 of the casing 8 , there being no transverse-load component. As a result of the friction between the frictional damping lining 29 and the outside wall of the tappet 17 , the frictional damping lining 29 , together with the contact-pressure-piston component 30 and the fastening-piston component 31 , is being entrained by the motion of insertion of the tappet 17 in the direction of tappet insertion 42 . During this motion of insertion, the fastening-piston component 31 slips over the end 24 of the casing 8 on the side of the tappet 17 , loading the first spring 32 . If the spring load of the increasingly loaded first spring 32 exceeds the frictional force that acts between the frictional damping lining 29 and the tappet 17 , the result is reversion of the motion of the frictional damping lining 29 and the contact-pressure-piston component 30 and the fastening-piston component 31 so that the first spring 32 relaxes partially. The frictional damping lining 29 now moves counter to the direction of tappet insertion 42 and, as a result of the frictional force, brakes the motion of the tappet 17 in the direction of tappet insertion 42 until there is a reversion of motion of the tappet 17 . As the motion of the tappet 17 and of the frictional damping lining 29 proceeds counter to the direction of tappet insertion 42 , the first spring 32 relaxes more and more, whereas the second spring 33 is being loaded increasingly. If the spring load of the second spring 33 exceeds the frictional force that acts between the frictional damping lining 29 and the tappet 17 , there will be a renewed reversion of the motion of the frictional damping lining 29 together with the contact-pressure-piston component 30 and the fastening-piston component 31 , with the second spring 33 again relaxing. As a result of the frictional force that acts between the frictional damping lining 29 and the tappet 17 , the motion of the tappet 17 counter to the direction of tappet insertion 42 is again being braked until there is also a reversion of motion of the tappet 17 .
[0031] That motional process is repeated several times. Consequently, the tappet 17 performs damped vibration within the casing 8 . Upon stimulation of load precisely in the direction of the central longitudinal axis 9 of the casing 8 , the guiding damping unit 41 only has the function of additional guidance of the tappet 17 . The damping elements 50 are not active in that case.
[0032] As regards the second case of load stimulation not precisely in the direction of the central longitudinal axis 9 of the casing 8 , the stimulation of load can be divided into a component in the direction of the central longitudinal axis 9 of the casing 8 and into another component crosswise of the central longitudinal axis 9 . As for the load component in the direction of the central longitudinal axis 9 of the casing 8 , the mode of operation of the damper 5 is the same as described in the first case. The load component crosswise of the central longitudinal axis 9 of the casing 8 leads to deflection of the free end 19 of the tappet 18 crosswise of the central longitudinal axis 9 of the casing 8 , the central longitudinal axis 18 of the tappet 17 no longer coinciding with the central longitudinal axis 9 of the casing 8 . The deflection of the tappet 17 crosswise of the central longitudinal axis 9 of the casing 8 is damped by the guiding damping unit 41 so that centering of the tappet 17 takes place in such a way that the central longitudinal axis 18 of the tappet 17 again coincides with the central longitudinal axis 9 of the casing 8 .
[0033] The ensuing description of the mode of operation of the guiding damping unit 41 proceeds from the assumption that the transverse-load component works on a plane that intersects the central longitudinal axis 47 of the cap 39 and two opposed stops 55 of two diametrically opposed damping elements 50 . As a result of the transverse load component, the inner rib portion 51 of the damping element 50 moves radially outwards. In doing so, the connecting-rib portion 53 is loaded such that spring load originates in the direction of the central longitudinal axis 47 of the cap 39 . This spring load brakes any radial deflection of the tappet 17 and leads to a reversion of motion of the tappet 17 in the direction of the central longitudinal axis 47 of the cap 39 . In the moving process specified, the inner rib portion 51 of the diametrically opposed damping element 50 is first being moved in the direction of the central longitudinal axis 47 of the cap 39 , with the connecting-rib portion 53 also building up spring load, however of radially outward action. This also results in that the motion of the tappet 17 in the transverse direction is being braked and damped. The friction losses that are responsible for the damping effect primarily originate in the material structure of the damping elements 50 as a result of lossy flexible deformation. What imports is the reduction of energy of motions in the radial direction. Consequently, the guiding damping unit 41 serves for damping any deflection of the tappet 17 crosswise of the central longitudinal axis 9 of the casing 8 and for simultaneously centering the tappet 17 after disappearance of the transverse-load component. In case of transverse-load components of great amplitude, any deflection of the tappet 17 is defined by the wedge-shaped, projecting stops 55 . Consequently, the damper 5 and the guiding damping unit 41 lead to clearly reduced noises of the damper 5 during operation of the cylinder washing machine 1 and to clearly reduced wear of the damper 5 as a result of the tappet 17 being permanently centered.
[0034] The following is a description of a second embodiment of the invention, taken in conjunction with FIGS. 5 to 7 . Parts of identical construction have the same reference numerals as in the first embodiment, to the description of which reference is made. Parts that differ in construction, but are functionally identical, have the same reference numerals with an a annexed. The decisive difference from the first embodiment resides in that the frictional damping coating 29 a passes by friction along the inside wall of the casing 8 a. To this end, the tappet 17 a is of two-piece design, with the first tappet component 56 being integral with the second fastening element 20 a and a blind hole 57 that is concentric of the central longitudinal axis 18 of the tappet 17 a varying in diameter for connection to a second tappet component 58 by positive fit and frictional engagement. The precise design of the blind hole 57 is not going to be explained in detail. The second tappet component 58 is substantially tubular, having a diameter inferior to that of the first tappet component 56 . The end 23 a, inside the casing 8 a, of the second tappet component 58 is provided with an annular tappet stop 59 of enlarged diameter which supports the guiding damping unit 41 a. The end 60 of the first tappet component 56 has an annular stop 61 which is recessed in the shape of a wedge. Between the end 60 and the end 23 a, inside the casing 8 a, of the tappet 17 a, provision is made for the contact-pressure component 30 a with the frictional damping lining 29 a. The contact-pressure-piston component 30 a is a U-shaped ring, bilaterally holding the frictional damping lining 29 a. On the wall of the contact-pressure-piston component 30 a that is turned towards the central longitudinal axis 9 of the casing 8 a, a contact-pressure-piston stop 37 a is provided, which projects radially. The first spring 32 a is pre-loaded between the tappet stop 59 and the wall of the contact-pressure-piston stop 37 a which is turned towards the end 23 a of the tappet 17 a inside the casing 8 a. As opposed to this, the second spring 33 a is pre-loaded between the stop 61 of the tappet component 56 and the wall of the contact-pressure-piston stop 37 a turned towards the end 60 of the tappet component 56 . The first fastening element 12 a and the casing 8 a form two pieces, the fastening element 12 a being united with the free end 10 a of the casing 8 a by positive fit.
[0035] Consequently, the first fastening element 12 a constitutes the bottom 11 a of the casing 8 a. The second tappet component 58 and the guiding damping unit 41 a are going to be described in detail below. The second tappet component 58 has a tubular basic tappet structure 62 , the end 63 of which tapers, with two fastening projections 64 being disposed thereon, which extend in the direction of the central longitudinal axis 18 of the tappet 17 a, each having a fastening nose 65 . The disk-shaped tappet stop 59 is integral with the basic tappet structure 62 and the guiding damping unit 41 a. Various reinforcing elements are provided inside the basic tappet structure 62 , which are not going to be explained in detail.
[0036] The guiding damping unit 41 a is composed of six damping elements 50 a of annular arrangement, which face each other diametrically and are spaced from, and uniformly distributed relative to, the central longitudinal axis 18 a of the tappet 17 a. Each damping element 50 a comprises an inner rib portion 51 a and an outer rib portion 52 a, the outer rib portion 52 a being bent by an outside radius and the inner rib portion 51 a by an inside radius, and the inside radius exceeding the outside radius. The inner rib portion 51 a centrally comprises a stop 55 a that projects radially in the direction of the outer rib portion 52 a. Each damping element 50 a is symmetrical of a plane that intersects the central longitudinal axis 18 of the tappet 17 a and the tip of the stop 55 a which belongs to the damping element 50 a. The outer rib portion 52 a is bilaterally connected to the inner rib portion 51 a via a connecting-rib portion 53 a such that the individual rib portions pass seamlessly into each other. The portions 51 a, 52 a and 53 a enclose a double-reniform chamber 66 which is open only in the axial direction. The outside diameter DSA of the guiding damping unit 41 a is defined as the maximal distance from each other of two opposed outer rib portions 52 a in the relaxed condition seen in FIGS. 6 and 7 . The casing 8 a has an inside diameter D GI . D SA <D GI applies, which means that there is always some play between the portions 52 a and the inside wall of the casing 17 a.
[0037] The mode of operation of the damper 5 a is analogous to that of the first embodiment. In the case of actuation of the tappet 17 a by suddenly rising load in the direction of the central longitudinal axis 9 of the casing 8 a, the only difference resides in that the frictional damping lining 29 a bears by friction against the inside wall of the casing 8 a and guidance of the guiding damping unit 41 a takes place on the inside wall of the casing 8 a. In the second case of an existing transverse-load component, the deflection of the tappet 17 a is also damped by the guiding damping unit 41 a and the tappet 17 a is centered relative to the central longitudinal axis 9 of the casing 8 a. Assuming that the transverse-load component acts on the plane that intersects the central longitudinal axis 18 of the tappet 17 a and the tip of the stop 55 a of a damping element 50 a, the outer rib portion 52 a of the respective damping element 50 a is being moved flexibly in the direction of the central longitudinal axis 18 of the tappet 17 a so that spring load builds up, counteracting the transverse-load component. As a result, the deflection of the tappet 17 a crosswise of the central longitudinal axis 18 is being braked until there is reversion of the motion of the tappet 17 a. The outer rib portion 52 a now moves from the central longitudinal axis 18 radially outwards. Owing to friction losses in the material of the damping elements 50 a and friction losses between the guiding damping unit 41 a and the inside wall of the casing 8 a, the vibratory operation crosswise of the central longitudinal axis 18 that is performed by the tappet 17 a is being damped so that the tappet 17 a is again centered relative to the central longitudinal axis 9 of the casing 8 a after disappearance of the transverse-load component. In case of a transverse-load component of great amplitude, the motion of the outer rib portion 52 a is defined by the stop 55 a.
[0038] The following is a description of a third embodiment of the invention, taken in conjunction with FIGS. 8 and 9 . Identical parts have the same reference numerals as in the first embodiment, to the description of which reference is made. Parts that differ in construction, but are functionally identical, have the same reference numerals with a b annexed. The substantial difference from the first embodiment resides in the configuration of the guiding damping unit 41 b. Like in the first embodiment, the guiding damping unit 41 b is fixed to the cap 39 b. Unlike the first embodiment, the cap 39 b is not pushed over the casing cup 27 but into it so that the locking noses 43 b that are disposed on the cap 39 b stand out radially, snap-engaging from inside with corresponding recesses in the casing cup 27 . The cap 39 b comprises four damping elements 50 b which are uniformly distributed along the circumference and project inwards from an annular edge 68 . The inner rib portion 51 b as well as the connecting rib portions 53 b constitute a flexibly compressible spring arm or bow which projects inwards in the shape of a bow. It encloses a chamber 66 b of oval cross-sectional shape which is open only in the axial direction. Between two adjacent damping elements 50 b, provision is made for a guide rib 69 which projects inwards from the edge 68 and the inner surfaces 70 of which that are turned towards the axis 47 have the cross-sectional shape of a radius around the axis 47 . The diameter in the vicinity of two opposed inner rib portions 51 b is designated by D BI . The diameter in the vicinity of two opposed guide ribs 69 is designated by D FI . D FI >D BI applies, which means that the inner rib portions 51 b stand out further in the direction towards the axis 47 than the inner surfaces 70 of the guide ribs 69 . The tappet 17 has some play towards the portions 51 b. Consequently, the tappet 17 , when tilted, first rests on the inner rib portions 51 b. If it is more strongly tilted, guidance of the tappet 17 is ensured by the inner surfaces 70 . A groove 71 of substantially radial extension is arranged between a damping element 50 b and a guide rib 69 , freeing the curved connecting rib portion 53 b and offering sufficient space for deformation of the rib portion 53 b upon compression.
[0039] As regards the mode of operation of the guiding damping unit 41 b, reference is made to the explanations of the first embodiment. Advantages reside in that the damping elements 50 b are able to take deformations more easily, because they are not connected by a joint inner ring 67 as in the first embodiment. Moreover, the guide ribs 69 provide for stable guidance in the case of stronger tilting.
[0040] A fourth embodiment of the invention will be described below, taken in conjunction with FIGS. 10 and 11 . Identical parts have the same reference numerals as in the first embodiment, to the description of which reference is made. Parts that differ in construction, but are functionally identical, have the same reference numerals with a c annexed. The cap 39 c has the same design as the cap 39 b of the third embodiment with only one exception. The only difference consists in that, in the middle, the inner rib portions 51 c are interrupted by a gap 72 . In other words, the damping element 50 c is formed by two arcs 73 of the cross-sectional shape of quarter circles which are turned towards each other and the free ends of which define the gap 72 . An advantages of this arrangement resides in that less force is needed for compressing the arcs 73 in the radial direction. Consequently, more solid materials which are advantageous for the rest of the cap 39 c, such as POM, can be used without any change in the damping behaviour.
[0041] As regards the mode of operation of the fourth embodiment, reference is made to the third embodiment and thus also to the first embodiment.
[0042] The following is a description of a fifth embodiment of the invention, taken in conjunction with FIGS. 12 and 13 . Identical parts have the same reference numerals as in the first embodiment, to the description of which reference is made. Parts that differ in construction, but are identical functionally, have the same reference numerals with a d annexed. The fifth embodiment has substantially the same design as the second embodiment according to FIGS. 5 to 7 . The only difference resides in that the outer rib portion 52 d is centrally interrupted by a gap 72 d, as a result of which the two parts of the rib portion 52 d become more flexible, offering the same advantages as in the fourth embodiment according to FIGS. 10 and 11 . Like in the second embodiment, a groove 71 d is provided between adjacent damping elements 50 d, the groove 71 d being defined by adjacent rib portions 53 d. Unlike the second embodiment, the stop 55 d is flattened, meaning that it possesses a saddle 74 which the free ends of the parts of the rib portions 52 d will rest on in case of strong compression. As regards the mode of operation, reference is made to the description of the second embodiment.
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In a damper, in particular for spin-drying cylinder washing machines, it is provided, with a view to obtaining low-noise and low-wear guidance of a tappet in a casing, that the damper comprises a guiding damping unit which damps any deflections of the tappet in the radial direction and centers the tappet in the casing.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of (1) U.S. Provisional Patent Application having serial No. ______ (Attorney Docket No. SUNMP013+), filed on May 16, 2001, entitled “System and Method for Compatibility Testing in a Java Environment,” and (2) U.S. Provisional Patent Application having serial No. ______ (Attorney Docket No. SUNMP015+), filed on May 18, 2001, entitled “System and Method for Combinatorial Test Generation in a Compatibility Testing Environment.” Each of these provisional patent applications is incorporated herein by reference. This application is also related to (1) U.S. patent application Ser. No. ______ (Attorney Docket No. SUNMP013), filed Jun. 14, 2001, and entitled “System and Method for Specification Tracking in a Java Compatibility Testing Environment, ” and (2) U.S. patent application Ser. No. ______ (Attorney Docket No. SUNMP016), filed Jun. 14, 2001, and entitled “System and Method for Automated Assertion Acquisition in a Java Compatibility Testing Environment.” Each of these related patent applications is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to general software testing, and more particularly to combinatorial test generation for compatibility testing of Java technologies.
[0004] 2. Description of the Related Art
[0005] Currently, Java environments can be categorized into various Java technologies. A Java technology is defined as a Java specification and its reference implementation. Examples of Java technologies are Java 2 Standard Edition (J2SE), Java 2 Enterprise Edition (J2EE), and Mobile Information Device Profile (MIDP). As with most other types of Java software, a new Java technology should be tested to assure consistency across multiple platforms. This testing is generally performed using compatibility testing.
[0006] Compatibility testing refers to the methods used to test an implementation of a Java technology specification in order to assure consistency across multiple hardware platforms, operating systems, and other implementations of the same Java technology specification. When this assurance is accomplished by means of a formal process, application developers can then be confident that an application will run in a consistent manner across all tested implementations of the same Java technology specification. This consistent specification-based behavior is a primary function of compatibility testing.
[0007] The process of developing compatibility tests for a fairly large API is usually a multi-month process that includes the development of a number of related components. Unlike product testing, which can begin as soon as some part of the program is written, compatibility testing requires both a working implementation and an accurate, complete specification in order to complete the test development process.
[0008] [0008]FIG. 1 is a flow diagram showing a prior art process 100 for creating compatibility tests. As shown in process 100 , a Java specification 102 is processed to create a set of relatively small testable assertions 104 . Statements are generally considered testable assertions if they are intended to describe behavior of an API and can be tested by compatibility tests. Also, examples or sample code pieces that are provided in the specification are typically testable and can be verified by the compatibility tests. In this sense, examples or sample code are generally considered testable assertions.
[0009] On the other hand, statements intended to describe the behavior of an API, but which cannot be tested by compatibility tests due to the special nature of the behavior or functionality, are generally considered non-testable assertions. Similarly, some statements form general descriptions of the API such as a description of a package, class, method, or field, and so forth. If such a general description does not describe behavior, but is aimed rather at providing a context for the rest of the text, then such a statement generally is not intended to be an assertion. Hence, these statements are generally not considered to be assertions due to their nature.
[0010] Once the set of testable assertions 104 is obtained, one or more tests 106 for each assertion is written. Unfortunately, it is not always clear in conventional compatibility testing exactly what should be tested in each assertion and how many tests should be written for each assertion. Theoretically, every logical entity in the assertion could be tested and an infinite number of tests could be written to fully test the assertion. But in practice this, of course, is not affordable.
[0011] In view of the foregoing, there is a need for methods providing improved compatibility test generation. The methods should generate compatibility tests that utilize the least number of combinations of assertion entities provide an acceptable quality of testing of the assertion.
SUMMARY OF THE INVENTION
[0012] Broadly speaking, the present invention fills these needs by providing combinatorial test generation systems and methods that generate compatibility tests using a slot tree. The slot tree of the embodiments of the present invention allows efficient test generation, while providing a means to easily select assertion variable value combinations that seem most appropriate for good quality of testing in each particular case. In one embodiment, a method for combinatorial test generation is disclosed. An assertion is obtained from a specification, wherein the assertion includes a plurality of assertion variables. Next, a slot tree is provided having a plurality of nodes, wherein each node represents an assertion variable. The nodes of the slot tree are then processed to generate tests for the assertion. Optionally, each node can further include a value set having a plurality of values for the assertion variable represented by the node. Also, the plurality of nodes can include nodes that are leaf slots, which represent an actual assertion variable. The plurality of nodes can also include nodes that are non-leaf slots, which are used to construct combination generators from other nodes.
[0013] In another embodiment, a combinatorial test generator tree structure is disclosed. The combinatorial test generator tree structure includes a plurality of leaf slot nodes that represent actual assertion variables, wherein each leaf slot node includes a value set for the assertion variable that the leaf slot node represents. Also included is a plurality of non-leaf slot nodes that are capable of referencing other nodes, wherein the other nodes can be leaf slot nodes and non-leaf slot nodes. The non-leaf slot nodes are used to construct combination generators from the other nodes by combining the value sets of the leaf slot nodes. Optionally, a portion of the non-leaf slot nodes can include all possible combinations of the value sets of child nodes, and a portion of the non-leaf slot nodes can include a portion of all possible combinations of the value sets of child nodes. Also optionally, the portion of all possible combinations of the value sets of child nodes can include every value in the value sets of each of the child nodes. The nodes can be Java objects based on Java slot classes that include combining method calls that determine how the child nodes are combined.
[0014] A computer program for combinatorial test generation embodied on a computer readable medium is disclosed in a further embodiment of the present invention. The computer program includes a code segment that obtains an assertion, wherein the assertion includes a plurality of assertion variables, and a code segment that generates a slot tree having a plurality of nodes, wherein the slot tree represents the assertion variables of the obtained assertion. Further included is a code segment that processes the nodes of the slot tree to generate tests for the assertion. As above, the slot tree can comprise a plurality of leaf slot nodes that represent the actual assertion variables, each leaf slot node including a value set for the assertion variable that the leaf slot node represents. The slot tree can also include a plurality of non-leaf slot nodes that are capable of referencing other nodes, wherein the other nodes can be leaf slot nodes and non-leaf slot nodes.
[0015] Advantageously, the embodiments of the present invention provide combinatorial test generation in an efficient manner provides a means to easily select assertion variable value combinations that seem most appropriate for good quality of testing in each particular case. Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The invention, together with further advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
[0017] [0017]FIG. 1 is a flow diagram showing a prior art process for creating compatibility tests;
[0018] [0018]FIG. 2 is a flowchart showing a method for generating combinatorial tests for an assertion, in accordance with an embodiment of the present invention;
[0019] [0019]FIG. 3 is a diagram showing a slot tree, in accordance with an embodiment of the present invention;
[0020] [0020]FIG. 4 is a diagram showing an exemplary slot tree, in accordance with an embodiment of the present invention;
[0021] [0021]FIG. 5 is a block diagram showing a Java program generation process for use in compatibility test generation, in accordance with an embodiment of the present invention;
[0022] [0022]FIG. 6 is a block diagram showing a Java preprocessor and compiler system, in accordance with an embodiment of the present invention;
[0023] [0023]FIG. 7 is a block diagram showing a Java preprocessor, in accordance with an embodiment of the present invention; and
[0024] [0024]FIG. 8 is a block diagram showing the module decomposition of the test generation library, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] An invention is disclosed for a combinatorial test generator. The embodiments of the present invention test assertions by finding and marking all logically significant parts of the assertion, determining the set of possible values for every found assertion variable, and writing a set of tests, varying the values of the assertion variables from test to test. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention.
[0026] [0026]FIG. 1 was described in terms of the prior art. FIG. 2 is a flowchart showing a method 200 for generating combinatorial tests for an assertion, in accordance with an embodiment of the present invention. In an initial operation 202 , preprocess operations are performed. Preprocess operations include obtaining assertions from a specification and other preprocess operations that will be apparent to those skilled in the art.
[0027] In operation 204 , the assertion is parsed to obtain assertion variables. As mentioned above, an assertion is a statement that is intended to describe behavior of an API and that can be tested by compatibility tests. An assertion variable is a logically significant portion of the assertion. Hence, during operation 204 , all logically significant portions of the assertion are determined and marked as assertion variables. This can be performed manually or through the use of a specialized code module.
[0028] A set of values is then determined for each assertion variable, in operation 206 . As above, operation 206 can be performed manually or through the use of a specialized code module. In any particular assertion, each assertion variable of that assertion generally can have any of a plurality of values. Thus, in operation 206 , these values are determined for each assertion variable of the subject assertion. Moreover, an assertion variable can correspond to several logical entities in the assertion, each having their own value set. In this case, the number of elements in all such value sets should be equal and will be iterated synchronously. For example, if tests should check how a compiler reacts to different brackets with something in between, such a compound assertion variable (slot) can be created whose values consist of pairs: ‘(’ ‘)’, ‘[’ ‘]’, ‘{’ ‘}’, ‘<’ ‘>’. Each “subslot's” (first/second element of current pair) value is programmatically accessible from the test's code.
[0029] Then, in operation 208 , a set of tests for the assertion variables is created. The set of tests preferably varies the values of each assertion variable to better test the assertion, as described in greater detail subsequently. If processing an assertion yielded N assertion variables V1, . . . , Vn with corresponding values sets S1, . . . Sn, then the maximum number (Tmax) of tests would be equal to the number of all possible combinations (C1, . . . , Cn), where Ci runs true all values in the ith value set, namely:
Tmax=|S1|* . . . *|Sn|,
[0030] where |Si| is the number of values in the i'th value set
[0031] In many cases Tmax would be too big to write Tmax tests. So, some methods for creating reasonable number of assertion variable value combinations must be developed. As described in greater detail below, the embodiments of the present invention utilize “slot trees” to generate compatibility tests having a number of assertion variable value combinations that ensure every value of each assertion variable is tested.
[0032] Post process operations are then performed in operation 210 . Post process operations include executing the compatibility tests and other post process operations that will be apparent to those skilled in the art. In general, a combination can be defined as a point in n-dimensional space, where n is the number of assertion variables and i-th coordinate of the point is the index of the value of the i-th assertion variable in this combination. Hence, the number ways in which the set of combinations can be selected for testing the underlying assertion can be very large (with big n's and large value sets).
[0033] As mentioned above, embodiments of the present invention utilize “slots” to create compatibility tests. FIG. 3 is a diagram showing a slot tree 300 , in accordance with an embodiment of the present invention. The slot tree 300 includes leaf slots 302 referenced by a non-leaf slot 304 . Slots represent the assertion variables with their respective value sets and they also incorporate features for generating assertion variable value combinations. Slots can be of two basic types, namely, leaf slots 302 and non-leaf slots 304 .
[0034] Leaf slots 302 are slots that actually represent an assertion variable, and their value set is the value set of the corresponding assertion variable. Non-leaf slots 304 are used to construct combination generators from other slots, which can be either leaf slots 302 or other non-leaf slots 304 . Even leaf slots are combination generators: the number of combinations they generate equals the size of the leaf slot's value set and each combination is a singleton comprised of a slot's value. The user can control the manner in which slots are combined to form higher-level, non-leaf slots, by selecting an appropriate method for combining slots.
[0035] [0035]FIG. 4 is a diagram showing an exemplary slot tree 400 , in accordance with an embodiment of the present invention. The exemplary slot tree 400 includes leaf slots s 1 302 a and s 2 302 b referenced by non-leaf slot 304 a, and non-leaf slot 304 b, which references both non-leaf slot 304 a and leaf slot s 3 302 c. Further, in this example, the three leaf slots s 1 , s 2 , and s 3 have the following values:
[0036] Slot s 1 −new Slot(new String[] {“11”, “12”, “13”});
[0037] Slot s 2 =new Slot(new String[] {“21”, “22”});
[0038] Slot s 3 =new Slot(new String[] {“31”, “32”, “33”, “34”});
[0039] Using the leaf slots s 1 , s 2 , non-leaf slot 304 a can be created. In this case, non-leaf slot 304 a can be created by combining s 1 and s 2 to produce all possible combinations of these slots:
[0040] Slot full_gen=Slot.multiplyFull(s 1 , s 2 );
[0041] Thus, the value set of the non-leaf slot 304 a is now a set of pairs:
[0042] {“11”, “21”} {“11”, “22”}
[0043] {“12”, “21”} {“12”, “22”}
[0044] {“13”, “21”} {“13”, “22”}
[0045] Having created non-leaf slot 304 a, a new non-leaf slot 304 b can be created by combining non-leaf slot 304 a and leaf slot s 3 302 c. Using the embodiments of the present invention, non-leaf slot 304 b can be created such that the least number of combinations are used that ensure every value of each of its child slots occurs at least once.
[0046] Slot pseudo_full_gen=Slot.multiplyPseudoFull(full_gen, s 3 );
[0047] The number of combinations produced by non-leaf slot 304 b is the maximum size of a value set of its child—six in this case. Each combination, generated by the non-leaf slot 304 b is now a triple:
[0048] {“11”, “21”,“31”} {“11”, “22”, “32”}
[0049] {“12”, “21”, “33”} {“12”, “22”, “34”}
[0050] {“13”, “21”, “31”} {“13”, “22”, “32”}
[0051] In general, non-leaf slots 304 can have an arbitrary number of children of arbitrary (leaf, non-leaf) kind. Further, the embodiments of the present invention can use additional “combining” methods other than multiplyFull and multiplyPseudoFull.
[0052] In the embodiments of the present invention, the slots are usually used together with Java preprocessor technology to generate tests. A single template is written where the necessary slot tree is constructed, and then a method of the slot's tree root that processes the slot tree is invoked in a cycle until it returns false. The number of tests equals the number of method invocations. Inside this main cycle current values of the leaf-slots constituting the slot tree can be easily accessed via the Slot's method calls. Non-meta code within the loop bounds accesses the values of slots via macro calls.
[0053] [0053]FIG. 5 is a block diagram showing a Java program generation process 500 for use in compatibility test generation, in accordance with an embodiment of the present invention. The Java program generation process 500 shows a Java template text file 502 , a Java preprocessor and compiler system 504 , a Java byte-codes file 506 , and a Java virtual machine 508 . As mentioned above, the Java template text file 502 comprises a Java language program and meta code for use with the Java preprocessor to create compatibility tests.
[0054] In operation, the Java template text file 502 is provided to the Java preprocessor and compiler system 504 , which preprocesses and compiles the Java template text file 502 . The Java preprocessor and compiler system 504 generates a Java byte-codes file 506 , which can then be executed on any Java enabled platform having a Java virtual machine 508 . The Java virtual machine 508 is used as an interpreter to provide portability to Java applications. In general, developers design Java applications as hardware independent software modules, which are executed by Java virtual machines. The Java virtual machine layer is developed to operate in conjunction with the native operating system of the particular hardware on which the mobile multimedia framework system is to run. In this manner, Java applications can be ported from one hardware device to another without requiring updating of the application code.
[0055] Unlike most programming languages, in which a program is compiled into machine-dependent, executable program code, Java classes are compiled into machine independent byte-code class files 506 , which are executed by a machine-dependent virtual machine 508 . The Java virtual machine 508 provides a level of abstraction between the machine independence of the byte-code classes and the machine-dependent instruction set of the underlying computer hardware. A class loader is responsible for loading the byte-code class files as needed, and an interpreter or just-in-time compiler provides for the transformation of byte-codes into machine code.
[0056] Hence, Java is an interpreted language. The source code of a Java program is compiled into an intermediate language called “bytecode”. The bytecode is then converted (interpreted) into machine code at runtime. Thus, Java programs are not dependent on any specific hardware and will run in any computer with the Java Virtual Machine 508 software.
[0057] [0057]FIG. 6 is a block diagram showing a Java preprocessor and compiler system 504 , in accordance with an embodiment of the present invention. The Java preprocessor and compiler system 504 includes a Java macro preprocessor 600 and a Java compiler 604 . The Java macro preprocessor 600 of the embodiments of the present invention allows preprocessing of Java language program text files 502 . Similar to preprocessors for other programming languages, the Java macro preprocessor 600 of the embodiments of the present invention allows Java language program text files 502 to be processed prior to compilation. This provides greater flexibility in program development, such as allowing conditional compiling. However, unlike prior art preprocessors, the Java macro preprocessor 600 of the embodiments of the present invention advantageously uses the Java programming language as its meta language.
