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FIELD OF THE INVENTION
The present invention relates to the field of electronics, and in particular to asynchronous, First-In-First-Out(FIFO) buffer circuits.
BACKGROUND
Typical electronic logic systems today use clocked Boolean binary logic circuits. Such binary circuits express two values as separate voltages on a single signal line, such as numeric values ZERO and ONE, or logical TRUE and FALSE. Most often, a ground voltage potential represents numeric ZERO or logic FALSE, and a second voltage (e.g., +5 volts) represents numeric ONE or logic TRUE. The most commonly used logic systems perform Boolean logic operations on binary signals, such as AND, OR, and NOT operations. A signal format that uses a single signal line to represent binary values for use with Boolean logic will be referred to here as "Boolean binary" format.
Clocked Boolean logic (CBL) circuits are Boolean logic circuits that use clock signals to regulate the timing of signal processing. For example, a clocked Boolean logic circuit might present input signals to a circuit on the rising edge of a clock, and latch the output of the circuit on the falling edge of the clock. Such use of a clock allows the input signals time to propagate through the circuit, and (if properly designed) ensures that the circuit outputs have settled to final values before sampling the result. Clocks tend be highly regulated to have a fixed frequency (and thus a fixed period), by deriving their periods from a crystal or other oscillator. If the clock period is shorter than signal propagation delay through the circuit, the output might not be valid at the sampling time, and potentially invalid data will be latched.
A First-In-First-Out(FIFO) buffer is a memory circuit characterized by the order in which data may be stored and recovered. Data may be read from a FIFO buffer only in the same order in which it was stored. For example, the first data read from a FIFO buffer is always the first data that was stored (hence the name "first-in-first-out"). A FIFO buffer can also be characterized by two size properties. The width (or "word size") of a FIFO buffer describes the amount of data that can be stored or read at one time. The depth describes the total amount of information that can be stored (often quoted as a number of words).
In clocked FIFO buffers, one or more clock signals regulate the timing of read and write operations, as well as internal operations. When a single clock is used, the input and output rates are identical, and data propagates through the buffer with a fixed delay. Internally, the clock signal regulates movement of data through a series of storage locations so that the contents of all storage locations advance simultaneously. If the clock rate exceeds the maximum operating speed of the internal circuits, an internal storage location might latch a value before receiving new data from a prior location. Furthermore, the circuit associated with a storage location could oscillate or become metastable.
Typically, internal circuitry is designed to operate at conservative clock speeds that allow some margin between the clock period and the worst case delays in the internal circuitry. Such margin avoids certain timing problems, but guarantees that many or all parts of the circuit operate at less than the maximum possible speed.
In other clocked FIFO buffers, separate read and write clocks regulate the writing and reading processes. The read and write clocks determine the read and write data rates, respectively, which may be different. Overflow may occur when an external circuit attempts to write data to a full buffer. Under flow may occur when an external circuit attempts to read data from an empty buffer.
It is relatively simple to build synchronous FIFO buffers for use between two external circuits if both external circuits use the same clock or synchronized clocks. However, FIFO buffers have proven relatively harder to design and control reliably for systems operating in two different and non-synchronous clock domains. Such a FIFO must accommodate (1) irregularities in the availability of data, and (2) differences in the basic clocking systems. Thus, in two-clock FIFO buffer design, the form of clock used within a FIFO and its control logic is an important factor that absorbs substantial design resources and time.
It is desirable to have a complete family of FIFO designs that are readily available, easily scale able, and do not suffer from timing problems or metastability. It would be possible to maintain a large library of commonly-used and tested FIFO designs for a wide variety of purpose. However, it would be nearly impossible to predict and account for all such uses. Therefore, a new (or modified) design would have to be produced for each application then rigorously tested.
SUMMARY OF THE INVENTION
The invention relates to asynchronous FIFO buffers in which data signals propagate inside the FIFO without regard to system clocks. The FIFO buffer operates at the maximum speed of the physical devices, yet can be easily modified.
The preferred FIFO buffer is particularly useful for interfacing two clocked systems whose clocks are not synchronous with one another. It may be particularly useful for use in an "application specific integrated circuit," (ASIC) chip design, where pre-designed "coreware" subsystems must be integrated in timely and cost effective design cycles. In such applications, design cycle times, technology, lack of readily available design tools (particularly for the newest available technologies), and expense prohibit exhaustive testing and redesign of complex designs.
The disclosed FIFO buffer and interface circuits allow the designer to concentrate on other more important issues of design. The disclosed FIFO system may simplify the base process of complex system design by allowing designers greater flexibility to partition designs into more manageable subsections.
The invention is disclosed in the context of a system having: (1) a first interface circuit that converts clocked binary signals from a first clock domain into asynchronous circuits in a "dual rail" signal format with NULL signals; (2) a series of asynchronous storage registers; and (3) a second interface circuit that converts signals from the dual rail format with NULL into clocked binary signals in a second clock domain. The asynchronous storage registers operate asynchronous from either clock domain.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described below in reference to the attached drawings in which:
FIG. 1a illustrates a central asynchronous logic FIFO buffer structure;
FIG. 1b illustrates an asynchronous logic register cell;
FIG. 2 illustrates a block diagram of an interface system transferring data from a first clock domain to a second clock domain.
FIG. 3a illustrates a circuit for converting from asynchronous, dual rail logic with NULL to clocked Boolean Logic;
FIG. 3b illustrates a circuit for converting from clocked Boolean logic to asynchronous, dual rail logic with NULL;
FIG. 4a illustrates the circuit of FIG. 3a modified with gated clock and synchronous reset sub-circuits;
FIG. 4b illustrates the circuit of FIG. 3b modified with gated clock and synchronous reset sub-circuits; and
FIG. 5 illustrates a block diagram of an interface using dual asynchronous FIFO buffers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Asynchronous circuits have been proposed that are intended to operate without a clock. One asynchronous logic paradigm is disclosed in U.S. Pat. No. 5,305,463 ("the '463 logic system") which is incorporated herein by reference in its entirety. Several data representations are discussed, but in one representation, a signal may assume a DATA value or a NULL value. A DATA value, for example might be a numeric value ZERO or ONE, or a logic value TRUE or FALSE, or another meaning not related to binary or Boolean logic representations.
In such a representation, a binary signal may take the form of two signal lines, with a first signal line designated to mean ZERO or FALSE, and the second signal line designated to mean ONE or TRUE. The pair of lines together represents a single binary variable (such as a single bit of binary data) and have four possible states: (1) DATA,DATA; (2) DATA,NULL; (3) NULL,DATA, (4) NULL,NULL. The first state (DATA/DATA) is not permitted. The second state (DATA,NULL) signifies that the variable has assumed the value ZERO (or FALSE). The third state (NULL, DATA) signifies that the variable has assumed the value ONE (or TRUE). The fourth state (NULL, NULL) lacks meaning, but can be thought of as indicating that the variable has not assumed a meaningful value.
In certain embodiments of the '463 logic system, signals cycle between NULL and DATA values at rates determined primarily by (1) the availability of complete data and (2) the switching speeds of the underlying physical devices. Periods of NULL separate periods of DATA, thus differentiating between different time values of the signals. Fixed-period clocks are not used to regulate the presentation of input signals to a circuit or to regulate the latching of output signals.
The preferred embodiments of the invention described herein represent certain binary variables as asynchronous, dual rail signals with periods of NULL separating periods of DATA. Such a representation will be referred to as "dual rail with NULL" or "DRN."
The '463 logic system may be implemented with threshold gate logic elements. U.S. Pat. Nos. 5,640,105 ("the '105 patent") and 5,656,948 ("the '948 patent") describe a number of implementations of threshold gates and are incorporated herein by reference in their entirety. Such gates can be characterized as having varying numbers of inputs and varying threshold values. Gates switched their outputs from NULL to DATA states when a threshold number of inputs are in the DATA state. Furthermore, such gates return their output to the NULL state only when all inputs return to NULL. Certain FIFO buffer structures disclosed herein may utilize elements of the '463 logic system and gates of the '105 and '948 patents.
System Overview
FIG. 2 illustrates inputs and outputs of a circuit for transferring data between two separate clocked domains.
The circuit 200 receives eight bits of binary digital data on signal lines 202 in Boolean binary format from an upstream CBL circuit 201. The upstream CBL circuit 201 provides a clock signal CLOCKIN1 on signal line 204 that is synchronous with the clock domain of the upstream CBL circuit 201. The circuit 200 also provides a protocol signal REQIN on signal line 208 and receives an acknowledge signal ACKIN on signal line 206. The circuit 200 requests data transfer using the REQIN signal on line 208, and the upstream CBL circuit 201 acknowledges the request using the ACKIN signal on line 206. Other interface handshaking protocols as are known in the prior art are possible. The circuit 200 also includes a RESET input on line 212. A CLOCKOUT1 output on line 210 can be used in an alternate data transfer protocol to the one using ACKIN and REQIN signal lines 206, 208 as discussed more fully below with reference to FIGS. 3b and 4b.
The circuit 200 provides data in Boolean binary format on signal lines 214 to a downstream CBL circuit 203. The downstream CBL circuit 203 provides a clock signal CLOCKIN2 on signal line 220 that is synchronous with the clock domain of the downstream CBL circuit 203. The circuit 200 also provides a protocol signal ACKOUT on signal lines 218 and receives a protocol signal REQOUT on signal line 216. The downstream CBL circuit 203 requests data transfer using the REQOUT signal on line 216, and the circuit 200 acknowledges the request using the ACKOUT signal on line 218. The circuit 200 also provides a CLOCKOUT2 output on line 222 that can be used as an alternate data transfer protocol to the one using REQOUT and ACKOUT signal lines 216, 218 as discussed more fully below with reference to FIGS. 3a and 4a.
Internally, the circuit 200 includes a CBL to DRN interface circuit 228, an asynchronous DRN FIFO 226, and a DRN to CBL interface circuit 228. The CBL to DRN interface circuit 228 converts Boolean binary format signals to dual rail with NULL format signals and transfers the data over data lines 230 to the DRN FIFO 226 under control of a single DACK/NACK signal on signal line 232. The DRN FIFO 226 provides first-in-first-out storage capacity, and transfers the data over signal lines 234 to DRN to CBL interface circuit 228 under control of a DACK/NACK signal on signal line 236.
Core DRN FIFO
FIG. 1a illustrates details of the DRN FIFO 226 of FIG. 2. It is a series of asynchronous registers 20, 22, 24, 26, 28. Asynchronous registers may be of a type described in U.S. Pat. No. 5,5652,902 ("the '902 patent"), which is incorporated here by reference in its entirety. FIG. 1a shows five asynchronous registers 20, 22, 24, 26, 28, however, different numbers and widths can be included to provide a desired capacity.
The first asynchronous register 20 receives on lines 21 data to be stored from CBL to DRN interface circuit 224 (FIG. 2). Data is expressed in dual rail with NULL format. Data propagates sequentially through each of the intermediate asynchronous registers 22, 24, 26, 26, to the last asynchronous register 28. The last asynchronous register 28 outputs data on lines 41 in dual rail with NULL format to a downstream interface circuit 228 (not shown).
Each asynchronous register 20, 22, 24,26, 28 locally propagates DATA and NULL wavefronts using DATA-acknowledge/NULL-acknowledge ("DACK/NACK") signals 30, 32, 34, 36, 38, 40, so that alternating wavefronts of NULL and DATA will cascade through the register stages. A DACK/NACK signal received at an asynchronous register from a downstream circuit (i.e., one that will receive the output from the asynchronous register) indicates whether the downstream circuit is ready to accept a DATA or NULL wavefront. For example, a DACK/NACK signal may assume a first value that indicates that the downstream circuit has received DATA and is ready to receive NULL, while a second state indicates that the downstream circuit has received NULL and is ready to receive DATA. Similarly, an asynchronous register generates a DACK/NACK signal to indicate its own state to an upstream circuit (i.e., one that will provide data).
For the purpose of illustration, the operation will be described with asynchronous registers 20, 22, 24, 26, 28 initially storing NULL. The downstream DRN to CBL interface circuit 228 (FIG. 2) will be assumed to be not ready to accept DATA, and will not communicate readiness to accept data on DACK/NACK signal line 40.
All asynchronous registers will initially signal to their immediately upstream asynchronous register (or in the case of the first asynchronous register 20, to the upstream interface circuit 224), that they are ready to receive DATA. The last asynchronous register 28 receives a DACK/NACK signal on signal line 40 that the downstream DRN to CBL circuit 228 (FIG. 2) is not ready to accept data.
When the upstream CBL to DRN circuit 224 (FIG. 2) presents DATA (and with the second asynchronous register 22 signaling readiness to receive DATA), the first asynchronous register stores the DATA, immediately presents it to the downstream asynchronous register 22, and signals on DACK/NACK signal line 30 that the first asynchronous register is ready to receive NULL. The second asynchronous register 22 similarly stores the DATA, immediately presents it to the third asynchronous register 24, and signals to the first asynchronous register 20 on DACK/NACK signal line 32 that the second asynchronous register 22 is ready to receive NULL. The DATA similarly cascades all the way to the last asynchronous register 28. The last asynchronous register 28 now stores DATA, and all upstream registers store DATA.
After the first asynchronous register 30 has stored DATA and signaled readiness to accept NULL, the upstream CBL to DRN interface circuit 224 (FIG. 2) presents NULL. With the second asynchronous register signaling readiness to accept NULL, the first asynchronous register 20 stores NULL, immediately presents it to the second asynchronous register 24, and switches its DACK/NACK signal line 30 to indicate readiness to receive more DATA. A wave of NULL cascades through the asynchronous registers in a complementary manner as discussed above for DATA, except that the NULL wave stops at the fourth asynchronous register 26 (because the downstream circuits are not ready to accept the next waves of NULL and DATA). The process repeats as long as the upstream CBL to DRN circuit 224 (FIG. 2) has DATA to deliver, and as long as the downstream DRN to CBL circuit 228 (FIG. 2) is not ready to receive DATA.
For the purpose of illustration, it will be assumed that the asynchronous registers fill up until the first, third, and last asynchronous registers 20, 24, 28 hold NULL, while the second and fourth asynchronous registers 22, 26 hold DATA. The first, third, and last asynchronous registers (which hold DATA) will continue to signal readiness to accept NULL, because their respective downstream circuits are not yet ready to receive DATA. Similarly, the second and fourth asynchronous registers 22, 26 (which hold NULL) will continue to signal readiness to accept DATA, because their respective downstream circuits are not yet ready to receive NULL. The circuit will not accept any more data.
When the downstream DRN to CBL circuit 228 (FIG. 2) signals on DACK/NACK signal line 40 its readiness to receive DATA, the last asynchronous register 28 will store DATA presented from the second-to-last asynchronous register 26, and switch its DACK/NACK signal line 38 to indicate that the last asynchronous register 28 is ready to receive NULL. The second-to-last asynchronous register will store NULL presented from the third asynchronous register 24 and switch its DACK/NACK signal line 36 to indicate that it is ready to receive DATA. The contents of each register 20, 22, 24, 26, 28 will shift down, while still maintaining NULL between DATA. The first asynchronous register 20 will then indicate readiness to accept DATA from the upstream CBL to DRN circuit 224 (FIG. 2).
FIG. 1b illustrates a cell of an asynchronous register. Signal lines D0 -- 0 -- In, D0 -- 1 -- In, D1 -- 0 -- In, D1 -- 1 -- In, . . . D7 -- 0 -- In, D7 -- 1 -- In carry signals from an upstream circuit (not shown). Signal lines D0 -- 0 -- Out, D0 -- 1 -- Out, D1 -- 0 -- Out, D0 -- 1 -- Out, . . . D7 -- 0 -- Out, D7 -- 1 -- 1 -- Out carry signals to a downstream circuit (not shown). The ACK -- IN 75 signal line carries a DACK/NACK signal from a downstream circuit (not shown). Signal line ACK -- OUT carries a DACK/NACK signal to an upstream circuit (not shown).
Gates 42, 44, 46, 48, . . . 70, 72 are threshold gates. The labels "22" inscribed in those threshold gate symbols signify that each gate has two inputs and a threshold of two (also known as a 2 of 2 threshold gate). That is, the output of a "22" gate will switch from NULL to DATA when two of the two inputs are DATA. Gates 23, 25, . . . 37 are also threshold gates. The labels "12" inscribed in those threshold gate symbols signify that each gate has two inputs and a threshold of one (also known as a 1 of 2 threshold gate). That is, the output of a "12" gate will switch from NULL to DATA when one of the two inputs are DATA. Both the "22" and "12" gates also exhibit hysteresis, so that the output will remain DATA until both inputs return to NULL.
FIG. 1b shows sixteen "22" gates 42, 44, 46, 48, . . . 70, 72 and eight "12" gates 23, 25, . . . 37 for illustration purposes. In this figure, two "22" gates are used to carry dual rail signals for each single bit of binary data in an eight-bit data word; hence the signal naming convention Dx -- 0 -- , Dx -- 1 -- , to denote the dual rail pairings in the figure. A single "12" gate 23, 25, . . . 37 is used for each dual rail "22" gate pair to provide data acknowledge detection for the dual rail signal. Additional gates can be added to provide more width to the register. Examples of transistor diagrams for threshold gates can be found in the '948 patent.
The hysteresis characteristic of threshold gates 42, 44, 46, 48, . . . 70, 72 provides a memory capability. As long as a downstream circuit holds a DATA level signal on ACK -- IN line 75, the gates 42, 44, 46, 48, . . . 70, 72 will hold a previously-set DATA state, even if the inputs D0 -- 0 -- In, D0 -- 1 In, D1 -- 0 -- In, D1 -- 1 -- In, . . . D7 -- 0 -- In, D7 -- 1 -- In return to NULL.
Gate 76 is a threshold gate. The label "88" signifies that it has eight inputs and a threshold of eight. It collects the individual bit acknowledge signals of the data acknowledge detection gates 23, 25, . . . 37 and provides a single acknowledge signal when all are DATA to the upstream DRN circuit. The combination of "88" gate 76 and "12" gates 22, 24, . . . 36 serves as a "watcher" circuit. It senses the states of all output signal lines D0 -- 0 -- Out, D0 -- 1 -- Out, D1 -- 0 -- Out, D1 -- 1 -- Out, . . . D7 -- 0 -- Out, D7 -- 1 -- Out and indicates that one of each of the eight pairs of threshold gates 42, 44, 46, 48 . . . 70, 72 have achieved a DATA state, or that all sixteen of gates 42, 44, 46, 48, . . . 70, 72 have achieved a NULL state. (Depending on the cell width, the number of "12" gates and the inputs and the threshold of Gate 76 can be changed.)
Gate 78 is an inverting gate that outputs a NULL level when its input is DATA and vice versa. It inverts the output of gate 76 so that next DATA or NULL wave is properly requested from the upstream circuitry (a NULL output is a request for NULL from the upstream circuitry, a DATA level output is a request for DATA).
DRN to CBL Interface
The DRN logic signals described above propagate alternating waves of NULL and DATA through their circuitry. Clocked Boolean Logic does not have this same characteristic. When using a DRN FIFO buffer of the type disclosed above, the CBL to DRN interface circuit 224 (FIG. 2) must insert the NULL wave, and the DRN to CBL circuit 228 (FIG. 2) must remove the NULL wave. Alternatively, the NULL wave could be present in the data stream already. However, such a solution adds either software or hardware overhead elsewhere in the non-DRN system.
To facilitate interfacing a clocked Boolean circuit must be able to request data from a NULL wave system and then wait for it. Similarly, a clocked Boolean circuit must wait for a DATA-Acknowledge/Null-Acknowledge before transferring DATA to it.
FIG. 3a illustrates details of a first DRN to CBL interface 717 which can be used as the DRN to CBL interface circuit 228 of FIG. 2. FIG. 3a uses a number of well-known graphic symbols for Boolean logic elements, such as AND gates 763, 761, OR gates, 762, 764, latches 751, 752, 753, 754, multiplexers 769, 770, and inverters 765, 766. FIG. 3a also includes a number of threshold gates 767, 768.
The interface 717 illustrated details of circuits for transferring a single, binary-value signal, such as a binary bit (ZERO or ONE ) or a binary logic signal (TRUE or FALSE). The Data signal on line 701 is a single signal line carrying a Boolean binary format representation of a single binary bit. The ground voltage state represents binary ZERO, and a supply voltage state represents binary ONE. The ˜Data signal line 702 is an inverted form of the Data signal line 701.
The circuit 717 receives a single besentation of a single binary bit on two signal lines 716,715, each having two voltage states. The first line 716 is assigned a meaning of "ONE," and the second line 715 is assigned a meaning of "ZERO." On the first line 716, a supply voltage expresses the meaning of the line, while the ground voltage does not express the meaning of the line, which is the state called NULL. The two lines together carry a single binary bit of information. When the Data -- 0 line 716 is at the supply voltage and the Data -- 1 line 715 is at the ground voltage, the two lines together signify a binary ZERO. When the Data -- 1 715 is at the supply level and the Data -- 0 line 716 is at the ground level, the two lines together signify a binary ONE. When both lines 715, 716 are at the ground level, the signal has no meaning and are in the NULL state. It is not permitted for both lines to be at supply level at the same time.
The interface circuit 717 connects to an upstream DRN circuit, such as the DRN FIFO 226 of FIG. 2, and to a downstream Boolean circuit, such as the CBL circuit 203 (FIG. 2). The DACK/NACK signal line 710 signifies to an upstream asynchronous circuit that the interface circuit 717 is ready to receive the next DATA or NULL wavefront.
The Clock -- 2 signal line 712 is a system clock from a downstream Boolean circuit (not shown). The Request signal line 703 and the Acknowledge signal line 704 are used in a protocol to transfer data to a downstream Boolean circuit. The Request signal line 703, when high, indicates that the downstream Boolean circuit is ready to receive new data. The Acknowledge signal line 704, when high, indicates that the interface circuit has data ready to be transferred.
The interface circuit 717 shown in FIG. 3a illustrates details of circuitry for converting a single bit of binary information from DRN to CBL format. Input signal lines 715, 716 carry the information as alternating wavefronts of NULL and DATA. The binary output signal Data on signal line 701 is derived from the DATA -- 1 input on signal line 716. Subject to timing considerations of passing data through latches 751, 752 as discussed below, when DATA -- 1 becomes meaningful (supply voltage level), the DATA output line 701 will assume the supply voltage level, signifying binary numeral ONE. When DATA -- 0 becomes meaningful (supply voltage level) and DATA -- 1 is NULL (ground voltage level), the DATA output line 701 will assume the ground voltage, signifying binary numeral ZERO. The ˜DATA line 702 operates in an identical manner, but is based on the DATA -- 0 input line 715, and produces a result that is inverted relative to the DATA line 701.
The interface circuit 717 stores the data received on signal lines 715, 716, in latches 751 and 753 on the next negative-going transition of the Clock -- 2 signal line 712. These latches 715, 716 prevent metastability under certain circumstances and may be omitted without destroying the utility of the circuit. The following positive-going transition of Clock -- 2 clocks the data into latches 752 and 754.
The interface circuit 717 accepts requests for data from a downstream CBL circuit (not shown) on request signal line 703, and issues an acknowledge signal on acknowledge signal line 704 when data is ready. Data is sent out to the clocked Boolean circuit on the DATA line 701 at the same time as the Acknowledge signal, both of which transition in synchrony with the local clock signal, Clock -- 2 on line 712. Signal line 702 is the inverted, negative-logic version of line 701 and may be used instead of signals on line 701 by the downstream circuitry if negative logic is desired.
The interface circuit 717 requests data from the upstream DRN circuit (not shown) on DACK/NACK signal line 710 after transferring and emptying information from latch 752 (and/or latch 754). The interface circuit 717 accepts the next data wavefront on signal lines 716 and 715 (Data -- 0 and Data -- 1). The data will be stored and made ready for transfer to the downstream CBL logic circuit upon request.
When a data request signal from the downstream CBL circuit arrives on signal line 703, it causes AND gate 761 to generate an acknowledge signal on signal line 704 if data is ready for transfer from latches 752 and 754. If no data is ready in latches 752 and 754, a low signal from threshold gate 767 blocks the request until data is ready. After AND gate 761 generates an (active high) acknowledge signal, a latch 755 in hold circuit 719 turns off the acknowledge signal (returns it to a low level) on the next cycle of Clock -- 2 by sending a low signal on line 707 to AND gate 761.
The hold circuit 719 also includes OR gate 762 and AND gate 763. The output of OR gate 762 also passes through OR gate 764 to the control inputs of multiplexers 769, 770. Multiplexers 769, 770 selectively connect the inputs of latches 752, 754 either to their own respective outputs or to incoming data received through latches 753, 751. Thus, when the Acknowledge signal on line 704 is high or hold circuit 719 is active, and multiplexers 769, 770 are enabled to pass data wavefronts from latches 751, 752 into latches 752, 754.
When latches 752, 754 hold meaningful data from the upstream DRN circuitry, one will hold a DATA value, and the other will hold a NULL value. The output of threshold gate 768 will be asserted (i.e., not NULL). In contrast, when latches 752, 754 both hold NULL values, the output of threshold gate 768 will be NULL. When the interface circuit has been expanded to contain multiple replicas of the data-handling circuits 717, the outputs from corresponding threshold gates 768 from all replicas are collected as inputs to threshold gate 767.
Threshold gate 767 will generate an output on line 708 that performs several functions. First, it forms the basis for a DACK/NACK signal on line 710 (after being inverted by inverter 766). The DACK/NACK signal indicates to upstream circuitry whether the latches 752, 754 hold NULL or meaningful data, which signals that the upstream circuit can now send a complementary waveform (DATA if the latches hold NULL, or NULL if the latches hold DATA). A transition to high on signal line 708 switches the output of inverter 766 from high to low, which in turn converts the DACK/NACK signal from a "request for data" into a "request for NULL."
Second, threshold gate 767 provides a control signal for multiplexers 769, 770. A low signal from inverter 766 (passing through OR gate 764) sets multiplexers 769 and 770 to re-circulate data from the outputs of latches 752 and 754 to their respective inputs. Thus holding the data over multiple clock cycles until needed by the downstream CBL circuitry.
Third, threshold gate 767 provides an input to hold circuit 719. When NULL, the output of threshold gate 767 resets the hold circuit 719 by clocking a low level into latch 795. When NULL, it also switches multiplexers 770 and 769 to pass new data from latches 751, 753 to latches 752, 754.
The Reset signal line 711 resets all flip flops 751, 752, 753, 754, 755 of the interface. Upon power up or reset, the interface circuit 717 of FIG. 3a does not service requests for data from a downstream CBL circuit until data flows through from the upstream DRN circuit. Similarly, after servicing a first request for data, the interface circuit 717 will not service a second data request from a downstream CBL circuit until it receives new data. This characteristic prevents data overflow and underflow.
More specifically, an active (high) signal on the Reset line 711 resets all latches 751, 752, 753, 754 placing a logic low on all their "Q" outputs. Signal lines 701 and 702 assume low or ZERO levels. Threshold gate 768 changes its output to NULL, which forces the output of AND gate 761 low and prevents it from providing an affirmative acknowledge signal 704 to the downstream clocked Boolean circuit. Inverter 766 inverts the NULL level on signal line 708 to provide the "request for data" signal to the upstream circuit on signal line 710, and (through OR gate 764) switches the multiplexers 770, 769 to pass data from the upstream circuit. The interface circuit 717 then waits for more data from the upstream circuit and does not respond to data requests from the downstream circuit until threshold gate 768 senses the arrival of data in latch 752, 754.
The circuit of FIG. 3a illustrates a transfer of a single bit of data. It can be expanded in width to transfer multiple bits simultaneously, such as for 8-bit, 16-bit, 32-bit or larger data words, by replicating the data-carrying circuitry 717. In addition, all outputs of replicas of threshold gate 768 should be made inputs to the single threshold gate 767, and the threshold of the gate 767 should be increased according to the number of inputs.
FIG. 4a illustrates the circuit of FIG. 3a but modified with two additional features: 1) a synchronous reset capability, and 2) a gated clock for use as an alternative protocol for transferring clocked data to a clocked Boolean circuit. Circuit elements that are the same in FIGS. 3a and 4a have the same reference numerals.
With regard to the synchronous reset feature, the external Reset signal from line 711 passes through the data inputs of two series connected latches 757, 758 that are clocked by the Clock -- 2 signal from line 712. The external Reset line 711 also connects to the SET inputs of latches 757, 758. When the external Reset line 711 is active (high), it immediately sets both latches 758, 757, which in turn drives internal reset line 773 to clear latches 751, 752, 753, 754, 755, 765. When the external Reset line is no longer active, the previously-set latches 757, 758 maintain the internal reset line active for at least one clock cycle of the Clock -- 2 signal on line 712, which isolates any potential metastability problems associated with the asynchronous external reset. This local reset may also be passed on and used to reset other circuitry.
With regard to the gated clock feature, the Clock -- 2 signal from signal line 712 via inverter 773 clocks the Acknowledge signal from AND gate 761 into latch 756 on the falling clock edge to help avoid race conditions with subsequent AND gate 771. The output of latch 756 in turn connects to an input of AND gate 771, which also receives Clock -- 2 as an input. The output of latch 756 thus gates the Clock -- 2 signal so that transitions of the Clock -- 2 signal only appear on Clock -- 2 -- Gated line 772 when the acknowledge signal indicates the readiness of data for transfer from latches 752, 754.
The gated clock signal on line 772 can serve as an alternative handshaking protocol to the above-described request/acknowledge handshaking. The circuit provides a clock (Clock -- 2 -- Gated) to a downstream clocked Boolean circuit only when actively transferring data. The downstream circuit may stop the clock after receiving the data by dropping the Request signal line 703 LOW.
CBL to DRN Interface
FIG. 3b illustrates a circuit 818 that may be used as the CBL to DRN interface circuit 224 (FIG. 2). A CBL circuit provides a Data signal in binary format on line 801, and also provides a Clock -- 1 signal on line 813. Reset line 811 is an input for resetting the circuit. The interface circuit 818 provides DATA and NULL signals in DRN format to a downstream asynchronous circuit on Data -- 0 and Data -- 1 signal lines 804, 805. Acknowledge and Request lines 803, 802 coordinate data flow between the interface circuit and the upstream CBL circuit. A DACK/NACK signal on signal line 806 coordinates data flow to the downstream DRN circuit.
Data format conversion from Boolean binary format to a DRN format involves latches 853, 854, 855. The interface circuit 818 stores binary data received on line 801 in latch 853, where a ground level voltage signifies a binary ZERO, and a supply level voltage signifies a binary ONE. The data output of latch 853 passes through one input of multiplexer 870 and then splits along two paths. One path passes through inverter 871, multiplexer 873 and AND gate 874 to the data input of latch 854. The second path passes through multiplexer 872 and AND gate 875 to the data input of latch 855. At latches 854, 855, ground voltage levels signify NULL, and supply voltage levels signify DATA. More specifically, a DATA level at latch 854 signifies a numeric value ZERO (or logic value FALSE), and a DATA level at latch 855 signifies a numeric value ONE (or a logic value TRUE).
The interface circuit 818 requests data from an upstream CBL circuit by setting Request line 802 to HIGH. The HIGH Request level on line 802 also prepares the interface circuit 818 to receive data by switching multiplexer 868 to connect data line 801 to the data input of latch 853. The Request signal on line 802 also passes through inverter 869 to switch multiplexer 870 to connect the output of latch 853 to the split data paths of line 812. (One path leads through inverter 871 to multiplexer 873, the other path leads directly to multiplexer 872.)
The upstream circuit responds to a HIGH level on Request line 802 by setting Acknowledge line 803 to HIGH and placing new data on signal line 801. Latch 853 stores the data from the CBL circuit on the next positive-going transition of the Clock -- 1 transfer clock on line 813.
The HIGH Acknowledge level on line 803 passes immediately through OR gate 864 and signal line 809 to multiplexers 873, 872, causing each to connect one of the two split data paths to one of two AND gates 874, 875. (This prepares the interface circuit 818 to deliver data to the downstream circuit as discussed more fully below).
The High Acknowledge level on line 803 also passes through OR gate 864 and is stored in latch 852 on the same clock transition that data is stored into latch 853. The HIGH level then appears on the output of latch 852 and passes through signal net 810. Inverter 866 receives the HIGH signal from net 810, inverts it, and disables AND gate 867, thereby resetting the Request line 802 to a LOW level and canceling the previous request for data. The resetting of the Request line 802 triggers a reconfiguration of the interface circuit 818 to deliver data to a downstream circuit. The LOW level on line 802 also switches multiplexer 868 to re-circulate previously-stored data back into latch 853 on subsequent cycles of the clock on line 813, thus blocking receipt of additional data until after transmitting previously-received data. The signal path that passes from the output of the latch 852 back to its own input (via AND gate 865 and OR gate 464) returns the HIGH level, thus maintaining the stored HIGH level during subsequent cycles of the clock on line 813. As mentioned above, with the new data having been latched in from the upstream CBL circuit, multiplexers 873 and 872 are set to stop re-circulating current data, and to pass new data forward from signal line 812.
A DRN circuit (such as the DRN FIFO of FIG. 2) requests DATA by setting DACK/NACK line 806 to DATA. If the data fans out to multiple downstream DRN circuits, threshold gate 861 collects DACK/NACK signals from all of them, and delivers a single request to the input of latch 851 when all downstream circuits have signaled for the data. (Gate 861 is shown with four inputs and a threshold of four, which assumes four downstream circuits in this example.) Latch 851 stores this signal on the next negative-going transition on clock line 813, which isolates metastability from the latches 854, 855.
A HIGH (or DATA) level output from latch 851 on signal line 808 enables AND gates 874, 875 to pass DATA to latches 854, 855, which store DATA on the next rising transition of the clock on signal line 813. One of the two latches 854, 855 stores a ground voltage level, which corresponds to a NULL signal for the downstream circuit, while the other stores a supply voltage level, which corresponds to a DATA signal.
The latches 854, 855 place their stored levels on their respective output lines 804, 805. Threshold gate 876 detects the presence of DATA on output lines 804, 805 and generates a supply level (DATA) signal that propagates through threshold gate 878 and inverter 877 to become a low level on line 807. The low value appears at the input to AND gate 867 and cancels the previous data request on line 802. The low level also appears at the input to AND gate 865 and clears (stores a low level in) latch 852. The clearing of latch 852 in turn sets multiplexers 872 and 873 to re-circulate data into the latches 854, 855, thus holding the DATA. The clearing of latch 852 also sets multiplexers 868, 870 to pass new data from the upstream circuit to latch 853. Thus, when the interface presents data to the downstream circuit on lines 804, 805, it immediately enables itself to request and receive new data from the upstream circuit.
The downstream DRN circuit(s) will store the DATA upon receiving it from lines 804, 805. After storing DATA, the downstream DRN circuit(s) will request a wavefront of NULL by setting DACK/NACK signal line 806 to NULL. When all downstream circuits request NULL, threshold gate 861 outputs a LOW signal. Latch 851 loads the LOW signal on the next negative-going transition on clock line 813, which isolates metastability problems from the latches 854, 855. The LOW output from latch 851 in turn reaches AND gates 875, 875 and forces their outputs to LOW. Latches 854, 855 store these LOW level signals on the next rising transition on clock line 813, and thus present LOW on both output lines 804, 805, which corresponds to generating a NULL wavefront. Threshold gate 876 senses the NULL wavefront on signal lines 804 and 805 and generates a NULL (low) output. Threshold gate 878 in turn generates a low output, which inverter 877 converts to high on line 807. The high level of line 807 enables AND gate 867 to request new data from the upstream circuit. One data transfer is thus complete.
A high signal on Reset line 811 can be used to reset latches 851, 852, 853, 854, and 855 into a known states (storing low levels) that correspond to holding no data. Threshold gate 867 senses the presence of NULL on output signal lines 804, 805 and generates NULL. Gate 878 in turn collects the separate gate 867 signals and generates NULL, and inverter 877 drives signal line 807 high, which enables a data request on line 802, and which further configures the circuit to receive DATA as discussed above. A high signal on line 802 passes through inverter 869 to control multiplexer 870 to connect Data line 801 directly to signal line 812. This direct connection provides a "pre-charge" to the latches 854, 855, which avoids a one clock long "dead spot" that otherwise would exist when receiving the first new data. Thus, the data is presented to the Asynchronous logic conversion stages of the interface as soon as it and the corresponding acknowledge signal arrive so they can be immediately utilized, if the following conversion stages are ready.
FIG. 4b illustrates the circuit of FIG. 3b but modified with: 1) a synchronous reset capability, and 2) a gated clock for use as an alternative protocol for transferring clocked data to a clocked Boolean circuit. Circuit elements that are the same in FIGS. 3b and 4b have the same reference numerals.
With regard to the synchronous reset feature, the external reset signal from line 811 passes through the data inputs of two series latches 856, 857 that are clocked by the Clock -- 1 signal from line 813. The external Reset line 811 also connects to the SET inputs of latches 856, 857. When the external Reset line 811 is active (high), it immediately sets both latches 856, 857, which in turn drives internal reset line 815 to clear latches 851, 852, 853, 854, and 855. When the external Reset line is low (no longer active), the previously-set latches 856, 857 maintain the internal reset line active for at least one cycle of the Clock -- 1 signal on line 712, which isolates any potential metastability problems associated with the asynchronous external reset. This local reset may also be used to reset the attached external circuitry.
With regard to the gated clock feature, the Clock -- 1 signal from signal line 813 via inverter 880 clocks the Request signal from AND gate 867 into latch 858 on the falling clock edge to avoid race conditions with the subsequent AND gate 879. The output of latch 858 in turn connects to an input of AND gate 879 which also receives Clock -- 1 as an input. The output of latch 858 thus gates the Clock -- 1 signal so that transitions of the Clock -- 1 signal only appear on line 817 when the request signal indicates the readiness for data transfer to latch 853.
The gated clock signal on line 817 can serve as an alternative handshaking protocol if the downstream circuitry cannot utilize the above -- described request/acknowledge handshaking. The circuit provides a clock (Clock -- 1 -- Gated) to an upstream CBL circuit only when actively transferring data. The interface circuit may stop the clock after receiving the data by dropping the Request signal line 802 LOW.
NULL Wave Induced Latency
When converting from a CBL data representation to a DRN representation, NULL waves must be inserted between DATA waves. In the FIFO architecture of FIG. 1a, separate registers hold the NULL and DATA waves, therefore, a DRN FIFO must complete two transfer cycles (one NULL and one DATA) for each transfer of data from a CBL circuit. However, the actual throughput rate of a DRN FIFO buffer will be better than half that of a clocked FIFO buffer, because the DRN FIFO completes a cycle as fast as the physical devices will permit, while a clocked FIFO will be limited to the actual clock rate. Even in systems where the data rate approaches the physical switching rate of the underlying circuitry, the asynchronous FIFO buffer of FIG. 1a will be better than one -- half as fast as a clocked FIFO, because the clocked FIFO will have some inherent margin between the clock rate and the physical device switching rate. In situations where absolute speed in important, asynchronous FIFO buffers can be designed to increase throughput.
FIG. 5 illustrates a buffer architecture that increases throughput relative to the architecture of FIG. 2. The architecture of FIG. 5 receives a clocked data stream on signal lines 101 using a protocol controlled by acknowledge and request signals on lines 103, 105. A clocked demultiplexer 107 splits the data stream in two and directs alternate data words down each of two paths to one of two CBL to DRN interfaces 109, 111. In the example shown, each interface converts eight binary data lines into sixteen dual rail signal lines. Each of two DRN FIFO buffers 113, 115 transfers one of the split data streams to one of two DRN to BCL interfaces 117, 119. The DRN to CBL interfaces remove the NULL waves and convert the sixteen dual rail signal lines to eight binary signal lines. A multiplexer 121 reassembles the two data streams back into a single data stream on lines 123 and transfers the data to a receiving circuit using acknowledge and request signals on signal lines 125, 127.
Each DRN FIFO buffer 113, 115 can be half as deep as a single FIFO buffer while still holding the same absolute amount of information because of the increased effective width. Furthermore, the reduced depth also reduces the latency of the dual-FIFO architecture to half that of a single FIFO architecture.
The CBL to DRN interface circuits 109, 111 may be the same as those illustrated in FIGS. 3b and 4b. The DRN to CBL interface circuits 117, 119 may be the same as those illustrated in FIGS. 3a and 4a. The FIFO buffers may be the same as the one illustrated in FIGS. 1a and 1b.
From the above exemplary embodiments and detailed descriptions it will be appreciated that effective developments are represented in the fields of electronics an computers. These concepts, techniques, and systems have widespread application and to those skilled in the art, numerous modifications and alternative systems will be suggested. | An asynchronous FIFO using Asynchronous NULL Convention LOGIC (NCL) to facilitate interfacing between multiple non-synchronous systems with a minimum of design and verification. Multiple interfaces, configurations, means for minimizing latency, and capabilities for datastream processing are also incorporated. | 6 |
CROSS RELATED APPLICATION
This applications claims priority to U.S. Provisional Patent Application Ser. No. 61/598,112 filed Feb. 13, 2012.
BACKGROUND OF THE INVENTION
The present invention relates to flashing fluids extracted from pressurized reactor vessels and particularly to flash tanks for flashing black liquor from a pressurized reactor vessel in a pulping or biomass treatment system.
Flash tanks are generally used to flash a high pressure fluid liquor stream including steam and condensate. A flash tank typically has a high pressure inlet port, an interior chamber, an upper steam or gas discharge port and a lower condensate or liquid discharge port. Flash tanks safely and efficiently reduce pressure in a pressurized fluid stream, allow recovery of heat energy from the stream, and collect chemicals from the stream in condensate.
Flash tanks may be used to recover chemicals from chemical pulping systems, such as Kraft cooking systems. Flash tanks are also used in other types of cooking systems for chemical and mechanical-chemical pulping systems. To pulp wood chips or other comminuted cellulosic fibrous organic material (collectively referred to herein as “cellulosic material”), the cellulosic material is mixed with liquors, e.g., water and cooking chemicals, and pumped in a pressurized treatment vessel. Sodium hydroxide, sodium sulfite and other alkali chemicals are used to “cook” the cellulosic material such as in a Kraft cooking process. These chemicals degrade lignins and other hemicellulose compounds in the cellulosic material. The Kraft cooking process is typically performed at temperatures in a range of 100 degrees Celsius (100° C.) to 170° C. and at pressures at or substantially greater than atmospheric.
The cooking (reactor) vessels may be batch or continuous flow vessels. The cooking vessels are generally vertically oriented and may be sufficiently large to process 1,000 tons or more of cellulosic material per day. The material continuously enters and leaves the vessel, and remains in the vessel for several hours. In addition to the cooking vessel, a conventional pulping system may include other reactor vessels (such as vessels operating at or near atmospheric pressure or pressurized above atmospheric pressure) such as for impregnating the cellulosic material with liquors prior to the cooking vessel. In view of the large amount cellulosic material in the impregnation and cooking vessels, a large volume of black liquor is typically extracted from these vessels.
The black liquor includes the cooking chemicals and organic chemicals or compounds, e.g., hydrolysate, residual alkali, lignin, hemicellulose and other dissolved organic substances, dissolved from the cellulosic materials. The black liquor is flashed in a flash tank to generate steam and condensate. The cooking chemicals and organic compounds are included with the liquid condensate formed when the liquor is flashed. The steam formed from flashing is generally free of the chemicals and organic compounds. The condensate is processed to, for example, recover and recausticize the cooking chemical. The steam may be used as heat energy in the pulping system.
In conventional flash tanks, the black liquor enters flash tanks through an inlet pipe having a fixed inlet diameter. The inlet is not variable or otherwise controllable to adjust the size of the black liquor flow passage. Changes to the flow passage at the inlet to a conventional flash tank for black liquor have been made by changing the inlet piping to the flash tank. Conventional flash tanks do not have a means for adjusting the flow passage; controlling of the volume or the velocity of the black liquor flow into the flash tank, pressure drop in the flash tank, or regulating the pressure in the conduits containing black liquor connected to the inlets to the flash tanks.
BRIEF DESCRIPTION OF THE INVENTION
An inlet for a flash tank has been conceived where the flow passage area of the inlet to the flash tank is varied to allow for control of the flow passage area of the inlet to the flash tank without changing of physical or mechanical components of the inlet or flash tank. The flow passage area is adjusted by a pivoting hinged plate in the inlet to the flash tank. This movable, hinged plate may be located at, near or after the junction between piping and the inlet to the flash tank. At this junction, the piping typically transitions from piping having a rectangular cross-section to piping circular in cross-section.
The movable, hinged plate changes of the cross-sectional area of the inlet to adjust the flow passage area through which hot black liquor flows from fully open to smaller area or from a smaller area to a larger area. This adjustment of the inlet opening size provides a means to control the velocity of the fluid into the tank.
The movable, hinged plate may be operated by a pneumatic or electro-mechanical actuator. A formable seal may be provided on either the movable hinged plate or the interior of the pipe to prevent leaking of hot black liquor out of the pipe or past the side edges of the plate.
A flash tank has been conceived including: a closed interior chamber; a gas exhaust port coupled to an upper portion of the chamber; a liquid discharge port coupled to a lower portion of the chamber; an inlet nozzle attached to an inlet port of the chamber, wherein the inlet nozzle includes a flow passage having a throat, and a movable valve plate in the flow passage, wherein the valve plate has a first position which defines a first throat area in the flow passage and a second position which defines a second throat area having a smaller cross-sectional area than the first throat area.
The valve plate may be a rectangular plate having planar surfaces bounded by edges and the flow passage may have a rectangular cross-section. The rectangular plate may be attached to a hinge attached to a sidewall of the flow passage. The hinge may be attached to an upstream end of the valve plate and creates a pivoting axis for the valve plate.
The valve plate may have an actuator connected to the valve plate, wherein the actuator moves the valve plate between the first and second positions.
The valve plate may be moved by an actuator having an extendible shaft connected to the valve plate, wherein the actuator moves the valve plate between the first and second positions.
A method has been conceived to flash a pressurized liquor comprising: feeding a pressurized liquor to an inlet nozzle of a flash tank; flashing the pressurized liquor as the liquor flows from the inlet nozzle into an interior chamber of the flash tank; exhausting a gas exhaust formed by the flashing through an upper portion of the chamber; discharging a liquid formed by the flashing from a lower portion of the chamber, and adjusting a cross-sectional area of a flow passage in the inlet nozzle by moving a valve plate in the flow passage.
The step of feeding may include a first feeding step in which the pressurized liquor flows through the flow passage while the valve plate is at a first position which defines a first throat area in the flow passage and a second feeding step in which the pressurized liquor flows through the flow passage while the valve plate is in a second position which defines a second throat area having a smaller cross-sectional area than the first throat area. Additional valve plate positions may also exist where the valve plate in multiple positions along the flow passage define multiple throats having smaller cross-sectional areas than the first throat area.
The method may include adjusting the cross-sectional area of the flow passage in the inlet nozzle allows for control of the volume of flow of black liquor entering the flash tank. Adjusting of the cross-sectional area of the flow passage inlet nozzle may also allow for control of the flow velocity of the black liquor entering the flash tank. Additionally, adjusting the cross-sectional area of the flow passage in the inlet nozzle allows for a degree of control over the pressure drop in the flash tank. Adjusting the cross-sectional area of the flow passage in the inlet nozzle may also ensure sufficient pressure in the conduits upstream of the inlet nozzle to the flash tank.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a conventional flash tank receiving black liquor extracted from a pressurized reactor vessel.
FIG. 2 is cross-sectional view of the flash tank taken along a horizontal line, wherein the inlet nozzle is attached to the tank along a tangent to tank.
FIG. 3 shows a perspective and partially cut-away view of the inlet nozzle to illustrate the valve plate and the connection of the nozzle to the sidewall of the flash tank.
FIG. 4 is a cross-sectional schematic view of the inlet nozzle taken along a vertical plane to illustrate the valve plate.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic diagram of a pulping system including a flash tank 10 coupled to a vessel 12 , e.g., an impregnation vessel or a cooking vessel. A slurry of cellulosic material 14 and liquor flow to an upper inlet 15 of the vessel 12 . White liquor 16 may be added to the vessel 12 such as through center inlet pipes 18 . Screen assemblies 20 at various elevations in the vessel 12 extract black liquor from the cellulosic material moving down through the vessel 12 . The material is discharged as pulp 22 from the bottom 24 of the vessel.
The black liquor extracted from the vessel 12 may flow to the flash tank 10 through conduits 26 fluidly coupling the screen assemblies 20 to a respective flash tank 10 . The number of flash tanks 10 and whether one flash tank 10 receives black liquor from multiple screen assemblies 20 are design choices. The number, size and arrangement of flash tanks 10 may also depend on the design choice of whether to have heat exchange equipment in the conduits 26 leading to the flash tanks 10 .
Black liquor flashes in the flash tank 10 to form steam 28 and condensate 30 . The steam 28 flows out upper outlets 17 of the flash tanks 10 . The condensate 30 flows as a liquid from bottom discharges 19 of the flash tanks 10 .
FIG. 2 is a cross-sectional view of the flash tank 10 , wherein the cross-section is along a horizontal plane bisecting the inlet piping system to the flash tank 10 . The conduits 26 transporting the black liquor to be flashed may be cylindrical pipes. The inlet nozzle 34 to the flash tank 10 may be rectangular in cross-section. An end outlet 32 of the conduits 26 connects to the inlet nozzle 34 attached to the flash tank 10 . The inlet nozzle 34 may be tangential to a cylindrical portion 38 of the flash tank 10 .
The flash tank 10 need not be cylindrical and the inlet nozzle 34 need not be tangential to the flash tank 10 . The flash tank 10 may have planar sections in its sidewall. Other suitable configurations of the inlet nozzle 34 may be oriented vertically and attached to the top of the flash tank 10 or to the side of the flash tank 10 without being tangential to the sidewall of the flash tank 10 .
The flow passage 40 through inlet nozzle 34 may be rectangular, e.g., square, in cross-section. The rectangular cross section allows a valve plate 42 in the flow passage 40 to move, e.g., pivot, within the flow passage 40 . The valve plate 42 regulates the velocity of the flow stream of black liquor to the flash tank 10 .
A transition section 44 at the upstream end of the inlet nozzle 34 may convert a round inlet to a rectangular cross section of the remainder of the flow passage 40 through the inlet nozzle 34 . The inlet of the transition section 44 connects to the end of the conduit 26 . The outlet of the transition section 44 connects to the inlet nozzle 34 . The transition section 44 may include a flange coupling 31 to attach to an end outlet 32 of the conduit 26 .
FIG. 3 illustrates an exemplary valve plate 42 in the inlet nozzle 34 . The inlet nozzle 34 extends tangentially to the cylindrical portion 38 of the flash tank 10 . The valve plate 42 may be attached to a hinge 46 fixed to a sidewall 48 of the flow passage 40 through the inlet nozzle 34 . An upstream end 50 end of the valve plate 42 is fixed to the hinge 46 and may be adjacent the sidewall 48 .
Pressurized black liquor flows through the flow passage 40 and, specifically, between the valve plate 42 and an opposite sidewall 52 of the inlet nozzle 34 . The valve plate 42 may extend downstream such that the downstream edge 54 of the valve plate 42 is proximate to an opening 56 in the side of the cylindrical portion 38 of the flash tank 10 .
The valve plate 42 pivots, see arrow 58 , about the vertical axis of the hinge 46 . The range of angles through which the valve plate 42 pivots is a design parameter to be selected during the design of the inlet nozzle 34 . The range of angles may swing the valve plate 42 from being adjacent to the sidewall 48 (a zero angle position) to a maximum angle position where the downstream edge 54 abuts the end of the opposite sidewall 52 .
The downstream edge 54 of the valve plate 42 will form an edge of the throat area (T in FIGS. 2 and 4 ) of the flow passage 40 . The throat area T is the narrowest cross-sectional area of the flow passage 40 . The throat area T is directly related to the capacity, quantity of black liquor the flow passage 40 is capable of passing to the flash tank 10 . The throat area T of the flow passage 40 is widest and has a maximum capacity when the angle of the valve plate 42 is zero and the valve plate 42 is adjacent the sidewall 48 . The throat area T of the flow passage 40 is narrowest and has a minimum capacity, which may be a zero flow rate, when the valve plate 42 is at a maximum angle the downstream edge 54 nearest the opposite sidewall 52 of the flash tank 10 .
The downstream edge 54 of the valve plate 42 may have a replaceable or hardened strip 60 , e.g., soft metal such as copper or a plastic material capable of withstanding the abrasive conditions such as those from the black liquor, which may be available to act as a seal between the downstream edge 54 of the valve plate 42 and the opposite sidewall 52 or interior wall of the flash tank 10 . A similar strip 60 may be along the upper and lower side edges of the valve plate 42 .
FIG. 4 is a cross-sectional schematic diagram of the inlet nozzle 34 taken along a vertical plane and showing a side of the flash tank 10 . FIG. 4 shows a view looking directly into the inlet nozzle 34 in a downstream direction of the flow passage 40 . The rectangular cross-sectional shape of the flow passage 40 is evident as is the oval or circular shape of the opening 56 to the flash tank 10 . The valve plate 42 is shown extending partially across the flow passage 40 and forming a rectangular throat area (T). The valve plate also extends across and blocks a portion of the opening 56 to the flash tank 10 .
The area of the flow passage 40 and portion of the opening 56 blocked or closed off by the valve plate 42 depends on the position of the valve plate 42 and particularly on the position of the downstream edge 54 (see FIG. 3 ) of the valve plate 42 . The valve plate 42 may extend completely across the flow passage 40 and cover the entire flow passage 40 , from top to bottom and side to side. On the other hand, the valve plate 42 may be positioned to be parallel and adjacent the sidewall 48 and thereby open the flow passage 40 and opening 56 .
The motion of the movable, hinged valve plate 42 is controlled by a pneumatic or electro-mechanical actuator 62 , such as a pneumatic piston pump. The actuator 62 may have a cylindrical body 64 attached to the side of the flash tank 10 and a reciprocating shaft 66 driven by a piston in the cylindrical body 64 . A distal end of the shaft 66 is pivotable and is attached to the backside of the valve plate 42 . The actuator 62 may extend and retract the shaft 66 to move the valve plate 42 to open the throat area T or close the throat area T of the flow passage 40 . The shaft 66 extends through a port 67 in the sidewall 48 of the inlet nozzle 34 . The port 67 may include a seal to prevent leakage of black liquor.
A controller 68 , e.g., a computer or manual adjustment, determines the extension of the shaft 66 and the position of the valve plate 42 . The controller 68 may extend the shaft 66 to set the position of the valve plate 42 and achieve a desired throat area T for the flow passage 40 . The controller 68 may be adjusted manually to change or adjust the position of the valve plate 42 . Alternatively, the controller 68 may adjust the position of the valve plate 42 by computer, manual adjustment or other suitable means based on, for example, comparison between a desired pressure in the flow passage 40 and a sensed pressure in the flow passage 40 .
Hot black liquor extracted from the screens 20 of a vessel 12 flows through the inlet nozzle 34 and enters the flash tank 10 . The throat area T of the inlet nozzle 34 determines volume of flow or flow velocity using backpressure in the flow passage 40 which restricts the flow of black liquor entering the flash tank 10 . Because the throat area T is determined by the position of the valve plate 42 , the controller 68 can move the valve plate 42 to adjust the throat area T and consequently the velocity or volume of flow through the flow passage 40 .
Controlling the volume of flow or flow velocity in the inlet nozzle 34 allows for the velocity and volume of black liquor entering the flash tank 10 to be regulated, provides a degree of control over the pressure drop in the flash tank 10 and ensures a sufficient pressure in the conduits 26 upstream of the inlet nozzle 34 .
As the black liquor enters the flash tank 10 , the liquor flashes to produce steam 28 and condensate 30 . The steam 28 may be used as heat energy in the vessel 12 , in an impregnation vessel (not shown), in a chip feed bin (not shown), in a chip steaming vessel (not shown), in a tank holding fresh cooking liquor, e.g., white liquor, or other locations in the mill where steam is needed. The condensate 30 may flow to additional flash tanks 10 or other chemical recovery equipment (not shown), e.g., a recovery boiler, an evaporation system or other chemical recovery system.
The orientation of the valve plate 42 in the inlet nozzle 34 is a design choice. The hinge 66 for the valve plate 42 may be attached to either sidewall 48 or the top or bottom walls of the flash tank 10 .
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. | A flash tank including: a closed interior chamber; a gas exhaust port coupled to an upper portion of the chamber; a liquid discharge port coupled to a lower portion of the chamber; an inlet nozzle attached to an inlet port of the chamber, wherein the inlet nozzle includes a flow passage, and a movable valve plate in the flow passage, wherein the valve plate has a first position which defines a first throat in the flow passage and a second position which defines a second throat having a smaller cross-sectional area than the first throat. | 3 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional application of U.S. patent application Ser. No. 09/007,356, filed Jan. 15, 1998, entitled "Slurry Preform System", now U.S. Pat. No. 5,972,169.
BACKGROUND OF THE INVENTION
The present invention relates generally to forming fiber reinforced plastic preforms and, more particularly, to a method and apparatus for controlling fiber deposition in a fiber reinforced preform.
Fiber reinforced plastic (FRP) parts or composite parts are well known and used in a wide variety of applications. An FRP part generally consists of a plastic shape in which carbon, fiberglass, or other reinforcing fibers are dispersed in order to provide strength to the component. One method of making an FRP part is known as resin transfer molding (RTM).
In RTM, fibrous material in a mold is injected with resin which cures to form the part. Examples of these techniques are disclosed in commonly assigned U.S. Pat. No. 4,740,346--Perimeter Resin Feeding of Composite Structures; U.S. Pat. No. 4,849,147--Method of Making a Molded Structure Having Integrally Formed Attachment Members; and U.S. Pat. No. 4,863,771--Hollow Fiber Reinforced Structure and Method of Making Same, each of which is hereby specifically incorporated by reference. In RTM, fibrous material is often formed into a preliminary shape before being placed into the mold. The shaped sections generally conform to the contour of adjacent mold die surfaces and are known as preforms. Preforms have been constructed using several different manufacturing approaches. One such approach is to direct chopped fibers by means of a flow of air onto a screen. One problem with this technique is that it is difficult to obtain desired fiber orientation. Another method utilizes mats of fibrous material to make the preforms. This method, however, produces undesirable amounts of scrap material and is labor intensive, thus resulting in production cost inefficiencies.
Still another technique, known as a wet slurry process, is disclosed, for example, in Keown et al. ("Wet Slurry Process Brings Precision To Reinforced Plastics"). Keown discloses a slurry containing chopped fibers drawn by vacuum into a chamber covered by a screen. As a result, the fibers are deposited on the screen. This approach, however, is associated with certain disadvantages. For example, it is difficult to consistently obtain the desired fiber orientation and compactness of the fibers using this equipment. In addition, the pumps and other equipment required to create the vacuum and draw the slurry through the screen may be unduly complex and difficult to maintain. Furthermore, the process is relatively slow.
An improved wet slurry process is disclosed in commonly assigned U.S. Pat. No. 5,039,465--Method and Apparatus For Forming Fiber Reinforced Plastic Preforms From a Wet Slurry, which is also hereby incorporated by reference. The process disclosed therein teaches creating a preform by raising a screen through a tank containing a slurry of fibers resulting in the fibers being deposited on the screen. While this approach is promising, it also has some drawbacks. For example, structural integrity of the preforms may be compromised as the screen is raised out of the liquid. As long as the screen is moving beneath the surface of the slurry, pressure from the slurry forces the fibers on the screen and holds them in position. However, as soon as the screen breaks the plane of the top of the slurry as the preform is being removed from the tank, the liquid and fiber mixture surrounding the screen tends to rush into the interior cavity of the preform. As the slurry rushes into the preform, the upright side walls of the preform may collapse thereby creating a need for costly repair work or discard of the entire preform. Another challenge in the construction of fiber reinforced preforms is that of maintaining uniform wall thickness throughout the preform. While drawing the screen through the slurry, more liquid is forced through the major surface of the screen that is perpendicular to the direction of draw than the upright side walls that are parallel to the direction of movement of the screen. Because the quantity of fiber deposited on the screen is proportional to the amount of liquid forced through the screen, preforms constructed in this manner may contain sections of non-uniform thickness.
SUMMARY OF THE INVENTION
Pursuant to the present invention, an efficient, low cost method and apparatus for controlling fiber deposition in a fiber reinforced preform is provided.
In one embodiment, a main screen is placed in a tank filled with liquid. The main screen has a major surface, upright side walls and a plurality of openings formed therein. Reinforcing fibers are added to the liquid to create a slurry. The main screen is raised through the slurry to a level beneath the top of the slurry, thereby causing the reinforcing fibers to be deposited on the main screen. A retainer screen is inserted into the slurry such that the reinforcing fibers are sandwiched between the main screen and the retainer screen. Both the main screen and retainer screen are raised out of the tank effectively forming a fiber reinforced preform with minimal deformation.
In another embodiment, the apparatus includes a choke screen positioned adjacent the main screen to reduce the flow of liquid through that portion of the main screen as it is being drawn through the slurry. In order to optimize preform wall thickness, the choke screen may have openings formed therein which are offset in location or different in size from the openings in the main screen.
In another embodiment, a work cell is provided that includes a turntable disposed between the slurry tank and a furnace for efficiently mass producing the preforms.
In another embodiment, the apparatus includes a bubbler control device and separate bubbler zones. The control device is capable of sequencing bursts of air at varying pressures and durations for each of the bubbler zones. Uniformity of the slurry may be maximized by utilizing certain bubbler control sequences depending on the geometry of the preform.
In still another embodiment, the apparatus includes a fiber dispenser for controlling the addition of different types of fibers to the slurry. The fiber dispenser regulates the addition of various fibers in sequence timed to correspond with raising the main screen through the tank. By adding different types of fibers to the slurry during the upstroke of the main screen, a composite preform whose cross-section consists of different layers of materials may be constructed.
BRIEF DESCRIPTION OF THE DRAWINGS
The various advantages of the present invention will become apparent to one skilled in the art after reading the following specification and by reference to the drawings in which:
FIG. 1 is a perspective view of a work cell for creating fiber reinforced preforms from a wet slurry constructed in accordance with the teachings of the present invention;
FIG. 2 is an enlarged side view of the tank station along with the pallet transfer mechanism located directly above the tank and also translated outside the gantry frame shown in phantom;
FIG. 2A is an overhead view of the tank showing the bubbler zone controller;
FIG. 3 is an enlarged top view of the tank station with the pallet and pallet transfer mechanism located over the tank;
FIG. 4 is a side view of a portion of the pallet transfer mechanism with inner carriage pins extended;
FIG. 5 is a side view of a portion of the tank station showing an outer carriage pin and a tank pin engaged with a transfer block;
FIG. 6 is a partial sectional view of the work cell partially broken away to illustrate the order of operations;
FIG. 7 is a partial sectional view of the work cell showing the pallet rotated beneath the pallet transfer mechanism;
FIG. 8 is a partial sectional view of the work cell showing the transfer mechanism extending downward to engage the pallet;
FIG. 9 is a partial sectional view of the work cell showing both inner and outer carriage pins in an extended position;
FIG. 10 is a partial sectional view of the work cell showing carriage and pallet assembly lifted from the plane of the turntable;
FIG. 11 is a partial sectional view of the tank station showing the pallet transfer mechanism as translated above the tank station;
FIG. 12 is a partial sectional view of the tank station showing pallet lowered to engage the wash plate;
FIG. 13 is a partial sectional view of the tank station showing outer carriage pin retracted and tank pin expended, thereby connecting pallet with the wash plate;
FIG. 14 is a partial sectional view of the tank station showing the ball screws actuated in a downward motion to position the main screen at the bottom of the tank;
FIG. 15 is a partial sectional view of the tank station showing ball screws actuated in an upward motion drawing the screen through the slurry while the carriage is lowering the retainer screen into the slurry;
FIG. 16 is a partial sectional view showing tank pins retracted and outer carriage pins extended and retainer screen guide rod seated on retaining screen mounting blocks;
FIG. 17 is a partial sectional view showing retraction of the carriage and pallet assembly;
FIG. 18 is a partial sectional view showing the retainer screen, main screen, and auxiliary screen;
FIG. 19 is a side view showing the fiber dispenser system with a first set of fibers entering the slurry; and
FIG. 20 is a side view showing the fiber dispenser system with a second set of fibers entering the slurry.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A. Summary
Referring to FIG. 1, a work cell 10 for creating a fiber reinforced preform 12 from a wet slurry is shown. Work cell 10 consists of four stations including a tank station 14, a turntable 16, a furnace 18 and a cooling station (not shown). Turntable 16 is positioned within work cell 10 such that parallel rails 20 of tank station 14 extend over turntable 16 thereby providing overhead support for a pallet transfer mechanism 22. Furnace 18 is positioned adjacent turntable 16 to afford easy and efficient transfer of a pallet 24 between turntable 16 and furnace 18.
Generally speaking, the process of creating fiber reinforced preforms begins by loading pallet 24 onto turntable 16, as shown in FIGS. 1 and 6. Mounted to pallet 24 is main screen 26, contoured in the shape of the component ultimately to be formed, having upright side walls 28, major surface 30, and a plurality of openings 32 therein. Retainer screen 34 is shaped to conform to at least the upright side wall portion 28 of main screen 26 and may conform to the entire contour of main screen 26 as shown in FIG. 6.
As shown in FIGS. 2 and 6-11, pallet transfer mechanism 22 is utilized to lift pallet 24 from turntable 16, translate the pallet from a position above turntable 16 to a position above a tank 36, and lower pallet 24 into tank 36. Referring to FIGS. 11-14, pallet 24 is disconnected from pallet transfer mechanism 22 and subsequently connected to wash plate 38. Wash plate 38 may be raised up and down within tank 36 by rotation of ball screws 40. Reinforcing fibers 42 and liquid 44 are added to tank 36 to create a slurry 45. Slurry 45 is mixed utilizing a mechanical stirring device or by a bubbler as discussed in commonly assigned U.S. Pat. No. 5,039,465, which is hereby incorporated by reference.
As shown in FIG. 2A, one embodiment of the present invention includes a bubbler zone controller 86 for regulating the supply of fluid, preferably air, sent to plurality of bubbler zones 88. Tank 36 is divided into at least two, but preferably four, bubbler zones 88, denoted A, B, C, and D. Air source 90 is connected to plurality of supply lines 92 located upstream of bubbler valves 94, 96, 98 and 100. In a portion of a typical sequence of operation, bubbler zone controller 86 commands bubbler valve 94 to open allowing air to pass to bubbler zone A. The air supplied to bubbler zone A escapes through plurality of openings 102 thereby mixing slurry 45 in zone A.
In standard operating mode, air pulses are sent to bubbler zones 88 in a certain sequence to assure a random mixing of slurry 45. For example, zone A and zone C are sent air for 3 seconds while zones B and D are turned off. Zones B and D are then activated for 3 seconds while zones A and C are off. This cycle repeats until preform 12 is removed from slurry 45. Without the use of the bubbler zone controller in its standard operating mode, a vortex forms in slurry 45 as main screen 26 is raised through tank 36. Depending on the geometry of preform 12, a vortex may be detrimental to the structural integrity of preform 12 because the swirling motion of slurry 45 washes reinforcing fibers 42 from upright side walls 28. On the other hand, in instances where preform 12 has little or no upright sidewall 28, a vortex is helpful in that it assists in sweeping reinforcing fibers 42 off of wash plate 38 and into main screen 26. In these cases, a vortex may be initiated by pulsing air into bubbler zones A through D in sequence of alphabetical order.
Referring now to FIGS. 15-17, pallet 24 including main screen 26 is initially lowered near the bottom of tank 36. Pallet 24 is then drawn upwards through tank 36 thereby forcing liquid 44 through plurality of openings 32 and depositing reinforcing fibers 42 upon main screen 26. Prior to main screen 26 breaking the plane of the surface of slurry 45, retainer screen 34 is inserted into slurry 45 such that reinforcing fibers 42 are sandwiched between main screen 26 and retainer screen 34. Retainer screen 34 is positioned to protect preform 12 from damage due to slurry 45 rushing over upright side walls 28 as main screen 26 is lifted out of slurry 45. Once retainer screen 34 is in place, both main screen 26 and retainer screen 34 are raised together out of slurry 45 by pallet transfer mechanism 22. As shown in FIGS. 1 and 2, pallet transfer mechanism 22 translates pallet 24 from above tank 36 to a position above turntable 16. Pallet 24 is lowered back onto turntable 16 in route to furnace 18. Turntable 16 is rotated 180° about an axis 46 to bring pallet 24 within close proximity of furnace 18. Any suitable transfer mechanism may be utilized to unload pallet 24 from turntable 16 and into furnace 18. Pallet 24 including main screen 26, retainer screen 34 and preform 12 is heated in furnace 18 to evaporate as much liquid 44 trapped between reinforcing fibers 42 as possible. Heated pallet 24 is then transferred to the cooling station, not shown, where air is forced through main screen 26, retainer screen 34 and preform 12 to cool pallet 24 and evaporate any remaining liquid 44. Retainer screen 34 is removed to provide access to preform 12 which is subsequently removed as one contiguous component.
As shown in FIG. 18, an alternative embodiment of the invention includes an auxiliary screen 82 positioned beneath at least a portion of main screen 26. Auxiliary screen 82 acts as a choke effectively reducing the amount of liquid 44 forced through the plurality of openings 32 in main screen 26. The choke serves to divert the flow of liquid 44 such that the amount of liquid passing through major surface 30 is approximately equal to that of the amount of liquid 44 passing through upright side walls 28. Because the quantity of reinforcing fibers 42 deposited on main screen 26 is proportional to the amount of liquid 44 allowed to pass through the plurality of openings 32, equal flow rates of liquid 44 through different portions of main screen 26 will produce a preform 12 of substantially uniform wall thickness. Auxiliary screen 82 also has a plurality of openings 84 which may be shaped, sized or positioned differently than the plurality of openings 32 in main screen 26 as long as auxiliary screen 82 restricts the flow of liquid 44 through main screen 26. One example of auxiliary screen 82 constructed per the present invention utilizes the plurality of openings 84 in auxiliary screen 82 positioned in misalignment relative to the plurality of openings 32 within main screen 26. This misalignment is purposeful to provide a tortuous path for liquid 44 to follow, thereby choking the flow of liquid 44 through main screen 26.
Another embodiment of the invention, shown in FIGS. 19 and 20, includes a fiber dispenser controller 104 for introducing more than one type of fiber into slurry 45. Depending on the final component to be created, dispenser controller 104 regulates the quantity of a first set of fibers 106 to be added to slurry 45. Dispenser controller 104 acts in concert with the mechanism utilized to draw main screen 26 through tank 36 such that first set of fibers 106 is added when main screen 26 is near the bottom of tank 36. As main screen 26 is raised through slurry 45, first set of fibers 106 forms the first layer of preform 12. As shown in FIG. 20, main screen 26 continues to rise through slurry 45 while fiber dispenser controller 104 closes off the supply of first set of fibers 106 and introduces a second set of fibers 108 into slurry 45. The addition of fibers with different characteristic physical properties such as fiber length, fiber diameter, chemical composition, tensile strength and conductivity in this manner produces a stratified preform 12 that may be custom tailored to a final application.
For example, components that require only one aesthetically pleasing exterior surface, such as an oil pan or housing cover, may be constructed using a cosmetically appealing material on that surface alone while the remaining layers of the structure comprise a less costly material. Similarly, component impact resistance may be optimized by incorporating layers of fibers with different tensile strengths into preform 12. If high bending strength and low cost are required, a multiple layered composite with at least three layers may be specifically designed to meet those needs in a cost effective manner. The outside layers would be constructed from higher strength fibers while the lower stress center layers would consist of lower strength, lower cost fibers. Another example showcasing the versatility of this invention includes a component with a layer of high electrical conductivity among layers of material with lower electrical conductivity. This objective may be achieved by using a set of fibers with high electrical conductivity or by addition of particles with high electrical conductivity to one of the fiber supply bins 110.
B. Details of Apparatus and Method
To further assist the reader, the preferred apparatus and method are now described in further detail. In reference to FIGS. 1 and 6, pallet 24 includes main screen 26 having upright side walls 28, major surface 30, and a plurality of openings 32 therein, positioned in an aperture 48 of a mask 50. The inner portion of mask 50 defining aperture 48 is provided with an offset surface 52 allowing an extending lip 54 of main screen 26 to fit flush with a planar surface 56 of mask 50. Guide rods 58 are attached to retainer screen 34. Retainer screen mounting blocks 60 are secured to mask 50 and are designed in such a manner as to position retainer screen 34 relative to main screen 26 once guide rods 58 engage retainer screen mounting blocks 60.
To facilitate movement of pallet 24 from turntable 16 to tank 36, transfer blocks 62 are also fixedly mounted to mask 50. As shown in FIG. 5, each transfer block 62 contains upper aperture 64 and lower aperture 66. As shown in FIGS. 1, 3 and 5, upper apertures 64 are oriented to cooperate with outer carriage pins 68 mounted to a carriage 70. Once outer carriage pins 68 have engaged upper apertures 64, pallet 24 may be lifted using carriage 70 in conjunction with a hydraulic ram 72. Hydraulic ram 72 is capable of raising and lowering carriage 70 relative to turntable 16 and tank 36. Carriage 70 and hydraulic ram 72 may be translated from a position above turntable 16 to a position above tank 36 and back again by utilizing parallel rails 20 of tank station 14.
In reference to FIGS. 1 and 7-9, turntable 16 is rotated about axis 46 such that main screen 26 is positioned beneath carriage 70. Carriage 70 is lowered into position by extension of hydraulic ram 72. Outer carriage pins 68 are extended to engage the upper apertures 64 of transfer blocks 62. FIG. 4 shows inner carriage pins 74 extended beneath guide rods 58 to support the weight of retainer screen 34. As shown in FIGS. 1, 2 and 10-12, carriage 70 and pallet 24 are now sufficiently interconnected to lift pallet 24 from turntable 16. Carriage 70 along with pallet 24 is translated along parallel rails 20 into position over tank 36. Hydraulic ram 72 is actuated once again to lower carriage 70. Wash plate 38 is attached at four locations to individual ball screws 40 which are in turn mounted to a gantry frame 76. The position of wash plate 38 within tank 36 is controlled utilizing ball screws 40. As shown in FIGS. 5 and 12, carriage 70 is lowered until mask 50 engages offset surface 77 of wash plate 38. Once mask 50 is seated, surface 56 is substantially coplanar with upper planar surface 78 of wash plate 38. As shown in FIGS. 13 and 14, outer carriage pins 68 are retracted, thereby disengaging main screen 26 from carriage 70. Fixedly mounted to wash plate 38, tank pins 80 are extended to engage lower apertures 66 of transfer blocks 62. Main screen 26 is lowered into tank 36 by actuating ball screws 40. While main screen 26 is being lowered into tank 36, hydraulic ram 72 holds carriage 70 stationary. Retainer screen 34 is held partially above slurry 45 by inner carriage pins 74.
As shown in FIGS. 15-17, preform 12 is created by drawing main screen 26 through slurry 45 at a rate that causes the liquid to pass through the openings in main screen 26, thereby depositing reinforcing fibers 42 on the surface of main screen 26. As main screen 26 is being raised, hydraulic ram 72 is actuated in a downward motion to insert retainer screen 34 into slurry 45. Ball screws 40 continue to raise main screen 26 until retaining screen mounting blocks 60 engage guide rods 58. At this time, tank pins 80 are retracted, thereby disconnecting wash plate 38 from carriage 70. Outer carriage pins 68 are extended to once again engage the upper apertures 64 of transfer blocks 62. Hydraulic ram 72 is actuated to lift carriage 70 along with main screen 26 and retainer screen 34. Carriage 70 translates via parallel rails 20 to its original position above turntable 16.
Referring once again to FIG. 1, carriage 70 is lowered via hydraulic ram 72 onto turntable 16. Both inner and outer carriage pins, 74 and 68, respectively, are retracted effectively disconnecting the carriage from screens 26 and 34. Carriage 70 is raised out of the way via hydraulic ram 72. Turntable 16 is rotated 180° about axis 46 to facilitate unloading of pallet 24 from turntable 16 and into furnace 18 or any other suitable drying device. Pallet 24 is transferred to cooling station, not shown, where a fan is used to draw air through preform 12 and screens 26 and 34. Once screens 26 and 34 have cooled, retainer screen 34 is lifted off and preform 12 may be removed. Preform 12 is now suitable for further conventional processing such as RTM in order to form a final component.
The foregoing discussion discloses and describes exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims. | An efficient, low cost method and apparatus for controlling fiber deposition in a fiber reinforced preform is provided. In the method, a main screen is placed in a tank filled with liquid. The main screen has a major surface, upright side walls and a plurality of openings formed therein. Reinforcing fibers are added to the liquid to create a slurry. The main screen is raised through the slurry to a level beneath the top of the slurry, thereby causing the reinforcing fibers to be deposited on the main screen. A retainer screen is inserted into the slurry so that the reinforcing fibers are sandwiched between the main screen and the retainer screen. Both the main screen and retainer screen are raised out of the tank effectively forming a preform with minimal deformation. An alternative embodiment includes a bubbler zone control device for mixing the slurry. The tank is divided into separate areas or zones whereby the supply of fluid to each bubbler zone is controlled. The bubbler zone controller may be used to initiate or diminish a vortex in the slurry as the screen is being raised out of the tank. Another embodiment includes a fiber dispenser controller for sequentially adding different fibers to the slurry. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of co-pending (and now allowed) U.S. patent application Ser. No. 12/563,490, filed Sep. 21, 2009 and entitled “RADIAL BEARINGS FOR DEEP WELL SUBMERSIBLE PUMPS”.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to bearings for use in deep well submersible pump systems, and more particularly to such bearings used to transmit radial loads and that are exposed to high temperature fluids being pumped by submersible pump systems.
[0003] Deep-well submersible (DWS) pumping systems (also referred to as electric submersible pumps (ESP)) are especially useful in extracting valuable resources such as oil, gas and water from deep well geological formations. In one particular operation, a DWS pump unit can be used to retrieve geothermal resources, such as hot water, from significant subterranean depths. In a conventional configuration, a generally centrifugal pump section and a motor section that powers the pump section are axially aligned with one another and oriented vertically in the well. More particularly, the motor section is situated at the lower end of the unit, and drives one or more pump section stages mounted above.
[0004] Because DWS pumping systems are relatively inaccessible (often completely submerged at distances between about 400 and 700 meters beneath the earth's surface), they must be able to run for extended periods without requiring maintenance. Such extended operating times are especially hard on the bearings that must absorb radial and axial forces of the rotor that is used to transmit power from the motor section to the impellers of the pump section. Radial bearings are one form of bearings employed in DWS systems, and are often spaced along the length of the rotor, particularly in a region where two axially adjacent rotor sections (such as between adjacent pump bowls in a serial multi-bowl assembly) are joined. These bearings are generally configured as sleeve-like sliding surfaces that are hydro dynamically lubricated between the surfaces by a contacting liquid. In one form, radial bearings in the pump section are situated in bowls that are lubricated by the fluid being pumped, while radial bearings in the motor section are lubricated by a coolant used to fill portions of the motor housing. For motors used in geothermal applications, the motor section lubricant is typically oil.
[0005] Conventional radial bearings for submersible DWS systems are not configured to withstand the high operating temperatures and pressures associated with the DWS environment, and as such have been prone to early failure. For example, in situations involving geothermal wells, the water being extracted from the earth may be 120 to 160 degrees Celsius or more, making the job of an on-board coolant (whether it be oil-based or water-based) all the more difficult. In addition, any impurities in the water that come in contact with the bearing surfaces of the pump section could leave deposits that may contribute to premature bearing wear or other operability problems. The problem is also particularly acute in the motor section, where radial bearing are generally not configured to guide or otherwise introduce sufficient motor cooling fluid into the bearing contact surface to promote adequate lubrication, especially at the elevated temperatures experienced inside the DWS motor section. That the hydrodynamic properties of the bearing need to be maintained not only in high temperature environments where the lubricating liquid has low viscosity, but also during start-up and shut-down phases of motor operation when the lubricating liquid generally is highly viscous (or not even present) exacerbates the design challenges. As such, there exists a desire for a bearing suitable for operation in deep well environments.
BRIEF SUMMARY OF THE INVENTION
[0006] These desires are met by the present invention, where bearings for use in geothermal and related deep well environments are disclosed. In accordance with a first aspect of the invention, a bearing assembly for use in a DWS pump is disclosed. The assembly includes a bearing housing that can be attached to or formed as part of the pump, a sliding bearing positioned within the housing and a fluid conveying mechanism, where at least the bearing is rotatably positioned within the housing. The fluid conveying mechanism is configured to deliver a lubricant between a multilayer bushing and a bearing sleeve that make up the sliding bearing. In this way, a chamber that encompasses at least the sliding bearing defines a substantially continuous lubricating environment between the sleeve and bushing, capable of providing lubrication in both hot and cold environments, as well as during pump startup, in addition to other operating conditions. The bushing is of a multilayer construction, and is disposed against an inner surface of the housing. The bearing sleeve is concentrically disposed within the multilayer bushing and cooperative with it such that the sleeve rotates relative to the bushing.
[0007] Optionally, the multilayer bushing is made up of one or more metal layers and a layer of a non-metal that can be used to coat or otherwise cover the one or more metal layers. In a more particular form, the non-metal layer is made up of an electrically nonconductive material that forms an outermost layer of the multilayer bushing. In an even more particular form, the electrically nonconductive material is polyaryletheretherketone (PEEK) or a related engineered material. In another form, a plurality of metal layers can be used, where such layers may include a galvanized tin layer, a bronze layer and a steel layer. One particular form of the fluid conveying mechanism is a shaft-mounted conveying screw and a housing-mounted conveying screw cooperative with one another to define a lubricant pumping passage between them. In this way, the shaft-mounted conveying screw rotates in response to the turning of the shaft to act as a lubricant-pumping device that can produce an increase in pressure in the lubricant such that the lubricant squeezes between the adjacent bushing and bearing sleeve surfaces. In an even more particular embodiment, the multilayer bushing is made up of numerous metal layers surrounded with an outermost layer of an electrically nonconductive material (such as the aforementioned PEEK). In another option, the bearing is constructed so that it can operate in high temperature operating environments, where the temperature of a fluid being pumped by the DWS is at least between 120° and 160° Celsius, for example, such as those commonly found in deep well geothermal applications.
[0008] According to another aspect of the invention, a DWS pump is disclosed. The pump includes a motor section, a pump section and a bearing assembly coupled to at least one of the motor and pump sections. The bearing assembly includes a bearing sleeve, a bushing and a fluid conveying mechanism. The bearing sleeve is cooperative with a shaft to transfer radial loads from the shaft to a pump housing, while the bushing cooperates with the bearing sleeve to define a lubricant flow path between them. The bushing includes a multilayer construction with at least one of the layers comprising metal. The material use and construction of the bearing and the bushing is such that they can operate in a substantially continuous high temperature environment, where for example, the fluid being pumped is at least between 120° and 160° Celsius. The fluid conveying mechanism is designed to be in fluid communication with the bearing sleeve and the bushing during pump operation. In this way, the fluid conveying mechanism receives a lubricant from a lubricant source. The fluid conveying mechanism operates to pressurize the lubricant such that it flows between the multilayer bushing and the bearing sleeve to achieve the substantially continuous lubrication of the bearing sleeve and bushing during startup and subsequent operation of the pump. In one form, the source of lubricant is self-contained so that once the lubricating fluid has been passed through the interstitial-like region defined between the sleeve and bushing, it can be recirculated for reuse. In addition to the shaft mentioned above, the motor section is made up of a stator configured to receive electric current from a source of electric power and a rotor inductively responsive to an electromagnetic field established in the stator. Likewise, the pump section, in addition to the inlet and outlet, is made up of at least one impeller rotatably coupled to the shaft such that pressurization of the fluid being pumped from the deep well moves the fluid from the fluid inlet to the fluid outlet.
[0009] Optionally, the one or more metal layers of the multilayer bushing are made up of numerous metal layers at least one of which is steel. In a more particular form the layers may include a galvanized tin layer disposed on the inner surface of the radial bearing, a bronze layer disposed around the galvanized tin layer and the steel layer disposed around the bronze layer. Even more particularly, the bushing includes an outermost (i.e., top) layer of electrically non-conductive material disposed on the outer surface of the radial bearing. Such electrically non-conductive material may be PEEK or some related structurally-compatible material. In a particular form, the fluid conveying mechanism may include a shaft-mounted conveying screw and a housing-mounted conveying screw cooperative with one another to define a rotating lubricant pumping passage between them. In situations where the motor section employs one or more of the radial bearing assemblies, the bearings making up the assembly can be lubricated by an oil that can also serve as a coolant for the motor. Likewise, in situations where the pump section employs one or more radial bearing assemblies, such assemblies can be configured to be lubricated by the geothermal fluid being pumped.
[0010] According to yet another aspect of the invention, a method of pumping a geothermal fluid is disclosed. The method includes placing a DWS pump in fluid communication with a source of geothermal fluid and operating the pump such that geothermal fluid that is introduced into the pump through the inlet is discharged through the outlet. The pump includes a motor, fluid inlet and outlet and one or more impellers. In addition, the pump includes one or more bearing assemblies that have a bearing sleeve and a bushing cooperative with one another to define a lubricant pumping flow path between them.
[0011] The bushing is further made of a multilayer construction with at least one of the layers made from a metal. The bearing assembly further includes a pressurizing device (such as a conveying screw, as discussed below) that receives and pressurizes a fluid that can be used as a lubricant, forcing it to flow between the multilayer bushing and the bearing sleeve. In this way, a substantially continuous liquid environment is formed between the components of a bearing assembly by the pressurizing device during operation of the pump. Such liquid being pressurized for use in the motor is preferably an oil (which, in addition to performing lubricating functions, also works as a coolant and electrical insulation), while such liquid being operated upon by the pump impellers is preferably water from the geothermal source.
[0012] Optionally, the bushing and the bearing sleeve are configured to operate in a high temperature environment, such as a substantially continuous aqueous environment of at least 120° and 160° Celsius. The multilayer construction of the bushing may be made up of numerous metal layers, including dissimilar metal layers. Furthermore, the multilayer construction may include a non-metallic layer. In a preferred form, the non-metallic layer is made from PEEK, which helps perform an insulation function. In a more particular form, the PEEK layer forms the outermost layer of the bushing such that upon cooperation with a complementary inner surface of a bearing housing or related structure, a flow path for pressurized liquid that is pumped from between the bushing and the bearing is created with at least one of the surfaces being made from PEEK. The other layers may be made from steel (which can act as a carrier or housing), bronze (which may function as the main sliding partner cooperative with the rotor), tin (which may serve as a sliding partner to the rotor as a run-in layer during startup. The non-metallic layer may be made from a material that has been engineered to achieve a very low coefficient of static friction.
[0013] Moreover, the method may include mounting (or otherwise securing) a first cooperative pumping mechanism to a static (i.e., non-rotational) portion of the bearing assembly, and mounting or securing a second cooperative pumping mechanism to the shaft. In this way, upon rotation of the shaft, the first and second pumping mechanisms cooperate to achieve the necessary lubricant pressurization. The first and second pumping mechanisms may include threaded surfaces that cooperate to achieve such pressurization. Such threads may, for example, define a generally continuous screw-like spiral shape.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0014] The following detailed description of specific embodiments can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
[0015] FIG. 1 shows a notional geothermal power plant that can utilize a DWS pumping system;
[0016] FIG. 2 shows a DWS pumping system of the power plant of FIG. 1 , including bearing assemblies according to an aspect of the present invention;
[0017] FIG. 3 shows details of one of the bearing assemblies employed in the DWS pumping system of FIG. 2 ;
[0018] FIG. 4 shows an exploded view of some of the components of the bearing assembly of FIG. 3 ;
[0019] FIG. 5A shows a cutaway view of the bushing employed in the bearing assembly of FIG. 3 ; and
[0020] FIG. 5B shows the details of the layers making up the bushing of FIG. 5A .
[0021] The embodiments set forth in the drawings are illustrative in nature and are not intended to be limiting of the embodiments defined by the claims. Moreover, individual aspects of the drawings and the embodiments will be more fully apparent and understood in view of the detailed description that follows.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Referring first to FIGS. 1 and 2 , a geothermal power plant 1 and a DWS pump 100 employing a radial bearing assembly 200 according to an aspect of the present invention is shown. Naturally-occurring high temperature geothermal fluid in the form of water (for example, between approximately 120° C. and 160° C., depending on the source) 5 from an underground geothermal source (not shown) is conveyed to plant 1 through geothermal production well piping 10 that fluidly connects the DWS pump 100 to a heat exchanger (not shown) that converts the high temperature well water into steam. A steam turbine 20 that turns in response to the high temperature, high pressure steam from the heat exchanger. Plant 1 may also include one or more storage tanks 70 at the surface with which to temporarily store surplus water from the underground geothermal source. The turbine 20 is connected via shaft (not shown) to an electric generator 30 for the production of electric current. The cooled down water is routed from the heat exchanger discharge to be sent to the geothermal source through geothermal injection well piping 60 . The electricity produced at the generator 30 is then sent over transmission lines 50 to the electric grid (not shown).
[0023] Referring with particularity to FIG. 2 , the DWS pump 100 is placed within well piping 10 and includes a motor section 105 , a pump section 110 , a fluid inlet section 115 to accept a flow of incoming fluid 5 , and a fluid outlet section 120 that can be used to discharge the fluid 5 to a riser, pipestack or related fluid-conveying tubing. As shown, both the motor section 105 and the pump section 110 may be made of modular subsections. Thus, within pump section 110 , there are numerous serially-arranged subsections in the form of pump bowls 112 A, 112 B, 112 C and 112 D that each house respective centrifugal impellers 110 A, 110 B, 110 C and 110 D. Likewise, although there is only one motor subsection shown, it will be appreciated that multiple such subsections may be included, such as to satisfy larger power demands or the like. The fluid inlet section 115 is situated axially between the motor and pump sections 105 , 110 , and may include a mesh or related screen to keep large-scale particulate out in order to avoid or minimize particulate contact with the rotating components in the pump section 110 . A seal 150 is used to keep the motor section 105 and the pump section 110 fluidly separate, as well as to reduce any pressure differentials that may exist between the motor section lubricant and the pump section lubricant. As stated above, the temperature of the fluid 5 is typically between approximately 120° C. and 160° C.; however, even at that temperature, the water will remain in a liquid state due to the high surrounding pressure inherent in most geothermal sources. Moreover, because the operating temperature of the motor section is higher than that of the extracted fluid 5 , any heat exchange between the flowing fluid 5 and the outer surfaces of motor section 105 tends to cool the motor section 105 and the various components within it.
[0024] Motor section 105 has a casing, outer wall or related enclosure 105 C that is preferably filled with oil or a related lubricant (not shown) that additionally possesses a high dielectric strength and thermally insulative properties to protect the various induction motor windings, as well as provide lubrication to the motor bearings. By such construction, the motor internal components are fluidly isolated from the pumped geothermal well water. Heat generated within the motor section 105 is efficiently carried by the internal oil to the enclosure 105 C, where it can exchange heat with the water being pumped that passes over the outside of the enclosure 105 C. Because the lubricant inside the enclosure 105 C is of a high temperature (for example, up to about 200° C.), the motor bearings (not shown) must be designed for such temperatures, with an operating lifetime of about 40,000 hours over about 250 motor start-ups. The predicted revolutions range of DWS pump 100 is between about 1,800 revolutions per minute and about 3,600 revolutions per minute. As stated above, the lubricant used inside the enclosure 105 C of the motor section 105 is fluidly isolated from the pump section 110 . Thus, absent a complex piping scheme (not employed herein), the oil contained within the enclosure 105 C of motor section 105 cannot be routed to other locations within the pump 100 . As such, another fluid 5 , such as the well water being pumped, must be used to provide lubrication of the bearing assembly 200 (discussed below). This can lead to configurational simplicity in that the fluid being pumped from the deep well can serendipitously be used to perform the hydrodynamic function required by the bearing assembly 200 . Nevertheless, such a configuration means there is a reduced opportunity to provide cooling to the bearing assembly 200 in the motor section 105 , as well as to provide ample bearing lubrication during DWS pump 100 startup conditions.
[0025] A shaft, which includes a motor shaft section 125 A and a pump shaft section 125 B, extends over the length of DWS pump 100 . The motor shaft section 125 A extends out of the upper end of the motor section enclosure 105 C, and is fluidly isolated between the motor and pump sections 105 and 110 by the aforementioned seals 150 . Motor shaft section 125 A is connected by a coupling 175 to pump shaft section 125 B which is surrounded by and frictionally engages numerous bearings, including the radial bearing assembly 200 that is used to transmit normal loads (i.e., those perpendicular to the axial dimension of shafts 125 A and 125 B) from shaft eccentricities or the like to the remainder of the DWS pump 100 , thereby reducing the impact of shaft wobbling on other components. The bearing assembly 200 , as well as various other bearings (such as the ones housed in the pump section 110 ), are spaced along the length of shaft 125 at rotor dynamically advantageous locations. It will be understood by those skilled in the art that the number of radial bearings may vary according to the number of adjacently-joined shaft members, or other criteria. The present bearing assembly 200 is considered to be radial in nature because of its ability to carry radial (rather than thrust or related axial) loads, which are commonly transmitted through roller, tapered or related thrust-conveying mechanisms that are not discussed in further detail.
[0026] Motor section 105 includes an induction motor (for example, a squirrel-cage motor) that includes a rotor 105 A and a stator 105 B that operates by induction motor and related electromagnetic principles well-known to those skilled in the art. As will be additionally understood by those skilled in the induction motor art, stator 105 B may further include coil winding 106 and a laminate plate assembly 107 . As will be further understood by those skilled in the induction motor art, motor section 105 may be made from numerous modular subsections (with corresponding rotors 105 A and stators 105 B) axially coupled to one another. Electric current is provided to stator 105 B by a power cable 130 that typically extends along the outer surface defined by enclosure 105 C. Power cable 130 is in turn electrically coupled to a source. Operation of motor section 105 causes the motor shaft section 125 A and pump shaft section 125 B of the shaft that is coupled to the rotor 105 A to turn, which by virtue of the pump shaft section 125 B connection to the one or more serially-arranged centrifugal impellers 110 A, 110 B, 110 C and 110 D in the pump section 110 turns them so that a fluid (such as the high temperature water resident in the geothermal source and shown presently as the serpentine line 5 in the upper right of the flow path of the pump section 110 ) can be pressurized and conveyed to the power plant 1 on the earth's surface. A check valve 120 A can be situated in the fluid outlet section 120 that is fluidly connected to and downstream of the pump section 110 . Flanged regions 140 are used to couple the various sections 105 and 110 together. Such flanged regions 140 may be secured together using bolted arrangement or some related method known to those skilled in the art.
[0027] Referring next to FIGS. 3 and 4 , the radial bearing assembly 200 is shown (in FIG. 3 ) with its major components in exploded form (in FIG. 4 ). As discussed above, each of the motor section 105 and the pump section 110 of DWS pump 100 may be made up of numerous subsections, with such number dictated by the pumping requirements of the application. More particularly, within motor section 105 the number of stators 105 B that can be made to cooperate with rotor or rotors 105 A is commensurate with the power requirements of the DWS pump 100 . In such a multiple stator configuration, each stator 105 B within motor section 105 would have two radial bearing assemblies 200 , arranged as substantial minor images of one another on opposing axial ends of the stator 105 B.
[0028] Assembly 200 includes a housing 210 that can be matingly connected to an appropriate location on the motor section 105 of DWS pump 100 . In one form, a flange 211 forms part of the housing 210 and includes numerous apertures 211 A formed therein; some of the apertures 211 A can be used in conjunction with bolts or related fasteners to establish a flanged and bolted relationship, while others can be used as backflow holes for any cooling fluid (not shown). Other larger versions 211 B of the apertures are situated radially inward and can be used as a passageway for electrical wire and related power cables. In one form, the flanged relationship between adjacent housings 210 may be effected by connection to flanged region 140 that is depicted in FIG. 2 . The housing 210 also includes an axially-extending outer wall 212 that defines a generally smooth sleeve-like inner surface that is sized to form a tight fit (for example, a shrink fit or press-fit between the radial bearing housing 210 with a corresponding outer surface of a bushing 220 that together with a bearing sleeve 230 forms a part of radial bearing assembly 200 that transmits loads between the shaft 125 and the remainder of the DWS pump 100 . The bearing sleeve 230 is sized to fit within the bushing 220 such that the outer surface of bearing sleeve 230 is in close cooperation with the inner surface of bushing 220 . In this way, when assembled, the housing outer wall 212 , the bushing 200 and the bearing sleeve 230 exhibit a nested or concentric relationship with one another.
[0029] Lubricant is forced between the bearing sleeve 230 and bushing 220 by a dual screw pump 240 that is made up of a housing screw 240 A and a shaft screw 240 B. As stated above, the lubricant being pumped is preferably oil contained within the motor section so that it is fluidly decoupled from the geothermal water being moved by DWS pump 100 . The outer surface of shaft screw 240 B and the inner surface of the housing screw 240 A have continuous threads 245 formed on them. The threads 245 from each of the screws 240 A, 240 B mesh together upon assembly to define a positive-displacement screw conveyor with one or more lubricant pumping passages that pressurize an incoming fluid I (shown in FIG. 3 ) to force it along the axial dimension of the interstitial space between bushing 220 and the bearing sleeve 230 , after which it is output, indicated at O in FIG. 3 . Apertures 225 formed between flange 211 and the housing outer wall 212 provide a lubricant flow path that is used to feed lubricant from a lubricant supply (not shown) to the screw pump 240 .
[0030] The dual conveying screws 240 A and 240 B of the radial bearing assembly 200 take the lubricating fluid used in motor section 105 and compress it to ensure reliable and sufficient lubrication between the bearing sleeve 230 and the bushing 220 . Specifically, screw 240 B rotates while conveying screw 240 A remains stationary. In this way, the radial bearing assembly 200 operates with a significant reduction in friction not only during operation of the DWS pump 100 in high temperature environments, but also during the start-up and shut-down phases, thereby taking full advantage of their hydrodynamic properties. Further, the positioning of the dual conveying screws 240 A and 240 B in front of the bushing 220 and bearing sleeve 230 may increase the radial load capacity of the radial bearings. Specifically, the radial bearing assembly 200 creates head due to the load and speed in the lubrication gap formed between the bearing sleeve 230 and the bushing 220 . Because of the additional heat, the viscosity of the lubricating fluid drops, which causes a reduction in the lubrication film thickness and a concomitant decrease the load capacity. This can be compensated for by increasing the flow through the radial bearing assembly 200 , which acts to help the assembly stay cooler, which in turn results in a higher viscosity in the lubrication film. Also, it is contemplated that for operating the motor with a variable frequency drive, the bearings may be coated with a thin layer of an electrical insulation material having excellent mechanical properties on the fitting diameter.
[0031] Referring next to FIGS. 5A and 5B , a cutaway view of the bushing 220 ( FIG. 5A ) and its multilayered construction ( FIG. 5B ) are shown. As can be seen with particularity in FIG. 5B , the innermost layer 220 A (i.e., the one which will engage the outer surface of the bearing sleeve 230 ) is made from a galvanized tin, preferably between about a couple of micrometers thick. Directly underneath that is a bronze layer 220 B that is about 2 millimeters in thickness. Beneath that, a thicker steel housing (preferably 5 millimeters thick) 220 C can be used, itself surrounded by an outermost layer 220 D of an electrically insulative material, such as PEEK or a related structurally suitable polymeric. This is especially beneficial in situations where the motor section 105 is run in a variable frequency drive (VFD) mode of operation, such as between the above-stated 1800 and 3600 RPM. The thickness dimensions of the various layers of FIG. 5B are not necessarily shown to scale. For example, the thickness of the innermost layer 220 A may be (as indicated above) about three orders of magnitude thinner than the bronze layer 220 B.
[0032] It will be appreciated that while the present description focuses primarily on distributing lubricant within a submersible motor such as for a DWS pumping system, the technique can be utilized in a variety of other components and applications above or below the surface of the earth. It is noted that recitations herein of a component of an embodiment being “configured” in a particular way or to embody a particular property, or function in a particular manner, are structural recitations as opposed to recitations of intended use. More specifically, the references herein to the manner in which a component is “configured” denotes an existing physical condition of the component and, as such, is to be taken as a definite recitation of the structural characteristics of the component.
[0033] It is noted that terms like “generally,” “commonly,” and “typically,” when utilized herein, are not utilized to limit the scope of the claimed embodiments or to imply that certain features are critical, essential, or even important to the structure or function of the claimed embodiments. Rather, these terms are merely intended to identify particular aspects of an embodiment or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment. Likewise, for the purposes of describing and defining embodiments herein it is noted that the terms “substantially,” “significantly,” “about” and “approximately” that may be utilized herein represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement or other representation. Such terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.
[0034] Having described embodiments of the present invention in detail, and by reference to specific embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the embodiments defined in the appended claims. More specifically, although some aspects of embodiments of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the embodiments of the present invention are not necessarily limited to these preferred aspects. | A bearing assembly for use in a deepwell submersible pump, the pump and a method of pumping a geothermal fluid. The bearing assembly is constructed to include a lubricant conveying mechanism, a bearing sleeve and a multilayer bushing. The lubricant is forced between the bushing and a bearing sleeve by the lubricant conveying mechanism that cooperates with the rotation of a shaft used to connect a power-providing motor with one or more pump impellers. In this way, there exists a substantially continuous lubricant environment between the sleeve and bushing to act in a hydrodynamic fashion. | 5 |
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
This application is a National Stage Entry of International Application No. PCT/JP2012/000558, filed Jan. 30, 2012. The entire content of the above-referenced application is expressly incorporated herein by reference.
BACKGROUND
The present invention relates generally to a radio communication system and, more specifically, to techniques of control signal transmission in coordinated multi-point (CoMP) transmission/reception schemes.
Recently, LTE (Long Term Evolution)-Advanced standard has been developed for 4th generation system (4G), where the fairly aggressive target in system performance requirements have been defined, particularly in terms of spectrum efficiency for both downlink (DL) and uplink (UL) as indicated in the Sect. 8 of 3GPP TR 36.913 v9.0.0, Requirements for further advancements for Evolved Universal Terrestrial Radio Access (E-UTRA) (LTE-Advanced), December 2009 (hereinafter referred to as “NFL 1”). Considering the target of the cell-edge user throughput and the average cell throughput, which is set to be roughly much higher than that of LTE Release 8 (Rel. 8), multiple techniques, such as carrier aggregation, downlink enhanced MIMO, coordinated multi-point transmission/reception (CoMP), have been included in LTE-Advanced.
In Rel. 8/9/10, the downlink control channel (PDCCH) is defined to send control signal in Sect. 6.8 of 3GPP TS 36.211 v10.3.0, Physical Channels and Modulation for Evolved Universal Terrestrial Radio Access (E-UTRA) (Release 10) (hereinafter referred to as “NPL2”). Each UE's downlink control information (DCI) is aggregated into consecutive control channel elements (CCEs), where a control channel element corresponds to 9 RE groups as defined in Sect. 6.2.4 of NPL2. The DCI transports downlink or uplink scheduling information, requests for aperiodic CQI reports, notifications of uplink power control commands, etc. as described in the Sect. 5.3.3 of 3GPP TS 36.212 v10.3.0, Multiplexing and channel coding for Evolved Universal Terrestrial Radio Access (E-UTRA) (Release 10) (referred to as “NPL3”). The CCEs of multiple UEs connected to same serving cell are multiplexed and then scrambled by using a scrambling sequence initialized by a value c init at the start of each subframe, which is a function of physical-layer cell identity (ID) of the serving cell as defined in the following equation in the Sect. 6.8.2 of NPL2 for interference randomization. In the following, the initialization value of scrambling sequence generation is called as the scrambling initialization value cinit for the sake of convenience.
c init =└n s /2┘2 9 +N ID ServCell {Math. 1}
where n s is the slot number within a radio frame.
The scrambled bit sequence is QPSK (Quadrature Phase Shift Keying)-modulated and mapped to the resource elements of PDCCH. The serving cell reserves a radio resource region for PDCCH of its UEs, i.e., whole bandwidth of first several OFDM symbols (max. 4 OFDM symbols) in a subframe. With the assistance of blind detection at UE side, only the location of the reserved radio resource region is required to be known by UE. The information of the location of the reserved radio resource is dynamically indicated by using L1/L2 signal through such as physical control format indicator channel (PCFICH), defined in the Sect. 6.7 of NPL2.
The present PDCCH, demodulated by cell-specific reference signal (CRS), is sent only by the serving cell and always occupies the entire system bandwidth of the first several OFDM symbols. It is not flexible to tailor the transmission characteristics of PDCCH to an individual UE and also impossible to coordinate transmissions in the frequency domain. This makes PDCCH ill-suited for new deployment, where the notion of a cell is less clear and where flexibility in how to transmit is needed to handle unexpected interference situations. Due to unexpected interferences, PDCCH capacity becomes a bottleneck when applying carrier aggregation, downlink enhanced MIMO and CoMP, etc.
In order to eliminate such a bottleneck, enhanced PDCCH (ePDCCH) has been proposed by R1-113155, Nokia (referred to as “NPL4”) and R1-113356, Ericsson, ST-Ericsson (referred to as “NPL5”). As shown in FIG. 1 , the ePDCCH is sent over allocated resource blocks (RBs) in physical downlink data channel (PDSCH) area to increase the capacity and coverage of the control signal. The employment of UE-specific RS (DM-RS) in ePDCCH transmission makes the transmission properties transparent to the UE. In principle, the enhanced single-point MIMO as well as multi-point MIMO (i.e., CoMP) schemes for improving the throughput of data transmission becomes also available for the DL control signal transmission, as stated in NPL5. For the blind detection of ePDCCH at UE side, the location of the reserved radio resource region may be informed semi-statically (e.g., 120 ms, 240 ms, etc.) as the information element of E-PDCCH-Config by RRC signaling, similar to the way to inform the configuration of the relay PDCCH (R-PDCCH) as introduced in the Sect. 6.3.2 of 3GPP TS 36.331 v10.3.0, Radio resource control (RRC) and Protocol specification of Evolved Universal Terrestrial Radio Access (E-UTRA) (Release 10) (hereinafter referred to as “NPL6”).
For LTE-Advanced Rel. 11, CoMP has been agreed to be included as a tool to improve the coverage of high data rates, the cell-edge throughput, and also to increase system throughput as described in the Sect. 4 of 3GPP TR 36.819 v11.0.0, Coordinated multi-point operation for LTE physical layer aspects (Release 11) (hereinafter referred to as “NFL 7”). The CoMP schemes, joint transmission (JT), dynamic point selection (DPS), and coordinated scheduling/coordinated beamforming (CS/CB) are supposed to be supported as described in the Sect. 5.1.3 of NPL7. The CoMP cooperating set is defined in the Sect. 5.1.4 of NPL7 as a set of (geographically separated) points directly and/or indirectly participating in data transmission to a UE in time-frequency resource. In case of JT and DPS, UE's data, scrambled by a scrambling sequence with the serving cell's scrambling initialization value as defined in the Sect. 6.3.1 of NPL2, should be shared among more than one point in CoMP cooperating set; while, in case of CS/CB, data for a UE is only available at and transmitted from the one point (serving point) but user scheduling/beamforming decisions are made with coordinated among points corresponding to the CoMP cooperating set. It should be noted that the term “point” for coordinated multi-point transmission/reception can be used as a radio station, a transmission/reception unit, remote radio equipment (RRE) or distributed antenna of a base station, Node-B or eNB. Accordingly, hereinafter, a point, a radio station, a transmission/reception unit and a cell may be used synonymously.
According to the performance evaluation results in Sect. 7 of NPL7, JT/DPS CoMP achieves better performance than CB/CS to improve the cell-edge user throughput of downlink data transmission. For a cell-edge UE, which suffers from poor channel condition of serving point and strong interference from CoMP point, JT/DPS CoMP can also be applied to improve the capacity of its control signal in a similar way as that of data, by sharing not only data but also control signal, scrambled by a scrambling sequence with the serving cell's scrambling initialization value cinit among the selected transmission points (TPs).
A simple example of the above-described scheme is given in FIGS. 2A and 2B . Assuming that UE 1 and UE 2 have Cell 1 as serving cell and Cell 2 as CoMP cell as shown in FIG. 2A , ePDCCH can aggregate control information of the UE 1 and UE 2 using the same scrambling sequence for Cell 1 and Cell 2 as shown in FIG. 2B . As described in Section 6.8.2 of the NPL2, the scrambling sequence generation is initialized with the following initialization value c init determined by the ID of Cell 1 (serving cell).
c init =└n s /2┘2 9 +N ID Cell1 {Math. 2}
In the case of the UE 2 with a different serving cell, however, the aggregation of control signal with CoMP cannot be made because different scrambling initialization values and different radio resources are used for the control signals of the UE 1 and UE 2 , respectively. As shown in FIG. 3A , it is assumed that UE 1 and UE 2 are selected as CoMP UEs with multiple cooperating cells and the UE 1 has Cell 1 as serving cell and Cell 2 102 as CoMP cell; while, the UE 2 has Cell 2 as the serving cell and Cell 1 as the CoMP cell. For the employment of JT/DPS CoMP, the control signal of UE 1 , scrambled by using the Cell 2 's scrambling initialization value, is shared by Cell 2 . On the other hand, the control signal of UE 2 , scrambled by using the Cell 2 's scrambling initialization value, is shared by Cell 1 . Accordingly, the scrambling sequence generation is initialized with different initialization values c init1 and c init2 for Cell 1 and Cell 2 , respectively:
c init1 =└n s /2┘2 9 +N ID Cell1
c init2 =└n s /2┘2 9 +N ID Cell2 {Math. 3}
Besides their different scrambling initialization values, different radio resource regions are reserved at Cell 1 and Cell 2 for sending UE 1 's and UE 2 's control signals, respectively as shown in FIG. 3B . Within the previously reserved radio resource region, the occupied resource is dynamically allocated, resulting in remained resource.
In FIG. 3B , as an example, separate resources with max 3RBs for each one are reserved for each UE, but average 2RBs are used for each UE's control signal. As a consequence, an increasing number of CoMP UEs with different serving cells results in larger reserved radio resource regions in multiple cooperating cells.
An object of the present invention is to provide a method and system which can efficiently send control signals with improved capacity and coverage of a control signal for UEs with different serving cells.
SUMMARY
According to the present invention, a radio communication system includes: a plurality of cells having different scrambling sequences, respectively, wherein at least two cells communicate with at least two user terminals connected to different serving cells; and a controller which controls the plurality of cells and provides a single scrambling sequence to said at least two cells and said at least two user terminals for control signal transmission and reception.
According to the present invention, a method for controlling a plurality of cells having different scrambling sequences in a radio communication system, includes the steps of: setting at least two cells which communicate with at least two user terminals connected to different serving cells; and providing a single scrambling sequence to said at least two cells and said at least two user terminals for control signal transmission and reception.
According to the present invention, a control device for controlling a plurality of cells having different scrambling sequences in a radio communication system, includes: a setting section for setting at least two cells which communicate with at least two user terminals connected to different serving cells; and a communication controller for providing a single scrambling sequence to said at least two cells and said at least two user terminals for control signal transmission and reception.
Advantageous Effects of Invention
According to the present invention, the reserved radio resource region for control signals for UEs with different serving cells can be effectively reduced. In addition, the exchanging messages among cooperating cells for the control signal of UEs also become less for coordinating the distributed scheduling results of different cooperating cells.
For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic diagram illustrating an example of control signal configuration of PDCCH and enhanced PDCCH (ePDCCH).
FIG. 2A is a schematic diagram illustrating a radio communication system having two UEs with same serving cell.
FIG. 2B is a schematic diagram illustrating the control signal configuration for each UE in the radio communication system of FIG. 2A .
FIG. 3A is a schematic diagram illustrating a radio communication system having two UEs with different serving cells.
FIG. 3B is a schematic diagram illustrating the control signal configuration for each UE in the radio communication system of FIG. 3A .
FIG. 4A is a schematic diagram illustrating control signal configuration for a CoMP UE group for explaining an outline of the present invention.
FIG. 4B is a schematic diagram illustrating the function configuration of a control unit to implement the control signal configuration of FIG. 4A .
FIG. 5 is a diagram illustrating an example of a radio communication system according to a first illustrative embodiment.
FIG. 6 is a diagram illustrating detailed functional configurations of the controller, TxRx units and UEs in the radio communication system of FIG. 5 .
FIG. 7 is a sequence diagram illustrating an example of operations of radio communication system of FIG. 6 .
FIG. 8A is a schematic diagram illustrating a first example of the radio communication system employing JT CoMP to ePDCCH and PDSCH for UE 1 and UE 2 according to the first illustrative embodiment.
FIG. 8B is a schematic diagram illustrating the control signal configuration for each UE in the radio communication system of FIG. 8A .
FIG. 9A is a schematic diagram illustrating a second example of the radio communication system employing DPS CoMP to ePDCCH and PDSCH for UE 1 and UE 2 according to the first illustrative embodiment.
FIG. 9B is a schematic diagram illustrating the control signal configuration for each UE in the radio communication system of FIG. 9A .
FIG. 10A is a schematic diagram illustrating a third example of the radio communication system employing JT CoMP to PDCCH and PDSCH for UE 1 and UE 2 according to the first illustrative embodiment.
FIG. 10B is a schematic diagram illustrating the control signal configuration for each UE in the radio communication system of FIG. 10A .
FIG. 11A is a schematic diagram illustrating a fourth example of the radio communication system employing DPS CoMP to PDCCH and PDSCH for UE 1 and UE 2 according to the first illustrative embodiment.
FIG. 11B is a schematic diagram illustrating the control signal configuration for each UE in the radio communication system of FIG. 11A .
FIG. 12 is a diagram illustrating an example of a radio communication system according to a second illustrative embodiment.
FIG. 13 is a diagram illustrating detailed configurations of eNBs in the radio communication system of FIG. 12 .
FIG. 14 is a sequence diagram illustrating an example of operations of radio communication system of FIG. 13 .
DETAILED DESCRIPTION
First, the general outlines of the present invention will be described with reference to FIGS. 4A and 4B .
As shown in FIG. 4A , multiple UEs (UE 1 , . . . UEn) with the same CoMP cooperating set but different serving cells are aggregated as a CoMP UE group with a single scrambling initialization value which is shared among cooperating cells of the CoMP cooperating set. A reserved resource Rrsv is determined so as to accommodate a total amount of resources for control signals of the UE 1 -UEn in the CoMP UE group. The respective resources for control signals of the UE-UEn in the CoMP UE group are dynamically allocated within the reserved resource Rrsv and the control signals in the CoMP UE group are scrambled using the single scrambling initialization value.
Referring to FIG. 4B , it is assumed that a core control unit controls radio transmission and reception stations TxRx_ 1 , . . . TxRx_n (hereinafter, referred to as TxRx units) which in turn control UE 1 -UEn with different serving cells corresponding to the TxRx units, respectively. The core control unit performs: grouping the UE 1 -UEn with different serving cells but the same CoMP cooperating set into a CoMP UE group; selecting the scrambling initialization value for the CoMP UE group; and reserving the shared resource Rrsv as shown in FIG. 4A . Thereafter, the core control unit performs coordinated scheduling and informing control signal configuration to each TxRx unit. In this way, the information related to the scrambling initialization value and the reserved resource Rrsv is shared among the TxRx units and the UEs for transmitting and receiving control signals.
As an example, considering that UE 1 and UE 2 are connected to different serving cells (Cell 1 and Cell 2 ) but having the same CoMP cooperating set, UE 1 and UE 2 can be grouped as a CoMP UE group. A common scrambling initialization value is used for initializing the scrambling sequence of their control signal. In addition, the reserved resource region Rrsv for control signal transmission can be set to 5RBs at Cell 1 and Cell 2 , where each UE uses average 2RBs for sending DCI. In this case, the reserved resource region Rrsv is smaller than a total resource (6RBs) for separate control signal transmission of the UE 1 and UE 2 .
The illustrative embodiments will be explained by making references to the accompanied drawings. The illustrative embodiments used to describe the principles of the present invention are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged wireless network. In the present technical field related to radio communication systems, the terms “point”, “cell”, “radio station” and “transmission/reception (TxRx) unit” of a base station (Node-B or eNB) may have same meaning, so serving point and cooperating point can be interpreted as serving cell and cooperating cell, serving TxRx unit and cooperating TxRx unit, or serving radio station and cooperating radio station, respectively. Accordingly, in this disclosure, the term “cell” or “TxRx unit” is used appropriately.
1. First Illustrative Embodiment
According to the first illustrative embodiment, intra-eNB CoMP is applied to control signal transmission. Detailed configuration and operation will be described by referring to FIGS. 5-7 .
1.1) System Configuration
As shown in FIG. 5 , it is assumed that a network is composed of a controller 10 and TxRx units 21 and 22 (or Cell 1 and Cell 2 ), to which a radio communication system according to the first illustrative embodiment is applied. The controller 10 controls the TxRx units 21 and 22 (or Cell 1 and Cell 2 ) through backhaul links BL 1 and BL 2 , respectively. The UE 1 and UE 2 are communicating with the TxRx units 21 and 22 through radio channels under the control of the network. More detailed configuration of the radio communication system will be described below.
Referring to FIG. 6 , the controller 10 includes the function blocks of: CoMP cooperating set selection section 101 ; CoMP UE grouping section 102 ; scrambling initialization value selection section 103 ; resource reservation section 104 ; scheduler 105 ; backhaul link (BL) communication section 106 ; and a control section 107 . The TxRx units 21 and 22 have the same functional configuration as follows: BL communication section 211 , 221 ; control section 212 , 222 ; radio transmitter 213 , 223 ; and radio receiver 214 , 224 . The BL communication sections 211 and 221 are connected to the backhaul link (BL) communication section 106 through the backhaul links BL 1 and BL 2 , respectively, so that data and control signal transmission/reception can be controlled by the controller 10 . The UE 1 and UE 2 have the same functional configuration as follows: radio transmitter 311 , 321 ; radio receiver 312 , 322 ; DL signal detection section 313 , 323 ; channel state information (CSI) estimation section 314 , 324 ; and controller 315 , 325 . Each cell (TxRx unit 21 , 22 ) in CoMP cooperating set is communicating with the UE 1 and UE 2 , which are also referred to as CoMP UEs.
By using the above-mentioned function blocks, the CoMP cooperating set selection section 101 selects a CoMP cooperating set including more than one cell (here, TxRx units 21 and 22 ) for each UE (here, UE 1 , UE 2 ). Thereafter, the CoMP UE grouping section 102 groups the CoMP UEs with the same CoMP cooperating set as a CoMP UE group. For sending the control signal of such a CoMP UE group, the scrambling initialization value selection section 103 chooses a single scrambling initialization value and the resource reservation section 104 reserves the shared radio resource region Rrsv. Next, the scheduler 105 performs the joint scheduling of multiple cells belonging to the CoMP cooperating set, where the network dynamically selects the transmission point(s), TP(s), of TxRx unit(s), and on selected TP(s) allocates the RBs as well as REs within the reserved resource region Rrsv for each UE in the CoMP UE group. In case of precoding at selected TP(s), the precoding matrix index (PMI) as well as rank indicator (RI) for each UE needs to be decided for each selected TP. The detailed process is described as follows.
Referring to FIG. 7 , at first, when the TxRx units 21 and 22 have received an uplink signal from the UE 1 and UE 2 , respectively (operations 401 and 402 ), the control sections 212 and 222 transmits information indicating the received power of uplink sounding reference signal (SRS) or the UE feedback downlink reference signal received power (RSRP) to the controller 10 through the BL communication section 211 and 221 (operations 403 and 404 ). Based on the information indicating SRS power or the RSRP, the CoMP cooperating set selection section 101 selects the CoMP cooperating set for each UE (operation 405 ). For example, a cell, whose RSRP difference relative to that of the serving cell is within a threshold, will be regarded as a CoMP cell. The UE having more than one cooperating cell is regarded as a cooperating cell (CoMP cell). It is found that UE 1 and UE 2 are CoMP UEs, who have the same CoMP cooperating set consisting of Cell 1 and Cell 2 , although UE 1 's serving cell is Cell 1 and UE 2 's serving cell is Cell 2 .
The CoMP UE grouping section 102 groups UE 1 and UE 2 into one CoMP UE group (operation 406 ). For this CoMP UE group, the scrambling initialization value selection section 103 selects a single scrambling initialization value for the scrambling sequence of control signal, e.g., PDCCH or ePDCCH (operation 407 ). The scrambling initialization value can be determined by the ID of one CoMP cooperating cell, i.e., Cell 1 's ID or Cell 2 's ID, or a different ID for the sake of interference randomization. For example, the scrambling sequence is initialized as a common initialization value c init for Cell 1 -Celln as follows:
c init = ⌊ n s / 2 ⌋ 2 9 + N ID VIRTUAL _ { Math . 4 }
where N ID VIRTUAL is a specific virtual cell ID for the CoMP UE group.
c init =└n s /2┘2 9 +N ID ServCell +N offset {Math. 5}
where N offset is the ID offset for each UE belong to the CoMP UE group. N offset is adjusted to obtain same cinit for each UE in CoMP UE group.
The control section 107 sends the virtual cell ID or cell ID offset, parameter of scrambling initialization value cinit, to the TxRx units 21 and 22 (operations 408 and 409 ) for generating the CoMP UE group's control signal, and the TxRx units 21 and 22 further send it to the UE 1 and UE 2 as the information element of PDCCH-Config or E-PDCCH-Config by RRC signaling for detecting the control signal, respectively (operations 410 and 411 ).
Next, the resource reservation section 104 reserves the shared radio resource region Rrsv (see FIG. 4A ) at both Cell 1 and Cell 2 for applying JT/DPS CoMP to control signal transmission (operation 412 ). The control section 107 notifies the TxRx units 21 and 22 of the location of the shared radio resource region Rrsv (operations 413 and 414 )), which further send it to the UE 1 and UE 2 (operations 415 and 416 ).
According to the feedback CSI by UE, the scheduler 105 firstly carries out channel-dependent scheduling for data transmission and thereafter each UE's DCI including dynamic scheduling results can be aggregated into consecutive CCEs (operation 417 ). For each UE in the CoMP UE group, the control section 107 selects transmission points (TxRx units) and allocates RBs and REs within the reserved radio resource region Rrsv. In case of precoding, the PMI as well as RI for each selected TP of the CoMP UE are also decided, respectively. For control signal transmission, besides the virtual cell ID or cell ID offset for scrambling initialization value cinit, the control section 107 also informs each selected TxRx unit, through a corresponding backhaul link, of dynamic scheduling results which includes the aggregated CCE number, the positions of allocated RBs and REs as well as PMI and RI for precoding (operations 418 and 419 ).
The virtual cell ID or cell ID offset for generating the scrambling initialization value c init of the CoMP UE group may be indicated semi-statically, e.g., 120 ms, 240 ms, etc.; while, the dynamic scheduling results need to be updated more frequently, e.g., with a period of 5 ms, 10 ms, etc. Accordingly, each of the control sections 212 and 222 generates the control signal of the CoMP UE group by multiplexing the CCEs of the UE 1 's DCI and UE 2 's DCI at first and then scrambling the bit sequence by using the scrambling initialization value cinit with the informed virtual cell ID or cell ID offset (operations 420 and 421 ). After that, the transmitter 213 , 223 of a corresponding TxRx unit modulates the scrambled bit sequence and maps the modulated signal on the allocated REs within the allocated RBs to send the control signal of the CoMP UE group.
As described above, for control signal detection at UE side, the control section 107 informs each UE in the CoMP UE group of the virtual cell ID or cell ID offset for generating the scrambling initialization value cinit as well as the location of the reserved radio resource region Rrsv. The signal related to the virtual cell ID or cell ID offset of the scrambling initialization value cinit and the signal related to the location of reserved radio resource region Rrsv may be sent simultaneously or independently. For example, the information of the scrambling initialization value cinit together with the location of reserved radio resource region Rrsv may be included in the information elements of PDCCH-Config or E-PDCCH-Config by RRC signaling and semi-statically indicated through PDSCH of serving cell with a period of 120 ms, 240 ms, etc. At the UE side, the blind detection within the informed reserved region Rrsv is carried out to detect the control signal. In another way, the location of radio resource region Rrsv may be dynamically sent to the UE by using L1/L2 signal with a period of 5 ms, 10 ms, etc., independently from that of the scrambling initialization value cinit. For example, for PDCCH, the reserved region Rrsv is the first several OFDM symbols and the number of the OFDM symbols for PDCCH is dynamically informed to UE by using the L1/L2 signal through PCFICH, which includes the information of the length of Rrsv for PDCCH. For ePDCCH, the start position of ePDCCH can be semi-statically informed by using RRC signal and the length of Rrsv for ePDCCH can be dynamically informed to UE by using the L1/L2 signal through enhanced PCFICH at the beginning of ePDCCH, which carries the information of the length of the ePDCCH resource. Or, the dynamic signaling of the region Rrsv for ePDCCH is informed to UE through its serving cell's PDCCH. In this case, the UE firstly detects the PDCCH to obtain the location of the region Rrsv and then detects the ePDCCH within the region Rrsv. Thereafter, the blind detection may be avoided at the price of larger signaling overhead for the information in PDCCH. The detailed examples are given below.
With the knowledge of the virtual cell ID or cell ID offset for scrambling initialization value cinit and the reserved resource region Rrsv, the DL signal detection section 313 , 323 of each UE can detect the control signal, by demapping the received signal, demodulating the symbol sequence, and then descrambling the bit sequence (operations 422 and 423 ). Hereafter, the UE 1 's DCI and UE 2 's DCI are blindly detected in the informed reserved resource region Rrsv, respectively.
According to each UE's DCI associated with the downlink transmission, the CSI estimation section 314 , 324 can further detect its received downlink data in PDSCH as well as the downlink reference signal for CSI estimation. According to the UE's DCI associated with the uplink transmission, the control section 315 , 325 generates the uplink data and sends over physical uplink shared channel (PUSCH) from each UE's transmitter 311 , 321 . In addition, the control section 315 , 325 generates the feedback CSI together with other uplink control information and sends over physical uplink control channel (PUCCH).
1.2) First Example
A first example of the communication control method according to the first illustrative embodiment shows the case of ePDCCH with JT CoMP, which will be described by referring to FIGS. 8A and 8B .