[0058] In use, the Java macro preprocessor 600 receives the Java template 502 , which includes Java meta language. The Java macro preprocessor 600 then processes the Java template 502 to produce a Java object text file 602 . The Java object text file 602 is essentially a Java program that can be compiled by a Java compiler. For example, if the Java template file 502 included a conditional compiling directive to compile one of two blocks of code depending on a particular condition, then the Java object text file 602 would include one of the blocks of code. In some embodiments, the other block of code would not be placed in the Java object text file 602 , while in other embodiments, the block of code could be set off as a comment, which would not be compiled.
[0059] The Java object text file 602 is then provided to the Java compiler 604 , which compiles the Java object text file 602 to generate a Java byte-codes file 506 . As mentioned above, the Java macro preprocessor 600 of the embodiments of the present invention advantageously uses the Java programming language as its meta language. The Java meta language used by the Java macro preprocessor 600 allows the meta language preprocessor directives to be as flexible and powerful as the Java programming language itself.
[0060] [0060]FIG. 7 is a block diagram showing a Java preprocessor 600 , in accordance with an embodiment of the present invention. The Java preprocessor 600 includes an executor module 702 , a test generation library 704 , an object text generator module 706 , a preprocessor library interface module 708 , and a meta code converter module 710 .
[0061] The Java preprocessor 600 includes two core modules that implement the preprocessor itself, namely, the meta code converter module 710 and the object text generator module 706 . The meta code converter module 710 includes a main class, JmppReader, and auxiliary classes, which can be defined in the same source file. The meta code coverter module 710 transforms a single line of a template code into a line of the intermediate program code. Note that the intermediate program includes not only lines resulted from the ‘template line’->‘intermediate program line’ conversion. The intermediate program also includes lines generated by the object text generator module 706 .
[0062] The object text generator module 706 includes a main class, JmppLib, and auxiliary classes, which can be defined in the same source file. The object text generator module 706 is the main module of the preprocessor 600 , and is responsible for the intermediate program's prolog and epilog code generation, and the compiling of the intermediate program (using a Java compiler). The object text generator module 706 is also responsible for running the intermediate program, which actually generates the object text file. The main class of the object text generator module 706 also serves as a super class for any preprocessor libraries, which are extensions that use the preprocessor engine for more specific purposes, such as for generating a number of tests from a single template.
[0063] The Java preprocessor 600 further includes two additional modules that extend the preprocessor's functionality, namely, the preprocessor library interface module 708 and the executor module 702 . The preprocessor library interface module 708 typically includes a single interface. The preprocessor library interface module 708 specifies a contract that should be implemented by any Java preprocessor library, such as the test generation library 704 , that is to be supported. This interface exposure allows the preprocessor to be usable inside other Java applications, such as a test development kit. There are two levels of support that a preprocessor library can request from an interactive test development system, basic and full. The basic support level generally only supports test generation. The full support level supports the basic level plus a template creation wizard.
[0064] The executor module 702 typically includes a single class that allows the executor module 702 to preprocess templates using an object text generator different from the default one described above. The executor module 702 calculates the object text generator class name based on the first template line and the command line options, loads the object text generator class, and invokes main method of the object text generator class.
[0065] The test generation 704 library is the engine behind the Java preprocessor, allowing the test developer to dynamically expand java and .html files from a single test template instead of writing Java and .html files manually. In this manner, embodiments of the present invention can ensure the generated Java and .html files are created according to format specified as well as avoid code/text duplication. An output format can vary upon user's needs so the user can create java and .html files in a different format using a single template. Also, the user can use parametrized test generation to create a set of similar tests from a single block of code. Test templates can use a jmpp extension by convention. The output formats of the generated java and .html files correspond to the JavaTest harness requirements.
[0066] [0066]FIG. 8 is a block diagram showing the module decomposition of the test generation library 704 , in accordance with an embodiment of the present invention. The test generation library includes a data control module 800 , an internal representation module 802 , a generation module 804 , a customizing module 806 , and an error handling module 808 . Each of the modules of the test generation library 704 comprises internal classes, methods and corresponding variables that are specific to each individual module.
[0067] More specifically, the data control module 800 provides a number of methods that control the correctness and completeness of the corresponding data set. The test generation library 704 distinguishes three levels of the given template context hierarchy, namely, Directory Level, File Level, and Test Level. Every level has its specific set of mandatory, optional variables or variables-switches. The internal representation module 802 comprises a number of internal classes representing template entities such as, Method, Test case, and Test Description. This information is then used at the java and .html files generation step.
[0068] The customizing module 806 is responsible for the test generation process customization. Specifically, the customizing module 806 provides methods for property file processing and inline customization from the template. The error handling module 808 provides a number of classes to represent exceptional situations, and a generation module 804 is responsible for actual java and .html files generation.
[0069] The invention may employ various computer-implemented operations involving data stored in computer systems. These operations are those requiring physical manipulation of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. Further, the manipulations performed are often referred to in terms, such as producing, identifying, determining, or comparing.
[0070] Any of the operations described herein that form part of the invention are useful machine operations. The invention also relates to a device or an apparatus for performing these operations. The apparatus may be specially constructed for the required purposes, or it may be a general purpose computer selectively activated or configured by a computer program stored in the computer. In particular, various general purpose machines may be used with computer programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform the required operations.
[0071] The invention can also be embodied as computer readable code on a computer readable medium. The computer readable medium is any data storage device that can store data which can be thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, hard disks, removable cartridge media, CD-ROMs, magnetic tape, optical data storage devices. The computer readable medium can also be distributed over a network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.
[0072] Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.
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A computer program embodied on a computer readable medium is provided for combinatorial test generation. The computer program includes a code segment that obtains an assertion, wherein the assertion includes a plurality of assertion variables, and a code segment that generates a slot tree having a plurality of nodes, wherein the slot tree represents the assertion variables of the obtained assertion. Further included is a code segment that processes the nodes of the slot tree to generate tests for the assertion. As above, the slot tree can comprise a plurality of leaf slot nodes that represent the actual assertion variables, each leaf slot node including a value set for the assertion variable that the leaf slot node represents. The slot tree can also include a plurality of non-leaf slot nodes that are capable of referencing other nodes, wherein the other nodes can be leaf slot nodes and non-leaf slot nodes.
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RELATED APPLICATIONS
[0001] This application is a continuation of prior U.S. patent application Ser. No. 10/007,053, filed Dec. 3, 2001, which is a continuation of prior U.S. patent application Ser. No. 09/263,924, filed Mar. 5, 1999, which is a continuation of U.S. patent application Ser. No. 08/854,547, filed May 12, 1997, which is a continuation of U.S. patent application Ser. No. 07/967,700, filed Oct. 27, 1992, now U.S. Pat. No. 5,628,930.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to emulsions comprising highly fluorinated or perfluorinated compounds. More particularly, it relates to fluorocarbon emulsions having superior particle size stability during storage.
[0003] Fluorocarbon emulsions find uses as therapeutic and diagnostic agents. Most therapeutic uses of fluorocarbons are related to the remarkable oxygen-carrying capacity of these compounds. One commercial biomedical fluorocarbon emulsion, Fluosol (Green Cross Corp., Osaka, Japan), is presently used as a gas carrier to oxygenate the myocardium during percutaneous transluminal coronary angioplasty (R. Naito, K. Yokoyama, Technical Information Series No. 5 and 7, 1981). Fluorocarbon emulsions have also been used in diagnostic applications such as imaging. Radiopaque fluorocarbons such as perflubron (perfluorooctyl bromide or C 8 F 17 Br) are particularly useful for this purpose.
[0004] It is important that fluorocarbon emulsions intended for medical use exhibit particle size stability. Emulsions lacking substantial particle size stability are not suitable for long term storage, or they require storage in the frozen state. Emulsions with a short shelf life are undesirable. Storage of frozen emulsions is inconvenient. Further, frozen emulsions must be carefully thawed, reconstituted by admixing several preparations, then warmed prior to use, which is also inconvenient.
[0005] Davis et al., U.S. Pat. No. 4,859,363, disclose stabilization of perfluorodecalin emulsion compositions by mixing a minor amount of a higher boiling perfluorocarbon with the perfluorodecalin. Preferred higher boiling fluorocarbons were perfluorinated saturated polycyclic compounds, such as perfluoroperhydrofluoranthene. Others have also utilized minor amounts of higher boiling fluorocarbons to stabilize emulsions. See, e.g., Meinert, U.S. Pat. No. 5,120,731 (fluorinated morpholine and piperidine derivatives), and Kabalnov, et al., Kolloidn Zh. 48: 27-32 (1986)(F—N-methylcyclohexylpiperidine).
[0006] Davis, et al. suggested that the primary phenomenon responsible for instability of small particle size fluorocarbon emulsions was Ostwald ripening. During Ostwald ripening, an emulsion coarsens through migration of molecules of the discontinuous phase from smaller to larger droplets. See generally, Kabalnov, et al., Adv. Colloid Interface Sci. 38: 62-97 (1992). The force driving Ostwald ripening appears to be related to differences in vapor pressures that exist between separate droplets. Such a difference in vapor pressure arises because smaller droplets have higher vapor pressures than do larger droplets. However, Ostwald ripening may only proceed where the perfluorocarbon molecules are capable of migrating through the continuous phase between droplets of the discontinuous phase. The Lifshits-Slezov equation relates Ostwald ripening directly to water solubility of the discontinuous phase. See Lifshits, et al., Sov. Phys. JETP 35: 331 (1959).
[0007] It is known that addition of higher molecular weight compounds, having lower vapor pressures and lower solubility in the continuous phase, reduces such interparticle migration. This, in turn, reduces Ostwald ripening and improves particle size stability. Thus, the conventional prior art solution to the particle size stability problem is to add a certain amount (e.g., 10-30% of the fluorocarbon content) of a higher molecular weight fluorocarbon to the discontinuous phase.
[0008] Fluorocarbon emulsion particles are taken up and temporarily retained by cells of the reticuloendothelial system (RES). It is desirable to minimize this retention time. Unfortunately, when the prior art included higher molecular weight fluorocarbons in fluorocarbon emulsions, organ retention times were also increased considerably. Organ retention time for most fluorocarbons bears an exponential relationship to the molecular weight of the fluorocarbon. See J. G. Riess, Artificial Organs 8: 44, 49-51; J. G. Riess, International Symposium on Blood Substitutes, Bari, Italy: Jun. 19-20, 1987, Proceedings pp. 135-166.
[0009] There is a need for perfluorocarbon emulsions that exhibit both storage stability in the nonfrozen state and a rapid rate of elimination from the body. Accordingly, it is an object of the invention to provide fluorocarbon emulsions having these characteristics.
SUMMARY OF THE INVENTION
[0010] The present invention involves stabilization of fluorocarbon emulsions with higher molecular weight fluorocarbons that include a lipophilic moiety. Alternatively, any fluorocarbon having a critical solution temperature that is 10EC or more below that which is predicted by its molecular weight can be used to stabilize fluorocarbon emulsions in accordance with this invention.
[0011] A major advantage of the present invention is the surprisingly short organ retention times of the stabilized emulsion. Perfluorodecyl bromide, for example, has a calculated half life in vivo in organs of the reticuloendothelial system (RES) of approximately 18 days, while those of nonlipophilic perfluorocarbons having about the same molecular weight vary from about 50 to 300 days. (See Table IV.) This distinction is critical; it spells the difference between formulations which are physiologically acceptable and those which are not. Note that none of the prior art stabilizers are lipophilic; thus, none share the advantageous properties of the present invention. For example, with reference to Table [V and FIG. 5, the stabilizers of the present invention all have critical solution temperatures (CSTs) and projected organ retention times much lower than those of the prior art stabilizers of Davis, et al., Kabalnov, and Meinert. Aside from the stabilizers of the present invention, conventional fluorocarbons exhibit a direct correlation between retention time in RES organs and molecular weight. Also, aside from the lipophilic fluorocarbons used in the present invention, the perfluorochemical structure has little effect on the strong retention time/molecular weight relationship. Thus, the presence of heteroatoms or cyclic structure has little effect on organ retention time.
[0012] Another major advantage of the present invention over the prior art is that the emulsions are remarkably stable. This is particularly true when both the major (first) fluorocarbon and the stabilizing (second) fluorocarbon include lipophilic moieties.
[0013] Thus, in accordance with one aspect of the present invention, there is provided a storage stable fluorocarbon emulsion, comprising a continuous aqueous phase, an effective amount of an emulsifying agent, and a discontinuous fluorocarbon phase, comprising from about 50% to about 99.9% of a one or more first fluorocarbons, and from about 0.1% to about 50% of one or more second fluorocarbons having a molecular weight greater than each such first fluorocarbon, wherein each such second fluorocarbon includes at least one lipophilic moiety. The first fluorocarbon can be selected from a variety of materials, including bis (F-alkyl) ethenes, perfluoroethers having the general structure C n F 2n+1 —O—C n —F 2n+1 , wherein the sum of n and n′ equals 6 to 8, perfluoromethylbicyclo [3.3.1]-nonane, perfluoro-2,2,4,4-tetramethylpentane, perfluorotripropylamine, bis(F-butyl)ethene, (F-isopropyl) (F-hexyl) ethene, perfluoromethyladamantane, perfluorodimethyladamantane, F—N-methyldecahydroisoquinoline, F-4-methyloctahydroquinolidizine, perfluorodecalin, or most preferably, perfluorooctyl bromide. In one embodiment, each first fluorocarbon has a molecular weight from about 460 Daltons to about 550 Daltons, and also preferably has a half life in vivo of less than about 4 weeks, preferably less than 2 or 3 weeks, and most preferably 7 days or less. In the second fluorocarbon, the lipophilic moiety or moities are advantageously Br, Cl, I, H, CH 3 , or a saturated or unsaturated hydrocarbon chain of 2 or 3 carbon atoms. In one preferred embodiment, the second fluorocarbon is an aliphatic perfluorocarbon having the general formula C n F 2n+1 R or C n F 2n R 2 , wherein n is an integer from 9 to 12 and R is the lipophilic moiety. In various preferred embodiments, the second fluorocarbon is selected from the group consisting of perfluorododecyl bromide, C 10 F 21 CH═CH 2 , or C 10 F 2 ]CH 2 CH 3 , or linear or branched brominated perfluorinated alkyl ethers. Most preferably, the second fluorocarbon comprises perfluorodecyl bromide. It is desirable that each second fluorocarbon has a molecular weight greater than about 550 Daltons. Pursuant to an alternative definition of the second fluorocarbon, each second fluorocarbon has a critical solution temperature in hexane at least 10EC lower than that of a fully fluorinated fluorocarbon having substantially the same molecular weight (i.e., a molecular weight within 10, and preferably within 3, 4, or 5 daltons). In preferred emulsions, the discontinuous fluorocarbon phase comprises from about 60% to about 99.5% of the first fluorocarbon, and from about 0.5% to about 40% of the second fluorocarbon; more preferably from about 80% to about 99% of the first fluorocarbon, and from about 1% to about 20% of the second fluorocarbon. A particularly preferred emulsifier is egg yolk phospholipid, and preferred amounts of this emulsifier are 1%-10% w/v. Also preferred are the fluorinated surfactants.
[0014] Another aspect of the present invention comprises a method for imparting particle size stability to a fluorocarbon emulsion having a discontinuous phase of one or more first fluorocarbons and a continuous aqueous phase, comprising the step of including in admixture with said first fluorocarbon an emulsion-stabilizing amount of one or more second fluorocarbons having a molecular weight greater than said first fluorocarbon, wherein each said second fluorocarbon includes within its structure a lipophilic moiety. In this method, the definitions of the first and second fluorocarbons, the surfactant, and the various emulsion parameters can be the same as for the emulsions discussed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] [0015]FIG. 1 represents accelerated stability testing (T=40EC) for 90% w/v fluorocarbon, 4% w/v egg yolk phospholipid emulsions containing mixtures of perfluorooctyl bromide and perfluorodecyl bromide. The stability of emulsions with 0%, 1%, and 10% w/w perfluorodecyl bromide are presented in plots of diameter cubed (μm 3 ) vs. time (months).
[0016] [0016]FIG. 2 (a-d) represents represents particle size histograms (as obtained by photosedimentation) after three months storage at 40 EC for a 90% w/v fluorocarbon emulsion containing 95/5% w/w mixture of perfluorooctyl bromide to perfluorodecyl bromide prepared under similar conditions to those of FIG. 1. The emulsions are stabilized by 4% w/v egg yolk phospholipid. (Note the emulsion particle diameters as reported on the Figures are not corrected for the vesicle fraction which shows up as a peak in the first histogram bar).
[0017] [0017]FIG. 3 represents accelerated stability testing (T=40EC) for 60% w/v fluorocarbon, 4% w/v egg yolk phospholipid emulsions containing mixtures of perfluorooctyl bromide and perfluorodecyl bromide. The stability of emulsions with 0% and 10% w/w perfluorodecyl bromide are presented in plots of diameter cubed (μm 3 ) vs. time (months).
[0018] [0018]FIG. 4 (a,b) represents a plot of percent mouse lethality vs. dose (ml/kg) for a 3% egg yolk phospholipid, 90% w/v fluorocarbon emulsion containing 90%/10% w/w perfluorooctyl bromide/perfluorodecyl bromide. The LD 50 of this emulsion is approximately 48 ml/kg.
[0019] [0019]FIG. 5 represents a plot of fluorocarbon molecular weight (g/mol) versus critical solution temperature against hexane (EK) for various fluorocarbons including the prior art emulsion stabilizers proposed by Davis, Meinert, and Kabalnov.
[0020] [0020]FIG. 6 is a plot of the organ half-life in days vs. molecular weight of the fluorocarbon in g/mol. Traditionally, the molecular weight region from 460-550 g/mol has been considered optimal for blood substitute applications. The lower cutoff is related to the formation of gas emboli for fluorocarbons with vapor pressures greater than 20 torr. The upper cutoff is limited to compounds with organ retention times of less than 3 weeks. It is clear that the lipophilic compounds do not fit the general trend in that they have shorter organ retention times than would be predicted for their molecular weight. PFDB has a half-life less than the prescribed 3 week cutoff. (Note—because the organ half-life depends on dose and method of measurement, the values for PFOB and PFDB have been scaled relative to F-decalin knowing that the ratio of half-lives for PFOB/FDC=4/7).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Introduction
[0022] The fluorocarbon emulsions of the present invention comprise two phases: a continuous aqueous phase and a discontinuous fluorocarbon phase. Osmotic agents and buffers, generally, are also included in the continuous phase to maintain osmolarity and pH to promote physiological acceptability.
[0023] The discontinuous phase of modern fluorocarbon emulsions for therapeutic use generally comprises from 20% w/v to up to 125% w/v of a fluorocarbon or a highly fluorinated compound (hereinafter referred as a “fluorocarbon” or a “perfluorocarbon”). As used herein, the expression “weight per volume” or “w/v” will mean grams per 100 cubic centimeters or milliliters. Also, as used herein, the expression “weight per weight” or “w/w” will be used and understood to mean the weight fractions of components that add up to give a desired weight per volume.
[0024] The present invention provides stable fluorocarbon emulsions by forming the discontinuous phase from a mixture of at least two fluorocarbons, at least one of which has a relatively higher molecular weight and which includes in its molecular structure a lipophilic moiety. Unlike prior art emulsions in which a higher molecular weight fluorocarbon is included to prevent Ostwald ripening, the present added fluorocarbon(s) are excreted at a rate which is physiologically acceptable. Stable fluorocarbon emulsions with particle sizes as small as ca. 0.1 μm may be prepared, with good particle size stability. Surprisingly, emulsions of the present invention may be stored with little or no particle growth at relatively elevated temperatures of 20EC to 40EC.
[0025] A preferred embodiment utilizes two fluorocarbons; however, the “first” and “second” fluorocarbons discussed below can instead comprise mixtures of fluorocarbons, each of which has the specified characteristics.
[0026] The first fluorocarbon preferably has a molecular weight from about 460 to 550 Daltons and is employed in a relative ratio of 50% to 99.9% by weight. The second fluorocarbon is preferably an aliphatic fluorocarbon, including within its molecular structure at least one lipophilic moiety, and having a molecular weight greater than about 550 Daltons at a relative ratio of 50% to 0.1%. Linear fluorocarbons are preferred for both the first and second fluorocarbons. The second fluorocarbon is preferably terminally substituted with the lipophilic moiety, although substitutions at other positions are also contemplated.
[0027] A first alternative definition of the second fluorocarbon focuses on its critical solution temperature (CST). In accordance with this definition, the second fluorocarbon has a CST that is lower than the CST of a fully fluorinated fluorocarbon (lacking a lipophilic moiety) having substantially the same molecular weight. Preferably, the CST of the second fluorocarbon is at least 10E lower than such a fully fluorinated fluorocarbon.
[0028] A second alternative definition of the second fluorocarbon focuses on its organ retention time. It is possible to predict organ retention time from a log plot of the molecular weight of the fluorocarbon. In the present invention, the second fluorocarbon preferably has an organ retention time that is less than what is predicted by the aforementioned log plot.
[0029] Emulsions may be prepared through the method of the present invention at very high fluorocarbon concentrations (up to 125%, w/v), virtually any desired particle size, and with very low quantities of emulsifying agents, without losing stability. Unlike prior art, stabilized fluorocarbon emulsions, the organ retention time of the added fluorocarbon is well within acceptable limits. Further advantages and attributes are discussed below.
[0030] The Compositions
[0031] A. The Discontinuous Phase
[0032] The characteristics of fluorocarbons suitable for use in the present invention are discussed in more detail below. Examples of suitable fluorocarbons are provided.
[0033] The First Fluorocarbon
[0034] The first fluorocarbon is selected for its short organ retention time and biocompatibility. In general, the half life in organs is preferably less than about 4 weeks, more preferably less than about 2 or 3 weeks, and most preferably 7 days or less. The molecular weight is from about 460 to about 550 daltons.
[0035] Such fluorocarbons include bis(F-alkyl)ethenes such as C 4 F 9 CH═CHC 4 F 9 (“F-44E”), i-CF 3 CF 9 CH═CHC 6 F 13 (“F-i36E”), and cyclic fluorocarbons, such as C 10 F 18 (F-decalin, perfluorodecalin or FDC); F-adamantane (FA); perfluoroindane; F-methyladamantane (FMA); F-1,3-dimethyladamantane (FDMA); perfluoro-2,2,4,4-tetramethylpentane; F-di- or F-tri-methylbicyclo[3,3,1]nonane (nonane); C 7-12 perfluorinated amines, such as F-tripropylamine, F-4-methyloctahydroquinolizine (FMOQ), F-n-methyl-decahydroisoquinoline (FMIQ), F-n-methyldecahydroquinoline (FHQ), F-n-cyclohexylpyrrolidine (FCHP), and F-2-butyltetrahydrofuran (FC-75 or RM101).
[0036] Other examples of appropriate first fluorocarbons include brominated perfluorocarbons, such as perfluorooctyl bromide (C 8 F 17 Br, USAN perflubron), 1-bromopentadecafluoroheptane (C 7 F 15 Br), and 1-bromotridecafluorohexane (C 6 F 13 Br, also known as perfluorohexyl bromide or PFHB. Other brominated fluorocarbons are disclosed in U.S. Pat. Nos. 3,975,512 and 4,987,154 to Long.
[0037] Also contemplated are fluorocarbons having other nonfluorine substituents, such as 1-chloro-heptadecafluorooctane (C 8 F 17 Cl, also referred to as perfluorooctyl chloride or PFOCl); perfluorooctyl hydride, and similar compounds having different numbers of carbon atoms.
[0038] Additional first fluorocarbons contemplated in accordance with this invention include perfluoroalkylated ethers, halogenated ethers (especially brominated ethers), or polyethers, such as (CF 3 ) 2 CFO(CF 2 CF 2 ) 2 OCF(CF 3 ) 2 ; (C 4 F 9 ) 2 O. Further, fluorocarbon-hydrocarbon compounds may be used, such as, for example compounds having the general formula C n F 2n+1 —C n′ H 2n′+1 ; C n F 2n+1 OC n′ H 2n′+1 ; or C n F 2n+1 CH═CHC n′ H 2n′+1 , wherein n and n′ are the same or different and are from about 1 to about 10 (so long as the compound is a liquid at room temperature). Such compounds, for example, include C 8 F 17 C 2 H 5 and C 6 F 13 CH═CHC 6 H 13 .
[0039] Particularly preferred fluorocarbons for use as the first fluorocarbon include perfluoroamines, terminally substituted linear aliphatic perfluorocarbons having the general structure:
[0040] C n F 2n+1 R, wherein n is an integer from 6 to 8 and R comprises a lipophilic moiety selected from the group of Br, Cl, I, CH 3 , or a saturated or unsaturated hydrocarbon of 2 or 3 carbon atoms,
[0041] bis (F-alkyl) ethenes having the general structure:
[0042] C n F 2n+1 —CH═CH—C n′ F 2n′+1 , wherein the sum of n and n′ equals 6 to 10, and
[0043] perfluoroethers having the general structure:
[0044] C n F 2n+1 —O—C n′ F 2n′+1 , wherein the sum of n and n′ equals 6 to 9.
[0045] In addition, fluorocarbons selected from the general groups of perfluorocycloalkanes or perfluoroalkyl-cycloalkanes, perfluoroalkyl saturated heterocyclic compounds, or perfluorotertiary amines may be suitably utilized as the first fluorocarbon. See generally Schweighart, U.S. Pat. No. 4,866,096.
[0046] It will be appreciated that esters, thioethers, and other variously modified mixed fluorocarbon-hydrocarbon compounds, including isomers, are also encompassed within the broad definition of fluorocarbon materials suitable for use as the first fluorocarbon of the present invention. Other suitable mixtures of fluorocarbons are also contemplated.
[0047] Additional fluorocarbons not listed here, but having the properties described in this disclosure that would lend themselves to therapeutic applications, are also contemplated. Such fluorocarbons may be commercially available or specially prepared. As will be appreciated by one skilled in the art, there exist a variety of methods for the preparation of fluorocarbons that are well known in the art. See for example, Schweighart, U.S. Pat. No. 4,895,876.
[0048] The Second Fluorocarbon
[0049] The second fluorocarbon is an aliphatic fluorocarbon substituted with one or more lipophilic moieties and having a higher molecular weight than the first fluorocarbon. Advantageously, the lipophilic moiety is a terminal substitution on the fluorocarbon molecule. Preferably, the molecular weight of the second fluorocarbon is greater than about 540 Daltons. Constraints on the upper limit of the molecular weight of the second fluorocarbon will generally be related to its organ retention time and its ability to be solubilized by the first fluorocarbon. Usually, the second fluorocarbon has a molecular weight less than about 700 Daltons.
[0050] Most preferred second fluorocarbons have boiling points greater than about 150EC and water solubilities of less than about 1×10 −9 moles/liter.
[0051] Of course, as will be appreciated by one skilled in the art, many fluorocarbons substituted with different lipophilic groups could be suitably used as the second fluorocarbon in the present invention. Such fluorocarbons may include esters, thioethers, and various fluorocarbon-hydrocarbon compounds, including isomers. Mixtures of two or more fluorocarbons satisfying the criteria set forth herein are also encompassed within the broad definition of fluorocarbon materials suitable for use as the second fluorocarbon of the present invention. Fluorocarbons not listed here, but having the properties described in this disclosure that would lend themselves to therapeutic applications are additionally contemplated.
[0052] The lipophilic moiety is optimally selected from the group consisting of Br, Cl, I, CH 3 , or a saturated or unsaturated hydrocarbon of 2 or 3 carbon atoms. Consequently, preferred second fluorocarbons may be selected from the group of terminally substituted perfluorocarbon halides as represented by the general formula:
[0053] C n F 2n+1 X or C n F 2n X 2 , wherein n is 8 or greater, preferably 10 to 12, and X is a halide selected from the group consisting of Br, Cl, or I;
[0054] 1-alkyl-perfluorocarbons or dialkylperfluorocarbons as represented by the general formula:
[0055] C n F 2n+1 —(CH 2 ) n′ CH 3 wherein n is 8 or greater, preferably 10 to 12, and n′ is 0 to 2;
[0056] 1-alkenyl-perfluorocarbons as represented by the general formula:
[0057] C n F 2n+1 —C n′ H (2n′−1 , wherein n is 10 or more, preferably 10 to 12, and n′ is either 2 or 3; or
[0058] brominated linear or branched perfluoroethers or polyethers having the following general structure:
[0059] Br—(C n F 2n+1 —O—C n′ F 2n′+1 ), wherein n and n′ are each at least 2 and the sum of n and n′ is greater than or equal to 8.
[0060] Most preferably, the second fluorocarbon of the present invention is selected from the group consisting of linear or branched brominated perfluorinated alkyl ethers, perfluorodecyl bromide (C 10 F 21 Br); perfluorododecyl bromide (C 12 F 25 Br); 1-perfluorodecylethane (C 10 F 21 CH═CH 2 ); and 1-perfluorodecylethene (C 10 F 21 CH 2 CH 3 ); with perfluorodecyl bromide particularly preferred.
[0061] In accordance with a first alternative definition, whether or not they satisfy the foregoing definitions, fluorocarbons having critical solution temperatures (CSTs) vs hexane more than 10EC below the CST of a fluorocarbon having substantially the same molecular weight (variations of up to about 10 daltons being acceptable) are also suitable for use in the present invention. A comparison between the CST and molecular weight of a number of perfluorocarbons is presented in Table IV, below. Methodology for determining CST is presented in Example 9.
[0062] A second alternative definition of the second fluorocarbon is evident from FIG. 6 and Example 8. Suitable second fluorocarbons may be selected from those which have significantly lower half lives than nonlipophilic fluorocarbons of substantially the same molecular weight. As is evidenced in FIG. 6, the log of the half life in days of suitable second fluorocarbons can be at least 0.2, preferably at least 0.3, and more preferably at least 0.4 or 0.5 less than the average or expected value for nonlipophilic fluorocarbons of substantially the same molecular weight.
[0063] The Emulsifying Agent
[0064] The fluorocarbon emulsions also include an emulsifying agent. As used in this specification, an emulsifying agent is any compound or composition that aids in the formation and maintenance of the droplets of the discontinuous phase by forming a layer at the interface between the discontinuous and continuous phases. The emulsifying agent may comprise a single compound or any combination of compounds, such as in the case of co-surfactants.