As shown in FIG. 8A , JT CoMP is applied to send ePDCCH of CoMP UE group from multiple selected TPs (TxRx units 21 and 22 ). Here, JT CoMP is also applied to data transmission over PDSCH for UE 1 and UE 2 . The TxRx units 21 and 22 (Cell 1 and Cell 2 ) are the selected TPs, simultaneously transmitting both data and control signal to UE 1 and UE 2 . For ePDCCH, a common scrambling initialization value cinit is needed and a common radio resource region Rrsv is reserved for UE 1 and UE 2 .
As shown in FIG. 8B , over reserved resource region Rrsv, same RBs as well as REs are allocated for each UE's DCI at both Cell 1 and Cell 2 (TxRx units 21 and 22 ). In case of precoding of joint transmission, the PMI and RI at Cell 1 and Cell 2 need to be decided based on the UE feedback CSI. For ePDCCH generation, the information of the common scrambling initialization value cinit and the above dynamic scheduling results is indicated to each selected TxRx unit over a corresponding backhaul link BL. For ePDCCH detection, only the information related to the common scrambling initialization value cinit (i.e., virtual cell ID or cell ID offset for the CoMP UE group) together with the location of reserved resource region Rrsv is needed for the sake of blind detection at the UE side.
1.3) Second Example
A second example of the communication control method according to the first illustrative embodiment shows the case of ePDCCH with DPS, which will be described by referring to FIGS. 9A and 9B .
As shown in FIG. 9A , DPS CoMP is applied to send ePDCCH of the CoMP UE group from one dynamically selected TP (TxRx unit). The process is similar to that of ePDCCH with JT CoMP given in FIGS. 8A and 8B , except that only one TP(TxRx unit) is dynamically selected for sending PDSCH and ePDCCH. Although the common radio resource region Rrsv is reserved at both Cell 1 and Cell 2 (TxRx units 21 and 22 ), the control section 107 only allocates RBs and REs within the reserved radio resource region Rrsv at each UE's selected TP (TxRx unit).
As shown in FIG. 9B , 1the UE 1 's data and DCI is sent from the TxRx unit 21 (Cell 1 ); while the UE 2 's data and DCI is sent from the TxRx unit 22 (Cell 2 ) at a current subframe. In another subframe, it is possible that the UE 1 's data and DCI is sent from the TxRx unit 22 (Cell 2 ) but the UE 2 's data and DCI is sent from TxRx unit 21 (Cell 1 ). The selected TP (TxRx unit) may be dynamically updated with a period of 5 ms, 10 ms, etc. For ePDCCH generation, the information related to the common scrambling initialization value cinit and the above dynamic scheduling results are indicated to the UE's selected TP (TxRx unit) over a corresponding backhaul link BL. For ePDCCH detection at the UE side, only the information of the common scrambling initialization value cinit and the location of reserved resource region Rrsv are needed.
As illustrated in above example of ePDCCH with JT/DPS CoMP, only the location of reserved resource region Rrsv needs to be informed to UE semi-statically for blind detection of control signal. It is also possible to semi-statically inform the start position of ePDCCH but dynamically send the length of reserved resource region Rrsv, such as the number of RBs for Rrsv, in a L1/L2 signal through such as enhanced PCFICH (ePCFICH), which carries information about the number of RBs, used for transmission of ePDCCH in a subframe. To avoid blind detection, the aggregation level (i.e., number of aggregated CCEs) and the position of the allocated RBs and/or REs may be informed directly by using a L1/L2 signal over PDCCH, at the price of higher signaling overhead.
1.4) Third Example
A third example of the communication control method according to the first illustrative embodiment shows the case of PDCCH with JT CoMP, which will be described by referring to FIGS. 10A and 10B .
As shown in FIG. 10B , JT CoMP is applied to send PDCCH of the CoMP UE group from multiple selected TPs (TxRx units 21 and 22 ). The process is similar to that of ePDCCH with JT CoMP given in FIGS. 8A and 8B , except that the allocated resources are restricted to the first several OFDM symbols in case of PDCCH. Since the CRS and PCFICH with cell-specific shift occupy the REs also in the first OFDM symbols, the UE 1 's DCI and UE 2 's DCI may be mapped to the REs without conflict with the CRS and PCFICH of Cell 1 and Cell 2 . For PDCCH generation, the virtual cell ID or cell ID offset for common scrambling initialization value cinit, the OFDM index as well as the aggregation level and the position of allocated RBs/REs for each UE needs to be known at each selected TP (TxRx unit). For PDCCH detection, the virtual cell ID or cell ID offset for common scrambling initialization value cinit is informed semi-statically to each UE of PDCCH-Config or E-PDCCH-Config by RRC signaling; while, the location of the reserved resource region Rrsv is indicated dynamically through PCFICH, which carries information about the number of OFDM symbols, used for transmission of PDCCH in a subframe. As shown in FIG. 10B , the data and DCI of UE 1 and UE 2 are simultaneously transmitted by Cell 1 and Cell 2 (TxRx units 21 and 22 ) over allocated RBs and REs in the shared reserved OFDM symbols. The UE 1 and UE 2 can detect its own DCI by blind detection within the informed region Rrsv of PDCCH.
1.5) Fourth Example
A fourth example of the communication control method according to the first illustrative embodiment shows the case of PDCCH with DPS, which will be described by referring to FIGS. 11A and 11B .
As shown in FIG. 11A , DPS CoMP is applied to send PDCCH of the CoMP UE group from a dynamically selected TP (TxRx unit). The process is similar to that of PDCCH with JT CoMP given in FIGS. 10A and 10B , except that only one TP (TxRx unit) is dynamically selected in a subframe for sending PDSCH and PDCCH. Although the common radio resource region Rrsv is reserved at both Cell 1 and Cell 2 (TxRx units 21 and 22 ), the control section 107 only allocates the RBs and REs within the reserved radio resource region Rrsv at each UE's selected TP (TxRx unit).
As shown in FIG. 11B , the UE 1 's data and DCI is sent from Cell 1 (TxRx unit 21 ); while the UE 2 's data and DCI is sent from Cell 2 (TxRx unit 22 ) at current subframe. In another subframe, it is possible that the UE 1 's data and DCI is sent from Cell 2 (TxRx unit 22 ) but the UE 2 's data and DCI is sent from Cell 1 (TxRx unit 21 ). The selected TP (TxRx unit) may be dynamically updated with a period of 5 ms, 10 ms, etc. For PDCCH generation, the information related to the common scrambling initialization value cinit and the above dynamic scheduling results is indicated to the UE's selected TP (TxRx unit). For PDCCH detection, the virtual cell ID or cell ID offset for common scrambling initialization value cinit for the CoMP UE group is informed semi-statically to each UE of PDCCH-Config or E-PDCCH-Config by RRC signalling; while, the location of the reserved resource region Rrsv, i.e. the number of OFDM symbols for PDCCH, is indicated dynamically as a L1/L2 signal through PCFICH.
1.6) Other Examples
In the above-described examples as shown in FIGS. 8-11 , the same CoMP scheme by using same selected TP(s) is used to send the downlink data over PDSCH and the downlink control signal over ePDCCH or PDCCH. However, the CoMP scheme as well as TP(s) can be independently decided for control signal and data transmission. For example, JT is used for data transmission but DPS is used for control signal transmission, considering the limited radio resources.
2. Second Illustrative Embodiment
According to the second illustrative embodiment, inter-eNB CoMP is applied to control signal transmission. Detailed configuration and operation will be described by referring to FIGS. 12-14 .
As shown in FIG. 12 , eNB 1 and eNB 2 are connected by X2 backhaul link. Each eNB includes the same functions as those of the controller 10 as shown in FIG. 6 . More specifically, as shown in FIG. 13 , Each eNB is provided with BL communication section ( 211 , 221 ), radio transmitter ( 213 , 223 ); radio receiver ( 214 , 224 ); and control section ( 210 , 220 ). The control section ( 210 , 220 ) has not only the functions for eNB operations as described before but also the functions for inter-eNB CoMP applied to control signal transmission. The BL communication sections 211 and 221 are connected to each other through the X2 backhaul link, allowing the inter-eNB CoMP for control signal transmission. Other function blocks similar to those described with reference to FIG. 6 are denoted by the same reference numerals and their detailed descriptions are omitted.
By using the above-mentioned function blocks, the control section 210 , 220 can find the CoMP UEs connected to eNB 1 and eNB 2 , respectively. The UE 1 has serving eNB 1 and cooperating eNB 2 ; while the UE 2 has serving eNB 2 and cooperating eNB 1 . By exchanging information over the X2 backhaul link, the CoMP UEs with the same CoMP cooperating set are grouped at each eNB. For control signal transmission of the UE 1 and UE 2 , the common scrambling initialization value cinit is chosen and the shared radio resource region Rrsv is reserved. More specifically, the operations of the control sections 210 and 220 will be described by reference to FIG. 14 .
Referring to FIG. 14 , at first, when the eNB 1 and eNB 2 have received an uplink signal from the UE 1 and UE 2 , respectively (operations 501 and 502 ), the control sections 210 and 220 use information of the received power of uplink sounding reference signal (SRS) or the UE feedback downlink reference signal received power (RSRP) to select the CoMP cooperating set for each UE (operations 503 . 1 , 503 . 2 ). After exchanging the information related to each UE's CoMP cooperating set through X2 backhaul between sections 211 and 221 , the control sections 210 and 220 group UE 1 and UE 2 into one CoMP UE group (operations 504 . 1 , 504 . 2 ). For this CoMP UE group, the control sections 210 and 220 select a virtual cell ID or cell ID offset for determining the same scrambling initialization value cinit for ePDCCH of each UE in the CoMP UE group (operations 505 . 1 , 505 . 2 ). The virtual cell ID or cell ID offset can be the same as the ID of one CoMP cooperating cell, i.e., Cell 1 's ID or Cell 2 's ID, or a different ID for the sake of interference randomization. The control sections 210 and 220 send the virtual cell ID or cell ID offset to the UE 1 and the UE 2 , respectively (operations 506 and 507 ). The scrambling sequence is initialized by a common initialization value c init for Cell 1 and Cell 2 as described before.
Next, by exchanging the information over X2 backhaul, the control sections 210 and 220 reserve the shared radio resource region Rrsv (see FIG. 4A ) at both Cell 1 and Cell 2 for control signal transmission (operations 508 . 1 , 508 . 2 ). The control sections 210 and 220 notify the UE 1 and UE 2 of the location of the shared radio resource region Rrsv (operations 509 and 510 ).
Next, the control sections 210 and 220 perform the distributed scheduling at eNB 1 and eNB 2 , respectively (operations 511 . 1 , 511 . 2 ). Each control section of the eNB 1 and eNB 2 dynamically assigns the resources for each UE connected to the corresponding eNB. In case of precoding, the PMI as well as RI for each UE needs to be decided. By coordinating the results of distributed scheduling through the X2 backhaul link, the control sections 210 and 220 corporate each other for the data transmission with JT/DPS CoMP. After that, each UE's DCI including the dynamic scheduling results can be aggregated into consecutive CCEs.
For the UE in the CoMP UE group, each eNB allocates the RBs and REs within the reserved radio resource region Rrsv. By exchanging the information over the X2 backhaul link, the coordination among cooperating eNBs is needed for control signal transmission with JT/DPS CoMP. In case of JT CoMP, the same RBs as well as REs are allocated at eNB 1 and eNB 2 for UE 1 and UE 2 , respectively. In case of DPS, the RBs and REs at one selected eNB is allocated to achieve largest data rate. For coordinating the distributed scheduling results of different cooperating cells, the exchanging messages for the aggregated control signal of a CoMP UE group is relatively smaller than that of separate control signal for different CoMP UEs.
Accordingly, each of the control sections 210 and 220 generates the control signal of the CoMP UE group by multiplexing the CCEs of the UE 1 's DCI and UE 2 's DCI first and then scrambling the bit sequence by using the informed virtual cell ID or cell ID offset for generating same scrambling initialization value cinit for the CoMP UE group (operations 512 and 513 ).
With the knowledge of the virtual cell ID or cell ID offset for scrambling initialization value cinit and the reserved resource region Rrsv, each UE can detect the control signal, by demapping the received signal, demodulating the symbol sequence, and then descrambling the bit sequence (operations 514 and 515 ). Hereafter, the UE 1 's DCI and UE 2 's DCI are blindly detected in the informed reserved resource region Rrsv, respectively. The detailed process of the employment of JT/DPS CoMP on ePDCCH and PDCCH is similar to that of the first to fourth examples, which is not redundantly described here.
3. Additional Statements
The present invention can be applied to a mobile communications system employing coordinated transmission among multiple points to send control signal to multiple UEs.
The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The above-described illustrative embodiment and examples are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Part or all of the above-described illustrative embodiments can also be described as, but are not limited to, the following additional statements.
REFERENCE SIGNS LIST
10 controller
21 , 22 transmission/reception (TxRx) unit
UE 1 , UE 2 user equipment (user terminal)
101 CoMP cooperating set selection section
102 CoMP UE grouping section
103 scrambling initialization value selection section
104 resource reservation section
105 scheduler
106 backhaul link (BL) communication section
107 control section
210 , 220 control section
211 , 221 BL communication section
212 , 222 control section
213 , 223 transmitter
214 , 224 receiver
311 , 321 transmitter
312 , 322 receiver
313 , 323 DL signal detection section
314 , 324 CSI estimation section | A radio communication system includes: a plurality of cells having different scrambling sequences, respectively, wherein at least two cells communicate with at least two user terminals connected to different serving cells; and a controller which controls the plurality of cells and provides a single scrambling sequence to said at least two cells and said at least two user terminals for control signal transmission and reception. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to novel triarylmethyl free radicals and their use as image enhancing agents in magnetic resonance imaging (MRI), in particular to their use in electron spin resonance enhanced magnetic resonance imaging (OMRI) of a sample (for example a human or animal body) for determining the oxygen concentration of said sample.
MRI is a diagnostic technique that has become particularly attractive to physicians as it is non-invasive and does not involve exposing the patient under study to potentially harmful radiation (eg. X-rays). The technique, however, suffers from inter alia the problem of achieving effective contrast in the magnetic resonance (MR) images between tissue types having the same or closely similar imaging parameters.
Electron spin resonance enhanced MRI, referred to herein as OMRI(Overhauser MRI) but also referred to in earlier publications as ESREMRI or PEDRI, is a particular form of MRI in which enhancement of the magnetic resonance signals from which the images are generated is achieved by virtue of the dynamic nuclear polarization (the Overhauser effect) that occurs on VHF stimulation of an esr transition in a paramagnetic material, generally a persistent free radical, in the subject under study. Magnetic resonance signal enhancement may be by a factor of a hundred or more thus allowing OMRI images to be generated rapidly and with relatively low primary magnetic fields.
OMRI techniques have been described by several authors, notably Leunbach, Lurie, Ettinger, Grucker, Ehnholm and Sepponen, for example in EP-A-296833, EP-A-361551, WO-A-90/13047, J. Mag. Reson. 76:366-370(1988), EP-A-302742, SMRM 9:619(1990), SMRM 6:24(1987), SMRM 7:1094(1988), SMRM 8:329(1989), U.S. Pat. No. 4,719,425, SMRM 8:816(1989), Mag. Reson. Med. 14:140-147(1990), SMRM 9:617(1990), SMRM 9:612(1990), SMRM 9:121(1990), GB-A-2227095, DE-A-4042212 and GP-A-2220269.
In the basic OMRI technique, the imaging sequence involves initially irradiating a subject placed in a uniform magnetic field (the primary field B 0 ) with radiation, usually VHF radiation, of a frequency selected to excite a narrow linewidth esr transition in a paramagnetic enhancement agent (hereinafter "an OMRI contrast agent") which is in or has been administered to the subject. Dynamic nuclear polarization results in an increase in the population difference between the excited and ground nuclear spin states of the imaging nuclei, i.e. those nuclei, generally protons, which are responsible for the magnetic resonance signals. Since MR signal intensity is proportional to this population difference, the subsequent stages of each imaging sequence, performed essentially as in conventional MRI techniques, result in larger amplitude MR signals being detected and more effective contrast.
A number of oxygen free radicals that is to say radicals where the unpaired electron or electrons are associated with the oxygen atom have been proposed as OMRI contrast agents including for example nitroxide stable free radicals, chloranil semiquinone radical and Fremy's salt (U.S. Pat. No. 4,984,573) and deuterated stable free radicals, in particular deuterated nitroxide stable free radicals (WO-A-90/00904).
In WO-A-91/12024, Nycomed Innovation AB proposed persistant carbon free radicals, i.e. radicals (e.g. triarylmethyl radicals) in which the unpaired electron(s) are primarily associated with carbon atoms, for use as OMRI contrast agents.
In WO-A-96/39367, Nycomed Imaging AS proposed various sulphur-based triarylmethyl radicals for use as OMRI contrast agents.
In any OMRI experiment under ambient conditions, paramagnetic oxygen will have a finite effect on the spin system present. Generally speaking, this may be dismissed as a secondary effect when compared to the primary interaction of the radical electron spin and the nuclear spin system. Nonetheless, it has been proposed that this effect may be used to determine oxygen concentration within a sample. Research has concentrated particularly on the use of nitroxide spin labels; radicals which suffer the inherent disadvantage of having broad linewidth esr resonances and therefore low sensitivity to the effects of oxygen. Thus, to date, the effect of oxygen has been recognised only in a qualitative sense and any attempt to attach a quantitative significance to the oxygen effect has failed. Moreover, in general, non-invasive techniques for oxygen determination have been slow to develop and typically are not suited to the study of tissues lying deep beneath the surface of a sample.
For example, Grucker et al (MRM, 34:219-225(1995)) reported a method for calculating oxygen concentration by measuring the Overhauser effect attributable to a nitroxide radical and relating the non-linear effect of oxygen on the Overhauser Factor to its concentration. This involved taking two images, one on-resonance and one off-resonance, and using a first order approximation to arrive at the oxygen concentration. However, Grucker observed that the correlation between actual and calculated oxygen concentration was poor and therefore that the method was inherently inaccurate. This was attributed to the large number of parameters involved in the calculation.
Ehnholm (U.S. Pat. No. 5,289,125) proposed an OMRI technique in which signals from a paramagnetic material were detected under at least two different sets of operating parameters whereby to generate images of various physical, chemical or biological parameters. While oxygen tension was one of several such parameters, Ehnholm did not demonstrate the use of the technique to quantitate dissolved oxygen.
SUMMARY OF THE INVENTION
It has now been found that certain novel sulphur based triarylmethyl radicals have advantageous properties for example an improved metabolism pattern which makes them particularly suitable for use as OMRI contrast agents.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a typical OMRI imaging sequence used in the method of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Viewed from one aspect the present invention provides a radical compound of formula I ##STR1## (wherein: each X which may be the same or different represents an oxygen or sulphur atom or a group CO or S(O) m (where m is 1 to 3);
each R 1 which may be the same or different represents a hydrogen atom or group of formula --M, --XM, --X--Ar 2 or --Ar 2 ;
M represents a water solubilising group;
Ar 2 represents a 5-10 membered aromatic ring optionally substituted by a water solubilising group M;
each R 7 which may be the same or different represents a hydrogen atom, or a hydrocarbon group such as an alkyl, hydroxyalkyl, alkoxyalkyl, alkoxycarbonyl, or carbamoyl group, or a water solubilising group M or two groups R 7 together with the atom to which they are bound represent a carbonyl group or a 5 to 8 membered cycloalkylidene, mono- or di-oxacycloalkylidene, mono- or di-azacycloalkylidene or mono- or di-thiacycloalkylidene group optionally with the ring attachment carbon replaced by a silicon atom (preferably however in any spiro structure the ring linking atom will be bonded to no more than three heteroatoms) and R 7 where it is other than hydrogen, is optionally substituted by a hydroxyl group, an optionally alkoxylated, optionally hydroxylated acyloxy or alkyl group or a water solubilising group M;
n denotes 1, 2 or 3; and
each group Y which may be the same or different denotes any of the groups defined for R 7 hereinbefore with the proviso that at least one group Y is a hydroxylated C 2-6 -alkyl group, preferably a CH 2 CH 2 OH group) or a deuterated analog, precursor or salt thereof.
This definition covers radical precursors which may conveniently undergo a radical generation step shortly before administration or even in situ to produce the desired free radical. Radical precursors and radical generation steps are well-known to those skilled in the art.
Preferred radical compounds according to the invention include those of formula I wherein n is at least two and more preferably is three. Especially preferably, the group Y is in each case a hydroxylated C 2-6 -alkyl group, more especially preferably a hydroxylated C 2-4 -alkyl group, most especially a CH 2 CH 2 OH group.
In the radical compounds according to the invention, the solubilising groups M may be any of the solubilising groups conventionally used in diagnostic and pharmaceutical products. Particularly preferred solubilizing groups M include optionally hydroxylated, optionally alkoxylated alkyl or oxo-alkyl groups and groups of formulae R 5 , COOR 5 , OCOR 5 , CHO, CN, CH 2 S(O)R 5 , CONR 5 2 , NR 5 COR 5 , NR 5 2 , SO 2 NR 5 2 , OR 5 , PO 3 2- , SOR 5 , SO 2 R 5 , SO 3 M 1 , COOM 1 (where R 5 represents a hydrogen atom or an optionally hydroxylated, optionally aminated, optionally alkoxylated, optionally carboxylated alkyl, oxo-alkyl, alkenyl or alkaryl group and M 1 is one equivalent of a physiologically tolerable cation, for example an alkali or alkaline earth metal cation, an ammonium ion or an organic amine cation, for example a meglumine ion), --(O(CH 2 ) n ) m OR 5 (where n is an integer having a value of from 1 to 3 and m is an integer having a value of from 1 to 5), --CX(CHR 5 ) n X or CH 2 R 8 (where R 8 is a hydrophilic R 5 group) or SR 10 or SO 2 R 10 where R 10 is a group R 5 or an alkyl group optionally substituted by one or more, especially two or three groups COOR 5 , OCOR 5 , CHO, CN, CONR 5 2 , NR 5 COR 5 , NR 5 2 , SO 2 NR 5 2 , OR 5 , PO 3 2- , SOR 5 , SO 2 R 5 , SO 3 M 1 , COOM 1 , or --(O(CH 2 ) n ) m OR 5 .
Especially preferred as solubilizing groups M are groups of formula C(H) 3-n ,(CH 2 OH) n , R 9 , COR 9 , SR 9 , SOR 9 , SO 2 R 9 , CON(R 9 ) 2 , NR 9 2 , NHR 9 and CONHR 9 [where R 9 may represent a hydroxylated alkyl group such as a group ##STR2## (although any R 9 group attached to a sulphur, nitrogen or oxygen atom is preferably not hydroxylated at the a carbon)] and groups of formula SO 2 R 12 or SR 12 where R 12 is a group CH 2 COOR 3 , CH(COOR 13 ) 2 , CH 2 CONHR 9 , CH 2 CONR 9 2 , CR 5 (COOR 13 ) 2 , CH(CN)CO 2 R 13 , (CH 2 ) n SO 3 - M 1 , (CH 2 ) n COR 13 , CH(COR 9 )CH 2 COR 9 and CH(R 5 )COR 9 where n, M 1 and R 5 are as hereinbefore defined and R 13 is a hydrogen atom, an alkyl group or a group M 1 or R 9 .
In the radical compounds according to the invention, unless otherwise stated, any alkyl or alkenyl moiety preferably contains up to 6, especially preferably up to 4, carbon atoms.
In the radical compounds according to the invention, X is preferably selected from oxygen or sulphur atoms or SO 2 groups. Preferably two and especially preferably all four X groups are identical, especially preferably they are all sulphur atoms.
In the radical compounds according to the invention preferred identities for the group R 1 may be selected from the group consisting of --H, --SCH 2 COO - Na + , --SO 2 R 2 , --SR 2 , --SCH 2 COOCH 2 CH 3 , --SO 2 C(R 2 ) 2 CH 2 CHOHCH 2 OH, --SO 2 NR 2 2 , --SO 2 CH 2 CON (R 2 ) 2 , --C--(CH 2 CH 2 OH) 3 , --SO 2 --C(H) (COOCH 2 CH 3 ) 2 , --CH 2 CON(CH 2 CH 2 OH) 2 , --COOH, --CO 2 Me, --CO 2 Et, --CO 2 M 1 --SO 2 --C-- (CH 2 CH 2 OH) 2
COOCH 2 CH 3 ,
--SO 2 C-- (CH 2 CH 2 OH) 2
CH 2 OH,
(where M 1 is as hereinbefore defined and R 2 is H or optionally hydroxylated alkyl eg. CH 2 CH 2 OH, CH 2 CHOHCH 2 OH, CH 3 , CH 2 CH 3 , CH 2 (CHOH) 4 CH 2 OH) or deuterated analogues thereof.
The most preferred compound according to the invention is ##STR3##
Compounds according to the invention have been found to have an improved metabolism pattern, namely a half-life which is typically greater than 30 minutes when a dose of 0.05 mmol/kg is injected into a rat (where the half-life is defined as the time from injection until the radical concentration in the blood equates with the metabolite concentration).
Further aspects of the invention provide the use of a radical compound according to the invention for the manufacture of a contrast medium for use in OMRI and a method of magnetic resonance investigation of a sample, said method comprising introducing into said sample a radical compound according to the invention, exposing said sample to a first radiation of a frequency selected to excite electron spin transitions in said radical, exposing said sample to a second radiation of a frequency selected to excite nuclear spin transitions in selected nuclei (eg. protons) in said sample, detecting free induction decay signals from said sample, and, optionally, generating an image or dynamic flow data from said detected signals.
Viewed from a still further aspect, the invention provides a magnetic resonance imaging contrast medium composition comprising a radical compound according to the invention together with at least one pharmacologically acceptable carrier or excipient.
For in vivo imaging, the radical compound should preferably be a physiologically tolerable radical, or one presented in a physiologically tolerable, e.g. encapsulated, form.
For the method according to the invention the preferred radicals are those which have relatively few transitions, e.g. less than 15, preferably less than 10, in their ESR spectra and radicals having narrow linewidth ESR transitions, e.g. up to 500 mG, preferably less than 150 mG, especially less than 60 mG and particularly less than 25 mG, are especially preferred (The linewidths referred to are conveniently the intrinsic linewidths (full width at half maximum in the absorption spectrum) under ambient conditions).
Whilst low numbers of ESR transition lines are generally preferred to obtain more effective coupling of the ESR and NMR transitions, good coupling (and therefore enhancement of the MR signal) may also be achieved with radicals showing a large number of ESR transitions.
Where the radicals have a multiplicity of ESR transitions, the hyperfine splitting constant is preferably very small. In this connection radicals having as few as possible non-zero spin nuclei, positioned as far away as possible from the paramagnetic centre are thus especially preferred.
The radical compounds according to the invention may be coupled to further molecules for example to lipophilic moieties such as long chain fatty acids or to macromolecules, such as polymers, proteins, polysaccharides (e.g. dextrana), polypeptides and polyethyleneimines. The macromolecule may be a tissue-specific biomolecule such as an antibody or a backbone polymer such as polylysine capable of carrying a number of independent radical groups which may itself be attached to a further macromolecule. Coupling to lipophilic molecules or substitution of the radical with lipophilic groups is particularly useful since it may enhance the relaxivity of the radicals in certain systems such as blood. Such lipophilic and macromolecular derivatives of the radical compound of formula I and salts thereof form a further aspect of the present invention.
The linkage of a compound according to the invention to the further molecule may be effected by any of the conventional methods such as the carbodiimide method, the mixed anhydride procedure of Krejcarek et al. (see Biochemical and Biophysical Research Communications 77: 581 (1977)), the cyclic anhydride method of Hnatowich et al. (see Science 220: 613 (1983) and elsewhere), the backbone conjugation techniques of Meares et al. (see Anal. Biochem. 142: 68 (1984) and elsewhere) and Schering (see EP-A-331616 (Deutsch/Schering) for example) and by the use of linker molecules as described for in U.S. Pat. No. 5,208,324 (Klaveness/Nycomed).
In view of their beneficial properties, one further aspect of the present invention is the use of the radical compounds of the invention as conventional OMRI contrast agents, as ESR contrast agents or as ESR spin labels in ESR imaging or in magnetometry.
The radical compounds according to the invention have been found to be useful in providing a non-invasive method based on OMRI for determining the oxygen concentration of a sample (hereinafter the OXI method) which involves manipulation of the Overhauser effect attributable to the radical compounds of the invention. More specifically, the method is based on observing and manipulating the varying enhancement of a proton signal due to the changed saturation characteristics of the radical in the presence of oxygen.
Viewed from a yet further aspect the present invention provides a method of determining oxygen concentration in a sample, for example a human or non-human, preferably mammalian, subject, said method comprising the following steps:
introducing into said sample an effective amount of a physiologically tolerable radical compound according to the invention, preferably a radical having an esr transition with a linewidth (measured in water at 37° C.) of less than 400 mG, more preferably less than 150 mG;
irradiating said sample with radiation of an amplitude (i.e. power) and frequency selected to stimulate an electron spin resonance transition of said radical;
detecting electron spin resonance enhanced magnetic resonance signals from said sample under at least first, second and third conditions, whereby under said first and second conditions said radiation is of a first frequency, under said third conditions said radiation is of a second frequency different from said first frequency, under said first, second and third conditions said radiation is of a first, second and third amplitude, said first and second amplitudes at least being different from each other; and
manipulating said detected signals whereby to determine oxygen concentration in said sample.
In a preferred embodiment, the OXI method comprises:
(a) introducing a radical compound according to the invention, e.g. parenterally, for example by injection into body tissue or into the vasculature;
(b) generating a first OMRI image of said sample at VHF power P A , irradiation period T VHF1 and on-resonance (ΔH=o) (i.e. where the frequency of the radiation is selected to be the resonance frequency of the esr transition);
(c) generating a second OMRI image of said sample at a second VHF power P B , irradiation time T VHF1 and on-resonance (ΔH=O);
(d) generating a third OMRI image of said sample at VHF power P C (eg equal to P A or P B ), irradiation time T VHF1 and off-resonance (ΔH≠O, for example 100-200 mG);
(e) manipulating the images obtained in steps (b) to (d) and calibrating using parameters determined ex vivo to provide an oxygen image of said sample.
In an especially preferred embodiment, a fourth and fifth OMRI image are additionally generated in the imaging sequence. The conditions for the fourth image are identical to the first image but the VHF irradiation time T VHF2 is different (for example twice as long, i.e. T VHF2 =2T VHF1 ) and the fifth image is obtained without VHF irradiation, eg. is a native image of intensity I 0 , generated by conventional MRI with a repetition time T R =T VHF .
In a further embodiment, a native image (i.e. one obtained by conventional MRI) of the sample (e.g. body) may be generated to provide structural (e.g. anatomical) information upon which the oxygen image may be superimposed. In this way, precise location of, for example, an oxygen deficient tumour will be possible.
Accurate measurement of the level of oxygen in bodily tissues is an invaluable aid to the clinician and the OXI method has a variety of end uses. For example, knowledge of the concentration of oxygen dissolved in blood can be used (through known rate constants) to calculate the concentration of oxygen associated with haemoglobin. This is a useful parameter which is presently measured either by undesirable invasive techniques or using the BOLD MR imaging technique which involves high field imaging to determine the effect of oxygen on paramagnetic iron but which has the disadvantage that to determine blood oxygen concentration the volume of blood in which the measurement was made needs to be known.
Other uses of the OXI method will be readily apparent to the skilled person and include oxygen imaging (e.g. mapping) of, for example, the heart and arteries and of malignant tumours, for example in the brain, breast, lung, lymphoid tissues and superficial areas of the liver. In the case of oxygen imaging of tumours, success in treatment of malignant tumours by radiotherapy may be reflected in the level of oxygen in the tissue (typically an oxygen concentration of less than 0.01 mM will indicate that the tissue is necrotic and thus that treatment is likely to be ineffective).
It will also be apparent that the OXI method will be useful in cardiology, surgery and intensive care where levels of oxygen and even perfusion can be non-invasively assessed in almost any tissue.
The manipulation of the detected MR signals in the OXI method will generally be to generate an image data set (i.e. a data set from which an image may be generated) indicative of radical concentration and one or more image data sets indicative of radical electron relaxation times (generally T 1e , T 2e or T 1e- T 2e ) and manipulation of these data sets and calibration with ex vivo calibration data to yield an image data set indicative of oxygen concentration. This oxygen concentration image data set can be transformed into an oxygen concentration image or can be subject to an upper or lower limit filter to identify regions of high or low oxygen concentration, which can again if desired be displayed as an image.
Broadly speaking, the Overhauser enhancement of the proton MR signal is dependent on the relaxation times T 1e and T 2e of the esr transition of the radical used in the OXI method. These relaxation times themselves are dependent on the concentrations of the radical and dissolved oxygen in the body fluid as well as on the temperature and chemical nature of the body fluid. However while the Overhauser enhancement can easily be used to determine the oxygen concentration for an isolated small volume sample of known radical concentration ex vivo, the determination of oxygen concentration in vivo is complicated since the Overhauser enhancement is also strongly dependent on the sample structure for a large non-isolated sample, such as a living body, due inter alia to non-uniform radiation penetration into the large sample.
Thus although the OXI method requires calibration data, obtained for a range of radical and oxygen concentrations in a fluid sample (e.g. blood) which corresponds to the body fluid in which oxygenation is to be determined and at a pre-set temperature (e.g 37° C.), further data manipulation is required in order to extract the in vivo oxygen concentrations from the OMRI signals detected for the sample.
The calibration data are generated ex vivo by determining Overhauser enhancement values for the radical in the selected body fluid, at the selected temperature and at a range of oxygen (and preferably also radical) concentrations. The intrinsic esr relaxation times for the radical can be determined, under the same conditions, using a conventional esr spectrometer equipped with a temperature controller, with the oxygen concentration being determined using a method known to produce accurate and reproducible results (see Ravin et al J. Appl. Physiol. 18:784-790 (1964)).
In general, radical concentrations up to 0.2, preferably up to 1.0, especially up to 1.5 mM, and oxygen concentrations of up to 0.1, preferably up to 0.5 mM should be investigated to generate the calibration data.
Calibration of a blood sample at 37° can be used to determine maximum Overhauser enhancement (ie. at infinite VHF power and infinite radical concentration and T 1 . Equations which relate T 1e and T 2e to the radical and oxygen concentration by a linear relationship can be derived experimentally for whatever radical is used in the method of the invention. The equations are: ##EQU1## where x, y, z, a, b, c, h, j and k (in mG) are the experimentally determinable coefficients characteristic of the chosen radical γ e is the electron gyromagnetic ratio, C rad is the radical concentration (mM), C 02 is the oxygen concentration (mM), T 1e and T 2e are electron relaxation time(s).
With this calibration data, if T 1e , T 2e or T 1e -T 2e are calculated for a pixel in the sample's OMRI image then equations (1), (2) or (3) can easily be used to determine the oxygen concentration for that pixel. The radical concentration can be determined by manipulation of the MR signals detected in the OXI method whereby to generate a radical concentration image data set.
However, the T 1e , T 2e or T 1e -T 2e values for the pixel must be extracted from the OMRI signals detected in the imaging procedure. The OMRI imaging sequence used in the OXI method may be any one of the conventional sequences. An example of one such usable sequence is shown schematically in FIG. 1. This sequence involves a VHF irradiation period (T VHF ) of approximately the same magnitude as T 1 for the water proton, and a single echo of time TE much less than T 2 . Pixel intensity (I) is then given by equation (4):
Iα(1-exp(-T.sub.VHF /T.sub.1)) (4)
During VHF irradiation, dynamic proton polarization <I 2 > occurs The steady state is governed by the Overhauser equation (5) ##EQU2## where S 0 /I 0 is equal to 658 for an electron: proton dynamic nuclear polarization (I, here represents the equilibrium magnetisation),
k is the coupling factor (equal to 1/2 at low field),
f is the leakage factor,
and (S 0 -<S 2 >)/S 0 is the degree of saturation (SAT) of the electron spin transition).
The leakage factor f is given by equation (6) ##EQU3## (where r is the relaxivity of the radical;
C rad is the radical concentration, and
T 10 is the proton relaxation time T 1 in the absence of the radical).
The pixel intensity of the final image is given by equation (7)
Iα(1-exp (-T.sub.VHF /T.sub.1)) (1-329rC.sub.rad T.sub.1 SAT)I.sub.0( 7)
(where I 0 is the intensity of the native image pixel).
As can be seen from a Taylorian expansion of the exponential function in equation (7), provided that T VHF is significantly less than T 10 , T 1 disappears to a first order. SAT depends on the strength of the exciting VHF field B 10 and obeys the basic Bloch equations. Where the esr transition is a single Lorentzian this means that SAT is given by equation (8) ##EQU4## (where α is a conversion factor;
P is the VHF power; and
Δω is the distance from resonance of the off-resonance VHF excitation frequency (where an on-resonance frequency is used, Δω is of course zero)).
The conversion factor α is strongly spatially variant in in vivo large sample images, and thus knowledge of P, SAT, γ e and Δω is not in itself sufficient to enable oxygen concentration to be determined.
In most cases, moreover, the ear transition will not be a single Lorentzian due to residual magnetic couplings within the radical molecule. Where, as in the case with narrow esr linewidth radicals such as the trityls mentioned herein, the coupling constants are much smaller than the linewidth, the resonance lineshape will become a Voigt function and SAT will be the integral of all off-resonance values weighted by a Gaussian intensity function as in equation (9) ##EQU5## (where ΔH PP G and ΔH PP L are the first derivative peak-to-linewidth of the Gaussian and Lorentzian functions and in field units ΔH is the off-resonance field).
Equations (8) and (9) apply to single esr peaks homogeneously or in homogeneously broadened respectively. For well separated peaks, with large couplings, the saturation degree will be reduced by a factor corresponding to the far-off-resonance fraction.
In the OXI method, the data manipulation will in general be to fit SAT as determined on a pixel-by-pixel basis to one of equations (8) or (9) and thereby extract T 1e , T 2e or T 1e -T 2e , again on a pixel-by-pixel basis so permitting pixel oxygen concentration to be calculated from the experimentally determined equations (1), (2) and (3).
In one preferred embodiment of the method of the invention, data manipulation is-effected to calculate esr linewidth based on inhomogeneous broadening (equation (9)).
At its most elementary level, this method requires three OMRI images to be generated. These however can be, and preferably are, supplemented with further images recorded off-resonance, and also preferably are supplemented by images recorded with different irradiation times and native images.
In the elementary version of the method images A, B and C are recorded as follows:
A: VHF power P A . Δω=0 (i.e. on-resonance) ΔH=O. Irradiation time T VHF =T VHF1
B: VHF power P B (≠P A ). Δω=0. Irradiation time T VHF =T VHF 1
C: VHF power P C (e.g.=P A or =P B ) Δω≠0 (i.e. off-resonance) ΔH≠O (e.g. 100-200 mG). Irradiation time T VHF =T VHF1
Under these conditions, pixel intensity can be written as; ##EQU6## (where A=Gain x proton density×rC rad T 1 ×(1-exp(-T VHF /T 1 )) for rC rad T 1 >>1
(Gain is the system gain factor and proton density is the proton density of the pixel);
and B=Gain×proton density×(1-exp(-T VHF /T 1 )).
Equation 10 contains five unknowns :T 1 , proton density, C rad , ΔH PP L= 2/.sub.√3γ.sbsb.e - T .sbsb.2e and αT 1e .
With a large enhancement (e.g. about 10), short T VHF1 relative to T 1 and essentially uniform proton density in the fluid medium in which the radical is distributed, B can be omitted and the three unknowns
C rad , ΔH PP L and αT 1e can be fitted on a pixel-by-pixel
basis from the three values of I obtained from images A, B and C respectively. Radical concentration (C rad ) can then be determined by scaling A with Gain and r to yield a radical concentration image. Using the determined value of Δ PP L and the radical concentration image, the pp oxygen concentration image can then be calculated from equation (1).
A more accurate determination of oxygen concentration can be made using this method if two further images are generated, one image D on-resonance, at power P A and at irradiation time T VHF =T VHF2 (where T VHF2 ≠T VHF1 , e.g. T VHF2 =2×T VHF1 ), and the second image E without VHF stimulation, using conventional MR with repetition time TR=T VHF1 . Image E gives the native intensity I 0 for the pixels.
From the five values for pixel intensity all five unknowns can be calculated, again yielding a concentration image an PP ΔH L from which an oxygen concentration image can be determined using equation (1).
In this method, if reference samples containing body fluid and radical, are disposed about the sample surface (e.g. tubes of blood containing the radical at known concentration), the oxygen concentration image can be adjusted to express concentration even more accurately.
A further preferred embodiment of the method takes advantage of the greater sensitivity to oxygen is concentration of equation (3), i.e. of the product T 1e -T 2e . This method however requires α, which gives the VHF magnetic field at the pixel, to be determined.
In this further method, oxygen concentration and radical concentration images are calculated from three or more images as above, a 1/ T 1e image is calculated from these images and an α-image is calculated by multiplying the 1/ T 1e image by ΔT 1e as determined. The α-image is then smoothed using for example a polynomial function. It is preferred that reference samples be disposed about the sample under investigation as discussed above. If this is done then the smoothing of the α image can be achieved using a smoothing function with fixed values at the reference sample sites. This reduces statistical error in the images, is justified as the spatial variance of α is slow and, with fixed reference points, produces an accurate α image.
Using this α-image, the product of ΔH L PP wand 1/ T 1e can be calculated and from this (which is dependent on 1/ T 1e -T 2e ) and the radical concentration image, a more precise oxygen image can be calculated.
If reference sample tubes are not used, then the smoothed α-image can still be calculated but in this event the α-values determined are preferably used in the calculation of the three (or five) variables from the detected OMRI images with a further smoothed α-image being calculated from the resulting 1/ T 1e image and with the procedure being repeated until successively generated α-images are essentially unchanged (i.e. the procedure converges to a best-fit).
Whilst for radicals having a large esr linewidth the Lorentzian model is an accurate approximation for the lineshape, in the case of narrow esr linewidth radicals more precise analysis of the lineshape is called for and leads to a more accurate determination of the oxygen concentration.
In allowing the spatial variation of the VHF magnetic field to be calculated, the further method described above yields an absolute quantification of the longitudinal relation time (or the product of the longitudinal and transverse relaxation time). The longitudinal relaxation time (and even more so the product of the longitudinal and transverse relaxation rates) is more sensitive to oxygen and so this method overall is the more sensitive technique.
Although the above described methods have focused on the use of voigt functions to calculate the various unknown parameters, the OXI method may equally involve the use of Lorentzian functions where these are an accurate model of the ear lineshape and such a method forms a further embodiment of the invention. For example, in large linewidth radicals the effects of inhomogeneity may be neglected and the lineshape will essentially be Lorentzian. Thus in this preferred embodiment, the data manipulation step will essentially amount to fitting SAT (as determined on a pixel-by-pixel basis) to equation (8), extracting T 1e , T 2e and T 1e -T 2e on a pixel-by-pixel basis thereby permitting oxygen concentration to be determined from empirical relationships such as equations (1), (2) and (3).
In practice, it may be necessary to compensate for flow effects in the method of the invention and the appropriate steps will be known to those skilled in the art. Other parameters such as for example sample viscosity, pH, temperature, radical self-broadening, etc. are typically only secondary effects and thus may be neglected when compared to the first order effects of paramagnetic oxygen in the method of the invention. Radical self-broadening is however corrected for in equations 1 to 3.
Generally speaking, for use in the OXI method it is preferred for the radical to be stable under physiological conditions with a sufficiently long half life (at least one minute, preferably at least 30 minutes) and a long electronic relaxation time and good relaxivity. It will be apparent from the discussion of the OXI method that the sensitivity of the oxygen measurement will be improved with radicals having narrow linewidth esr transitions, e.g. up to 500 mG, preferably less than 150 mG, especially less than 60 mG.
Preferably, the radical selected for use in the OXI method should distribute substantially into the extracellular fluid (i.e. should be an ECF agent) since the effects of paramagnetic iron (e.g. the iron within the red blood cells) may be avoided there.
Another preferred characteristic of the radical chosen for use in the OXI method is that they should have a low self-broadening effect, preferably less than 100 mG, especially preferably between 0 and 50 mG per mM of the radical itself.
The radical compounds according to the invention may be prepared from their non-radical precursor compounds by conventional radical generation methods. Suitable non-radical precursor compounds include the corresponding triaryl methanes, triaryl methyl halides and triaryl methanols, and derivatives, e.g. ethers, of the triaryl methanols.
In a further aspect the invention provides a process for the preparation of the radical compounds according to the invention which comprises subjecting a radical precursor therefor to a radical generation step and optionally subsequently modifying the substitution on the aryl moieties, e.g. by oxidation or reduction. By such modification for example sulphide substituents, (e.g. --SCH 3 or --SCH 2 COOEt) may be oxidized to the corresponding sulphones so avoiding problems of acidic hydrogens prior to radical formulation. Similarly lipophilic substituents (such as --SCH 2 COOEt) may be reduced to corresponding hydrophilic substituents (e.g. --SCH 2 CH 2 OH).
The radical-precursor conveniently contains a group displaceable to produce a radical eg. an OH, Hal, H, COOH, --COO.O.CO.C-- or --C.NN.C-- group. Methods for preparing radical compounds from these precursors are disclosed in inter alia WO-A-91/12024 and WO-A-96/39367.
The non-radical precursors may themselves be prepared by methods conventional in the art and a number of suitable methods are described in WO-A-91/12024 and WO-A-96/39367.
Radicals with long half lives in aqueous solution, for example at least one hour, preferably ten days, more preferably fifty days and especially preferably at least one year are particularly desirable for use in in vivo imaging.
For use in OMRI in general or the OXI method, the radical compounds according to the invention are physiologically tolerable or in a physiologically tolerable form (eg. in solution, encapsulated or as a precursor). Conveniently the compounds are formulated into contrast media together with conventional pharmaceutical carriers or excipients. Contrast media manufactured or used according to this invention may contain, besides the radical (or the non-radical precursor where radical formation is to be effected immediately before administration or in situ), formulation aids such as are conventional for therapeutic and diagnostic compositions in human or veterinary medicine. Thus the media may for example include solubilizing agents, emulsifiers, viscosity enhancers, buffers, etc. The media may be in forms suitable for parenteral (e.g. intravenous) or enteral (e.g. oral) application, for example for application directly into body cavities having external voidance ducts (such as the gastrointestinal tract, the bladder and the uterus), or for injection or infusion into the cardiovascular system. However solutions, suspensions and dispersions in physiological tolerable media will generally be preferred.
Radicals which are relatively unstable or insoluble in the sample environment may be encapsulated, e.g. in gastric juice resistant capsules containing a medium in which they are stable. Alternatively, the radical may be presented as an encapsulated freeze dried powder in a soluble capsule. Such formulations might conveniently be dissolved shortly before in vivo use.
For use in in vivo diagnostic imaging, the medium, which preferably will be substantially isotonic, may conveniently be administered at a concentration sufficient to yield a 1 micromolar to 10 mM concentration of the free radical in the imaging zone; however the precise concentration and dosage will of course depend upon a range of factors such as toxicity, the organ targetting ability of the contrast agent, and the administration route. The optimum concentration for the free radical represents a balance between various factors. In general, optimum concentrations would in most cases lie in the range 0.1 to 100 mm, especially 0-2 to 10 mM, more especially 0.5 to 5 mM. Compositions for intravenous administration would preferably contain the free radical in concentrations of 10 to 1000 mM especially 50 to 500 mM. For ionic materials, the concentration will particularly preferably be in the range 50 to 200 mM, especially 130 to 170 mM and for non-ionic materials 200 to 400 mM, especially 290 to 330 mM. For imaging of the urinary tract or the renal or biliary system however, compositions may perhaps be used having concentrations of for example 10 to 100 mM for ionic or 20 to 200 mM for non-ionic materials. Moreover for bolus injection the concentration may conveniently be 0.1 to 100 mM, preferably 5 to 25 mM, especially preferably 6 to 15 mM.
The present invention will now be further illustrated by the following non-limiting Examples (percentages, parts and ratios are by weight and temperatures are in degrees Celsius unless otherwise stated).
EXAMPLE 1
Benzo[1,2-d:4,5-d']bis(1,3)dithiole-2,2,6,6-tetracetic acid ethyl ester.
The reaction was performed in dry flask under argon atmosphere. 1,2,4,5-Benzotetrathiole (74 g, 0.359 mol) and diethylacetone dicarboxylate (195.5 ml, 1.076 mol) were mixed with dichloromethane (3500 ml) and the mixture was cooled to -10° C. Fluoroboric acid (197.7 ml, 1.434 mol) was added and the cooling bath was changed to an icebath. The mixture was stirred at 0° C. for 90 minutes and then poured into solid sodium carbonate (300 g) under vigorous stirring. The slurry was filtered and the filtrate was evaporated to dryness. The solid residue was triturated with heptane (2×250 ml) and dried in a stream of air.
Yield: 138.6 g (67%)
1 H NMR (CDCl 3 ) 6.97 (s, 2H), 4.16 (q, J=7.2 Hz, 8H) 3.49 (s, 8H) 1.26 (t, J=7.2 Hz, 12H).
EXAMPLE 2
2,2,6,6-Tetra(hydroxyethyl)benzo[1,2-d:4,5-d']bis(1,3)dithiole.
A dry flask under argon atmosphere was charged with diethyl ether (2600 ml) and LiAlH 4 (21.2 g 0.56 mol) Benzo[1,2-d:4,5-d']bis(1,3)dithiole-2,2,6,6-tetraacetic acid ethyl ester (80.2 g, 0.139 mol) was added and the mixture was refluxed for 26 h. The mixture was cooled to ambient temperature and ethanol (165 ml) was carefully added followed by water (410 ml). The ether was decanted off and the white precipitate was stirred with water (3300 ml) to give a slurry. After acidification with hydrochloric acid the slurry was filtered and the crude product was washed with water and dried.
Yield: 55.0 g (97%)
1 H NMR (DMSO-d 6 ): 7.19 (s, 2H), 4.64 (t, J=5.7 Hz, 4H) 3.56 (q, J=5.7 Hz, 8H), 2.22 (t, J=6.3 Hz)
EXAMPLE 3
2,2,6,6,-Tetra(t-butoxyethyl)benzo[1,2-d:4,5-d']bis(1,3)dithiole
A dry flask under argon was charged with 2,2,6,6-tetra(hydroxyethyl)benzo[1,2-d:4,5-d']bis(1,3)dithiole (50.3 g, 0.124 mol), tetrahydrofuran (1200 ml) and isobutene (300 ml). Trifluoromethane sulphonic acid (21.8 ml, 0.248 mol) was added over 1 minute and the mixture was stirred for 1 h. The reaction mixture was poured into solid sodium carbonate (750 g) under vigorous stirring. After filtration through a silica pad the filtrate was evaporated to dryness and the solid residue was recrystallized from ethanol to give white needles.
Yield: 61.6 g (79%).
1 H NMR (CDCl 3 ): 6.95 (s, 2H), 3.56 (t, J=6.6, 8H) 2.34 (t, J=6.6 Hz, 8H) 1.18 (s, 36H)
EXAMPLE 4
2,2,6,6-Tetra(t-butoxyethyl)4-iodo-benzo[1,2-d:4,5-d']bis(1,3) dithiole
A dry flask under argon was charged with 2,2,6,6-tetra(t-butoxyethyl)benzo[1,2-d:4,5-d']bis(1,3)dithiole (60.0 g, 95.08 mmol) and dry tetrahydroturan (2000 ml). The mixture was cooled to -20° C. and n-Butyl lithium (76 ml of a 2.5 M solution in hexane, 0.19 mol) was added over 3 minutes. The mixture was stirred for 20 minutes at -20° C. and then a solution of iodine (120 g, 0.475 mol) in tetrahydroturan (500 ml) was added. The reaction mixture was poured into an aqueous sodium bisulphite solution and extracted with diethyl ether. The organic phase was washed once with an aqueous solution of sodium bisulphite and once with brine, dried (MgSO 4 ) and evaporated.
The product was purified by chromatography on silica gel using a mixture of CH 2 Cl 2 and ethyl acetate as the eluent.
Yield: 35.7 g (51%).
1 H NMR (CDCl 3 ): 6.87 (s, 1H), 3.57 (t, J=6.6 Hz, 8H) 2.35 (t, J=6.6 Hz 12 H)
EXAMPLE 5
Tris(2,2,6,6-tetra-(t-butoxy-ethyl)benzo[1,2-d:4,5-d']bis(1,3)dithiole-4-yl)methanol.
A dry flask under argon was charged with 2,2,6,6-tetra(t-butoxyethyl)4-iodo-benzo[1,2-d:4,5-d']bis(1,3)dithiole (29.0 g 38.3 mmol) and dry diethyl ether (520 ml). The mixture was cooled to -78° C. and n-butyl lithium (15.3 ml of a 2.5 M solution in hexane, 38.3 mmol) was added and the cooling bath was removed. After 30 minutes an etherial solution (0.319 M) of diethyl carbonate (40 ml, 12.76 mmol) was added dropwise over 120 minutes. Ten minutes after complete addition, the mixture was poured into aqueous NaH 2 PO 4 and extracted with diethyl ether (2×250 ml). The organic phase was washed with water, dried (MgSO 4 ) and evaporated. The product was purified by chromatography on silica gel using a mixture of C 2 Cl 2 and acetonitrile as the eluent.
Yield: 15.7 g (64%).
1 H NMR (CDCl 3 ): 7.07 (s, 3H), 6.57 (s, 1H), 3.30-3.60 (m, 24H), 2.10-2.50 (m, 24H), 1.12-1.17 (m, 108H).
EXAMPLE 6
Tris(8-hydroxycarbonyl-2,2,6,6-tetra-(t-butoxy-ethyl)benzo[1,2-d:4,5-D']bis(1,3)dithiole-4-yl)methanol
A dry flask under argon atmosphere was charged with N,N,N',N'-tetramethylethylene diamine (12.5 ml) and tris(2,2,6,6-tetra-(t-butoxyethyl)benzo[1,2-d:4,5-d']bis(1,3)dithiole-4-yl)methanol (960 mg, 0.5 mmol). The mixture was cooled to -20° C. and n-butyl lithium (3.0 ml of a 2.5 M solution in hexane, 7.5 mmol) was added over 2 minutes. The mixture was allowed to reach ambient temperature and after 1 h the mixture was heated to 40° C. and kept at this temperature for 20 minutes. The mixture was then transferred to a dry flask containing an excess of carbon dioxide (s) and was then left to reach ambient temperature. The reaction mixture was taken up in water (200 ml) and ether (150 ml) and the phases were separated. The organic phase was extracted once more with water (100 ml) and the combined aqueous phases were acidified to pH 2 and extracted with ether (100 ml). The organic phase was dried (MgSO 4 ), evaporated and the product was purified by preparative HPLC.
Yield: 315 mg (31%)
1 H NMR (DMSO): 7.03 (s, 1H), 3.18-3.58 (m, 24H), 1.95-2.30 (m, 24 H) 0.96-1.09 (m, 108H).
EXAMPLE 7
Tris(8-carboxy-2,2,6,6-tetra-(hydroxyethyl)benzo[1,2-d:4,5-d']bis(1,3)dithiole-4-yl)methyl sodium salt.
To a solution of trifluoromethane sulphonic acid (8.48 ml) in acetonitrile (64.0 ml) and dichloromethane (50.0 ml) at ambient temperature was added a solution of tris(B-hydroxycarbonyl-2,2,6,6-tetra-(t-butoxyethyl)benzo[1,2-d:4,5-d']bis(1,3)dithiole-4-yl)methanol (300 mg, 0.15 mmol) in acetonitrile (8.0 ml) and dichloromethane (8.0 ml). The mixture was stirred for 7 minutes and a 26 mM solution of tin chloride (5.2 ml, 0.14 mmol) was added After 4 minutes ice cold 1 M aqueous sodium hydroxide (96 ml) was added and the phases were separated and the aqueous phase containing the product was collected. The pH was adjusted to pH 2 and the solution was subjected to preparative HPLC. The collected fractions was evaporated to eliminate acetonitrile and the aqueous solution was poured on a pad packed with C-18 material. The pad was washed with deionized water and the product was eluted with ethanol and evaporated to dryness. To the residue was added water (5 ml) and the pH was carefully adjusted to pH 7 with diluted hydrochloric acid and the mixture was lyophilized.
Yield: 37.6 mg (18%)
ESR (1.0 mM in H 2 O, 100 G): singlet, linewidth 160 mG. | Novel triarylmethyl free radicals, their use as image enhancing agents in MRI, in particular to their use in Overhauser enhanced MRI of a sample for determining oxygen concentration of said sample. | 0 |
BACKGROUND OF INVENTION
[0001] The invention is related to a telephone comprising means of memorization or indication of data related to incoming and/or outgoing calls.
[0002] Telephones are frequently provided with a memory to store information about incoming and/or outgoing calls.
[0003] For incoming calls, the calling number is frequently memorized (if it is transferred on the line) together with the date and time of the call, and if the call was answered, together with the duration of the conversation or more generally the connection. A telephone may also comprise an indicator such as a writing on a screen or a flashing lamp, to show that a call was made and that it was not answered. In this case, the indicator disappears when the user performs a step to show that he become aware of the call.
[0004] It is also standard practice to memorize outgoing calls with their dates and durations. In particular, this feature makes it possible to check that invoiced amounts for telephone communications are correct.
[0005] This type of telephone is frequently used with other telephones on the same line, in other words with the same number, that may or may not comprise memorization or indication means. For example, the telephone with means of memorizing incoming and/or outgoing calls may be located in the main room of a home, whereas secondary telephones (cordless or with cord) are located in other rooms.
SUMMARY OF THE INVENTION
[0006] The invention is a result of the observation that the memorized or indicated information may not be reliable when a telephone with a memorization or indication device for memorizing or indicating incoming and/or outgoing calls is used with other telephones on the same line. Information about incoming calls is correct only when the call is answered on the main telephone (the telephone on which the memorization or indication means are installed). Similarly for outgoing calls, the memorized information is only correct when these calls are all made from the main telephone and do not terminate on another telephone.
[0007] If an incoming call is answered on a secondary telephone, the main telephone will indicate that the call was not answered. If the communication is made on the main telephone and is continued on a secondary telephone, the displayed time will be the time of the communication on the main telephone and not the total time.
[0008] When the main telephone is provided with a memorization device for memorizing called numbers and the duration of the communications, and when a call is dialed on the main telephone and is continued on a secondary telephone, the recorded time is the time of the call made starting from the main telephone and does not include the duration of the communication that is continued on the secondary telephone. Furthermore, if an outgoing call is dialed from a secondary telephone, the data for this call are not recorded.
[0009] To solve these problems of reliability in memorizing or indicating data related to incoming and/or outgoing calls when a telephone is connected to a line that can be fitted with other telephones called secondary telephones, the invention includes a telephone that comprises:
[0010] a device for recording data related to incoming and/or outgoing calls, and
[0011] a line state detector,
[0012] wherein the recording data about incoming and/or outgoing calls takes into account the signal provided by the line state detector and therefore communications made through the secondary telephone(s) connected to the same line.
[0013] Thus in the case of an incoming call, if the main telephone comprises an unanswered indicator, this indicator may be deactivated when the answer is made on a secondary telephone. In accordance with an embodiment of the present invention, the telephone records the duration of incoming and/or outgoing calls, this recorded time is reliable since it takes account of secondary telephones as result of the signal detected by the line state detector.
[0014] If the main receiving telephone comprises a memorization device for memorizing the duration of received calls, and if the answer is made on a secondary telephone, the recorded duration will be the duration of the actual communication independently of which telephone(s) was (were) used to answer the call. If the telephone is provided with an unanswered call indicator, means are provided to deactivate this indicator when the line state detector indicates that the line is busy, in other words a call is being answered.
[0015] If the telephone comprises a memorization device for memorizing the duration of outgoing calls, possibly with the corresponding numbers when a call is dialed from this telephone, the duration of the call that is recorded corresponds to the total duration, since the end of the call is determined by the line state detector that outputs a signal to stop counting the duration of an outgoing call when the line state detector outputs a signal indicating that the line has changed from the busy state to the ready state.
[0016] In one embodiment of a telephone comprising a memorization device for memorizing calling numbers and/or the duration of calling communications, the telephone comprises a called number detector such as a DTMF decoder so that it can provide information about called numbers even when the call is dialed from a secondary telephone.
[0017] A called numbers detector can be made using filters and corresponding programming of a processor.
[0018] For example, the line state detector can be a detector comprising means of measuring the line voltage or a detector to measure the line activity, in other words a means of measuring the AC signal on the line.
[0019] The invention can increase the reliability of data about incoming and/or outgoing calls without complicating the means of making the telephone. In particular, line state detectors are often provided in telephones for other purposes. Furthermore, calling and/or called numbers are usually managed using a microprocessor or micro controller. In this case, the invention requires that the processor is reprogrammed to take account of the line state detector, in particular such that communication durations are the real durations, in other words they are independent of which telephone was used for communication on the line concerned.
[0020] In this embodiment, the software to be added to make the invention may be downloaded through the telephone line.
[0021] The invention thus usually relates to a telephone comprising a device for memorizing or indicating data related to incoming and/or outgoing calls; this telephone comprises a detector outputting a line state signal to a memorization device or a indication device such that the memorized or indicated data depend on the state of the line.
[0022] According to one embodiment, a device for memorization or indication comprise an unanswered incoming call indicator that remains active until an incoming call has been answered, failure to answer the call being determined from the line state signal output by the detector.
[0023] In one embodiment, the telephone comprises a device for memorizing communication durations for incoming calls comprising means determining the duration that elapses for these calls between two line state changes. In this case, memorization or indication device may comprise means of memorizing the received numbers.
[0024] According to one embodiment, the memorization or indication device memorizes outgoing call durations, thereby determining the duration that elapses for these calls between two line state changes. In this case, the memorization or indication device is operable to memorize called numbers. These numbers may be detected by a detector of the dialed number on the line, such as a DTMF decoder in order to memorize numbers dialed from other telephones connected to the same line.
[0025] In one embodiment, the telephone comprises a processor and a device for receiving programming signals over the telephone line to be loaded into the processor memory so that the processor is capable of returning memorized or indicated data as a function of the state of the line.
[0026] The invention also relates to a set of at least two telephones including one telephone as described above and one telephone without memorization or indication means.
[0027] Other characteristics and advantages of the invention will become clear in the description of some embodiments with reference to the attached drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] [0028]FIG. 1 represents a telephone installation comprising a main telephone and secondary telephones,
[0029] [0029]FIG. 2 is a diagram showing a telephone according to an embodiment of the present invention, and
[0030] [0030]FIG. 3 is a diagram showing a telephone according for another embodiment of the present invention.
DESCRIPTION OF THE INVENTION
[0031] [0031]FIG. 1 diagrammatically shows a telephone installation comprising a telephone line 10 to which a telephone 12 is connected, the telephone 12 comprises a memorization device 14 for memorizing data about incoming and/or outgoing calls. In the remaining description, this telephone 12 with the memorization device 14 will be referred to as the main telephone 12 . Secondary telephones 16 and 18 are connected in parallel on the same line 10 . The main telephone 12 and/or the secondary telephones 16 and 18 may be of the cordless type. For example, telephone 16 is a cordless telephone, in other words there is a base 16 1 connected by wire to the line 10 , while the telephone itself 16 2 is cordless and communicates with base 16 1 .
[0032] The memorization device 14 is capable of performing at least one of the following three functions:
[0033] The first function is memorization of incoming calls that had not been answered. In this case, an indicator such as a flashing light signal remains active and must subsequently be deactivated manually.
[0034] The second function is an indication of the communication duration for incoming calls, and/or the numbers of these calls (when they are received).
[0035] The third function is the communication duration for outgoing calls, and/or the recording of the corresponding numbers.
[0036] For each of these three functions, the memorization device 14 does not provide reliable data if the communication is made entirely or partly from a secondary telephone. Thus for the first function, if the main telephone 12 is not picked up, and if only one of the secondary telephones 16 or 18 is picked up to answer an incoming call, then the unanswered incoming call indicator remains active.
[0037] When the duration of incoming calls is recorded, this duration only corresponds to the duration of the action taken by the main telephone 12 . For example, if the user answers an incoming call on the main telephone 12 , and then continues on the secondary telephone 16 or 18 after hanging up the main telephone 12 , the recorded time will not be the duration of the call, but it will be the time between when the line is taken and when use of the main telephone 12 terminates.
[0038] If an outgoing call is started from the main telephone 12 and terminates on the secondary telephonel 6 or 18 , and the main telephone was hung up in the meantime, the duration of the outgoing call that will be recorded will be the time corresponding to the time during which the main telephone 12 takes the line 10 . Thus, the data output by the memorization device 14 will not be correct. Finally, if an outgoing call is made solely from the secondary telephone 16 or 18 , no data will be recorded in the main telephone by the memorization device 14 .
[0039] The present invention records reliable data on the main telephone 12 , even if the secondary telephone 16 or 18 is involved in the incoming and/or outgoing communication.
[0040] In the embodiment of the present invention shown in FIG. 2, the telephone 12 comprises a module 14 , for memorization and display of data about incoming calls. Therefore, the telephone 12 comprises an incoming calls detector 22 , the output of which is connected to an input to module 14 1 . The telephone 12 also comprises a time-dater 24 that provides date and duration data to module 14 1 . The telephone 12 also comprises a memory 26 providing a telephone directory containing telephone numbers, and other information about the telephone numbers.
[0041] The telephone 12 also comprises an unanswered calls notification light 28 that is activated by an output signal from module 14 1 . Another type of indication can be provided instead of a light, such as on a display.
[0042] According to the present invention, the telephone 12 comprises a line state detector 30 that outputs a signal representative of the line busy state. This signal supplied by the detector 30 is a line state indication and is not an indication that the line is or is not taken by telephone 12 . In other words, the detector 30 outputs a line busy signal when any of the telephones connected to the line is picked up. It supplies a line free signal when all telephones connected are hung up.
[0043] The line state detector 30 is made in a known manner, and is either of the type that detects the DC voltage of the line 10 , or of the type that detects activity on this line 10 (AC signal level).
[0044] The signal output by detector 30 is applied to an input 32 of module 14 1 to prevent the light 28 from being activated or lit up when the line changes from a free state to a busy state, in other words when the telephone 12 or a secondary telephone is picked up following an incoming call.
[0045] The signal output on the input 32 is also used to determine the real duration of the communication, regardless of which telephone is used to answer it. Thus, the displayed duration will be the time between when the line is taken (line busy start) and when the line is no longer taken (all telephones are hung up).
[0046] Under these conditions, if an incoming call is answered by a secondary telephone, the duration of the communication will be recorded in the main telephone 12 . Similarly, if the main telephone was used to answer and a secondary telephone was used afterwards, the recorded time will always be the time of the actual communication, in other words the total line busy time.
[0047] Conventionally, the time-dater 24 is used to determine communication durations and dates. The directory memory 26 is used in a manner known in itself to memorize the name of the caller when the calling number is already in the directory 26 and when the name is not sent by the telephone exchange on the line.
[0048] The telephone 40 shown in FIG. 3 comprises means of memorizing data related to outgoing calls. It comprises a module 42 for memorizing these data and to control their display. The module 42 receives information from a time-dater 24 and from a directory 26 similar to the memory with the same reference number in the embodiment described with FIG. 2.
[0049] The dialer 44 on telephone 40 outputs a number signal as an input to module 42 . This called number is memorized by the module 42 with the called party's name if this number is in the directory 26 .
[0050] The time-dater 24 can memorize data or information, such as the called dates and call durations.
[0051] According to the invention, the telephone 40 comprises a line state detector 30 . This detector is identical to the detector with the same reference in the embodiment shown in FIG. 2. The signal output by the detector 30 is applied to an input 46 of the module 42 such that the data memorized to display outgoing communications information are independent of the telephone (i.e., main or secondary) from which the calls were made or dialed, and are only dependent on the state of the line. Thus, the recorded duration is the duration elapsed between when the line was taken in the first place and when the line was released.
[0052] If the call is dialed from the main telephone 40 and is terminated from a secondary telephone, the module 42 records the called number and at the same time the real duration of the communication and not the duration corresponding to the part of the communication done on the main telephone 40 only. If the call is dialed from a secondary telephone, the total duration and the communication may be recorded.
[0053] To enable a number called from a secondary telephone to be recorded in the main telephone 40 , a variant of this telephone 40 is shown with dashed lines in FIG. 3 comprising a called number detector 50 for detecting a called number on the line 10 from another telephone, i.e., secondary telephone. For example, the detector 50 can be a DTMF decoder.
[0054] Regardless of which embodiment is used, the invention makes it possible to make data recorded about incoming and/or outgoing calls dependable, using simple and economic means. When a line state detector 30 is provided in a telephone for a function other than that described for this invention, and when the telephone also comprises a processor, the functions to make the data dependable may be downloaded into the processor in the form of one or more programs. This downloading may be done through the telephone line 10 .
[0055] The detector 50 , particularly a DTMF decoder, can also be made using a processor. | The present invention relates to a telephone comprising a device for memorizing or indicating of data related to incoming and/or outgoing calls. The telephone comprises a detector for supplying a line state signal to memorization or indication device, which memorizes or indicates the data as a function of the state of the line. Thus, the memorized or indicated data take account of calls received on or sent from a secondary telephone. | 7 |
This application is a continuation, of application Ser. No. 07/318,236, filed Mar. 3, 1989 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to microfilm cameras and particularly to a microfilm camera capable of photographing successively on a microfilm a large number of originals set in a photographing position.
2. Description of the Related Art
In general, a microfilm camera photographs an original when a photographing switch is turned on after the original has been set in a photographing position on a document platen. After an end of photographing of an original, another original is set in the photographing position and thus photographing operation is performed successively.
Such photographing operation involves disadvantages as described below.
It happens that photographing is interrupted after an original has been set. In such a case, it is sometimes unclear whether the set original has been photographed or not after the interruption.
In an electrophotographic copying apparatus or the like, whether the original has been copied or not can be confirmed readily by checking the copy obtained. However, in a conventional microfilm camera, it can be confirmed only after development of the film whether an original has been photographed or not. In addition, the same original is photographed repeatedly by mistake due to uncertain memory of the operator or errors such as failure to photograph an original occur.
Japanese Patent Laying-Open Gazette No. 164730/1982 discloses the following technique.
According to this gazette, a microfilm camera comprises a memory device for successively storing operations of various operation switches, and a switch for reading the contents of this memory device. When it becomes necessary for the operator to confirm whether an original has been photographed or not, the contents of the memory device are successively read out by operation of the reading switch.
However, the technique disclosed in the above indicated gazette involves disadvantages as described below. When the operator desires such confirmation, it is necessary for the operator to operate the reading switch. Thus, any operation by the operator is required. On the other hand, if photographing operation is carried out with no original being set, the fact of turn-on of the photographing switch is recorded. Although it is confirmed by using the reading switch that the photographing operation has been done, it might be erroneously determined by this confirmation that an original has been photographed. Thus, errors in photographing such as failure to photograph an original would occur.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a microfilm camera capable of preventing errors photographing such as failure to photograph an original.
Another object of the present invention is to provide a microfilm camera in which no errors in photographing occur even if no particular operation is required for an operator.
Still another object of the present invention is to provide a microfilm camera capable of indicating whether an original set in a photographing position on a platen has been already photographed or not.
A further object of the present invention is to provide a microfilm camera capable of preventing the same original from being photographed repeatedly by mistake.
In order to attain the above described objects, a microfilm camera according to the present invention includes: original placing means for placing an original in a prescribed photographing position; a photographing device for photographing the original on the original placing means onto a microfilm; a detecting device for detecting presence or absence of the original in the photographing position; an input device for issuing an instruction to photograph the original; and a display device for indicating whether the original has been photographed or not, in response to outputs of the detecting device and input device.
Since the microfilm camera is thus constructed, it is indicated whether the original has been photographed or not. Accordingly, the operator can visually confirm whether the original to be photographed has been actually photographed or not. In consequence, the microfilm camera according to the present inveniton makes it possible to prevent errors in photographing such as failure to photograph an original.
According to another aspect of the present invention, a microfilm camera for photographing an original set in a photographing position onto a microfilm includes: a detecting device for detecting presence or absence of the original in the photographing position; an instructing member for instructing photographing of the original on the microfilm; and a display device for indicating information that the original is not photographed, after an elapse of a predetermined time in a state in which the instructing member does not give the photographing instruction after the detection of the presence of the original by the detecting device.
Since the microfilm camera according to the present invention includes the above described elements, the operator can confirm whether the original in the photographing position has been photographed or not, only by looking at the display portion of the microfilm camera. In consequence, errors in photographing do not occur even if the operator does not carry out any particular operation.
According to a further aspect of the present invention, a microfilm camera for photographing an original set in a photographing position onto a microfilm includes: a detecting device for detecting presence or absence of the original in the photographing position; an instructing device for instructing photographing of the original onto the microfilm; and a display device for indicating that the original has been photographed, when the instructing device gives the photographing instruction after the detection of the presence of the original by the detecting device.
Since the microfilm camera is thus constructed, the indication that the original has been photographed is given after the original set in the photographing position has been actually photographed. Accordingly, the same original is not photographed repeatedly by mistake.
According to a preferred embodiment of the invention, the display device gives the indication continuously until the detecting device detects removal of the original from the photographing position. The indication does not disappear unless the operator removes the original from the photographing position. Consequently, the same original is not photographed repeatedly by mistake.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a microfilm camera according to the present invention;
FIG. 2 is a plan view of a document platen;
FIGS. 3A and 3B are front views of a detecting device viewed from the side shown by the line III--III in FIG. 1;
FIG. 4 is a block diagram showing a control system of the microfilm camera;
FIG. 5 is a flow chart for controlling a first embodiment of a microfilm camera according to the present invention;
FIG. 6 is a flow chart for controlling of a second embodiment of a microfilm camera according to the present invention;
FIG. 7 is a flow chart for controlling a third embodiment of a microfilm camera according to the present invention;
FIG. 8 is a flow chart for controlling a fourth embodiment of a microfilm camera according to the present invention;
FIG. 9 is a flow chart for controlling a fifth embodiment of a microfilm camera according to the present invention; and
FIG. 10 is a flow chart for controlling a sixth embodiment of a microfilm camera according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing an appearance of a microfilm camera according to the invention. FIG. 2 is a plan view of the document platen of the camera.
Referring to FIG. 1, the microfilm camera, which is of a manual type, comprises: a base plate 1 for supporting the entire body of the camera, a document platen 6 provided on the base plate 1, on which an original to bephotographed is placed, a stay 2 provided at a rear end of the base plate 2, for supporting a camera head 5 and other elements, and an arm 3 fixed to the stay 2, for supporting an illumination unit 4 for illuminating an original to be photographed. The stay 2 can be expanded or retracted vertically. The camera head 5 having the shape of a sealed box comprises afeed reel for feeding a raw film, an exposure portion, a film transport mechanism, a film winding reel etc. (not shown).
The document platen 6 is located under the illumination unit 4 and its surface has marks of corner frames 7. The corner frames 7 indicate a photographing range by means of the camera head 5 and an original (not shown) is set in a photographing position within the corner frames 7.
The illumination unit 4 applies light to the original set in the photographing position. The original is photographed on a microfilm by means of a lens, a shutter, an aperture and the like in the camera head 5.As a result, the original is recorded on the microfilm as a reduced image.
A detecting device 8 is provided at the center of the area defined by the corner frames 7 of the platen 6. FIG. 3 shows front views of the detectingdevice 8 viewed from the side shown by the line III--III in FIG. 1. FIG. 3Arepresents a state in which no original exists and FIG. 3B represents a state in which an original exists.
As shown in FIG. 3A, if an original S is not set in the photographing position on the platen 6, light from a light emitting portion 81 of the detecting device 8 is diffused upward and it does not enter the light receiving portion 82. As a result, the detecting device 8 is off and it isdetermined that the original S does not exist.
If the original S is set in the photographing position on the platen 6 as shown in FIG. 3B, the light from the light emitting portion 81 of the detecting device 8 is reflected on the back surface of the original S and enters the light receiving portion 82. As a result, the detecting device 8is turned on and it is determined that the original S exists.
In the above described embodiment, the detecting device 8 is formed by a reflection type photosensor. The detecting device 8 may be formed by othersensors such as an ultrasonic sensor or a limit switch.
The microfilm camera may include a document feeder for automatically feeding the original S to the platen 6. In this case, feeding of the original S to the photographing position and removal of the original S therefrom may be detected in a transport path of the original S, making itpossible to detect presence or absence of the original S in the photographing position.
FIG. 4 is a block diagram showing a control system of the microfilm camera.Referring to FIG. 4, the control system of the microfilm camera comprises amicrocomputer 10 as the center of the system, a detecting device 8 for inputting a signal to the microcomputer 10, a photographing switch 9, a camera head 5 for carrying out prescribed operation upon receipt of an output signal from the microcomputer 10, a display portion 11 and an alarmportion 12.
The photographing switch 9 is provided at a front edge of the base plate 1 to instruct photographing of the original S onto the microfilm. When the photographing switch 9 is pressed, an instruction signal is inputted to the microcomputer 10. The microcomputer outputs drive signals to the feeding mechanism, aperture, shutter and other elements of the camera head5, so that a photographing process is executed.
The display portion 11 and the alarm portion 12 provided at the front edge portion of the base plate 1, for indicating that the original has been photographed or that it is not photographed are responsive to the signals from the microcomputer. The display portion 11 includes a light emitting device such as an LED and it is turned on or off. The alarm portion 12 is turned on to generate an alarm sound. Although both of the display portion11 and the alarm portion 12 are provided in the first embodiment, only either one of them may be provided.
In the following, operation of the microfilm camera of the first embodimentwill be described. FIG. 5 is a flow chart showing an example of control.
First, when a power switch (not shown) is turned on, initialization is effected in step S1 in FIG. 5. In step S2, it is determined by the detecting device 8 whether or not the original S is set in the photographing position of the platen 6. When the original S is placed on the platen 6, the detecting device 8 is turned on and the processing flow proceeds to step S3.
In step S3, it is determined whether a photographing instruction is issued by the photographing switch 9. If the operator turns on the photographing switch 9, the processing flow proceeds to step S4 to execute a predetermined photographing process, whereby the original S is photographed as an image on the film. Thereafter, the processing flow returns to step S2.
If the photographing instruction is not given by means of the photographingswitch 9 in step S3, it is determined whether a prescribed time has passed after the turn-on of the detecting device 8 (in step S5). If the prescribed time has not passed, the processing flow returns to step S3. Ifit is determined in step S3 that the prescribed time has passed without issuance of the photographing instruction, a display signal is applied (instep S6). Thus, the display portion 11 is illuminated and the alarm portion12 begins to generate the alarm sound, thereby indicating information that the original S is not photographed. In consequence, the operator becomes aware that the original S is not photographed.
It is determined again whether the photographing instruction for the original S is issued by means of the photographing switch 9 (in step S7). When the operator finds that the original is not photographed and turns onthe photographing switch 9, the application of the display signal stops (instep S8) and thus the display portion 11 is turned off and the alarm portion 12 stops generation of the alarm sound. After that, the photographing process is executed (in step S4).
If the operator does not turn on the photographing switch 9 in step S7 and it is determined that the prescribed time has passed after the turn-on of the display signal (in step S9), the application of the display signal stops, whereby the display portion 11 is turned off and the alarm portion 12 stops generation of the alarm sound (in step S10). Then, the processingflow returns to step S2. If it is determined in the step S9 that the prescribed time has not passed, the flow returns to step S7.
In step S9, it is determined whether or not the prescribed time has passed as described above. In place of such determination, it may be determined whether or not the detecting device 8 is off to check for change of originals S for example.
As described above, according to the first embodiment, if photographing of the original S in the photographing position is not terminated, the display/alarm is a given to indicate that the original is not photographed. Accordingly, it can be easily and readily determined whetherthe original has been photographed or not, and failure to photograph the original does not occur. As a result, the original can be photographed reliably.
In a very short time before the elapse of the prescribed time, the operatoris aware of whether the photographing of the original S is terminated or not and accordingly there is not need to give a display.
Next, the second embodiment will be described. Since the construction of the microfilm camera according to the second embodiment is the same as that in the first embodiment and only the control thereof is different, only the different points will be described. FIG. 6 is a flow chart showing the control of the second embodiment. Referring to FIG. 6, operation of the second embodiment will be described.
In the flow of FIG. 6, the procedures from the initialization in step S11 to the photographing process in step 14 are just the same as the procedures from step S1 to step S4 described above in connection with FIG.5. Therefore, the description thereof is omitted.
If a photographing instruction is not given by means of the photographing switch 9 in step S13 in FIG. 6, it is determined whether or not the original S has been removed from the photographing position of the platen 6 without being photographed (in step S15). If it is not removed, the processing flow returns again to step S13. If the original S has been removed and the detecting device 8 is turned off to determine absence of the original S, the processing flow proceeds to the next step S16.
Then, the display signal is applied. Thus, the display portion 11 is turnedon and the alarm portion 12 starts to generate the alarm sound, thereby indicating the information that the removed original S is not photographed.
After that, the processing flow proceeds to step S17 to determine whether the original S is set in the photographing position of the platen 6. More specifically, if the operator finds that the original S is not photographed and places again the original S, causing the detecting device8 to be turned on again, the processing flow proceeds to step S18 to turn off the display. Thus, the display portion 11 is turned off and the alarm portion 12 stops the generation of the alarm sound. Then, the processing flow returns to step S13 to turn on the photographing switch 9, whereby the photographing process is executed in step S14.
If it is determined in step S17 that the detecting device 8 is not turned on and it is determined in step S19 that a prescribed time has passed thereafter, the display is turned off (in step S20). More specifically, ifthe operator does not place again the original within the prescribed time, the display portion 11 is turned off and the alarm portion 12 stops the generation of the alarm sound since the photographing of the original is not required. Then, the flow returns to step S12.
If it is determined in step S19 that the prescribed time has not passed, the flow returns to step S17.
Thus, the operator can easily and readily determine according to the above mentioned information whether the original S removed from the photographing position has been photographed or not. In consequence, failure to photograph the original does not occur and photographing operation can be carried out with reliability.
The above described first and second embodiments may be both utilized in combination.
More specifically, the display may be turned on if the prescribed time has passed without turn-on of the photographing switch 9 during a period of detection of presence of the original S by the detecting device 8, or if the detecting device 8 detects absence of the original S with the photographing switch 9 being not turned on after the detecting device 8 detects presence of the original S.
In the following, the third embodiment will be described. The construction of the microfilm camera according to the third embodiment is the same as that of the first embodiment. The third embodiment is different from the first embodiment in the control thereof and the display of information "photographed". Accordingly, only the different points will be described. FIG. 7 is a flow chart showing the control of the microfilm camera according to the third embodiment.
First, when a power switch (now shown) is turned on, initialization is effected in step S21. In step S22, it is determined by the detecting device 8 whether or not the original S is set in the photographing position on the platen 6. When the operator places the original S on the platen 6, the detecting device 8 is turned on, whereby presence of the original S is detected.
Then, in step S23, it is determined whether a photographing instruction is given by means of the photographing switch 9. If the operator does not turn on the photographing switch 9, the processing flow returns to step S22. When the photographing switch 9 is turned on, the processing flow proceeds to the next step.
More specifically, the prescribed processing process is executed, so that the original S is photographed as an image on the film. In step S25, a display signal is applied and thus the display portion 11 in the third embodiment gives the display "photographed".
Thereafter, in step S26, it is determined whether the photographed originalS is removed from the photographing position of the platen 6. If the detecting device 8 is turned off to detect absence of the original S, the application of the display signal is stopped and the display portion is turned off (in step S27).
Then, the processing flow returns to step S22.
Thus, determination as to whether the original S has been photographed or not can be easily and readily made only at a glance at the display portion11 and the photographing operation can be carried out with high reliability.
Next, the fourth embodiment will be described. The construction of the fourth embodiment is the same as that of the first embodiment. However, the fourth embodiment is different from the first embodiment in the procedures of control thereof and the display given for indicating "photographed".
FIG. 8 is a flow chart showing the control of the fourth embodiment.
Referring to the flow chart of FIG. 8, the procedures from the initialization in step S31 to the turn-on of the display in step S35 are entirely the same as the procedures from step S21, to step S25 described above in conjunction with FIG. 7 and therefore the description thereof is omitted. In step S36 of FIG. 8, it is determined whether the original S photographed is removed from the photographing position on the platen 6 and if the detecting device 8 is turned off to detect absence of the original S, the processing flow proceeds to the subsequent step S37.
In step S37, it is determined whether another original S is set in the photographing position on the platen 6.
When the operator places the new original S on the platen 6 and the detecting device 8 is turned on again to detect presence of the original S, the processing flow proceeds to the subsequent step S38.
In the subsequent step S38, the application of the display signal is stopped and the display portion 11 is turned off.
Thereafter, the processing flow returns to step S33.
The above described fourth embodiment is particularly advantageous in casesin which, after the photographed S has been removed, the operator is not sure of whether that original S has been photographed or not. The display "photographed" for the removed original S is continuously in the on state until another original S is set. Accordingly, the operator can confirm easily and readily whether the original S has been photographed or not.
In the following, the fifth embodiment will be described. The microfilm camera according to the fifth embodiment has the same construction as thatof the first embodiment. It is different from the first embodiment in the procedures of control thereof and the display for the "photographed" original. Therefore, only the different points will be described.
FIG. 9 is a flow chart showing the control procedures of the fifth embodiment. Referring to FIG. 9, the control procedures of the fifth embodiment will be described.
First, when a power switch (not shown) is turned on, initialization is effected in step S41.
In step S42, it is determined whether or not a photographing instruction isgiven by means of the photographing switch 9. If the operator erroneously turns on the photographing switch 9 without setting the original S, the processing flow proceeds to step S43. In step S43, the photographing instruction by this turn-on of the photographing switch 9 is rendered ineffective and the alarm portion 12 gives an alarm sound for a predetermined period. After that, the processing flow returns to step S42.
If it is determined in step S42 that the photographing switch 9 is off, it is determined in the subsequent step S44 by means of the detecting device 8 whether or not the original S is set in the photographing position on the platen 6.
If it is determined that the original S is not set, the flow returns to step S42. However, when the original S is set, the detecting device 8 is turned on to detect the presence of the original S and the processing flowproceeds to the subsequent step S45.
In step S45, it is determined whether or not a photographing instruction isgiven by means of the photographing switch 9. If the operator does not turnon the photographing switch 9, the processing flow returns to step S44. If the photographing switch is turned on, the processing flow proceeds to thesubsequent step S46.
The prescribed photographing process is executed in step S46, whereby the original S is photographed as an image on the film. In step S47, a displaysignal is applied, whereby the display portion 11 is turned on. As a result, it is announced to the operator that the original S has been photographed.
In the subsequent step S48, it is determined whether or not a photographinginstruction is given by means of the photographing switch 9. If the operator erroneously turns on again the photographing switch 9, the processing flow proceeds to step S49. In step S49, the photographing instruction by this turn-on of the photographing switch 9 is rendered ineffective and the alarm portion produces an alarm sound for a predetermined period. Thereafter, the processing flow returns to step S48.
When it is determined in step S48 that the photographing switch 9 is off, it is determined in the subsequent step S50 whether or not the photographed original S has been removed from the photographing position on the platen 6. If the detecting device 8 is on and it is determined thatthe original S still exists, the flow returns to step S38.
If the detecting device 8 is turned off and absence of the original S is determined, the processing flow in this embodiment proceeds to the subsequent step S51, where the application of the display signal is stopped and the display portion 11 is turned off.
After that, the processing flow returns to step S42. Thus, the operator caneasily and readily confirm whether or not the original S has been photographed only by a glance at the display portion 11.
If the operator turns on again the photographing switch 9 by mistake while the display portion 11 gives the display "photographed", that is, until the original S is removed, the following procedures are executed accordingto this embodiment. The photographing instruction by this turn-on of the switch 9 is rendered ineffective as described above and an alarm is issuedin this embodiment. In consequence, repetitive photographing by mistake canbe prevented reliably.
Thus, photographing operation can be carried out with high reliability.
Next, the sixth embodiment will be described. The microfilm camera of the sixth embodiment has the same construction as that of the first embodiment. It is different therefrom only in the control procedures thereof and the display for the "photographed" original. Therefore, only the different points will be described.
FIG. 10 is a flow chart showing the control procedures of the sixth embodiment.
Referring to FIG. 10, the procedures from the initialization of step S61 tostep S69 are entirely the same as the procedures from step S41 to step S49 of the fifth embodiment described above in connection with FIG. 9 and therefore the description thereof is omitted.
In step S70 of FIG. 10, it is determined whether the photographed original S has been removed from the photographing position on the platen 6. If thedetecting device 8 is still on and the original S is determined to exist, the processing flow returns to step S68.
When the detecting device 8 is turned off and absence of the original S is determined, the processing flow proceeds to the subsequent step S71.
In step S71, it is determined whether or not a photographing instruction isgiven by means of the photographing switch 9. If the operator turns on again the photographing switch 9 by mistake, the photographing instructionby this turn-on of the switch 9 is rendered ineffective (in step S72) and the alarm portion 12 issues an alarm for a predetermined period. Then, theprocessing flow returns to step S71.
When it is determined in step S71 that the photographing switch 9 is off, it is determined in the subsequent step S73 whether another new original Sis set in the photographing position of the platen 6. When the operator sets the new original S and the detecting device 8 is turned on again to determine presence of the original S, the processing flow proceeds to the subsequent step S74.
In step S74, the application of the display signal is stopped and the display portion 11 is turned off.
The above described sixth embodiment is advantageous in cases in which, after the photographed original S has been removed, the operator is uncertain of whether the photographing switch 9 was turned on for that original S. Thus, the display of "photographed" for the removed original Sis continuously in the on state until the next new original S is set. Accordingly, the confirmation as to the turn-on of the photographing switch 9 can be made easily and readily.
If the operator turns on again the photographing switch 9 during the display of "photographed" until another new original is set, the photographing instruction by this turn-on is rendered ineffective as described above and an alarm is issued. Accordingly, repetitive photographing by mistake in such cases can be prevented reliably.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims. | A microfilm camera for photographing a plurality of originals on a microfilm is disclosed. The improved microfilm camera is provided with a display lamp for indicating that an original is left in a non-photographed state and a buzzer for issuing an alarm on that occasion. If the original non-photographed is left as it is, the display lamp turns on and the buzzer sounds. Accordingly, the original to be photographed is not left in the non-photographed state for a long period. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 61/861,957, filed Aug. 2, 2013 and claims the benefit of U.S. Provisional Application No. 61/862,447, filed Aug. 5, 2013.
BACKGROUND OF THE DISCLOSED SUBJECT MATTER
[0002] 1. Field of the Disclosed Subject Matter
[0003] The disclosed subject matter relates to tissue engineered models of cancers, including prostate cancer and Ewing's Sarcoma. Particularly, the presently disclosed subject matter relates to providing a three-dimensional decellularized bone scaffold seeded with cancer cells, such as prostate cancer cells and Ewing's sarcoma cells, and bone tissue cells.
[0004] 2. Background
[0005] Cancer research is experiencing tremendous advances in the development of genome-wide regulatory models and network-based methods that helped discover new cancer genes and new mechanisms of drug action. At the same time, there is a growing notion on how important are the environmental contributors to the initiation, progression and suppression of cancer, including the three-dimensionality, other cells, tissue matrix, molecular and physical signaling. The lack of ability to replicate in vitro the complex in vivo milieu of human cancer is a critical barrier to evaluation of the potential therapeutic targets for clinical application.
[0006] Ewing's sarcoma is a rare cancer that typically affects the bones. Most often it is found in the leg and arm bones of children, accounting for 1% of all childhood cancers. Ewing's sarcoma can be treated successfully in 50% to 75% of cases. Ewing's sarcoma is a poorly differentiated tumor of uncertain histogenesis and aggressive biologic behavior characterized by a strong membrane staining for CD99. Most prostate cancer deaths are due to metastasis into bone, and yet there is not a good model of metastatic prostate cancer: in vitro, the cancer cells rapidly lose their cancer phenotype, and in vivo the mouse bone is not permissive for cancer cell invasion.
[0007] Current experimental methods and models to study cancer growth and progression mainly utilize in vitro two dimensional (2D) co-culturing of cancer specific cell lines and other cells found local in the tumor. However, these 2D models fail to capture the true three dimensional (3D) progression of tumors and are limited in their ability to identify therapeutic targets. The shortcomings are underscored by the fact that most drugs fail to translate observed in vitro effects to in vivo studies and that only about 5% of drugs show effects in clinical trials. Numerous two-dimensional (2D) culture studies and in vivo studies have been actively pursued to further understand the complex mechanisms and the molecular pathways in prostate cancer and Ewing's sarcoma. However these models are not able to mimic the disease. Cells lose relevant properties in 2D due to the loss of physiological extracellular matrix (ECM) when cultured on artificial plastic surfaces at high serum concentrations. Studies in animal models also have their limitations. Prostate cancer and Ewing's sarcoma are human diseases and that are not accurately represented in an animal model.
[0008] Based on studies in genetically engineered mice and using clinical data, it has been established that mouse bone acts as a barrier to prostate cancer cell invasion, in contrast to the human bone that is permissive to metastasis.
[0009] Thus, there remains a need for a three dimensional model enabling more accurate modelling of cancers.
SUMMARY
[0010] The purpose and advantages of the disclosed subject matter will be set forth in and apparent from the description that follows, as well as will be learned by practice of the disclosed subject matter. Additional advantages of the disclosed subject matter will be realized and attained by the methods and systems particularly pointed out in the written description and claims hereof, as well as from the appended drawings.
[0011] To address the challenges noted above, the present subject matter provides an advanced platform technology for controllable, quantitative, long-term studies of tissue-engineered tumors, such as prostate cancer and Ewing sarcoma (ES) as clinically significant models. In accordance with the subject matter, a 3D decellularized bone scaffold seeded with cancer cells, such as prostate cancer cells and Ewing's sarcoma cells (patient derived or cell lines) and bone tissue cells is provided. Some genes up-regulated in primary Ewing's sarcoma cells are silenced in existing Ewing's sarcoma cell lines. Thus, the technology of the present disclosure has demonstrated that cancer cells such as prostate cancer and Ewing's sarcoma cell lines cultured in this 3D scaffold re-express the silenced genes, better recapitulating the original in vivo tumor phenotype. Accordingly, the scaffold can be used with cancer cell lines, such as prostate cancer and Ewing's sarcoma, to identify therapeutic targets to slow, stop, and reverse tumor growth and progression as well as predict the efficacy of potential therapeutics. The technology can also be used with patient-derived cancer cells and mesenchymal stem cells for a personalized approach to cancer treatment.
[0012] In one aspect, cancer cells are introduced into bone tissue engineered from human cells, and cultured over long periods of time with vascular perfusion, oxygen control, and mechanical loading. Culturing tumor cells in a living bone environment may recapitulate the original in vivo tumor signature.
[0013] In accordance with one method, a tissue-engineered model of Ewing's sarcoma is established. A control of oxygen supply and incorporated perfusable vasculature into the engineered ES model is provided.
[0014] In accordance with another method, a validation is provided to validate the model by assessing effects of mechanical stress and perfusion on tumor phenotype and focal adhesion genes.
[0015] Further, a validation of the advanced bioengineering platform technology for cancer research, in two modifications: (1) for high-throughput screening (96-well format) and advanced studies of tumor biology (24-well format) is provided. The present technology has an unusually high transformative potential; it enables critical advances in several areas central to cancer research, and uses pioneering approaches with potential for paradigm-shifting advances, and is based on pilot data.
[0016] In one embodiment, a cancer model is provided with a biomimetic microenvironment representing the pathophysiology of this malignancy. This is achieved by using three-dimensional (3D) instead of conventional two-dimensional (2D) cultures, with the aid of bone-engineering technology. In a 3D context, cancer cell lines modify their 2D transcriptional profile, recapitulating better the original tumor phenotype. This novel model is expected to be a powerful tool for predictive testing of anti-cancer and anti-metastatic compounds.
[0017] In some embodiments, a three-dimensional cancer model is provided. The model includes a decellularized bone scaffold and a plurality of cells arrayed on the scaffold. In some embodiments, the plurality of cells comprises cancer cells. In some embodiments, the cancer cells are metastatic cancer cells, prostate cancer cells, or Ewing's sarcoma cells. In some embodiments, the cancer cells comprise a plurality of spheroids. In some embodiments, the bone scaffold comprises a plurality of perfusion channels. In some embodiments, the plurality of cells comprises stem cells. In some embodiments, the plurality of cells comprises osteoblasts. In some embodiments, the plurality of cells comprises bone tissue cells. In some embodiments, the plurality of cells comprises patient-derived cells. In some embodiments, the scaffold is adapted for insertion in one well of a multiple well plate. In some embodiments, the scaffold is adapted for insertion in one well of a 96-well plate. In some embodiments, the scaffold is adapted for insertion in one well of a 24-well plate. In some embodiments, the scaffold has an outer region, and inner region, and a core region. In some embodiments, a first portion of the plurality of cells is arrayed in the outer region, a second portion of the plurality of cells is arrayed in the inner portion, and a third portion of the plurality of cells is arrayed in the core region. In such embodiments, the second portion is hypoxic and the third portion is necrotic.
[0018] In some embodiments, a platform for modelling cancer is provided. The platform includes a decellularized bone scaffold, an oxygen supply in gaseous communication with the bone scaffold, a vasculature in fluid communication with the bone scaffold, and a mechanical load coupled to the bone scaffold. In some embodiments, the mechanical load is adapted to apply a mechanical stress to the bone scaffold. In some embodiments, the vasculature comprises a nutrient supply.
[0019] In some embodiments, a bioreactor is provided. The bioreactor includes a decellularized bone scaffold, an oxygen supply in gaseous communication with the bone scaffold and a vasculature in fluid communication with the bone scaffold. In some embodiments, the bioreactor is adapted to provide a biomimetic microenvironment to the scaffold.
[0020] It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the disclosed subject matter claimed.
[0021] The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the disclosed subject matter. Together with the description, the drawings serve to explain the principles of the disclosed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] A detailed description of various aspects, features, and embodiments of the subject matter described herein is provided with reference to the accompanying drawings, which are briefly described below. The drawings are illustrative and are not necessarily drawn to scale, with some components and features being exaggerated for clarity. The drawings illustrate various aspects and features of the present subject matter and may illustrate one or more embodiment(s) or example(s) of the present subject matter in whole or in part.
[0023] FIGS. 1A-C illustrate tissue-engineered models of Ewing's sarcoma (TE-ES) according to embodiments of the present disclosure.
[0024] FIGS. 2A-C illustrates characterization of TE-ES models according to embodiments of the present disclosure.
[0025] FIGS. 3A-D illustrate expression of hypoxic and glycolytic tumor phenotypes according to embodiments of the present disclosure.
[0026] FIGS. 4A-D illustrate angiogenesis and vasculogenic mimicry according to embodiments of the present disclosure.
[0027] FIG. 5 illustrates re-expression of tumor genes in a 3D tissue-engineered model of Ewing's sarcoma according to embodiments of the present disclosure.
[0028] FIGS. 6A-F illustrate generation and characterization of TE-bone according to embodiments of the present disclosure.
[0029] FIGS. 7A-D illustrate characterization of Ewing's sarcoma cell lines according to embodiments of the present disclosure.
[0030] FIG. 8 illustrates focal adhesion genes and cancer genes expressed in Ewing's sarcoma tumors and bone but not in cell lines according to embodiments of the present disclosure.
[0031] FIG. 9 illustrates focal adhesion genes differentially expressed in Ewing's sarcoma tumors and tumor cell lines according to embodiments of the present disclosure.
[0032] FIG. 10 illustrates cancer related genes differentially expressed in Ewing's sarcoma tumors and tumor cell lines according to embodiments of the present disclosure.
[0033] FIG. 11 illustrates focal adhesion and cancer genes differentially expressed in Ewing's sarcoma tumors and cell lines according to embodiments of the present disclosure.
[0034] FIGS. 12A-C illustrates an NPK mouse model according to embodiments of the present disclosure.
[0035] FIG. 13 illustrates the differences between mouse prostate tumors and human bone mets according to embodiments of the present disclosure.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0036] Reference will now be made in detail to exemplary embodiments of the disclosed subject matter, an example of which is illustrated in the accompanying drawings. Methods and corresponding steps of the disclosed subject matter will be described in conjunction with the detailed description of the system.
[0037] Overview
[0038] Cell Culture. Human Ewing's sarcoma SK-N-MC and RD-ES cell lines were purchased from American Type Culture Collection (ATCC) and cultured according to the manufacturer's specifications. Ewing's sarcoma tumors were obtained from Columbia University Tissue bank. Human Mesenchymal Stem Cell (hMSC) cultivation, seeding and osteogenic differentiation, were performed.
[0039] Pellets formation: To form pellets, 0.3×10 6 Ewing's sarcoma cells were centrifuged in 15 mL Falcon tubes with 4 mL of medium and cultured at 37° C. with 5% humidified CO 2 for one week. Tissue engineered model of tumor. Scaffolds (4 mm diameter×4 mm high cylinder) were prepared from fully decellularized bone, seeded with 1.5×10 6 hMSCs (passage 3) and incubated in 6 mL of osteogenic medium for 4 weeks. Medium was changed biweekly. After 4 weeks, the scaffolds were bisected; one half was seeded with Ewing's sarcoma cells (3 pellets per scaffold) and the other half was used as a control.
[0040] Microarray data analysis. Expression of genes in Ewing's Sarcoma and cell lines was studied in 11 cell lines and 11 tumors by applying the barcode method. A probe set was considered expressed in cell lines/tumors only if detected in all cell lines/tumors. Where a gene had multiple probe sets, the gene was only counted once. Genes expressed in cell lines, but not tumors, or in tumors, but not cell lines, were identified from the asymmetric difference of both sets.
[0041] Quantitative real-time PCR (qRT-PCR). Total RNA was obtained using Trizol (Life Technologies) following the manufacturer's instructions. RNA preparations(2 μg) were treated with “Ready-to-go you-prime first-strand beads” (GE Healthcare) to generate cDNA. Quantitative real-time PCR was performed using DNA Master SYBR Green I mix (Applied Biosystems). mRNA expression levels were quantified applying the ΔCt method, ΔCt=(Ct of gene of interest—Ct of GAPDH). Histology and Immunohistochemistry (IHC). Ewing's sarcoma models were fixed in 10% formalin, embedded in paraffin, sectioned into 4 μm slices and stained with haematoxylin and eosin (H/E). Engineered models and tumor samples were stained for CD99, osteopontin (OPN), bone sialoprotein (BSP), and osteocalcin (OCN).
[0042] With regard to FIG. 5 , re-expression of tumor genes in a 3D tissue-engineerted model of Ewing's sarcoma is depicted. Analysis of Osteopontin (OPN), Bone Sialoprotein (BSP), and Osteocalcin (OCN) in Ewing's sarcoma cell lines cultured in 2D, native tumor samples and engineered 3D model of Ewing's sarcoma (RD-ES). (A) Analysis by qRT-PCR of the indicated ECM genes in two Ewing's sarcoma cell lines and in hMSC. Values correspond to the average±SD (n=3). (B) Immunostains of Ewing's sarcoma tumor samples. (C) Immunostains of the healthy controls and RD-ES engineered bone samples. Representative sections stained for Hematoxylin/Eosin and for CD99 and ECM proteins are shown.
[0043] RESULTS: By comparing gene expression profiles of clinical tumor samples and Ewing sarcoma cell lines, genes were identified that were expressed in tumors but not in cell lines. Bioinformatics analysis showed 599 genes up-regulated in tumors and not in the cells. By qRT-PCR 33 genes were identified that were implicated in focal adhesion and cancer. The three MEC proteins (OPN, BSP and OSC) were not expressed in tumor cells ( FIG. 5A ), in contrast to the actual Ewing's sarcoma tumor samples that expressed high levels of these proteins ( FIG. 5B ). Notably, when the same tumor cells were cultured within the context of the engineered bone tumor model, they re-expressed all three proteins ( FIG. 5C ).
[0044] In contrast, immortalized Ewing's sarcoma cells cultured in 2D do not express genes implicated in important pathways related to focal adhesion and cancer and expressed at high levels in tumor tissues. An in vitro model of Ewing's sarcoma tumor was constructed by introducing the tumor cells into an engineered bone environment, which showed that the tumor cells re-expressed the silenced genes under these conditions. This Ewing's sarcoma model can serve as a tool for cancer drug discovery and target identification because it provides gene profiles of the tumor cells similar to those in a native tumor.
[0045] Tumor Bone-Engineered Model
[0046] Cell culture and animal models have tremendously advanced our understanding of cancer biology. However both systems have limitations. Herein is described a bioengineered model of human Ewing's sarcoma that mimics the in vivo bone tumor niche with high biological fidelity. In this model, cancer cells that have lost their transcriptional profiles after monolayer culture re-express genes related to focal adhesion and cancer pathways. The bioengineered model recovers the original hypoxic and glycolytic tumor phenotype, and leads to re-expression of angiogenic and vasculogenic mimicry features that favor tumor adaptation. Differentially expressed genes between the monolayer cell culture and tumor environment are potential therapeutic targets that can be explored using the bioengineered tumor model.
[0047] Both the two-dimensional (2D) culture and in vivo models of cancer may be used to unravel the complex mechanisms and molecular pathways of cancer pathogenesis. Cancer cells lose many of their relevant properties in 2D culture, due to the lack of the native-like physiological milieu with 3D extracellular matrix (ECM), the other cells and regulatory factors. As a result, 2D cultures are not predictive of antitumoral drug effects in the human being. Animal models have their own limitations in representing human disease, necessitating the use of clinical data. While simple 3D models of cancer, such as tumor spheroids, cell inserts, and cell encapsulation in hydrogels or porous scaffolds are an advance over monolayer cultures, cancer cells still remain deprived of native tumor environments where cancer cell-nonmalignant cell interactions are crucial for tumor biology. Indeed, the microenvironment can both inhibit and facilitate tumor growth and metastatic dissemination to distant organs. Current approaches are far from replicating the native in vivo milieu in which tumors develop, a necessary condition for advancing cancer research and translating novel therapies into clinical practice.
[0048] The present disclosure describes a model of human bone cancer (such as prostate cancer and Ewing's sarcoma) engineered by introducing tumor cell spheroids into their resident bone tissue environment that has been formed by culturing human mesenchymal stem cells in decellularized bone matrix. This model allows not only the cross-talk between the cancer cells, but also the interactions of cancer cells with the human bone cells and the mineralized bone matrix. Within such native-like environment, cancer cells (i) re-express focal adhesion and cancer related genes that are highly expressed in tumors but lost in monolayer cultures, (ii) recapitulate the original hypoxic and glycolytic tumor phenotypes, and (iii) acquire angiogenic capacity and vasculogenic mimicry that favor tumor initiation and adaptation. Bioengineered models of human bone cancer can be valuable tools for identifying genes that are differentially expressed between cell lines and tumors, and thus representing potential therapeutic targets.
[0049] Tissue-Engineered Model of Ewing's Sarcoma (TE-ES)
[0050] Referring to FIG. 1 , tissue engineered models of Ewing's sarcoma according to embodiments of the present disclosure (TE-ES) are illustrated. FIG. 1A depicts a methodology used to develop bioengineered models of Ewing's sarcoma tumor. FIG. 1B depicts TE-ES generation. Fully decellularized bone scaffolds (4 mm diameter×4 mm high plugs) are seeded with hMSCs. After 4 weeks of culture in osteogenic differentiation medium, bone constructs are bisected. One half is seeded with Ewing's sarcoma spheroids (3 per construct); the other half is used as control (TEbone). Both TE-ES and TE-bone are cultured for 2 or 4 weeks in ES medium. FIG. 1C shows Hematoxylin and Eosin images of TE-bone controls and TE-ES models (TE-RD-ES, TE-SK-N-MC, TE-EW-GFP) at week 2 and 4 after introducing tumor spheroids.
[0051] Tumor Model To form the tumor model according to some embodiments, Ewing's sarcoma (ES) spheroids (providing a 3D context for local interactions of cancer cells) are introduced into a human bone niche generated by tissue-engineering technology (TE-bone) ( FIG. 1A ). TE-bone plugs are cultured for 4 weeks in osteogenic differentiation medium. In parallel, tumor spheroids are cultured in ES medium for one week. TEbone plugs are bisected through the center, and 3 ES spheroids are introduced into one half of the construct, generating the Tissue-engineered Ewing's Sarcoma (TE-ES) model; the other half of each TE-bone plug can serve as control. TE-ES models and their control counterparts are cultured for an additional 2 or 4 weeks in ES medium ( FIG. 1B ). Three different TE-ES models are generated, using various ES cell lines (TE-RD-ES, TE-SK-N-MC, TE-EW-GFP) ( FIG. 1C ).
[0052] Bone Niche hMSCs differentiate into osteoblastic lineage and form viable, functional human bone when cultured on 3D scaffolds made of decellularized bone in osteogenic-differentiation medium. According to an embodiment of the present disclosure, the following approach is used to engineer a bone niche (TE-bone) for the tumor model. First, the osteogenic potential of hMSC is tested after three weeks of monolayer culture in osteogenic medium. Positive Alkaline phosphatase and Von Kossa stainings ( FIG. 6A-B ) and expression of bone markers by qRT-PCR ( FIG. 6C ) demonstrates bone differentiation capacity of hMSCs. In parallel, 1.5×10 6 hMSC (passage 3) are cultured in 4×4mm cylindrical decellularized bone scaffolds for 6 and 8 weeks, in osteogenic differentiation medium, and observed elevated expression levels of bone-related markers (OPN, BSP and OCN) as compared to the differentiation of same cells in monolayer cultures ( FIG. 6D ). Bone-related protein expression by IHC suggest that TE-bone is properly generated ( FIG. 6E ). Hypoxia is a pivotal microenvironmental factor for tumor development. Thus, hypoxia is confirmed in the middle of the TE-bone by tissue immunofluorescence of pimonidazole-binding cells ( FIG. 6F ).
[0053] Ewing's sarcoma cells Ewing's sarcoma family of tumors (ESFT) is characterized by aggressive, undifferentiated, round cells, with strong expression of CD99, affecting mostly children and young adults. ESFT comprises of Ewing's sarcoma (ES) that arises in bone, extraosseous ES (EES), peripheral primitive neuroectodermal tumors (pPNET) and Askin's tumors with a neuroectodermal origin. The chromosomal translocation t(11:22)(q24:q212) is the most common mutation (˜85-90% of cases) in ESFT and leads the formation of the EWS/FLI fusion protein which contributes to tumorigenesis in the cells of origin. Analyses of molecular signatures suggest that ESFT originate from mesenchymal and neural crest.
[0054] Referring to FIG. 2 , characterization of TE-ES models are depicted. In FIG. 2A , Immunohistochemical staining of TE-bone and TE-ES models for Ewing's sarcoma marker CD99 at weeks 2 and 4 are shown. Insets represent negative controls without primary antibody. Representative images are shown (n=3 per condition). Counterstaining is performed with Hematoxylin QS (blue) FIG. 2B depicts qRT-PCR analysis of GFP, EWS-FLI and NKX2.2. FIG. 2C depicts qRT-PCR analysis of the ES genes expressed in tumors and not in cell lines cultured in 2D. In all cases, fold change is calculated by first normalizing to actin levels in the individual samples and then to the corresponding levels in cells cultured in 2D. Data are shown as Average±SD (n=3-5). Two-tailed Student's t-test was used to determine statistical significance. *p<0.05; p<0.01, p<0.001; nd, not determined; ns, not significant; T, Ewing's sarcoma tumors.
[0055] Two Ewing's sarcoma cell lines expressing GFP, RD-ES (primary bone tumor cell line) and SK-N-MC (primary cells originated from an Askin's tumor and metastasizing in the supraorbital area) are used to develop the tumor models ( FIG. 7A ). Surface markers (characterized by FACS) are CD13, CD44 and CD73 negative and CD90, CD105 and CD99 positive ( FIG. 7B ). In order to generate in vitro an ES cell line (EW-GFP cell line), a lentiviral plasmid containing the EWS/FLI mutation is introduced into hMSCs ( FIG. 7C ). Surface proteins expression in EW-GFP cell line (by flow cytometry) is compared to hMSCs, exhibiting high levels of the ES-related marker CD99 and losing CD13, CD44 and CD73 hMSC-specific markers ( FIG. 7D ).
[0056] Re-Expression of Focal Adhesion and Cancer-Related Genes
[0057] In order to validate the TE-ES model, histological sections are analyzed by hematoxylin-eosin staining, detecting large areas with small-round cells that were CD99 positive and surrounded by bone cells and ECM ( FIG. 2A ). GFP levels in TE-ES models and their cell line counterparts cultured in monolayers (by qRT-PCR) confirm expression in both cultures ( FIG. 2B ), demonstrating ES tissue formation and the presence of ES cells in the bone context. EWS-FLI mRNA and the EWSFLI target NKX2.2 are expressed at low levels in ES cell monolayers as compared to native ES tumors from patients ( FIG. 2B ). Notably, both genes are up-regulated in all three TE-ES models, for all three cell lines described herein, showing a clear effect of the microenvironment in regulating ES gene profile ( FIG. 2B ).
[0058] Significant differences exist in gene expression between tumors from patients and cells cultured in monolayers, due to the flat, unnatural plastic environment. The presence or absence of expression of genes in 44 tumors from patients and 11 cell lines were analyzed by applying the barcode method to the Affymetrix Human Genome U1332 Plus 2 gene expression data of Savola et al.
[0059] 599 genes are identified that were expressed in tumors but not in cell lines (Table 1). Comparing mRNA expression between the two cell lines (RD-ES and SK-N-MC) and 3 ES tumors by qRT-PCR, upregulation of 24 genes in ES tumors is confirmed. All these genes are related to focal adhesion and pathways in cancer (Table 2; FIGS. 8, 9, 10 and 11 ). Analysis of these 24 genes in the TE-RD-ES and TE-SK-N-MC models relatively to their monolayer counterparts, confirms strong re-expression (fold change >3) for 12 genes ( FIG. 2C ).
[0060] IGF1 is one of the targets found and validated (12.2±4.11 fold change in TE-RD-ES relative to RD-ES cell monolayers; 35.08±16.84 fold change in TE-SKN-MC relative to SK-N-MC monolayers). IGF signal transduction pathway is thought to play a key role in ESFT development and proliferation. These results support the importance of tumor microenvironment for gene expression and suggest that TE-ES models recapitulate, at least in part, ES gene expression signatures.
[0061] Recapitulation of the Hypoxic and Glycolytic Tumor phenotype
[0062] At early stages of cancer, tumors are avascular masses where oxygen and nutrients delivery are supplied by diffusion and therefore, growing in central areas is compromised. To maintain energy production, tumor cells respond and adapt to the hypoxic environment by increasing the amount of glycolytic enzymes and glucose transporters, such as GLUT1 and GLUT3, via the hypoxia-inducible factor-1 (HIF1α). Studies using tumor spheroids and tumor micro-regions in vivo, show an outer viable tumor (with proliferating cells), an inner hypoxic area (with quiescent adapted viable cells) and a central necrotic core where oxygen and glucose levels are critically low. The tumor model provides a native-like niche that mimics tumor heterogeneity in terms of oxygen and nutrients supply, as demonstrated by hypoxia in the center of the tissue constructs, but not in the outer areas ( FIG. 6F ).
[0063] Referring to FIG. 3 , expression of hypoxic and glycolytic tumor phenotypes are depicted. FIG. 3A shows Necrotic areas in the inner part of TE-ES models identified by Hematoxylin and Eosin staining of TE-RDES, TE-SK-N-MC and TE-EW-GFP at week 2. Representative images are shown (n=3 per condition). FIG. 3B shows HIF1α mRNA levels in TE-ES models. Fold change is calculated by first normalizing to actin levels in the individual samples and then to the corresponding levels in cells cultured in 2D. Data are shown as Average±SD (n=3-5). Statistical significance is determined by the two-tailed Student's t test. *p<0.05; p<0.01, p<0.001; ns, not significant. FIG. 3C TUNEL immunofluorescent staining of TE-ES and TE-bone in the center on the models. Upper panel: representative pictures of TUNEL-stained inner areas. Apoptotic cells stain red; cell nuclei were stained by Hoechst 33342. Lower panel: Quantification of TUNELpositive cells in the inner part of the indicated TE-ES models. FIG. 3D shows Immunohistochemical staining of GLUT-1 in the indicated TE models over time. Counterstain: Hematoxylin QS (blue). Representative images are shown (n=3 per condition).
[0064] In order to evaluate whether TE-ES models recapitulate the initial steps of tumor generation, necrotic areas in the core of the tumor models were analyzed and compared the levels of HIF1α and GLUT1 to those in cell monolayers and TE-bone controls. First, focus on the construct interiors revealed necrotic areas similar to those observed in native tumors ( FIG. 3A ). TUNEL assays after 4 weeks of cultivation revealed higher cell death in the middle of the TE-SK-N-MC tumor model (73±36%) relatively to TE-RD-ES (29±3%) and/or TE-EW-GFP(16±2%) ( FIG. 3B ). These results suggest that RD-ES and EW-GFP cell lines may be better adapted than SK-N-MC cell line to restrictive conditions at the centers of the constructs.
[0065] In response to hypoxia (at week 2), transcription levels of HIF1α were 40 times higher in the TE-RD-ES tumor model relatively to the RD-ES cell monolayers, and 30 times higher relatively to TE-bone. HIF1α expression decreased with time in culture, reaching at week 4 levels similar to those in TE-bone ( FIG. 3C ). Transcriptional expression of HIF1α was not significantly increased by hypoxia in TE-SK-N-MC and TE-EW-GFP models as compared to cell lines ( FIG. 3C ). Also, the SK-N-MC and EW-GFP cell lines express higher levels of HIF1α than the RD-ES line, and the expression levels in the SK-N-MC cells were comparable to those in TE-bone. These data suggest that tumor cells that have low transcriptional levels of HIF1α (RD-ES line) increase expression in order to adapt to hypoxic environment. In contrast, cell lines expressing high levels of HIF1 (SK-N-MC and EW-GFP) seem to be insensitive to hypoxia, at least at the transcriptional levels. HIF1α thus appear to play a protective role in the adaptation of tumor cells to hypoxia.
[0066] To assess the role of hypoxia in the induction of glycolytic response, the levels of GLUT1 protein in TE-bone and TE-ES models were examined. Very high levels of GLUT1 are observed favoring glucose uptake and tumor survival in inner areas where oxygen and medium supply are compromised ( FIG. 3D ). GLUT1 was expressed in necrotic areas in the TE-SK-N-MC model.
[0067] Taken together, these data demonstrate that the RD-ES cells expressing high levels of HIF1α adapt to hypoxia in the TE bone environment by recapitulating some aspects of hypoxic and glycolytic tumor phenotype, and mimicking inner-necrotic and outersurvival signatures. In comparison, the SK-N-MC and EW-GFP cells expressing low levels of HIF1α show less ability to adapt to hypoxic microenvironment.
[0068] Recapitulation of Angiogenic Ability and Vasculogenic Mimicry.
[0069] Referring to FIG. 4 , angiogenesis and vasculogenic mimicry are depicted. FIG. 4A shows VEGFa mRNA levels in TEES models. Fold change is calculated by first normalizing to actin levels in the individual samples and then to the corresponding levels in cells cultured in 2D. Data are shown as Average±SD (n=3-5). Two-tailed Student's t-test is used to determine statistical significance. *p<0.05; p<0.01, p<0.001; ns, not significant. FIG. 4B shows Angiogenesis-related proteins detection in TE-ES culture media. Expression levels of the indicated proteins were assessed by ELISA and compared with expression levels in the TE-bone counterparts. FIG. 4C shows qRT-PCR analysis of vasculogenic mimicry markers. Relative endogenous expression of each gene was normalized to actin and the fold change was obtained normalizing to the levels in corresponding cell lines cultured in 2D. Data are shown as Average±SD (n=3-5). Statistical significance was determined by the two-tailed Student's t test. *p<0.05; p<0.01, p<0.001; ns, not significant. FIG. 4D shows representative images of PAS-stained sections from TE-bone and TE-ES models at week 2 and 4. Representative images are shown (n=3 per condition).
[0070] Tumor cells respond to oxygen and nutrient deprivation by promoting vascularization that maintains tumor growth and survival. Induction of vascular endothelial growth factor (VEGF-a) is an essential feature of tumor angiogenesis that is driven by hypoxia and mediated by HIF1α. To address whether hypoxia modulates angiogenic ability of the tumor, VEGF-a transcriptional levels in TE-ES models were analyze. High induction of VEGF-a in TE-RD-ES were found at week 2 compared to the RD-ES cell line and TE bone ( FIG. 4A ). Notably, levels decreased by week 4, as observed for HIF1-α. In further support of the adaptive advantage of RD-ES cells cultured in TE-bone, VEGF-a mRNA levels were not significant increased in TE-SK-N-MC and TE-EW-GFP tumor models as compared to TE-bone controls ( FIG. 4A ).
[0071] Then, angiogenic proteins secreted by TE-ES tumors are identified. By ELISA analysis of 24-hr supernatants, 56 human angiogenesis-related proteins were analyzed at week 2. Due to the differences in growth of different cell lines, it was not possible to directly compare secretion rates. However, these analyses clearly demonstrated that 8 proteins (Angiopoietin, CXCL16, Endothelin-1, FGF-7, IGFBP1-1, PIGF, TGF-B1 and TIMP4) were highly expressed in TE-RD-ES and TE-EW-GFP tumor models compared to TE-bone (fold change >3) In contrast, none of these proteins was detected in the TE-SK-N-MC tumor model. These results confirm that the SK-N-MC cells failed to induce essential adaptive elements to survive and proliferate in TE-bone ( FIG. 4B ). Interestingly, Endothelin-1 is implicated in ES proliferation and invasion while IGFBP1-1 prolongs the half-life of IGF-1, a well-known target gene of EWS-FLI and TGF-β1. These observations are consistent with previous studies, validating the current system.
[0072] Finally, vasculogenic mimicry (VM) is evaluated in TE-ES models. Native ES is featured by the presence of blood lakes and PAS positive cells expressing endothelium-associated genes. This property is known as VM and is stimulated by hypoxia. Thus, VM can provide functional perfusion channels composed only of tumor cells. The endothelium-associated genes (LAMC2, TFPI1 and EPHA2) were highly expressed in the TE-RD-ES at weeks 2 and 4 ( FIG. 4C ), confirming VM in the TE-RDES model.
[0073] Consistent with all other data, cells in the SK-N-MC model re-expressed VM genes as levels lower than those measured for the TE-RD-ES model. However, these expression levels were significantly upregulated at week 2 for TFP1 (p<0.01) and EPHA2 (p<0.05) and at week 4 for LAMC2 (p<0.01) and EPHA2 (p<0.05) as compared to SK-N-MC and TE-bone ( FIG. 4C ). Moreover, the TE-EW-GFP model expressed high levels of LAMC2, TFPI1 and EPHA2 at week 2 and 4 as compared to TE-bone ( FIG. 4C ). Tissue sections stained with PAS revealed positive areas in all the TE-ES models (except in TE-EW-GFP at week 2), as compared to negative-PAS TEbone ( FIG. 4D ). Taken together, these results confirm that RD-ES cell line has higher capability to adapt to TE-bone than the SK-N-MC line.
[0074] According to various embodiments of the present disclosure, human tumor models predictive of native tumors in vitro are provided. Spheroids of tumor cells and porous scaffolds capture 3D aspects with control of oxygen, tension, and pH. Cancer is a complex disease where interactions between tumor cells and non-neoplastic cells play an important role in carcinogenesis. Herein, various embodiments provide models of human tumors, by incorporating Ewing's sarcoma cell spheroids into a bioengineered tridimensional bone niche, and thus enabling multiple interactions of tumor cells with other tumor cells, bone tissue matrix and bone cells.
[0075] Tumor cell lines cultured in 2D lose their transcriptional profiles and downregulate many genes implicated in cell-cell and cell-ECM interactions, such as focal adhesion genes. Gene expression profiles of cell lines cultured in monolayers are compared with native tumors, with focus on differentially expressed focal adhesion genes and cancer pathways. The induction of 12 genes in both TE-RD-ES and TE-SK-N-MC models evidence a major role of microenvironment in the acquirement of tumor expression profile. Models according to the present disclosure can thus be used for characterization of differentially expressed genes and help identify new tumor targets. As discussed above, induction of CDC42 and PPP1R12A is observed, both of which are related to Rho family of GTPases. Inhibition of some Rho pathway members through therapeutic compounds is applied in preclinical studies suggesting that CDC42 and PPP1R12A are potential candidates for ES therapy.
[0076] The bone niche has an important role in acquiring ESFT features to tumor cells, such as hypoxic and glycolytic phenotypes, angiogenesis potential and vasculogenic mimicry. The three ES cell lines discussed herein exhibit different behaviors in the bioengineered tumor model of the present disclosure. The primary bone tumor RD-ES cell line mimics ESFT signature, the in vitro-generated EWS-GFP cell line only in part and the metastatic SK-N-MC cell line was not able to recapitulate many of the tumor characteristics. These differences correlate to the expression levels of HIF1α (low in RD-ES cells, and high in SK-N-MC and EW-GFP cells), suggesting that HIF1α plays a protective role in the adaptation of tumor cells to hypoxia.
[0077] According to various embodiments of the present disclosure, tumor cells are studied within the 3D niche engineered to mimic the native host tissue. In various embodiments, the inclusion of stromal cells is provided, and tumor microvasculature and fine-tuned control of oxygen and nutrients are provided through the use of perfusion bioreactors.
EXAMPLES
[0078] Native Tumors
[0079] Ewing's sarcoma tumors were obtained from a Tissue Bank. The samples were fully de-identified. Three different frozen tissue samples were cut in sets of 6 contiguous 10 μm-thick sections and homogenized in Trizol (Life technologies) for RNA extraction and subsequent gene expression analysis.
[0080] Cell Culture
[0081] Ewing's sarcoma cell lines SK-N-MC (HTB-10) and RD-ES (HTB-166) were purchased and cultured according to the manufacturer's specifications. RD-ES cells were cultured in ATCC-formulated RPMI-1640 Medium (RPMI) and SK-N-MC cells were cultured in ATCC-formulated Eagle's Minimum Essential Medium (EMEM). Both media were supplemented with 10% (v/v) Hyclone FBS and 1% penicillin/streptomycin. EWS-GFP cells were cultured in DMEM supplemented with 10% (v/v) Hyclone FBS and 1% penicillin/streptomycin).