[0065] In the present invention, preferred emulsifying agents are selected from the group consisting of phospholipids, nonionic surfactants, fluorinated surfactants, which can be neutral or anionic, and combinations of such emulsifying agents.
[0066] Lecithin is a phospholipid that has frequently been used as a fluorocarbon emulsifying agent, as is more fully described in U.S. Pat. No. 4,865,836. Egg yolk phospholipids have shown great promise as emulsifying agents for fluorocarbons. See e.g., Long, U.S. Pat. No. 4,987,154.
[0067] Other emulsifying agents may be used with good effect, such as fluorinated surfactants, also known as fluorosurfactants. Fluorosurfactants that can provide stable emulsions include triperfluoroalkylcholate; perfluoroalkylcholestanol; perfluoroalkyloxymethylcholate; C 3 F 7 O(CF 2 ) 3 C(═O)NH(CH 2 ) 3 N(O)(CH 3 ) 2 (XMO-10); and fluorinated polyhydroxylated surfactants, such as, for example, those discussed in “Design, Synthesis and Evaluation of Fluorocarbons and Surfactants for In Vivo Applications New Perfluoroalkylated Polyhydroxylated Surfactants” by J. G. Riess, et al. J. G. Riess et al.; Biomat. Artif. Cells Artif. Organs 16: 421-430 (1988).
[0068] The nonionic surfactants suitable for use in the present invention include polyoxyethylene-polyoxypropylene copolymers. An example of such class of compounds is Pluronic, such as Pluronic F-68. Anionic surfactants, particularly fatty acids (or their salts) having 12 to 24 carbon atoms, may also be used. One example of a suitable anionic surfactant is oleic acid, or its salt, sodium oleate.
[0069] It will be appreciated that choice of a particular emulsifying agent is not central to the present invention. Indeed, virtually any emulsifying agent (including those still to be developed) capable of facilitating formation of a fluorocarbon-in-water emulsion can form improved emulsions when used in the present invention. The optimum emulsifying agent or combination of emulsifying agents for a given application may be determined through empirical studies that do not require undue experimentation. Consequently, one practicing the art of the present invention should choose the emulsifying agent or combination of emulsifying agents for such properties as biocompatibility.
[0070] B. The Continuous Phase
[0071] The continuous phase comprises an aqueous medium. Preferably, the medium is physiologically acceptable. For instance, a preferred emulsion will have the ability to buffer and maintain pH, as well as provide an appropriate osmolarity. This typically has been achieved in the art through the inclusion in the aqueous phase of one or more conventional buffering and/or osmotic agents, or an agent that combines these properties.
[0072] Additionally, one may supplement the continuous phase with other agents or adjuvants for stabilizing or otherwise increasing the beneficial aspects of the emulsion. These agents or adjuvants include: steroid hormones, cholesterol, tocopherols, and/or mixtures or combinations thereof. Suitable steroid hormones include fluorinated corticosteroids.
[0073] C. Preparation of the Emulsion
[0074] Fluorocarbon emulsions according to the invention are prepared by means of conventional emulsification procedures, such as, for example, mechanical or ultrasonic emulsification of an emulsion formulation in a Manton-Gaulin mixer or Microfluidizer (Microfluidics Corp., Newton, Mass.) as described in Example 1.
[0075] The first and second fluorocarbons are combined with the aqueous phase in the desired ratios, together with the surfactant. Usually, a preemulsion mixture is prepared by simple mixing or blending of the various components. This preemulsion is then emulsified in the desired emulsification apparatus.
[0076] The second fluorocarbon can comprise from about 0.1% to 50% (w/w) of the total amount of fluorocarbon; in preferred embodiments, the second fluorocarbon comprises from about 0.5% to about 40% of the total amount of fluorocarbon, with the first fluorocarbon comprising the remainder of the total fluorocarbon. The combined fluorocarbon concentration in the emulsion is preferably anywhere within the range of about 20% to about 125% (w/v). In preferred emulsions, the total perfluorocarbon concentration is from about 30%, 40%, or 50% to about 70%, 80%, 90%, or 100% (w/v). Emulsifiers are added in concentrations of from about 0.1% to 10%, more preferably 1% or 2% to about 6% (w/v).
[0077] Effect of Stabilizer on Emulsion Particle Size
[0078] The addition of stabilizing second fluorocarbons such as perfluorodecyl bromide to 90% perfluorocarbon emulsion comprising perfluorooctyl bromide provides substantial decreases in the range of particle size and improves particle size stability (Example 3, Table 1). The data in FIG. 1 representing average particle growth size in 90% w/v perfluorocarbon emulsions containing 1% and 10% perfluorodecyl bromide (PFDB) indicate that the stabilizing effect of PFDB on particle size can be observed in emulsion comprising only 1% w/w PFDB, and that substantial improvement occurs at the 10% w/w concentration level. The data of FIG. 2 indicate that PFDB at an intermediate concentration of 4.5% w/v (equivalent to 5% w/w of total perfluorocarbon) also maintains a narrower distribution of particle sizes in a 90% w/v perfluorocarbon emulsion after 3 months of aging as compared to a non-stabilized emulsion. Perflubron emulsions stabilized with PFDB also have smaller initial particle sizes (Tables I and II, FIG. 2).
[0079] The stabilizing effect of PFDB in perfluorocarbon emulsion is also independent of total fluorocarbon concentration (Table II, FIG. 3). Emulsions comprising 60% w/v or 90% w/v perfluorocarbon, consisting of 10% w/w PFDB and 90% w/w perflubron, demonstrated similar initial average particle sizes and particle size stability on aging. The stabilizing effect of PFDB also operates in perfluorodecalin emulsions (Example 6, Table III), to produce emulsions having a small initial particle size and to substantially retain that size during three months of aging at 40 EC.
[0080] The stabilizing effect of PFDB operates in both perflubron and perfluorodecalin emulsions (Example 7) comprising either 60% or 90% (Table IV) to produce emulsions having a small initial average particle size and to retain that size and substantially retaining that size during 3 months of aging at 40EC.
[0081] Further details of the method of the present invention can be more completely understood by reference to the following illustrative Examples.
EXAMPLE 1
[0082] Preparation of Reference Emulsion
[0083] Composition of Reference Emulsion:
[0084] Perflubron/Lecithin (90/4% w/v)
[0085] A reference emulsion containing 90 g PFOB, 4 g egg yolk phospholipid (EYP), and physiological levels of salts and buffers was prepared by high pressure homogenization according to the method of Long (U.S. Pat. No. 4,987,154).
EXAMPLE 2
[0086] Stabilization of a 90% w/v Fluorocarbon Emulsion (Perfluorooctyl Bromide/Perfluorodecyl Bromide)
[0087] The protocol of Example 1 was repeated to form four additional emulsions, except that in successive emulsions, the fluorocarbon was perfluorooctyl bromide containing 1%, 2%, 5%, and 10% perfluorodecyl bromide (w/w), respectively.
EXAMPLE 3
[0088] Emulsion Stability
[0089] The emulsions prepared by the procedures of Examples 1 and 2 were placed on accelerated stability testing at 40EC for three months. Table I demonstrates particle size stability over time for 90% (w/v) fluorocarbon emulsions. Such emulsions include a control, in which 100% of the fluorocarbon phase is perfluorooctyl bromide, and emulsions of the present invention in which the fluorocarbon phase is 99% to 90% w/w perfluorooctyl bromide, with from 1% to 10% w/w of perfluorodecyl bromide added as a stabilizer. In FIG. 1 and Table I, “EYP” is egg yolk phospholipid, “perflubron” is perfluorooctyl bromide, “PFDB” is perfluorodecyl bromide, and “S” is the rate of particle growth in units of μm 3 /mo. FIG. 1 illustrates typical Lifshitz-Slezov graphs of d 3 as a function of time for these emulsions. The cubed term is chosen for the ordinate since Lifshits-Slezov theory predicts that plots of d 3 vs time will yield a straight line. In fact, this linear dependence is generally observed for fluorocarbon emulsions.
TABLE I Stabilizing Effect of Perfluorodecyl bromide (90% w/v Emulsion Containing Perflubron/Perfluorodecyl bromide (PFDB) with 4% EYP, T = 40EC) Size Size Size Initial After After After PFDB Size One Two Three % w/w (μm) Month Months Months S × 1000 0% 0.23 0.39 0.49 0.52 44.4 (0.13) (0.19) (0.20) (0.23) 1% 0.23 0.29 0.37 0.37 14.2 (0.12) (0.16) (0.19) (0.18) 2% 0.19 0.23 0.26 0.32 8.3 (0.09) (0.12) (0.14) (0.17) 5% 0.18 0.20 0.24 0.28 5.4 (0.08) (0.10) (0.13) (0.14) 10% 0.20 0.25 0.27 0.27 3.9 (0.12) (0.13) (0.14) (0.16)
EXAMPLE 4
[0090] Stabilization of a 60% w/v Fluorocarbon Emulsion (Perfluoroctyl Bromide/Perfluorodecyl Bromide)
[0091] Table II compares particle size increase in a 60% w/v perflubron emulsion containing perfluorodecyl bromide with a particle size increase in a reference emulsion that does not contain PFDB.
TABLE II Stabilization of a 60% w/v Fluorocarbon Emulsion (Perfluoroctyl Bromide/Perfluorodecyl Bromide) Size Initial after 1 Size after 2 Size after 3 Size month months months S × 1000 Sample (μm) (40EC) (40EC) (40EC) (μm 3 /mo) 0% w/v 0.20 0.34 0.38 0.39 16.9 PFDB 10% w/v 0.18 0.20 0.23 0.23 2.3 PFDB
EXAMPLE 5
[0092] In Vivo Data
[0093] [0093]FIG. 4 graphs the % lethality in mice injected with various doses of a 90% w/v fluorocarbon containing 90% w/w perfluorooctyl bromide and 10% w/w perfluorodecyl bromide, along with 3% w/v EYP. The LD50 was approximately 48 ml/kg. FIG. 9 graphs the LD 50 in mice of a 90% w/v perfluorocarbon emulsion of the present invention, consisting of 90% w/w Perflubron, as the first fluorocarbon, and 10% perfluorodecyl bromide, as the second fluorocarbon, emulsified with 3% w/v egg yolk phospholipid. The LD 50 was approximately 48 ml/kg.
EXAMPLE 6
[0094] Stability of Perfluorodecalin/Perfluorodecyl bromide Emulsions
[0095] Concentrated perfluorodecalin emulsions were prepared according to the procedure of Examples 1 and 2 are studied for stability as described in Example 3. Stability data is presented in Table III.
TABLE III Stabilizing Effect of Perfluorodecyl Bromide on Concentrated Perfluorodecalin Emulsions Size Size Size Initial after 1 after 2 after 3 Size month months months S × 1000 Sample (μm) (40EC) (40EC) (40EC) (μm 3 /mo) 58.2% w/v FDC 0.17 0.33 0.40 0.49 36.6 4.6% w/v EYP 58.2% w/v FDC 0.18 0.19 0.22 0.25 3.3 10% w/v PFDB 4.6% EYP 81% w/v FDC 0.24 0.34 0.45 0.57 56.6 3% w/v EYP 81% w/v FDC 0.19 0.22 0.25 0.27 4.3 9% w/v PFDB 3% EYP
EXAMPLE 7
[0096] Predicted Organ Retention Times
[0097] Table IV compares physical data (including organ retention times of stabilizing fluorocarbons suggested in the prior art with comparable data for compounds of the present invention. Note that, although the molecular weight and boiling point of F-decylbromide are comparable to the prior art, the critical solution temperature (which is related to organ retention time) is dramatically lower.
[0098] [0098]FIG. 5 illustrates the critical solution temperatures of several fluorocarbons as a function of molecular weight. Note that the prior art stabilizers of Davis, et al., Meinert, Perftoran, and Green Cross (F-tripropylamine), and 50 other assorted fluorocarbons all exhibit a predictable relationship between CST and molecular weight.
[0099] On the other hand, the lipophilic stabilizers of the present invention have substantially lower CSTs, and therefore substantially shorter organ retention half lives.
TABLE IV Physical Properties of Minor Components Discussed in Literature (Proposed Minor Components are listed in Boldface) Name Formula (days) t 1/2 MW(g/mol) b.p.(C) CSTH(C) Davis, et al. (U.S. Pat. No. 4,859,363) F-perhydrofluorene C 13 F 22 574 192-193 n.a. F-perhydrophenanthrene C 14 F 24 624 215-216 48 F-perhydrofluoranthene C 16 F 26 686 242-243 n .a. Kabalnov, et al. (Kolloidin Zh. 4827-32(1986)) F-N-methylcyclohexylpiperidine C 12 F 21 N 557 n.a. 40 Meinert (U.S. Pat. No. 5,120,731) F-N-cyclohexylmorpholine C 10 F 18 NO 492 n.a. 31 F-dimorpholinoethane C 10 F 20 N 2 O 2 560 164 38 F-dimorpholinopropane C 11 F 22 N 2 O 2 610 182 45 F-dimorpholinopentane C 13 F 26 N 2 O 2 710 215 60 F-dipiperidine C 10 F 16 N 2 452 145-150 36 F-dipiperidinomethane C 11 F 18 N 2 502 165-175 42 F-dipiperidinoethane C 12 F 20 N 2 552 181-186 49 F-dipiperidinopropane C 13 F 22 N 2 602 195-203 56 F-dipiperidinobutane C 14 F 24 N 2 652 231-238 72 Present Study F-decalin C 10 F 18 462 142 22 F-hexyl bromide C 6 F 13 Br 399 n.a. n.a. F-octyl bromide C 8 F 17 Br 499 143 (−19) a F-decyl bromide C 10 F 21 Br 599 (198) b (19) a F-bromopolyether C 11 F 23 O 3 Br 697 n.a. 32
EXAMPLE 8
[0100] Organ Retention Time vs. Fluorocarbon Molecular Weight
[0101] [0101]FIG. 6 presents data for organ retention times vs. molecular weight for a number of fluorocarbons. The fluorocarbons of Meinert, Kabalnov, and Davis are all contained within the large group, which show a tight correlation between organ retention time and fluorocarbon molecular weight. Based on this the optimal molecular weight for blood substitute applications has been defined to be 460-550 g/mol. The lower limit is defined by fluorocarbons with vapor pressures greater than 20 torr which causes gas emboli, while the upper limit is defined by fluorocarbons with organ retention times of less than 3 weeks. It is clear from FIG. 6 that the lipophilic fluorocarbons PFOB, PFDB, and PPEB (perfluoropolyether bromide, C 11 F 23 O 3 Br) have organ retention times less than be predicted from the molecular weight. Due to their decreased water solubilities (which follows with molecular weight) PFDB and PPEB are expected to stabilize fluorocarbon emulsions by decreasing Ostwald ripening.
EXAMPLE 9
[0102] Measurement of Critical Solution Temperature (CST)
[0103] Critical solution temperature for fluorocarbon liquids was measured in the following manner: Equivolume mixtures of the test fluorocarbon and hydrocarbon (e.g., hexane) are placed in a sealed vial and submerged in a temperature controlled water bath. Samples are cooled until two distinct phases are present. At this point, the temperature is increased slowly. The lowest temperature at which the two phases are completely miscible (i.e., a single liquid phase) is defined as the CST.
[0104] For comparison purposes, all CST temperatures used in this patent are reported versus hexane. It is often not possible, however, to measure the CST for lipophilic fluorocarbons versus hexane, since the CSTs for these substances are very low. Thus, the CST for lipophilic substances is often measured in longer chain length hydrocarbons, and the value versus hexane is determined via extrapolation of linear plots of CST vs. alkane chain length.
[0105] Although the present invention has been disclosed in the context of certain preferred embodiments, it is intended that the scope of the invention be measured by the claims that follow, and not be limited to those preferred embodiments:
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Storage stable fluorocarbon emulsions having a continuous aqueous phase and a discontinuous fluorocarbon phase, in which the fluorocarbon phase comprises a major amount of a first fluorocarbon or fluorocarbon mixture, and a minor amount of a second fluorocarbon or fluorocarbon mixture, in which the second fluorocarbon has a molecular weight greater than that of the first fluorocarbon and the second fluorocarbon includes a lipophilic moiety in its structure, whereby the second fluorocarbon serves to promote particle size stability in the emulsion while simultaneously providing favorably short organ retention times when administered to animals in vivo.
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The present invention relates generally to apparatus and methods for facilitating wound healing through the use of electrical stimulation, and more particularly to apparatus and methods for providing a voltage gradient and a pattern of current flow that envelopes and permeates the wound.
BACKGROUND OF THE INVENTION
Connective tissue wound healing typically occurs in three distinct phases. Although these phases intertwine and overlap, each has a specific sequence of events that distinguishes it. During the initial, or inflammatory phase, the body begins to clean away bacteria and initiate hemostasis. The inflammatory phase has three subphases: hemostasis; leukocyte and macrophage migration; and epithelialization. This phase typically lasts for about four days.
The second phase, the proliferative phase, is characterized by a proliferation of fibroblasts, collagen synthesis, granulation, and wound contraction. The proliferative phase typically begins about 48 hours after the wound is inflicted and can extend anywhere from two hours up to a week. In this phase, the fibroblast cells begin the synthesis and deposition of the protein collagen, which will form the main structural matrix for the successful healing of the wound.
In the third phase, the remodeling phase, the collagen production slows. The collagen that is formed in this stage is more highly organized than the collagen formed in the proliferative phase. Eventually, the remodeled collagen increases the tensile strength in the wound and returns the wound to about 80% of the skin's original strength.
This is the general process that occurs in healthy human beings. Patients that suffer from conditions which limit the flow of blood to the wound site are unfortunately not able to exhibit the normal wound healing process as described. In some patients this process can be halted. Factors that can negatively affect this normal wound healing process include diabetes, impaired circulation, infection, malnutrition, medication, and reduced mobility. Other factors such as traumatic injuries and burns can also impair the natural wound healing process.
Poor circulation, for varying reasons, is the primary cause of chronic wounds such as venous stasis ulcers, diabetic ulcers, and decubitus foot ulcers. Venous stasis ulcers typically form just above the patient's ankles. The blood flow in this region of the legs in elderly or incapacitated patients can be very sluggish, leading to drying skin cells. These skin cells are thus oxygen starved and poisoned by their own waste products and begin to die. As they do so, they leave behind an open leg wound with an extremely poor chance of healing on its own. Diabetic foot ulcers form below the ankle, in regions of the foot that have very low levels of circulation.
Similarly, decubitus ulcers form when skin is subjected to constant compressive force without movement to allow for blood flow. The lack of blood flow leads to the same degenerative process as described above. Paraplegics and severely immobile elderly patients which lack the ability to toss and turn while in bed are the main candidates for this problem.
Traditional approaches to the care and management of these types of chronic non-healing wounds have included passive techniques that attempt to increase the rate of repair and decrease the rate of tissue destruction. Examples of these techniques include antibiotics, protective wound dressings, removal of mechanical stresses from the affected areas, and the use of various debridement techniques or agents to remove wound exudate and necrotic tissue.
For the most part, these treatment approaches are not very successful. The ulcers can take many months to heal and in some cases they may never heal or they may partially heal only to recur at some later time.
Active approaches have been employed to decrease the healing time and increase the healing rates of these ulcers. These approaches may include surgical treatment as well as alterations to the wound environment. These alterations may include the application of a skin substitute impregnated with specific growth factors or other agents, the use of hyperbaric oxygen treatments, or the use of electrical stimulation. It has also been shown experimentally (both in animal and clinical trials) that specific types of electrical stimulation will alter the wound environment in a positive way so that the normal wound healing process can occur or in some cases occur in an accelerated fashion.
Therapeutic Electrostimulation
The relationship between direct current electricity and cellular mitosis and cellular growth has become better understood during the latter half of the twentieth century. Weiss, in Weiss, Daryl S., et. al., Electrical Stimulation and Wound Healing, Arch Dermatology, 126:222 (February 1990), points out that living tissues naturally possess direct current electropotentials that regulate, at least in part, the wound healing process. Following tissue damage, a current of injury is generated that is thought to trigger biological repair. This current of injury has been extensively documented in scientific studies. It is believed that this current of injury is instrumental in ensuring that the necessary cells are drawn to the wound location at the appropriate times during the various stages of wound healing. Localized exposure to low levels of electrical current that mimic this naturally occurring current of injury has been shown to enhance the healing of soft tissue wounds in both human subjects and animals. It is thought that these externally applied fields enhance, augment, or take the place of the naturally occurring biological field in the wound environment, thus fostering the wound healing process.
Weiss continues to explain, in a summary of the scientific literature, that intractable ulcers have demonstrated accelerated healing and skin wounds have resurfaced faster and with better tensile properties following exposure to electrical currents. Dayton and Palladino, in Dayton, Paul D., and Palladino, Steven J., Electrical Stimulation of Cutaneous Ulcerations—A Literature Review, Journal of the American Podiatric Medical Association, 79(7):318 (July 1989), also state that the alteration of cellular activity with externally applied currents can positively or negatively influence the status of a healing tissue, thereby directing the healing process to a desired outcome.
Furthermore, research conducted by Rafael Andino during his graduate tenure at the University of Alabama at Birmingham, also demonstrated that the presence of electrical fields (in this case induced by the application of pulsating electromagnetic fields) dramatically accelerated the healing rates of wounds created in an animal model. This research found that the onset and duration of the first two phases of the wound healing process, the inflammatory and proliferative phases, had been markedly accelerated in the treated wounds while the volume of collagen which had been synthesized by the fibroblasts was also markedly increased in the treated wounds. This resulted in the wounds healing in a much shorter amount of time. Similar findings from other researchers can be found in other wound healing literature.
U.S. Pat. No. 5,433,735 to Zanakis et al. and U.S. Pat. No. 4,982,742 to Claude describe various electro-stimulation apparatus and techniques for facilitating the regeneration and repair of damaged tissue. However, each of these references suffers from the disadvantage that the pattern of current flow generated with these electrode devices does not pass through all portions of the wound and thus, certain portions of the wound site may not be exposed to the beneficial effects of electrostimulation.
U.S. Pat. No. 4,911,688 to Jones describes a wound cover that includes a chamber that encloses fluid around the wound. One electrode is located in the chamber and another electrode is placed away from the wound on the skin. By using conductive liquid within the chamber, a circuit is completed allowing current to flow from the electrode in the chamber, through the liquid, wound, and surrounding tissue and skin to the other electrode. The liquid is introduced into the chamber and replaced using two ports, one port is used to introduce the liquid while at the same time the other port is used to remove the gas (when the wound cover is originally applied to the wound) or fluid within the chamber. This wound cover, however, is complicated to use and involves a delicate process of adding and replacing the conductive liquid.
In view of the foregoing, it is an object of the present invention to provide improved apparatus and methods for easily providing a voltage gradient and a pattern of current flow that envelops and permeates the entire wound site.
SUMMARY OF THE INVENTION
This and other objects of the invention are accomplished in accordance with the principles of the present invention by providing an electrode system that includes two electrodes that are adapted for connection to a power source sufficient to cause a current to flow between them. The electrodes are shaped and oriented to cause a pattern of current flow that envelops and permeates the entire wound site. Such shapes and orientations may include a circular first electrode located at and covering the wound site and a second electrode shaped as a ring fully encircling the first electrode. The second electrode may be located outside or partially within the wound site. Other suitable shapes of the electrodes may include electrodes that are ovally shaped, rectangularly shaped, triangularly shaped or any other suitable shape where one electrode encircles the other electrode. The shape of the electrode may conform to the shape of the wound.
The two electrodes of the electrode system may be mounted to an oxygen-permeable top layer that is impermeable to water and water vapor. The top layer may provide support for the electrodes and may allow the wound site to breathe.
The electrode system may also include an electrically insulative element that is disposed between the two electrodes. The insulative element may ensure that most if not all of the current flow between the electrodes passes through the damaged and healthy surrounding tissue.
The power supply for applying a voltage potential across the electrodes may be local to or remote from the electrode system. In one suitable arrangement, the power supply is attached to the top layer of the electrode system. The power supply can be configured to provide a constant or varying voltage, a constant or varying current, or any other suitable electrical output to the electrodes to facilitate wound healing. For example, the power supply may be configured to provide the desired current or voltage to the electrodes at different time intervals with the same electrode system in place. In one suitable embodiment, the power supply is a battery. In another suitable embodiment, the power supply is electronic circuitry that is configured to provide the desired current or voltage.
In another suitable embodiment of the invention, the two electrodes of the electrode system are comprised of oppositely charged polymers of sufficient voltage differential and charge capacity to cause a current to flow from the first electrode to the second electrode through the wound.
The electrode system can be designed and fabricated to be either disposable or reusable.
The electrode system according to the various embodiments described herein is capable of generating a voltage gradient and a pattern of current flow that envelops and permeates the entire wound site. Such a pattern of current flow maximizes the recruitment of the necessary cells to the wound location at the appropriate times during the various stages of wound healing.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and advantages of the invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:
FIG. 1 is a cross-sectional view of an illustrative electrode system in accordance with the present invention taken generally along the line 1 — 1 of FIG. 2 .
FIG. 2 is a cross-sectional view of the electrode system of FIG. 1 taken generally along the line 2 — 2 of FIG. 1
FIG. 3 is a cross-sectional view of the electrode system of FIG. 1 as applied to a wound that illustrates the pattern of current flow generated by the electrode system in accordance the present invention.
FIG. 4 is a perspective view of an illustrative electrode system placed over a wound site in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a cross-sectional view of electrode system 10 . The view in FIG. 1 is taken along the line 1 — 1 of FIG. 2 . FIG. 2 shows a simplified cross-sectional view of electrode system 10 taken alone the line 2 — 2 of FIG. 1 . As illustrated in FIG. 1, electrode system 10 includes top overlay layer 20 to which electrodes 22 and 24 , electrically insulative element 26 , and end material 28 are attached. Electrode 22 is located towards the center of top overlay layer 20 . Electrically insulative element 26 surrounds electrode 22 and electrode 24 surrounds electrically insulative element 26 . Attached to the other side of electrodes 22 and 24 , electrically insulative element 26 , and end material 28 are adhesive layers 52 and 54 . As illustrated in FIG. 2, electrically conductive lead 32 connects electrode 22 to terminal 42 of power supply 40 and electrically conductive lead 34 connects electrode 24 to terminal 44 of the power supply 40 .
Top overlay layer 20 may serve several different purposes. First, top overlay layer 20 provides the mechanical integrity of electrode system 10 , thus providing structural support for electrodes 22 and 24 . Second, top overlay layer 20 should be flexible enough to allow electrode system 10 to conform to the contours of the skin surface to which it is adhered. Third, top overlay layer 20 should be oxygen permeable to allow the wound site to breathe. Finally, top overlay layer 20 should be water impermeable so that the wound site remains moist. In some embodiments, all of these characteristics may not be necessary. For example, a separate water impermeable layer may be used to keep the wound site moist. Top overlay layer 20 may be comprised of any suitable material or structure that exhibits these characteristics. For example, top overlay layer 20 may be comprised of a mesh structure of polypropylene, polyethylene, polyurethane, polytetrafluoroethylene (PTFE), or any other suitable material. In one embodiment, top overlay layer 20 can be electrically insulative to prevent current from flowing between electrodes 22 and 24 , which are attached to top overlay layer 20 . In another suitable embodiment, the adhesive or binding agent (not shown) used to adhere electrodes 22 and 24 to top overlay layer 20 can be electrically insulative to prevent current from flowing between electrodes 22 and 24 .
Electrodes 22 and 24 may be thin metal, metallic paint or pigment deposition, metallic foil, conductive hydrogels, or any other suitable conductive material. Hydrogels are generally clear, viscous gels that protect the wound from dessicating. In one suitable approach, conductive hydrogels may be used as the material for electrodes 22 and 24 because of their permeability to oxygen and ability to retain water. Both oxygen and a humid environment is required for the cells in a wound to be viable. In addition, hydrogels can be easily cast into any shape and size. Various types of conductive hydrogels may be employed, including cellulose, gelatin, polyacrylamide, polymethacrylamide, poly(ethylene-co-vinyl acetate), poly(N-vinyl pyrrolidone), poly(vinyl alcohol), HEMA, HEEMA, HDEEMA, MEMA, MEEMA, MDEEMA, EGDMA, mathacrylic acid based materials, and siliconized hydrogels. PVA-based hydrogels are inexpensive and easy to form. The conductivity of such hydrogels can be changed by varying the salt concentration within the hydrogels. By increasing the salt concentration within a hydrogel, the conductivity of the hydrogel increases.
Insulative element 26 prevents the flow of current between electrodes 22 and 24 above the wound surface such as by moisture trapped under the top overlay layer. Insulative element 26 may be composed of any high resistance material such as polythylene, poly(tetrafluoroethylene) (TEFLON), polyurethane, polyester, a hydrogel made to be an insulator or any other suitable insulative material. In addition, insulative element 26 may be formed of a material or designed to have gaps or openings within its body to prevent the flow of current or greatly increase the current resistance above the wound surface.
End material 28 surrounds electrode 24 . End material 28 , in combination with the outer edge of top overlay layer 20 , forms the outer edge of electrode system 10 . End material 28 may be comprised of any suitable material flexible enough to allow electrode system 10 to conform to the contours of the skin surface to which it is adhered. In one embodiment, end material 28 may be composed of the same material as top overlay layer 20 . In one suitable approach, end material 28 may be a part of and seamless with top overlay layer 20 .
Conductive adhesive layers 52 and 54 are attached to the underside of electrode system 10 , contacting electrodes 22 and 24 , respectively and electrically insulative element 26 . Adhesive layers 52 and 54 should be separated from each other by a suitable space or gap 58 to prevent short-circuiting of the electrodes. Adhesive layers 52 and 54 may be a hydrogel, fibrin, conductively transformed cyanoacrylates or can be comprised of any suitable electrically conductive material capable of attaching electrode system 10 to the skin and wound surfaces. Adhesive layer 52 can be arranged to distribute substantially the same voltage of electrode 22 to the entire surface of the wound. Similarly, adhesive layer 54 can be arranged to distribute substantially the same voltage of electrode 24 to the skin surrounding the wound. In another suitable approach, adhesive layer 52 can be arranged so that the center of adhesive layer 52 applies a voltage substantially similar to electrode 22 to the center of the wound and that the outer edge of adhesive layer 52 applies a voltage that is between the voltages of electrodes 52 and 54 to the outer edge of the wound. The voltage applied to the wound may be varied, for example, by varying the thickness of adhesive 52 or by any other suitable method.