[0082] U2OS osteosarcoma cell line and HEK293T cell line were provided and cultured in Dulbecco's Modified Eagle Medium (DMEM) supplemented with 10% (v/v) Hyclone FBS and 1% penicillin/streptomycin).
[0083] The cultivation, seeding and osteogenic differentiation of Human Mesenchymal Stem Cells (hMSC) were performed. Briefly, hMSC were cultured in basic medium (DMEM supplemented with 10% (v/v) Hyclone FBS and 1% penicillin/streptomycin) for maintenance and expansion, followed by osteogenic medium (basic medium supplemented with 1 μM dexamethasone, 10 mM β-glycerophosphate, 50 μM ascorbic acid-2-phosphate) for osteogenic differentiation. Due to the highly osteogenic properties of the mineralized bone scaffolds used to culture the cells, the supplementation of MBP-2 was not necessary.
[0084] All cells were cultured at 37° C. in a humidified incubator at 5% CO 2 .
[0085] Retroviral and Lentiviral Transductions
[0086] Retroviral transductions were performed using a GFP retroviral vector (pBabe-Puro-GFP). Lentiviral transductions were performed. EWS-FLI-GFP expression vector was provided.
[0087] Tumor Cell Spheroids
[0088] To form tumor cell spheroids, 0.3×10 6 Ewing's sarcoma cells were centrifuged in 15 mL Falcon tubes, 5 minutes at 1200 rpm, with 4 mL of medium and cultured for one week at 37° C. in a humidified incubator at 5% CO 2 .
[0089] Tissue engineered model of tumor Cell culture scaffolds (4 mm diameter×4 mm high plugs) were prepared from fully decellularized bone. The scaffolds were seeded with 1.5×10 6 hMSCs (passage 3) and cultured in 6 mL of osteogenic medium for 4 weeks. Medium was changed biweekly. After 4 weeks, the scaffolds were bisected; one half was seeded with Ewing's sarcoma cells (3 spheroids per scaffold) (TE-ES) and the other half was used as a control (TE-bone).
[0090] Three tumor models were formed using the three tumor cell lines. For each tumor, TE bone was used as a control. TE-RD model (and their counterpart TE-bone controls) were cultured in RPMI medium. TE-SK-N-MC model (and their counterpart TE-bone controls) were cultured in EMEM. TE-EWS-GFP model (and their counterpart TE-bone controls) were cultured in DMEM.
[0091] All culture media were supplemented with 10% (v/v) Hyclone FBS and 1% penicillin/streptomycin. TE-ES and TE-bone models were cultured at 37° C. in a humidified incubator at 5% CO 2 for 2 and 4 weeks.
[0092] Cytometry
[0093] Surface markers analysis by FACS was carried out. hMSC and ES cell lines (RD-ES, SK-N-MC and EWS-GFP) were harvested, centrifugated and incubated at 4° C. for 1 h with fluorochrome conjugated antibodies APC Mouse anti-human CD13 (BD Pharmingen, 557454), APC Mouse anti-human CD44 (BD Pharmingen, 560532), APC Mouse anti-human CD73 (BD Pharmingen, 560847), APC Mouse anti-human CD90 (BD Pharmingen, 559869) and APC Mouse anti-human CD105 (BD Pharmingen, 562408). Negative control cells were stained with APC mouse IgG1, k isotype control, Clone MOPC-21 (BD Pharmingen, 555751). CD99 expression was assed incubating cells with CD99 primary antibody (Signet antibodies, SIG-3620). FACS data were analyzed using FlowJo software version 7.6 (Tree Star Inc., Ashland, Oreg., USA)
[0094] Quantitative Real-Time PCR (qRT-PCR).
[0095] Total RNA was obtained using Trizol (Life Technologies) following the manufacturer's instructions. RNA preparations (2 μg) were treated with “Ready-to-go you-prime first strand beads” (GE Healthcare) to generate cDNA. Quantitative real-time PCR was performed using DNA Master SYBR Green I mix (Applied Biosystems). mRNA expression levels were quantified applying the ΔCt method, ΔCt=(Ct of gene of interest—Ct of Actin).
[0096] GFP primers were selected. Other qRT-PCR primer sequences were obtained from the PrimerBank data base (http://pga.mgh.harvard.edu/primerbank/):
[0000]
Gene Description
PrimerBank ID
beta actin (Actin)
4501885a1
EWS-FLI1 fusion isoform type 8 (EWS-FLI)
633772a1
Homo sapiens NK2 homeobox 2 (NKX2-2)
32307133b1
Homo sapiens tumor protein p53 (TP53)
371502118c1
ACTN4 Homo sapiens actinin, a 4 (ACTN4)
316660986c2
CCND2 Homo sapiens cyclin D2 (CCND2)
209969683c1
COL1A2 Homo sapiens collagen, type I, α2 (COL1A2)
48762933c3
COL3A1 Homo sapiens collagen, type III, α1
110224482c2
(COL3A1)
Homo sapiens collagen, type VI, a1 (COL6A1)
87196338c2
COL6A2 Homo sapiens collagen, type VI, α2
115527065c1
(COL6A2)
COL6A3 Homo sapiens collagen, type VI, α3
240255534c1
(COL6A3)
FLNB Homo sapiens filamin B, β (FLNB)
256222414c2
MYLK Homo sapiens myosin light chain kinase (MYLK
116008189c1
Homo sapiens 3-phosphoinositide dependent protein
60498971c1
kinase-1 (PDPK1)
Homo sapiens protein phosphatase 1, regulatory
219842213c1
subunit 12A (PPP1R12A)
Homo sapiens insulin-like growth factor 1
163659898c1
(somatomedin C) (IGF1)
VCL Homo sapiens vinculin (VCL)
50593538c1
CDKN1B Homo sapiens cyclin-dependent kinase
207113192c3
inhibitor 1B (p27, Kip1) (CDKN1B)
Homo sapiens C-terminal binding protein 1 (CTBP1)
61743966c2
CTBP2 Homo sapiens C-terminal binding protein 2
145580576c1
(CTBP2)
ETS1 Homo sapiens v-ets erythroblastosis virus
219689117c1
E26 oncogene homolog 1 (avian) (ETS1)
c-K-ras2 protein isoform a (KRAS)
15718763a1
PIAS1 Homo sapiens protein inhibitor of activated
7706636c2
STAT, 1 (PIAS1)
Homo sapiens retinoid X receptor, alpha (RXRA)
207028087c3
Homo sapiens signal transducer and activator of
47080104c1
transcription 3 (STAT3)
Homo sapiens cell division cycle 42 (GTP binding
89903014c1
protein, 25 kDa) (CDC42)
Homo sapiens collagen, type IV, α2 (COL4A2)
116256353c1
Homo sapiens catenin (cadherin-associated
148233337c2
protein), β1, 88 kDa (CTNNB1)
Homo sapiens jun proto-oncogene (JUN)
44890066c1
laminin a 4 chain (LAMA4)
4504949a2
Homo sapiens laminin, β 1 (LAMB1)
167614503c1
Homo sapiens laminin, γ1 (formerly LAMB2) (LAMC1)
145309325c3
Homo sapiens phosphoinositide-3-kinase, regulatory
335057530c3
subunit 1 (a) (PIK3R1)
Homo sapiens phosphatase and tensin homolog (PTEN)
110224474c2
Homo sapiens hypoxia inducible factor 1, α subunit
194473734c1
(HIF1A)
Homo sapiens vascular endothelial growth factor A
NM_001101
(VEGFA)
Homo sapiens EPH receptor A2 (EPHA2)
296010835c1
Homo sapiens tissue factor pathway inhibitor (TFPI)
98991770c1
Homo sapiens laminin, γ2 (LAMC2)
157419139c1
[0097] Microarray data analysis. Expression of genes in native Ewing's Sarcoma tumors and cell lines was studied in 11 cell lines and 44 tumors by applying the barcode method to the Affymetrix Human Genome U1332 Plus 2 gene expression data. A probeset was considered expressed in cell lines/tumors only if detected in all cell lines/tumors. Where a gene had multiple probesets, the gene was only counted once. Genes expressed in cell lines, but not tumors, or in tumors, but not cell lines, were identified from the asymmetric difference of both sets.
[0098] Histology and Immunohistochemistry (IHC).
[0099] TE-ES and TE-bone models were fixed in 10% formalin, embedded in paraffin, sectioned at 4 μm and stained with hematoxylin and eosin (H/E). The sections were then stained for CD99 (dilution 1:500; Signet antibodies, SIG-3620) and GLUT1 (dilution 1:500; Abcam, ab652) as previously described, and counterstained with Hematoxylin QS (Vector Labs). For PAS staining, periodic acid-Schiff (PAS) (from Sigma-Aldrich) was used according to the manufacturer's instructions.
[0100] hMSC (passage 3) were plated in 24 well plates (1×10 4 cells/cm 2 ) and cultured for 3 weeks in either basic medium or osteogenic medium. At weeks 1, 2 and 3 osteogenic differentiation was analyzed by alkaline phosphatase activity (Sigma-Aldrich, St Louis, Mo., USA), following the manufacturer's instructions and by von Kossa staining Sections were incubated with 1% AgNO3 solution in water and exposed to a 60 W light for 1 h.
[0101] Hypoxyprobe™-1 (pimonidazole) Kit for the Detection of Tissue Hypoxia (Chemicon International, Inc., Temecula, Calif., USA) was used to detect hypoxia in TE-bone according to the manufacturer's instructions. Preparations were mounted with vectashield and Nuclei were counterstained with DAPI (Vector Labs, H-1200).
[0102] TUNEL assay. Apoptotic cells were detected by an in situ cell death detection kit, TMR red (Roche Applied Science, Mannheim, Germany), according to the manufacturer's instructions. The assay measures DNA fragmentation by immunofluorescence using TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling) method at the single cell level. One hundred cells per field (n=3) in the center of the TEES model (n=3) were counted to quantify the percentage of apoptotic cells. Nuclei were stained with Hoechst 33342 (Molecular probes).
[0103] Enzyme-Linked Immunoabsorbent Assay (ELISA)
[0104] 24-hour supernatants from TE-ES and TE-bone controls were analyzed to detect angiogenic proteins, using a Proteome Profiler Human Angiogenesis Array Kit (R&D Systems, ARY007) according to the manufacturer's instructions.
[0105] With regard to FIG. 6 , generation and characterization of TE-bone is illustrated. In FIG. 6A Osteogenic differentiation evidenced by Alkaline phosphatase staining hMSCs in monolayer were cultured in hMSC medium or osteogenic medium for 3 weeks. Alkaline phosphatase staining was performed at week 1, 2 and 3 as described in supplementary methods. Differentiated stem cells positive for alkaline phosphatase were stained blue. Images are representative of n=3 samples per condition. FIG. 6B shows Mineral deposition analysis by the von Kossa method. hMSC were cultured as specified in FIG. 6A . Black stained phosphate deposits demonstrated osteogenic differentiation of hMSC. Images are representative of n=3 samples per condition. FIG. 6C shows qRT-PCR analysis of bone genes during osteogenic differentiation in monolayer. mRNA levels of Osteopontin (OPN), Bone Sialoprotein (BSP), and Osteocalcin (OCN) in hMSC cultured in monolayer in hMSC medium or osteogenic differentiation medium were assessed to demonstrate osteogenic induction and bone differentiation. Data are shown as Average+SD (n=3) FIG. 6D shows qRT-PCR analysis of bone genes during osteogenic differentiation in scaffold. mRNA levels of Osteopontin (OPN), Bone Sialoprotein (BSP), and Osteocalcin (OCN) in hMSC cultured in a bone scaffold for 6 and 8 weeks in osteogenic differentiation medium were assessed and compared to hMSC at t=0.
[0106] FIG. 6E shows Bone-related protein expression analysis by IHC in TE-bone at week 8. Counterstaining was performed with hematoxylin QS (blue). Representative images are shown (n=3); H/E, Hematoxylin and Eosin. FIG. 6F shows Hypoxia analysis of TE-bone by tissue immunofluorescence of pimonidazole-binding cells (green). Nuclei were stained with DAPI. Representative images are shown (n=3 per condition).
[0107] Referring to FIG. 7 , charactarization of Ewing's sarcoma cell lines is illustrated. FIG. 7A shows Morphology of the ES cell lines RD-ES and SK-N-MC. Left panel: brightfield images showing typical small round cell morphology. Right panel: GFP expression images by fluorescence microscopy. RD-ES and SK-N-MC were stably transduced with pBabe-GFP retroviral vector as described in supplementary methods. FIG. 7B shows FACS analysis of negative and positive surface markers in Ewing's sarcoma cells. FIG. 7C shows Top panels: brightfield images of hMSC (passage 3) and transduced with EWS-GFP vector at day 30 (without passage) and day 35 (passage 2). Low panels: GFP expression images at day 30 and 35 post-transduction. FIG. 7D shows Analysis of hMSC and ES surface markers in EW-GFP cell line. hMSC were CD13, CD44, CD90 and CD105 positive and expressed low levels of the ES-specific CD99 marker. EWS-GFP at day 35 lost hMSC surface proteins, acquiring ES surface markers and expressing high levels of CD99.
[0108] Tables 1 and 2 illustrate genes differentially expressed in Ewing's sarcoma tumors and cell lines. Table 1: Number of genes expressed in ESFT and in cell lines. Table 2: Focal adhesion genes and related to pathways in cancer genes expressed in ESFT but not in cell lines.
[0000]
TABLE 1
Condition
Number of genes
Genes expressed in cell-lines
2977
Genes expressed in tumors
2430
Genes expressed in cell-lines but not tumors
1312
Genes expressed in tumors not cell-lines
599
[0000]
TABLE 2
Focal adhesion:
ACTN4, CCND2, COL1A2, COL3A1, COL6A1,
COL6A2, COL6A3, FLNB, MYLK, PDPK1,
PPP1R12A, IGF1, VCL
Pathways in
CDKN1B, CTBP1, CTBP2, ETS1, KRAS, PIAS1,
cancer:
RXRA, STAT3, TP53
Both:
CDC42, COL4A1, COL4A2, CTNNB1, FN1, JUN,
LAMA4, LAMB1, LAMBC1, PIK3R1, PTEN
[0109] Referring to FIG. 8 , focal adhesion genes and cancer genes expressed in Ewing's sarcoma tumors and bone but not in cell lines are illustrated. qRT-PCR data are shown for two Ewing's sarcoma cell lines (RD-ES and SK-N-MC), three Ewing sarcoma tumors (ESFT) and one osteosarcoma cell line unrelated to ESFT, as control of bone tumor cell line. Relative endogenous expression of each gene was normalized to actin (Average±SD, n=3).
[0110] Referring to FIG. 9 , focal adhesion genes differentially expressed in Ewing sarcoma tumors and cell lines are illustrated. qRT-PCR analysis of focal adhesion genes expressed in Ewing sarcoma tumorsESFT but not in cell lines. Data are shown for two Ewing's sarcoma cell lines (RD-ES and SK-N-MC), three Ewing sarcoma tumors (ESFT) and one osteosarcoma cell line as control of bone tumor cell line but unrelated to ESFT. Relative endogenous expression of each gene was normalized to actin (Average±SD, n=3).
[0111] Referring to FIG. 10 , cancer related genes differentially expressed in Ewing sarcoma tumors and cell lines are illustrated. qRT-PCR analysis of cancer related genes expressed in Ewing sarcoma tumors (ESFT) but not in cell lines. Data are shown for two Ewing's sarcoma cell lines (RD-ES and SK-N-MC), three tumors (ESFT) and one osteosarcoma cell line unrelated to ESFT as control of bone tumor cell line. Relative endogenous expression of each gene was normalized to actin (Average±SD, n=3).
[0112] Referring to FIG. 11 , focal adhesion and Cancer related genes differentially expressed in Ewing sarcoma tumors and cell lines are illustrated. qRT-PCR analysis of cancer related genes expressed in ESFT but not in cell lines. Data are shown for two Ewing's sarcoma cell lines (RD-ES and SK-N-MC), three tumors (ESFT) and one osteosarcoma cell line unrelated to ESFT as control of bone tumor cell line. Relative endogenous expression of each gene was normalized to actin (Average±SD, n=3).
[0113] Bioengineered Metastatic Tumors Using Mouse Models of Prostate Cancer
[0114] The predominant site of human prostate cancer metastasis is bone. Bone metastasis is the most frequent cause of death from prostate cancer. Genetically engineered mouse (GEM) models enable studies of metastasis in the native physiological milieu, and are suitable to model progression from tumorigenesis to metastasis. However, GEM models only rarely metastasize to bone, and fail to recapitulate the heterogeneity of human cancer phenotypes. In fact, a GEM model of fully penetrant metastatic prostate cancer displays metastases to many soft tissue sites but rarely if ever to bone. However, cells derived from this mouse model (i.e., NPK cells) readily form tumors when injected into the tibia.
[0115] The present disclosure combines generating mouse models of prostate cancer with tissue-engineering techniques, to evaluate prostate cancer metastasis in human bone context. The early metastasis tumor model can be evaluated by comparing to colonization of human or mouse prostate cancer cells injected through blood circulation into host mice that have been grafted with human or mouse bone. The advanced metastasis model can be evaluated by comparing to tumors formed by injecting human or mouse cancer cell aggregates directly into the grafted human or mouse bone. The host mice for these analyses can be non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice engrafted with human bone.
[0116] A series of GEM models are provided that display a range of prostate cancer phenotypes and share conserved molecular pathways deregulated in human prostate cancer and particularly activation of PI3-kinase and MAP kinase signaling pathways. In particular, while NP (Nkx3.1 CreERT2/+; Ptenflox/flox) tumors do not metastasize, NPK (Nkx3.1CreERT2/+; Ptenflox/flox; KrasLSL-G12D/+) tumors metastasize with nearly 100% penetrance to lymph nodes and soft tissues, most frequently to lungs and liver ( FIGS. 12A-B ), but not into the mouse bone. However, when implanted directly into the bone of host mice, the bone is rapidly colonized by the mouse tumor cells ( FIG. 13D ).
[0117] Lineage-tracing experiments using a Cre reporter allele R26R-YFP that indelibly marks prostate tumor cells, shows prominent YFP fluorescence in prostate tumors, lungs and livers from NPK mice that display metastases, but not in lungs or livers from NP mice that do not display metastases ( FIG. 12B ). Lineage-tracing is used to delineate the temporal and spatial relationship of tumors, disseminated cells, and metastases in the NPK mice, to observe a clear temporal delay in the appearance of metastasis which appear at 2-3 months relative to primary tumors which appear after only 1 month ( FIG. 13C ).
[0118] Metastasis Assay for Prostate Cancer Using the Bone-Engineered System
[0119] By using both human (PC3—highly metastatic and 22Rv1—non-metastatic) and mouse (NP-non metastatic, NPK-highly metastatic) prostate cancer cells, prostate cancer metastasis can be studied in a tissue- and species-specific manner, to determine whether the mouse bone provides the permissive microenvironment for prostate cancer metastasis as does human bone. These studies can be performed with both human and mouse prostate cancer cells. It is distinguishable whether preferential homing of human prostate cancer to bone (which cannot be readily recapitulated in mouse models) reflects a property of the primary tumor cells (human versus mouse) or whether tumor cells have a selective preference for human bone regardless of whether they are derived from mice or man.
[0120] To follow the cells in vivo the human PC3 and 22Rv1 cells are transduced with retroviral particles to stably express a dual luciferase-RFP reporter using a pMXs-IRES-Luc-RFP retroviral vector (Abate-Shen lab). Mouse NP and NPK cells are derived from mice already carrying a lineage tracing allele based on the expression of the YFP protein under the control of the R26r promoter. These cells are transduced to stably express a luciferase reporter by removing the RFP cassette. First, human pre-vascularized engineered bone (4×4 mm discs) is generated by sequential culture of hMSCs and HUVECs in bone scaffolds. After 4 weeks, engineered bone is implanted subcutaneously in male NOG/SCID mice for 10 days, a period that is sufficient to allow bone vascularization. Ten days post-implantation, 2.5×105 PC3 or NPK cells are injected into the tail vein with the luciferase-marked human or mouse prostate cancer cells, as above, and the mice are monitored twice a week for tumor formation in distant organs including the bone, using a Xenogen IVIS imaging system 15 minutes after intraperitoneal injection of 1.5 mg D-Luciferin. This model is compared to an early metastasis model. In separate animals, not implanted with human bone, human PC3 and mouse NPK cells transduced with luciferase reporter will be injected (105 cells per mouse) directly into the mouse tibia ( FIG. 13C ), to be compared with the advanced metastasis model. Second, 105 cells are implanted orthotopically into the mouse prostate and monitored over a period of 3 months for dissemination to distant organs, and into the implanted engineered bones (human and mouse). This assay provides the most stringent conditions for recapitulating almost entirely the initial steps of local invasion and extravasation.
[0121] While the disclosed subject matter is described herein in terms of certain exemplary embodiments, those skilled in the art will recognize that various modifications and improvements may be made to the disclosed subject matter without departing from the scope thereof. Moreover, although individual features of one embodiment of the disclosed subject matter may be discussed herein or shown in the drawings of the one embodiment and not in other embodiments, it should be apparent that individual features of one embodiment may be combined with one or more features of another embodiment or features from a plurality of embodiments.
[0122] In addition to the specific embodiments claimed below, the disclosed subject matter is also directed to other embodiments having any other possible combination of the dependent features claimed below and those disclosed above. As such, the particular features presented in the dependent claims and disclosed above can be combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter should be recognized as also specifically directed to other embodiments having any other possible combinations. Thus, the foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed.
[0123] It will be apparent to those skilled in the art that various modifications and variations can be made in the method and system of the disclosed subject matter without departing from the spirit or scope of the disclosed subject matter. Thus, it is intended that the disclosed subject matter include modifications and variations that are within the scope of the appended claims and their equivalents. | A 3D decellularized bone scaffold seeded with cancer cells, such as prostate cancer cells or Ewing's sarcoma is provided. It provides platform technology for controllable, quantitative, long-term studies of tissue-engineered tumors, including prostate cancer and Ewing's sarcoma. The scaffold can be used with cancer cell lines to identify therapeutic targets to slow, stop, and reverse tumor growth and progression as well as to predict the efficacy of potential therapeutics. | 2 |
FIELD OF THE INVENTION
[0001] The invention relates to methods and apparatus for reading information from a 3D optical storage medium.
BACKGROUND OF THE INVENTION
[0002] It has been suggested in the art, to store information in three dimensional optical storage apparatuses. One of the problems to be solved in such systems is how to read information from a particular point without letting the reading light beam being distracted by the storage medium positioned between the reading light source and the said particular point.
[0003] WO 01/73779 co-owned by the owner of the present invention, suggests reading the information by two-photon absorption. In this method, the information stored in a particular point is characterized by the absorption coefficient in a certain frequency v, and the reading is carried out with two light beams having frequencies v 1 and v 2 , so that v 1 +v 2 =v (v 1 −v 2 =v is also possible). Only when the two light beams intersect, the light may be absorbed and reading takes place. In all the points where the two beams do not intersect, there is no light of frequency v, and therefore no reading. The storage medium should be transparent to light having a frequency v 1 , and also to light having the frequency v 2 .
[0004] Regarding the storage means, it is suggested in WO 01/73779 to use a matrix carrying stilbene derivatives, having one characteristic absorption in a given frequency when in the cis isomer and another, when in the trans.
[0005] In optical storage media such as optical disks in general and DVDs in particular, data is stored along tracks formed in the bulk of the optical disk and is read by focusing a laser beam produced by semiconductor diodes on to the tracks, while spinning the disk on its axis. The tracks generally comprise spiral tracks on which data is written and from which the data is read.
[0006] Obviously in order to retrieve data correctly it is essential that the reading head can locate and follow a desired track. In practice this leads to two different kinds of tracking problem: skipping from one track to another and faithfully following a single track. For the purpose of the present discussion, it suffices to observe that these two different tracking problems require different solutions and to the extent that the method of tracking is relevant to the present invention, the present invention is concerned only with the second of the two problems.
[0007] U.S. Pat. No. 5,592,462 (Beldock) issued Jan. 7, 1997 entitled ‘“Three-dimensional optical data storage and retrieval” discloses a three dimensional optical data storage and retrieval system having a three dimensional optical data storage medium and an apparatus for providing access to data stored on the medium. In accordance with one aspect, the data storage medium includes a number of concentric shells each of which has a curvilinear data storage surface for storing data in a number of substantially parallel data tracks. According to another aspect, the data storage medium includes a number of data storage surfaces, which are rotatable about a common axis, each data storage surface for storing data in a number of substantially circular data tracks and having an optically transparent window, which transects each of the data tracks. In use, each shell or data storage surface is rotated about a common axis and tracking is achieved by directing the reading beam through the optically transparent windows on to a data track of interest. Thus, this reference is not applicable to retrieving data from a solid optical storage medium wherein the data is stored in multiple layers.
[0008] The manner in which CD and DVD reading head track a destination track is based on focusing the reading spot on to the track and measuring the intensity of a reflected spot by position sensitive detectors. This allows calculation of the position of the reading spot and subsequent adjustment of the reading head's location based on the measured error.
[0009] US 20010040844 published Nov. 15, 2001 (Sato et al.) entitled “Tracking servo apparatus of optical information recording and reproducing apparatus” discloses a tracking servo apparatus using this technique. Thus, reflection light obtained when a laser beam is irradiated onto a recording surface of an optical disc is photoelectrically converted, thereby obtaining a photoelectric conversion signal. A tracking error signal showing an amount of deviation of an irradiating position of the laser beam for a track in a disc radial direction on the recording surface is generated by the photoelectric conversion signal. A spherical aberration occurring in an optical system is detected, a level of lie tracking error signal is corrected on the basis of the detection result, and the irradiating position of the laser beam is moved in the disc radial direction in accordance with the level-corrected tracking error signal.
[0010] Likewise, U.S. Pat. No. 6,233,210 published May 15, 2001 (Schell; David L.) entitled “Optical drive error tracking method and apparatus” discloses a method and apparatus for obtaining a tracking error signal for an optical disk player which is general across the various data formats found in CD audio disks and DVDs. A photodetector having at least four active areas is used to sense the reflected laser beam. A differential amplitude tracking error signal is generated by comparing the signal strength in the different active areas.
[0011] These references are typical of known solutions for maintaining the read/write head in communication with a desired track using a photodetector having multiple sections that serves as a position-sensitive detector for detecting a component of the read/write laser beam reflected from the surface of the optical disk.
[0012] For both CDs and DVDs, axial compensation translates to a focusing adjustnent of the read/write beam.
SUMMARY OF THE INVENTION
[0013] It is an object of the invention to provide a method and system for retrieving information from a three dimensional storage medium.
[0014] It is a further object of the invention to correct tracking errors in such a method and system where the read spot may drift in two essentially orthogonal directions.
[0015] In accordance with a broad aspect of the invention, there is provided a method for retrieving information from a three dimensional storage medium, the method comprising:
[0016] using a three dimensional storage medium comprising an active medium capable of being in two states, wherein a data unit is represented by the ratio between the concentration of the first and second of said two states in a given volume portion of said medium and a data sequence is represented by a sequence of such data units;
[0017] irradiating said active medium with light as to concentrate light flux through a volume portion of said storage medium so as to generate in said volume portion a detectable non-linear optical response characteristic of said concentration ratio;
[0018] detecting said non-linear optical response to retrieve information stored in said volume portion; and
[0019] tracking a data sequence for retrieving said data sequence in a reproducible manner.
[0020] Within the context of the description and appended claims, the term “data unit” refers to a bit or symbol of a finite alphabet. Preferably, the data sequence is tracked via a tracking feedback signal for positioning the light at a predetermined volume portion of the storage medium.
[0021] According to a further aspect of the invention there is provided a method for correcting tracking errors in an optical storage medium having multiple tracks arranged in different layers of the optical storage medium, the tracking comprising:
[0022] (a) directing a reading spot that is nominally focused on to a track in the optical storage medium,
[0023] (b) continually moving the reading spot in axial and radial directions,
[0024] (c) receiving a signal having an amplitude which varies according to respective offsets from the track in radial and axial directions,
[0025] (d) using the received signal to determine a direction of a respective offset from the track in radial and axial directions, and
[0026] (e) adjusting a location of the reading spot accordingly.
[0027] Any active medium known in the art is suitable for use according to the present invention. Some non-limiting examples to active media are those described in WO 01/73779 and in U.S. Pat. No. 5,268,862, both of which are incorporated herein by reference, stillbene derivatives, and azobenzene derivatives.
[0028] The active medium is preferably embedded in a supporting matrix, for instance, as a dopant or, when the supporting matrix is a polymer, as a monomer co-polymerized with the supporting matrix. The supportive matrix should be transparent for the light irradiated on it by the method of the invention and to the light generated by the non-linear optical process. Non-limiting examples of supportive matrices suitable for use according to the present invention are polyethylene, polypropylene, polycarbonate, and polymethylmetacrilate (PMMA).
[0029] Typically, the data is stored in a binary mode, so that the concentration ratio representing one digit is 1:0 and the concentration ratio representing the other digit is 0:1. Here, 1 and 0 are not absolute values but rather should be interpreted as the highest and lowest concentrations that may be achieved during the writing process, which is not discussed herein.
[0030] As an alternative to storing the data in binary mode, other schemes may be devised where the there are more than two states of the media (e.g. completely in isomerics states A or B, in the thermal equilibrium or close to it, in one of a multitude of photo stationary states and more). The size of the alphabet used in the encoding-decoding process depends on the encoding-decoding method used and on the signal separation and the signal resolution (signal to noise ratio) of the system. Many encoding-decoding methods are known in the art, DC free and run length limited encoding-decoding are non-limiting examples of such families of codes.
[0031] The size of the volume portion from which a data unit is retrieved according to the invention is the size of the light spot wherein the flux is large enough to generate a detectable non-linear reaction. Generally, smaller spot sizes may compensate for weaker light intensities. Therefore, working with spots having a radius of less than 30 μm is advisable, and spots having a radius equal to or smaller than the wavelength of the irradiated light is preferable.
[0032] Small spots allow the use of cheaper light sources. However, it may be beneficial to work at high intensity of a given light source, even if a non-linear response is detected at lower intensities. This is so because above some intensity, due to saturation effects, the response is no longer sensitive to the intensity, and the reading is also not sensitive thereto. This way noise may be reduced from the measurement.
[0033] Detection of the signal requires its separation from other light signals that may exist in the environment. Such separation may be achieved by any method known for this purpose in the art, such as directing the non-linearly generated signal into a direction where it is the only source for light of its frequency by satisfying phase matching conditions; filtering the light through a filter, prism, grating, polarizers, etc.; using phase sensitive detection, lock-in amplifier, a box-cars, and/or gated averaging method. All the available methods may be applied whether the beams irradiating the active medium are collinear or not.
[0034] Non-linear optical processes are very sensitive to the flux of light. As the flux varies as a function of volume element when a beam of light is focused through matter, a dramatic increment in the effective efficiency occurs when approaching the focal point. The effective result of this is that with the appropriate photon flux, the process occurs only at the locus of maximal power, that is the focal point. When using a single light source at a single wavelength, this focal point is straightforwardly defined as the location where the beam waist is minimal.
[0035] When using more than one wavelength the most efficient way to achieve the same effect of high localization is by overlapping the focal point of all photon sources involved in the relevant process. When different foci are not exactly overlapping, the same process occurs, albeit less efficiently, in the volume generated by the crossing of the effective volume elements generated by the foci of all light sources. To gain additional effective efficiency in a one-wavelength process higher fluxes can be achieved through the use of more than one light source using the same methods as for the multi-wavelength case.
[0036] The superposition principle allows one to consider a single beam as a plurality of beams whose respective foci are trivially located in the same location. Therefore within the context of the present invention and the appended claims where reference is made to two or more intersecting light beams, it is to be understood that a single light beam may give rise to a non-linear process analogous to the overlapping of two or more monochromatic beams, and this is encompassed by reference in the claims to the intersection of two or more light beams.
[0037] One family of non-linear optical responses suitable for use according to the present invention is a multi-photon fluorescence, such as, but not limited to, two-photon fluorescence.
[0038] Non-limiting examples of non-linear optical responses related to a χ (n>2) process, are four wave mixing processes such as Stimulated Raman Scattering, Coherent Anti-Stokes Raman Scattering (CARS), Raman induced Kerr effect, and degenerate four-wave mixing. Similar χ (5) processes and higher are also known in the art and may be used according to the present invention.
[0039] According to another aspect of the present invention there is provided an apparatus for retrieving information from a three dimensional storage medium by generating a non-linear optical response of said storage medium, detecting said nonlinear optical response and analyzing and processing it. Such an apparatus includes, in order to generate and detect a non-linear optical response, at least one light source, which in some cases (such as CARS) must be coherent; a detector for detecting light, which is different in at least one characteristic from the light provided by said light sources. In this context, examples of light characteristics are the light wavelength, polarization, and propagation direction. And means for tracking, i.e. process the signals received from the medium to get a tracking feedback signal and correct the location of the read spot accordingly. The apparatus may also include means, known per se in the art for analyzing and processing detected signals and retrieving information therefrom. These may comprise means for digitizing the detected signal, such as an A/D converter, and an algorithmic error detection means, such as error detector code running on a computer or on an electronic chip.
[0040] A light source according to the present invention may be an active light source like a laser, or a passive light source like a mirror. A beam splitter, for example, may be considered as two (passive) light sources.
[0041] According to one embodiment of the invention the data sequences are arranged as layers within the medium, each layer consisting of a spiral track of the respective data sequences, where the medium is shaped as a disk, and rotated around its axis by the apparatus. The purpose of the invention is to track the spiral track corresponding to a required data sequence in r and z coordinates when the disk rotates. It is assumed that the track suffers limited amount of run-out both in r (radial run-out) and z (axial run-out) coordinates. Such distortions can occur in the event that the axis of rotation is slightly off the disk center and slightly non-parallel to the disk plane normal, such that the data spiral moves relative to the reading spot while the disk rotates. The invention enables tracking the data spirals by calculating a tracking error signal that is used as feedback for the servo-mechanisms that control the r and z position.
[0042] The basic tracking principle is to perpetually move (modulate) the reading spot in a periodical path around its nominal current position (traveling the r-z plane by two orthogonal functions of time). This modulation causes a modulation in amplitude and phase of the read signal that depends on the position of the reading spot relative to the data spiral. This dependence is used to determine the tracking error.
[0043] As a simplified example of the way the tracking algorithm calculates an error signal, consider a 2-D case. Assume the z coordinate is fixed such that the lasers spot is focused at the proper height and there is no axial run-out. As the reading spot propagates along the track, the spot's radial position is modulated in the radial direction so that the spot is half the time in (towards the center of the disk) and half the time out relative to the track (i.e. r<r o half of the time and r>r o half of the time). It should be noted that the offset relative to track center has to be small to ensure that signal is still detected with a signal to noise ratio that is high enough for other functions such as symbol detection or synchronization to be accomplished. If the signal has a fixed average and the tracking is perfect, than the average of the ‘in’ signal (signal detected when spot is ‘in’ relative to the track) is equal to the ‘out’ signal. If the spot's position begins to diverge from the track's position e.g. because of eccentricity of the disk, the expansion of the spiral or some other reason, then the difference between the ‘in’ and ‘out’ parts of the modulated signal, out-in, is negative if there were a small ‘run-out’ or positive if there was ‘run-in’.
[0044] Two main factors determine the frequency of the modulation. It should be high enough to be able to respond to fast changes of the relative location of the track and the spot, but low enough to average enough data units so that the signal will be independent of the stored data. The averaging of the data can be accomplished by window integration or other appropriate low pass techniques. To ensure that in each integration window the signal is data-independent, DC free encoding techniques are used.
[0045] In another embodiment of the tracking mechanism the error signal calculation is accomplished by multiplying (inner product) the time variation of the data envelope (the read signal) with the reading spot modulation function. In this scheme the error signal is weighted by the strength of the modulation, i.e. signal measured when the amplitude of the modulation is high contribute more to the error signal. Further refinement of the invention is to include delay compensation before the multiplication between the signal and the modulation.
[0046] The tracking errors are used as feedback signals for the servo machine controlling the nominal spot position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] In order to understand the invention and to see how it may be carried out in practice, specific embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:
[0048] FIG. 1 is a graph showing CARS spectra of solid solutions having two different concentration ratios between cis and trans isomers of a given compound;
[0049] FIG. 2 is a schematic illustration of an apparatus according to the present invention;
[0050] FIG. 3 is a block diagram showing functionally a read/write system for use with the invention;
[0051] FIGS. 4 a and 4 b are pictorial representations showing the effect of sinusoidally modulating the position of the reading head in the system of FIG. 2 ; and
[0052] FIGS. 5 and 6 are block diagrams showing details of a tracking system for use with the system shown in FIG. 2 .
DETAILED DESCRIPTION OF INVENTION
[0053] A solid solution of 10% cis-4,4′-dimethoxy-α,α-diciano stillbene (hereinafter compound A) in PMMA was irradiated with collinear laser beams of 844 and 1037 mn that were focused through a lens to a spot smaller than 10 μm. CARS signal at a wavelength of 711 mn was detected. The spectra of the signal detected from a solid solution of the cis isomer and of a cis-trans mixture is given in FIG. 1 .
[0054] FIG. 2 is an illustration of an apparatus 100 according to the present invention for retrieving information from a three dimensional storage medium (hereinafter referred to as “disk”) 102 having an information carrying volume (not shown). The apparatus 100 includes two lasers 104 and 106 , each being a source for a beam of coherent light ( 110 and 112 respectively), and a detector 120 for detecting a beam of coherent light 116 which is of different wavelength to the light provided by the lasers 104 and 106 . The detector 120 transfers an electric signal, created therein due to the detection of an optical signal produced by the beam of coherent light 116 , to a low noise amplifier 123 , which can be a lock in amplifier to a tracking unit 125 , so that the data sequence may be faithfully followed, and to an A/D converter 126 , whose output is fed to a decoder and error detection and correction (ECC) unit 128 (constituting an algorithmic error detector), so that information encoded in the data sequence may be retrieved.
[0055] In the embodiment shown in FIG. 2 there is also a disk mount 202 for mounting thereon the disk 102 , so that the disk, when mounted, may be rotated around its center by a motor 205 . The two light sources 104 and 106 are connected to two optical fibers 104 ′ and 106 ′ arranged to direct the light signals 110 and 112 to a dichroic mirror, 220 . The signal 112 is transferred through the mirror and the signal 110 is reflected thereby. Thus, the light may irradiate the disk 102 , in such a maimer that the beams common focus 222 is located within the information carrying volume of the disk 102 .
[0056] The optical unit 101 is mounted on an arm 210 , which may rotate around an arm axis 230 . A lens 240 , of the kind used in CD players, is positioned between the dichroic mirror 220 and the disk 102 . Its position in the direction parallel to the disk's surface 102 ′ is controlled by the combination of the rotations of the arm 210 around the arm axis 230 and the disk 102 around the disk mount 202 . Its position in the direction perpendicular to the disk's surface 102 ′ is controlled by a magnetic coil 242 , which is also used to control small radial motions of the lens and thus the position of the common focus 222 within the disk 102 may be fully controlled. To achieve tracking, the location of the common focus is modulated by moving the lens 240 by applying a periodical electric signal to the magnetic coil 242 . The coherent light sources 110 and 112 in combination with the dichroic mirror 220 , the lens 240 and the magnetic coil 242 constitute an optical system 245 . A collecting mirror 250 is positioned to collect the non-linearly generated signal 116 and directs it to the detector 120 , positioned near the arm axis 230 , through a filter 152 . The laser drivers are not shown in FIG. 2 .
[0057] The large ratios between the radius of the motion of the optical unit 101 around its axis 230 and track radius on the one hand and the size of the spot and the distance between adjacent tracks and layers on the other hand allow the approximation that the motion controlled by the rotation of the optical unit 101 around its axis is essentially orthogonal to the track of the data sequence.
[0058] To track, the system is provided with a tracking servo system shown generally as 125 , which feeds a correction signal to the magnetic coil 242 for moving the lens 240 under control of the tracking error signal to nominally position the beam spots at the center of the track so that the tracking error signal is zero. Coarse motion of spot is achieved by motion of the optical unit as a whole. Fine motion is achieved by the motion of the lens using the magnetic coil 242 .
[0059] Although the tracking system 125 shown in FIG. 2 serves to track the data sequence recorded on the specific disk 102 as described above, it is to be noted that the invention encompasses a novel tracking system, which is well-suited for use in the apparatus 100 described above with reference to FIG. 2 although it is also suitable for use in other optical data retrieval systems. Likewise, it is to be noted that other tracking systems may be employed in the apparatus 100 .
[0060] The improved tracking system according to the invention is described below with particular reference to FIGS. 4 a , 4 b and 5 of the drawings. However, by way of general introduction there will first be described functionally with reference to FIG. 3 a read/write system 300 for a 3-D optical storage medium 102 having a tracking system. To the extent that the read/write system 300 includes components that are common to the apparatus 100 shown in FIG. 2 , identical reference numerals will be employed.
[0061] The read/write system 300 comprises a rotary shaft 302 driven by an appropriate driving motor 205 for rotating the optical storage medium 102 set thereon, and an optical unit 101 for reading information from one of the tracks in the optical storage medium 102 .
[0062] The optical unit 101 comprises semiconductor lasers 104 and 106 for radiating a pair of intersecting light beams having a volume of intersection that forms a “spot”. Also included within the optical unit 101 is an optical system 245 for creating a focused spot whose location is controlled by an actuator 306 , which in the particular embodiment shown in FIG. 2 is constituted by the magnetic coil 242 . The optical unit 101 is driven by a motor 307 so as to produce the required coarse and fine motion of spot described above.
[0063] The system further comprises a laser driving circuit 308 for energizing the semiconductor lasers 104 , and 106 to emit the respective laser beams.
[0064] In order to retrieve information from a desired track on the optical storage medium 102 , the optical focus 222 must be kept on the desired track. To this end, the system is provided with a tracking servo system shown generally as 125 , which feeds a correction signal to the lens actuator 306 for moving the optical system 245 under control of the tracking error signal to nominally position the beam spots at the center of the track so that the tracking error signal is zero.
[0065] FIGS. 4 a and 4 b shows pictorially the effect of sinusoidally modulating the position of the optical focus 222 in the system of FIGS. 2 and 3 . So far as the reading spot is concerned it tracks data written into a continuous linear data track 321 while being subjected to spatial modulation that shifts its position continually from one side of the track to the other. Although the data is stored in tracks, the invention relies on the principle that even if the optical focus 222 is slightly off-center, data signal will still be read, albeit at reduced intensity. Thus, the further off-center the optical focus 222 is moved, the lower will be the magnitude of the data signal.
[0066] Thus, with reference to FIG. 4 a , consider the case where the tracking is perfect and the reading spot is symmetrical with respect to the data track 321 , its position being shown by the sinusoidal curve 322 . In this case, the average signal will be equal on both sides of the data track 321 . However, in the case of imperfect tracking as shown in FIG. 4 b , the reading spot is asymmetrical with respect to the data track 321 , its actual line of symmetry being depicted by a dotted center-line 323 , shown to right of the data track 321 . The signal is inversely proportional, in perhaps a non-linear fashion, to the distance of the sinusoidal curve 322 from the data track 321 . Thus, in FIG. 4 b where the sinusoidal curve 322 is offset to the right of the data track, this results in a lower signal from samples made when the sinusoidal curve 322 is to the right of the center line 323 , thus indicating the spot is offset to the right of the data track 321 and must therefore be shifted to the left in order to correct the off-set.
[0067] The tracking operates on the principle that by continually reading the data and, at the same, continually modulating the position of the reading head, the resulting moving average signal intensity that is read may be used to indicate to which side, both axially and radially, the reading head is located. This having been determined, the reading head may then be moved in an opposite direction until it is found to be disposed symmetrically relative to the track in both axial and radial directions.
[0068] FIGS. 5 and 6 are block diagrams showing functionally details of a tracking system 125 that is described in polar coordinates (r, θ, z) defining a position of the beams' intersection in the optical recording medium. The tracking system behaves substantially identically for both radial and axial tracking. A modulator 332 spatially modulates the location of the optical focus 222 by a (r, z) modulation signal and feeds the resulting modulated data signal to the optical storage medium 102 . The modulation signal itself is fed together with the measured data signal to an error determination unit 333 , whose output is an error signal that is fed back to the optical unit 101 to correct the axial and radial offsets thereof. The modulator 332 in conjunction with the error determination unit 333 constitutes a tracking error correction unit. A rotation unit 334 provides a continuous change of θ.
[0069] FIG. 6 shows in simplified form the principal functionality of the error determination unit 333 comprising a first 2-input multiplier 340 to whose first input the (r, z) modulation signal is fed and to whose second input is fed the data signal read by optical unit 101 at the position (r, θ, z) in the optical storage medium 102 . An output of the multiplier 340 is fed to a window integrator 341 which integrates the product of the data signal with the modulation signal so as to generate at its output a composite (r, z) error signal in the radial and axial directions.
[0070] As described above by way of example with reference to FIGS. 4 a and 4 b of the drawings, the modulation signal can be a sinusoidal function of the form m=(sin (ωt), cos (ωt)) t . The output of the window integrator may then be represented by:
err ( t ) = ∫ t - T t m I ( t ) ⅆ t
[0071] The intensity I(t) is inversely proportional in a non linear fashion to the distance from the center of the track. Thus, when the head is above the center of the track the modulation intensity is strongest, and it decays to zero when the head moves far from it. “T” represents the length of the time window of the integrator during which the modulated intensity is averaged. “T” should not be so large that it impacts negatively on the reaction time and creates distortions; but neither should it be too low since it is very difficult to construct a mechanical scanning system.
[0072] However, the modulation signal can be any suitable cyclic function which serves to move the optical focus 222 on either side, in both axial and radial directions, of the reading spot. Thus, it can be a square wave function or any other suitable cycle function. It is assumed that the frequency of the modulation signal is much lower than the frequency at which data is read. The window integrator 341 thus operates as a low pass filter.
[0073] The tracking operates on the principle that by continually reading the data and, at the same, continually modulating the position of the reading head, the resulting moving average signal intensity that is read may be used to indicate to which side, both axially and radially, the reading head is located. This having been determined, the optical focus may then be moved in an opposite direction until it is found to be disposed symmetrically relative to the track in both axial and radial directions.
[0074] Whilst the tracking method has been described with particular regard to a tracking system for use with a 3-D optical storage retrieval system wherein data is stored at voxels written in the bulk of the material, it will be understood that the principles of the invention are equally applicable to other kinds of optical storage media where data is stored as a quasi-linear data sequence.
[0075] The embodiment illustrated in FIG. 2 is only one of many embodiments available to the artisan when designing an apparatus according to the present invention. Some non-limiting examples for variations from this embodiment include: the lens and the mirror may be replaced by any other optical means which is known to bring to the same result, the optical fibers may be omitted or replaced by any other wave-guide, the combination of a disk mount and an arm axis may be replaced by any other means for controlling the location of the common focus in the plains parallel to the disk's surface 102 ′, etc.
[0076] It should also be noted that although the preferred embodiment is directed to retrieval of data, the tracking system according to the invention is equally suitable for use when writing data to the optical medium. | A method and apparatus for retrieving information from a three dimensional storage medium uses a three dimensional storage medium having an active medium capable of exhibiting first and second states, a data unit being represented by the ratio between the concentration of the first and second states in a given volume portion of the medium and a data sequence is represented by a sequence of data units. The active medium is irradiated with light as to concentrate light flux through a volume portion of the storage medium so as to generate in the volume portion a detectable non-linear optical response characteristic of the concentration ratio, which is detected and used for tracking. | 6 |
FIELD OF THE INVENTION
[0001] The invention relates to a vibration isolation member and more particularly the invention relates to a vibration isolation member that provides substantially equal dynamic stiffness in radial and axial directions and comprises an outer member with an inner periphery, an inner member with an outer periphery and a resilient member joining the inner and outer members wherein the dimensions of the inner and outer peripheries provide for an interference therebetween in the event of a failure of the elastomer.
BACKGROUND OF THE INVENTION
[0002] Vibration isolation members are frequently used in aircraft interior applications to reduce the vibration and noise exposure to delicate and sensitive instrumentation and also to passengers in the aircraft cabin. In aircraft applications the vibration isolation members must provide the requisite vibration reduction with a minimum size and weight vibration isolation member.
[0003] One means for effectively reducing such exposure to noise and vibration is to use a vibration isolation member that has iso-elastic stiffness properties. A vibration member that is iso-elastic has equal stiffness in the axial and radial directions. Iso-elastic stiffness permits the vibration isolator to provide dependable performance in any orientation and maximize vibration reduction for a given installation. A vibration isolation member that does not provide such iso-elastic stiffness properties will transmit vibration more efficiently in one or more directions, compared to an iso-elastic vibration member having the same minimum stiffness.
[0004] Additionally, it is desirable to include a mount fail-safe feature that prevents the mount from separating in the event the mount fails under loading. Several prior art mounts provide fail safe features that function in a single axial direction however, such prior art mounts typically do not have two fail safe paths. Moreover, in vibration isolation members that comprise iso-elastic members, the members frequently do not have a fail-safe or interference path that is defined by the components that comprise the mount. Rather the fail-safe feature is produced by adding washers or other discrete mechanical members to the member. The additional components required to provide a fail safe feature in an iso-elastic vibration isolation member add weight and increase the volume required to house the member in the aircraft.
[0005] The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide a vibration isolator that provides iso-elastic stiffness in combination with fail safe feature and thereby solves one or more of the shortcomings of present isolation devices and methods. Accordingly, a suitable vibration isolation member is provided including features more fully disclosed hereinafter.
SUMMARY OF THE INVENTION
[0006] In one aspect of the present invention this is accomplished by providing a vibration isolation member that provides iso-elastic stiffness and at least one fail-safe feature.
[0007] More specifically the vibration isolation member of the present invention comprises an inner member comprising an outer periphery having a first dimension; an outer member comprising a base and a shroud that extends away from the base, the shroud adapted to overlay the inner member, said shroud defining an inner periphery having a second dimension, the second dimension being less than the first dimension; and a resilient member constrained between the shroud and the inner member, whereby the vibration isolation member provides iso-elastic stiffness and an interference between the inner and outer members in the event of a failure of the resilient member.
[0008] The inner member is unitary and is comprised of a stem and a seat where the seat includes a first surface, a second surface spaced from the first surface and a third surface that joins the first and second surfaces. The third surface is oriented at an angle relative to the first surface. The seat has a frustoconical configuration.
[0009] The outer member shroud may comprise a single segment or may comprise a first segment, a second segment and a third segment, the second segment joining the first and third segments. The outer member first segment is oriented substantially axially, the third segment is oriented substantially radially and the second segment is oriented at an angle relative to the first and second segments. The third surface of the seat is substantially parallel to the second segment of the shroud.
[0010] The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] [0011]FIG. 1 is an isometric view of the vibration isolation member of the present invention.
[0012] [0012]FIG. 2 is a top view of the vibration isolation member of FIG. 1.
[0013] [0013]FIG. 3 is a longitudinal sectional view taken along line 3 - 3 of FIG. 2.
[0014] [0014]FIG. 4 is a longitudinal sectional view like the sectional view of FIG. 3 illustrating a second embodiment vibration isolation member of the present invention.
[0015] [0015]FIG. 5 is a longitudinal sectional view like the sectional view of FIG. 3 illustrating third embodiment vibration isolation member of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] Turning to the drawing Figures wherein like parts are referred to by the same numbers in the Figures, the first embodiment vibration isolation member 10 of the present invention is disclosed in FIGS. 1, 2 and 3 .
[0017] Generally, vibration isolation member 10 comprises an inner member 12 , an outer member 14 and a resilient member 16 that joins the inner and outer members. The resilient member is constrained between the inner and outer members. The inner and outer members 12 and 14 are relatively rigid. The vibration isolation member 10 is made from a conventional molding process well known to those skilled in the art and during the molding process the resilient member is bonded to the inner and outer members. The resilient member 16 may be comprised of any suitable material however for purposes of the preferred embodiment of the invention the resilient member is comprised of a silicone or a synthetic rubber.
[0018] As shown in the sectional view of FIG. 3, the isolator is adapted to be connected between a support structure 18 such as an aircraft frame for example, and a suspended body 20 which may be an interior aircraft instrument or trim panel. The isolator 10 of the present invention reduces the transmission of vibratory disturbances, which may be in the form of acoustic noise, between the support structure 18 and the suspended body 20 . The isolator also limits heat transfer between body 20 and structure 18 . Also shown in FIG. 3, the isolation member is joined to the suspended body 20 by conventional fastener 22 that extends between the body 20 and inner member 12 ; and is joined to the support structure 18 by fasteners 24 a , 24 b that extend through the outer member 14 . The fasteners may be comprised of any suitable fastener well known to those skilled in the art including, but not limited to screws or quick-connect fasteners. By these connections, the outer member 14 remains substantially stationary during use and the inner member 12 may be displaced in radial and axial directions represented by respective directional arrows 25 and 26 .
[0019] The relatively rigid inner member 12 is unitary and comprises an axially extending cylindrical stem 30 and frustoconical seat 32 . As shown in FIG. 3, the seat includes first and second faces 34 and 36 joined by angled surface 38 that extends outwardly from face 34 to face 36 . The surface 38 may extend at any suitable angle, Θ relative to face 34 . For purposes of describing the preferred embodiment of the invention, the angle may be about 55°. The stem is made integral with the seat 32 at face 34 and the free end of the stem extends outwardly from the opening in the outer member 14 defined by inner periphery 62 . Faces 34 and 36 are circular, planar members that join the surface 38 at respective outer edges. The inner member includes an axially extending bore 40 that extends through the stem and seat and is adapted to receive fastener 22 previously described above. The seat defines an outer periphery 42 that comprises a diameter, D′. The extent of the inner member outer periphery 42 is also represented in dashed font in FIG. 2. As shown in FIG. 3, when the member 10 is installed the seat is located proximate the support member 18 . Additionally, as shown in FIG. 3, the surface 36 is located a distance away from the support structure 18 to allow for displacement of inner member 12 when the isolation member 10 experiences a vibratory disturbance.
[0020] The relatively rigid outer member 14 is unitary and comprises a substantially planar flange or base 50 with bores 52 a and 52 b that are adapted to receive fasteners 24 a and 24 b as described hereinabove. The base 50 is made integral with an annular shroud 54 that overlays seat 32 . The shroud comprises a first segment 56 that extends in the axial direction defined by arrow 26 , a second segment 58 that extends substantially parallel to surface 38 , and a third segment 60 that extends in the radial direction defined by arrow 25 . The second segment 58 joins the first and third segments 56 and 60 . See FIG. 3. Although the second segment is shown at an orientation that is substantially parallel to surface 38 it should be understood that although such a parallel configuration is preferred the second segment could be oriented at any relative angle and do not have to be parallel.
[0021] Third segment 60 terminates at inner periphery 62 that defines diameter, D″. As shown in FIGS. 2 and 3, the outer periphery 42 has a diameter D′ that has a greater radial dimension than inner periphery 62 diameter, D″. In the event that resilient section fails, and the seat is displaced axially toward panel 20 , an interference or fail-safe load path would be created between the seat and the segment 60 preventing further displacement of seat outward from the outer member. Thus the inner member would be captured by the outer member. As shown most clearly in the sectional view of FIG. 3, to ensure that the desired interference is produced between the seat and shroud, the inner periphery 62 must terminate radially inwardly from the outer periphery 42 .
[0022] During molding, resilient member 16 is bonded to the surface 38 and also to the inner surface of second segment 58 . Additionally, the molding process produces relatively thin skin segments bonded along the inner surface of third segment 60 and inner periphery 62 , stem 30 and surface 34 , outer periphery 42 and along portions of the inner surfaces of flange 50 and first segment 56 . Apart from the skins, the main portion of the resilient member 16 has a substantially trapezoidal cross section.
[0023] The vibration isolation member 10 of the present invention provides iso-elastic stiffness. The term “iso-elastic” means that the isolation member 10 has substantially the same stiffness in the axial and radial directions for any applied load. Because the resilient member 16 is constrained between the inner member 12 and outer member 14 the resilient member 16 experiences combined shear loads and loads in either tension or compression regardless of the direction and magnitude of the load applied to the vibration isolation member 10 .
[0024] The vibration isolation member 10 of the present invention provides a double fail safe feature that captures the inner member and maintains it in the chamber 80 defined by the outer member and the support structure 18 . Failure of the elastomer member 16 or failure of the bonds between member 16 and either inner member 12 or outer member 14 will not permit the inner member to relocate outside of the outer member. The inner member is captured by either the structural panel 18 or by the interference between the seat and segment 60 as described hereinabove. Therefore, in order for the inner member seat to become displaced from the chamber 80 , failure of the inner member, outer member fasteners or structural member must occur in addition to the resilient member failure. Additionally, in the event the resilient member 16 fails the seat will not be displaced out of chamber 80 . The suspended body 20 will engage the rigid outer member while the seat will interfere with the inner member. Additionally, the structural member will impede additional axial displacement of the seat towards member 20 . In this way, the mount of the present invention provides double fail-safe feature in combination with its iso-elastic stiffness.
[0025] A second preferred embodiment vibration isolation member 70 is shown in FIG. 4. The alternate embodiment mount 70 includes relatively rigid inner member 72 comprises stem 30 and seat 32 which defines angled surface 38 . The stem 30 , seat 32 and surface 38 as well as the other components and features are the same as those described hereinabove in conjunction with first embodiment vibration isolation member 10 . In the second embodiment mount 70 , the stem 30 and seat 32 may be made directly integral. The inner member 72 does not include surface 34 joining the stem and seat. The second embodiment member 70 includes the double fail-safe feature and also includes an iso-elastic stiffness.
[0026] A third preferred embodiment vibration isolation member 75 is illustrated in FIG. 5. The alternate embodiment mount 75 includes relatively rigid outer member 76 with shroud 78 . As shown in FIG. 5, the shroud member is comprised of a hollow cone with a wall comprised of a single angled segment, that terminates at an inner periphery 62 . As described in conjunction with first embodiment isolation member 10 , the inner periphery 62 has a diameter D″ that is less than the diameter D′ of the outer periphery 42 of the seat 32 . The other components and features of member 75 are the same as those described hereinabove in conjunction with first embodiment vibration isolation member 10 . The third embodiment member 70 includes the double fail-safe feature and also includes an isoelastic stiffness.
[0027] It should be understood the use of outer member 76 and inner member 72 are not limited to the isolation members shown in their respective embodiments but rather, outer member 76 may be combined with inner member 72 if desired.
[0028] While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims. | A vibration isolation member comprising an inner member comprising an outer periphery having a first dimension; an outer member comprising a base and a shroud that extends away from the base, the shroud adapted to overlay the inner member, said shroud defining an inner periphery having a second dimension, the second dimension being less than the first dimension; and a resilient member constrained between the shroud and the inner member, whereby the vibration isolation member provides iso-elastic dynamic stiffness and an interference between the inner and outer members in the event of a failure of the resilient member. | 5 |
TECHNICAL FIELD
[0001] The present invention relates generally to a nonwoven fabric, and specifically to a durable lightweight nonwoven fabric wipe, comprising improved strength, as well as an improved MD to CD elongation ratio, which results in a material imminently suitable for application in the cleaning and cleansing of surfaces.
BACKGROUND OF THE INVENTION
[0002] The production of conventional textile fabrics is known to be a complex, multi-step process. The production of fabrics from staple fibers begins with the carding process where the fibers are opened and aligned into a feed stock known as sliver. Several strands of sliver are then drawn multiple times on a drawing frames to further align the fibers, blend, improve uniformity as well as reduce the slivers diameter. The drawn sliver is then fed into a roving frame to produce roving by further reducing its diameter as well as imparting a slight false twist. The roving is then fed into the spinning frame where it is spun into yarn. The yarns are next placed onto a winder where they are transferred into larger packages. The yarn is then ready to be used to create a fabric.
[0003] For a woven fabric, the yarns are designated for specific use as warp or fill yarns. The fill yarns (which run on the y-axis and are known as picks) are taken straight to the loom for weaving. The warp yarns (which run on the x-axis and are known as ends) must be further processed. The large packages of yarns are placed onto a warper frame and are wound onto a section beam were they are aligned parallel to each other. The section beam is then fed into a slasher where a size is applied to the yarns to make them stiffer and more abrasion resistant, which is required to withstand the weaving process. The yarns are wound onto a loom beam as they exit the slasher, which is then mounted onto the back of the loom. The warp yarns are threaded through the needles of the loom, which raises and lowers the individual yarns as the filling yarns are interested perpendicular in an interlacing pattern thus weaving the yarns into a fabric. Once the fabric has been woven, it is necessary for it to go through a scouring process to remove the size from the warp yarns before it can be dyed or finished. Currently, commercial high speed looms operate at a speed of 1000 to 1500 picks per minute, where a pick is the insertion of the filling yarn across the entire width of the fabric. Sheeting and bedding fabrics are typically counts of 80×80 to 200×200, being the ends per inch and picks per inch, respectively. The speed of weaving is determined by how quickly the filling yarns are interlaced into the warp yarns, therefore looms creating bedding fabrics are generally capable of production speeds of 5 inches to 18.75 inches per minute.
[0004] In contrast, the production of nonwoven fabrics from staple fibers is known to be more efficient than traditional textile processes as the fabrics are produced directly from the carding process. Nonwoven fabrics are suitable for use in a wide variety of applications where the efficiency with which the fabrics can be manufactured provides a significant economic advantage for these fabrics versus traditional textiles.
[0005] Various cleaning products, and specifically personal or baby wipes, are commercially available which utilize one or more layers of carded nonwoven fabrics within the construct of the wipe. Nonwoven carded webs tend to be lightweight and lacking integrity, exhibiting a poor CD elongation performance. In order to make thicker webs, multiple cards, or transverse folding of the web, also called cross-lapping can be used. As will be recognized by those familiar with the art, a precursor web formed by “100% in-line card” refers to a web formed entirely from carded fibers, wherein all of the fibers are principally oriented in the machine direction of the web. A precursor web formed by “all cross-lap” refers to a fibrous web wherein the fibers or filaments have been formed by cross-lapping a carded web so that the fibers or filaments are oriented at an angle relative to the machine direction of the resultant web. Cross-lapping a carded web enhances the overall strength of the web, as well as decreases web elongation; however cross-lapping a carded web also decreases the process speed of the resulting nonwoven fabric.
[0006] A need remains for a lightweight, yet durable carded wipe material that can be manufactured at faster production speeds, as well as exhibits improved MD to CD strength and elongation ratios.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to a nonwoven fabric, and specifically to a durable lightweight nonwoven fabric wipe, comprising improved strength, as well as an improved MD to CD elongation ratio, which results in a material imminently suitable for application in the cleaning and cleansing of surfaces.
[0008] In accordance with the present invention, a method of making the nonwoven fabric embodying the present invention includes the steps of providing a precursor web comprising a fibrous matrix. The fibrous matrix is composed of a blend of staple length fibers, which are carded and cross-lapped once to form a precursor web. The cross-lapper front apron speed is directly related to the line speed and the number of folds the cross-lapper imparts into the carded web. Manufacturing the lightweight nonwoven fabric wipe by setting the cross-lappers to impart one fold into the web effectively increases the production speed. As a result, a lightweight yet durable nonwoven fabric is able to be produced at a lower cost.
[0009] A method of making the durable, yet lightweight nonwoven fabric wipe further comprises the steps of providing a precursor web, which is subjected to hydroentangling. U.S. Pat. No. 3,485,706, to Evans, hereby incorporated by reference, discloses processes for effecting hydroentanglement of nonwoven fabrics. More recently, hydroentanglement techniques have been developed which impart images or patterns to the entangled fabric by effecting hydroentanglement on three-dimensional image transfer devices. Such three-dimensional image transfer devices are disclosed in U.S. Pat. No. 5,098,764, hereby incorporated by reference, with the use of such image transfer devices being desirable for providing a fabric with enhanced physical properties as well as having a pleasing appearance.
[0010] The precursor web is formed into an imaged and patterned nonwoven fabric by hydroentanglement on a foraminous surface, including, but not limited to a three-dimensional image transfer device, embossed screen, three-dimensionally surfaced belt, or perforated drum. In a preferred embodiment, a three-dimensional transfer device defines three-dimensional elements against which the precursor web is forced during hydroentangling, whereby the fibrous constituents of the web are imaged and patterned by movement into regions between the three-dimensional elements of the transfer device. Further, the precursor web is preferably hydroentangled on a foraminous surface prior to hydroentangling on the image transfer device. This pre-entangling of the precursor web acts to integrate the fibrous components of the web, but does not impart imaging and patterning as can be achieved through the use of the three-dimensional image transfer device or the like.
[0011] Manufacture of a lightweight wipe embodying the principles of the present invention is initiated by providing a batt or layer of fibrous components. The fibrous batt can be comprised of finite-length staple fibers or essentially continuous filaments selected from natural or synthetic composition, of homogeneous or mixed fiber length. Suitable natural fibers include, but are not limited to, cotton, wood pulp and viscose rayon. Synthetic fibers, which may be blended in whole or part, include thermoplastic and thermoset polymers. Thermoplastic polymers suitable for use include polyolefins, polyamides and polyesters. The thermoplastic polymers may be further selected from homopolymers; copolymers, conjugates and other derivatives including those thermoplastic polymers having incorporated melt additives or surface-active agents. Staple lengths are selected in the range of 0.25 inch to 8 inches, the range of 1 to 3 inches being preferred and the fiber denier selected in the range of 1 to 15, the range of 2 to 6 denier being preferred for general applications. The profile of the fiber is not a limitation to the applicability of the present invention.
[0012] Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a diagrammatic view of an apparatus for manufacturing a nonwoven fabric, embodying the principles of the present invention;
DETAILED DESCRIPTION
[0014] While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment of the invention, with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated.
[0015] With reference to FIG. 1 , therein is illustrated an apparatus for practicing the present method for forming a nonwoven fabric. The lightweight nonwoven fabric wipe is formed from a fibrous matrix which typically comprises staple length fibers. The fibrous matrix is preferably carded and cross-lapped to impart a single transverse fold into the precursor web, designated P. Limiting the number of imparted folds to one, allows for a lightweight, yet durable wipe to be produced in an in-line process at increased speeds of at least 150 meters per minute. In a current embodiment, the precursor web comprises 100% cross-lap fibers, that is, all of the fibers of the web have been formed by cross-lapping a carded web so that the fibers are oriented at an angle relative to the machine direction of the resultant web.
[0016] FIG. 1 illustrates a hydroentangling apparatus for forming nonwoven fabrics in accordance with the present invention. The apparatus includes a foraminous forming surface in the form of belt 10 upon which the precursor web P is positioned for pre-entangling by entangling manifold 12 . Pre-entangling of the precursor web, prior to imaging and patterning, is subsequently effected by movement of the web P sequentially over a drum 14 having a foraminous forming surface, with entangling manifold 16 effecting entanglement of the web. Further entanglement of the web is effected on the foraminous forming surface of a drum 18 by entanglement manifold 20 , with the web subsequently passed over successive foraminous drums 20 , for successive entangling treatment by entangling manifolds 24 ′, 24 ′.
[0017] The entangling apparatus of FIG. 1 further includes an imaging and patterning drum 24 comprising a three-dimensional image transfer device for effecting imaging and patterning of the now-entangled precursor web. Optionally, the entangling apparatus may include a CPN belt, perforated drum, or any other foraminous surface in place of the three-dimensional image transfer device. The image transfer device includes a moveable imaging surface which moves relative to a plurality of entangling manifolds 26 which act in cooperation with three-dimensional elements defined by the imaging surface of the image transfer device to effect imaging and patterning of the fabric being formed.
[0018] Subsequent to entanglement, fabric integrity can be further enhanced by the optional application of a binder and/or by thermal stabilization of the entangled fibrous matrix. A binder composition that can be either incorporated as a fusible fiber in the formation of the precursor nonwoven web or as a liquid fiber adhesive applied after imaged fabric formation. The binder material can further improve the durability or otherwise provide enhanced cleaning performance of the resultant imaged nonwoven fabric during use.
[0019] In accordance with the present invention, the lightweight nonwoven wipe has a basis weight equal to or less than 2.0 ounces per square yard with an improved CD to MD ratio. Preferably, the wipe has a CD to MD ratio of 3:1, more preferably 2:1, and most preferably 1.5:1. The wipe may comprise finite-length staple fibers or essentially continuous filaments selected from natural or synthetic composition, of homogeneous or mixed fiber length. Suitable natural fibers include, but are not limited to, cotton, wood pulp and viscose rayon. Synthetic fibers, which may be blended in whole or part, include thermoplastic and thermoset polymers. Thermoplastic polymers suitable for use include polyolefins, polyamides and polyesters. The thermoplastic polymers may be further selected from homopolymers; copolymers, conjugates and other derivatives including those thermoplastic polymers having incorporated melt additives or surface-active agents. Staple lengths are selected in the range of 0.25 inch to 8 inches, the range of 1 to 3 inches being preferred and the fiber denier selected in the range of 1 to 15, the range of 2 to 6 denier being preferred for general applications. The profile of the fiber is not a limitation to the applicability of the present invention.
[0020] In accordance with the present invention, the nonwoven lightweight nonwoven wipe includes the use of various aqueous and non-aqueous compositions. The nonwoven wipe may be used in various personal and home care applications, wherein the end use article may be a dry or wet hand held sheet, such as a wipe, a mitt formation, or a cleaning implement capable of retaining the article.
[0021] Cleansing compositions suitable for such end use applications include those that are described in U.S. Pat. No. 6,103,683 to Romano, et al., U.S. Pat. No. 6,340,663 to Deleo, et al., U.S. Pat. No. 5,108,642 to Aszman, et al., and U.S. Pat. No. 6,534,472 Arvanitidou, et al., all of which are hereby incorporated by reference. Selected cleaning compositions may also include surfactants, such as alkylpolysaccharides, alkyl ethoxylates, alkyl sulfonates, and mixtures thereof; organic solvent, mono- or polycarboxylic acids, odor control agents, such as cyclodextrin, peroxides, such as benzoyl peroxide, hydrogen peroxide, and mixtures thereof, thickening polymers, aqueous solvent systems, suds suppressors, perfumes or fragrances, and detergent adjuvants, such as detergency builder, buffer, preservative, antibacterial agent, colorant, bleaching agents, chelants, enzymes, hydrotropes, and mixtures thereof. The aforementioned compositions preferably comprise from about 50% to about 500%, preferably from about 200% to about 400% by weight of the nonwoven lightweight wipe.
[0022] The lightweight wipe embodying the principles of the present invention is also suitable for personal cleaning or cleansing wipes. Non-limiting examples of such applications include dry or wet facial wipes, body wipes, and baby wipes. Suitable methods for the application of various aqueous and non-aqueous compositions comprise aqueous/alcoholic impregnates, including flood coating, spray coating or metered dosing. Further, more specialized techniques, such as Meyer Rod, floating knife or doctor blade, which are typically used to impregnate cleansing solutions into absorbent sheets, may also be used. The following compositions preferably comprise from about 50% to about 500%, preferably from about 200% to about 400% by weight of the nonwoven lightweight wipe.
[0023] The lightweight wipe may incorporate a functional additive, such as an alpha-hydroxycarboxylic acid, which refers not only the acid form but also salts thereof. Typical cationic counterions to form the salt are the alkali metals, alkaline earth metals, ammonium, C 2 -C 8 trialkanolammonium cation and mixtures thereof. The term “alpha-hydroxycarboxylic acids” include not only hydroxyacids but also alpha-ketoacids and related compounds of polymeric forms of hydroxyacid.
[0024] Amounts of the alpha-hydroxycarboxylic acids may range from about 0.01 to about 20%, preferably from about 0.1 to about 15%, more preferably from about 1 to about 10%, optimally from about 3 to about 8% by weight of the composition which impregnates the substrate. The amount of impregnating composition relative to the substrate may range from about 20:1 to 1:20, preferably from 10:1 to about 1:10 and optimally from about 2:1 to about 1:2 by weight.
[0025] Further, a humectant may be incorporated with the aforementioned alpha-hydroxycarboxylic compositions. Humectants are normally polyols. Representative polyols include glycerin, diglycerin, polyalkylene glycols and more preferably alkylene polyols and their derivatives. Amounts of the polyol may range from about 0.5 to about 95%, preferably from about 1 to about 50%, more preferably from about 1.5 to 20%, optimally from about 3 to about 10% by weight of the impregnating composition.
[0026] A variety of cosmetically acceptable carrier vehicles may be employed although the carrier vehicle normally will be water. Amounts of the carrier vehicle may range from about 0.5 to about 99%, preferably from about 1 to about 80%, more preferably from about 50 to about 70%, optimally from about 65 to 75% by weight of the impregnating composition.
[0027] Preservatives can desirably be incorporated protect against the growth of potentially harmful microorganisms. Suitable traditional preservatives for compositions of this invention are alkyl esters of para-hydroxybenzoic acid. Other preservatives which have more recently come into use include hydantoin derivatives, propionate salts, and a variety of quatenary ammonium compounds. Preservatives are preferably employed in amounts ranging from 0.01% to 2% by weight of the composition.
[0028] The cosmetic composition may further include herbal extracts. Illustrative extracts include Roman Chamomile, Green Tea, Scullcap, Nettle Root, Swertia laponica, Fennel and Aloe Vera extracts. Amount of each of the extracts may range from about 0.001 to about 1%, preferably from about 0.01 to about 0.5%, optimally from about 0.05 to about 0.2% by weight of a composition.
[0029] Additional functional cosmetic additives may also include vitamins such as Vitamin E Acetate, Vitamin C, Vitamin A Palmitate, Panthenol and any of the Vitamin B complexes. Anti-irritant agents may also be present including those of steviosides, alpha-bisabolol and glycyhrizzinate salts, each vitamin or anti-irritant agent being present in amounts ranging from about 0.001 to about 1.0%, preferably from about 0.01 to about 0.3% by weight of the composition.
[0030] These impregnating compositions of the present invention may involve a range of pH although it is preferred to have a relatively low pH, for instance, a pH from about 2 to about 6.5, preferably from about 2.5 to about 4.5.
[0031] In addition to cosmetic compositions, lotions may be incorporated into the nonwoven lightweight wipe. The lotion preferably also comprises one or more of the following: an effective amount of a preservative, an effective amount of a humectant, an effective amount of an emollient; an effective amount of a fragrance, and an effective amount of a fragrance solubilizer.
[0032] As used herein, an emollient is a material that softens, soothes, supples, coats, lubricates, or moisturizes the skin. The term emollient includes, but is not limited to, conventional lipid materials (e.g. fats, waxes), polar lipids (lipids that have been hydrophylically modified to render them more water soluble), silicones, hydrocarbons, and other solvent materials. Emollients useful in the present invention can be petroleum based, fatty acid ester type, alkyl ethoxylate type, fatty acid ester ethoxylates, fatty alcohol type, polysiloxane type, mucopolysaccharides, or mixtures thereof.
[0033] Humectants are hygroscopic materials that function to draw water into the stratum comeum to hydrate the skin. The water may come from the dermis or from the atmosphere. Examples of humectants include glycerin, propylene glycol, and phospholipids.
[0034] Fragrance components, such as perfumes, include, but are not limited to water insoluble oils, including essential oils. Fragrance solubilizers are components which reduce the tendency of the water insoluble fragrance component to precipitate from the lotion. Examples of fragrance solubilizers include alcohols such as ethanol, isopropanol, benzyl alcohol, and phenoxyethanol; any high HLB (HLB greater than 13) emulsifier, including but not limited to polysorbate; and highly ethoxylated acids and alcohols.
[0035] Preservatives prevent the growth of micro-organisms in the liquid lotion and/or the substrate. Generally, such preservatives are hydrophobic or hydrophilic organic molecules. Suitable preservatives include, but are not limited to parabens, such as methyl parabens, propyl parabens, and combinations thereof.
[0036] The lotion can also comprise an effective amount of a kerotolytic for providing the function of encouraging healing of the skin. An especially preferred kerotolytic is Allantoin ((2,5-Dioxo-4-Imidazolidinyl)Urea), a heterocyclic organic compound having an empirical formula C 4 H 6 N 4 O 3 . Allantoin is commercially available from Tri-K Industries of Emerson, N.J. It is generally known that hyperhydrated skin is more susceptible to skin disorders, including heat rash, abrasion, pressure marks and skin barrier loss. A premoistened wipe according to the present invention can include an effective amount of allantoin for encouraging the healing of skin, such as skin which is over hydrated.
[0037] U.S. Pat. No. 5,534,265 issued Jul. 9 , 1996 ; U.S. Pat. No. 5,043,155 issued Aug. 27, 1991; and U.S. Pat. No. 5,648,083 issued Jul. 15, 1997 are incorporated herein by reference for the purpose of disclosing additional lotion ingredients.
[0038] The lotion can further comprise between about 0.1 and about 3 percent by eight Allantoin, and about 0.1 to about 10 percent by weight of an aloe extract, such as aloe vera, which can serve as an emollient. Aloe vera extract is available in the form of a concentrated powder from the Rita Corporation of Woodstock, Ill.
[0039] Further, latherants may be incorporated within the lightweight wipe. Non-limiting examples of anionic lathering surfactants useful in the compositions of the present invention are disclosed in McCutcheon's, Detergents and Emulsifiers, North American edition (1986), published by allured Publishing Corporation; McCutcheon's, Functional Materials, North American Edition (1992); and U.S. Pat. No. 3,929,678, to Laughlin et al., issued Dec. 30, 1975, all of which are incorporated by reference herein in their entirety. A wide variety of anionic lathering surfactants are useful herein. Non-limiting examples of anionic lathering surfactants include those selected from the group consisting of sarcosinates, sulfates, isethionates, taurates, phosphates, lactylates, glutamates, and mixtures thereof.
[0040] Non-limiting examples of nonionic lathering surfactants and amphoteric surfactants for use in the compositions of the present invention are disclosed in McCutcheon's, Detergents and Emulsifiers, North American edition (1986), published by allured Publishing Corporation; and McCutcheon's, Functional Materials, North American Edition (1992); both of which are incorporated by reference herein in their entirety.
[0041] Nonionic lathering surfactants useful herein include those selected from the group consisting of alkyl glucosides, alkyl polyglucosides, polyhydroxy fatty acid amides, alkoxylated fatty acid esters, lathering sucrose esters, amine oxides, and mixtures thereof. The term “amphoteric lathering surfactant,” as used herein, is also intended to encompass zwitterionic surfactants, which are well known to formulators skilled in the art as a subset of amphoteric surfactants.
[0042] A wide variety of amphoteric lathering surfactants can be used in the compositions of the present invention. Particularly useful are those which are broadly described as derivatives of aliphatic secondary and tertiary amines, preferably wherein the nitrogen is in a cationic state, in which the aliphatic radicals can be straight or branched chain and wherein one of the radicals contains an ionizable water solubilizing group, e.g., carboxy, sulfonate, sulfate, phosphate, or phosphonate. Nonlimiting examples of amphoteric or zwitterionic surfactants are those selected from the group consisting of betaines, sultaines, hydroxysultaines, alkyliminoacetates, iminodialkanoates, aminoalkanoates, and mixtures thereof.
[0043] Additional compositions utilized in accordance with the present invention can comprise a wide range of optional ingredients. The CTFA International Cosmetic ingredient Dictionary, Sixth Edition, 1995, which is incorporated by reference herein in its entirety, describes a wide variety of nonlimiting cosmetic and pharmaceutical ingredients commonly used in the skin care industry, which are suitable for use in the compositions of the present invention. Nonlimiting examples of functional classes of ingredients are described at page 537 of this reference. Examples of these functional classes include: abrasives, anti-acne agents, anticaking agents, antioxidants, binders, biological additives, bulking agents, chelating agents, chemical additives, natural additives, colorants, cosmetic astringents, cosmetic biocides, degreasers, denaturants, drug astringents, emulsifiers, external analgesics, film formers, fragrance components, humectants, opacifying agents, plasticizers, preservatives, propellants, reducing agents, skin bleaching agents, skin-conditioning agents (emollient, humectants, miscellaneous, and occlusive), skin protectants, solvents, foam boosters, hydrotropes, solubilizing agents, suspending agents (nonsurfactant), sunscreen agents, ultraviolet light absorbers, and viscosity increasing agents (aqueous and nonaqueous). Examples of other functional classes of materials useful herein that are well known to one of ordinary skill in the art include solubilizing agents, sequestrants, and keratolytics, and the like.
[0044] The aforementioned classes of ingredients are incorporated in a safe and effective amount. The term “safe and effective amount” as used herein, means an amount of an active ingredient high enough to modify the condition to be treated or to deliver the desired skin benefit, but low enough to avoid serious side effects, at a reasonable benefit to risk ratio within the scope of sound medical judgment.
[0045] In addition to home care and personal care end uses, the nonwoven lightweight wipe may be used in industrial and medical applications. For instance, the article may be useful in paint preparation and cleaning outdoor surfaces, such as lawn furniture, grills, and outdoor equipment, wherein the low Tinting attributes of the laminate may be desirable. Aqueous or non-aqueous functional industrial solvents include, oils, such as plant oils, animal oils, terpenoids, silicon oils, mineral oils, white mineral oils, paraffinic solvents, polybutylenes, polyisobutylenes, polyalphaolefins, and mixtures thereof, toluenes, sequestering agents, corrosion inhibitors, abrasives, petroleum distillates, and the combinations thereof.
[0046] A medical lightweight wipe may incorporate an antimicrobial composition, including, but not limited to iodines, alcohols, such as such as ethanol or propanol, biocides, abrasives, metallic materials, such as metal oxide, metal salt, metal complex, metal alloy or mixtures thereof, bacteriostatic complexes, bactericidal complexs, and the combinations thereof.
[0047] The lightweight wipe of the present invention is particularly suitable for dispensing from a tub of stacked, folded wipes, or for dispensing as “pop-up” wipes, in which the lightweight wipe is stored in the tub as a perforated continuous roll, wherein upon pulling a wipe out of the tub, an edge of the next wipe is presented for easy dispensing. The wipes of the present invention can be folded in any of various known folding patterns, such as C-folding, but is preferably Z-folded. A Z-folded configuration enables a folded stack of wipes to be interleaved with overlapping portions. The lightweight wipe may be packaged in various convenient forms, whereby the method of packaging is not meant to be a limitation of the present invention.
[0048] From the foregoing, it will be observed that numerous modifications and variations can be affected without departing from the true spirit and scope of the novel concept of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated herein is intended or should be inferred. The disclosure is intended to cover, by the appended claims, all such modifications as fall within the scope of the claims. | The present invention is directed to a nonwoven fabric, and specifically to a durable lightweight nonwoven fabric wipe, comprising improved strength, as well as an improved MD to CD elongation ratio, which results in a material imminently suitable for application in the cleaning and cleansing of surfaces. A method of making the nonwoven fabric embodying the present invention includes the steps of providing a precursor web comprising a fibrous matrix. The method further comprises the steps of providing a precursor web, which is subjected to hydroentangling. | 3 |
The invention relates to a masonry reinforcement structure comprising parallel cords, more particularly to a masonry bed joint reinforcement structure. The invention also relates to a roll comprising such a masonry reinforcement structure. The invention further relates to masonry reinforced with such masonry reinforcement structure and to a method to apply such masonry reinforcement structure.
BACKGROUND ART
Masonry has a high compressive strength but a limited tensile strength. This leads to limitations in the design of masonry (such as limited height, limited width, limited length of masonry) and may lead to cracking when tensile and/or shear stresses develop in the masonry.
Bed joint reinforcement, for example prefabricated bed joint reinforcement of steel meshwork, is a proven technology for allowing masonry to carry higher loads (e.g. wind loads) by providing additional strength and flexibility, and for controlling cracks in masonry that is subject to tensile forces.
Bed joint reinforcement of steel meshwork for structural use (according to definitions of EN 845:3) generally comprise welded wire meshwork, such as two parallel longitudinal wires connected by a continuous zig-zag wire (truss type) or connected by straight cross wires (ladder type).
Prefabricated bed joint reinforcement structures typically have a length of about 3 m, for example 2.70 m or 3.05 m. This relatively long length makes the transportation, storing and handling of the structures complex.
To secure continuous reinforcement and to avoid weak points in reinforced masonry, overlapping of neighbouring prefabricated bed joint reinforcement elements is necessary and common practice. Overlapping leads to higher material consumption as double amount of material is required in the overlap zones.
Furthermore, as overlaps between neighbouring bed joint reinforcement structures may not be located at areas of high stress or at areas where the dimensions of a section change (for example a step in a wall height or thickness), the work of the installer of bed joint reinforcement elements is complicated.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved masonry reinforcement structure avoiding the drawbacks of the prior art. It is another object of the present invention to provide a masonry reinforcement structure that can easily be rolled up and rolled out. It is a further object of the present invention to provide a masonry reinforcement structure that when rolled out lies and remains in a flat position making additional precautions or steps to obtain a flat position of the masonry reinforcement structure superfluous.
It is a further object of the present invention to provide a masonry reinforcement structure that can be provided in rolls of long length. It is a further object of the present invention to provide a masonry reinforcement structure that makes the use and handling of the masonry reinforcement structure easy, for example the use and handling on a construction site.
It is a further object of the present invention to provide a masonry reinforcement structure that allows to minimize the number of overlaps between neighbouring structures.
It is still a further object of the present invention to provide a masonry reinforcement structure having a minimal thickness allowing easy positioning in the joints (for example glue joints or mortar joints).
According to a first aspect of the present invention a masonry reinforcement structure comprising at least two cords is provided. The masonry reinforcement structure has a length direction. The cords are oriented parallel or substantially parallel in the length direction of the masonry reinforcement structure. The cords comprise metal filaments that are twisted together.
The masonry reinforcement structure according to the present invention comprises preferably a bed joint reinforcement structure.
A bed joint reinforcement structure is defined as a reinforcement structure that is prefabricated for building into a bed joint.
The masonry reinforcement structure has a length L and a width W, with L being larger than W.
With “parallel” or “substantially parallel” is meant that the main axes of the cords are parallel or substantially parallel to each other.
With “substantially parallel” is meant that there may be some deviation from the parallel position. However, if there is a deviation, the deviation from the parallel position is either small or accidental. With small deviation is meant a deviation less than 5 degrees and preferably less than 3 degrees or even less than 1.5 degrees.
The cords of a masonry reinforcement structure according to the present invention are parallel or substantially parallel over the full length of the masonry reinforcement structure. The cords are not intertwisted or interconnected.
Cords
For the purpose of this invention with “a cord” is meant any unit or group of a number of filaments that are twisted. Cords comprise single strand cords or multistrand cords. The twisting can be obtained by cabling or bunching.
A masonry reinforcement structure according to the present invention comprising cords has the advantage that the structure can easily be rolled up and rolled out. Furthermore a masonry reinforcement structures comprising cords lies in a flat position when rolled out and remains in this flat position without requiring additional precautions or steps to obtain or maintain this flat position.
The number of filaments in a cord ranges preferably between 2 and 100, for example between 2 and 81, between 2 and 20, for example 6, 7, 10 or 12.
Filaments
As metal filaments any type of elongated metal filaments can be considered. Any metal can be used to provide the metal filaments. Preferably, the metal filaments comprise steel filaments. The steel may comprise for example high carbon steel alloys, low carbon steel alloys or stainless steel alloys.
The metal filaments preferably have a tensile strength higher than 1000 MPa, for example higher than 1500 MPa or higher than 2000 MPa.
The filaments have a diameter preferably ranging between 0.04 and 2.00 mm. More preferably, the diameter of the filaments ranges between 0.10 and 1 mm as for example between 0.2 and 0.5 mm, for example 0.25, 0.33, 0.37, 0.38 or 0.45 mm.
All filaments of a cord may have the same diameter. Alternatively, a cord may comprise filaments having different diameters.
A cord may comprise one type of filaments. All filaments of a cord have for example the same diameter and the same composition.
Alternatively, a cord may comprise different types of filaments, for example filaments having different diameter and/or different compositions.
The filaments of a cord may all be of the same type, for example all filaments of a cord may comprise metal filaments. Alternatively, a cord comprises non-metal filaments next to metal filaments. Examples of non-metal filaments comprise carbon or carbon based filaments of yarns, polymer filaments or polymer yarns, such as filaments or yarns made of polyamide, polyethylene, polypropylene, polyvinyl alcohol or polyester. Also glass yarns or rovings of glass filaments can be considered.
The filaments preferably have a circular or substantially circular cross-section although filaments with other cross-sections, such as flattened filaments or filaments having a square or a substantially square cross-section or having a rectangular or a substantially rectangular cross-section can be considered as well.
The filaments can be uncoated or can be coated with a suitable coating, for example a coating giving corrosion protection.
Suitable coatings comprise a metal coating such as a zinc or zinc alloy coating or a polymer coating. Examples of metal or metal alloy coatings comprise zinc or zinc alloy coatings, for example zinc brass coatings, zinc aluminium coatings or zinc aluminium magnesium coatings. A further suitable zinc alloy coating is an alloy comprising 2 to 10% Al and 0.1 to 0.4% of a rare earth element such as La and/or Ce.
Examples of polymer coatings comprise polyethylene, polypropylene, polyester, polyvinyl chloride or epoxy.
For a person skilled in the art it is clear that a coating such as a coating giving corrosion protection can be applied on the filaments. However, it is also possible that a coating is applied on a cord.
Number of Cords
A masonry reinforcement structure according to the present invention comprises at least two cords. In principle there is no limitation to the number of cords. Preferably, the number of cords ranges between 2 and 500, for example between 4 and 300. The number of cords is for example 10, 20, 50, 100, 200 or 300.
Preferably, the different cords of a masonry reinforcement structure according to the present invention are spaced apart. The distance between cords may vary within a wide range, the distance between neighbouring cords is for example higher than 1 mm and lower than 80 cm. The distance between neighbouring is for example ranging between 1 mm and 10 cm, for example 5 mm, 1 cm, 2 cm, 3 cm, 5 cm, 7 cm or 8 cm. For many applications a minimum distance between neighbouring cords is preferred as this results in a better embedment of the cords in the mortar or glue.
The distance between neighbouring cords can be equal over the width of the structure of the masonry reinforcement structure.
Alternatively, it can be preferred that the distance between neighbouring cords is lower in some areas of the masonry reinforcement structure, for example in areas where stresses are high.
The distance between neighbouring cords can for example be lower at the outer sides of the masonry reinforcement structure compared to the distance between neighbouring cords in the middle portion of the masonry reinforcement structure.
A masonry reinforcement structure according to the present invention may comprise one type of cords. All cords of a masonry reinforcement structure have for example the same construction and comprise the same material.
Alternatively, a masonry reinforcement structure comprises a number of different types of cords, for example cords having a different construction.
A masonry reinforcement structure according to the present invention comprises cords that are in a mutual parallel position or in a mutual substantially parallel position oriented in the length direction of the masonry reinforcement structure.
Preferably, the cords are kept and secured in their mutual parallel or mutual substantially parallel position and this during manufacturing, transporting, installation and once installed.
The cords are for example kept in their mutual parallel or mutual substantially parallel position by coupling the cords to a substrate or by integrating the cords in a structure.
The term ‘coupled to a substrate’ should be understood in a broad meaning and includes all possible manners whereby the cords are coupled to a substrate. For the purpose of this invention coupling includes connecting, joining, bonding, gluing, adhering, laminating . . . . The cords can be coupled, joined, bonded, glued, adhered, laminated to the substrate by any technique known in the art. Preferred techniques comprise stitching, knitting, embroidering, gluing, welding and melting. As substrate any substrate allowing the coupling of the cords to can be considered, either substrates comprising a metal or a non-metal material or substrates comprising both a metal and a non-metal material. Suitable substrates comprise woven structures, non-woven structures, films, strips, foils, meshes, grids or foams.
As non-woven substrates needlebonded, waterbonded, spunbonded, airlaid, wetlaid or extruded substrates can be considered.
Preferred foils or grids are foils or grids obtained by extrusion, for example foils or grids comprising polypropylene, polyethylene, polyamide, polyester or polyurethane.
Preferred metal substrates comprise metal grids or metal meshes, for example steel grids or steel meshes.
The substrate may comprise an open structure or alternatively a closed structure. A substrate having an open structure has the advantage that it is permeable for the glue or mortar when installed in the masonry. Furthermore open structures have a lower weight and higher flexibility.
Substrates comprising a non-metal material comprise for example glass, carbon or polymer material. Preferred polymer materials comprise polyester, polyamide, polypropylene, polyethylene, polyvinyl alcohol, polyurethane, polyethersulphone, or any combination thereof.
As metal substrates steel substrates, for example substrates made of steel wire such as meshes or grids can be considered.
A preferred way of coupling the cords to a substrate is by gluing the cords to a substrate, for example a substrate comprising carbon or carbon based filaments of yarns, polymer filaments or polymer yarns or glass yarns or rovings. Any type of glue of hot melt suitable to couple the cords to the substrate can be considered.
Another preferred way of coupling the cords to a substrate is by using at least one yarn. Possibly, the number of yarns used is higher than 1. The number of yarns is for example ranging between 1 and 100; for example ranging between 1 and 50, for example 10.
The at least one yarn holds the cords in their mutual parallel or substantially parallel position and ensures that the cords are secured in their mutual parallel or mutual substantially parallel position and this during the manufacturing, storing, transporting, installation and use of the masonry reinforcement structure.
Preferably, the at least one yarn forms stitches to couple the cords to the substrate. The stitches are preferably formed around the cords. The stitches are preferably formed by at least one operation selected from stitching, knitting or embroidering.
Yarn
The yarn comprises preferably a textile yarn.
For the purpose of this invention with “yarn” is meant any fiber, filament, multifilament of long length suitable for use in the production of textiles. Yarns comprise for example spun yarns, zero-twist yarns, single filaments (monofilaments) with or without a twist, narrow strip of materials with or without twist, intended for use in a textile structures.
The at least one yarn may comprise a natural material, a synthetic material or a metal or metal alloy.
Preferred synthetic materials comprise polyamide, polyether sulphone, polyvinyl alcohol and polypropylene yarn. Also yarns made of glass, such as glass fibers can be considered.
Preferred metal or metal alloys comprise steel such as low carbon steel, high carbon steel or stainless steel.
Preferably, the yarn used in the structure for the masonry reinforcement structure is suitable for use in a textile operation such as sewing, stitching, knitting, embroidery and weaving.
In order to be suitable in a textile operation and more particularly in a sewing, knitting or embroidery operation, the yarn is preferably bendable.
Preferably, the at least one yarn can be bent to a radius of curvature smaller than 5 times the equivalent diameter of the yarn. More preferably the at least one yarn can be bent to a radius of curvature lower than 4 times the diameter of the yarn, lower than 2 times the diameter of the yarn or even lower than the diameter of the yarn.
Furthermore the yarn used is preferably suitable to hold and secure the cords in their mutual parallel or mutual substantially parallel position. It is clear that the yarn used preferably allows to maintain the flexibility of the structure so that the structure can be rolled up and rolled out easily.
Also the term ‘integrated in a structure’ should be understood in a broad meaning and includes all possible manners whereby the cords are integrated in a structure or substrate. For the purpose of this invention integrating the cords in a structure includes embedding the cords in a matrix material such as a polymer matrix material. The cords are for example embedded in a polymer strip.
Integrating the cords in a structure also includes the integration of the cords during the manufacturing of the structure, for example the integration of the cords in a woven structure during the manufacturing of the woven structure or of a knitted structure during the manufacturing of the knitted structure. Similarly, the cords can be integrated in a non-woven structure during the manufacturing of the non-woven structure. For a woven structure the cords are for example integrated in the warp direction of the woven structure. For a knitted structure the cords are for example integrated in the longitudinal direction of the knitted structure.
In a preferred embodiment the masonry reinforcement structure comprises a woven structure comprising cords in the warp direction. The weft direction comprises for example the least one yarn. In such woven structure the cords are hold in their mutual parallel or mutual substantially parallel position by the at least one yarn.
For a person skilled in the art it is clear that a woven fabric according to the present invention may comprise other elements such as yarns in the warp direction next to the cords.
The woven fabric according to the present invention may also comprise cords in the weft direction.
In another preferred embodiment the masonry reinforcement structure comprises a knitted structure wherein the stitches are formed by at least one yarn.
Thanks to the high flexibility of the masonry reinforcement structure, the masonry reinforcement structure can easily be rolled up and rolled out. Furthermore when rolled out the masonry reinforcement structure lies in a flat position and remains in a flat position without requiring additional precautions or steps to obtain a flat position.
This makes the use at a construction site easy. The masonry reinforcement structure can be rolled out on a masonry structure, for example on a layer of bricks or blocks.
The masonry reinforcement structure can be easily cut to the required length.
As the masonry reinforcement structure can be provided at long lengths, the number of overlaps between neighbouring masonry reinforcement structures is substantially reduced compared to masonry reinforced with prefabricated bed joint reinforcement structures presently known in the art.
A further advantage of a masonry reinforcement structure according to the present invention is the minimal thickness of the masonry reinforcement structure allowing easy positioning in the joints (for example glue joints or mortar joints).
The masonry reinforcement structure may have an open structure or alternatively a closed structure. A masonry reinforcement structure having an open structure has the advantage that it that it is permeable for the glue or mortar. Furthermore open structures have a lower weight and higher flexibility.
In preferred embodiments the masonry reinforcement structure consists of metal, for example of steel. As such masonry reinforcement structure consists of one material, this may simplify the recycling of the masonry reinforcement structure or of a masonry structure reinforced with a masonry reinforcement structure.
Examples of masonry reinforcement structures consisting of steel comprise
steel cords coupled to a steel substrate, for example steel cords coupled to a steel mesh by means of a steel yarn; steel cords integrated in a woven structure, for example a woven structure consisting of steel cords and a steel yarn or a number of steel yarns; steel cords integrated in a knitted structure, for example a knitted structure consisting of steel cords and a steel yarn or a number of steel yarns.
According to a second aspect of the present invention a method to manufacture a masonry reinforcement structure is provided.
The method comprises the steps of:
providing at least two cords, said cords comprising twisted filaments; manufacturing a masonry reinforcement structure comprising said at least two cords, said at least two cords being oriented parallel or substantially parallel in the length direction of the masonry reinforcement structure.
A preferred method of manufacturing a masonry reinforcement structure according to the present invention comprises the steps of
providing at least two cords; providing a substrate; coupling said at least two cords to said substrate in a substantially parallel direction in the length direction of said structure.
The coupling of the at least two cords to the substrate is preferably obtained by stitching, knitting, embroidering, gluing, laminating, welding or melting.
A further method of manufacturing a masonry reinforcement structure according to the present invention comprises the steps of
providing at least two cords of twisted filaments; integrating said at least two cords in said structure during the manufacturing of said structure.
The cords are for example integrated in a polymer strip, for example during extrusion of the polymer material.
In other methods, the cords are integrated in a woven structure, for example during the weaving of the woven structure. The cords are for example integrated in the warp direction of the woven structure. In a further method the cords are integrated in a knitted structure, for example during the manufacturing of the knitted structure.
In still a further method, the cords are integrated in a non-woven structure, for example in a spunlaid or wetlaid structure during the manufacturing of the structure.
Still a further method of manufacturing a masonry reinforcement structure according to the present invention comprises the steps of
providing at least two cords, said cords comprising twisted filaments; providing a substrate; manufacturing a welded, woven, knitted or braided structure comprising said at least two cords in a substantially parallel direction in the length direction of said structure; coupling said welded, woven, knitted or braided structure to said substrate, preferably by stitching, knitting, embroidering, gluing, welding or melting.
According to a third aspect of the present invention a roll of a masonry reinforcement structure as described above is provided. The masonry reinforcement structure is wound or coiled to form said roll.
As the masonry reinforcement structure according to the present invention is flexible, the structure can easily be rolled up and rolled out.
According to a fourth aspect of the present invention a method to install a masonry reinforcement structure as described above is provided.
The method to install the masonry reinforcement structure comprises the steps of
providing masonry comprising at least one layer of units or bricks; uncoiling a masonry reinforcement structure as described above and if required cutting the masonry reinforcement structure to the desired length; installing said masonry reinforcement structure in a joint (for example in a mortar or glue joint) on the upper surface of the last layer of units or bricks; providing the next layer of units or bricks on said joint.
The masonry reinforcement structure can be installed in said joint by first applying a layer of mortar or glue on the upper surface of the last layer of units or bricks and by subsequently applying the masonry reinforcement structure.
Alternatively, the masonry reinforcement structure can be installed in said joint by first applying the masonry reinforcement structure on the upper surface of the last layer of units or bricks and by subsequently applying a layer of mortar or glue on the masonry reinforcement structure.
In a further method a first layer of mortar or glue is applied on the upper surface of the last layer of units or bricks, the masonry reinforcement structure is applied on the masonry reinforcement structure, followed by the application of a second layer of mortar or glue on the masonry reinforcement structure.
According to a fifth aspect of the present invention masonry reinforced with at least one masonry reinforcement structure according to the present invention is provided.
The masonry comprises a number of layers of units or bricks and joints between two neighbouring layers of units or bricks. At least one joint is reinforced by a masonry reinforcement structure according to the present invention.
The joints may comprise mortar joints or glue joints.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described into more detail with reference to the accompanying drawings whereby
FIG. 1 is an illustration of a masonry reinforcement structure comprising cords glued to a substrate;
FIG. 2 is an illustration of a masonry reinforcement structure comprising cords stitched to a substrate;
FIG. 3 is an illustration of a masonry reinforcement structure comprising cords in a woven structure;
FIG. 4 is an illustration of a masonry reinforcement structure comprising an alternative woven structure;
FIG. 5 is an illustration of a masonry reinforcement structure comprising cords in a knitted structure;
FIG. 6 is an illustration of a masonry reinforcement structure comprising cords embedded in a polymer material.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.
The following terms are provided solely to aid in the understanding of the inventions:
Masonry: all building systems that are constructed by stacking units of for example stone, clay, or concrete, joined by for example mortar or glue into the form of for example walls, columns, arches, beams or domes;
Equivalent diameter of a yarn or filament: the diameter of an imaginary yarn or filament having a circular radial cross-section, which cross-section has a surface identical to the surface area of the particular yarn or filament
FIG. 1 is an illustration of a masonry reinforcement structure 100 comprising parallel cords 102 glued to a substrate 110 . A preferred steel cord 102 comprises between 2 and 12 filaments, for example a cord having one core filament having a diameter of 0.37 mm and 6 filaments having a diameter of 0.33 m around this core filament (0.37+6×0.33). The steel cords 102 are oriented in a substantially parallel position. The substrate 110 comprises for example a woven or non-woven polymer structure. Preferably, the substrate 110 has an open structure.
The steel cords 102 are glued to a substrate 110 .
The substrate 110 may comprise a polymer material, glass, carbon, metal such as steel or any combination thereof. The substrate 110 is for example a grid or foil obtained by extrusion. Alternatively the substrate 110 comprises a woven or non-woven structure, for example a woven or non-woven polymer structure or a woven or non-woven metal substrate. Examples of non-woven structures comprise a needlepunched or spunbond non-woven substrate, for example in polyamide, polyether sulphone of polypropylene.
In a preferred embodiment the structure 100 comprises steel cords 102 that are glued to a non-woven polyether sulphone substrate 110 or to an extruded polypropylene grid (35 g/m 2 having a 6×6 mm mesh). In another preferred embodiment the structure 100 comprises steel cords 102 that are glued to a substrate 110 made of glass fibers or glass rovings or to a substrate 110 comprising carbon filaments.
FIG. 2 is an illustration of a masonry reinforcement structure 200 comprising parallel cords 202 stitched to a substrate 210 by means of yarn 204 . The cords 202 are for example steel cords comprising 3 filaments having a diameter of 0.48 mm twisted together (3×0.48 mm). The yarn 204 forms stitches to hold the cords 202 in their mutual parallel or mutual substantially parallel position.
The substrate 210 comprises for example a woven or non-woven polymer structure.
In a preferred embodiment the cords comprise steel cords that are stitched to a polymer substrate for example a non-woven polyether sulphone substrate by means of a polyether sulphone yarn.
In another preferred embodiment the cords are steel cords stitched to a metal substrate, for example a steel mesh or steel grid by a metal yarn, for example a steel yarn. Such structure fully consisting of one material, more particularly metal (steel) is easier to recycle compared to structures comprising a number of different materials.
FIG. 3 is an illustration of a masonry reinforcement structure 300 comprising a woven structure. The woven structure 300 comprises steel cords 302 in the warp direction. A preferred steel cord comprises between 2 and 12 filaments, for example a cord having one core filament having a diameter of 0.37 mm and 6 filaments having a diameter of 0.33 m around this core filament (0.37+6×0.33).
The weft direction comprises for example a polymer yarn 304 , such as a polyamide, a polyether sulphone, a polyvinyl alcohol or a polypropylene yarn.
The masonry reinforcement structure 300 is preferably an open structure permeable for the glue or mortar.
It is clear for a person skilled in the art that different weave patterns can be considered.
FIG. 4 shows a second embodiment of a woven masonry reinforcement structure 400 . The masonry reinforcement structure 400 comprises cords integrated in a woven structure 400 . The woven structure 400 comprises in the warp direction a combination of polymer yarns 403 and steel cords 402 . The weft direction comprises a polymer yarn 404 .
FIG. 5 shows a masonry reinforcement structure 500 comprising a knitted structure. The knitted structure 500 comprises steel cords 502 as pillar threads. The steel cords 502 comprise for example steel cords comprising 3 filaments having a diameter of 0.48 mm twisted together (3×0.48 mm). Another suitable steel cord comprises a cord having one core filament having a diameter of 0.6 mm and 5 filaments having a diameter of 0.73 mm around this core filament (0.6+5×0.73 mm). The structure further comprises yarn 504 and yarn 506 to keep the steel cords in their mutual parallel or mutual substantially parallel position. The yarn 504 is for example a multifilament yarn, preferably a polyamide, a polyether sulphone, a polyvinyl alcohol or a polypropylene yarn. The yarn 504 may also comprise a metal yarn.
The yarn 506 is connecting neighbouring steel cords 502 . The monofilament yarn 506 is preferably a polyamide, a polyether sulphone, a polyvinyl alcohol or a polypropylene yarn. The yarn 506 may also comprise a metal yarn.
FIG. 6 is an illustration of a masonry reinforcement structure 400 comprising cords 602 embedded in strip of a polymer material 604 . | A masonry reinforced with at least one bed joint masonry reinforcement structure. The bed joint reinforcement structure includes at least two cords, which have metal filaments that are twisted together. The cords are oriented parallel or substantially parallel in the length direction of the masonry reinforcement structure. | 3 |
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation-in-part of each of: U.S. patent application Ser. No. 12/363,210, filed on Jan. 30, 2009; and U.S. Patent application Ser. No. 12/331,350, filed on Dec. 9, 2008(now U.S. Pat. No. 8,109,219), both of which are hereby incorporated by reference.
BACKGROUND ART
Lashing materials (e.g., laces, rope, twine, cables, tie-straps, etc.) have long been used to secure at least one object or space, often through the use of one or more eyelets fixedly coupled to the object or a securing measure, such as a tarp, cargo net, or canopy. Various examples of the same, featuring fixed configurations, can be found in everyday life. These measures generally rely upon frictional interaction between the lashing material and eyelet(s), as well as manipulation (e.g., tying of knots into, and/or formation of loops by the lashing material, etc.) to fixedly retain the secured relationship. Where manipulation is reversed (e.g., the knot is loosened), it is appreciated that the interactive friction and threaded eyelet configuration is typically incapable of maintaining the secured relationship, and that as a result an insecure relationship may occur.
BRIEF SUMMARY
The present invention concerns a securing assembly comprising active lashing material and/or eyelet that use active material actuation to better or more facilely secure a cargo or space. More particularly, the assembly is useful for selectively modifying the interaction between the lashing material and eyelets, so as to facilitate threading, promote a more secured relationship, provide a holding mechanism that retains the lashing material in the more secured relationship when the active material element is deactivated, and/or facilitate unlashing when removal is desired. The invention enables attenuated tensioning of and selectively reducing slack in the lashing material, and is useful for dissipating shock loads transmitted to anchor points, and from the points to any tied-down cargo.
Thus, in general, the invention presents a securing assembly adapted for fixing at least one object, so as to achieve a secured relationship. The assembly includes at least one eyelet defining an inside diameter, and a lashing material defining a general cross-sectional diameter less than the inside diameter, so as to be threaded through said at least one eyelet. Either the eyelet(s) and/or material further comprise an active material element operable to undergo a change in fundamental property when exposed to or occluded from an activation signal, so as to be activated and deactivated, respectively. The change in fundamental property is used to modify the inside or cross-sectional diameter (or the tension such as through slack removal in the lacing material), so as to further secure said at least one object or facilitate threading the lashing.
Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiment(s) and the accompanying drawing figures.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
A preferred embodiment(s) of the invention is described in detail below with reference to the attached drawing figures, wherein:
FIG. 1 is an elevation of a flat bed truck having a cargo stored thereupon, and a securing assembly engaging the cargo, and comprising a tarp, lashing material, and plurality of eyelets, in accordance with a preferred embodiment of the invention;
FIG. 2 is an elevation of a flat bed truck having a cargo stored thereupon, and a securing assembly engaging the cargo and comprising a plurality of tie straps, and toggle clamps, in accordance with a preferred embodiment of the invention, and further, in enlarged caption view, shape memory alloy and heating elements woven and embedded within the strap;
FIG. 3 is a partial elevation of a lashing material threaded through a plurality of opposite eyelets, and forming a loop, in accordance with a preferred embodiment of the invention;
FIG. 3 a is a partial elevation of the rope and eyelets shown in FIG. 3 , wherein the lashing material has been tightened, and the eyelets deformed;
FIG. 3 b is a partial elevation of the lashing material and eyelets shown in FIG. 3 , wherein the lashing material has been tightened and the eyelets displaced;
FIG. 4 is a longitudinal section of a lashing material comprising active inserts, in accordance with a preferred embodiment of the invention; and
FIG. 5 is a perspective view of a shoe incorporating an active shoe lace and/or eyelets, in accordance with a preferred embodiment of the invention.
DETAILED DESCRIPTION
Referring to FIGS. 1-5 , the present invention concerns a securing assembly 10 including an active lashing material 12 and at least one eyelet 14 for receiving the material 12 . That is to say, the lashing material 12 , and/or eyelet(s) comprise an active material element 16 in various geometric forms (e.g., wires, straps, cable strands, beads, rings, etc.). The assembly 10 is contemplated for on-demand and/or passive use in a wide variety of applications, and more particularly, wherever lashing/lacing materials are used to secure a cargo (e.g., one or more objects) 100 . In a particular embodiment, the assembly 10 composes an article of clothing or footwear 102 ( FIG. 5 ), so as to be used to further support or add comfort to a body part (not shown). Other applications include tie-downs for uniform tensioning of cargo, boat, and seat covers, and more particularly, to a self-tightening and/or slack eliminating drawstring that is pseudoplastically stretched to provide a larger opening or perimeter for ease of insertion/application and then activated to reduce the size of the opening or perimeter. The following description of the preferred embodiments of the invention is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
As used herein the term “active material” shall be afforded its ordinary meaning as understood by those of ordinary skill in the art, and includes any material or composite that exhibits a reversible change in a fundamental (e.g., chemical or intrinsic physical) property, when exposed to an external signal source. Suitable active materials for use with the present invention include but are not limited to shape memory alloys, and electroactive polymers (EAP) that can function as actuators under fibrous configurations and atmospheric conditions. These types of active materials have the ability to remember their original shape and/or elastic modulus, which can subsequently be recalled by applying or removing an external stimulus. As such, deformation from the original shape is a temporary condition. In this manner, an element composed of these materials can change to the trained shape in response to either the application or removal (depending on the material and the form in which it is used) of an activation signal.
More particularly, shape memory alloys (SMA's) generally refer to a group of metallic materials that demonstrate the ability to return to some previously defined shape or size when subjected to an appropriate thermal stimulus. Shape memory alloys are capable of undergoing phase transitions in which their yield strength, stiffness, dimension and/or shape are altered as a function of temperature. The term “yield strength” refers to the stress at which a material exhibits a specified deviation from proportionality of stress and strain. Generally, in the low temperature, or martensite phase, shape memory alloys can be pseudo-plastically deformed and upon exposure to some higher temperature will transform to an austenite phase, or parent phase, returning to their shape prior to the deformation. Materials that exhibit this shape memory effect only upon heating are referred to as having one-way shape memory. Those materials that also exhibit shape memory upon re-cooling are referred to as having two-way shape memory behavior.
Shape memory alloys exist in several different temperature-dependent phases. The most commonly utilized of these phases are the so-called Martensite and Austenite. In the following discussion, the Martensite phase generally refers to the more deformable, lower temperature phase whereas the Austenite phase generally refers to the more rigid, higher temperature phase. When the shape memory alloy is in the martensite phase and is heated, it begins to change into the austenite phase. The temperature at which this phenomenon starts is often referred to as austenite start temperature (A s ). The temperature at which this phenomenon is complete is called the austenite finish temperature (A f ).
When the shape memory alloy is in the austenite phase and is cooled, it begins to change into the martensite phase, and the temperature at which this phenomenon starts is referred to as the martensite start temperature (M s ). The temperature at which austenite finishes transforming to martensite is called the martensite finish temperature (M f ). Thus, a suitable activation signal for use with shape memory alloys is a thermal activation signal having a magnitude to cause transformations between the martensite and austenite phases.
Shape memory alloys can exhibit a one-way shape memory effect, an intrinsic two-way effect, or an extrinsic two-way shape memory effect depending on the alloy composition and processing history. Annealed shape memory alloys typically only exhibit the one-way shape memory effect. Sufficient heating subsequent to low-temperature deformation of the shape memory material will induce the martensite to Austenite phase transformation, and the material will recover the original, annealed shape. Hence, one-way shape memory effects are only observed upon heating. Active materials comprising shape memory alloy compositions that exhibit one-way memory effects do not automatically reform, and will likely require an external mechanical force to reform the shape that was previously suitable for airflow control.
Intrinsic and extrinsic two-way shape memory materials are characterized by a shape transition both upon heating from the martensite phase to the austenite phase, as well as an additional shape transition upon cooling from the austenite phase back to the martensite phase. Active materials that exhibit an intrinsic shape memory effect are fabricated from a shape memory alloy composition that will cause the active materials to automatically reform themselves as a result of the above noted phase transformations. Intrinsic two-way shape memory behavior must be induced in the shape memory material through processing. Such procedures include extreme deformation of the material while in the martensite phase, heating-cooling under constraint or load, or surface modification such as laser annealing, polishing, or shot-peening. Once the material has been trained to exhibit the two-way shape memory effect, the shape change between the low and high temperature states is generally reversible and persists through a high number of thermal cycles. In contrast, active materials that exhibit the extrinsic two-way shape memory effect are composite or multi-component materials. They combine an alloy that exhibits a one-way effect with another that provides a restoring force to reform the original shape.
The temperature at which the shape memory alloy remembers its high temperature form when heated can be adjusted by slight changes in the composition of the alloy and through heat treatment. In nickel-titanium shape memory alloys, for instance, it can be changed from above about 100° C. to below about −100° C. The shape recovery process occurs over a range of just a few degrees and the start or finish of the transformation can be controlled to within a degree or two depending on the desired application and alloy composition. The mechanical properties of the shape memory alloy vary greatly over the temperature range spanning their transformation, typically providing the system with shape memory effects, superelastic effects, and high damping capacity.
Suitable shape memory alloy materials include, without limitation, nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys (e.g., copper-zinc alloys, copper-aluminum alloys, copper-gold, and copper-tin alloys), gold-cadmium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, iron-platinum based alloys, iron-platinum based alloys, iron-palladium based alloys, and the like. The alloys can be binary, ternary, or any higher order so long as the alloy composition exhibits a shape memory effect, e.g., change in shape orientation, damping capacity, and the like.
It is appreciated that SMA's exhibit a modulus increase of 2.5 times and a dimensional change (recovery of pseudo-plastic deformation induced when in the Martensitic phase) of up to 8% (depending on the amount of pre-strain) when heated above their phase transition temperature. It is appreciated that where the SMA is one-way in operation, a biasing force return mechanism (such as a spring) would be required to return the SMA to its starting configuration. Finally, it is appreciated that Joule heating can be used to make the entire system electronically controllable.
Stress induced phase changes in SMA, caused by loading and unloading of SMA (when at temperatures above A f ), are, however, two way by nature. That is to say, application of sufficient stress when an SMA is in its austenitic phase will cause it to change to its lower modulus martensitic phase in which it can exhibit up to 8% of “superelastic” deformation. Removal of the applied stress will cause the SMA to switch back to its austenitic phase in so doing recovering its starting shape and higher modulus, and dissipating energy. More particularly, the application of an externally applied stress causes martensite to form at temperatures higher than M s . The macroscopic deformation is accommodated by the formation of martensite. When the stress is released, the martensite transforms back into austenite and the SMA returns back to its original shape. Superelastic SMA can be strained several times more than ordinary metal alloys without being plastically deformed, however, this is only observed over a specific temperature range, with the largest ability to recover occurring close to A f .
As previously mentioned, it is appreciated that other types of active materials, such as electroactive polymers may be used in lieu of SMA. This type of active material includes those polymeric materials that exhibit piezoelectric, pyroelectric, or electrostrictive properties in response to electrical or mechanical fields. An example of an electrostrictive-grafted elastomer with a piezoelectric poly(vinylidene fluoride-trifluoro-ethylene) copolymer. This combination has the ability to produce a varied amount of ferroelectric-electrostrictive, molecular composite systems. These may be operated as a piezoelectric sensor or even an electrostrictive actuator.
Materials suitable for use as an electroactive polymer may include any substantially insulating polymer or rubber (or combination thereof) that deforms in response to an electrostatic force or whose deformation results in a change in electric field. Exemplary materials suitable for use as a pre-strained polymer include silicone elastomers, acrylic elastomers, polyurethanes, thermoplastic elastomers, copolymers comprising PVDF, pressure-sensitive adhesives, fluoroelastomers, polymers comprising silicone and acrylic moieties, and the like. Polymers comprising silicone and acrylic moieties may include copolymers comprising silicone and acrylic moieties, polymer blends comprising a silicone elastomer and an acrylic elastomer, for example.
Materials used as an electroactive polymer may be selected based on one or more material properties such as a high electrical breakdown strength, a low modulus of elasticity—(for large deformations), a high dielectric constant, and the like. In one embodiment, the polymer is selected such that is has an elastic modulus at most about 100 MPa. In another embodiment, the polymer is selected such that is has a maximum actuation pressure between about 0.05 MPa and about 10 MPa, and preferably between about 0.3 MPa and about 3 MPa. In another embodiment, the polymer is selected such that is has a dielectric constant between about 2 and about 20, and preferably between about 2.5 and about 12. The present disclosure is not intended to be limited to these ranges. Ideally, materials with a higher dielectric constant than the ranges given above would be desirable if the materials had both a high dielectric constant and a high dielectric strength.
As electroactive polymers may deflect at high strains, electrodes attached to the polymers should also deflect without compromising mechanical or electrical performance. Generally, electrodes suitable for use may be of any shape and material provided that they are able to supply a suitable voltage to, or receive a suitable voltage from, an electroactive polymer. The voltage may be either constant or varying over time. In one embodiment, the electrodes adhere to a surface of the polymer. Electrodes adhering to the polymer are preferably compliant and conform to the changing shape of the polymer. Correspondingly, the present disclosure may include compliant electrodes that conform to the shape of an electroactive polymer to which they are attached. The electrodes may be only applied to a portion of an electroactive polymer and define an active area according to their geometry. Various types of electrodes suitable for use with the present disclosure include structured electrodes comprising metal traces and charge distribution layers, textured electrodes comprising varying out of plane dimensions, conductive greases such as carbon greases or silver greases, colloidal suspensions, high aspect ratio conductive materials such as carbon fibrils and carbon nanotubes, and mixtures of ionically conductive materials.
In a preferred embodiment, wherein the lashing material (e.g., lace, rope, thread, cable, tether, etc.) 12 is formed of a suitable active material as delineated above, the invention may be used to eliminate slack by selectively activating the active material. Activation may also be used to effect more uniform tensioning along the longitudinal profile of the material 12 . In each of the examples and embodiments described below, it is appreciated that plural separately actuated active material elements 16 may be employed, so as to effect redundancy, and variable strokes. Where the lashing material 12 comprises shape memory alloy wire 16 in a normally Martensitic state, situational tightening may be accomplished by thermally activating the shape memory alloy element 16 through Joule heating. To that end, the lashing material 12 , such as a series of tethers ( FIG. 1 ), or cargo straps ( FIG. 2 ) may be electrically coupled to a signal source 18 . In an automotive application, for example, the signal source 18 may be the vehicle charging system (e.g., battery, etc.). In FIG. 1 , for example, a series of prongs 20 which anchor the tethers on each side of the truck bed may be electrically coupled to the tethers via contacts (not shown).
Alternatively, a heating element 22 may be included within the lashing material 12 , and coupled to the signal source 18 , so as to be operable to generate enough heat energy to activate the shape memory alloy element(s) 16 ( FIG. 2 ). For example, the lashing material 12 may include a fabric formed of shape memory alloy wires 16 and thermally resistive elastic fibers, and an electrically resistive heating wire 22 embedded within the fabric. In lieu of or addition to the resistive wire, the heating element 22 may present a conduit fluidly coupled to and operable to convey a heated or cooling fluid (e.g., engine coolant) may be disposed inside the fabric. The resistive wire or conduit 22 is configured such that the lashing material 12 is able to shorten in effective length (e.g., able to adopt a more sinuous longitudinal profile), when the element 16 is activated or deactivated.
In another embodiment, the lashing material 12 comprises shape memory alloy in a normally Austenitic state, and is passively activated by utilizing the superelastic effect thereof. That is to say, when the lashing material 12 is caused to undergo a sufficient stress load, it is caused to transform from the Austenite to the more malleable Martensite phase, thus, producing give in the material 12 , and upon return to the Austenite phase, energy dissipation. In this configuration, the non-active structure of the lashing material 12 must therefore, be configured to stretch or lengthen. In this embodiment, it is appreciated that the constant binding force and energy dissipation offered thereby allows securement of more delicate objects, and that the asymmetric stiffness compensates for cold weather or vibration induced slackening, while increasing the binding force for hot weather-induced expansion.
Where an EAP element(s) 16 is used, the signal source 18 is operable to apply a voltage directly thereto, so as to change the tension within the lashing material 12 . In another mode of operation, a voltage is applied to the EAP element(s) 16 to selectively lengthen the lashing material 12 and produce slack. The act of lacing and lashing is then performed while facilitated by the generated slack. Once complete, the voltage is removed causing the slack to be removed and material 12 to tighten and achieve the more secured relationship. It is appreciated that a voltage could then be reapplied to facilitate unlacing and unlashing. Finally, it is also appreciated that the entire lashing material 12 may be formed of active material. For example, the active material element 16 , as springs, flats, wires, cables, braids, etc., may be used as straps 12 themselves, or integrated into straps made of other elastomeric or stretchable materials as segments, laminates, cables, or wires woven into, embedded in, or otherwise mechanically coupled.
The preferred assembly 10 further includes toggle clamps 24 configured for securing and imparting a desired tension to the lashing material (e.g., straps, cables, etc.) 12 ( FIG. 2 ). To the extent that the lashing material comprises an electrically activated active material element 16 , the clamp 24 may present the necessary contacts/lead. For example the distal end of the lashing material may be coupled to a male connector (not shown), while the toggle clamp 24 defines a female receptacle (also not shown) configured to securely receive the male connector. Thus, in exemplary operation, the clamps 24 are released to enable engagement with a tie strap 12 comprising an SMA element 16 . The clamp 24 is then closed thereby stretching the Martensitic SMA or taking up the slack in the strap 12 depending on its starting length. The element 16 is then heated, so as to cause it to transform and shorten. Where the strap 12 was relatively taut, activation causes the strap 12 to conform to and apply an even compressive force on the cargo 100 . The imparted force is bounded by stress-induced Austenitic to Martensitic transformation, which reduces the chance of over-tightening. Upon cooling, the SMA element 16 retains its reduced length, with some allowance for two-way SMA, and thus, continues to impart force. Otherwise, when access to the cargo 100 is desired, the clamps 24 are released conventionally.
FIGS. 3-5 show interaction between a lashing material 12 , such as a lace, and a plurality of (e.g., four) eyelets 14 . Each eyelet 14 defines an eye 14 a that presents an inside diameter. In each embodiment, the lace 12 has been threaded through each eyelet 14 and then doubled-over back through the first two vertically adjacent eyelets 14 , so as to form a loop. The lace 12 may be active as previously described, such that activation causes the loop to contract and close. Where the eyelets 14 are non-deformable ( FIG. 3 b ), this action causes them to translate towards each other, thus producing a more secure relationship. Alternatively, the eyelets 14 may be deformable, such that contracting the loop causes them to collapse towards each other and achieve a more ellipsoidal configuration ( FIG. 3 a ). This may be accomplished with elastomeric eyelets 14 presenting a modulus of elasticity that balances support with energy dissipation and give.
In another example, the eyelets 14 are drivenly coupled to an active material element 16 . More preferably, the eyelets 14 are formed at least in part of Martensitic SMA having an Austenitic start temperature greater than the highest operating temperature of the application environment. In this configuration, applying a stress load, for example, during threading and knot formation, causes deformation as shown in FIG. 4 , wherein the deformation results in the application of a pinching force and a more secure relationship. More particularly, as the lashing material 12 is tightened, the Martensitic eyelets 14 deform by as much as 8% (local strain) and flatten around the lashings material 12 . When the tying force is released, the lashing material 12 is retained in the eyelets 14 due to the pinching force and frictional interaction. Heating the eyelets 14 to the Austenitic finish temperature causes them to revert to their memorized shapes shown in FIG. 4 ; in this condition, the eyelets 14 are dilated, such that the lashing material 12 can be withdrawn or threaded more easily. It is appreciated that the inventive methods of lashing described and illustrated herein may employ other formations of lacing, such as cross, bar, and lock lacing.