As illustrated in FIG. 1, adhesive layer 52 extends beyond electrode 22 . In another suitable arrangement, adhesive layer 52 may be the same size as or smaller than electrode 22 . Adhesive layer 54 as illustrated is larger than electrode 24 . In another suitable arrangement, adhesive layer 54 may be the same size as or smaller than electrode 24 .
In another suitable embodiment, conductive adhesive layers 52 and 54 may be omitted from electrode system 10 . In this embodiment, electrodes 22 and 24 are themselves adhesive and capable of attaching electrode system 10 to the wound site. Conductive hydrogels can be fashioned to have the requisite adhesive properties, thereby eliminating the need for separate adhesive layers. One type of highly conductive hydrogel that is sufficiently tacky and adhesive to adhere to the skin is described in U.S. Pat. No. 4,989,607 to Keusch et al. Electrodes 22 and 24 may be comprised of any suitable conductive adhesive material capable of attaching electrode system 10 to the wound site.
Backing layer 60 is attached to conductive adhesives 52 and 54 to protect the adhesive layer prior to the use of electrode system 10 . Backing layer 60 may be peeled off of adhesives 52 and 54 to expose the adhesive layer prior to contacting electrode system 10 to the wound site. Backing layer 60 may protrude out from underneath top overlay layer 20 in one area, such as area 60 ′ as shown in FIG. 2, to allow the user to easily remove backing layer 60 from electrode system 10 .
In use, electrode system 10 is positioned over the wound site such that electrode 22 is located at approximate the center of the wound site and adhesive layer 52 can be sized to cover the entire wound. Electrode system 10 is provided in a family of sizes appropriate for wounds of various sizes. Electrode 24 and adhesive layer 54 are generally in the shape of a ring and are located a distance away from electrode 22 . In one arrangement, the diameters of the inner edges of electrode 24 and adhesive layer 54 are greater than the diameter of the wound. In another words, the size of the wound determines the minimum inner diameter of electrode 24 and adhesive layer 54 . In another suitable arrangement, adhesive layer 52 can be sized to cover the inner portion of the wound and the inner diameters of the inner edges of electrode 24 and adhesive layer 54 may be the same or less than the size of the wound.
FIG. 3 is a cross-sectional view of electrode system 10 as applied to wound 60 . As shown in FIG. 3, the pattern of current flow generated by electrode system 10 is toroidal in shape. A toroid is generally formed by rotating a circular disk about an axis, where the axis lies in the plane of the disk, but outside of the disk. Here, the pattern of current flow is similar to a semicircle rotated about an axis, where the axis lies in the plane of the semicircle and the axis is near the edge of the semicircle. The current generally flows tangential to the radial lines of the semicircle. Because electrode 24 surrounds electrode 22 , the pattern of current flow is similar to the semicircular disk rotated completely around the axis. Therefore, the pattern of current flow is toroidal in shape. The pattern of current flow as illustrated in FIG. 3 would therefore generally be the same regardless of the angle of the cross-section cut through electrode system 10 with respect to reference direction 65 of FIG. 2 . More specifically, as illustrated, electrode 22 is negatively charged and electrode 24 is positively charged. The lines of current flow extend from adhesive 54 through wound 60 to adhesive 52 in an arcuate shape. The lines of current pass through the entire wound 60 , thereby enveloping and permeating the entire wound and the adjoining unwounded tissue. If the voltage that is applied to the wound from adhesive 52 is varied, as described above, then the current density at different portions of wound 60 can be increased or decreased accordingly. Electrode system 10 can produce a current density within the wound that is generally between 1 μA/cm 2 and 10,000 μA/cm 2 . Depending on the size and nature of the wound, electrode system 10 may be configured to produce a current density within the wound that is less than of 1 μA/cm 2 or greater 10,000 μA/cm 2 .
Referring to FIG. 2, conductive leads 32 and 34 , which connect electrodes 22 and 24 respectively to power supply 40 , may be comprised of metal, conductive ink or any other suitable conductive material. In one suitable arrangement, leads 32 and 34 are comprised of conductive carbon ink that is screened onto top overlay layer 20 . In such an arrangement, electrodes 22 and 24 are formed in place over conductive leads 32 and 34 , respectively.
Power supply 40 generates a voltage that is applied to electrodes 22 and 24 through leads 32 and 34 , respectively. Power supply 40 may be configured to apply a voltage that is anywhere between 1 mV and 9 V. The resulting current flow that flows through the wound may be between 1 μA and 50 mA. Depending on the size and nature of the wound, power supply 40 may be configured to apply a voltage that is less than 1 mV or greater than 9 V. The resulting current flow may therefore be less than 1 μA or greater than 50 mA. Power supply 40 may be attached to the upper portion of top overlay layer 20 or any other suitable location on electrode system 10 or may be located remote from electrode system 10 . In one suitable embodiment, power supply 40 is a battery. Power supply 40 may be any suitable battery such as an alkaline, nickel cadmium, or lithium battery. In one suitable arrangement, power supply 40 is a lithium polymer stack. The battery may be arranged so that terminal 42 is negative and terminal 44 is positive. Thus, electrode 22 functions as an anode and electrode 24 functions as a cathode. As described above, current will flow along outward radial lines from electrode 24 through the wound to electrode 22 . In another suitable approach, the battery can be arranged so that terminal 42 is positive and terminal 44 in negative. In such an approach, the lines of current are reversed and directed outward from electrode 22 to electrode 24 .
In another suitable embodiment, power supply 40 is comprised of electronic circuitry that is configured to provide a constant or varying voltage, a constant or varying current, or any other suitable electrical output. The current density within the wound site may therefore be constant or time varying. When power supply 40 varies the voltage or current, electrodes 22 and 24 may change polarities at a constant or at a time varying frequency. In another suitable electrical output, power supply 40 can be configured to pulse electrodes 22 and 24 to provide other possible therapeutic benefits.
In one suitable arrangement, the electrical circuitry can be configured to provide a constant current source using a current-to-voltage converter. The current to voltage converter may be probed at test points to check the current accuracy. The constant current source may be implemented with an operational amplifier (Op-amp). The Op-amp compares a precision voltage reference source to the output of a current-to-voltage converter and adjusts the output current until the reference and the converter are equal. The output voltage is limited to the battery voltage minus a certain predetermined amount used for operational purposes.
The circuit may be built with surface mount integrated circuits and other surface mount components and may be powered, for example, by lithium coin cell batteries.
The electrode system 10 herein described may not require a switch to be activated for current to commence flowing between electrodes 22 and 24 . Rather, current may begin to flow following conductive contact of electrodes 22 and 24 to the wound site. Such contact completes a circuit between the electrodes and results in current flow between the electrodes. In another suitable embodiment, a switch may be located on electrode system 10 that may allow the user to engage and disengage power supply 40 to electrodes 22 and 24 .
Electrode system 10 may contain within its circuitry a visual indicator to allow the user to determine whether or how well the electrode system is functioning. The visual indicator may be a light emitting diode (LED), a series of LEDs, a basic current meter, or any other suitable visual indicator.
FIG. 4 demonstrates a view of electrode system 10 placed over wound 60 . In this embodiment, electrode system 10 is a disposable, one-time-use bandage that uses a battery and associated circuitry as power supply 40 , which is attached to electrode system 10 . Appropriate electrical parameters may be selected such that the current generated by the internal circuitry will last for a desired period of time. For example, the desired period of time may be at least as long as the typical amount of time a normal bandage is used on the wound. For users with chronic ulcers, this amount of time may typically be 1 to 2 days. Therefore, after electrode system 10 is activated by placement over the wound, an electrical current may last for 1 to 2 days. When it is time for electrode system 10 to be replaced, a new electrode system will be applied and the treatment will continue as required by the individual user and the type of wound present.
While electrode system 10 has been described as being generally circular in shape, it is understood that electrode system 10 may also be provided in other shapes as well. For example, electrode system 10 may be provided in an oval shape, rectangular shape, triangular shape, or any other suitable shape. The resulting pattern of current flow would therefore be similar to the toroidal shape described above which has been stretch from a circle to an oval shape, rectangular shape, triangular shape, or any other suitable shape of electrode system 10 . Electrode system 10 is preferably provided in different shapes appropriate for wounds of different shapes. For example, if the wound is a long gash wound, a rectangular or oval shaped electrode system may be the appropriate shape for the wound. In one suitable approach, a preferred electrode system shape for a wound is a shape that will allow adhesive 52 to cover the entire wound and that will minimize the amount of area that adhesive 52 covers exterior to the wound. This will maximize the current flow through the wound.
In another suitable electrode system embodiment, electrodes 22 and 24 are electrically charged polymers. In this embodiment, power supply 40 and leads 32 and 34 , as illustrated in FIGS. 1 and 2 are not required. In addition, top overlay layer 20 may not be required and electrodes 22 and 24 may be separately applied. Electrodes 22 and 24 can be oppositely charged polymers (e.g., hydrogel or any other suitable material for holding a charge) of sufficient differential voltage potential and of sufficient charge densities to cause a current to flow between the electrodes. In one suitable arrangement, electrode 22 is negatively charged and electrode 24 is positively charged. This would cause current to flow through the wound to negative electrode 22 from positive electrode 24 . In another suitable arrangement, electrode 22 is positively charged and electrode 24 is negatively charged. This would cause current to flow from positive electrode 22 through the wound to negative electrode 24 .
The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.
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An electrode system is provided that generates a current flow that envelops and permeates an entire wound site. The electrode system includes two electrodes that are shaped and oriented to cause the current to flow from one electrode through the wound to the other electrode. A first electrode is applied to the wound site and the second electrode encircles the first electrode and is applied to the skin surrounding the wound cite. The two electrodes may be mounted to an oxygen-permeable layer that provides support for the electrodes and allows the wound site to breathe. An electrically insulative element may be disposed between the two electrodes. A power supply, which may be local to or remote from the electrode system, is provided for applying a voltage potential across the electrodes. In another suitable embodiment, the two electrodes are comprised of oppositely charged polymers.
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This application is a division of Ser. No. 09/161,653 filed Sep. 28, 1998 now U.S. Pat. No. 6,005,102 which; claims the benefit of U.S. Provisional application Ser. No. 60/090,099, which was converted from U.S. patent application Ser. No. 08/950,818, filled Oct. 15, 1997.
This invention provides novel compounds useful in the production of biologically active compounds, as well as processes for their production. More particularly, the present invention provides novel alkoxyalkyl-dialkylamines which may be used in the production of pharmaceutical products.
BACKGROUND OF THE INVENTION
Matrix metalloproteinases (MMPs) are a group of enzymes that have been implicated in the pathological destruction of connective tissue and basement membranes [Woessner, J. F., Jr. FASEB J. 1991, 5, 2145; Birkedal-Hansen, H.; Moore, W. G. I.; Bodden, M. K.; Windsor, L. J.; Birkedal-Hansen, B.; DeCarlo, A.; Engler, J. A. Crit. Rev. Oral Biol. Med. 1993, 4, 197; Cawston, T. E. Pharmacol. Ther. 1996, 70, 163; Powell, W. C.; Matrisian, L. M. Cur. Top. Microbiol. and Immunol. 1996, 213, 1]. These zinc containing endopeptidases consist of several subsets of enzymes including collagenases, stromelysins and gelatinases. Of these classes, the gelatinases have bee shown to be the MMPs most intimately involved with the growth and spread of tumors, while the collagenases have been associated with the pathogenesis of osteoarthritis [Howell, D. S.; Pelletier, J.-P. In Arthritis and Allied Conditions; McCarthy, D. J.; Koopman, W. J., Eds.; Lea and Febiger: Philadelphia, 1993; 12th Edition Vol. 2, pp. 1723; Dean, D. D. Sem. Arthritis Rheum. 1991, 20, 2; Crawford, H. C; Matrisian, L. M. Invasion Metast. 1994-95, 14, 234; Ray, J. M.; Stetler-Stevenson, W. G. Exp. Opin. Invest. Drugs, 1996, 5, 323].
The use of hormone replacement therapy for bone loss prevention in post-menopausal women is well precedented. The normal protocol calls for estrogen supplementation using such formulations containing estrone, estriol, ethynyl estradiol or conjugated estrogens isolated from natural sources (i.e. Premarin® conjugated estrogens from Wyeth-Ayerst). In some patients, therapy may be contraindicated due to the proliferative effects unopposed estrogens (estrogens not given in combination with progestins) have on uterine tissue. This proliferation is associated with increased risk for endometrosis and/or endometrial cancer. The effects of unopposed estrogens on breast tissue is less clear, but is of some concern. The need for estrogens which can maintain the bone sparing effect while minimizing the proliferative effects in the uterus and breast is evident. Certain nonsteroidal antiestrogens have been shown to maintain bone mass in the ovariectomized rat model as well as in human clinical trials. Tamoxifen (sold as Novadex® brand tamoxifen citrate by Zeneca Pharmaceuticals, Wilmington, Del.), for example, is a useful palliative for the treatment of breast cancer and has been demonstrated to exert an estrogen agonist-like effect on the bone, in humans. However, it is also a partial agonist in the uterus and this is cause for some concern. Raloxifene, a benzthiophene antiestrogen, has been shown to stimulate uterine growth in the ovariectomized rat to a lesser extent than Tamoxifen while maintaining the ability to spare bone. A suitable review of tissue selective estrogens is seen in the article “Tissue-Selective Actions Of Estrogen Analogs”, Bone Vol. 17, No. 4, October 1995, 181S-190S.
The present invention provides novel intermediates which may be used in the production of pharmaceutical compounds for anti-estrogenic and MMP-inhibiting utilities. The use of 4-carbamoylmethoxy-methoxy-benzyl chloride compounds of tie structures:
are taught NL 6402393; 1964; and Chem. Abstr. 1965, 62, 7698.
The use of 4-(2-dialkylamino-ethoxy)benzoyl chloride compounds of the structures:
are disclosed in Sharpe, C. J. et. al. J. Med. Chem. 1972, 15, 523 and Jones, C. D. et. al. J. Med. Chem. 1984, 27, 1057. Similarly, the use of 4-(2-quinolinylmethoxy)benzyl chloride
is disclosed by Huang, F-C. et. al. J. Med. Chem. 1990, 33, 1194.
SUMMARY OF THE INVENTION
The present invention provides new compounds, as well as methods for the production thereof, which can be used in the production of pharmaceutically active compounds. The compounds of this invention can particularly be used as intermediates in the production of pharmaceutical compounds, such as low molecular weight, non-peptide inhibitors of matrix metalloproteinases (e.g. gelatinases, stromelysins and collagenases) and TNF-_ converting enzyme (TACE, tumor necrosis factor-_ converting enzyme) which are useful for the treatment of diseases in which these enzymes are implicated such as arthritis, tumor metastasis, tissue ulceration, abnormal wound healing, periodontal disease, bone disease, proteinuria, aneurysmal aortic disease, degenerative cartilage loss following traumatic joint injury, demyelinating diseases of the nervous system and HIV infection. In addition, the compounds of this invention can be used to produce compounds which behave like estrogen agonists by lowering cholesterol and preventing bone loss. Therefore, these compounds are useful for treating many maladies including osteoporosis, prostatic hypertrophy, infertility, breast cancer, endometrial hyperplasia and cancer, cardiovascular disease, contraception, Alzheimer's disease and melanoma.
The present invention includes novel compounds of formula (I):
wherein:
R 1 and R 2 are, independently, selected from H; C 1 -C 12 alkyl, preferably C 1 -C 6 alkyl; or C 1 -C 6 perfluorinated alkyl, preferably —CF 3 ;
X is a leaving group, such as halogen, —O—SO 2 —CH 3 , —O—SO 2 —CF 3 , or a moiety of the structure:
Z is selected from —NO 2 , halogen, —CH 3 or —CF 3 ;
A is selected from —O— or —S—, —SO— or —SO 2 —;
m is an integer from 0 to 3, preferably 1;
R 3 , R 4 , R 5 , and R 6 are independently selected from H, halogen, —NO 2 , alkyl (preferably C 1 -C 12 alkyl, more preferably C 1 -C 6 alkyl), alkoxy (preferably C 1 -C 12 alkoxy, more preferably C 1 -C 6 alkoxy), C 1 -C 6 perfluorinated alkyl (preferably —CF 3 ), OH or the C 1 -C 4 esters or allyl ethers thereof, —CN, —O—R 1 , —O—Ar, —S—R 1 , —S—Ar, —SO—R 1 , —SO—Ar, —SO 2 —R 1 , —SO 2 —Ar, —CO—R 1 , —CO—Ar, —CO 2 —R 1 , or —CO 2 —Ar;
Y is selected from:
a) the moiety:
wherein R 7 and R 8 are independently selected from the group of H, C 1 -C 6 alkyl, or phenyl.
b) a five-membered saturated, unsaturated or partially unsaturated heterocycle containing up to two heteroatoms selected from the group consisting of —O—, —NH—, —N(C 1 C 4 alkyl)—, —N═, and —S(O) n− , wherein n is an integer of from 0-2, optionally substituted with 1-3 substituents independently selected from the group consisting of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 R 1 , —NHCOR 1 , —NO 2 ;
c) a six-membered saturated, unsaturated or partially unsaturated heterocycle containing up to two heteroatoms selected from the group consisting of —O—, —NH—, —N(C 1 C 4 alkyl)—, —N═, and —S(O) n− , wherein n is an integer of from 0-2, optionally substituted with 1-3 substituents independently selected from the group consisting of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 R 1 , —NHCOR 1 , —NO 2 ;
d) a seven-membered saturated, unsaturated or partially unsaturated heterocycle containing up to two heteroatoms selected from the group consisting of —O—, —NH—, —N(C 1 C 4 alkyl)—, —N═, and —S(O) n− , wherein n is an integer of from 0-2, optionally substituted with 1-3 substituents independently selected from the group consisting of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 R 1 , —NHCOR 1 , —NO 2 ; or
e) a bicyclic heterocycle containing from 6-12 carbon atoms either bridged or fused and containing up to two heteroatoms selected from the group consisting of —O—, —NH—, —N(C 1 C 4 alkyl)—, and —S(O) n− , wherein n is an integer of from 0-2, optionally substituted with 1-3 substituents independently selected from, the group consisting of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 R 1 , —NHCOR 1 , —NO 2 ;
and the pharmaceutically acceptable salts thereof.
It is understood in the generic description above and the other groups herein that, in each instance they may appear, R 1 and R 2 are independently selected from the group of substituents listed. Any R 1 listed in any structure herein need not represent the same substituent as another R 1 , nor does any R 2 have to be the same substitutent as any other R 2 , even if more than one R 1 or R 2 are found in the same structure.
In the description above, the symbol “Ar” indicates an monocyclic or polycyclic aryl or heteroaryl groups which may be optionally substituted by one or more substituents selected from halogen, C 1 -C 6 alkyl or —CF 3 . Examples of preferred aryl groups include anthracenyl, and phenanthrenyl groups, as well as the more preferred phenyl, cumenyl, mesityl, tolyl, xylyl, and naphthalenyl groups. Examples of preferred heteroaryl groups include indolizinyl, indazolyl, indazolyl, purinyl, quinozinyl, isoquinolinyl, quinolinyl, phthalozinyl, napthyridinyl, quinoxamiilyl, quinazolinyl, cinnolinyl, and pteridinyl groups, and the like, as well as the more preferred pyridyl, pyrazinyl, pyrimidinyl, pyridizinyl and indolyl groups.
The invention includes acceptable salt forms formed from the addition reaction with either inorganic or organic acids. Inorganic acids such as hydrochloric azid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, nitric acid useful as well as organic acids such as acetic acid, propionic acid, citric acid, maleic acid, malic acid, tartaric acid, phthalic acid, succinic acid, methanesulfonic acid, toluenesulfonic acid, napthalenesulfonic acid, camphorsulfonic acid, benzenesulfonic acid are useful. It is known that compounds possessing a basic nitrogen can be complexed with many different acids (both protic and not protic) and usually it is preferred to administer a compound of this invention in the form of an acid addition salt. Additionally, this invention includes quaternary ammonium salts of the compounds herein, which can be prepared by reacting the nucleophilic amines of the side chain with a suitably reactive alkylating agent such as an alkyl halide or benzyl halide.
Among the preferred compounds of this invention are those of the formula (I):
wherein
R 1 and R 2 are, independently, selected from H; C 1 -C 12 alkyl, preferably C 1 -C 6 alkyl; or C 1 -C 6 perfluorinated alkyl, preferably —CF 3 ;
X is a leaving group, such as halogen, —O—SO 2 —CH 3 , —O—SO 2 —CF 3 , or a moiety of the structure:
Z is selected from —NO 2 , halogen, —CH 3 or —CF 3 ;
A is selected from —O— or —S—, —SO— or —SO 2 —;
m is an integer from 0 to 3, preferably 1;
Y is selected from
a) the moiety:
wherein R 7 and R 8 are independently selected from the group of H, C 1 -C 6 alkyl, or phenyl.
b) a group selected from thiophene, furan, pyrrole, imidazole, pyrazole, thiazole, isothiazole, isoxazole, or oxathiolane, the group being optionally substituted with 1-3 substituents independently selected from the group consisting of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 R 1 , —NHCOR 1 , —NO 2 ;
c) a group selected from pyridine, pyrazine, pyrimidine, pyridazine, piperidine, morphonine and pyran, the group being optionally substituted with 1-3 substituents independently selected from the group consisting of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 , R 1 , —NHCOR 1 , —NO 2 ;
d) a group selected from azepine, diazepine, oxazepine, thiazepine, oxapin and thiepin, the group being optionally substituted with 1-3 substituents independently selected from the group consisting of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 R 1 , —NHCOR 1 , —NO 2 ; or
e) a bicyclic heterocycle selected from the group of benzofuran, isobenzofuran, benzothiophene, indole, isoindole, indolizine, indazole, purine, quinolizine, isoquinoline, quinoline, phthalazine, napthryidine, quinoxaline, quinazoline, and cinnoline, the group being optionally substituted with 1-3 substituents independently selected from the group consisting of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 R 1 , —NHCOR 1 , —NO 2 ; and the pharmaceutically acceptable salts thereof.
Further preferred compounds of this invention are those of the formula (I):
wherein:
R 1 and R 2 are, independently, selected from H; C 1 -C 12 alkyl, preferably C 1 -C 6 alkyl; or C 1 -C 6 perfluorinated alkyl, preferably —CF 3 ;
X is a leaving group, such as halogen, —O—SO 2 —CH 3 , —O—SO 2 —CF 3 , or a moiety of the structure:
Z is selected from —NO 2 , halogen, —CH 3 or —CF 3 ;
A is selected from —O— or —S—, —SO— or —SO 2 —;
m is an integer from 0 to 3, preferably 1;
Y is selected from:
a) the moiety:
wherein R 7 and R 8 are independently selected from the group of H, C 1 -C 6 alkyl, or phenyl; or
b) a group selected from thiophene, furan, pyrrole, imidazole, pyrazole, thiazole, pyridine, pyrazine, pyrimidine, pyridazine, piperidine, indole or benzofuran, the group being optionally substituted with 1-3 substituents independently selected from the group consisting of hydrogen, hydroxyl, halo, C 1 - 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 acyloxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, phenyl optionally substituted with 1-3 (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONHR 1 , —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 R 1 , —NHCOR 1 , —NO 2 ; and the pharmaceutically acceptable salts thereof.
Among the more preferred compounds of the present invention are those having the general formula
wherein:
R 1 and R 2 are, independently, selected from H, C 1 -C 6 alkyl or C 1 -C 6 perfluorinated alkyl, preferably, among the perfluorinated alkyl groups, —CF 3 ;
R 3 , R 4 , R 5 , and R 6 are independently selected from H, OH or the C 1 -C 4 esters or alkyl ethers thereof, halogen, —CN, C 1 -C 6 alkyl, or trifluoromethyl,
m is an integer from 0 to 3, preferably 1;
R 7 and R 8 are selected independently from H, C 1 -C 6 alkyl, or combined by —(CH 2 )p—, wherein p is an integer of from 2 to 6, so as to form a ring, the ring being optionally substituted by up to three substituents selected from the group of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONH(C 1 -C 4 ), —NH 2 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 (C 1 -C 4 ), —NHCO(C 1 -C 4 ), and —NO 3 ; and
X is as defined above; and the pharmaceutically acceptable salts thereof.
Also among the more preferred compounds of the present invention are those having the general formula
wherein:
R 1 and R 2 are, independently, selected from H, C 1 -C 6 akyl or C 1 -C 6 perfluorinated alkyl, preferably, among the perfluorinated alkyl groups, —CF 3 ;
R 3 , R 4 , R 5 , and R 6 are independently selected from H, OH or the C 1 -C 4 esters or alkyl ethers thereof, halogen, —CN, C 1 -C 6 alkyl, or trifluoromethyl,
m is an integer from 0 to 3, preferably 1;
A is selected from —S—, —SO— or —SO 2 —;
R 7 and R 8 are selected independently from H, C 1 -C 6 alkyl, or combined by —(CH 2 )p—, wherein p is an integer of from 2 to 6, so as to form a ring, the ring being optionally substituted by up to three substituents selected from the group of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONH(C 1 -C 4 ), —NH 3 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 (C 1 -C 4 ), —NHCO(C 1 -C 4 ), and —NO 2 ; and
X is as defined above; and the pharmaceutically acceptable salts thereof.
Among the most preferred compounds of the present invention are those having the structural formulas II or III, above, wherein R 3 -R 6 are as defined above; X is selected from the group of Cl, —CF 3 , or —CH 3 ; and Y is the moiety
and R 7 and R 8 are concatenated together as —(CH 2 )r—, wherein r is an integer of from 4 to 6, to form a ring optionally substituted by up to three substituents selected from the group of hydrogen, hydroxyl, halo, C 1 -C 4 alkyl, trihalomethyl, C 1 -C 4 alkoxy, trihalomethoxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, hydroxy (C 1 -C 4 )alkyl, —CO 2 H, —CN, —CONH(C 1 -C 4 ), —NH 3 , C 1 -C 4 alkylamino, C 1 -C 4 dialkylamino, —NHSO 2 (C 1 -C 4 ), —NHCO(C 1 -C 4 ), and —NO 2 ; and the pharmaceutically acceptable salts thereof.
It is further preferred that, when R 7 and R 8 are concatenated together as —(CH 2 )p— or —(CH 2 )r—, the ring so formed is optionally substituted with 1-3 substituents selected from a group containing C 1 -C 3 alkyl, trifluoromethyl, halogen, hydrogen, phenyl, nitro, —CN.
This invention also includes a process for making the compounds above. Compounds of this invention in which “A” is oxygen can be synthesized by the process steps of:
a) alkylating a relevant hydroxybenzaldehyde of the formula:
wherein R 3 -R 6 are as defined above, with a relevant alkyl halide of the formula:
wherein Y, R 1 , R 2 and m are as defined in the generic and subgeneric groups above and halo can be Cl, F, Br or I, to produce an aldehyde of the formula:
b) reducing the aldehyde product of step a), to yield the relevant alcohol having a formula:
c) converting the alcohol of step b) to its hydrochloride salt, such as with HCl/THF; and
d) converting the alcohol to a preferred leaving group, such as through treatment with methanesulfonyl chloride, toluenesulfonyl chloride, or trifluoroactic anhydride in the presence of a base like pyridine or triethylamine.
Similarly, the present invention provides a process for producing compounds of this invention wherein “A” is sulfur through the steps of:
a) alkylating a compound of the formula
with an alkylating agent of the formula:
wherein Y and m are as defined above and halo is selected from Cl, F, Br or I, to produce an aldehyde of the formula:
b) reduction of the aldehyde product of step a), such as with sodium borohydride, to an alcohol of the formula;
c) treatment of the alcohol of step b) with gaseous HCl to generate its hydrochloride; and
d) converting the alcohol hydrochloride product of step c) to a preferred leaving group, such as through treatment with methanesulfonyl chloride, toluenesulfonyl chloride, or trifluoroactic anhydride in the presence of a base like pyridine or triethylamine or continued treatment with HCl to form the corresponding benzyl chloride; and,
e) optionally, completing controlled oxidation of the sulfur to sulfoxide or to sulfone, such as with m-chloroperbenzoic acid.
The starting thiophenoxide aldehyde material of step a), above, may be generated from its corresponding thiophenol aldehyde, such as with sodium hydride, which may or may not be considered a step of the process, above.
DETAILED DESCRIPTION OF THE INVENTION
The following reactions Schemes I through IV demonstrate the synthesis of compounds of the present invention, utilizing different variables for “Y”. The reagents and solvents for the individual steps are given for illustrative purposes only and may be replaced by other reagents and solvents known to those skilled in the art.
Scheme IIa offers an alternative synthesis of the benzyl alcohols of this invention, exemplifying the synthesis of 4-(2-piperidinylethoxy)benzyl alcohol. In this synthesis 4-hydroxybenzyl alcohol is treated with a desired aryl amino alkyl chloride to afford the corresponding alkoxy benzyl alcohol. In the specific example of Scheme IIa, 4-hydroxybenzyl alcohol can be treated with 1-(2-chloroethyl)-piperidine hydrochloride in the presence of K 2 CO 3 /Me 2 CO to yield 4-(2-piperidinylethoxy)benzyl alcohol.
Scheme IIa also more specifically illustrates another preferred embodiment of the present invention. This invention also includes a process for producing useful alcohol compounds of the formula:
wherein Y represents the Y groups and their optional substituents as described most generically above.
In a preferred subgroup of this process, Y represents:
a) the moiety
wherein R 7 and R 8 are independently selected from the group of H, C 1 -C 6 alkyl, or phenyl; or
b) a five-, six- or seven-membered unsaturated or partially unsaturated heterocyclic ring containing one or two nitrogen atoms, the heterocyclic ring being bound to the ethoxy bridge at a nitrogen atom in the ring and being optionally substituted by from 1 to 3 groups selected from halogen, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, C 1 -C 6 thioalkyl, —CF 3 , or —NO 2 .
Among the preferred Y groups of this process are azepine, pyrrole, imidazoline, imidazolidine, hexamethyleneimine, pyrrolidine, pyrazolidine, pyrazoline, piperidine, piperazine,
The process comprises reacting, in an alkaline medium, 4-hydroxybenzyl alcohol with a salt, such as an acetate, hydrochloride, hydrobromide or hydroiodide salt, of a compound of the formula:
wherein Y is as defined above.
This reaction is carried out in an organic solvent or solvent system, such as in acetone, dimethylformamide or tetrahydrofuran. Preferably the pH of the medium is maintained above a pH of 8, more preferably above a pH of 9.
Utilizing similar steps, compounds of this invention wherein “A” is sulfur may be produced as shown in Scheme V, below. In a first step thiophenoxide may be produced with sodium hydride, followed by alkylation and reduction to the relevant aldehyde, such as with sodium borohydride or catalytically with Hydrogen and Raney Nickel or platinum or palladium on carbon catalysts. The resulting alcohol may then be treated with gaseous HCl to generate its hydrochloride, with continued HCl treatment to form a benzyl chloride. The final product may then be formed by controlled oxidation of the sulfur to sulfoxide, and then to sulfone, such as with m-chloroperbenzoic acid
The following examples are presented to illustrate rather than limit the scope of the invention
EXAMPLE 1
4-(2-piperidine -1-yl-ethoxy)-benzyl aldehyde (2a)
To a well-stirred slurry of phydroxybenzaldehyde (83.5 g, 0.68 mol, 1.05 eq.) and K 2 CO 3 (224 g, 1.6 mol, 2.5 eq.) in DMF (1 L), 1-(2-chloroethyl)piperidine hydrochloride (120 g, 0.65 mol, 1.0 eq.) is added. The reaction mixture is refluxed for 2 h with vigorous mechanical stirring. TLC at this point shows no starting material, mostly product (EtOAc/hexane 1:1). The reaction mixture is filtered through Celite, deluted with EtOAc (2 L), and washed with water (3×500 mL). The organic layer is concentrated on a rotary evaporator to give 147 g (97%) of aldehyde (2a) as a yellow oil.
1 H NMR (CDCl 3 /TMS): 9.87 (s, 1H), 7.81 (d, 2H, J=8.7 Hz), 7.01 (d, 2H, J=8.7 Hz), 4.18 (t, 2H, J=6.03 Hz), 2.79 (t, 2H, J=6.03 Hz), 2.51 (m, 4H), 1.6−1.4 (m, 6H)
EXAMPLE 2
4-(2-hexamethyleneimine-1-yl-ethoxy)-benzyl aldehyde (2b)
To a well-stirred slurry of NaH (65 g, 60% oil dispersion, 1.6 mol, 2.2 eq.) in DMF (500 mL) a solution of p-hydroxybenzaldehyde hydrochloride (90 g, 0.74 mol, 1.0 eq.) is added dropwise at 0° C. The reaction mixture is stirred for 30 min, then 4[2-(hexamethyleneimine)]ethylchloride (153 g, 0.77 mol, 1.0 eq.) is added in portions. The reaction mixture is stirred for 1 h TLC at this point shows little starting material, mostly product EtOAc/hexane 1:1). The reaction mixture is diluted with water (1 L), and extracted with ether (5 L). The organic layer is dried over MgSO 4 , and concentrated on a rotary evaporator to give 176.8 g (97%) of aldehyde (2b) as a yellow oil.
hu 1 H NMR (CDCl 3 /TMS): 9.87 (s, 1H), 7.81 (d, 2H, J=8.7 Hz), 7.02 (d, 2H, J=8.7 Hz), 4.14 (t, 2H, J=6.09 Hz), 2.98 (t, 2H, J=6.14 Hz), 2.78 (m, 4H), 1.66−1.61 (m, 8H)
EXAMPLE 3
4-(2-dimethylamino-ethoxy)-benzyl aldehyde (2c)
To a well-stirred slurry of phydroxybenzaldehyde (9.54 g, 0.078 mol, 1.00 eq.) and K 2 CO 3 (27 g, 0.195 mol, 2.5 eq.) in DMF (100 mL), 1-(2-chloroethyl)dimethylamine hydrochloride (11.26 g, 0.078 mol, 1.0 eq.) is added. The reaction mixture is stirred for 2 h at 60-70° C. TLC at this point shows no starting material, mostly product (EtOAc/hexane/Et 3 N 3:7:1). The reaction mixture is poured into waterline mixture (200 mL), and extracted with Et 2 O (3×200 mL). The organic layer is dried with MgSO 4 , and concentrated on a rotary evaporator to give 5.9 g (39%) of aldehyde (2c) as a pinkish liquid.
1 H NMR (CDCl 3 /TMS): 9.88 (s, 1H), 7.8 (d, 2H, J=8.7 Hz), 7.02 (d, 2H, J=8.7 Hz), 4.15 (t, 2H, J=5.64 Hz), 2.77 (t, 2H, J=5.64 Hz), 2.35 (s, 6H).
EXAMPLE 4
4-(2-piperidine-1-yl-ethoxy)-benzyl alcohol (3a)
To a stirred solution of the aldehyde 2a (115 g, 0.494 mol, 1.0 eq.) in methanol (360 mL) at 0/+5° C. sodium borohydride (9.44 g, 0.249 mol, 0.5 eq.) is added in portions. The reaction is stirred for 30 min. TLC at this point shows no starting material, mostly product (EtOAc/hexane/triethylamine 3:7:1). The reaction mixture is poured in water (1.1 L), extracted with methylene chloride (3×550 ml,), and dried over MgSO 4 . The solution is concentrated on a rotary evaporator to give 91.6 g (80%) of the alcohol 3a as a thick oil which crystallized instantly on seeding.
1 H NMR (CDCl 3 /TMS): 7.23 (d, 2H, J=8.5 Hz), 6.80 (d, 2H, J=8.5 Hz), 4.56 (s, 2H) 3.99 (t, 2H, J=6.12 Hz), 2.69 (t, 2H, J=6.14 Hz), 2.47 (m, 4H), 1.6−1.25 (m, 6H)
13 C NMR (DMSO-d 6 ): 158.23, 135.34, 128.70, 114.84, 66.42, 63.44, 58.27, 55.29, 26.45, 24.80
EXAMPLE 5
4-(2-piperldine-1-yl-ethoxy)-benzyl alcohol (3a)
4-hydroxybenzyl alcohol (6.2 g, 0.0.05 mol) was dissolved in aqueus sodium hydroxide (5N, 30 mL). Toluene (30 mL) was added followed by 1-(2-chloroethyl)piperidine hydrochloride (9.29 g, 0.05 mol) and benzyltriethylammonium bromide (0.3 g). The reaction mixture was heated with vigorous stirring for 1.5 h. The layers were separated, the aqueous layer was extracted with toluene (2×15 mL). Combined organic extracts and organic layer was washed with water (50 mL), brine (50 mL), dried over sodium sulfate, and concentrated on a rotary evaporator to give 8.725 g (75%) of alcohol (3a) as a yellowish brown oil.
EXAMPLE 6
4-(2-hexamethyleneimine -1-yl-ethoxy)-benzyl alcohol (3b)
To a stirred solution of the aldehyde 2b (200 g, 0.72 mol, 1.0 eq.) in methanol (400 mL) at 0/+5° C. sodium borohydzide (15.6 g, 0.41 mol, 0.57 eq.) is added in portions. The reaction is stirred for 30 min. TLC at this point shows no starting material, mostly product (EtOAc/hexane/triethylamine 3:7:1). The reaction mixture is diluted with water (400 mL), extracted with methylene chloride (3×400 mL), and dried over MgSO 4 . The solution is concentrated on a rotary evaporator to give 201 g (100%) of the alcohol 3b as a thick oil.
1 H NMR (CDCl 3 TMS): 7.27 (d, 2H, J=8.5 Hz), 6.87 (d, 2H, J=8.5 Hz), 4.60 (s, 2H), 4.05 (t, 2H, J=6.21 Hz), 2.93 (t, 2H, J=6.15 Hz), 2.77 (m, 4H), 1.7−1.5 (m, 8H)
EXAMPLE 7
4-(2-dimethylamino-ethoxy)-benzyl alcohol (3c)
To a stirred solution of the aldehyde 2c (5.9 g, 0.031 mol, 1.0 eq.) in methanol (20 mL) at 22° C. sodium borohydride (0.58 g, 0.015 mol, 0.5 eq.) is added in portions. The reaction is stirred for 30 min. TLC at this point shows no starting material, mostly product (EtOAc/hexane/triethylamine 5:5:1). The reaction mixture is diluted with water (50 mL), extracted with methylene chloride (3×40 mL), and dried over MgSO 4 . The solution is concentrated on a rotary evaporator to give 5.25 g (88%) of the alcohol 3c as a thick oil.
1 H NMR (CDCl 3 /TMS): 7.25 (d, 2H, J=8.64 Hz), 6.85 (d, 2H, J=8.64 Hz), 4.52) (s, 2H), 3.99 (t, 2H, J=5.88 Hz), 2.67 (t, 2H, J=5.79 Hz), 2.29 (s, 6H)
EXAMPLE 8
(4-Chloromethyl-phenoxy)-ethyl-piperidin-1-yl hydrochloride (1a)
A solution of the alcohol 3a (61.3 g, 0.26 mol, 1 eq.) in THF (500 mL) is cooled to 0/−5° C. (ice-water bath) and bubbled with gaseous HCl. Bubbling is continued until no more thickening of the reaction mixture occurred. The cooling bath is removed. Thionyl chloride (29 mL, 0.39 mol, 1.5 eq.) is added to the thick slurry of hydrochloride 4a, and the mixture is heated to 50° C. until clear. The reaction mixture is cooled to −3° C. and stirred for 30 min. The white solid obtained is filtered and dried to give 72 g (96%) of chloride 1a.
4a: 1 H NMR (DMSO-d 6 ): 10.9 (s, HCl), 7.25 (d, 2H, J=8.5 Hz), 6.94 (d, 2H, J=8.5 Hz), 4.42 (m, 4H), 3.41 (m, 4H)
1a: 1 H NMR (DMSO-d 6 ): 11 (br s, HCl), 7.39 (d, 2H, J=8.5 Hz), 6.99 (d, 2H, J=8.5 Hz), 4.74 (s, 2H), 4.46 (m, 2H), 3.45 (m, 4H), 2.69 (m, 2H) and 1.9−1.2 (m, 6H)
EXAMPLE 9
(4-Chloromethyl-phenoxy)-ethyl-hexamethyleneimine-1-yl hydrochloride (1b)
To a solution of the alcohol 3b (179 g, 0.72 mol, 1 eq.) in THF (300 mL) a solution of HCl (26.3 g of HCl in 263 mL of THF, 0.72 mol, 1.0 eq.) is added dropwise at 0/+10° C. A white precipitate is formed. Thionyl chloride (80 mL, 1.1 mol, 1.5 eq.) is added to the thick slurry of hydrochloride 4b, and the mixture is heated to 50° C. until clear. The reaction mixture is concentrated to 350 mL, and kept in refrigerator overnight. The white solid obtained is filtered, washed with cold THE (100 mL), and dried to give 147 g (67%) of chloride 1b.
1 H NMR (DMSO-d 6 ): 11 (br s, HCl), 7.40 (d, 2H, J=8.6 Hz), 7.00 (d, 2H, J=8.6 Hz), 4.74 (s; 2H), 4.44 (t, 2H, J=5.25), 3.64-3.39 (m, 4H), 3.25−3.17 (m, 2H), 1.84−1.54 (m, 8H)
EXAMPLE 10
(4-Chloromethyl-phenoxy)-ethyl-dimethylamino hydrochloride (1c)
To a solution of the alcohol 3c (5.25 g, 0.027 mol, 1 eq.) in THE (100 mL) gaseous HCl was bubbled at 0/+25° C. for 15 min. A white precipitate is formed. Thionyl chloride (6 mL, 9.6 g, 0.081 mol, 3.0 eq.) is added to the thick slurry of hydrochloride 4c, and the mixture is heated to 30° C. until clear. The reaction mixture is concentrated to 350 mL, and kept in refrigerator overnight. The white solid obtained is filtered, washed with cold THF (100 mL), and dried to give 4.57 g (68%) of chloride 1c.
Among the pharmacologically active compounds which may be produced using the compounds of the present invention are 2-Phenyl-1-[4-(2-aminoethoxy)-benzyl]-indole compounds which are useful as estrogenic agents. These compounds include those of the formulas IV and V, below:
wherein:
R 1 is selected from H, OH or the C 1 -C 12 esters (straight chain or branched) or C 1 -C 12 (straight chain or branched or cyclic) allyl ethers thereof, or halogens; or halogenated ethers including trifluoromethyl ether and trichloromethyl ether.
R 12 , R 9 , and R 10 are independently selected from H, OH or the C 1 -C 12 esters (straight chain or branched) or C 1 -C 12 alkyl ethers (straight chain or branched or cyclic) thereof, halogens, or halogenated ethers including triflouromethyl ether and trichloromethyl ether, cyano, C 1 -C 6 alkyl (straight chain or branched), or trifluoromethyl, with the proviso that, when R 1 is H, R 2 is not OH.
R 13 is selected from H, C 1 -C 6 alkyl, cyano, nitro, trifluoromethyl, halogen; and
Y, A, m, R 3 and R 4 are as defined herein.
The 2-Phenyl-1-[4-(2-aminoethoxy)-benzyl]-indole compounds of this type are partial estrogen agonists and display high affinity for the estrogen receptor. Unlike many estrogens, however, these compounds do not cause increases in uterine wet weight. These compounds are antiestrogenic in the uterus and can completely antagonize the trophic effects of estrogen agonists in uterine tissue. These compounds are useful in treating or preventing in a mammal disease states or syndromes which are caused or associated with an estrogen deficiency.
These compounds have the ability to behave like estrogen agonists by lowering cholesterol and preventing bone loss. Therefore, these compounds are useful for treating many maladies including osteoporosis, prostatic hypertrophy, infertility, breast cancer, endometrial cancer, cardiovascular disease, contraception, Alzheimer's disease and melanoma Additionally, these compounds can be used for hormone replacement therapy in post-menopausal women or in other estrogen deficiency states where estrogen supplementation would be beneficial.
The 2-Phenyl-1-[4-(2-aminoethoxy)-benzyl]-indole compounds produced with the compounds of this invention may also be used in methods of treatment for bone loss, which may result from an imbalance in a individual's formation of new bone tissues and the resorption of older tissues, leading to a net loss of bone. Such bone depletion results in a range of individuals, particularly in post-menopausal women, women who have undergone hysterectomy, those receiving or who have received extended corticosteroid therapies, those experiencing gonadal dysgenesis, and those suffering from Cushing's syndrome. Special needs for bone replacement can also be addressed using these compounds in individuals with bone fractures, defective bone structures, and those receiving bone-related surgeries and/or the implantation of prosthesis. In addition to those problems described above, these compounds can be used in treatments for osteoarthritis, Paget's disease, osteomalacia, osteohalisteresis, endometrial cancer, multiple myeloma and other forms of cancer having deleterious effects on bone tissues. Methods of treating the maladies listed herein are understood to comprise administering to an individual in need of such treatment a pharmaceutically effective amount of one or more of the compounds of this invention or a pharmaceutically acceptable salt thereof. This invention also includes pharmaceulical compositions utilizing one or more of the present compounds, and/or the pharmaceutically acceptable salts thereof, along with one or more pharmceutically acceptable carriers, excipients, etc.
It is understood that the dosage, regimen and mode of administration of these 2-Phenyl-1-[4-(2-aminoethoxyibenzyl]-indole compounds will vary according to the malady and the individual being treated and will be subject to the judgement of the medical practitioner involved. It is preferred that the administration of one or more of the compounds herein begin at a low dose and be increased until the desired effects are achieved.
Effective administration of these compounds may be given at a dose of from about 0.1 mg/day to about 1,000 mg/day. Preferably, administration will be from about 50 mg/day to about 600 mg/day in a single dose or in two or more divided doses. Such doses may be administered in any manner useful in directing the active compounds herein to the recipient's bloodstream, including orally, parenterally (including intravenous, intraperitoneal and subcutaneous injections), and transdermally. For the purposes of this disclosure, transdermal administrations are understood to include all administrations across the surface of the body and the inner linings of bodily passages including epithelial and mucosal tissues. Such administrations may be carried out using the present compounds, or pharmaceutically acceptable salts thereof, in lotions, creams, foams, patches, suspensions, solutions, and suppositories (rectal and vaginal).
Oral formulations containing the active compounds of this invention may comprise any conventionally used oral forms, including tablets, capsules, buccal forms, troches, lozenges and oral liquids, suspensions or solutions. Capsiles may contain mixtures of the active compound(s) with inert fillers and/or diluents such as the pharmaceutically acceptable starches (e.g. corn, potato or tapioca starch), sugars, artificial sweetening agents, powdered celluloses, such as crystalline and microcrystalline celluloses, flours, gelatins, gums, etc. Useful tablet formulations may be made by conventional compression, wet granulation or dry granulation methods and utilize pharmaceutically acceptable diluents, binding agents, lubricants, disintegrants, suspending or stabilizing agents, including, but not limited to, magnesium stearate, stearic acid, talc, sodium lauryl sulfate, microcrystalline cellulose, carboxymethylcellulose calcium, polyvinylpyrrolidone, gelatin, alginic acid, acacia gum, xanthan gum, sodium citrate, complex silicates, calcium carbonate, glycine, dextrin, sucrose, sorbitol, dicalcium phosphate, calcium sulfate, lactose, kaolin, mannitol, sodium chloride, talc, dry starches and powdered sugar. Oral formulations herein may be utilize standard delay or time release formulations to alter the absorption of the active compounds). Suppository formulations may be made from traditional materials, including cocoa butter, with or without the addition of waxes to alter the suppository's melting point, and glycerin. Water soluble suppository bases, such as polyethylene glycols of various molecular weights, may also be used.
As shown in Scheme VI, compounds of this group can be synthesized by alkylation of the indole nitrogen with compounds of the present invention, as illustrated in Examples 11-13, below, utilizing (4-Chloromethyl-phenoxy)-ethyl-piperidin-1yl hydrochloride of Example 8, (4-Chloromethyl-phenoxy)-ethyl-hexamethyleneimine -1-yl hydrochloride of Example 9 and (4-Chloromethyl-phenoxy)-ethyl-dimethylamino hydrochloride of Example 10, respectively. In addition to NaH, other bases may be used, including potassium t-butoxide or sodium t-butoxide.
Schemes VII and VII exemplify the synthesis of 1-[4-(2-Azepan-1-yl-ethoxy)-benzyl]2-(4-hydroxy-phenyl)-3-methyl-1H-indol-5-ol hydrochloride using intermediates of the present invention.
Scheme VII illustrates the alkylation of 4-hydroxybenzaldehyde with 2-(hexamethylamino)ethyl chloride hydrochloride, which can be accomplished in the presence of potassium carbonate to give corresponding aldehyde I (Step 1). When the reaction is complete the mixture may be clarified, mixed with toluene and washed with water. The toluene solution can then be concentrated and the resulting residue treated with isopropanol to give a solution of aldehyde I. The isopropanol solution of I may be treated to catalytic reduction, such as with Raney Nickel, to yield alcohol II (Step 2). Following reduction, the reaction mixture may be clarified and concentrated, with the resulting residue being dissolved in ethylene dichloride to give a solution containing alcohol II. This solution may be treated with thionyl chloride, followed by concentration. The resulting residue can then be treated with 1,2 dimethoxyethane to yield crystalline III (Step 3).
In Scheme VIII, Step 4, 4-Benzyloxypropiophenone is brominated in acetic acid with bromine. When the reaction is complete the mixture can be quenched with water and the resulting precipitate is washed with dilute acetic acid, water and heptane. The resulting solid is dried to give IV, 4-benzyloxyaniline hydrochloride. In Step 5, a mixture of IV, N,N-diisopropylethylamine and toluene is heated under reflux with removal of water. When the reaction is complete the mixture may be cooled and diluted with methanol. The solids produced can be collected, washed with methanol and dried to give compound indole V. A mixture of compounds V and III can be mixed in Step 6 with sodium tert-butoxide in N,N-dimethylformamide and stirred until the reaction is complete. Then the mixture may be quenched with brine and extracted with toluene. The extracts are concentrated and the residue diluted with methanol. The resulting solids may be collected, dissolved in ethyl acetate, clarified, and diluted with methanol. The solids may be collected from this dilution and dried to give compound VI.
In a Step 7 (not shown) compound VI in a solution of ethanol can be hydrogenated with a Pd-charcoal catalyst Following clarification, the hydrogenated material may be mixed with a small amount of ascorbic acid and treated with acetic acid. The resulting cystalline precipitate can then be collected, washed with ethanol and dried to give the final product, 1-[4-(2-Azepan-1-yl-ethoxy)-benzyl]2-(4-hydroxy-phenyl)3-methyl-1H-indol-5-ol hydrochloride. The product may then be recrystallized from ethanol, optionally containing a small amount of ascorbic acid, preferably such as from about 0.5% by weight to about 3.0% by weight.
In the descriptions above, intermediates III through VI may be readily isolated as solids. All other intermediates may be more preferably used as solutions in organic solvents.
Schemes IX through XII exemplify the synthesis of 2-(4-Hydroxy-phenyl)-3-methyl-1-[4-(2-piperidin-1-yl-ethoxy)benzyl]-1H-indol-5-ol utilizing intermediates of the present invention. Scheme IIa, described above, can be considered the first step of Scheme IX or a step prior thereto. In this step 4-hydroxybenzyl alcohol is treated with a desired aryl amino alkyl chloride to afford the corresponding alkoxy benzyl alcohol. In the specific example of Scheme IIa, 4-hydroxybenzyl alcohol is treated with 1-(2-chloroethyl)-piperidine hydrochloride in the presence of K 2 CO 3 /Me 2 CO to yield 4-(2-piperidinylethoxy)benzyl alcohol. Toluene and brine can be added to the resulting alcohol mixture to separate its phases. The toluene phase can then be washed Successively with aqueous alkali and brine. The resulting batch can then be concentrated and ethylene dichloride added to form a solution of the intermediate, 4-(2-piperidinylethoxy)benzyl alcohol.
The solution of 4-(2-piperidinyl-ethoxy)benzyl alcohol in ethylene dichloride can be combined with thionyl chloride and heated until the reaction is complete. Upon cooling, the mixture can be concentrated, followed by addition of 1,2-dimethoxyethane and additional concentration. The precipitate can be collected and dried to yield intermediate 4-(2-piperidinylethoxy)benzylchloride hydrochloride, as shown in Scheme IX.
As shown in Scheme IX, a solution of 4-(2-piperidinyl-ethoxy)benzyl alcohol can be combined with ethylene dichloride and thionyl chloride and heated to create a reaction mixture. Upon cooling, the reaction mixture can be treated with 1,2-dimethoxyethane and concentrated, again. The resulting precipitate, 4-(2-piperidinylethoxy)benzylchloride hydrochloride, can then be collected and dried.
Scheme X depicts the bromination of benzyloxypropiophenone in acetic acid with bromine to yield 4′-(benzyloxy)-2-bromopropiophenone. When this reaction is complete, the mixture can be quenched with water. The resulting precipitate can be collected, washed with dilute acetic acid, water and heptane, and dried.
The 4′-(benzyloxy)-2-bromopropiophenone product of Scheme X can be heated with 4-benzyloxyaniline hydrochloride in the presence of N,N-diisopropylethylamine and toluene under reflux with the azeotropic removal of water, as shown in Scheme XI. When the reaction is complete, the mixture can be cooled and diluted with methanol. The resulting solids of 3-methyl-2-(4-benzyloxy)phenyl-5-benzyloxyindole can be collected, washed with methanol and dried.
The 3-methyl-2-(4-benzyloxy)phenyl-5-benzyloxyindole product of Scheme XI can then be reacted with 4-(2-piperidinyl-ethoxy)benzylchloride hydrochloride in the presence of sodium tert-butoxide in N,N-dimethylformamide. The resulting mixture can be quenched with brine and extracted with toluene. Following clarification, the extracts can be concentrated and diluted with methanol. The resulting solids of 5-Benzyloxy-2-(4-benzyloxyphenyl)-1-[4-(2-piperidin-1-yl-ethoxy)benzyl]-1H-indole can be collected, dissolved in ethyl acetate and diluted with methanol and dried. These solids can be dissolved in ethanol-tetrahydrofuran and hydrogenated using Pd-charcoid catalyst. The solution may then be clarified, optionally mixed with a small amount of ascorbic acid and then treated with aqueous HCl. The precipitate can then be collected, washed with ethanol-tetahydrofuran and water and dried to yield the final product, of 2-(4-Hydroxy-phenyl)-3-methyl-1-[(2-piperidin-1-yl-ethoxy)-benzyl]-1H-indol-5-ol.
EXAMPLE 11
5-Benzyloxy-2-(4-benzyloxy-phenyl)-3-1-[4-(2-piperidin-1-yl-ethoxy)-benzyl]-1H-indole
To a solution of 5-Benzyloxy-2-(4-benzyloxy-phenyl)-3-methyl-1H-indole (117.5 g, 0.28 mol, 1.0 eq.) in DMF (1.3 L), NaH (28.0 g, 60% oil dispersion, 0.7 mol, 2.5 eq.) was added in portions at −5/−8° C. over 1 h. The reaction mixture was stirred for 2 h. A solution of the chloride from Example 8 in THF (1.0 L) was added dropwise at −10/0° C. over 2 h. The reaction mixture was stirred at 25° C. overnight. TLC at this point showed no starting material, mostly product (EtOAc/hexane 1:5). The reaction mixture was diluted with water (6 L), extracted with EtOAc (2×3 L), and dried over Na 2 SO 4 . The solution was concentrated to 1 L, poured in MeOH (2.5 L), and stirred for 1 h. The precipitate was filtered and dried to give the title compound (129 g, 73%).
1H NMR (CDCl 3 /TMS): 7.64−6.63 (m, 21H), 5.12 (s, 2H), 5.09 (s, 2H), 5.07 (s, 2H), 4.07 (t, 2H, J=6.06 Hz), 2.72 (t, 2H, J=6.06 Hz), 2.48 (m, 4H), 2.24 (s, 3H), 1.62−1.24 (m, 6H).
EXAMPLE 12
5-Benzyloxy-2-(4-benzyloxy-phenyl)-3-1-[4-(2-hexamethyleneimine-1-yl-ethoxy)-benzyl]-1H indole
To a slurry of NaH (20.0 g, 60% oil dispersion, 0.5 mol, 2.5 eq.) solution of 5-Benzyloxy-2-(4benzyloxy-phenyl)-3-methyl-1H-indole (84 g, 0.2 mol, 1.0 eq.) in DMF (100 L) was added at /0/+10° C. over 1 h. The reaction mixture was stirred for 30 min. A solution of the chloride from Example 9 (67 g, 0.22 mol, 1.1 eq.) in DMF (200 mL) was added dropwise at 0/+10° C. over 2 h. The reaction mixture was stirred at 25° C. for 2 h. TLC at this point showed no starting material, mosty product EtOAc/hexane 1:5). The reaction mixture was diluted with water (1 L), extracted with EtOAc (3×1 ), and dried over MgSO 4 . The solution was concent to 150 mL, poured in MeOH (750 mL), and stirred overnight. The precipitate was filtered and dried to give the title compound (99 g ,76%).
1 H NMR (CDCl 3 /TMS): 7.48−6.74 (m, 21H), 5.13 (s, 2H), 5.11 (s, 2H), 5.09 (s, 2H), 4.00 (t, 2H, J=6.24 Hz), 2.91 (t, 2H, J=6.27 Hz), 2.75 (m, 4H), 2.24 (s, 3H), 1.71−1.52 (m, 8H)
EXAMPLE 13
5-Benzyloxy-2-(4-benzyloxy-phenyl)-3-1-[4-(2-dimethylaminoethoxy)-benzyl]-1H indole
To a slurry of NaH (1.1 g, 60% oil dispersion, 0.05 mol, 2.5 eq.) solution of indole was added 5-Benzyloxy-2-(4benzyloxy-phenyl)-3methyl-1-indole (6.97 g, 0.017 mol, 1.0 eq.) in DM (100 mL) at 0/+10° C. over 0.5 h. The reaction mixture was stirred for 30 min. A solution of the chloride from Example 10 (4.57 g, 0.018 mol, 1.1 eq.) was added portion wise at 0/+10° C. over 2 h. The reaction mixture was stirred at 25° C. for 0.5 h. TLC at this point showed no starting material, mostly product (EtOAc/hexane 1:5). The reaction mixture was diluted with water (200 mL), extracted with EtOAc (3×200 ml), and dried over MgSO 4 . The solution was concentrated to 150 mL, poured in MeOH (300 mL), and stirred overnight. The precipitate was filtered and dried to give the tide compound 5.6 g (53%).
1H NMR (CDCl13/TMS): 7.50−6.66 (m, 21H), 5.13 (s, 2H), 5.11 (s, 2H), 5.09 (s, 2H), 3.99 (t, 2H, J=5.76 Hz), 2.69 (t, 2H, J=5.73 Hz), 2.31 (s, 6H), 2.42 (s, 3H)
EXAMPLE 14
5-benzyloxy-2-(4benzyloxyphenyl)-3-methyl-1H-indole
A flask was charged with 4-benzyloxyaniline (45 g, 0.23 mol), 4′-benzyloxy-2-bromophenylpropiophenone (66414-19-5) (21 g, 0.066 mol), and 50 mL DMF. The reaction was heated at reflux for 30 minutes and then cooled to rt and then partitioned between 250 mL EtOAc and 100 mL 1N HCl (aq). The EtOAc was washed with NaHCO 3 (aq) and brine, dried over MgSO 4 . The solution was concentrated and the residue taken up in CH 2 Cl 2 and hexanes added to precipitate out 25 g of a crude solid. The solid was dissolved in CH 2 Cl 2 and evaporated onto silica gel and chromatographed using CH 2 Cl 2 /Hexane (1:5) to yield 9.2 g of a tan solid (33%): Mpt=150-152° C.; 1 H NMR (DMSO) 10.88 (s, 1H), 7.56 (d, 2H, J=8.8 Hz), 7.48 (d, 4H, J=7.9 Hz), 7.42−7.29 (m, 6H), 7.21 (d, 1H, J=7.0 Hz), 7.13 (d, 2H, J=8.8 Hz), 7.08 (d, 1H, J=2.2 Hz), 6.94 (dd, 1H, J=8.8, 2.4 Hz), 5.16 (s, 2H), 5.11 (s, 2H), 2.33 (s, 3H); IR (KBr) 3470, 2880, 2820, 1620 cm −1 ; MS eI m/z 419.