In yet another embodiment, the holding force in the secured relationship is increased by using an insert 26 (e.g., bead, ring, etc.) within the structure of the lashing material 12 ( FIG. 4 ). More preferably, a plurality of inserts 26 compose the material 12 , and longitudinally interconnect a plurality of non-active, durable sections 28 ( FIG. 4 ); or the sections 28 may also be active as previously described. The inserts 26 are configured to pass through each eyelet 14 in its dilated or widened shape but not its narrow form ( FIGS. 3-4 ). The inserts 26 are preferably spaced such that, once threaded, the lashing material 12 is further retained by their concurrent engagement with the eyelets 14 . As such, it is appreciated that the inserts 26 present a maximum cross-sectional diameter greater than, more preferably greater than 105%, and most preferably greater than 115% of the inside diameter defined by the eye 14 a . Where the eyelets 14 present fixed geometric shapes, the inserts 26 may be compressible (e.g., formed of elastomeric material or natural rubber, filled with a fluid gel, etc.) such that the actuation force of the active lashing material 12 is sufficient to pull the inserts 26 through the eyelets 14 . In this configuration, it is appreciated that the eyelets 14 serve as a holding mechanism that retains the secured relationship, when the active material element 16 is deactivated. The inserts 26 may present leading sloped faces to facilitate one-way travel, and/or ratcheting configurations where plural stroke lashing materials 12 are employed.
Alternatively, where the eyelets 14 present fixed geometric shapes, the inserts 26 may themselves be formed at least in part by an active material element 16 , such that their geometric shapes are actively modified or their ability to change shapes is actively modified. For example, as shown in FIG. 4 , the inserts 26 may each present a ring-like configuration, made of Austenitic SMA (or a baroplastic, SMP). In a normally wide geometric shape, each insert 26 is unable to pass through the associated eye 14 a ; but in the flattened or more narrow condition pass easily therethrough. The inserts 26 are preferably integrated into the lashing material 12 , such that the tensile tying/pulling load results in a stress-induced Austenite to Martensite transformation.
Where one-way SMA is used, the inserts 26 become more pliable in the Martensitic state, and are able to be manually flattened and pulled through the eyelets 14 during threading/withdrawing. Relaxing the pulling force causes a reverse transformation that causes the inserts 26 to revert back to their widened shape. It is appreciated that the assembly 10 may be configured such that potentially harmful cargo accelerations exert a stress upon the active inserts sufficient to cause their transformation and ability to pass through the eyelets 14 . This results in energy dissipation, the lashing material 12 providing increasingly more slack, and a passively and selectively actuated mode of operation. It is appreciated that the inserts 26 may comprise two-way SMA, such that transformation and reverse transformation results in automatic flattening and widening respectfully. Finally, it is also appreciated that an elastomeric core 30 may be incorporated within each insert 26 to provide a return bias towards the widened shape.
In FIG. 5 , the illustrated assembly 10 composes an athletic shoe 102 , and presents a preferred embodiment wherein the lashing material 12 and eyelets 14 comprise first and second active material elements 16 a,b , respectively. For example, the active material elements 16 a,b may be formed at least in part by shape memory alloy in a normally Martensitic state, and cooperatively configured such that the lashing material (lace) 12 is caused to shorten and reduce slack, and the eyelet 14 is caused to collapse and better retain a secure relationship, when the active material elements 16 a,b are activated. Activation may occur passively by solar radiation and heat, e.g., during jogging, or on-demand by exposing the elements 16 a,b to a heating source 18 after the shoe 102 is placed upon a foot. In a preferred embodiment, the active material elements 16 a,b are cooperatively configured such that the first element 16 a is caused to activate and modify the lashing material 12 prior to activation and modification of the second elements 16 b and eyelets 14 . As such, it is appreciated that the elements 16 a,b may be formed of SMA having differing constitutions, cross-sectional areas, or surface treatments (e.g., emissivity, etc.), so as to present different transformation temperature ranges. It is appreciated that the assembly 10 may be employed by other items of clothing and footwear, including but not limited to corsets, girdles, ice skates, snow skis, and boxing gloves.
This invention has been described with reference to exemplary embodiments; it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to a particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
Ranges disclosed herein are inclusive and combinable (e.g., ranges of “up to about 25 wt %, or, more specifically, about 5 wt % to about 20 wt %”, is inclusive of the endpoints and all intermediate values of the ranges of “about 5 wt % to about 25 wt %,” etc.). “Combination” is inclusive of blends, mixtures, alloys, reaction products, and the like. Furthermore, the terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The modifier “about” used in connection with a quantity is inclusive of the state value and has the meaning dictated by context, (e.g., includes the degree of error associated with measurement of the particular quantity). The suffix “(s)” as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the colorant(s) includes one or more colorants). Reference throughout the specification to “one embodiment”, “another embodiment”, “an embodiment”, and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments. | A securing assembly adapted for promoting a more secure relationship through active material actuation, facilitating lashing, attenuating tension, reducing slack, and/or facilitating unlashing, include selectively or passively modified lashing material and/or eyelets comprising active material elements. | 3 |
CROSS REFERENCE TO RELATED APPLICATION
The invention of this application is disclosed in corresponding International Application No. PCT/SE81/0027 filed Apr. 27, 1981, the benefit of which is being claimed.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a building structure of the type incorporating a framework consisting of vertical posts and base portions and head portions adapted to interconnect and keep the posts together and with separate wall sections fitted in the spaces between posts, base portions and head portions.
2. Description of the Prior Art
Building structures of this type are earlier known in a plurality of different embodiments which are more or less complicated in shape and handling. These older structures are often precisely adapted to a specific building purpose which means that they have almost no flexibility in the choice of building side and design.
BRIEF SUMMARY OF THE INVENTION
The present invention has for a purpose to provide a building structure of the type in question, which has a very great flexibility and which is very simple especially to mount and dismount without tools other than a common screw driver and this has been achieved mainly in that each post has an approximately H-shaped cross-section, in which each leg of the H-profile extends obliquely on its outer surface by froming each outer surface inclined obliquely. Each base portion and each head portion at its side turned to the center of the framework in a manner similar to the posts are provided with a groove located between material portions having surfaces inclined obliquely outwards. Flat, smooth wall elements and/or thin-walled panel sections along all edges are provided with flange portions bent in the same direction as the inclined surfaces of the posts, the base portions and the head portions, which flange portions at their outer ends are provided with folded material portions, the smooth wall elements being intended to be mounted with the edge portions engaging in the grooves in the base portions, in the head portions and in the space between the legs, of the the H-profile, whereas the panel sections are intended to be snapped with their flange portion to the inclined surfaces of the framework of the structure, and the folded material portions are adapted to snap into the grooves behind said inclined surfaces in the framework.
DESCRIPTION OF THE DRAWINGS
The invention will hereinafter be further described with reference to the accompanying drawings wherein;
FIG. 1 is a perspective view showing a portion of a building structure according to the invention with certain material portions omitted,
FIG. 2 is a cross-sectional view of a one-piece post forming part of the building structure according to the invention,
FIG. 3 is a similar view of a post consisting of a number of sheet metal sections,
FIGS. 4-6 are perspective views showing the sheet metal profiles forming parts of the post according to FIG. 3,
FIGS 7 and 8 are a perspective view and a top plan view respectively of a base portion and a head portion forming part of the building structure according to FIG. 1,
FIG. 9 is a schematic view from above of a corner connection incorporating two posts and corner profiles interconnecting said posts, FIGS. 10 and 11 are perspective views showing a corner profile according to FIG. 9,
FIG. 12 is a plan view of a panel section forming part of the structure, FIG. 13 is a schematic view from above of a base portion and a post fitted thereto in its mounting position, FIG. 14 is a view corresponding to FIG. 13, wherein for the sake of clarity the base portion has been omitted and in which a panel section has been mounted, whereas the other section is shown in its mounting stage, FIGS. 15 and 16 are croos-sectional views through the member shown in FIG. 13 taken along lines A--A and B--B, respectively, and FIG. 17 is a schematic view from above of three posts with different combinations of wall sections fitted thereto.
DETAILED DESCRIPTION
In FIG. 1 is shown in perspective a portion of a wall erected with the building structure according to the invention and as can be seen from this FIGURE the sturcture incorporates a plurality of vertical posts 1 having a mainly H-haped cross-section. The structure furthermore comprises a plurality of panel sections 2 mounted on the posts and a plurality of base portions 3 and head portions 4, which is basically the same component and the shape of which will be further described hereinafter. The structure also incorporates a corner connection 5, 6 intended for forming of wall corners and these components will also be further described hereinafter and are used or forming together with two posts a corner in the stucture. The FIGURE also shows how a wall in a simple manner can be built by means of the building structure according to the invention and for the sake of clarity parts of the head portions 4 have been cut away in the FIGURE.
In FIG. 2 is shown a cross-section of a post 1, which in this embodiment is made in one piece, e.g. by extrusion or the like. The post 1 has the shape of a H (in the FIGURE shown in laying position), the shanks or legs of which at their ends having inclined surfaces 7 which form and angle of 45° with the longitudinal direction of the legs. Between the inner side o the two legs and the cross bar or web there is thus formed two parallel grooves 8 running in the longitudinal direction of the post and intended together with the inclined surfaces 7 to contribute to the attachment of the panel sections such as will be further described hereinafter.
In FIG. 3 is shown an alternative embodiment of a post 1a, which is constructed from a number of sheet metal profiles in accordance with FIGS. 4-6, which in perspective show portions of the profiles forming part of the post.
The post 1a incorporates two profiles 9 according to FIG. 4, two profiles 10 according to FIG. 5 and two profiles 11 according to FIG. 6. In making this post the two mainly -shaped profiles 9 are located with the open sides against each other, whereupon the [-shaped profiles 10 with their double-flanged ends from the sides are fitted so that the four profiles together form a closed four-sided body having protruding portions-the shanks of the H-profile. The profiles 11 with the folded flange portions are thereupon each pushed from one of the ends of the post over to opposite projecting portions, whereby the profiles 11 will effectively interlock the separate sheet metal profiles to form a post without the need of any other type of attachment means. The profiles 11 are provided with inclined surfaces which form the inclined surfaces 7 of the post. This post 1a thereby has a shape quite analogous with the post 1 according to FIG. 2 with inclined surfaces 7 and grooves 8.
In FIGS. 7 and 8 are shown in a perspective view and in a plan view respectively a base portion 3 and a head portion 4. This base portion or head portion is formed by a mainly U-shaped chute preferably of sheet metal material in which the U-shanks 12 at their free ends have been bent inward/upward at an angle of 45° and these bent portions 13 are in turn at their free ends provided with flange portions 14 which extend in parallel with the U-shanks 12 a short distance towards the interior of the U-profile. In FIG. 8 is shown how the base portion or the head portion at equal mutual distances is provided with recesses 15 in the angular portions 13. These recesses or stampings are made at an angle of 45° relative to the longitudinal direction of the profile, whereby a recess 15 will correspond to the cross-section of the post 1, 1a. In the embodiment shown the profile 3, 4 has a centrally located recess 15, the cross section of which corresponds to the cross section of an entire post, whereas the profile at each of its two ends is provided with a half recess 15a, which corresponds to a half post. These base portions 3 are intended to act as bases for the posts and the posts are placed in upright position in the chute which is formed by the bottom and walls 12 of the base portion in said recesses 15, 15a, whereupon the base portions and the posts are interconnected preferably by means of self-tapping screws. The head portions 4 which are identically similar to the base portions are located in corresponding manner on top of the posts and they are connected thereto in the same manner. By means of this connection the posts and the base portions/head portions will form a continuous framework after mounting.
In order to form a corner in the structur two posts 1 are as shown from above in FIG. 9 placed side by side with their grooves 8 turned perpendiculary to each other and with two inclined post surfaces 7 contacting each other. An interconnecting corner profile 6--see FIG. 11--is fitted e.g. by means of self-tapping screws to the two adjacent posts, whereby also these will be connected. The corner is therupon finished thereby that a corner profile 5--see FIG. 10--is fitted to the posts. This corner profile 5 has a cross section corresponding to an isosceles right angle triangle, in which the hypotenuse is broken and formed with two lugs 16, which extend out from the triangle in parallel with the adjacent smaller side of the triangle. The corner profile 5, which is made from sheet metal is connected to the post by being pushed from the outside inward against the posts, whereby its lugs 16 during bending will slide on the inclined surfaces 7 of the posts and will snap into the grooves 8, whereby they will flex back and be locked in their position. At this mounting of a corner it is possible with a finebladed tool to enter between the inclined surface 7 of the post and the part of the corner profile 5 cooperating therewith and therby to press the lug 16 from its engagement with the edge of the groove 8.
In FIG. 12 is shown in a plan view a panel section 2 from the side turned inwards during mounting. The opposite side is as can be seen from FIG. 1 preferably entirely smooth. The panels can however also be provided with reinforcing bendings or the like without this being critical for the invention. The panel section 2 is along its inner edges bent in a first flange 17 at an angle of 45° and a second bent flange 18 is provided at the outer end of said first flange, which second flange is likewise bent 45° and in a direction outwards. These flanges corresond to the lugs at the corner profile 5 and they are used in a corresponding manner for locking the panel sections to the base portions, to the posts and to the head portions.
In FIG. 13 is shown in a view from above a part of a base portion 3 with a post 1 fitted and screwed thereto and this view shows how the post 1 with its inclined surfaces 7 will be guided by the inclined recesses 15 in the base portion. In this FIGURE is also shown a panel section 2, which with one of its edge flanges rests against and which has been snapped to the bent parts 13 of a base portion and to its flange portion 14, respectively, whereas the adjacent edge flanges 17, 18 have been snapped into the groove 8 and rest against the inclined surface 7 of the post.
In FIG. 14 is shown the snapping-in of a panel section 2 to a post 1 in which for the sake of clarity the base portion has not been shown and the panel section 2 is hereby subjected to a manual force directed inwards, whereby all flange portions 17 and 18 simultaneously or one after the other will be brought to flex out and slide against the inclined surface 7 of the post and against the inclined portions 13 of the base portion and the head portion respectively until the second bent flange 18 will be in position to snap into the groove 8 and behind the flange portions 14 of the base portion and the head portion respectively.
In FIGS. 15 and 16 there are shown two cross-sections along lines A--A and B--B in FIG. 14 respectively which illustrate the cooperation of the panel sections 2 with the base portion 3, which cooperation functionally is analogus with the cooperation with the post.
FIG. 17 finally shows in a schematic view from above the possibility of the building structure according to the invention to use different types of wall sections which can be utilized for further increasing the flexibility and adaptability of the structure.
In this figure is shown as an example three spaced apart posts 1 placed in a line. To the right hand side of a post shown farthest to the right is fitted two panel sections 2, which are fitted by snapping-in in the same manner as shown in e.g. figure 13. Between the left and the central post there is however fitted a smooth flat wall element 19, which with its edges engages in and is retained in the grooves 8 between the shanks of the H-profile of the posts (and also in the grooves in the not shown base portions and head portions). In the space between the central and the right hand post is finally shown how it is possible to combine a snapped-in panel section 2 and a wall element 19.
The wall element 19 can be of different types and it is e.g. possible to use wall-paper provided particle boards, plaster boards or the like, window units in frames etc., whereby the inclined surfaces of the posts, the base portions and the head portions can be coloured in a suitable tint and can then act as surrounding borders. As it is possible also to make the wall sections with different material at opposite sides it is e.g. possible to have a board wall at one side made with plane wall elements and on the opposite side an "outer wall" of panel sections, which have been snapped to the framework.
In the case of wall elements 19 fitted in the grooves it is of course necessary to mount the wall elements in a manner which differs from that of the snappable wall panels, i.e. it is necessary to place the wall element 19 in the framework before this is completed, whereby the wall can be completed and locked by means of one of the posts, which hereby is put in place by being moved in the longitudinal direction of the wall element. The mounting is however also in this case comparatively simple and so is also a possible later dismounting.
With this mounting technique it is possible to erect buildings of this type very swiftly and also to dismount them as it is hereby sufficient to unscrew the screws retaining the head portion and the base portion and to pull out these parts in the longitudinal direction from the remaining structure, whereupon the further components--the wall elements, the panel sections and the posts--can be easily taken apart. With this building structure it is possible either to standardize the elements forming part thereof to a very high degree or to adapt the portions to the actual need, e.g. by changing the width of the sections, varying the height of the base portions or the head portions, designing the sections as holders for lamp fittings, armatures, exhaust suction filters etc, which means that the structure will have a very high flexibility. It is also possible to provide the building with doors made in a corresponding manner and to arrange insulating material in the post and/or between the panel sections. It is also possible to design the panel section of another material than sheet metal, e.g. in wood with flexible attachment flanges fitted thereto or to make the entire structure or parts thereof in another material which is equivalent from a material point of view, e.g. some plastic types.
The invention is not limited to the embodiments shown in the drawings and described in connection thereto but modifications are possible within the scope of the appended claims. | A building structure comprising a plurality of post (1) designed with a mainly H-shaped cross section and arranged to be located in upright position in a chute-formed base portion (3) and panel sections (2) adapted to be fitted to the posts and the base portion. The posts (1) and the base portion are provided with surfaces (7, 13) inclined at an angle of 45°, the panel sections (2) are provided with first flanges (17) bent in a corresponding manner and adapted after the mounting to engage against said inclined surfaces (7, 13) and during mounting when they are bent aside to slide against the inclined surfaces of the post and the base portion in order to locate a locking member (18) provided at the outer end of the flanges to engagement behind said inclined surfaces. | 4 |
This application is a continuation of international application serial number PCT/EP99/09177, filed Nov. 24, 1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an architecture, for a transmitter in a mobile communications system and particularly, but not exclusively, to an architecture for a base-station transmitter which supports frequency-hopping in a TDMA environment.
2. Description of the Related Art
At present in Europe a GSM standard operates for transmission of information in the mobile communication network. According to that standard, information is transmitted in a sequence of time slots, each time slot having the possibility of being allocated a different carrier frequency for modulating the information to be transmitted. The GSM standard requires that transmitters in base station transceivers can switch their frequency (frequency-hop) between consecutive time slots. This has been achieved according to a known transmitter architecture by providing a so-called “ping-pong” synthesizer which generates different frequencies on a time slot basis. While this technique works, it requires high isolation between the synthesizers which is difficult to achieve.
BRIEF SUMMARY OF THE INVENTION
According to the present invention there is provided a transmitter for transmitting RF data in an RF communication network using a plurality of carrier frequencies, the transmitter comprising:
a data splitter for receiving an information signal at an intermediate frequency lower than the carrier frequency; and two transmitter paths each having an input connected to the data splitter and each having a frequency modulator for upconverting the intermediate frequency to a respective carrier frequency, the carrier frequency being individually selectable for each transmitter path.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention and to show how the same may be carried into effect the invention will now he described, by way of example only, with reference to the accompanying drawings in which:
FIG. 1 is a block diagram showing the principle components of a known transmitter system used in a base-station;
FIG. 2 is a block diagram showing a number of separate transmitter paths in the transmitter;
FIG. 3 illustrates part of a signal transmitted by one of the transmitter paths;
FIG. 4 illustrates the format of a signal transmitted by the transmitter as a whole;
FIG. 5 illustrates the construction of a time slot;
FIG. 6 is a block diagram illustrating a known frequency hopping control in a transmitter path;
FIG. 7 is a block diagram showing the components of a transmitter path according to the present invention; and
FIG. 8 is a timing diagram of a time slot in a transmission signal generated by a transmission path.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram of a transmission system 10 for an RF communications system such as that for a mobile telephone network. Such a transmission system may be utilised, for example, at a base-station for the communications network or within mobile stations communicating with the base-station.
A data input signal DATA, which may be in analog format, is supplied to the system from a data generator (not shown). The input signal may contain voice information or any other such information which is required to be transmitted. The input signal is fed into a data interface 2 which performs the necessary encoding etc. to generate an information signal 1 for transmission. The precise details depend on the nature of the communications system.
The information signal 1 is supplied to a mixer 3 to which there is also supplied an intermediate frequency signal generated by an I.F. generator 4 . The mixer 3 mixes the two signals such that the output therefrom is an intermediate frequency signal i.f modulated by the information signal. In essence, therefore, the information signal is up-converted from the base-band to an intermediate frequency.
The up converted information signal i.f. is then amplified by an amplifier 5 and is supplied to a second mixer 6 .
A local oscillator 7 generates a radio frequency carrier signal f c which is fed into the second mixer 6 . The carrier frequency fc is selectable by a controller 8 within a transmission band which may lie, for example, between 935.2 MHz and 9598 MHz. The information signal i.f and the carrier signal f c are mixed and output as a transmission signal TX. The transmission signal thus comprises the carrier signal f c modulated by the information signal i.f. Again, in essence the information signal is further up-converted to radio frequencies to facilitate transmission.
A pre-amplifiers 9 amplifies the transmission signal to a level to enable the signal to be transmitted via land line to an antenna station 11 , which may be situated remote from the base station 10 , without the signal being attenuated to such an extent that it becomes unusable. Such an antenna station may comprise an antenna and a power amplifier which amplifies the transmission signal to levels which allow the signal to be transmitted as electromagnetic radiation over large distances.
Once amplified by the power amplifier, the transmission signal is fed to the antenna as an output signal from where it is radiated out as electromagnetic radiation.
Usually, of course, such a transmitter is required to be capable of transmitting to more than one mobile unit simultaneously. To achieve this, a base station transmitter is able to transmit many signals simultaneously at different frequencies. The total bandwidth allocated to the communications network is divided into discrete carrier frequencies (124 in GSM) at 200 KHz intervals. In order to generate these different frequencies, the base-station transmitter further comprises a number of so-called transmitter paths T 1 etc. as shown in FIG. 2 . Each of the transmission paths in FIG. 2 has the components of the transmitter 10 in FIG. 1 . Each transmitter path is capable or generating signals at frequencies different to the other transmitter paths. Furthermore, each transmitter path can usually vary its transmission frequency such that it can generate signals at all of the discrete carrier frequencies if required.
As is known in the art, a TDMA system provides for a particular mobile unit to have access to a particular transmission frequency for a limited period of time (a time slot), so that a communication channel is established by reference to a particular times slot.
The signal transmitted by the transmitter path is of a form generally illustrated by FIG. 3 . The signal consists of a sequence of frames (A, B, C. . . ). Each frame is sub-divided into 8 time periods called time-slots (0-7).
Each time slot (0-7) contains data for one mobile unit. Subsequent data for that mobile unit will, under typical circumstances, be sent in the same time slot in subsequent frames. Thus, time slot 0 in frame A may contain data for mobile G unit MB 0 . Time slot 0 in frame B will then also contain data for mobile unit MB 0 , as will time slot 0 in frames C, D, E . . . etc. This allocation of time slot 0 to mobile unit MB 0 may continue until such time as the connection to mobile unit MB 0 is terminated. The internal clocks of the base station and the mobile unit MB 0 are synchronised such that the mobile unit MB 0 always and only listens for data during time slot 0 of any frame. In other words, the communication channel between the base station and the mobile unit MB 0 are only “open” during its allocated time slot. Similar considerations apply to communication channels with mobile units allocated to other time slots.
FIG. 4 illustrates conceptually the structure of data transmitted by the base station transmitter. The transmitter path T 1 has allocated to it the Channel group 1 comprising 8 mobile units MB 0 -MB 7 . It transmits a signal made up of a sequence of frames (A, B, C . . . ) each frame being divided into 8 time slots ( 0 - 7 ) containing data for one of the 8 mobile units. The transmitter path T 2 has allocated to it the Channel Group 2 comprising a further 8 mobile units MB 8 -MB 15 . It transmits a signal (simultaneously but on a different frequency to that of the transmitter path T 1 ) made up of a sequence of frames A, B, C . . . but with each time slot ( 0 - 7 ) containing data for one of its own mobile units MB 8 -MB 15 .
As described above, the base station transmitter may be made up of a large number of transmitter paths, some or all of which (depending on the volume of “traffic”) may be transmitting signals simultaneously on different frequencies.
The data contained in each time slot is usually made up of several parts as shown in FIG. 5 . The data may comprise:
TAIL BITS (TB)—two groups of 3 bits for control/reset purposes, ENCRYPTED BITS—two groups of 58 bits represented transmitted data, TRAINING SEQUENCE—a fixed bit pattern of 26 bits used in generating a channel response,
GP denotes the guard space (of 8.25 bits, 30.46 μs in described example) to allow for time/distance propagation delays owing to cell size.
FIG. 8 shows a timing diagram of a signal transmitted by a single transmitter path. Each time slot has a time span of 577 μis in the described example. Within each time slot the transmitted signal is firstly “ramped up” to a specified level during the first 28 μs of the time slot. Then the data is transmitted at that level over the following 542.8 μs (147 bits). Finally, the signal is “ramped down” over the subsequent 28 μs. The following time slot is transmitted in a similar way.
Part of the GSM requirements are that the communications system must be capable of frequency -hopping. As the name implies, frequency-hopping is the ability to change the transmit frequency of any particular channel at regular intervals. Such frequency-hopping is primarily used to provide a level of security for transmitted signals and to prevent unauthorised parties from “eavesdropping” on mobile telephone transmissions.
Frequency hopping may occur between consecutive frames or consecutive time slots. In any event, a frequency change needs to be effected between time slot 7 of frame A and time slot 0 of Frame B.
Referring back to FIGS. 2 and 3 , each transmitter path is capable of transmitting signals at different frequencies. In order to provide frequency-hopping, the transmitter path changes the frequency at which it transmits after each time slot. Thus, time slot 0 in frame A may be transmitted by transmitter path T 1 at a frequency f 0 . Time slot 1 of frame A may then be transmitted at a frequency f 1 . Similarly, time slot 2 in frame A may be transmitted at a frequency f 2 and so on. Time slot 0 of frame B may subsequently be transmitted at a frequency f n where n is a number other than (in this case) O, i.e. the frequency at which time slot 0 is transmitted in any frame must be different from the frequency at which it was transmitted in the previous frame.
The manner in which the frequencies of each time slot vary is specified in GSM and is determined by an algorithm and controlled by a frequency controller. The varying of the frequencies at which data for a single mobile unit is transmitted ensures that it becomes very difficult for any unauthorised receiver to lock onto the correct signal in order to eavesdrop.
FIG. 6 shows a system which provides frequency-hopping in a base station transmitter. As illustrated, the components within the box T 1 represent the transmitter path T 1 shown in FIG. 2 .
Each transmitter path comprises a data input into which is fed a data signal DATA containing data to be transmitted (e.g. speech). The data signal, which may be in an analog form, is then sent through a data interface 50 which may be represented by an analog to digital convertor, which encodes the signal such that it is suitable for transmission. The data interface 50 outputs the signal as the information signal i.
As described with reference to FIG. 1 , the information signal i is mixed with an intermediate frequency signal f i generated by an I.F generator 52 (up converted) to produce information signal i.f. and then amplified by an amplifier AMP 2 .
In order to provide hopping between different transmission frequencies, each transmission path is provided with two local oscillators or synthesizers (S 1 , S 2 ) which are variable in frequency, The two synthesizers S 1 and S 2 are operable to generate radio frequency carrier signals which are mixed with the information signal i by mixer M 3 before transmission.
The outputs of the synthesizers are input to a switch SW 1 which provides for the connection of either S 1 or S 2 (but not both simultaneously) to the mixer M 3 in a so-called ping-pong arrangement. An attenuator A 0 is connected downstream of the mixer M 3 and upstream of a filter F 0 .
In operation, when transmitter path T 1 (for example) is transmitting time slot 0 in frame A, synthesizer S 1 generates a carrier signal C 0 at a frequency f 0 . Switch SW 1 , under the control of a timing control unit TC 1 , switches to allow S 1 to be connected to mixer M 3 . In this manner, the information signal i.f. (containing data for a particular mobile unit) is mixed with the carrier signal C 0 to produce the transmission signal TX 0 associated with time slot 0 in frame A.
At the same time, the synthesizer S 2 tunes itself to a different frequency f 1 to be used for transmitting time slot 1 in frame A. As described above, the frequency to which S 2 tunes is determined by an algorithm in conjunction with the frequency control unit FC.
After transmitting the data in time slot 0 , the timing control unit TC 1 then switches to allow the synthesizer S 2 , generating a carrier signal C 1 at frequency f 1 , to be connected to the mixer M 3 . The information signal i.f (now containing information to be transmitted to a different mobile unit) is mixed with the carrier signal C 1 to produce the transmission signal TX 1 associated with time slot 1 .
Once again, during the period in which synthesizer S 2 is connected to the mixer via switch SW, synthesizer S 1 tunes itself to a different frequency f 2 to be used for transmitting time slot 2 in frame A, determined by an algorithm in conjunction with frequency control unit FC.
This process is repeated for subsequent time slots and subsequent frames.
A major problem with the architecture employed by systems such as those of FIG. 6 is that the switch SW 1 must provide a very high degree of isolation between synthesizers S 1 and S 2 . If, within the switch, the connections from S 1 and S 2 are not sufficiently isolated, then interference and phase distortion will occur between the two signals. This interference corrupts the transmission signal. In practice, isolation between the connections of S 1 and S 2 must be provided to a level of around 90 dB in order to prevent these problems.
Switches which provide this level of isolation are complex and expensive.
FIG. 7 shows an architecture for a transmitter path which aims to address this problem.
A data input is connected to a data interface. This interface may be an analog to digital convertor operable to perform a suitable encoding process and has an output to a mixer M 0 . The output of mixer M 0 is connected to a data splitter or switch DS which itself is connected to a timing control unit TC 2 . The Data splitter DS has two outputs, the lines L 1 and L 2 .
The line L 1 is connected to a first mixer M 1 . The first mixer M 1 is connected to the synthesizer S 1 and is operable to mix the information signal on the line L 1 with a carrier signal generated by the synthesizer S 1 .
The output of the first mixer M 1 is connected to an attenuator A 1 , the output of which is connected to an amplifier AMP 1 . The output of the amplifier AMP 1 is connected to a second attenuator A 2 , the output of which is connected to a power combiner PC.
The Line L 2 is connected to a second mixer M 2 . The second mixer M 2 is connected to the synthesizer S 2 and is operable to mix the information signal on the line L 2 with a carrier signal generated by the synthesizer S 2 .
The output of the mixer M 2 is connected to an attenuator A 3 , the output of which is connected to an amplifier AMP 2 . The output of the amplifier AMP 2 is connected to a second attenuator A 4 , the output of which is connected to the power combiner PC.
The output of the power combiner PC represents the transmission signal which is to be transmitted.
Synthesizers S 1 and S 2 are each connected to a frequency control unit FC. Although in FIG. 8 the frequency control units connected to the synthesizers S 1 and S 2 are shown as separate components, they may be provided as a single unit as in FIG. 7 .
The attenuators A 1 -A 4 are each connected to a power control unit PC 1 .
In operation, data to be transmitted is input to the data interface in a similar manner to the system described above. The data interface performs a suitable encoding process on the data and outputs the data as an information signal i. The information signal is fed to the mixer M 0 which mixes it with an intermediate frequency signal f i generated by an intermediate frequency generator G 1 . The up converted information signal i.f is then fed to the data splitter DS which supplies the information signal to lines L 1 and L 2 . It may be advantageous to switch the information signal such that it is output either on the line L 1 or the line L 2 under control of the timing control unit TC 2 .
If the transmitter path T 1 (for example) is to transmit time slot 0 in frame A, the synthesizer S 1 generates an RP carrier signal C 0 at a frequency f 0 . The information signal is output on the line L 1 to the first mixer M 1 . In this manner, the information signal is mixed with the carrier signal C 0 to produce the transmission signal TX 0 associated with time slot 0 . The transmission signal TX 0 is passed through the attenuators A 1 and A 2 and the amplifier AMPl to the power combiner PC. The power combiner PC outputs the transmission signal as the signal to be transmitted in time slot 0 .
Simultaneously, the frequency control unit FC sends a signal to the synthesizer S 2 to tune itself to generate an RF carrier signal C 1 at a different frequency f 1 to be used for transmitting time slot 1 in frame A. As in the conventional system, the frequency to which the synthesizer S 2 tunes is determined by an algorithm in conjunction with the frequency control unit FC. Also at this time, the power control unit PC 1 controls the attenuators A 3 and A 4 such that any signal being generated by synthesizer S 2 are attenuated to a low level at the input to the power combiner PC compared to those signals generated by the synthesizer S 1 .
After transmitting the data in time slot 0 , the transmitter path T 2 can be used to transmit time slot 1 . The data splitter outputs the information signal, containing information to be transmitted in time slot 1 , on line L 2 to the mixer M 2 . In this manner, the information signal is mixed with the carrier signal C 1 generated by the synthesizer S 2 at a frequency f 1 to produce the transmission signal TX 1 associated with time slot 1 .
During the period in which time slot 1 is being transmitted, the synthesizer frequency control FC sends a signal to the synthesizer S 1 to tune itself to a different frequency f 2 . As before, the frequency to which the synthesizer S 1 tunes itself is determined by an algorithm. Also during this period, the power control unit PC 1 controls the attenuators A 1 and A 2 such that any signals being generated by the synthesizer S 1 are attenuated to a low level when they reach the power combiner PC compared to the signals which are generated by the synthesizer S 2 .
This process is repeated for subsequent time slots and subsequent frames.
It can be seen that in the above described embodiment an advantage resides in providing two separate branches within each transmitter path along which to transmit the information signal. With such an architecture, the carrier signals generated by the synthesizers S 1 and S 2 only come into close proximity with each other in the power combiner PC. At this point, however, at least one of the signals is attenuated to a low level compared with the other such that interference between the two signals in low. The power combiner, therefore, needs only to provide a low level of isolation within the power combiner which can be achieved easily and inexpensively.
The second transmitter path branch replaces the expensive switches which are normally needed to provide isolation. In addition to providing inherent isolation between the synthesizers, the architecture also provides simplified power control. Each branch of the transmitter path operates on alternate time slots. This allows for the full use of the guard periods for ramp up and ramp down used in the transmitter.
Furthermore, the second branch provides a higher level of redundancy, and hence reliability, for each transmitter path. The architecture itself is suitable for integration to an Application Specific Integrated Circuit (ASIC). In this regard, it may be possible to incorporate this structure into the ASICs currently used in mobile units. | A transmitter for transmitting RF data in an RF communication network using a plurality of carrier frequencies is described. The transmitter has a data splitter for receiving an information signal at an intermediate frequency lower than the carrier frequency, and two transmitter paths each having an input connected to the data splitter and each having a frequency modulator for upconverting the intermediate frequency to a respective carrier frequency, the carrier frequency being individually selectable for each transmitter path. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of Ser. No. 403,941, filed Oct. 5, 1973, now abandoned.
BACKGROUND OF THE INVENTION
There is a known device which supplies liquid, such as ink, in the form of a succession of drops to a printing apparatus, for example a dot-matrix printer. The known device has an outer and inner chamber interconnected through an inner capillary opening. The inner chamber has a wall which is formed by a diaphragm that is moved by means of the oscillations of a piezoelectric crystal. The diaphragm is arranged to curve inwardly toward the inner chamber and cause a pressure increase therein. Fluid, for example ink, from the inner chamber will then be ejected at a substantial velocity through the inner capillary and then into the outer chamber. The latter contains a thin liquid layer communicating with an ink reservoir. A thin wall represents the outer wall of the outer chamber against the medium on which the print is to be applied. The thin wall is provided with an outlet capillary located opposite to the inner capillary. In this arrangement, a liquid plug is ejected from the inner capillary which strikes the outlet capillary expelling the liquid therein in the form of a liquid drop. This release of the printing ink liquid in the form of drops continues until the voltage on the piezoelectric crystal is removed and the diaphragm returns to a normal position. A negative pressure is then created in the inner chamber which is transferred to the outer chamber by means of the inner capillary. The pressure is equalized by means of liquid being drawn in from a reservoir communicating with the outer liquid layer or by the liquid column in the outlet capillary being drawn back against the action of the capillary force. Since the resistance of the liquid layer in the outer chamber is considerably smaller than the resistance emanating from the capillary force, the liquid required to equalize the pressure will flow from the aforesaid liquid layer. Thus, the known device operates like a pump by drawing liquid in from the outer chamber and forcing the liquid out through the outlet capillary.
It should be pointed out that the prior art device has a number of disadvantages. For example, the closed inner chamber can be filled with liquid only by drawing a large vacuum on the entire system which causes a liquid reservoir of atmospheric pressure to be connected to said inner chamber. Inasmuch as it is not possible to achieve an absolute vacuum, a certain quantity of air in the form of an air cushion will remain in the inner chamber. When the diaphragm is acted upon, this air cushion will be compressed along with the liquid resulting in the reduced efficiency of the device. This occurs because the reduction of volume caused by the movement of the diaphragm is so small that even a small quantity of air causes a reduction of the volume of the air cushion instead of causing such a pressure increase as would have occurred in an incompressible medium. Another disadvantage of the prior art construction is that both the inner and outer chambers of the device are bounded by thin walls which are difficult to stabilize to prevent vibration during pressure changes in the chambers. The wall thickness is determined by the length of the capillaries which is in the order of 0.1 mm. Because of the small length of the capillaries there is a great risk of air being drawn into the system. Furthermore, because the length and width of each capillary as well as the thickness of the outer liquid layer are approximately 0.1 mm, the fabrication of the known device is complicated and expensive. Still another disadvantage of the known device is that the holes in the device must be centered absolutely opposite to each other along a straight line. As a result, the manufacturing tolerance requirements are extremely great when boring the holes and the mounting of the front wall of the device.
The present invention relates to an ink printer of the jet type in which liquid from one or more pump chambers is conducted to one or more outlet channels.
It is an object of the present invention to provide an ink printer supply arrangement which is simple and inexpensive to manufacture and assemble.
Another object of the present invention is to provide an ink supply and pumping arrangement having two opposite plates in which one plate has pumping means disposed in holes or recesses and the second plate has grooves at the surface thereof which faces the other plate. The pumping chambers are formed by the spaces between the pumping means and the second plate. Furthermore, the spaces communicate with the outlet channels.
The invention will now be more fully described with reference to the accompanying drawings, in which:
FIG. 1 is a top plan view of the plate constituting a crystal holder with mounted crystals and associated diaphragms, constructed in accordance with the teachings of the present invention;
FIG. 2 is a cross sectional view of the crystal holder taken along the lines II--II of FIG. 1;
FIG. 3 is a top plan view of an intermediate plate of the present construction;
FIG. 4 is a cross sectional view taken along the lines IV--IV of FIG. 3;
FIG. 5 is a top elevational view of the plate in the present construction provided with channels;
FIG. 6 is a cross sectional view taken along the lines VI--VI of FIG. 5;
FIG. 7 is a sectional view of the assembled printing head of the invention showing certain details of construction illustrated in FIGS. 1-6;
FIG. 8 is a cross sectional view of a printing head similar to that shown in FIG. 7 in which the plate with the channels is provided with an ink supply channel;
FIG. 9 is a cross sectional view of a printing head similar to that shown in FIG. 7 but in which the channeled plate is provided with an ink supply;
FIG. 10 is another embodiment showing a cross sectional view of the printing head;
FIGS. 11 and 12 are top plan views showing two crystal holders in another embodiment of the printing head;
FIG. 13 is a top plan view of a channeled plate;
FIG. 14 is a cross sectional view taken along the lines XIV--XIV of FIG. 13 on a reduced scale;
FIG. 15 shows an alternative embodiment of the printing head shown in FIGS. 11-13 but on a reduced scale;
FIG. 16 is a top plan view of a still further embodiment of the printing head; and
FIG. 17 is a cross sectional view of the printing head illustrated in FIG. 16.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, a plate 10 is shown which is constituted of nickel, stainless steel, or other suitable material that is generally unaffected by commonly used types of ink and forms part of the printing head. The plate 10 is provided with holes 11 which correspond in number to the number of channels in the printing head. Frequently, seven channels are used by the aid of which characters are formed in a matrix comprising seven by five dots. The holes 11 communicate through annular ledges 12 with corresponding holes 13 of larger diameter. A multiplicity of pumping means having the form of circular diaphragms 14 and preferably fabricated of the same material as the plate 10 are supported on the ledges 12 of the plate 10. The diaphragms are secured to the ledges, for example, by a suitable adhesive or by solder. A piezoelectric crystal 15 is mounted on the upper surface of each diaphragm 14. In the present arrangement, as is known, each crystal 15 is provided with a metallization on opposite flat surfaces forming electrodes to which suitable operating voltages can be connected. The lower electrode is connected to the diaphragm and the upper electrode is electrically connected to a connection conduit 16. Each of the diaphragms 14 is relatively thin so that a gap in a cylindrical shape is formed between the diaphragm and the underside of the plate 10 which functions as a pump chamber 17.
As seen in FIG. 1, the plate 10 is provided with holes 18 for centering of several superposed plates by means of guide pins (not shown). Furthermore, the plate 10 has additional holes 19 for screws or other fastening devices by means of which several superposed plates can be assembled to form a printing head.
Referring to FIGS. 3 and 4, an intermediate plate 20 is shown having spaced through holes 21 that are co-axial with the pump chambers 17, each of which has a considerably smaller diameter than each of the pump chambers. It should also be noted that the plate 20 has through holes 22 and 23 which correspond to the holes 18 and 19 in the plate 10. Furthermore, a shallow groove appears in the under-surface of the plate 20 constituting a widened portion 24 and a narrower portion 25. As seen in FIG. 3, the portion 25 of the shallow groove is close to the edge 26 of the plate 20 and forms a channel through which ink can be conveyed to the capillaries of the printing head.
A plate 27 is shown in FIGS. 5 and 6 having a plurality of shallow channels 28. Each channel terminates in a circular portion 29 which is generally concentric to the corresponding hole 21 in the intermediate plate 20. The channels 28 are shown to narrow down from the circular portions 29 to the edge 30 of plate 27 in which they open into the capillary nozzles 31. The length of each of these nozzles is preferably about 0.5 mm and the cross sections thereof are approximately 0.01 mm 2 . These dimensions, however, can be varied to suit the requirement of each particular construction. In addition, the capillaries may be either rectangular or circular in cross section.
As seen in FIG. 5, the plate 27 is provided with holes 32 and 33 corresponding to the holes 18 and 19 in the plate 10. Furthermore, a hole 34 communicates with an ink supply tube 35 (FIG. 6) which corresponds to the grooved portion 24 of the plate 20.
The intermediate plate 20 and/or the plate 27 having channels may be moulded of a suitable plastic or other material whereby grooves are made in the plastic to form required channels when the printing head is assembled. These grooves may be formed by etching or by stamping the plates. The capillaries also can be made either by the above-mentioned methods or may be bored when the head is in the assembled condition. If the capillaries are fabricated by boring the plate, the channels 28 must terminate, for instance 0.5 mm from the edge 30. Then the capillaries are bored from the edge 30 to the channels. The boring accuracy is not of great importance if the channels 28 are made deeper and wider than the capillaries.
Referring now to FIG. 7, a printing head is shown in cross sectional view having the details of construction illustrated in FIGS. 1-6. The precise relative position of of the superposed plates 10, 20, and 27 is determined by the aligned guiding holes 18, 22, and 32. These holes are provided with guiding pins (not shown) which accurately fit therein. The plates 10, 20, and 27 are assembled in a fixed relationship by means of screws (not shown) passing through aligned holes 19, 23, and 33. The abutting surfaces of the plates are so accurately planed that generally no special seal is required therebetween.
When the present printing head is used, all the channels in the device must be filled with ink. Therefore, the parts of the device can be assembled beneath the surface of a suitable liquid, such as glycerine. The assembly, in this case, can be accomplished under the liquid surface by tightening screws, and adsorbed air can be removed, for instance, by ultrasonic techniques.
When the printing head of the present invention is put into use, it is connected to an ink reservoir that is located in a plane lower than the nozzles 31 (FIG. 6). However, the nozzles will have printing liquid therein at all times because of the capillary force therein, which also acts to prevent the "bleeding" of the capillaries.
FIG. 8 shows an alternate construction of the present invention in which the plate 27 having the channels 28 is provided with an additional channel 36 that is located opposite to the channel 25 in abutting intermediate plate 20. This construction improves the liquid ink supply and the risk of air being drawn through the nozzles 31 is considerably reduced.
In FIG. 9, the ink supply channels 28 and 36 are shown to be solely in the plate 27. This construction permits the elimination of the intermediate plate 20, as is seen in FIG. 10. It should be noted that there are no holes 21, as seen in FIGS. 3 and 4, in the present construction and therefore, the entire diaphragm 14 will act on the corresponding part of the channels in the plate 27. Further in connection with FIG. 10, the piezoelectric crystals 15 are spaced apart more than the spacing illustrated in FIG. 1 in order to prevent the diaphragm from acting on an adjacent channel. Thus, the planar plate surface is larger and the channels are made longer.
Referring to FIGS. 11-14, another embodiment is shown in which the piezoelectric crystals 15 are mounted on two separate plates 37 and 38. In a printing head having seven channels, the plate 37 has four piezoelectric crystals 15, while the plate 38 has three crystals, all with associated diaphragms 14. The diaphragms on the plate 37 co-act with channels 39 in the channeled plate 40 shown in FIG. 13. It will be noted that the channels 39 are spaced apart a relatively large distance, thereby avoiding the possibility of one channel being acted upon affecting an adjacent channel. The diaphragms 14 on the plate 38 co-act in the same manner with channels 41 on the other side of channeled plate 40, as seen in FIG. 13.
FIG. 14 discloses the capillary nozzles 42 and 43 located on opposite sides of the channeled plate 40 in a staggered relationship. If the nozzles are positioned in a zig-zag pattern, they can be placed such that their projections on a longitudinal line will lie closer than can be achieved with a single row of nozzles. The capillaries shown in FIG. 14 may be so placed that all the nozzles are situated on a straight line. In the use of an ink jet printer where the printing head is moved along a line for printing purposes, the pulses delivered to the piezoelectric crystals can be retarded to certain crystals in order to compensate for the displacement of the printing head. FIG. 15 shows a construction in which the channels are made deeper than half the thickness of the channeled plate, at least near the marginal edge 44 of the plate 40. However, the channels must not abut the edge 44, but there must be a wall of suitable thickness between the end of the channels and the adjacent edge 44. As seen in FIG. 15, holes 45 are bored through the walls to the channels, and all of the holes may be located in a relatively straight line.
It will be noted that FIG. 13 does not show a channel corresponding to the channel 36 illustrated in FIGS. 8 and 10. However, in a printing head constructed in accordance with the teachings of the present invention, ink can be transported to the capillaries in a manner as illustrated in FIGS. 16 and 17. As seen in FIGS. 16 and 17, a channeled plate 46 is provided with channels 47 in one surface and channels 48 in the opposite surface of the plate 46. The channels open into respective capillary nozzles 49 and 50. The plate 46 also has ink supply channels 51 and 52 which is supplied with ink at inlets 53 and 54, respectively.
Referring again to FIG. 16, the channels 47 and 48 are illustrated as straight narrow grooves, but the channels may be constructed as shown in FIG. 13. The location of the crystals 15 and the diaphragms 14, as well as the other details of construction, may correspond to what is shown in FIGS. 11-15. FIG. 17 shows as assembled printing head in which the pumping means comprises a crystal 15 and a diaphragm 14 in each of the plates 10. As seen in FIG. 17, the channels 47 and 48 communicate with the channels 51 and 52, respectively, through the cylindrical gaps forming the pump chambers 17. | An arrangement for supplying liquid, such as ink, from at least one pump chamber to at least one outlet channel. The arrangement has at least two opposite plates in which one plate is provided with pumping means disposed in holes, while the other plate has grooves at the surface thereof facing said one plate. The arrangement is inexpensive to manufacture and simple to assemble, yet functions in a reliable manner. | 1 |
FIELD OF THE INVENTION
This invention relates to multi-compartment devices commonly utilized in separation technology and particularly in electrophoresis and in isoelectric focusing.
BACKGROUND OF THE INVENTION
There are many types of devices comprising two or more subcompartments that are separated from each other by septa like, for example, monofilament screens, membranes, gels, filters, and fritted discs. Generally, these devices are assembled from a plurality of essentially parallel frames or spacers, separated from each other by the septa. Some of these devices comprise a repetitive assembly of functional units requiring only two compartments, such as a repetitive assembly of input and output subcompartments in a filter press.
The invention is of particular relevance to electrophoretic devices where three or more subcompartments are aligned, and wherein transport of solutes potentially occurs across all the compartments. For instance, in U.S. Pat. No. 4,362,612 issued to Bier, the adjoining compartments are functionally designed to electrophoretically adjust to different pH values, thereby separating dissolved proteins according to their isoelectric points. Similar multiple subcompartments devices are described in U.S. Pat. No. 4,971,670 issued to Faupel et al., U.S. Pat. No. 5,173,164 issued to Egen et al., U.S. Pat. No. 4,963,236 issued to Rodkey et al., and U.S. Pat. No. 5,087,338 issued to Perry et al.
All of the above patents disclose devices comprising a series of parallel spacers that are separated from each other by septa, which results in an essentially parallel array of subcompartments. Apart from the cited patents, numerous other such devices have been disclosed in patents and other publications. In all such devices, electrodes are provided at the ends of the assembly of subcompartments for the application of an electrical field.
Each subcompartment of these devices usually includes an input port and an output port for circulation of process fluid. The septa have a primary function of streamlining the flow of liquid without unduly hindering the intercompartmental transport of solutes due to electrical or diffusional forces. The septa in these devices may also have other functions, depending on the intended use of the apparatus. In some instruments, like the above-identified Bier and Egen et al. devices, the septa are simply monofilament screens of fine porosity, and the relatively open nature of the septa are used to minimize interaction with the electric process. In the Faupel et al. device, on the other hand, the septa constitute buffered membranes of polyacrylamide gels impregnated on fiber-glass filters. The intended purpose of the buffered septa is to control the transport of proteins across the membranes, limiting this transport to only proteins of certain polarity. In yet other devices (Perry et al., for instance) membranes of controlled porosity are used to separate solutes according to particle size. In the present application, the generic term septum is utilized to describe all of the above possibilities, as these are all compatible with the invention at hand. In addition to such inter-compartment septa, most instruments require physical containment of electrolytes used around the electrodes, for which the term membrane will be used.
The production, assembly and use of such devices is complicated and made difficult by the multitude of component spacers and septa, all of which have to be assembled in a parallel sequence and sealed against fluid leaks.
SUMMARY OF THE INVENTION
The object of the present invention is to overcome this difficulty, and to provide a simpler design of devices incorporating three or more sequential subcompartments, separated from each other by septa. A device in accordance with the present invention is obtained by mating two planar surfaces, each surface provided with an array of adjacent cavities, and wherein the two surfaces are separated by the septum. Cavities on each of the surfaces are arranged to be out of sync with respect to cavities on the opposing surface, with the cavities being offset by a distance of roughly half a cavity width. In such a device, the sequential subcompartments formed by the cavities are no longer parallel to each other, but instead are arranged in a serpentine fashion, defining a hopscotched pathway moving to and fro across the septum. The multiple spacers and septa are accordingly reduced to as little as only the two mating surfaces and the septum, irrespective of the number of subcompartments. If an external electric field is applied, it will no longer be applied in a straight line from electrode to electrode, but will proceed essentially in a serpentine manner, winding across the septum to successive cavities in the two surfaces. Alternate designs accomplishing the same purpose are also disclosed herein.
While the design in accordance with the invention will result in lengthening the travel distance for migrating solutes, this is more than compensated by the simplicity of the design and use. For instance, this design makes it readily feasible to manufacture devices at sufficiently low cost to make them disposable. Disposable electrophoretic devices would greatly reduce the risk of product cross-contamination, simplify apparatus usage and contribute to the cleanliness and safety of overall operation.
In some applications, the septum is only a fluid flow streamliner, and has no other effect on the separation process. Thus, it may be possible to further simplify the device by eliminating the septum altogether. In such a case, the streamlining of the flow between successive subcompartments can be obtained by reducing the spacing between the mating surfaces of parts comprising the device, thus reducing the contact between successive sub-compartments to a narrow slit only. The resistance to fluid flow through a narrow slit is sufficient to essentially confine the flow through the wider cavities.
To apply such devices to electrophoresis and/or to isoelectric focusing, electrode compartments are included at both ends of the cavity array. It should be noted that the present design is applicable not only to electrophoresis, but also to other membrane devices where successive subcompartments may be desirable, such as, for example, in filters, electrodialyzers, and reverse osmosis devices.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and additional objects and advantages of the invention will become more apparent as the following detailed description is read in conjunction with the accompanying drawings wherein like reference characters denote like parts.
FIG. 1 is a schematic cross-section view of a device in accordance with one embodiment of the invention.
FIG. 2 is a schematic exploded view of the device shown in FIG. 1, illustrating further details of the invention.
FIG. 3 is a schematic cross-section view of a device in accordance with another embodiment of the invention.
FIG. 4 ms a schematic exploded view of a device in accordance with yet another embodiment of the invention.
FIG. 5 is a schematic illustration of an apparatus for isoelectric focusing incorporating a multi-channel device of the present invention.
FIG. 6 is a schematic illustration of the FIG. 5 apparatus illustrating the operation of collecting separated fractions.
FIG. 7 is a schematic illustration of an apparatus for isoelectric focusing illustrating an alternate method of collection of fractions.
DETAILED DESCRIPTION
In conventional multi-compartment electrophoretic devices, the electric field is oriented in a perpendicular direction to a parallel array of septa by means of electrodes contained in anodic and cathodic compartments of the devices. In addition, the devices include subcompartments, each of which is provided with an inlet and an outlet port, and fluid flow is provided through each subcompartment by external pumping means. The flow can be in single pass or recycled by means of fluid recycling loops. Other components may be included in the external flow channels, such as heat exchangers, reservoirs extending the volume capacity of each recirculating loop, and sensors for pH, temperature, and/or UV absorption, etc.
FIG. 1 illustrates a midline cross-section view of a multi-channel device 10 in accordance with one embodiment of the present invention. The device 10 includes two plate-shaped elements 12 and 14 that have mating planar surfaces. Each plate 12, 14 includes an array of roughly parallel cavities, which are labelled as 18, 22, 26, 30 and 34 on plate 12 and as 16, 20, 24, 28 and 32 on plate 14. While the cavities are shown to have a semicircular shape, the shape can be substantially varied as desired. It is important, however, that the distance separating adjacent cavities in each array, labelled 36 and 38, be significantly smaller than the width of each cavity. The cavity arrays of the two parts face each other, but are displaced with respect to each other, that is, each cavity on one plate is offset from a proximate cavity on the other plate, by a distance of about half a cavity width. A septum 40 is positioned between plates 12 and 14, separating the arrays of cavities.
In addition, block-shaped elements 42 and 44 are positioned in plates 12 and 14 to house electrolyte compartments 46 and 48, respectively. Electric current can be applied by means of electrodes 50 and 52, making contact with an external power supply (not shown) through connectors 54 and 56, respectively. The electrolyte compartments 46, 48 are separated from adjacent cavities 34, 16 by membranes 58 and 60, respectively. The membranes 58, 60 are permeable to current carrying ions, but impermeable to gross fluid flow.
In device 10, plates 12 and 14 are substantially identical. This, however, need not always be the case as it is equally feasible to place both electrode compartments on the same plate (either 12 or 14) by a suitable rearrangement of the cavities. Nor is there any limit to the number or dimensions of the cavities, which can be varied as required by the specific application of the device. There are preferably at least three cavities in the device since a device with two cavities may not achieve all of the advantages of the present invention.
FIG. 2 illustrates further details of the device shown in FIG. 1. Plates 12 and 14 are shown separated by septum 40. Each cavity 16-34 in plates 12 and 14 includes an essentially identical inlet port 62 and an essentially identical outlet port 64. The inlet and outlet ports are accessible by means of flexible tubing. Individual tubing can be attached to each inlet and outlet port, which however is a laborious task. Instead, FIG. 2 illustrates use of parts 66, 68 comprising "quick-connects" for multiple tubing. The parts 66, 68 include sets of inlet tubing 70 and outlet tubing 72, which lead to ports 74 and 76, respectively, which in turn are positioned to match corresponding inlet ports 62 and outlet ports 64, respectively, on the plates 12, 14.
Block-shaped elements 42, 44 are separated from the rest of the device by means of membranes 58, 60, respectively. Each electrolyte compartment 46, 48 also includes an inlet tubing connection 78 and an outlet tubing connection 80.
Repetitively placed holes 82 can be used for assembling the device by means of bolts (not shown). Obviously, there can be various other means of assembly, which means are not critical for the invention.
To assemble the device 10 of FIGS. 1 and 2, the two plates 12 and 14 are pressed together, sealing the septum 40. An electric field, when applied by means of the electrodes 50, 52, will not be oriented orthogonally to the septum 40 as in conventional multi-compartment cells such as described in the patents cited above, but will wind in a serpentine manner from cavity to cavity while taking the path of least resistance. Thus, the electric field will be approximately tangentially oriented relative to the septum 40 over most of its length. Any ionized material susceptible to electrophoretic transport will also migrate in a serpentine manner as long as its properties are compatible with its passage through the septum. If the process fluid is capable of generating a pH gradient, as in isoelectric focusing, the contents of each cavity will acquire a different pH. This can then be utilized for separation of proteins and other ampholytes, as is common in isoelectric focusing.
In the above design, the parts comprising the device may be machined from solid plastic such as plexiglass, molded out of a thermoplastic resin, or made by various other suitable manufacturing processes. The material should have chemical resistance to aqueous solutions, the electric field, and weak acids or bases. In addition, it is desirable to have optical clarity or at least some degree of transparency.
While the cavities in the plates 12, 14 need not have identical depths, they should preferably have matching widths and spacings. For instance, it may be preferable to have the cavities of one of the plates be deeper than in the other. In general, one may wish the depth of the cavity to be proportional to the width, with relatively minimal spacing in between the cavities, consonant with their manufacturing process.
FIG. 3 illustrates a device 100 in accordance with a further embodiment of the invention. The device 100 includes plate-shaped elements 102 and 104, wherein all of the cavities of the device, all labelled as 106, are located in plate 102. The mating surface of plate 104 is flat. This configuration obviates the need for a septum between the two plates. The primary role of the septum is to streamline the flow of liquid, providing an increased resistance to flow of liquid from cavity to cavity. In the device 100 of FIG. 3, flow streamlining is achieved by reducing the transport area between adjacent cavities to only a narrow slit between the bridges 108 of the cavities 106 and the flat plate 104. This distance may be controlled, for instance, by means of a spacer 110, which seals the inter-plate space. Obviously, other design modifications can also achieve a serpentine fluid pathway through an arrangement of cavities.
FIG. 4 illustrates a device 200 in accordance with a further embodiment of the invention also including a serpentine electric or fluid pathway. In this embodiment, the plates 12 and 14 of the FIG. 2 embodiment are replaced by element parts 202 and 204, each of which includes a plurality of throughholes 206 or cavities extending through the parts. This design provides a very simple assembly for the device, lending it suitable for use as a disposable item. The two parts 202, 204 could be made from an elastomer, which when pressed together would seal the screen and provide conduit to multi-channel quick-connects 208 and 210. The elastomer parts 202, 204 can be die-cut from elastomer sheeting or be injection molded from, for example, silicone rubber. The elastomer parts 202, 204 can be inserted between two end plates 208, 210 functioning as quick-connects and carrying attached tubing sets 70, 72. The end plates 208, 210 include appropriate channelling 212 to serve as fluid conduits between the throughholes 206 and the rest of the device.
This design also lends itself to easy cooling of process fluid in order to dissipate heat generated by electric current. Both electrode compartments 214, 216 can be mounted on one side of the device (part 208), leaving ample space for insertion of a cooling element 218 in the part 210. The cooling element 218 could be a metal plate cooled by a Peltier thermoelectric unit or by circulation of a refrigerant. Obviously, such a metal part could not come in direct contact with the process fluid, but could be located in a cut-out portion of part 210, which could act as an electrical insulator.
FIG. 5 illustrates an apparatus 300 used for isoelectric focusing including a multi-channel device 310 in accordance with the invention like, for example, the devices previously described. The multi-channel device 310 is connected by means of a tubing set 312 to a multi-channel pump 314 and a multiple pulse trap 316. An individual pulse trap, tubing loop and pump channel are assigned to each cavity and to the two electrode compartments in device 310. Optimally, each pulse-trap should have fluid capacity sufficient to prime the rest of the loop and the cavities in device 310. To prime the apparatus, all pulse-traps 316 are filled with process fluid and sealed by means of cover 318. Flow of fluid is started in the prime direction indicated at pump 314. The inlet to the loop is indicated at 320 and its return outlet to the pulse-trap is indicated at 322. Once fluid flow is established, the air evacuated from the recycling loops will form an air-pocket 324 at the top of each pulse-trap. At that time, the electric field can be applied from power supply 326 and the processing can be started. For isoelectric focusing, the process fluid should be capable of establishing or maintaining a pH gradient through appropriate buffering, as is well known in the art.
Alternatively, the septum in device 310 may contain a copolymerized pH gradient as taught by the Faupel et al. patent. Heat dissipation can be accomplished in various ways, either through direct cooling of the device 310 or through heat exchange with atmosphere or a cooling bath of tubing loops or the pulse-traps.
An important step in operation of the apparatus 300 is the collection of separated fractions. This should be carried out as smoothly as possible without interruption of fluid flow and major change in fluid pressures. As an essential step in the inventive process, part 316 is simply turned upside down, without interruption of fluid flow or, preferably, without interruption in electric power as shown in FIG. 6. This rotation reverses the priming process, replacing process fluid contents of each recycling loop with the air from the air-pockets 324, which now face the loop inlets 320. Such collection minimizes remixing of separated fractions contained in each recycling loops.
As an alternative, as shown in FIG. 7, collection of all fractions into the part 316 can be accomplished by reversing the direction of flow of process fluid by pump 314, emptying part 310. This requires that the air-pockets 324 in part 316 extend below return outlets 322.
EXAMPLE 1
A ten-loop device was utilized in this experiment. The two plates characterizing the device were identical, each including five semicircular cavities having a diameter of 0.250 inches and a length of 1 inch. The center-to-center spacing of the cavities was 0.270 inches, and thus, the bridge between the cavities was 0.020 inches. When assembled face-to-face, the cavities were offset by a length of half a cavity width with respect to each other. Each end-plate also contained an electrode compartment with a platinum wire electrode. The septum was a nylon monofilament screen having an effective pore size of 15 microns, and the electrode compartments were separated from the cavities by dialyzing membranes. A 12 channel peristaltic pump and 12-pulse-traps assembly completed the apparatus. The recycling flow rate was 1.5 ml/min/channel.
In the first experiment, a three component buffer was utilized, comprising 3 mM arginine, 10 mM d-cyclo-serine, and 4 mM p-aminobenzoic acid, pH 5.9. The electrolytes were 1.5 ml of 0.1M NaOH in the cathodic compartment and 1.5 ml of 0.1M phosphoric acid in the anodic one. The protein sample comprised 10 mg of human hemoglobin, naturally red, and 8 mg of bovine albumin, stained blue by the addition of minute quantities of bromo-phenol-blue dye. The inventors have often used such a system as a preliminary test of instrument function. While the separation is easy, the intense color permits observation of instrument performance.
The total priming volume was 14 ml, the priming having been carried out as described in FIG. 5. Focusing was started with 750 volts, resulting in a current of 15 mAmp. Within 30 minutes, at room temperature, a clear separation was observed, all the red color having been concentrated in the first channel 1 and all the blue color in the eighth channel. This was confirmed by collection of fractions achieved by a 180 degree turn of the pulse-trap assembly.