EXAMPLE 15
2-(4-Hydroxy-phenyl)-3-methyl-1-[4-(2-piperidin-1-yl-ethoxy)-benzyl]-1H-indol-5-ol
A suspension of 10% Pd/C (1.1 g) in EtOH was treated with a solution of the title compound of Example 11 (2.2 g, 3.4 mmol) in THF/EtOH. Cyclohexadiene (6.0 mL, 63 mmol) was added and the reaction was stirred for 48 hours. The catalyst was filtered through Celite and the reaction mixture was concentrated and chromatographed on silica gel using a gradient elution of MeOH/CH 2 Cl 2 (1:19 to 1:10) to yield 0.8 g of the product as a white solid. Mpt=109-113° C.; CHN calc'd for C 29 H 32 N 2 O 3 +0.5 H 2 O; 1 H NMR 9.64 (s, 1H), 8.67 (s, 1H), 7.14 (d, 2 H, J=8.6 Hz), 7.05 (d, 1H, J=8.6 Hz), 6.84 (d, 2H, J=8.8 Hz), 6.79 (d, 1H, J=2.2 Hz), 6.74 (s, 4H), 6.56 (dd, 1H, J=8.8, 2.4 Hz), 5.09 (s, 2H), 3.95−3.93 (m, 2H), 2.60−2.51 (m, 2H), 2.39−2.38 (m, 4H), 2.09 (s, 3H), 1.46−1.45 (m, 4H), 1.35−1.34 (m, 2H); IR (KBr) 3350 (br), 2920, 1620, 1510 cm-1; MS (EI) m/z 456.
In vitro estrogen receptor binding assay
Receptor preparation
CHO cells overexpressing the estrogen receptor were grown in 150 mm 2 dishes in DMEM+10% dextran coated charcoal, stripped fetal bovine serum. The plates were washed twice with PBS and once with 10 mM Tris-HCl, pH 7.4, 1 mM EDTA. Cells were harvested by scraping the surface and then the cell suspension was placed on ice. Cells were disrupted with a hand-held motorized tissue grinder using two, 10-second bursts. The crude preparation was centrifuged at 12,000 g for 20 minutes followed by a 60 minute spin at 100,000 g to produce a ribosome free cytosol. The cytosol was then frozen and stored at −80° C. Protein concentration of the cytosol was estimated using the BCA assay with reference standard protein.
Binding assay conditions
The competition assay was performed in a 96-well plate (polystyrene) which binds <2.0% of the total input [ 3 H]-17 — -estradiol and each data point was gathered in triplicate. 100 uG/100 uL of the receptor preparation was aliquoted per well. A saturating dose of 2.5 nM [ 3 H] 17_-estradiol+competitor (or buffer) in a 50 uL volume was added in the preliminary competition when 100× and 500× competitor were evaluated, only 0.8 nM [ 3 H] 17_-estradiol was used. The plate was incubated at room temperature for 2.5 h. At the end of this incubation period 150 uL of ice-cold dextran coated charcoal (5% activated charcoal coated with 0.05% 69K dextran) was added to each well and the plate was immediately centrifuged at 99 g for 5 minutes at 4° C. 200 uL of the supernatant solution was then removed for scintillation counting. Samples were counted to 2% or 10 minutes, whichever occurs first. Because polystyrene absorbs a small amount of [ 3 H] 17_-estradiol, wells containing radioactivity and cytosol, but not processed with charcoal were included to quantitate amounts of available isotope. Also, wells containing radioactivity but no cytosol were processed with charcoal to estimate unremovable DPM of [ 3 H] 17_-estradiol. Corning # 25880-96, 96-well plates were used because they have proven to bind the least amount of estradiol.
Analysis of results
Counts per minute (CPM) of radioactivity were automatically converted to disintegrated per minute DPM) by the Beckman LS 7500 Scintillation Counter using a set of quenched standards to generate a H# for each sample. To calculate the % of estradiol binding in the presence of 100 or fold 500 fold competitor the following formula was applied:
((DPM sample-DPM not removed by charcoal/(DPM estradiol-DPM not removed by charcoal))×100%=% of estradiol binding
For the generation of IC 50 curves, % binding is plotted vs compound. IC 50 's are generated for compounds that show >30% competition at 500× competitor concentration. For a description of these methods, see Hulme, E. C., ed. 1992. Receptor-Ligand Interactions: A Practical Approach. IRL Press, New York.(see: especially chapter 8). Reference in the tables below to the compound of Example 1 refer to the final product, 2-(4-Hydroxy-phenyl)-3-methyl-1-[4-(2-piperidin-1-yl-ethoxy)-benzyl]-1H-indol-5-ol.
Estrogen Receptor Affinity
(reported as RBA: 17-estradiol = 100)
Compound
RBA
Raloxifene
200
Tamoxifen
1.8
Equilin
5.3
Example 15
400
Ishikawa Cell Alkaline Phosphatase Assay
Cell Maintenance and Treatment
Ishikawa cells were maintained in DMEM/F12 (50%:50%) containing phenol red+10% fetal bovine serum and the medium was supplemented with 2 mM Glutamax, 1% Pen/Strap and 1 EM sodium pyruvate. Five days prior to the beginning of each experiment (treatment of cells) the medium was changed to phenol red-freo DMEM/F12+10% dextran coated charcoal stripped serum. On the day before treatment, cells were harvested using 0.5% trypsin/EDTA and plated at a density of 5×10 4 cells well in 96well tissue culture plates. Test compounds were dosed at 10 −6 , 10 −7 and 10 −8 M in addition to 10 −6 M (compound)+10 −9 M 17_-estradiol to evaluate the ability of the compounds to function as antiestrogens. Cells were treated for 48 h prior to assay. Each 96-well plate contained a 17_-estradiol control. Sample population for at each dose was n= 8.
Alkaline Phosphatase Assay
At the end of 48h the media is aspirated and cells are washed three times with phosphate buffered saline (PBS). 50_L of lysis buffer ( 0.1 M Tris-HCl, pH 9.8, 0.2% Triton X-100) is added to each well. Plates are placed at −80° C. for a minimum of 15 minutes. Plates are thawed at 37° C. followed by the addition of 150_L of 0.1 M Tris-HCl, pH 9.8, containing 4 mM para-nitrophenylphosphate (pNPP) to each well (final concentration, 3 mM pNPP). Absorbance and slope calculations were made using the KineticCalc Application program (Bio-Tek Instruments, Inc., Winooski, Vt.). Results are expressed as the mean +/−S.D. of the rate of enzyme reaction (slope) averaged over the linear portion of the kinetic reaction curve (optical density reading:; every 5 minutes for 30 minutes absorbance reading). Results for compounds are summarized as percent of response related to 1 nM 17_estradiol. Various compounds were assayed for estrogenic activity by the alkaline phosphatase method and corresponding ED 50 values (95% C.I.) were calculated. The four listed in the following were used as as reference standards:
17_-estradiol
0.03 nM
17_-estradiol
1.42 nM
estriol
0.13 nM
estrone
0.36 nM
A description of these methods is described by Holinka, C. F., Hata, H., Kuramoto, H and Gurpide, E. (1986) Effects of steroid hormones and antisteroids on alkline phosphatase activity in human endometrial cancer cells (Ishikawa Line). Cancer Research, 46:2771-2774, and by Littlefield, B. A., Gurpide, E., Markiewicz, L., McKinley, B. and Hochberg, R. B. (1990) A simple and sensitive microtiter plate estrogen bioassay based on stimulation e phosphatase in Ishikawa cells; Estrogen action of D5 adrenal steroids. Endocrinology, 6:2757-2762.
Ishikawa Alkaline Phosphatase Assay
Compound
% Activation
17_-estradiol
100% activity
tamoxifen
0% activity (45% with 1 nM 17_-estradiol)
raloxifene
5% activity (5% with 1 nM 17_-estradiol)
Example 15
1% activity (1% with 1 nM 17_-estradiol)
2X VIT ERE Transfection Assay
Cell Maintenance and Treatment
Chinese Hamster Ovary cells (CHO) which had been stably transfected with the human estrogen receptor were maintained in DMEM+10% fetal bovine serum (FBS). 48 h prior to treatment the growth medium was replaced with DMEM lacking phenol red+10% dextran coated charcoal stripped FBS (treatment medium). Cells were plated at a density of 5000 cells/well in 96-well plates containing 200_L of medium/well.
Calcium Phosphate Transfection
Reporter DNA (Promega plasmid PGL2 containing two tandem copies of the vitellogenin ERE in front of the minimal thymidine kiase promoter driving the luciferase gene) was combined with the B-galactosidase expression plasmid pCH110 (Pharmacia) and carrier DNA (pTZ18U) in the following ratio:
10 uG of reporter DNA
5 uG of pCH 110 DNA
5 uG of pTZ18U
20 uG of DNA/1 mL of transfection solution
The DNA (2 uG) was dissolved in 500 uL of 250 mM sterile CACl 2 and added dropwise to 500 uL of 2×HeBS (0.28 M NaCl, 50 mM HEPES, 1.5 mM Na 2 HPO 4 , pH 7.05) and incubated at room temperature for 20 minutes. 20 uL of this mixture was added to each well of cells and remained on the cells for 16 h. At the end of this incubation the precipitate was removed, the cells were washed with media, fresh treatment media was replaced and the cells were treated with either vehicle, 1 nM 17_-estradiol, 1 uM compound or 1 uM compound +1 nM 17_-estradiol (tests for estrogen antagonism). Each treatment condition was performed on 8 wells (n=8) which were incubated for 24 h prior to the luciferase assay.
Luciferase Assay
After 24 h exposure to compounds, the media was removed and each well washed with 2× with 125 uL of PBS loading Mg ++ and Ca ++ . After removing the PBS, 25 uL of Promega lysis buffer was added to each well and allowed to stand at room temperature for 15 min, followed by 15 min at −80° C. and 15 min at 37° C. 20 uL of lysate was transferred to an opaque 96 well plate for luciferase activity evaluation and the remaining lysate (5 uL) was used for the B-galactosidase activity evaluation (normalize transfection). The luciferan substrate (Promega) was added in 100 uL aliquots to each well automatically by the luminometer and the light produced (relative light units) was read 10 seconds after addition.
Infection Luciferase Assay
Compound
% Activation
17_-estradiol
100% activity
estriol
38% activity
tamoxifen
0% activity (10% with 1 nM 17_-estradiol)
raloxifene
0% activity (0% with 1 nM 17_-estradiol)
Example 15
0% activity (0% with 1 nM 17_-estradiol)
B-Galactosidase Assay
To the remaining 5 uL of lysate 45 uL of PBS was added. Then 50 uL of Promega B-galactosidase 2× assay buffer was added, mixed well and incubated at 37° C. for 1 hour. A plate containing a standard curve (0.1 to 1.5 milliunits in triplicate) was set up for each experimental run. The plates were analyzed on a Molecular Devices spectrophotometric plate reader at 410 nm The optical densities for the unknown were converted to millunits of activity by mathematical extrapolation from the standard curve.
Analysis of Results
The luciferase data was generated as relative light units (RLUs) accumulated during a 10 second measurement and automatically transferred to a JMP (SAS Inc) file where background RLUs were subtracted. The B-galactosidase values verses automatically imported into the file and these values were divided into the RLUs to normalize the data. The mean and standard deviations were determined from a n=8 for each treatment. Compounds activity was compared to 17_-estradiol for each plate. Percentage of activity as compared to 17_-estradiol was calculated using the formula %=((Estradiol-control)/(compound value))× 100. These techniques are described by Tzukerman, M. T., Esty, A., Santiso-Mere, D., Danielian, P., Parker, M. G., Stein, R. B., Pike, J. W. and McDonnel D. P. (1994). Human estrogen receptor tansactivational capacity was determined by both cellular and promoter context and mediated by two functionally distinct intramolecular regions (see Molecular Endocrinology, 8:21-30).
Rat Uterotrophic/Antiuterotrophic Bioassay
The estrogenic and antiestrogenic properties of the compounds were determined in an immature rat uterotrophic assay (4 day) that (as described previously by L. J. Black and R. L. Goode, Life Sciences, 26, 1453 (1980)). Immature Sprague-Dawley rats (female, 18 days old) were tested in groups of six. The animals were treated by daily ip injection with 10 uG compound, 100 uG compound, (100 uG compound+1 uG 17_-estraiol) to check antiestrogenicity, and 1 uG 17_-estradiol, with 50% DMSO/50% saline as the injection vehicle. On day 4 the animals were sacrificed by CO 2 asphyxiation and their uteri were removed and stripped of excess lipid, any fluid removed and the wet weight determined A small section of one horn was submitted for histology and the remainder used to isolate total RNA in order to evaluate complement component 3 gene expression.
3 day Ovariectomized Rat Model
Compound
l0 uG
l00 uG
100 uG + 1 uG 17_-estradiol
Tamoxifen
69.6 mg
71.4 mg
Raloxifen
47.5
43.2
control = 42.7 mg
1 uG 17_-estradiol = 98.2
Example 15
39.9 mg
27.4 mg
24.3 mg
control = 30.7 mg
1 uG 17_-estradiol = 63.2
The compound Raloxifen [24-hydroxyphenyl)-6-hydroxybenzo[b]thien-3-yl][4-(1-piperidinylOethoxy]phenyl-methanone hydrochloride is representative of a class of compounds known to be selective estrogen receptor modulators, possessing estrogen agonist-like actions on bone tissues and scrum lipids while exhibiting estrogen antagonism in uterine and breast tissues. Palkowitz et al. suggest in J. Med. Chem 1997, 40, 1407 active analogs of Raloxifen which may also be produced utilizing the compounds of this invention. For instance, their disclosed compound 4a, [2-(4-hydroxyphenyl)-6-hydroxybenzo[b]thien-3-yl][4-(1-piperidinyl)ethoxy]methane hydrochloride can be produced by the general reaction scheme below.
EXAMPLE 16
2-(4-Methoxy-benzenesulfonylamino)-benzoic acid methyl ester
To a solution of 2.00 g (0.013 mol) of methyl anthranilate dissolved in 20 mL of chloroform was added 3.2 mL (0.039 mol) of pyridine followed by 2.733 g (0.013 mol) of p-methoxybenzenesulfonyl chloride. The reaction mixture was stirred at room temperature for 5 h and then washed with 3N HCl and water. The organics were then dried over Na 2 SO 4 , filtered and concentrated in vacuo. The resulting white solid was washed with ether and dried in vacuo to provide 3.7 g (87%) of the desired sulfonamide. CI Mass Spec: 322 (M+H).
EXAMPLE 17
2-(4-Methoxy-benzenesulfonylamino)-3-methyl-benzoic acid methyl ester
In the same manner as described in Example 16, 6.24 g (0.038 mol) of methyl-3-methyl-anthranilate provided 6.21 g (49%) of the desired sulfonamide as a white solid. Electrospray Mass Spec 336.2 (M+H).
EXAMPLE 18
4-(2-Piperidin-1-yl-ethoxy)-benzyl chloride
To a stirred solution of 4-hydroxy benzaldehyde (12.2 gm, 0.1 mol) and K2CO3 (25 gm, excess) in N,N-dimethilformainide (250 ml) was added 1-(2-chloroethyl)piperidine monohydrochloride (20.0 gm, 1.08 mol). The reaction mixture was heated to 80_C. for 24 hrs and cooled to room temperature. The reaction mixture was quenched with ice cold water and exacted with chloroform. The organics were washed with water, dried over anhydrous MgSO 4 , filtered and concentrated in vacuo. The residue was dissolved in methanol and sodium borohydride (10 gms, excess) was slowly added at 0_C. The reaction mixture was stirred at room temperature for 2 h and then quenched with water. The alcohol was extracted with chloroform, the organics were washed well with water, dried over Na 2 SO 4 , filtered and concentrated in vacuo.
The crude alcohol thus obtained was dissolved in THF (200 ml) and HCl gas was passed through for 30 minutes at 0_C. To the suspension of hydrochloride thus obtained, thionyl chloride ( 30 ml, excess) was slowly added. The reaction mixture was refluxed for thirty minutes and cooled to room temperature. The reaction mixture was then concentrated to dryness and triturated with anhydrous ether. The precipitated solid was filtered and dried under vacuum at room temperature to give 25 g (86%) of the product as a white solid. m.p. 145-148_C. Electrospray Mass Spec: 256 (M+H).
EXAMPLE 19
4-(2-N,N-Diethyl-ethoxy)-benzyl chloride
To a stirred solution of 4-hydroxy benzaldehyde (12.2 gm, 0.1 mol) and K 2 CO 3 (25 gm, excess) in N,N-dimethylformamide (250 ml) was added 2diethyl-aminoethyl chloride monohydrochloride (20.0 gm, 1.2 mol). The reaction mixture was heated at 80_C. for 24 hrs and cooled to room temperature. The reaction mixture was quenched with ice cold water and extracted with chloroform. The organics were washed with water, dried over anhydrous MgSO 4 , filtered and concentrated in vacuo. The residue was dissolved in methanol and sodium borohydride (10 gms, excess) was slowly added at 0_C. The reaction mixture was stirred at room temperature for 2 h and then quenched with water. The alcohol was extracted with chloroform, washed well with water, dried, filtered and concentrated in vacuo.
The crude alcohol thus obtained was dissolved in TBF (200 ml) and HCl gas was passed through for 30 minutes at 0_C. To the suspension of hydrochloride thus obtained, thionyl chloride ( 30 ml, excess) was slowly added. The reaction mixture was refluxed for thirty minutes and cooled to room temperature. The reaction mixture was then concentrated to dryness and triturated with anhydrous ether. The precipitated solid was filtered and dried under vacuum at room temperature to give 18 g (65%) of the product as a white solid, mp. 76-79_C. Electrospray Mass Spec: 244 (M+H).
EXAMPLE 20
N-Hydroxy-2-[[(4-methoxypheny l)sulfonyl][[4-[2-(1-piperidinyl)ethoxy]phenyl]methyl]amino]-3-methylbenzamide
To a solution of 1.00 g (2.985 mmol) of 2-(4-methoxy-benzene-sulfonylamino)ino)-3-methyl-benzoic acid methyl ester in 5 ml of DMF was added 0.952 g (3.284 mmol) of 4-(2-piperidin-1-yl-ethoxy)benzyl chloride and 1.65 g (11.9 mmol) of potassium carbonate. The reaction mixture was then stirred at room temperature for 18 h, diluted with water and extracted with ether. The organics were then extracted with 6 N HCl solution and the aqueous acid layer was then basified with 6 N NaOH solution and then extracted with ether. The resulting ether layer was dried over sodium sulfate, filtered and concentrated in vacuo to provide 0.965 g of the piperidine-ester as a colorless oil. Electrospray Mass Spec: 553.5 (M+H) + .
To a solution of 0.889 g (1.611 mmol) of piperidine ester in 7 ml of THF was added 0.203 g lithium hydroxide monohydrate. The resulting mixture was heated to reflux for 15 h, and then concentrated in vacuo to a residue. The residue was diluted with water, neutralized with 5% HCl solution and extracted with dichloromethane. The organic layer was dried over Na 2 SO 4 , filtered and concentrated in vacuo to provide 0.872 g of the carboxyl acid as a white foam. Electrospray Mass Spec: 539.2 (M+H) + .
To a solution of 0.814 g (1.513 mmol) of the carboxyl acid in 10 ml of DMF was added 0.245 g (1.82 mmol) of HOBT and 0.386 g (2.01 mmol) of EDC. The reaction was then stirred for 1 h at room temperature and 0.46 ml (7.57 mmol) of a 50% solution of hydroxylamine in water was added. The reaction was stirred overnight and then concentrated in vacuo to a residue. The residue was diluted with EtOAc, washed with water and sodium bicarbonate solution, dried over Na 2 SO 4 , filtered and concentrated in vacuo to a residue. The residue was dissolved in 5 ml of dichloromethane and 0.69 ml of a 1 N solution of HCl in ether was added After 1 h the reaction was diluted with ether and the resulting solid was filtered and dried to vacuo to give 0.179 g of the hydroxamate-amine salt as a white solid. Electrospray Mass Spec: 554.5 (M+H) + .
EXAMPLE 21
2-[[4-(2-Dimethylamino-ethoxy)-benzyl]-(4-methoxy-benzenesulfonyl)-amino]-N-hydroxy-3-methyl-benzamide
To a solution of 1.0 g (2.653 mmol) of 2-(4-methoxybenzene-sulfonylamino)-3-methylbenzoic acid methyl ester in 10 ml of DMF was added 0.811 g (2.918 mmol) of 4-(2-N,N-diethyl-ethoxy)-benzyl chloride and 1.5 g (10.9 mmol) of potassium carbonate. The reaction mixture was then stirred at room temperature for 18 h, diluted with water and extracted with ether. The organics were then extracted with 6 N HCl solution and the aqueous acid layer was then basified with 6 N NaOH solution and then extracted with ether. The resulting ether layer was dried over sodium sulfate, filtered and concentrated in vacuo to provide 0.575 g (37%) of the N,N-diethylamino-ester as a tan foam. Electrospray Mass Spec: 583.1 (M+H) + .
To a solution of 0.539 g (0.926 mmol) of the N,N-diethylamino-ester in dichloromethane was added 2 mL of trifluoroacetic acid. The reaction was stirred at room temperature for 2 h and then concentrated in vacuo to a residue. The residue was triturated with ether and the resulting solid was collected by filtration and dried in vacuo to give 0.369 g of the carboxylic acid as a white solid. Electrospray Mass Spec: 525.2 (M−) − .
To a solution of 0.328 g (0.513 mmol) the carboxylic acid in 6.5 ml of dichloromethane was added 0.12 ml of DMF followed by 0.77 ml of 2.0 M oxalyl chloride in CH 2 Cl 2 and the reaction mixture was stirred at room temperature for 1 h.
In a separate flask was added at 0° C. to a mixture of 0.47 mL (7.7 mmol) of a 50% solution of hydroxylamine in water 8 ml of THF and 1.7 ml of water. After this mixture had stirred for 15 minutes at 0° C., the acid chloride solution was added to it in one portion and the resulting solution was allowed to warm to room temperature with stirring overnight The reaction mixture was then acidified to pH 3 with 10% HCl and extracted with EtOAc. The combined organic layers were dried over Na 2 SO 4 , filtered and concentrated in vacuo to a residue. The residue is triturated with ether to provide 0.194 g of the hydroxamate-amine salt as a white solid. Electrospray Mass Spec: 542.3 (M+H) + .
EXAMPLE 22
2-(4-ethoxy-phenylsulfanyl)-propionic acid ethyl ester
To a stirred solution of 4-methoxybenzenethiol (2.5 gm, 14 mmol) and anhydrous K 2 CO 3 (4.0 gm, excess) in dry acetone (100 ml), ethyl 2-bromo-propionate (3.0 gm, 16 mmol) was added in a round bottom flask and the reaction mixture was heated at reflux for 8 hours with good stirring. At the end, reaction was allowed to cool, filtered and the reaction mixture was concentrated to a residue. The residue was extracted with chloroform and washed with H 2 O and the organic layer dried over MgSO 4 , filtered and concentrated to afford 2-(4methoxy-phenylsulfanyl)-propionic acid ethyl ester as a light yellow oil. Yield 3.6 gms (94%).
EXAMPLE 23
2-(4-Methoxy-benzenesulfonyl)-propionic acid ethyl ester
To a stirred solution of 12.0 gm (50 mmol) of 2-(4-methoxy-phenylsulfanyl)-propionic acid ethyl ester in 300 ml of methylene chloride at 0° C. was slowly added at a rate to control the exotherm. The reaction mixture was stirred at room temperature for 2 hours and diluted with 600 ml of hexanes. The reaction mixture was filtered and the filtrate stirred with 500 ml of a saturated Na 2 SO 3 solution for 3 hours. The organic layer was separated, washed well with water, dried and evaporated in vacuo to give 12 gm of a semi-solid.
EXAMPLE 24
2-(4-Methoxy-benzenesulfonyl)-2-methyl-3-[4-(2-piperidin-1-yl-ethoxy)-phenyl]propionic acid ethyl ester
To a stirred mixture of 2.7 g (10 mmol) of 2-(4-methoxy-benzenesulfonyl)propionic acid ethyl ester, 3.03 gm (10 mmol) 4-(2-piperidin-1-yl-ethoxy)benzyl chloride, 10 gm of K 2 CO 3 and 500 mg of 18-crown-6 in 250 ml of acetone was refluxed for 16 hours. At the end, the reaction mixture was filtered and the acetone layer was concentrated to a residue. The residue was extracted with chloroform, washed well with water, dried over anhydrous MgSO 4 , filtered and concentrated to a residue. The residue obtained was purified by silica-gel column chromatography by eluting with 50% ethyl acetate-hexanes to afford 4.8 gm (92%) of the desired product as an oil. MS: 490(M+H) + .
EXAMPLE 25
2-(4-Methoxybenzenesulfonyl)-2-methyl-3-[4-(2-piperidinyl-1-yl-ethoxy)-phenyl]-propionic acid
To a stirred solution of 2-(4methoxybenzenesulfonyl)-2-methyl-3-[4-(2-piperidin-1-yl-ethoxy)phenyl]propionic acid ethyl ester (4.9 gm, 10 mmol) in methyl alcohol was added 10 N NaOH (20 ml, excess). The reaction mixture was stirred at room temperature for 48 hours. At the end, the reaction mixture was concentrated and carefully neutralized with dilute HCl. The residue obtained was extracted with chloroform, washed well with water, dried and concentrated. The product obtained was purified by silica gel column chromatography by eluting with ethyl acetate:methanol (95:5) to afford the product of the example as colorless crystals, m.p. 106° C.; MS: 462.5 (M+H) + . Yield 4.1 gm, 88-1.
EXAMPLE 26
2-(4-Methoxybenzenesulfonyl)-2-methyl-3-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-propionamide
To a stirred solution of 2-(4-methoxy-phenylsulfonyl)-2-methyl-3-phenyl-[4-(2-piperidin-1-yl-ethoxy)]propionic acid (2.3 g, 5 mmol) of DMF (2 drops) in CH 2 Cl 2 (100 ml) at 0° C., oxalyl chloride (1.2 gm, 10 mmol) was added in a dropwise manner. After the addition, the reaction mixture was stirred at room temperature for 1 hour. Simultaneously, in a separate flask a mixture of hydroxylamine hydrochloride (3.4 gm, 50 mmol) of triethylamine (10.1 gm, 100 mmol) was stirred in TBF:water (5:1, 50 ml) at 0° C. for 1 hour. At the end of 1 hour, the oxalyl chloride reaction mixture was concentrated and the pale yellow residue was dissolved in 10 ml of CH 2 Cl 2 and added slowly to the hydroxylamine at 0° C. The reaction mixture was stirred at room temperature for 24 hours and concentrated. The residue obtained was extracted with chloroform and washed well with water. The product obtained was purified by silica gel column chromatography and eluted with ethyl acetate. The product of the example was isolated as a colorless solid. mp 98° C.; Yield, 48%; MS: 477 (M+H) + ; 1H NMR (300 MHz, CDCl 3 ): — 1.2 (s, 3H), 3.5−1.5 (m, 16H), 3.9 (s, 3H), 4.4 (m, 1H); 6.5-7.8 (m, 8H); 10.8 (bs, 1H).
The subject compounds of the present invention were tested for biological activity according to the following procedures.
In Vitro Gelatinase Assay
The assay is based on the cleavage of the thiopeptide substrate ((Ac-Pro-Leu-Gly(2 mercapto-4 methyl-pentanoyl)-Leu-Gly-OEt), Bachem Bioscience) by the enzyme, gelatinase, releasing the substrate product which reacts colorimetrically with DTNB ((5,5′-dithio-bis(2-nitro-benzoic acid)). The enzyme activity is measured by the rate of the color increase. The thiopeptide substrate is made up fresh as a 20 mM stock in 100% DMSO and the DINB is dissolved in 100% DMSO as a 100 mM stock and stored in dark at room temperature. Both the substrate and DTNB are diluted together to 1 mM with substrate buffer (50 mM HEPES pH 7.5, 5 mM CaCl 2 ) before use. The stock of human neutrophil gelatinase B is diluted with assay buffer (50 mM HEPES pH 7.5, 5 mM CaCl 2 , 0.02% Brij) to a final concentration of 0.15 nM. The assay buffer, enzyme, DTNB/substrate (500 μM final concentration) and vehicle or inhibitor are added to a 96 well plate (total reaction volume of 200 μl) and the increase in color is monitored spectrophotometrically for 5 minutes at 405 nm on a plate reader. The increase in OD 405 is plotted and the slope of the line is calculated which represents the reaction rate. The linearity of the reaction rate is confirmed (r 2 >0.85). The mean (x±sem) of the control rate is calculated and compared for statistical significance (p<0.05) with drug-treated rates using Dunnett's multiple comparison test. Dose-response: relationships can be generated using multiple doses of drug and IC 50 values with 95%, CI are estimated using linear regression (IPRED, HTB).
References: Weingarten, H and Feder, J., Spectrophotometric assay for vertebrate collagenase, Anal. Biochem. 147, 437-440 (1985).
In Vitro Collagenase Assay
The assay is based on the cleavage of a peptide substrate ((Dnp-Pro-Cha-Gly-Cys(Me)-His-Ala-Lys(NMa)—NH 2 ), Peptide International, Inc.) by collagenase releasing the fluorescent NMa group which is quantitated on the fluorometer. Dnp quenches the NMa fluorescence in the intact substrate. The assay is run in HCBC assay buffer (50 mM HEPES, pH 7.0, 5 mM Ca +2 , 0.02% Brij, 0.5% Cysteine), with human recombinant fibroblast collagenase (truncated, mw=18,828, WAR, Radnor). Substrate is dissolved in methanol and stored frozen in 1 mM aliquots. Collagenase is stored frozen in buffer in 25 μM aliquots. For the assay, substrate is dissolved in HCBC buffer to a final concentration of 10 μM and collagenase to a final concentration of 5 nM. Compounds are dissolved in methanol, DMSO, or HCBC. The methanol and DMSO are diluted in HCBC to <1.0%. Compounds are added to the 96 well plate containing enzyme and the reaction is started by the addition of substrate. The reaction is read (excitation 340 nm, emission 444 nm) for 10 min. and the increase in fluorescence over time is plotted as a linear line. The slope of the line is calculated and represents the reaction rate. The linearity of the reaction rate is confirmed (r 2 >0.85). The mean (x±sem) of the control rate is calculated and compared for statistical significance (p<0.05) with drug-treated rates using Dunnett's multiple comparison test. Dose-response relationships can be generated using multiple doses of drug and IC 50 values with 95% CI are estimated using linear regression (IPRED, HTB) .
References: Bickett, D. M. et al., A high throughput fluorogenic substrate for interstitial collagenase (MMP-1) and gelatinase (MMP-9), Anal. Biochem. 212,58-64 (1993).
Procedure for Measuring TACE Inhibition
Using 96-well black microtiter plates, each well receives a solution composed of 10 μL TACE (Immunex, final concentration 1 μg/mL), 70 μL Tris buffer, pH 7.4 containing 10% glycerol (final concentration 10 mM), and 10 pL of test compound solution in DMSO (final concentration 1 μM, DMSO concentration <1%) and incubated for 10 minutes at room temperature. The reaction is initiated by addition of a fluorescent peptidyl substrate (final concentration 100 μM) to each well and then shaking on a shaker for 5 sec. The reaction is read (excitation 340 nm, emission 420 mn) for 10 min. and the increase in fluorescence over time is plotted as a linear line. The slope of the line is calculated and represents the reaction rate. The linearity of the reaction rate is confirmed (r 2 >0.85). The mean (x±sem) of the control rate is calculated and compared for statistical significance (p<0.05) with drug-treated rates using Dunnett's multiple comparison test. Dose-response relationships can be generate using multiple doses of drug and IC 50 values with 95% CI are estimated using linear regression.
The results obtained following these standard experimental test procedures are presented in the following table.
IC 50 (nM or % inhibition at 1 micromolar)
Example
MMP 1
MMP 9
MMP 13
TACE
26
238.6
8.9
1.4
41.00%
Procedures for Measuring MMP-1, MMP-9, and MMP-13 Inhibition
These assays are based on the cleavage of a thiopeptide substrates such as Ac-Pro-Leu-Gly(2-mercapto-4-methyl-pentanoyl)-Leu-Gly-OEt by the matrix metalloproteinases MMP-1, MMP-13 (collagenases) or MMP-9 (gelatinase), which results in the release of a substrate product that reacts colorimetrically with DTNB (5,5′-dithiobis(2-nitro-benzoic acid)). The enzyme activity is measured by the rate of the color increase. The thiopeptide substrate is made up fresh as a 20 mM stock in 100% DMSO and the DTNB is dissolved in 100% DMSO as a 100 mM stock and stored in the dark at room temperature. Both the substrate and DTNB ate diluted together to 1 mM with substrate buffer (50 mM HEPES pH 7.5, 5 mM CaCl 2 ) before use. The stock of enzyme is diluted with assay buffer (50 mM HEPES, pH 7.5, 5 nM CaCl 2 , 0.02% Brij) to the desired final concentration. The assay buffer, enzyme, vehicle or inhibitor, and DTNB/substrate are added in this order to a 96 well plate (total reaction volume of 200 μl) and the increase in color is monitored spectrophotometrically for 5 minutes at 405 nm on a plate reader and the increase in color over time is plotted as a linear line.
Alternatively, a fluorescent peptide substrate is used. In this assay, the peptide substrate contains a fluorescent group and a quenching group. Upon cleavage of the substrate by an MMP, the fluorescence that is generated is quantitated on the fluorescence plate reader. The assay is run in HCBC assay buffer (50 mM HEPES, pH 7.0, 5 mM Ca +2 , 0.02% Brij, 0.5% Cysteine), with human recombinant MMP-1, MMP-9, or MMP-13. The substrate is dissolved in methanol and stored frozen in 1 mM aliquots. For the assay, substrate and enzymes are diluted in HCBC buffer to die desired concentrations. Compounds are added to the 96 well plate containing enzyme and the reaction is started by the addition of substrate. The reaction is read (excitation 340 nm, emission 444 nm) for 10 min. and the increase in fluorescence over time is plotted as a linear line.
For either the thiopeptide or fluorescent peptide assays, the slope of the line is calculated and represents the reaction rate. The linearity of the reaction rate is confirmed (r 2 >0.85). The mean (x±sem) of the control rate is calculated and compared for statistical significance (p<0.05) with drug-treated rates using Dunnett's multiple comparison test. Dose-response relationships can be generated using multiple doses of drug and IC 50 values with 95% CI are estimated using linear regression.
In vivo MMP Inhibition
A 2 cm piece of dialysis tubing (molecular weight cut-off 12-14,000, 10 mm flat width) containing matrix metalloproteinase enzyme (stromelysin, collagenase or gelatinase in 0.5 mL of buffer) is implanted either ip or sc (in the back) of a rat (Sprague-Dawley, 150-200 g) or mouse (CD-1, 25-50 g) under anesthesia Drugs are administered PO, IP, SC or IV through a canula in the jugular vein. Drugs are administered in a dose volume of 0.1 to 0.25 mL/animal. Contents of the dialysis tubing is collected and enzyme activity assayed
Enzyme reaction rates for each dialysis tube are calculated. Tubes from at least 3 different animals are used to calculate the means sem. Statistical significance (p<0.05) of vehicle-treated animals versus drug-treated animals is determined by analysis of variance. (Agents and Actions 21:331, 1987).
Procedure for Measuring TACE Inhibition
Using 96-well black microtiter plates, each well receives a solution composed of 10 μL TACE (Immunex, final concentration 1 μg/mL), 70 μg/mL), 70 μL Tris buffer, pH 7.4 containing 10% glycerol (final concentration 10 mM), and 10 μL of test compound solution in DMSO (final concentration 1 μM, DMSO concentration <1%) and incubated for 10 minutes at room temperature. The reaction is initiated by addition of a fluorescent peptidyl substrate (final concentration 100 μM) to each well and then shaking on a shaker for 5 sec.
The reaction is read (excitation 340 nm, emission 420 nm) for 10 min. and the increase in fluorescence over time is plotted as a linear line. The slope of the line is calculated and represents the reaction rate.
The linearity of the reaction rate is confirmed (r 2 >0.85). The mean (x±sem) of the control rate is calculated and compared for statistical significance (p<0.05) with drug-treated rates using Dunnett's multiple comparison test. Dose-response relationships can be generate using multiple doses of drug and IC 50 values with 95% CI are estimated using linear regression.
Results of the above in-vitro and in-vivo matrix metalloproteinase inhibition and TACE inhibition pharmacological assays are given in Table I below.
TABLE I
Inhibition of MMP and TACE
in-vivo
Example
MMP-1 1
MMP-9 1
MMP-13 1
MMP 2
TACE 1
20
176
6.9
56
277
21
96
2.3
8.8
215
1 IC 50 nM or % inhibition at 1 μM concentration
2 % inhibition vs. MMP-9 (dose, mg/kg), ip = intraperitoneal, po = oral
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The present invention provides compounds useful in the synthesis of biologically active compounds, and processes for their production, the compounds having the formula:
wherein: R 1 and R 2 are, independently, selected from H; C 1 -C 12 alkyl or C 1 -C 6 perfluorinated alkyl; X represents a leaving group; A is O or S; m is an integer from 1 to 3, preferably 2; R 3 , R 4 , R 5 , and R 6 are independently selected from H, halogen, —NO 2 , alkyl, alkoxy, C 1 -C 6 perfluorinated alkyl, OH or the C 1 -C 4 esters or alkyl ethers thereof, —CN, —O—R 1 , —O—Ar, —S—R 1 , —S—Ar, —SO—R 1 , —SO—Ar, —SO 2 —R 1 , —SO 2 —Ar, —CO—R 1 , —CO—Ar, —CO 2 —R 1 , or —CO 2 —Ar; and Y is selected from a) the moiety:
wherein R 7 and R 8 are independently selected from the group of H, C 1 -C 6 alkyl, or phenyl; or b) an optionally substituted five-, six- or seven-membered saturated, unsaturated or partially unsaturated heterocycle or bicyclic heterocycle containing up to two heteroatoms selected from the group consisting of —O—, —NH—, —N(C 1 C 4 alkyl)—, —N═, and —S(O) n —.
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CROSS REFERENCE TO RELATED PATENT APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 13/106,696, filed May 12, 2011, which claims priority to U.S. Provisional Patent Application No. 61/334,543, filed May 13, 2010, incorporated herein by reference in its entirety.
STATEMENT OF GOVERNMENT INTEREST
The United States Government claims certain rights in this invention pursuant to Contract No. W-31-109-ENG-38 between the United States Government and the University of Chicago and/or pursuant to DE-AC02-06CH11357 between the United States Government and UChicago Argonne, LLC representing Argonne National Laboratory.
FIELD OF THE INVENTION
The present invention relates generally to the field of electrocatalysts. More particularly the invention relates to non-Pt and non-precious metal electrocatalysts and methods of preparation. Preferred metals, such as transition metals, are incorporated into porous polymers which provide active ligation sites to interact with the transition metals.
BACKGROUND OF THE INVENTION
A fuel cell is an effective device that can convert chemical energy into electrical energy through electro-catalytic reactions. A proton exchange membrane fuel cell (hereinafter, “PEMFC”.) operates at a relatively low temperature with a gas phase hydrogen provided as fuel and oxygen (air) as an oxidant. Due to its high conversion efficiency, low noise and low emissions, PEMFC has high potential for many uses in automobile applications and distributed power generation.
At the core of a PEMFC is the membrane electrode assembly (hereinafter, “MEA”) which includes an anode, a cathode and a polymer electrolyte layer in-between. At the surface of the anode, hydrogen is oxidized to a proton started through the electro-catalytic process,
H 2 →2H + +2 e − (1)
The protons thus produced are transported to the cathode side through a proton conductive membrane. At the surface of the cathode, oxygen is electro-catalytically reduced and subsequently reacts with protons from the equation (1) to form water,
O 2 +4 e − +4H + →2H 2 O (2)
The reaction (2) is also known as the oxygen reduction reaction (hereinafter referred to as “ORR”). The reactions (1) and (2) occur on the surface of the electrode catalysts. At present, the most effective catalysts for these reactions are made of platinum supported on amorphous carbon. A typical Pt loading on the MEA surface ranges from 0.2 mg/cm 2 to 0.4 mg/cm 2 . Since platinum is a precious metal with limited supply, its usage adds a significant cost to a PEMFC system.
Consequently, there is a substantial need for replacement materials for the catalyst to reduce costs and insure adequate material supplies for wide scale use in fuel cells, as well as other applications. Few catalyst metals have been found to have a comparable catalytic efficiency as that of platinum for the ORR. Those catalysts found with similar catalytic activity usually belong to the precious group metals (hereinafter referred to as “PGM”), such as Pd, Rh, Ir, Ru and others, in addition to Pt. The PGMs generally are very costly due to limited reserves worldwide. As noted hereinbefore, the use of PGMs for an electrochemical device, such as fuel cells, will add significant cost to the system, therefore, creating major barriers for commercialization.
There have been many attempts to replace PGMs, mainly through use of the transition metal compounds. For example, it has been known that the molecules containing a macrocyclic structure with an iron or cobalt ion coordinated by nitrogen from the four surrounding pyrrolic rings have the catalytic activity to capture and to reduce molecular oxygen. It has been demonstrated that ORR catalytic activity can be further improved for such systems containing coordinated FeN 4 and CoN 4 macrocycles if they have been heat-treated. Examples of macro-molecular system containing FeN 4 and CoN 4 moieties include corresponding transitional metal phthalocyanine and porphyrin. Recent experiments have shown a similar method of making amorphous carbon based catalyst with good ORR activity by mixing macromolecules with FeN 4 group and carbonaceous material or synthetic carbon support, followed by high temperature treatment in the gas mixture of ammonia, hydrogen and argon. Alternative study also found that high temperature treatment of iron salt deposited on the carbon in the presence nitrogen precursor can also produce catalyst with very good ORR activity. The catalytic activity is attributed to the active site with a phenanthroline type structure where Fe ion is coordinated to four pyridinic nitrogens. It was also found that the catalyst thus produced decomposed in an acidic condition to release iron, and thus is unstable for the electro-catalytic reaction such as for inside a fuel cell cathode. Recently, an issued U.S. patent discussed a method of preparing non-PGM catalyst by incorporating transition metal to heteroatomic polymers in the polymer/carbon composite. In addition, this patent further discussed a method to improve the activity of polymer/carbon composite by heat-treating the composite at elevated temperature in the inert atmosphere of nitrogen. Nevertheless, none of these methods or articles of manufacture have resulted in an adequate solution to the above stated problem of replacement materials of reasonable cost and adequate supplies for large scale use in fuel cells, as well as other applications requiring such catalysts.
SUMMARY OF THE INVENTION
A new method and composition is provided for an electrode catalyst, preferably for an oxygen reduction reaction (“ORR”). The catalyst preferably includes transition metals, carbon and nitrogen, but free of platinum group metals (“PGM”). The method of preparation involves multiple steps, including the synthesis of porous polymers with intrinsic porosity and high surface area, the polymers containing ligand groups as anchoring sites for transition metal; adding one or more transition metals through chemical doping to the anchoring site, optionally adding other nitrogen containing compounds into the porous polymers; calcining the prepared polymers to form carbonaceous materials at elevated temperatures in an inert atmosphere, optionally treating the calcined polymer materials at the elevated temperature in the presence of ammonia and optionally treating the calcined materials with acid.
One embodiment of the current invention includes preparing porous polymers as the precursors for a non-PGM catalyst. The method of synthesis of high surface area precursors include providing porous polymers containing functional groups that can serve as ligation sites to interact with the transition metals to be dispersed therein. The porous polymers are prepared through cross-linking of monomers with stereo-contorted core and nitrogen-containing, oxygen-containing, or sulfur-containing molecules. Generally, the monomers with stereo-contorted core are used to generate micropore, mesopore and high surface area whereas the monomers with N-, O- or S-containing functional groups are used to produce ligation sites for transition metal inside of the porous polymers. Such polymers have high surface areas and uniform pore size distribution and can be used as platform or substrate materials for preparing non-PGM catalysts through further processing.
Another embodiment includes incorporation of a transition metal uniformly throughout the porous polymer. The methods include adding and exchange of atomically dispersed transition metals into individual ligation site for preparing non-PGM catalysts through further processing. The preferred transition metals include Co, Fe, Ni, Cr, Cu, Mn, Ta and W. They can be in the form of soluble organometallic compounds or inorganic salts. One or more transition metals can also be used simultaneously during preparation.
Yet another embodiment includes optional impregnation of nitrogen-containing organic compounds into the porous polymers. The porous structure of the selected polymers makes it relative easy to entrap nitrogen-containing organic compounds through various physical and chemical means. The added nitrogen-containing organic compounds can assist the formation of catalytic sites during the heat-treatment process.
In a further embodiment, the porous polymer is activated by thermal treatment, such as pyrolysis in an inert or reducing atmosphere. Such treatment can lead to decomposition and reaction between different components inside the polymers to form catalytic active sites. Such an activation process will also improve the electronic conductivity which is important for best function of the electrode catalyst.
In another embodiment the porous polymer is further processed by thermally treating the porous polymers with post-treatment methods, including acid wash, ball milling and a second thermal treatment in inert gas or in the presence of ammonia. Such post-treatment methods can further enhance the activity. In one aspect, one method of preparing an electroactive material is provide which includes: preparing a porous polymer; adding a precursor consisting essentially of one or more transition metals to the porous polymer; and activating transition metals disposed in the porous polymer by thermal treatment. In some embodiments, the method includes addition of a N-containing compound to the porous polymer. In some embodiments, the method further includes the step of adding N-containing organic compounds during the step of adding the transition metal precursor to the porous polymer.
In some embodiments, preparing the porous polymer includes a cross-linking reaction. In some embodiments, the cross-linking reaction includes adding a catalytic agent comprising FeCl 3 . In some embodiments, the cross-linking reaction includes adding a voltage bias to the monomer solution while preparing the porous polymer. In some embodiments, preparing the porous polymer includes cross-linking at least one organic monomer with a functional group selected from ethynyl, thiophenyl, amino, ketone, aldehyde and carboxylic anhydride. In some embodiments, preparing the porous polymer includes cross-linking organic monomers with a stereo-hindered group. In some embodiments, the monomer includes a N-coordination site for incorporating a transition metal.
In some embodiments, activating the transition metals includes calcining the porous polymer to form a carbonaceous material in an inert gas atmosphere. In some embodiments, the carbonaceous material is treated at an elevated temperature in the presence of N-containing compounds selected from ammonia, pyridine or acetonitrile. In some embodiments, activating the transition metal sites includes adding a metal complex selected from the group of Co(hfac) 2 , Fe (hfac) 2 and Ni(hfac) 2 wherein hfac is hexafluoroacetylacetonate. In some embodiments, the transition metals are selected from the group of Co, Fe, Ni, Cr, Cu, Mn, Ta and W. In one aspect, the method includes post-treatment.
In one aspect, an electrocatalyst is provided which includes a porous polymer containing transitional metal ligation groups disposed in the porous polymer and at least one transition metal attached to the transition metal ligation group. In some embodiments, the electrocatalyst consists essentially of the porous polymer and at least one transition metal. In some embodiments, the transition metal is selected from the group of Co, Fe, Ni, Cr, Cu, Mn, Ta and W.
In some embodiments, the porous polymer includes a precursor consisting essentially of a product formed by a cross-linking reaction involving at least one monomer. In some embodiments, the porous polymer comprises a precursor consisting essentially of a product formed by a cross-linking reaction involving at least one of a first monomer and a second monomer. In some embodiments, the first monomer is selected from the group of a monomer containing N-coordinating sites for incorporating the transition metal. In some embodiments, the second monomer consists essentially of a monomer containing a stereo-contorted structure for producing porosity and increased surface area. In some embodiments, the stereo-contorted structure is selected from a structural element group of spirobifluorene, tetraphenylmethane, and triphenylamine substituted with different functional groups.
In some embodiments, the cross-linking reaction involving oxidative coupling of a first monomer of porphyrin with thiophenyl functional groups catalyzed by FeCl 3 or by constant voltage bias. In some embodiments, the cross-linking reaction involving trimerization of a first monomer containing ethynyl functional groups and a second monomer containing a stereo-contorted structure in claim 7 catalyzed by a transition metal catalyst. In some embodiments, the cross-linking reaction involving trimerization of at least one of a first monomer containing cyano groups and a second monomer containing a stereo-contorted structure catalyzed by trifluoromethylsulfonic acid or lewis acid. In some embodiments, the cross-linking reaction includes a catalytic homocoupling of a first monomer containing arylbromide or ethynyl groups and an optional second monomer containing a stereo-contorted structure. In some embodiments, the cross-linking reaction involves a condensation coupling of a first monomer containing ketone, aldehyde, or anhydride and a second monomer containing arylamine. In some embodiments, the cross-linking reaction involves a first monomer containing chloromethyl group and a second monomer containing a stereo-contorted structure through Friedel Crafts reaction. In one aspect, a fuel cell is provided which includes the electrocatalyst as a substrate in the anode or cathode.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 shows a process flow chart of preparing non-PGM catalyst using porous polymer materials as the precursor;
FIG. 2 shows a reaction scheme of synthesis of a porous polymer, PBPY2;
FIGS. 3A-3D show four different reaction schemes of synthesis of a porous polymer, PBPY4, PBPY5, PBPY6, PBPY7;
FIG. 4 shows selected monomers (I, II and III) which are preferably used for preparing porous polymers as the catalyst precursors;
FIG. 5 shows polarization curves from a ring rotating disk electrode (RRDE) study of PBPY-2 treated at 500° C. (solid circle), 600° C. (hollow circle), 700° C. (solid triangle), 800° C. (hollow triangle), and 900° C. (solid square) and with a rotating speed=1600 rpm, and catalyst loading=800 μg/cm 2 ;
FIG. 6 shows electron transfers for PBPY-2 treated under Ar at 500° C., solid circles; 600° C., hollow circles; 700° C., solid triangles; 800° C., hollow triangles; 900° C., solid squares;
FIG. 7 shows ORR activity for PBPY2 treated at 700° C. with different cobalt contents of about 20% (solid circle) and 1.7% (hollow circle);
FIG. 8 shows RDE results for a Co-PBPY after heat-activation at 700° C. (solid circles) and RDE results for 700° C. heat activated sample, followed with immersion and washing with 0.5 M H2SO4 (hollow circles);
FIG. 9 shows RDE results for Co-PBPY at 700° C. (solid circles); Co-PBPY/cyanamide treated at 700° C. under Ar (hollow circles); and Co-PBPY/imidazole treated at 700° C. under Ar (solid triangles);
FIG. 10 shows ORR activity for a Co-PBPY sample that was heat treated at 700° C. under Argon (solid circle), in comparison with a sample followed by another heat treatment under NH3 at 600° C. for one hour (open circle);
FIG. 11A shows XPS system results for carbon C1s for a sample treated for Example 8 activated at 500° C.; and also shows the same starting sample activated at 700° C.; FIG. 11B shows the XPS system results for nitrogen N1 s as for conditions of FIG. 11A ;
FIG. 12A ( 1 ) shows a sample from Example 9 examined by transmission electron microscopy (TEM) with sample activation at 500° C. and magnification defined by the 50 nm scale bar and FIG. 12A ( 2 ) a higher magnified version of 12 A( 1 ); FIG. 12B ( 1 ) is also the Example 9 material but activated at 700° C. with the indicated magnification for the TEM image and FIG. 12B ( 2 ) a higher magnified version of 12 B( 1 );
FIG. 13 shows a reaction scheme for synthesis of a porous polymer, Fe-Por-1, prepared according to Example 10;
FIG. 14 shows reaction schemes for the synthesis of porous polymers, Fe-Por-2, Fe-Por-3, Fe/Co-Por-2, Fe/Co-Por-3 prepared according to Example 11;
FIG. 15 shows polarization curves from a ring rotating disk electrode (RRDE) study of Fe-Por-1 without heat treatment, with heat treatment at 600° C. and 700° C. according to Example 12;
FIG. 16 shows the number of electron transferred as a function of polarization potential for Fe-Por-1 without heat treatment, with heat treatment at 600° C. and 700° C. according to Example 12;
FIG. 17 shows RRDE results for Fe-Por-1 with heat treatment at 700° C., 800° C., 900° C. and 1000° C. according to Example 12;
FIG. 18 shows RRDE results for Fe/Co-Por-1 after heat treatment at 700° C. and 900° C. according to Example 12; and
FIG. 19 shows the power density for a fuel cell containing a cathode catalyst of Fe-Por-1 after heat treatment at 1000° C. according to Example 13.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In a fuel cell, a cathodic oxygen reduction reaction, such as that described by Equation 2 hereinbefore, typically occurs at the surface of platinum in the electrocatalyst. Molecular oxygen is first adsorbed on the Pt active site and is subsequently converted to water by capturing four electrons and reacting with four protons.
In one embodiment, electroactive material or non-PGM electrocatalysts are produced using thermally treated, transition metal-containing porous polymers. The new materials are prepared according to the process flow chart in FIG. 1 , and can be described by the following steps: I) preparing the porous polymer through cross-linking monomers with stereo-contorted cores and functional groups such as nitrogen-containing groups that can serve as coordination sites. The cross-linking reaction could be cyclization or coupling of the terminal functional groups of the monomers: such as trimerization of ethynyl groups catalyzed by transition metal catalysts (dicobalt octacarbonyl, etc), trimerization of cyano groups catalyzed by trifluoromethylsulfonic acid or lewis acid (zinc chloride, etc); oxidative coupling of thiophenyl groups promoted by chemical oxidant FeCl 3 or by constant voltage bias, homocoupling of arylbromide or ethynyl groups catalyzed by nickel catalyst or palladium catalyst; condensation coupling of arylamine with ketone, aldehyde, or anhydride; and cross-linking through Friedel Crafts reaction.
Not limited by the scientific hypothesis, the monomers with stereo-contorted core are used to produce micropore, mesopore and high surface area whereas the monomers with N-, O- or S-containing functional groups are used to produce ligation sites for transition metal inside of the porous polymers. The monomers with stereo contorted core refer to those molecules with functional groups that produce cross-linking at orthogonal, tetrahedral, or any three-dimensional direction. Non-limiting examples of such functional groups include spirobifluorene, and tetraphenyl methane. The cross-linking reaction may also be performed in the absence of the stereo-contorted core. In the absence of the stereo-contorted core, the high surface area and porosity polymers may be produced through hindrance of the functional groups in the monomers when they are cross-linked together. For example, porphyrin monomers contain macrocyclic ring with large molecular dimensions. Such monomers possess stereo-hindrance when they are cross-linked by coupling reactions.
The polymerization process, therefore, produces high surface area and high porosity polymers with transition metal ligation site uniformly distributed throughout. Once the polymerization process is completed, the polymer is filtered and separated from the solvent and ready for the next step; II) the porous polymers prepared in step I) could already contain transition metals if monomers coordinated with transition metals (such as Co, Fe, Ni, etc) are used for the cross-linking polymerization, and can be further infused with transition metals such as Co, Fe, Ni, Cr, Cu, Mn, Ta, W and other conventional transition metals. Such metals can be added in the porous polymer using their respective organometallic compounds or inorganic salts. These compounds can be added through liquid phase or gas phase processes, such as a conventional wet-incipient approach, impregnation, chemical vapor deposition, and other methods. The added metals will either be coordinated into the ligation sites through chemical reaction or entrapped into the micropores inside of the polymers.
In addition to metals, nitrogen-containing organic compounds can also be added into the polymers through liquid, solution or gaseous methodologies. While not being limited by the scientific hypothesis, the addition of the organic compounds are expected to coordinate with metal ion inside of the polymers that will promote the formation of the electrocatalytic active sites during the next process step of thermal treatment; III) the processed polymer materials produced in step II) will be thermally treated in the inert atmosphere such as under Ar or N 2 or reactive environment under nitrogen containing gas such as NH 3 , pyridine or acetonitrile at the elevated temperature. The polymers will be converted to carbonaceous material decorated with the catalytic center after this process; IV) a post treatment can be optionally added after the thermal treatment to further improve the electrocatalytic activity. The post treatment method can include one or more approaches such as acid treating, ball milling or a secondary heat-treating either in inert atmosphere or nitrogen containing gases such as NH 3 , pyridine or acetonitrile, etc.
The electrode catalysts prepared by the methods of the invention may exhibit several advantages over that of prior art in the following aspects: a) high surface area—porous polymers are generally a high surface area material. Even after the high temperature treatment, a substantial fraction of the surface area can be maintained at the pre-treatment level or even enhanced. High surface area enables the exposure of catalytic active sites to the reactants which is important for fuel cell applications; b) high active site density—porous polymers are synthesized through cross-linking of stereo-contorted core and monomers with ligation sites for transition metals. Such ligation sites are distributed in high density inside of porous polymer framework for interaction with transition metals. High transition metal to carbon and nitrogen ratio therefore provides a higher number of the catalyst site per unit volume when porous polymers are used as initial material for non-PGM catalyst preparation. Such approach does not require mixing with other support materials such as carbon which often dilute the volumetric density of the active site; c) uniform catalyst site distribution—porous polymers have well defined metal coordination sites evenly distributed throughout the porous structure, which will lead to uniformly distributed catalyst sites after the heat-treatment process. Such approach also offers better homogeneity than that mixed with support materials such as carbon which do not contain catalytic active sites by themselves; d) ease of chemical exchange—often the catalytic activity of the material can be further enhanced when thermally treated in the presence of another chemicals such as a precursor of another transition metal or another N-containing organic compound. Porous polymers have a high fraction of pores with uniformly distributed cavity. Such void spaces can be used to accommodate different precursors, such as the transition metal compounds or N-containing organic compounds through an efficient chemical processes, such as solvent exchange. The added chemicals are also in immediate proximity of the transition metal for effective formation of the catalytic active sites during the heat-treatment process.
A preferred process of preparing non-PGM electrode catalysts using porous polymers as precursors includes the following steps:
Step I—Preparing Porous Polymers.
Porous polymers can be prepared by cross-linking one or two types of monomers functionalized with appropriate functional groups, such as ethynyl, cyano, thiophenyl, fluoro/bromo/iodo, amino, ketone, aldehyde, carboxylic anhydride, chloromethyl, and etc. The cross-linking reactions to obtain porous polymers include but not limited to: trimerization of ethynyl groups catalyzed by transition metal catalysts (dicobalt octacarbonyl, etc), trimerization of cyano groups catalyzed by trifluoromethylsulfonic acid or lewis acid (zinc chloride, etc); oxidative coupling of thiophenyl groups promoted by chemical oxidant FeCl 3 or by constant voltage bias, homocoupling of arylbromide or ethynyl groups catalyzed by nickel catalyst or palladium catalyst; condensation coupling of arylamine with ketone, aldehyde, or anhydride; and Friedel Crafts reaction between chloromethyl and phenyl groups. In a preferred embodiment of the current invention, one of the monomers contains nitrogen coordination sites for incorporating transition metals, the other monomer has stereo-contorted structure, such as spirobifluorene, tetraphenylmethane and triphenylamine, for maintaining the porous structure of the resulting polymer.
For example, ethynyl functionalized bipyridine and spirobifluorene could form porous polymers through trimerization of the ethynyl groups or homocoupling of the same ethynyl groups, as is shown by reaction scheme in FIG. 2 . If the terminal functional groups of bipyridine and spirobifluorene are changed to amine or aldehyde groups, they could form porous polymer through condensation coupling reaction, as is shown by Equation 1 in FIG. 3A ; if the terminal functional groups of bipyridine and spirobifluorene are changed to bromo groups, they could form porous polymers through homocoupling reaction, as is shown by Equation 2 in FIG. 3B ; if the terminal functional groups of bipyridine and spirobifluorene are changed to chloromethyl groups, they could form porous polymers through Friedel Crafts alkylation reaction, as is shown by Equation 3 in FIG. 3C ; if the terminal functional groups of bipyridine and spirobifluorene are changed to cyano groups, they could form porous polymers through trimerization of the cyano groups, as is shown by Equation 4 in FIG. 3D . In another preferred embodiment, one monomer can be used for self-cross-linking if it combines both nitrogen-containing coordination site and stereo-contorted structure in one. The stereo-contorted structure could also be attributed to the stereo-hindrance of the monomer during the cross-linking reaction. An example is polymerization of thiophenyl functionalized porphyrin to form porous polymer with N4 coordination site for transition metals.
Examples of these three types of monomers (types I, II and III) are illustrated by FIG. 4 . Type I are monomers with nitrogen-containing ligation sites for transition metals, such as 4,4′-diethynyl-2,2′-bipyridine (M1), 5,5′-diethynyl-2,2′-bipyrimidine (M2), and 3,8-diethynyl-1,10-phenanthroline (M3). Type II are monomers with stereo-contorted core, such as 2,2′,7,7′-tetraethynyl-9,9′-spirobifluorene (M4), tetrakis(4-ethynylphenyl)methane (M5). Type III are thiophenyl functionalized porphyrin and arylbromide functionalized porphyrins. For one preferred form of the current invention, one monomer from Type I and another monomer from Type II are selected for cross-linking reaction. An example include one monomer containing sipirobifluorene (M4) and another monomer containing bipyridine (M1) in 1 to 2 ratio were dissolved in organic solvent to obtain a clear solution; and the concentration of each monomer ranges from 0.01 mol/L to 0.05 mol/L; metal complexes in equal amount of bipyridine were added to coordinate with the monomer containing bipyridine. Examples of the metal complexes for coordination include, but are not limited to Co 2 (CO) 8 , Co(hfac) 2 , Fe(hfac) 2 , Ni(hfac) 2 , where hfac represents hexafluoroacetylacetonate.
In some embodiments, the transition metal catalyst, such as Co 2 (CO) 8 , is added, and the reaction mixture may be stirred well before refluxing for 1.5 hours. In one embodiment, only one monomer from Type III may be used for polymer preparation. An example is a porphyrin functionalized with thiophenyl groups (M6) or arylbromide groups (M7 and M8) may be incorporated with a metal ion, such as Fe (II), Co(II), Ni(II), Mn(II), Cu(II), Zn(II), etc. The metalloporphyrin may then be dissolved in appropriate solvent, such as chloroform, acetonitrile, or dimethylformamide. Thiophenyl functionalized porphyrin monomer solution in chloroform or acetonitrile was prepared by adding the monomer to a suspension of FeCl 3 in chloroform or acetonitrile dropwise. Then, the reaction mixture can then be stirred for 12 hours; in the case of arylbromide functionalized porphyrin monomers, to their solution in dimethylformamide was added bis(1,5-cycloctadiene)nickel(0), bipyridine and 1,5-cyclooctadienem the reaction mixture was then heated at 80° C. for 24 to 72 hours. The polymers may be collected via filtration after washing with methanol and/or hydrochloric acid.
Step II—Addition of Transition Metals and Organic Compounds.
The porous polymers generally have high porosity with narrowly distributed pore sizes in nanometer scale. The pores in these polymers can be used to entrap additional transition metals and/or nitrogen-containing organic compounds that can promote formation of catalytic active sites. Various methods, such as post-coordination, adsorption, chemical evaporation, can be used to add precursors containing transition metals and/or organic compounds into the porous polymers. For example, to add transition metal complexes into the polymer, a solution of metal complexes in ethanol was refluxed with fine powder of the polymer that contains bipyridines or porphyrin for 12 hours or so, metal complexes will chemically coordinate with the bipyridine sites and this is the so called post-coordination method. To add transition metals and/or organic compounds to the polymers without free coordination sites, a solution of the transition metals and/or organic compounds in ethanol was gently refluxed with a suspension of the porous polymers in an open vial until the solvent dried out, most of the transition metals and/or organic compound will be adsorbed by the porous polymer. In this embodiment, transition metals that can be used include, but are not limited to, ferrocene, tantalum chloride, Prussian blue, iron nitrate, cobalt nitrate, iron acetate or cobalt acetate. Nitrogen-containing organic compounds used in this embodiment include, but are not limited to, imidazole, caynamide, dimethylformamide, dimethylacetamide, pyridine or 1,10-phenanthroline. After the addition of chemical moieties, the porous polymer materials can be subjected to the thermal conversion as described in the Step III.
Step III—Thermal Activation of Processed Porous Polymers.
During this step, the porous polymer materials prepared from Step II will be subjected to a high temperature treatment. Such treatment will partially decompose and carbonize the polymers. This treatment serves two purposes: a) forming active site through the reaction between ligated metal center and the polymer framework, and optionally with added organic materials through pyrolysis; and b) improving the electron conductivity of the framework materials by carbonizing the polymer framework so that the charge can be more effectively transferred to and from the catalytic active site during the electrochemical reaction. The thermal conversion of the polymer material is generally conducted in a controlled environment, such as a sealed reactor or a flow reactor surrounded by heating element. In a preferred embodiment, the treatment is carried out inside of a tubular reactor under the constant flow of carrier gas surrounded by temperature controlled furnace. The thermal conversion temperature typically ranges from 400° C. to 1100° C. In a more preferred embodiment, the temperature ranges from about 600° C. to 1000° C. In an even more preferred embodiment, the temperature ranges from about 700° C. to 800° C. The time sample under the thermal conversion temperature should also be controlled. According to the present embodiment of invention, the thermal treatment time should be controlled between 30 minutes to 3 hours. In the more preferred embodiment, the time under the treatment of temperature should be 30 minutes to 120 minutes.
Another condition for thermal treatment should be carefully controlled is the chemical composition of the carrier gas. In one embodiment of the invention, the carrier gas should be inert gases such as Ar, He, or nitrogen. In another embodiment of the invention, the carrier gas should be reductive and containing nitrogen. The examples of such reducing carrier gas include, but not limited to, NH 3 , pyridine or acetonitrile.
Step IV—Post Treatment.
After the thermal conversion process in step III, the material can be processed through a post-treatment step to further improve the electrocatalytic activity. According to one embodiment of current invention, the post-treatment can be accomplished through acid washing. A variety of inorganic acids can be used to dissolve the excess amount metals in the material from Step III by simply immersing the thermally treated porous polymer in the acid solution. The acid for this application include hydrochloric acid, sulfuric acid, nitrate acid, and other acid known to dissolve metals. In one embodiment the concentration of the acid can be at lower concentration in the range of about 0.1 molar to undiluted concentration. In a preferred embodiment, the concentration of the acid ranges from about 0.5 molar to 2 molar. The acid treatment temperature can range from the ambient to as high as about 80° C. The acid treatment time ranges from about 0.5 hour to 72 hours. According to another embodiment of the invention, the porous material obtained after Step III before or after acid wash in Step IV can be further treated under elevated temperature in an inert gas flow or in a nitrogen-containing gas flow under the similar temperature and carrier gas described in Step III. Not limited by the scientific hypothesis, such a second thermal treatment after acid washing can further improve the electrocatalytic activity by restructuring the non-active to active site and by adding more active site through incorporating more nitrogen into carbonaceous framework. Examples of such reducing carrier gas include, but are not limited to, NH 3 , pyridine or acetonitrile.
The process of preparing electrocatalyst according to the embodiments of the current invention can be further elucidated by the following non-limiting examples:
Example 1
FIG. 2 shows the synthetic approach to preparing polymer PBPY2 which contains bipyridine coordinate site for incorporating transition metals into the polymer. Cobalt carbonyl, which served as both coordination metal complex and catalyst of the trimerization reaction, was stirred well with a solution of compounds 2,2′,7,7′-tetraethynyl-9,9′-spirobifluorene and 5,5′-diethynyl-2,2′-bipyridine in anhydrous dioxane, and the mixture was then brought to reflux to initiate the polymerization reaction. The product PBPY2 is a porous polymer with surface area in the range of 250-400 m 2 /g. Elemental analysis showed that the polymer contains about 8 H 2 O and 1.48 Co 2 (CO) 8 per repeating unit (C 61 H 32 N 4 ). TGA (Thermal Gravimetric Analysis) of PBPY2 showed that all of the 8 H 2 O loses around 100° C. (corresponding to 10% weight lost), while all of the carbonyl groups lose around 300° C. (corresponding to 32.3% weight lost). More detailed preparations of chemicals and polymer are described in the following:
Compound 1 (5,5′-Bis(trimethylsilylethynyl)-2,2′-bipyridine)
in FIG. 1 was synthesized according to conventional reported methods.
Compound 2 (5,5′-Diethynyl-2,2′-bipyridine)
5,5′-Bis(trimethylsilylethynyl)-2,2′-bipyridine (1.65 g, 4.73 mmol) was dissolved in 20 ml of methanol and 30 ml of THF, KF (0.70 g, 12.0 mmol) was added at room temperature, and the mixture was stirred for 6 hours. Solvent was removed using a rotary evaporator, and the residue was dissolved in dichloromethane and filtered through a pad of basic alumina (activity IV), the filtrate was concentrated and the solid was recrystallized from chloroform/ethanol to give the product 0.87 g (90% yield). 1 H NMR (CDCl3): 3.31 (s, 2H), 7.90 (dd, J=8.0 Hz, 2.0 Hz, 2H), 8.39 (d, J=8.0 Hz, 2H), 8.77 (d, J=2.0 Hz, 2H).
Compound 3 (2,2′,7,7′-tetraethynyl-9,9′-spirobifluorene)
was synthesized according to the following procedure; a) Fe powder (0.075 g, 1.33 mmol) was added to a solution of 9,9′-spirobifluorene (7.0 g, 22.1 mmol) in 33 mL of chloroform, the mixture was then cooled to 0° C., then neat bromine (4.9 mL, 95.03 mmol) was added slowly via a syringe. The mixture was stirred at 0° C. for 1 h, then warm to room temperature, continue stirring for another 3-5 h, and the evolved HBr gas was exported to a NaOH solution. The reaction mixture was then poured into saturated Na 2 CO 3 solution to remove the excess Br 2 , and extracted with CH 2 Cl 2 twice. The combined organic phase was washed with brine once, separated and dried over anhydrous Na 2 SO 4 . After removing the solvent, white solid product 2,2′,7,7′-tetrabromo-9,9′-spirobifluorene (14.0 g, 99% yield) was obtained in its pure form. Further purification could be done by crystallization from CHCl 3 /EtOH mixture. 1 H NMR: δ (ppm): 6.82 (d, J=1.6 Hz, 4H, Ar—H), 7.54 (dd, J=1.8, 8.2 Hz, 4H, Ar—H), 7.68 (d, J=8.2 Hz, 4H, Ar—H). b) The above product 2,2′,7,7′-tetrabromo-9,9′-spirobifluorene (3.0 g, 4.75 mmol), PdCl 2 (PPh 3 ) 2 (0.26 g, 0.37 mmol), CuI (0.036 g, 0.19 mmol) and PPh 3 (0.2 g, 0.76 mmol) were placed in a round bottom flask, anhydrous i-Pr 2 NH (50 mL) and trimethylsilyl acetylene (3.24 mL, 22.8 mmol) were added via a syringe. The reaction mixture was brought to reflux overnight then cooled down to room temperature. Solvent was removed in vacuum, and CHCl 3 was added to dissolve the residue, and filtered through a pad of celite. The filtrate was washed with dilute Na 2 EDTA solution, and then dried over anhydrous Na 2 SO 4 , the solution was concentrated and ethanol was added to obtain white solid product 2,2′,7,7′-tetra(trimethylsilyl acetyl)-9,9′-spirobifluorene (3.0 g, 90% yield) in its pure form. 1 H NMR: δ (ppm): 0.16 (s, 36H, CH 3 ), 6.77 (d, J=0.8 Hz, 4H, Ar—H), 7.49 (dd, J=1.4, 7.9 Hz, 4H, Ar—H), 7.74 (d, J=7.9 Hz, 4H, Ar—H). 13 C NMR: δ (ppm): 0.4, 96.1, 106.0, 121.4, 124.0, 128.9, 133.4, 142.5, 149.2. c) NaOH (0.286 g, 7.1 mmol) was dissolved in 5 mL CH 3 OH, then add to a solution of 2,2′,7,7′-tetra(trimethylsilyl acetyl)-9,9′-spirobifluorene (0.5 g, 0.71 mmol) in 20 ml CH 2 Cl 2 , then stirred for 6 h at room temperature. The reaction mixture was washed with water, and the aqueous phase was extracted with CH 2 Cl 2 once, combined organic phase was washed with brine, and then dried over anhydrous Na 2 SO 4 . The solution was concentrated and ethanol was added to the solution. Light yellow solid product 2,2′,7,7′-tetraethynyl-9,9′-spirobifluorene (0.273 g, 95% yield) was obtained in its pure form. 1 H NMR: 6 (ppm): 3.01 (s, 4H, C≡CH), 6.866 (d, J=0.8 Hz, 4H, Ar—H), 7.54 (dd, J=1.4, 7.9 Hz, 4H, Ar—H), 7.80 (d, J=7.9 Hz, 4H, Ar—H).
Synthesis of Cobalt Doped Polymer Co-PBPY
2,2′,7,7′-tetraethynyl-9,9′-spirobifluorene (0.484 g, 1.17 mmol) and 5,5′-Diethynyl-2,2′-bipyridine (0.480 g, 2.34 mmol) were added into a flame-dried round bottom flask, anhydrous dioxane 20 mL was added via a syringe, the mixture was stirred to get clear light yellow solution. Co 2 (CO) 8 (0.594 g, 1.736 mmol) was added under protection of N 2 . The reaction mixture was stirred at room temperature for 20 minutes. The flask was then placed into oil bath that was pre-heated to 115° C. The brown solution started to solidify after about 5 minutes. The reaction mixture was heated for another hour, and lifted above the oil bath to cool to room temperature. The brown solid was crushed to fine particles using a spatula, then washed with dioxane, and filtered to collect the solid. After air-drying for an hour, the solid was dried in vacuum oven at 100° C. for 1 day. About 1.56 g (100%) of brown solid was obtained. Elemental Analysis: Calculated for {C 61 H 32 N 4 [Co 2 (CO) 8 ] 1.48 }x: C, 65.93; H, 2.43; Co, 13.15; N, 4.22. Found: C, 60.26; H, 3.20; Co, 10.91; N, 3.60; corresponding to formula {C 61 H 32 N 4 [Co 2 (CO) 8 ] 1.48 (H 2 O) 8 }x, suggesting that the polymer contains 8 H 2 O per repeating unit.
Example 2
The cobalt-containing polymer Co-PBPY prepared according to Example 1 was heat treated at temperatures ranging between about 500 and 900° C. in the flowing argon for 60 minutes inside of a quartz reactor. The sample obtained after heat treatment was used to prepare the ink for the electrochemical characterization experiments. The ink containing the Co-based electrocatalysts was prepared using a 3:7 Nafion ionomer to Catalyst ratio, dissolved in 5 wt % Nafion® ionomer and methanol. The solution obtained was magnetic stirred for at least a week before testing. The ink thus prepared was applied to a glassy carbon electrode in a rotating disk electrode setup of CHI760D Electrochemical Workstation. Cyclic voltammograms in argon and oxygen gases were recorded at a rotation speed of 1600 rpm and a scan rate of 10 mV/s. The argon background is subtracted from the oxygen polarization curves, and the corrected current densities are plotted vs. standard hydrogen electrode (SHE) potential. The onset potential for ORR is defined as the voltage value at which point the polarization current measured in the oxygen saturated electrolyte starts to deviate from the background value measured with argon purged electrolyte. FIG. 5 shows the impact of the different treatment temperature on the ORR activity of the Co-PBPY material. The onset potential increases as the treatment temperature increases, reaching a maximum at 700° C. with the onset potential reaching a maximum value of 0.78 V. The Brunauer, Emmett, Teller (BET) surface area of the fresh sample was around 210 m 2 /g, and increased to around 550 m 2 /g after pyrolysis at 700° C.
Example 3
A desirable characteristic of a non-PGM catalyst is the ability to reduce oxygen directly to water via the four electron transfer mechanism. Rotating ring disk electrode (RRDE) experiments give the number of electrons transferred during oxygen reduction, as a proportion between the disk current and the ring current, according to:
n
=
4
I
d
I
d
+
I
r
/
N
Where n is the number of electrons transferred or selectivity, I d the disk current, I r , the ring current and N the collection efficiency of the electrode. FIG. 6 shows the number of electron transfer as the function of electrode potential measured for the catalyst sample prepared by heat treated porous polymer at 700° C. according to Example 2.
Example 4
A polymer prepared according to the Example 1 was washed in concentrated HCl to reduce the Co content to about 1.2%. The acid washed sample was further thermally treated at 700° C. in flowing argon according to the step described in Example 2. The catalyst ink was subsequently prepared and tested according to the procedure described in Example 2. FIG. 7 compares the ORR activity of this catalyst sample with that prepared 700° C. without acid pre-washing. No significant difference was observed in the catalytic performance despite the Co content being much lower in the current example.
Example 5
After the Co-PBPY is pyrolyzed, additional chemical treatments can lead to improved catalytic activity. For example, electrocatalytic improvement was observed when the Co-PBPY, heat treated at 700° C., was acid leached in 0.5 M H 2 SO 4 . The acid leach can wash the excess metal away, exposing hidden catalytic sites to the ORR reaction. It also helps to sulfonate and/or oxidize the carbonaceous framework, making it easier to interact with Nafion ionomer. FIG. 8 shows both current density and half-wave potential improved after acid leaching of treated Co-PBPY, possibly due to improved mass transfer due to better exposure of more catalyst site through removal of excess metallic cobalt.
Example 6
Introducing pyridinic or pyrolic nitrogen to the sample can form additional catalytic sites when the nitrogen coordinates to excess cobalt complexes. The pyridinic or pyrolic nitrogen can be added by impregnating N-containing organic compound, such as imidazole or cyanamide, to the fresh polymer sample (as prepared Co-PBPY polymer), followed by the heat-treatment under Ar as described by Example 2. FIG. 9 shows influence on catalytic performance by adding imidazole and cyanamide to Co-PBPY polymer before heat treatment. Both ORR onset potentials and half-wave potentials were improved through introducing nitrogen-containing organic compound to the sample before the activation step.
Example 7
Another way to introduce nitrogen to the catalyst sample is through post-treating carbonized polymer with N-containing compound under elevated temperature. FIG. 9 shows the ORR activity for a Co-PBPY sample that was heat treated at 700° C. under Argon followed by another heat treatment under NH 3 at 600° C. for one hour. RDE experiment showed improved current density over that of the sample without the ammonia treatment.
Example 8
The thermally treated samples prepared according to the method in Example 4 were studied by X-ray photoelectron spectroscopic method (XPS) in order to understand the catalytic active site structural changes during the thermal activation. Shown in FIGS. 11A and 11B are XPS spectra of carbon C1s and nitrogen N1s for the sample activated at 500° C. and 700° C., respectively. As demonstrated by Example 4, the precursor converts from polymer to catalyst at these temperatures. FIGS. 11A and 11B clearly showed the change in the electronic structures of both carbon and nitrogen, from molecular moiety inside of a polymer to a carbonaceous material during the transition from polymer to electrocatalyst.
Example 9
The thermally treated samples prepared according to the method in Example 4 were also studied by the transmission electron microscopy (TEM) method. Shown in FIGS. 12A ( 1 )- 12 B( 2 ) are TEM images of the catalyst treated at 500 C and 700° C. During the thermal treatment, cobalt will catalyze the polymeric moieties it coordinated with to convert them to the catalyst active site. Simultaneously, some of the cobalt ions will be reduced to metallic Co.
Example 10
Porous polymers Fe-Por-1 and Fe/Co-Por-1 were prepared according to reaction scheme depicted in FIG. 13 . As shown in FIG. 13 , these porous polymers contain porphyrin coordination sites for incorporating transition metals into the polymer. The porphyrin monomers were first doped with Fe 2+ or Co 2+ . Then, the metal-containing porphyrin monomers were polymerized by an oxidative coupling polymerization reaction. If only Fe-doped porphyrin monomer was used in the polymerization, Fe-Por-1 was obtained; if a mixture of Fe-doped and Co-doped porphyrin monomers were used in the polymerization, Fe/Co-Por-1 was obtained. The synthesized polymers are highly porous materials with surface area in the range of 1200-1700 m 2 /g. Elemental analysis of Fe-Por-1 showed that 2.1% of Fe by weight was retained in the polymer, corresponding to 50% of the porphyrin rings were still coordinated with Fe ions. Detailed descriptions of the procedure for synthesis of the porous polymers are provided below.
Fe(II)—5,10,15,20-Tetrakis(3,5-dithiophen-2-ylphenyl)-porphyrin (Fe-TTPP)
Porphyrin TTPP (0.968 g, 0.726 mmol) was dissolved in 60 cm 3 DMF. FeCl 2 .4H 2 O (1.45 g, 7.26 mmol) was added to this mixture and boiled for 1 hour. The reaction mixture was then cooled down to room temperature, diluted with CH 2 Cl 2 , and filtered. The filtered mixture was washed with brine and the organic phase was collected and dried over NaSO 4 . After filtration, the solvent was removed to yield the Fe-TPPP. The Fe-TTPP was chromatographed on silica using a Hexane/CH 2 Cl 2 (1:1) solvent mixture as the eluent and produced 0.62 g (64%) yield. Mass spectroscopy results obtained were: CI-MS: Calcd, 1325.5. found (M+1) + , 1326.1. UV/vis (λ max , nm CH 2 Cl 2 ×10 5 cm −1 M −1 ) 285.5 (1.16), 416.5 (1.20), 573.0 (0.121), 612.0 (0.07).
Co(II)—5,10,15,20-Tetrakis(3,5-dithiophen-2-ylphenyl)-porphyrin (Co-TTPP)
Porphyrin TTPP (0.23 g, 0.172 mmol) was dissolved in 25 cm 3 DMF. Co(OAc) 2 .4H 2 O (0.215 g, 0.86 mmol) was added to this mixture and heated at 100° C. for 4 hour. The reaction mixture was then cooled to room temperature, diluted with CH 2 Cl 2 , and filtered. The filtered mixture was washed with brine and the organic phase was collected and dried over NaSO 4 . After filtration, the solvent was removed to yield Co-TTPP. The Co-TTPP was chromatographed on silica using a Hexane/CH 2 Cl 2 /ethyl acetate (6:3:1) solvent mixture as the eluent and produced 0.12 g (53%) yield. Mass spectroscopy results obtained were: Calcd, 1328.6. found (M + ) 1328.
Fe-Por-1
Anhydrous FeCl 3 (0.8 g, 5 mmol) was charged into a round-bottom flask. 10 ml of anhydrous CHCl 3 was added and stirred to make a suspension solution. Then a solution of Fe-TTPP (0.225 g, 0.17 mmol) in 20 ml of CHCl 3 was added dropwise at room temperature. The resulting mixture was stirred at room temperature for about 16 hours. 200 ml of MeOH was added to the above mixture and stirred for another hour. The precipitate was collected by filtration and washed with MeOH. The precipitate was stirred into 100 mL of CHCl 3 for 2 hours, and then filtered. The precipitate was dried in a vacuum oven at 90° C. overnight. The yield for Fe-Por-1 was about 100%.
Fe/Co-Por-1
Anhydrous FeCl 3 (0.8 g, 5 mmol) was charged into a round-bottom flask. 10 ml of anhydrous CHCl 3 was added and stirred to make a suspension solution. A solution of Fe-TTPP (0.11 g, 0.083 mmol) and Co-TTPP (0.11 g, 0.083 mmol) in 20 ml of CHCl 3 was added dropwise at room temperature. The resulting mixture was stirred at room temperature for about 16 hours. 200 ml of MeOH was added to the above mixture and stirred for another hour. The precipitate was collected by filtration and washed with MeOH. The precipitate was then stirred into 100 mL CHCl 3 for 2 hours, and filtered. The solid product was dried in a vacuum oven at 90° C. overnight. The yield for Fe/Co-Por-1 was about 100%.
Example 11
Porous polymers Fe-Por-2, Fe/Co-Por-2, Fe-Por-3, and Fe/Co-Por-3 were prepared according to reaction schemes in FIG. 14 . First, bromo-functionalized porphyrin monomers were doped with Fe 2+ or Co 2+ . The bromo-functionalized porphyrin monomers are Fe-TPPP, Co-TPPP, Fe-TPP or Co-TPP. Then, the metal-containing porphyrin monomers were polymerized by an homocoupling reaction using nickel catalyst. The metal-doped bromo-functionalized porphyrin was prepared using the same procedure as described in Example 10. If only Fe-doped porphyrin monomers are polymerized, Fe-Por-2 and Fe-Por-3 is obtained; when a mixture of Fe-doped and Co-doped porphyrin monomers are polymerized, Fe/Co-Por-2 and Fe/Co-Por-3 is obtained. Detailed descriptions of the procedure for synthesis of the porous polymers are provided below.
Fe-Por-2
Fe-TPPP, bis(1,5-cyclooctadiene)nickel(0), bipyridine and 1,5-cyclooctadiene were charged into a round-bottom flask under argon, Anhydrous DMF was added via a syringe. The reaction mixture was then shielded from light and heated to 80° C. using a heating mantle for 3 days. After the reaction mixture was cooled to room temperature, dilute hydrochloric acid was added to decompose the nickel catalyst. The precipitate was collected by filtration and further washed sequentially with water, methanol, and CHCl 3 . The product, Fe-Por-2 was dried in a vacuum oven at 90° C. overnight.
Fe/Co-Por-2
Equal molar solutions of Fe-TPPP and Co-TPPP, bis(1,5-cyclooctadiene)nickel(0), bipyridine and 1,5-cyclooctadiene were charged into a round-bottom flask under argon. Anhydrous DMF was added via a syringe. The reaction mixture was shielded from light and heated to 80° C. using a heating mantle for 3 days. After the reaction mixture was cooled to room temperature, dilute hydrochloric acid was added to decompose the nickel catalyst. The precipitate was then collected by filtration and further washed sequentially with water, methanol, and CHCl 3 . The product, Fe/Co-Por-2 was dried in vacuum oven at 90° C. overnight.
Fe-Por-3
was prepared from Fe-TPP using the same procedure as used to prepare Fe-Por-2.
Fe/Co-Por-3
was prepared from equal molar solutions of Fe-TPP and Co-TPP using the same procedure as used to prepare Fe/Co-Por-2.
Example 12
The porous polymer, Fe-Por-1, prepared according to Example 10 was heat treated at temperatures ranging between 600° C. and 1000° C. Fe-Por-1 is placed in a quartz reactor and heated to a set temperature under flowing nitrogen for 60 to 120 minutes. Ink was prepared using Fe-Por-1 with and without heat treatment and cyclic voltammomgram measurement were taken in argon and oxygen gases according to the procedure described in Example 2. FIG. 15 shows polarization curves from the ring rotating disk electrode (RRDE) of Fe-Por-1 without heat treatment (depicted by squares), Fe-Por-1 heat treated at 600° C. (depicted by circles) and at 700° C. (depicted by triangles). Here, the onset potential for Fe-Por-1 without heat treatment was not clearly observable; for Fe-Por-1 heat treated at 600° C. was about 0.68V; for Fe-Por-1 heat treated at 700° C. was about 0.91V.
Based on the RRDE curves for Fe-Por-1, the number of electrons at each potential can be determined according to Example 3. FIG. 16 shows the number of electron transferred as the function of electrode potential measured for Fe-Por-1 without heat treatment (depicted in squares) and with heat treatment at 600° C. (depicted in circles) and 700° C. (depicted in triangles). The sample treated at 700° C. has the electron transfer number of nearly 4 from 0 up to 0.8 volt, indicating a near complete conversion of oxygen to water during ORR reaction, which is preferred, in one embodiment, because it minimize undesirable peroxide formation.
Further studies confirmed the effect of heat treatment temperature of Fe-Por-1 on the on-set potential, which is a measure of ORR activity of the material. The higher onset potential is preferred since it can be made into cathode catalyst in PEMFC with lower over potential and high fuel cell efficiency. FIG. 17 shows the polarization curves for Fe-Por-1 heat treated at 700° C. (depicted by squares), 800° C. (depicted by circles), 900° C. (depicted by triangles) and 1000° C. (depicted by stars). As shown in FIG. 17 , the onset potential increases as the heat treatment temperature increases from 600° C. to 700° C., and remains the same through up to 1000° C. The maximum onset potential obtained was 0.93 V vs. RHE. The Brunauer Emmett, Teller (BET) surface area of the Fe-Por-1 without heat treatment was measured to be around 1250 m 2 /g. The surface area of the Fe-Por-1 decreased to 760 m 2 /g after heat treatment at 700° C. indicating less than 40% loss of surface area as the result of conversion of organics to carbon during thermolysis. Such conversion is critical in improving electron conductivity to and from the active site. Over 60% retention of the surface area suggests that a majority of pores in polymer remains nearly unchanged.
The ORR activity of Fe/Co-Por-1 obtained according to Example 10 was heat treated at 700° C. and 900° C. was measured by RRDE curves shown in FIG. 18 . An onset potential of around 0.91 V vs. RHE was obtained for samples heated at these two temperatures.
Example 13
Fe-Por-1 was thermally treated at 1000° C. according to Example 12, and the resulting catalyst material was used as the cathode catalyst in a fuel cell. Commercial Pt/C was used as the anode catalyst. Loading of cathode catalyst was 4.0 mg/cm 2 , and the loading of anode catalyst was 0.25 mg Pt/cm 2 . The two electrodes were then hot pressed onto a Nafion membrane to get a membrane electrode assembly (MEA). A fuel cell was then prepared with the MEA. FIG. 19 shows the polarization curve and power density obtained with this fuel cell. The fuel cell has maximum power density of 0.7 W/cm 2 , which is approaching the performance of MEA prepared with Pt/C as the cathode catalyst
The subject invention described hereinbefore may exhibit numerous advantageous features, such as:
High active site density—without the need for additional carbon support which could dilute site density. The site density is limited only by polymer design at molecular level therefore high number of active site can be achieved. Uniform catalytic site distribution—the catalytic sites are pre-built homogenously through cross-linking reaction without the in-homogeneity introduced by mixing support material, such as mixing carbon with polymer, as taught by the prior arts. High surface area and pore size control—narrow pore structure is homogenously distributed throughout the polymer which will lead to uniform porosity and surface property throughout the catalyst after thermal activation. Generally the surface areas are substantially enhanced after the thermal activation. Flexibility of precursor design—a wide variety of monomers and polymerization reactions can be used to rationally design the catalyst precursor for further enhancing the catalytic activity. This provides high level of flexibility that cannot be achieved in conventional catalysts.
The foregoing description of embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the present invention. The embodiments were chosen and described in order to explain the principles of the present invention and its practical application to enable one skilled in the art to utilize the present invention in various embodiments, and with various modifications, as are suited to the particular use contemplated.
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A method of producing an electrocatalyst article using porous polymers. The method creates a porous polymer designed to receive transition metal groups disposed at ligation sites and activating the transition metals to form an electrocatalyst which can be used in a fuel cell. Electrocatalysts prepared by this method are also provided. A fuel cell which includes the electrocatalyst is also provided.
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