EXAMPLE 2
A more challenging separation was utilized in the second experiment, using the same apparatus. The protein sample was a commercial preparation of carbonic anhydrase. This enzyme comprises a plurality of closely spaced isoelectric fractions, differing from each other by only about 0.1 to 0.2 pH units. The same electrolyte buffers were used, but the fractionation was carried out in a solution of 30 mM MOPS, a so-called Good buffer, and 70 mM gamma-amino n-butyric acid. The run was started at 755 volts, 18 mAmp. Within 20 minutes the power was increased to 1000 volts, 14 mAmp, and at 60 minutes, the applied power was still 1000 volts, but the current decreased to 2 mAmp. The collection of the 10 fractions, carried out by reversing the orientation of the pulse traps, revealed the following pH values:
______________________________________ Fraction pH______________________________________ 1 6.88 2 6.87 3 6.64 4 6.10 5 5.97 6 5.82 7 5.73 8 5.45 9 4.88 10 2.76______________________________________
This pH profile corresponded to the expected values for the buffer used. A protein analysis carried out by conventional gel focusing technique revealed virtually no proteins in fractions 1 and 2, a single band in fraction 3, with increasing concentration of acidic proteins in fractions 4 to 7, and completely different acidic protein bands in fractions 8-10. | A multi-channel separation device is provided for use in separation technology, particularly in electrophoresis and in isoelectric focusing. The device includes two mating plates, at least one of which contains an array of at least three cavities arranged to define a serpentine fluid pathway through the cavities when the plates are mated. Each of the cavities includes fluid input and output ports to facilitate transfer of process fluid through the cavities. A septum is disposed between the plates for streamlining fluid flow between the input and output ports by restricting but not preventing free fluid flow between adjacent cavities. The device also includes anodic and cathodic compartments containing electrodes for establishing an electric field across the cavities. | 1 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method and a reagent for stabilizing biomaterials in a sample, and more particularly, to a method and a reagent for stabilizing nucleic acid in a biological sample.
[0003] 2. Description of Related Art
[0004] Nucleic acids are known to carry genetic information of an organism. Nowadays, nucleic acids also play important roles in the research fields of molecular biology. According to recent research results, it is known that genetic defects or diseases development of a patient can be deduced from the abnormality or special sequences of nucleic acids of that patient by clinical practice. Thus the goal for preventing disease occurrence can be achieved by detecting the abnormality of nucleic acids and taking necessary remedying steps for treatment before the onset of diseases. To achieve effective detection of abnormality or special sequences of the nucleic acids, the isolation of nucleic acids from an organism, as well as the steps for keeping the genetic information intact are the key subjects for related applications.
[0005] Nucleic acids are active molecules, especially RNA. Conventional methods for isolating active molecules of RNA are generally applied with anti-coagulants, for example—EDTA, into the phlebotomized whole blood, and then the sample is kept at 4° C. until the isolation steps can be performed. RNA expression levels would be affected by adding anti-coagulants, changing of temperatures, the periods of storage and the isolating process of leukocytes; these factors increase the difficulties for predicting disease occurrence by RNA expression. To get better results, isolating RNA from whole blood samples must be performed within 24 hours. However, this imperative processing time usually oppresses the medical technicians heavily, especially when large quantities of samples appear to operate.
[0006] PAXgene Blood RNA Tube and PAXgene Blood RNA Isolation Kit are developed and commercialized by Qiagen Company, and the two products co-operate for stabilizing and isolating nucleic acids in whole blood. However, the kits are not cost effective, hampering the applications of the kit to routine uses.
[0007] In WO2004013155, Goldsborough et al. discloses a method for stabilizing nucleic acids in a biological sample. The main steps for stabilizing nucleic acids in this method are to modify 2′, 3′, and 5′-OH groups of a nucleic acid with a protecting group first, which is to prevent the nucleic acids digestion by nuclease, and then the modified nucleic acids are treated with primary amines to remove the protecting group. The primary amine used here is only for deprotecting the protecting group rather than for forming a complex with nucleic acids.
[0008] On the other hand, in US 20040048384 to Augello, Frank A et al. discloses a collection container and method for collecting a predetermined volume of a biological sample, wherein the whole blood sample includes at least one gene induction-blocking agent in an amount effective to stabilize and inhibit gene induction. The stabilizing agent of the gene induction-blocking agent disclosed here is a quaternary amine. More discussion for the related method can be seen in the description of CA 2299119 in which a method for stabilizing and/or isolating nucleic acids is disclosed. The method described here uses at least two quaternary amines or cationic polymers with a phosphor group to precipitate and protect nucleic acids.
[0009] Moreover, a novel composition for isolating and/or stabilizing nucleic acids from biological materials is disclosed in US2004014703. The object of the method of US2004014703 is to provide a composition for stabilizing RNA in the presence of tissue, blood, plasma, or serum. The composition comprises a cationic compound like quaternary amine for nucleic acids stabilization.
[0010] There is no disclosure about stabilizing nucleic acids with primary amine, secondary amine or tertiary amine. Therefore, it is desirable to provide an improved method to mitigate and/or obviate the aforementioned problems.
SUMMARY OF THE INVENTION
[0011] The present invention provides a method to stabilize nucleic acids in a biological sample with amino surfactants. The mechanisms of nucleic acids stabilization and preservation of the present invention are different from conventional methods with anti-coagulants or a sample refrigerated at 4° C. Surfactants with primary amines, secondary amines and tertiary amines or the mixtures with various ratios of surfactants are used in the present invention, to stabilize nucleic acids by forming an insoluble ionic complex between nucleic acids and a surfactant. The complex protects RNA inside to prevent RNA degradation by RNase, as well as RNA transcription.
[0012] The present invention prolongs the periods of stabilization and preservation with simple procedures. The method also can be performed automatically to increase the throughput and expand the application of molecular diagnostic testing with nucleic acid.
[0013] To achieve the object, the stabilizing or preserving reagent and the method of the present invention for stabilizing or preserving nucleic acids by forming an insoluble ionic complex between nucleic acids and a surfactant in a biological sample comprises a step of contacting the sample with a stabilizing or preserving reagent consisted of amino surfactants of the formula (I):
R 1 R 2 R 3 N(O) x , (I)
[0014] wherein, R 1 and R 2 each independently is H, C1-C6 alkyl group, C6-C12 aryl group, or C6-C12 aralkyl group; R 3 is C1-C20 alkyl group, C6-C26 aryl group or C6-C26 aralkyl group; and x is an integer of 0 or 1.
[0015] When the stabilizing or preserving reagent of the present invention contacts with the biological sample, and an insoluble ionic complex is formed between nucleic acids and the surfactant in the stabilizing or preserving reagent. The complex protects RNA inside to prevent RNA degradation by RNase, as well as RNA transcription, hence the nucleic acids in the biological sample are stabilized and preserved.
[0016] One of the best embodiments is, R 1 and R 2 each independently is H or C1-C6 alkyl group; and R 3 is C1-C20 alkyl group when x is 0. The amino surfactants of the present invention can be any conventional amino surfactant. Preferably, the amino surfactant of the present invention is selected from the group consisting of dodecylamine, N-methyldodecylamine, N,N-dimethyldodecylamine, N, N-dimethyldodecylamine N oxide and 4-tetradecylaniline. The contact manner of the biological sample and the stabilizing or preserving reagent of the present invention are not limited, and can be a liquid solution or a solid-state composition. To obtain a better mixing result of the sample and the reagent, the preferred embodiment of the present invention reagent is in a manner of liquid solution.
[0017] The weight percentage of amino surfactants is not limited. Preferably, the weight percentage of amino surfactants in the solid-state composition is less than 90%, preferably, from 10% to 90%. When in solution form, the concentration of the amino surfactants in the reagent solution preferably ranges from 0.001% to 20%.
[0018] The method of the present invention can be performed without any presence of nonionic detergents or acids. However, the use of nonionic detergents, acids or the mixture thereof accompanied with specific amine surfactants might affect the results. Accordingly, the stabilizing or preserving reagent with amino surfactants can selectively further comprise at least one nonionic detergent. The nonionic detergent can be present as a liquid detergent or a solid one in the stabilizing or preserving reagent. The concentration of said nonionic detergent preferably ranges from 0.01% to 20% while the stabilizing or preserving reagent is in a liquid state; the weight percentage of the detergent ranges from 0.01% to 40% while the composition is in a solid state. The nonionic detergent of the present invention can be any conventional one; preferably, the nonionic detergent is polyoxyethylene. More preferably, the nonionic detergent is Tween 20 or Triton X-100, the most preferably, the nonionic detergent is Tween 20.
[0019] The stabilizing or preserving reagent with amino surfactants of the present invention can selectively further comprise at least one acid. The acid can be acid buffers or acid agents in a solid-state. The concentration of the acid buffer is less than 1 M. Preferably, the concentration of the acid buffer ranges from 0.01 to 0.5M. The acid can be any conventional one. More preferably, the acid is selected from a group consisting of maleic acid, tartaric acid, citric acid, oxalic acid carboxylic acids and mineral acids. The pH value of the stabilizing or preserving reagent of the present invention can be any value ranging from 1 to 14. Preferably, the pH ranges from 1 to 7, more preferably, the pH ranges from 1 to 5.
[0020] The biological sample with nucleic acids used may be cell-free sample material, plasma, body fluids such as blood, serum, cells, leucocyte fractions, sputum, urine, sperm, faeces, smears, aspirates, tissue samples of all kinds, such as biopsies, for example, parts of tissues and organs, food samples which contain free or bound nucleic acids or cells containing nucleic acids as envisaged according to the invention, such as organisms (single- or multi-cell organisms; insects, etc.), plants and parts of plants, bacteria, viruses, yeasts and other fungi, other eukaryotes and prokaryotes, etc.
[0021] The term “nucleic acids” for the purposes of the present invention denotes nucleic acids in the wider sense, and thus includes, for example, ribonucleic acids (RNA) and also deoxyribonucleic acids (DNA) in all lengths and configurations, such as double-stranded, single-stranded, circular and linear, branched, etc., and all possible subunits thereof, such as monomeric nucleotides oligomers, plasmids, viral and bacterial DNA and RNA, as well as genomic and non-genomic DNA and RNA from animal and plant cells or other eukaryotes, mRNA in processed and unprocessed form, tRNA, hn-RNA, rRNA, cDNA as well as all other conceivable nucleic acids. Preferably, the nucleic acids of the present invention are DNA or RNA.
[0022] Other objects, 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
[0023] FIG. 1 is an electrophoresis result of purified RNA in examples 1-3 of the present invention.
[0024] FIG. 2 is an electrophoresis result of purified RNA in examples 4-6 of the present invention.
[0025] FIG. 3 is a quantitative RT-PCR result of purified RNA in examples 7-9 of the present invention, which shows the relative gene expression levels in various preservation periods.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] The RNA expression level is determined by the quantity and the quality of the extracted RNA after several days by each of the 3 different methods to preserve whole blood samples.
Example 1
[0027] A 10 ml blood collection tube Vacutainer (EDTA K3, Becton Dickinson) is used to collect the whole blood samples. The sample in the Vacutainer is then stored at 4° C. for 0-4 days and the RNA is then isolated after periods of storage.
[0028] According to the supplier's handbook, 1 ml of Red Blood Cell Lysis Buffer (Roche Diagnostics GmbH) is added into 500 μl whole blood to purify leukocytes; then 150 μl of buffer RLT (QIAGEN GmbH) is added into leukocytes for cell lysis; 90 μl of ethanol is subsequently added into the sample. The sample is then applied into a centrifuge tube (QIAGEN GmbH) with silica membrane and a centrifugation step is taken.
[0029] The silica membrane in the centrifuge tube is washed with 350 μl buffer RW1 (QIAGEN GmbH), and the DNA molecules on the filter are removed with RNase-free DNase Set (QIAGEN GmbH). The silica membrane is then washed again with 350 μl buffer RW1, and twice with 500 μl buffer RPE (QIAGEN GmbH). The RNA molecules on the silica filter are then eluted twice with 40 μl RNase-free water eventually.
Example 2
[0030] In the present example, the collection of whole blood and RNA extraction is performed with PAXgene Blood RNA Validation Kit (QIAGEN GmbH). Blood sample is refrigerated at 4° C. for 0-4 days. After different storage periods, RNA is extracted directly according to the procedures described in the handbook as recommended by the vendor.
Example 3
[0031] In the present example, the whole blood sample for RNA extraction is stored with N-methyldodecylamine to stabilize RNA.
[0032] 33 μl of fresh whole blood is mixed with 1 ml of a stabilizing solution consisting of 3% (w/v) of N-methyldodecylamine, 5% (v/v) Triton X-100 and 100 mM tartaric acid and refrigerated for 0-4 days at 4° C. To isolate the RNA, the complexes of secondary amine surfactant and RNA are centrifuged at 5000×g for 10 min. The pellet is dissolved in 50 μl distilled water. 100 μl of buffer RLT (QIAGEN GmbH) and 10 μl of Proteinase K (QIAGEN GmbH) are added into the sample and incubated at 55° C. for 10 min. 200 μl of 1-bromo-3-chloropropane is added into the sample and mixed by vortexing. The sample is then centrifuged for 5 min at 10000×g.
[0033] The supernatant is then transferred into a new 1.5 ml tube. The sample is mixed with 90 μl of ethanol, and then applied to a spin column containing a silica membrane. The sample mixture is passed through the membrane under centrifugation. The silica membrane is washed with 350 μl of buffer RW1 (QIAGEN GmbH) and DNA molecules are eliminated by using the RNase-free DNase Set (QIAGEN GmbH). The silica membrane is washed with another aliquot of 350 μl of buffer RW1 and twice with 500 μl of buffer RPE (QIAGEN GmbH). Finally, the RNA molecules are eluted twice with the same aliquot of 40 μl of RNase-free water.
Example 4
[0034] In the present example, the whole blood sample for RNA extraction is stored with dodecylamine to stabilize RNA. A stabilizing solution consisting of 0.3% (w/v) of dodecylamine, 1% (v/v) Triton X-100 and 250 mM tartaric acid is prepared, and the pH value is adjusted to pH 3 with NaOH. A 1-ml fresh whole blood is mixed with 3 ml of the stabilizing solution, and then the sample is stored for 0-4 days at 4° C.
[0035] To isolate the RNA, the complexes of amine surfactant and RNA are collected by centrifugation. The pellet is dissolved in 150 μl distilled water. 300 μl of buffer RLT (QIAGEN GmbH) and 30 μl of Proteinase K (QIAGEN GmbH) are added into the sample and incubated at 55° C. for 10 min. 200 μl of 1-bromo-3-chloropropane is added into the sample and mixed by vortexing. The sample is then centrifuged for 5 min at 10000×g. The supernatant is then transferred into a new 1.5 ml tube. The sample is mixed with 270 μl of ethanol, and then applied to a spin column containing a silica membrane.
[0036] The procedures are subsequently followed in example 3.
Example 5
[0037] In the present example, the whole blood sample for RNA extraction is stored with N,N-dimethyldodecylamine to stabilize RNA. A stabilizing solution consisting of 5% (w/v) of N,N-dimethyldodecylamine, 2% (v/v) Triton X-100 and 140 mM tartaric acid is prepared. A 333-μl fresh whole blood is mixed with 1 ml of the stabilizing solution, and the mixture is frozen for 0-14 days at −20° C. The procedures of RNA isolating are performed following the description in example 3.
Example 6
[0038] In the present example, the whole blood sample for RNA extraction is stored with a stabilizing solution which consisting of 3% (w/v) of N,N-dimethyldodecylamine N oxide, 1% (v/v) Triton X-100 and 125 mM tartaric acid. The sample mixture is stored for 0-14 days at −20° C. RNA in samples of various storage periods is isolated following the procedures described in example 3.
Example 7
[0039] Agilent 2100 Bioanalyzer (Agilent Technologies) is used to analyze 28S/18S rRNA ratios of RNA isolated in examples 1-3. According to the standard ratio approved by those skilled in the art, the 28S/18S rRNA ratio higher than 1.5 means the RNA molecules are intact; on the other hand, the isolated RNA molecules are in good condition when the 28S/18S rRNA ratio is around 2.0. Besides, a good quality of RNA sample shows OD260/280 ratio in the range of 1.9-2.1 that is determined by a spectrophotometer. The methods described above are used to analyze the quality and quantity of RNA samples, and the results are listed in table 1 shown below.
TABLE 1 RNA yield RNA quality 28S/18S rRNA Samples (μg/ml) (OD 260/280) ratio Example 1 2.39 ± 0.69 2.00 ± 0.07 0.77 ± 0.08 Example 2 4.68 ± 0.68 1.94 ± 0.03 1.57 ± 0.13 Example 3 7.20 ± 0.48 1.98 ± 0.14 1.83 ± 0.17
[0040] Apparently, the results of example 3 in table 1 show a higher yield of RNA than example 1 or example 2. RNA yield of 7.20±0.48 μg can be isolated per ml blood with the stabilizing solution of the present invention in example 3. Also, a ratio of OD 260/280 is 1.98±0.14 as well as the 28S/18S rRNA ratio is 1.83±0.17, and both approach the highest quality value of 2.0.
[0041] FIG. 1 shows electrophoresis results of purified RNA in examples 1-3, wherein (a) is RNA resulted from example 1; (b) is resulted from example 2 and (c) is from example 3. The numbers 0-4 shown above the figure represent the days of storage. In the results of electrophoresis, the first band of each lane represents 28S rRNA and the second band represents 18S rRNA. Obviously, RNA isolated by the method of the present invention in example 3 has the best quality and quantity than the other two methods in example 1 or 2. The quantity and quality shows no differences between RNA samples from the 4-day storage and from the fresh blood (0-day storage).
[0042] FIG. 2 shows electrophoresis results of purified RNA in examples 4-6, wherein (a) is RNA resulted from example 4 with 0-2 days storage; (b) is resulted from example 5 with 0-14 days storage and (c) is from example 6 with 0-14 days storage. The data from Agilent 2100 Bioanalyzer (Agilent Technologies) are listed in table 2 below. According to the results of table 2 and FIG. 2 , RNA isolated from whole blood shows an acceptable condition even after 14 days storage.
TABLE 2 Samples Days of storage 28S/18S rRNA ratio Example 4 0 days 1.60 ± 0.14 1 day 1.60 ± 0.00 2 days 1.50 ± 0.00 Example 5 0 days 1.90 ± 0.26 7 days 1.80 ± 0.35 14 days 2.00 ± 0.36 Example 6 0 days 1.70 ± 0.44 7 days 1.53 ± 0.15 14 days 2.10 ± 0.26
Example 8
[0043] All procedures in the example are performed as per description in example 1, wherein the whole blood is stored for 0-2 days in 4° C.
Example 9
[0044] All procedures in the example are performed as per description in example 2, wherein the whole blood is stored for 0-2 days in 4° C.
Example 10
[0045] In the present example, 1 ml of whole blood sample for RNA extraction is stored with a 3-ml stabilizing solution consisting of 5% (w/v) of N,N-dimethyldodecylamine and 225 mM tartaric acid (the pH value is adjusted to pH 3.0 with NaOH). The sample mixture is stored for 0-2 days at 4° C. The procedures of RNA isolating are performed after various storage periods following the description in example 4.
Example 11
[0046] Single strand cDNA molecules are synthesized with the RNA molecules isolated form examples 8-10 by SuperScript II RNase H-Reverse Transcriptase (Invitrogen) according to the procedures described in the handbook as recommended by the vendor. The synthesized single strand cDNA molecules are subsequently performed with TaqMan Universal PCR master mix (Applied Biosystems) and Assays-on-Demand Gene Expression Products (Applied Biosystems), then a real-time PCR process is performed with ABI Prism 7000 Sequence Detection System (Applied Biosystems). The expression levels of 4 genes—ADORA2A, CREB5, NFKB1 and IFNGR1 are determined in different storage periods following the method described above, and the results are shown in FIG. 3 .
[0047] In FIG. 3 , the relative expression fold values represent the ratio of gene expression levels in RNA that are isolated from samples stored at 4° C. over 24-hour or 48-hour compared to no storage. For example, the relative expression fold value of 1 represents that the gene expression level of the isolated RNA molecules after certain period of time of storage is the same as that of 0-hour storage. A1-A4 in FIG. 3 are the results from example 8, wherein A1 is gene ADORA2A, A2 is gene CREB5, A3 is gene IFNGR1 and A4 is gene NFKB1. B1-B4 in FIG. 3 are the results from example 9, wherein B1 is gene ADORA2A, B2 is gene CREB5, B3 is gene IFNGR1 and B4 is gene NFKB1. C1-C4 in FIG. 3 are the results from example 10, wherein C1 is gene ADORA2A, C2 is gene CREB5, C3 is gene IFNGR1 and C4 is gene NFKB1. According to the data in FIG. 3 , the relative expression fold value is close to 1 in example 10 and the gene expression levels of the four genes show slight variations. Therefore, example 10 exhibits the best result of preserving nucleic acids in whole blood among these examples.
[0048] The embodiments demonstrate that nucleic acids in a biological sample can be stabilized or preserved with several stabilizing solutions containing primary amine, secondary amine or tertiary amine of the present invention. The present invention prolongs the periods of stabilization or preservation with simple procedures according to the data of the examples described above. The method also can be performed automatically to increase throughput and expand the application of molecular diagnostic testing with nucleic acids.
[0049] Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed. | A method for stabilizing or persevering nucleic acids by forming an insoluble ionic complex between nucleic acids and a surfactant in a biological sample, consisting of a step of contacting the biological sample with an isolation reagent comprising amino surfactants of the formula (I): R 1 R 2 R 3 N(O) x , (I), wherein, R 1 and R 2 each independently is H, C1-C6 alkyl group, C6-C12 aryl group, or C6-C12 aralkyl group; R 3 is C1-C20 alkyl group, C6-C26 aryl group or C6-C26 aralkyl group; and x is an integer of 0 or 1. Moreover, the concentration of the amino surfactants in the reagent ranges from 0.001% to 20%. The present invention also relates to a reagent for stabilizing or preserving nucleic acids in a biological sample. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates to apparatus for applying a liquid coating of food products by submergence in the liquid.
2. Description of the Prior Art
The present invention has broad application to the coating of a variety of food products with various liquid materials. However, it has particular utility in the coating of food products which are buoyant in the liquid used. For example, the ice cream sandwiched between a pair of cookies to form an ice cream sandwich is buoyant. When such a sandwich is submerged in a coating liquid such as chocolate syrup, the sandwich tends to float and frustrates efforts to coat the sandwiches by moving them through the liquid on a conveyor belt.
A typical prior art method for coating ice cream sandwiches with chocolate syrup involved manual placement of the sandwiches in an open mesh wire basket. The basket is pressed down into the chocolate syrup to overcome the buoyancy of the sandwiches. The coated sandwiches are then manually transferred onto trays. The excess chocolate syrup runs onto the trays and partially solidifies. This is wasteful of syrup and also makes it difficult to separate the sandwiches which are adhered to the trays. It is present practice to place the trays in a special freezer or hardening room to reduce the temperature of the trays enough for the chocolate coated sandwiches to be more easily broken free of the trays. The separated sandwiches can then be wrapped for storage or shipment.
The waste of materials, the high cost of the manual operations, and the capital investment required in expensive freezers undesirably raise the price of the final product sold to the public.
Another system of the prior art utilized conveyor belts which dipped down into the chocolate syrup only enough to coat the bottoms of the sandwiches. The top and sides were supposed to be coated by passage of the sandwiches through a falling curtain of chocolate syrup. However, this wasted syrup since it tended to pile on top of the upper cookie, and also the upper cookie acted somewhat like an umbrella and prevented the chocolate syrup from reaching the sides of the sandwiches. The sides could only be reached by side sprays, but this then limited the coating operation to a one-line assembly; that is, only one sandwich wide, and the production rate was very low.
SUMMARY OF THE INVENTION
According to the present invention apparatus is provided for applying a liquid coating to food products such as ice cream sandwiches by totally immersing or submerging them in the liquid material, and maintaining them in a submerged state in a manner and for a time sufficient for the liquid material to coat the complete exterior of the products.
The apparatus includes a relatively wide, continuous loop of dipper chain which travels in a generally longitudinal direction, dipping down into a container filled with the liquid coating material. The chain is characterized by a multiplicity of interstices so that the liquid can easily flow in and about the food products. The apparatus further includes restraining means located above the dipper chain and operative upon the tops of the submerged food products to prevent buoyant products from floating out of the liquid material. In one embodiment the restraining means comprises an apertured pressure plate. The food products slide across the underside of the plate, and liquid material flows through the plate apertures onto the tops of the food products. In another embodiment the restraining means takes the form of a continuous chain heavy enough to press down upon the food products as it moves with the products through the liquid coating material.
The apparatus preferably also includes a drive mechanism adapted to move the dipper chain intermittently so that the food products are momentarily stopped as they come out of the liquid. Excess liquid can then drip from the products back into the liquid container.
A continuous drying chain is preferably longitudinally aligned with the dipper chain. It is characterized by a multiplicity of interstices to minimize the area of contact with the food products and is operative to accept the products for travel along a drying run. The drying chain is flexible and supported at intervals sufficiently great that the chain sags into a succession of peaks and valleys. This causes the bottoms of the food products to tip or rock forward and backward as they move along the drying run, and thereby prevents undesirable sticking of the hardening coating material to the drying chain.
A transfer mechanism is provided between the dipping chain and the drying chain to facilitate transfer of the food products from one to the other, the transfer mechanism preferably being operative to engage and move the food products at a rate of travel greater than the rate of travel imparted to them by the dipper chain.
As a consequence of the foregoing, the coating operation is substantially completely automated, thereby reducing labor costs to a minimum and eliminating any need for rehardening or refreezing of the food products prior to wrapping for storage or shipment.
Other objects and features of the invention will become apparent from consideration of the following description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially diagrammatic top plan view of the present apparatus for applying a liquid coating to food products, including a showing of the associated freezer and heater units;
FIG. 2 is a partial top plan view of the left or feed extremity of the coating apparatus;
FIG. 3 is a right side elevational view of the portion of the apparatus illustrated in FIG. 2;
FIG. 4 is a view taken along the line 4--4 of FIG. 2, together with a partial showing of the right or discharge extremity of the apparatus;
FIG. 5 is a view taken along the line 5--5 of FIG. 2;
FIG. 6 is an enlarged detail view of the height adjustment assembly for the pressure plate;
FIG. 7 is an enlarged partial detail view of a portion of the dipper chain engaged upon one of the drive sprockets; and
FIG. 8 is a view similar to FIG. 5, but illustrating another form of restraining means for maintaining the food products submerged during the coating operation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and particularly to FIG. 1, an apparatus 10 is illustrated for applying a liquid coating to food products such as application of chocolate ice cream sandwiches. It will be understood, however, that the coating of ice cream sandwiches is merely exemplary and that various other food products can be coated with the present apparatus.
A conventional freezing tunnel or freezer 12 located adjacent the apparatus 10 accepts uncoated ice cream sandwiches placed upon a conveyor 14. The conveyor 14 carries the sandwiches through the freezer 12 in a generally longitudinal direction and deposits them on a transversely moving conveyor 16. The freezer 12 lowers the temperature of the sandwiches enough to enable the sandwiches to be coated without melting. It forms no part of the present invention.
The conveyor 16 moves the sandwiches to an operator station adjacent the feed end of the apparatus 10. An operator takes the sandwiches off the conveyor 16 and places them upon a continuous dipper chain 18 to initiate the coating operation. If desired, the operation can be more completely automated to eliminate manual transfer of the sandwiches from the conveyor 16, as will be apparent to those skilled in the art.
As best seen in FIGS. 2 through 4, the dipper chain 18 is carried by a longitudinally extending frame having a pair of ends 20, a pair of sides 22, three transversely disposed cross members 24 secured to the sides 22, and supporting legs 26.
A plurality of transversely aligned, longitudinally spaced apart pairs of upright shaft supports 28 and 29 are secured at their lower extremities to the opposite sides 22 of the frame. Each pair of supports 28 rotatably supports the ends of a transverse sprocket shaft 30, and each shaft 30 mounts a plurality of uniformly transversely spaced apart toothed conveyor elements or sprockets 32. Each pair of supports 29 rotatably supports the ends of a transverse roller shaft 33, and the shaft 33 mounts a plurality of uniformly transversely spaced apart collars or rollers 112.
An upwardly open, transversely extending rectangular container 34 is secured to the feed end 20 of the apparatus frame, and rests upon and is also secured to the transverse cross braces 24. The container 34 is adapted to hold coating material such as chocolate syrup 38, as best seen in FIG. 5. The syrup 38 is preferably maintained at a uniform temperature of approximately 110 degrees Fahrenheit to facilitate coating of the ice cream sandwiches, generally indicated at 40 in FIG. 2. At room temperature the frozen sandwiches cause the syrup to solidify into a semi-hard chocolate layer.
The heater is diagrammatically indicated at 42 in FIG. 1. It forms no part of the present invention and may be any commercially available heater suitable to accept a supply of syrup, heat it and pump it into the container 34 for use. In the illustrated arrangement a supply of syrup is poured into the heater reservoir (not shown), from which it is pumped through an inlet conduit 44 to the container 34. When the liquid reaches the desired level, as seen in FIG. 5, the excess overflows through an outlet conduit 46 and passes back to the heater for reheating and continuous circulation.
The dipper chain 18 is a continuous, longitudinally disposed loop, and extends across substantially the entire width of the container 34. It travels in a generally longitudinal direction and is characterized by a multiplicity of interstices 48 which are defined by a grid of intersecting wires 50 and 52. The wires 50 extend across the width of the chain, while the wires 52 are a plurality of short sections which are looped at opposite ends about adjacent wires 50. With this arrangement the wires 50 and 52 are movable relative to one another to render the chain 18 sufficiently flexible to pass around the various sprockets 32, as best seen in FIGS. 2 and 7.
The wires 50 are successively received between the cogs or teeth of the sprockets 32. Clockwise rotation of the sprockets 32 is operative to advance the chain 18 in a generally clockwise direction, as seen in FIG. 5, to advance the sandwiches 40 through the submerged run 56 and toward the discharge end of the apparatus 10. Certain ones of the wires 50 are bent upwardly generally normal to the plane of the adjacent wires 50 and 52 to form four, transversely spaced apart portions or carrier dogs 54, as seen in FIG. 2, to engage and move four sandwiches 40. Of course, the number of dogs 54 can vary, depending upon the width of the apparatus desired.
Each wire 50 provided with the dogs 54 is longitudinally spaced from the next wire 50 provided with the dogs 54 a distance slightly greater than the diameter of one of the sandwiches 40 to provide adequate space for the sandwiches to occupy.
Chain suitable for the dipper chain 18 is available commercially as stainless steel wire belt. It is commonly used to convey food products in food processing operations.
As best seen in FIG. 5, dipper chain 18 slopes or dips down into the container 34 to define a submerged run 56. Thereafter, it rises out of the container at approximately a 45° angle to define a drip run 58.
Ice cream is naturally buoyant in the chocolate syrup 38 and a restraining means in the form of an arcuate, transversely extending squeegee and pressure plate 60 is provided to prevent floating of the sandwiches 40 during their passage through the submerged run 56. The curved underside of the plate 60 is spaced just above the submerged run 56 of the chain 18, the spacing approximating the thickness of a sandwich 40 so that the plate slidably engages the tops of the sandwiches 40 and holds them down as they travel toward the drip run 58.
The upper left or feed edge of the plate 60, as seen in FIGS. 2 and 5, includes one or more curved or reversely form sections which rotatably fit about a transverse shaft 62 supported at its opposite ends by a pair of upright plates 64. Plates 64 are attached at their lower ends to the opposite frame sides 22 by usual wing nuts threaded onto bolts (not shown) carried by the frame sides and passing through vertical slots in the plates 64. As will be apparent, loosening of the wing nuts allows the height of the plates 64 and shaft 62 to be adjusted.
The opposite or discharge edge of the plate 60 includes a centrally located, right angular section having a horizontal tab 66 which rests upon the upper end of a vertically disposed, threaded bolt 68, as best seen in FIGS. 5 and 6. The bolt 68 is threaded through a transverse element 70 which is secured at its opposite ends to the pair of downstream shaft supports 28. Rotation of the bolt 68 in opposite directions raises and lowers the tab 66. This, together with adjustment of the height of the shaft 62, enables adjustment of the vertical position of the pressure plate 60 for accommodating food products of different thicknesses. A lock nut 74 threaded onto the bolt 68 is tightened against the element 70 to maintain its adjusted position. The weight of the plate 60 is sufficient to cause it to bear down against the tops of the sandwiches 50 and keep them submerged in the syrup 38. However, the plate 60 is free to rise at its discharge end and prevent jamming if, for example, an oversize sandwich entered the submerged run 56.
A pair of guides or plate segments 75 are located at opposite sides of the plate 60. The segments include arcuate lower edges and are made of low friction bearing material such as an acetyl resin of the type which is a crystalline form of polymerized formaldehyde, one form being known in the trade by the trademark DELRIN, owned by E. I. Du Pont de Nemours & Co. The segments 75 are secured to the horizontal legs of a pair of angle brackets 73 whose upright legs are vertically slidably engaged upon the frame sides 22, respectively. The upright legs of the brackets 73 are adjustably held in a selected vertical position by a pair of wing nuts 72 threaded onto bolts (not shown) extending into the frame sides 22 through vertical slots in the brackets 73. The slots extend to the bottom of the brackets 73 to enable removal and cleaning of the segments 75 and brackets 73.
The arcuate undersides of the segments 75 bear against the dipper chain 18 and cause it to assume a shape complemental to that of the pressure plate 60 for properly supporting the sandwiches 40 in the submerged run 56.
The arcuate central portion of the plate 60 is provided with a plurality of staggered apertures 76 to allow syrup 38 to flow down onto the top of the sandwiches 40. Without the apertures 76, the underside of the plate 60 has a wiping or squeegee effect which tends to control the quantity of syrup 38 which builds upon the sandwich tops, depending upon the upwardly or downwardly adjusted position of the plate 60 and the size of the sandwich.
An alternative embodiment is illustrated in FIG. 8 for maintaining the sandwiches 40 in submerged relation during their passage through the submerged run 56. Instead of using a pressure plate 60, the restraining means takes the form of a continuous loop of upper chain 78 substantially identical in construction to the chain 18, but without the carrier dogs 54. The upper chain 78 is made of material sufficiently heavy that the weight of the lower run of the chain 78 is sufficient to overcome the natural buoyancy of the sandwiches 40.
The chain 78 is disposed about a pair of transverse sprocket shafts 31 rotatably supported at their opposite ends by two pairs of transversely aligned longitudinally spaced apart upright supports 80 secured to the opposite frame sides 22. Each of the shafts 31 is characterized by a plurality of the sprockets 32 for engagement and movement of the chain 78 upon rotation of the shafts 31. The upper chain 78 moves at generally the same rate as the dipper chain 18 and the multiplicity of apertures in the chain 78 allows syrup 38 to coat the sandwich tops. The chain 78 is positively driven by a conventional take-off from the drive system for the chain 18 (not shown), as will be apparent.
As best seen in FIG. 4, a drive means 82 is provided for driving the chain 18. Although the drive means can be one which drives the chain at a constant rate, it preferably takes the form of a conventional stepper mechanism 84. An output shaft 86 of the mechanism mounts a sprocket 88 for rotation in a clockwise direction. This operates a drive chain 92 which rotates a sprocket 90 mounted to the sprocket shaft 30 located nearest the discharge end of the machine.
The stepper mechanism 84, as is well known, is operative to provide an intermittent movement of the dipper chain 18. This allows excess liquid coating on the sandwiches 40 to drain off while the sandwiches are halted in the drip run 58.
The stepper 84 is not a part of the present invention, being well known to those skilled in the art, and it will therefore be only generally described. It is a racheting mechanism which includes in internal piston (not shown) movable to the left, as viewed in FIG. 4, by application of pneumatic pressure through a conduit 94. Air on the opposite side of the piston is exhausted through a conduit 96. As the piston moves to the left, a rack associated with the piston rotates a pinion (not shown) connected to by a one-way clutch bearing to the shaft 86. This rotates the shaft 86 in a clockwise direction.
The piston is returned by pneumatic pressure applied to conduit 96, with the clutch slipping or overriding so that the shaft 86 is not rotated. During return movement of the piston the dipper chain 18 is a stationary and is only again moved in a clockwise path when the stepper mechanism 84 is again actuated by pneumatic pressure applied at the inlet conduit 94. The pneumatic system is also conventional and is therefore not described in detail.
The continuous drying chain 98 is substantially identical to the dipper chain 18, differing essentially in that it does not include the carrier dogs 54. Chain 98 is longitudinally aligned with chain 18 for receipt of coated sandwiches 40. Chain 98 includes an upper or drying run 100 which passes over the roller shaft 33 at the feed end of the chain 98, over a sprocket shaft 30 at the discharge end of the chain 98, and also over a plurality of longitudinally spaced apart intermediate roller shafts (not shown) located between the roller shaft 33 and sprocket shaft 30. The drying run 100 is considerably longer than is illustrated, the showing being shortened in the drawings to save space.
The chain 98 is engaged by sprockets 32 of the shaft 30 in the same manner as the chain 18 is engaged by the sprockets 32 of the chain 18.
The longitudinal intervals between the shaft 33, intermediate roller shafts (not shown), and shaft 30 are sufficiently great that the chain 98 sags or dips between the shafts to form a succession of catenaries or peaks and valleys. The peaks are defined by the sections of chain 98 riding over the shafts, and the valleys are defined by the lower lying sections of chain located intermediate the shafts. With this arrangement the bottoms of the sandwiches 40 do not travel in a purely horizontal plane, but instead alternately ride up upon the shafts tipping backwardly, and then ride downover the shafts, tipping forwardly. This alternate rocking back and forth breaks the sandwich bottoms away from the chain 98 and prevents adherence to the chain of the hardening chocolate coating.
The stepper mechanism 82 not only intermittently drives the chain 18, but also the drying chain 98. As best seen in FIG. 4, a drive sprocket 102 mounted to the output shaft 86 drives a chain 104. This rotates a sprocket 106 carried by the sprocket shaft 30. The diameters of the sprockets are preferably selected such that the rate of movement of the drying chain 98 is one-third that of the dipper chain 18. However, the relative rates of travel are somewhat empirical and can be adjusted as required.
A transfer mechanism is provided for conveying the sandwiches 40 from the dipper chain 18 to the drying chain 98. As best seen in FIGS. 2 and 4, the mechanism comprises a transverse roller shaft 108 rotatably mounted at its opposite extremities to a pair of upright plates 110 which are secured at their lower extremities to the frame sides 22.
The discharge end of the dipper chain 18 and the feed end of the drying chain 98 are longitudinally spaced apart a short distance, and the roller shaft 108 is located in this space. The shaft 108 mounts a plurality of transversely spaced rollers 112. As will be seen, these rollers 112 are rotated clockwise by the shaft 108 at a rate such that they move the sandwiches 40 approximately twice as fast as the sandwiches are moved by the dipper chain 18. This tends to pull the sandwiches off the chain 18 before they have a chance to dip down prior to riding onto the chain 98. That is, the freshly coated sandwiches 40 ride off the discharge end of the dipper chain 18 just as the chain 18 passes about the end discharge sprocket, and the more rapidly rollers 112 engage and thrust the sandwiches 40 onto the adjacent feed end of the drying chain 98, pulling the sandwiches 40 away from the carrier dogs 54 of the dipper chain 18 before there is any opportunity for the sandwiches to flip over under the impetus of the moving chain 18.
The stepper 84 drives the roller shaft 108 through a sprocket 114 mounted to the shaft 108. More particularly, a sprocket 116 is carried by a jack shaft 118 which is rotatably mounted to the adjacent frame side 22 just below the sprocket 114. The sprockets 114 and 116 are coupled together by a drive chain 120. Another sprocket (not shown) is also mounted to the jack shaft 118 adjacent and inwardly of the sprocket 116. It is engaged by the drive chain 92 to effect rotation of the sprocket 114 by the drive chain 92.
The diameter of the sprockets 114 and 116 is selected such that the desired rate of movement of the sandwiches 40 by the rollers 112 is approximately twice that imparted by the dipping chain 18.
In operation, uncoated sandwiches 40 are manually placed upon the conveyor 14 for passage through the freezer 12. When the sandwiches leave the freezer 12 the ice cream is sufficiently hardened that the sandwiches can be coated with the chocolate syrup 38 without melting of the ice cream. Sandwiches leaving the freezer 16 are deposited upon the transverse conveyor 16, and an operator manually transfers four of the sandwiches from the conveyor 16 to positions ahead of four of the carrier dogs 54 on the dipper chain 18.
The chain 18 carries the sandwiches through the submerged run 56, the pressure plate 60 holding the sandwiches in a submerged state while the coating takes place. Apertures 76 in the plate 60 facilitate coating the tops of the sandwiches, as previously described.
The coated sandwiches are momentarily halted in the drip run 58 by virtue of the intermittent drive which characterizes the stepper 84, allowing excess syrup to drain back into the container 34.
Sandwiches leaving the dipper chain 18 are engaged by the more rapidly rotating rollers 112 of the transfer mechanism, and are thrust onto the feed end of the drying chain 98.
The drying chain 98 is supported such that it drapes itself into a series of peaks and valleys between its support points. This causes the sandwiches 40 to rock as they negotiate the peaks and valleys, thereby breaking them free of adherence with the drying chain 98. Such breaking loose is also facilitated by the trembling and shaking of the flexible chain as it moves through the drying run 100 to advance the sandwiches 40 toward the wrapping station (not shown) at the discharge end of the chain 98.
Various modifications and changes may be made with regard to the foregoing detailed description without departing from the spirit of the invention. | Apparatus for applying a liquid coating to food products, including a continuous dipper chain which submerges the food products in the coating liquid. A restraining mechanism in the form of a pressure plate or chain acts upon the tops of the products to maintain them in submerged position during travel through the liquid. In one embodiment the dipper chain is driven intermittently to allow excess liquid on the food products to drain off. A continuous drying chain is provided to carry coated food products along a drying run, a transfer system being employed for moving the food products from the dipper chain to the drying chain. The drying chain is flexible and supported at relatively great intervals to allow the chain to form into peaks and valleys. The food products tip forward and backward in negotiating these peaks and valleys, breaking away the bottoms of the food products and the drying chain and preventing adherence. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 USC §119(e) of U.S. Provisional Application Nos. 61/269,975, filed Jul. 1, 2009, and 61/205,235, filed Jan. 20, 2009, the entireties of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The field of the invention is directed to methods for reprogramming somatic cells to a less differentiated status. In particular, the field of the invention is directed to methods for reprogramming amnion epithelial cells (AEC), including amnion-derived cells (ADC) and Amnion-derived Multipotent Progenitor cells (AMP cells), to a less differentiated status. The field is further directed to compositions comprising reprogrammed AEC, ADC and AMP cells, and uses thereof.
DESCRIPTION OF RELATED ART
[0003] Yamanaka, S. (Philos Trans R Soc Lond B Biol Sci 2008 363 (1500):2079-87) reviews molecular mechanisms of and known methods of inducing pluripotency in somatic cells.
[0004] Yamanaka, S. (Cell Prolif 2008 Suppl 1:51-6) describes induction of pluripotent stem cells from mouse fibroblasts by four transcription factors.
[0005] Okita, K., et al., (Science 2008 322 (5903) 949-53, Epub 2008 Oct. 9) describe generation of mouse induced pluripotent stem cells with out viral vectors.
[0006] Park, I. H., et al., (Nature 451:141-6, 2008) describe reprogramming of human somatic cells to pluripotency with defined factors.
[0007] Yu, J., et al., (Science 318:1917-20, 2007) describe induced pluripotent stem cell lines derived from human somatic cells.
[0008] Takahashi, K., et al., (Nat Protoc 2007 2 (12):3081-9) describe induction of pluripotent stem cells from fibroblast cultures.
[0009] Oliveri, R. S. (Regen Med 2007 2 (5):795-816) reviews epigenetic dedifferentiation of somatic cells into pluripotency.
[0010] Alberio, R., et al., (Reproduction 2006 132 (5):709-20) reviews reprogramming somatic cells into stem cells.
[0011] U.S. Publication No. 20080280362, published Nov. 13, 2008, describes methods for reprogramming somatic cells.
BACKGROUND OF THE INVENTION
[0012] The differentiation status of cells is a continuous spectrum, with the terminally differentiated state at one end and de-differentiated state (the pluripotent state) at the other end. Reprogramming encompasses any movement of the differentiation status of a cell along the spectrum toward a less-differentiated state. For example, reprogramming includes reversing a multipotent cell back to a pluripotent cell or reversing a terminally differentiated cell back to either a multipotent cell or a pluripotent cell.
[0013] Much research is directed to developing methods for reprogramming cells to a less differentiated status. Such methods include but are not limited to viral-induced reprogramming through the introduction of pluripotency genes into cells via viral vectors, contacting cells with chemical agents (i.e. demethylating agents) that alter chromatin structure and consequently differentiation status, nuclear transfer methodologies, and contacting cells with unique media and matrix combinations that effect dedifferentiation. Most of the methods described thus far have been successful to at least some degree in most cells tested, although some, for example viral-induced dedifferentiation and reprogramming, do have associated risks such as teratoma formation which make the clinical application of these reprogrammed cells not feasible at this time.
SUMMARY OF THE INVENTION
[0014] The invention is directed to methods for reprogramming somatic cells to a less differentiated status. In particular, the field of the invention is directed to methods for reprogramming amnion epithelial cells (AEC), including amnion-derived cells (ADC) and Amnion-derived Multipotent Progenitor cells (AMP cells), to a less differentiated status. In accordance with the methods of the invention, the AEC, ADC and/or AMP cells, are contacted with a candidate agent capable of effecting reprogramming of the cells to a less differentiated status. Dedifferentiated cells are then selected and assessed for pluripotency characteristics (i.e., teratoma formation, embryoid body formation, expression of pluripotent cell markers, lack of expression of differentiation markers, etc.). The presence of at least a subset of pluripotency characteristics in the cells indicates that the agent is capable of reprogramming the cells to a less differentiated status. The invention is further directed to compositions comprising the reprogrammed cells, as well as uses of the reprogrammed cells. Once reprogrammed, the cells are termed AEC R , ADC R and AMP R cells. AEC R , ADC R and AMP R cells can be treated with various differentiation media, agents, condition, etc., to induce them to differentiate down any cellular pathway. For example, the AEC R , ADC R and/or AMP R can be exposed to conditions known to effect neural differentiation, pancreatic differentiation, hematopoietic differentiation, and the like. The advantage of using AEC, ADC and/or AMP cells is that the cells are obtained from a non-controversial source, the normally discarded placenta, and therefore do not possess the assorted ethical, religious or political issues that are associated with ES cells. In addition, AEC, ADC and/or AMP cells may already express one or more pluripotency genes (i.e. Oct4), which may aid in the dedifferentiation of these cells.
[0015] Accordingly, a first aspect of the invention is a method of reprogramming amnion epithelial cells to a less differentiated state comprising contacting the cells with an agent capable of effecting such reprogramming. In one embodiment the amnion epithelial cells are amnion-derived cells or AMP cells. In another embodiment the amnion epithelial cells are human amnion epithelial cells. In still another embodiment the agent is a pluripotency gene. And in a specific embodiment the pluripotency gene is Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella. Other specific embodiments are ones in which the pluripotency gene is one of Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella; the pluripotency gene is two of Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella; the pluripotency gene is three of Oct4, Sox2, Klf4, nanog, Lin28, Stella or c-Myc; the pluripotency gene is four of Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella; the pluripotency gene is five of Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella; the pluripotency gene is six of Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella; or the pluripotency gene is all of Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella.
[0016] In another embodiment, the pluripotency gene is delivered to the amnion epithelial cell by retrovirus-mediated transfection, lentivirus-mediated transfection, adenovirus-mediated DNA transfection or non-viral-mediated DNA transfection. In still another embodiment the agent is a demethylating agent or a deacetylation agent. In a specific embodiment the demethylating agent is a 5-aza-cytidine or 5-azadeoxycytidine. In another specific embodiment the deacetylation agent is trichostatin A, trapoxin B, depsipeptides, benzamides, electrophilic ketones, phenylbutyrate or valproic acid. In another embodiment the less differentiated state is totipotency or pluripotency.
[0017] A second aspect of the invention is a dedifferentiated cell made by the method of the first aspect.
[0018] A third aspect of the invention is a method of treating a disease or disorder in a subject in need thereof comprising transplanting the dedifferentiated cell of the second aspect into the subject.
[0019] A fourth aspect of the invention is a composition comprising AEC R , ADC R or AMP R cells, or a combination thereof, wherein the cells exhibit pluripotency characteristics. In one embodiment the pluripotency characteristic is expression of one or more ES cell markers. In a specific embodiment the ES cell markers are Oct4, SSEA1, SSEA3, SSEA4, elevated Alkaline Phosphatase levels, nestin, AC133, Tcf4 or Cdx1. In still another embodiment the pluripotency characteristic is expression of pluripotency genes. And in a particular embodiment the pluripotency genes are one or more of Oct4, Sox2, Klf4, m-Myc, nanog, Lin28, or Stella. In yet another embodiment the pluripotency characteristic is the ability to differentiate into any cell type in body. And in another embodiment the pluripotency characteristic is the ability to form embryoid bodies. In still another embodiment the pluripotency characteristic is having the capacity for self-renewal.
[0020] A fifth aspect of the invention is a composition comprising AEC R , ADC R or AMP R cells wherein the cells are capable of forming any cell type which arises from the endoderm. In particular embodiments, the cell type which arises from the endoderm is a stomach cell, colon cell, liver cell, pancreas cell, urinary bladder cell, lining of the urethra cell, epithelial parts of the trachea cell, lung cell, pharynx cell, thyroid cell, parathyroid cell, or intestinal cell.
[0021] A sixth aspect of the invention is a composition comprising AEC R , ADC R or AMP R cells wherein the cells are capable of forming any cell type which arises from the mesoderm. In particular embodiments, the cell type which arises from the mesoderm is a skeletal muscle cell, skeletal cell, dermal cell, connective tissue cell, urogenital system cell, heart cell, blood cell, lymph cells, or spleen cell.
[0022] A seventh aspect of the invention is a composition comprising AEC R , ADC R or AMP R cells wherein the cells are capable of forming any cell type which arises from the ectoderm. In particular embodiments, the cell type which arises from the ectoderm is a central nervous system cell, lens cell, cranial and sensory nerve cell, motor nerve cell, ganglion cell, pigment cell, head connective tissue cell, epidermal cell, hair cell, or mammary gland cell.
Definitions
[0023] As defined herein “isolated” refers to material removed from its original environment and is thus altered “by the hand of man” from its natural state.
[0024] As defined herein, a “gene” is the segment of DNA involved in producing a polypeptide chain; it includes regions preceding and following the coding region, as well as intervening sequences (introns) between individual coding segments (exons).
[0025] As used herein, the term “marker” means any molecule characteristic of a cell or in some cases of a specific cell type.
[0026] As used herein, the term “protein marker” means any protein molecule characteristic of a cell or in some cases of a specific cell type. Protein markers may be located on the cell membrane, may be intracellular or may be secreted from the cell.
[0027] As used herein, “enriched” means to selectively concentrate or to increase the amount of one or more materials by elimination of the unwanted materials or selection and separation of desirable materials from a mixture (i.e. separate cells with specific cell markers from a heterogeneous cell population in which not all cells in the population express the marker).
[0028] As used herein, the term “substantially purified” means a population of cells substantially homogeneous for a particular marker or combination of markers. By substantially homogeneous is meant at least 90%, and preferably 95% homogeneous for a particular marker or combination of markers.
[0029] The term “placenta” as used herein means both preterm and term placenta.
[0030] As used herein, the term “totipotent stem cells” shall have the following meaning. In mammals, totipotent cells have the potential to become any cell type in the adult body; any cell type(s) of the extraembryonic membranes (e.g., placenta). Totipotent cells are the fertilized egg and approximately the first 4 cells produced by its cleavage.
[0031] As used herein, the term “pluripotent stem cells” shall have the following meaning. Pluripotent stem cells are true stem cells with the potential to make any differentiated cell in the body, but cannot contribute to making the components of the extraembryonic membranes which are derived from the trophoblast. The amnion develops from the epiblast, not the trophoblast. Three types of pluripotent stem cells have been confirmed to date: Embryonic Stem (ES) Cells (may also be totipotent in primates), Embryonic Germ (EG) Cells, and Embryonic Carcinoma (EC) Cells. These EC cells can be isolated from teratocarcinomas, a tumor that occasionally occurs in the gonad of a fetus. Unlike the other two, they are usually aneuploid.
[0032] As used herein, the term “multipotent stem cells” are true stem cells but can only differentiate into a limited number of types. For example, the bone marrow contains multipotent stem cells that give rise to all the cells of the blood but may not be able to differentiate into other cells types.
[0033] The term “self-renewal” as used herein means a cell or population of cells having the ability to go through numerous cycles of cell division while maintaining the undifferentiated state.
[0034] The term “somatic cells”, as used herein, also includes adult stem cells. An adult stem cell is a cell that is capable of giving rise to all cell types of a particular tissue. Exemplary adult stem cells include hematopoietic stem cells, neural stem cells, and mesenchymal stem cells.
[0035] The term “pluripotency gene”, as used herein, refers to a gene that is associated with pluripotency. The expression of a pluripotency gene is typically restricted to pluripotent stem cells, and is crucial for the functional identity of pluripotent stem cells.
[0036] As used herein, the term “extraembryonic tissue” means tissue located outside the embryonic body which is involved with the embryo's protection, nutrition, waste removal, etc. Extraembryonic tissue is discarded at birth. Extraembryonic tissue includes but is not limited to the amnion, chorion (trophoblast and extraembryonic mesoderm including umbilical cord and vessels), yolk sac, allantois and amniotic fluid (including all components contained therein). Extraembryonic tissue and cells derived therefrom have the same genotype as the developing embryo.
[0037] As used herein, the term “extraembryonic cytokine secreting cells” or “ECS cells” means a population of cells derived from the extraembryonic tissue which have the characteristics of secreting a unique combination of physiologically relevant cytokines in a physiologically relevant temporal manner into the extracellular space or into surrounding culture media and which have not been cultured in the presence of any non-human animal-derived components, making them and cell products derived from them suitable for human clinical use. In one embodiment, the ECS cells secrete at least one cytokine selected from VEGF, angiogenin, PDGF and TGFβ2 and at least one MMP inhibitor selected from TIMP-1 and TIMP-2. In another embodiment, the ECS cells secrete more than one cytokine selected from VEGF, angiogenin, PDGF and TGFβ2 and more than one MMP inhibitor selected from TIMP-1 and TIMP-2. In a preferred embodiment, the ECS cells secrete the cytokines VEGF, angiogenin, PDGF and TGFβ2 and the MMP inhibitors TIMP-1 and TIMP-2. The physiological range of the cytokine or cytokines in the unique combination is as follows: ˜5-16 ng/mL for VEGF, ˜3.5-4.5 ng/mL for angiogenin, ˜100-165 pg/mL for PDGF, ˜2.5-2.7 ng/mL for TGFβ 2 , ˜0.68 μg mL for TIMP-1 and ˜1.04 μg/mL for TIMP-2. ECS cells may be selected from populations of cells and compositions described in this application and in US2003/0235563, US2004/0161419, US2005/0124003, U.S. Provisional Application Nos. 60/666,949, 60/699,257, 60/742,067, 60/813,759, U.S. application Ser. No. 11/333,849, U.S. application Ser. No. 11/392,892, PCTUS06/011392, US2006/0078993, PCT/US00/40052, U.S. Pat. No. 7,045,148, US2004/0048372, and US2003/0032179, the contents of which are incorporated herein by reference in their entirety.
[0038] As used herein, the term “Amnion-derived Multipotent Progenitor cell” or “AMP cell” means a specific population of ECS cells that are epithelial cells derived from the amnion. In addition to the characteristics described above for ECS cells, AMP cells have the following characteristics. They have not been cultured in the presence of any non-human animal-derived components, making them and cell products derived from them suitable for human clinical use. They grow without feeder layers, do not express the protein telomerase and are non-tumorigenic. AMP cells do not express the hematopoietic cell markers CD34 and CD45 protein. The absence of CD34 and CD45 positive cells in this population indicates the isolates are not contaminated with hematopoietic stem cells such as umbilical cord blood or embryonic fibroblasts. Virtually 100% of the cells react with antibodies to low molecular weight cytokeratins, confirming their epithelial nature. Freshly isolated amnion epithelial cells, from which AMP cells are derived, will not react with antibodies to the stem/progenitor cell markers c-kit (CD117) and Thy-1 (CD90). AMP cells will not react with antibodies to the stem/progenitor cell markers c-kit (CD117). Several procedures used to obtain cells from full term or pre-term placenta are known in the art (see, for example, US 2004/0110287; Anker et al., 2005, Stem Cells 22:1338-1345; Ramkumar et al., 1995, Am. J. Ob. Gyn. 172:493-500). However, the methods used herein provide improved compositions and populations of cells. AMP cells have previously been described as “amnion-derived cells” (see U.S. Provisional Application Nos. 60/666,949, 60/699,257, 60/742,067, U.S. Provisional Application Nos. 60/813,759, U.S. application Ser. No. 11/333,849, U.S. application Ser. No. 11/392,892, and PCTUS06/011392, each of which is incorporated herein in its entirety).
[0039] By the term “animal-free” when referring to compositions, growth conditions, culture media, etc. described herein, is meant that no non-human animal-derived components, such as animal-derived serum, protein, carbohydrate, lipid, nucleic acid, vitamin, co-enzyme, etc., are used in the preparation, growth, culturing, expansion, or formulation of the composition or process. Only human-derived components may be used in the preparation, growth, culturing, expansion, or formulation of the composition or process.
[0040] By the term “expanded”, in reference to cell compositions, means that the cell population constitutes a significantly higher concentration of cells than is obtained using previous methods. For example, the level of cells per gram of amniotic tissue in expanded compositions of AMP cells is at least 50 and up to 150 fold higher than the number of cells in the primary culture after 5 passages, as compared to about a 20 fold increase in such cells using previous methods. In another example, the level of cells per gram of amniotic tissue in expanded compositions of AMP cells is at least 30 and up to 100 fold higher than the number of cells in the primary culture after 3 passages. Accordingly, an “expanded” population has at least a 2 fold, and up to a 10 fold, improvement in cell numbers per gram of amniotic tissue over previous methods. The term “expanded” is meant to cover only those situations in which a person has intervened to elevate the number of the cells.
[0041] As used herein, the term “passage” means a cell culture technique in which cells growing in culture that have attained confluence or are close to confluence in a tissue culture vessel are removed from the vessel, diluted with fresh culture media (i.e. diluted 1:5) and placed into a new tissue culture vessel to allow for their continued growth and viability. For example, cells isolated from the amnion are referred to as primary cells. Such cells are expanded in culture by being grown in the growth medium described herein. When such primary cells are subcultured, each round of subculturing is referred to as a passage. As used herein, “primary culture” means the freshly isolated cell population.
[0042] As used herein, the terms “a” or “an” means one or more; at least one.
[0043] “Treatment,” “treat,” or “treating,” as used herein covers any treatment of a disease or condition of a mammal, particularly a human, and includes: (a) preventing the disease or condition from occurring in a subject which may be predisposed to the disease or condition but has not yet been diagnosed as having it; (b) inhibiting the disease or condition, i.e., arresting its development; (c) relieving and or ameliorating the disease or condition, i.e., causing regression of the disease or condition; or (d) curing the disease or condition, i.e., stopping its development or progression. The population of subjects treated by the methods of the invention includes subjects suffering from the undesirable condition or disease, as well as subjects at risk for development of the condition or disease.
DETAILED DESCRIPTION
[0044] In accordance with the present invention there may be employed conventional molecular biology, microbiology, and recombinant DNA techniques within the skill of the art. Such techniques are explained fully in the literature. See, e.g., Sambrook et al, 2001, “Molecular Cloning: A Laboratory Manual”; Ausubel, ed., 2007, “Current Protocols in Molecular Biology” Volumes I-IV; Celis, ed., 2005, “Cell Biology: A Laboratory Handbook” Volumes I-III; Coligan, ed., 2007, “Current Protocols in Immunology”; Gait ed., 1984, “Oligonucleotide Synthesis”; Hames & Higgins eds., 1991, “Nucleic Acid Hybridization”; Hames & Higgins, eds., 1985,“Transcription And Translation: A Practical Approach”; Freshney, ed., 2006, “Animal Cell Culture” 2 nd Ed.; IRL Press, 1986, “Immobilized Cells And Enzymes”; Perbal, 1984, “A Practical Guide To Molecular Cloning.”
[0045] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either both of those included limits are also included in the invention.
[0046] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described.
[0047] It must be noted that as used herein and in the appended claims, the singular forms “a,” “and” and “the” include plural references unless the context clearly dictates otherwise.
[0048] Obtaining and Culturing of Cells
[0049] Various methods for isolating cells from the amnion of the placenta, which may then be used to obtain AEC, ADC and AMP cells and subsequently produce the dedifferentiated and reprogrammed cells of the instant invention, are described in the art (see, for example, US2003/0235563, US2004/0161419, US2005/0124003, U.S. Provisional Application Nos. 60/666,949, 60/699,257, 60/742,067, 60/813,759, U.S. application Ser. No. 11/333,849, U.S. application Ser. No. 11/392,892, PCTUS06/011392, US2006/0078993, PCT/US00/40052, U.S. Pat. No. 7,045,148, US2004/0048372, and US2003/0032179).
[0050] In particular, AMP cell compositions are prepared using the steps of a) recovery of the amnion from the placenta, b) dissociation of the cells from the amniotic membrane, c) culturing of the cells in a basal medium with the addition of a naturally derived or recombinantly produced human protein; d) selecting AMP cells from the cell culture, and optionally e) further proliferation of the cells, optionally using additional additives and/or growth factors. Details are contained in US Publication No. 2006-0222634-A1, which is incorporated herein by reference.
[0051] AMP cells are cultured as follows: The AMP cells are cultured in a basal medium. Such medium includes, but is not limited to, Epilife (Cascade Biologicals), Opti-pro, VP-SFM, IMDM, Advanced DMEM, K/O DMEM, 293 SFM II (all made by Gibco; Invitrogen), HPGM, Pro 293S-CDM, Pro 293A-CDM, UltraMDCK, (all made by Cambrex), Stemline I and Stemline II (both made by Sigma-Aldrich), DMEM, DMEM/F-12, Ham's F12, M199, and other comparable basal media. Such media may either contain human protein or be supplemented with human protein. As used herein a “human protein” is one that is produced naturally or one that is produced using recombinant technology. “Human protein” also is meant to include a human fluid or derivative or preparation thereof, such as human serum or amniotic fluid, which contains human protein. Details on this procedure are contained in US Publication No. 2006-0222634-A1, which is incorporated herein by reference.
[0052] In a most preferred embodiment, the cells are cultured using a system that is free of animal products to avoid xeno-contamination. In this embodiment, the culture medium is IMDM, Stemline I or II, Opti-pro, or DMEM, with human albumin added up to concentrations of 10%. The invention further contemplates the use of any of the above basal media wherein animal-derived proteins are replaced with recombinant human proteins and animal-derived serum, such as BSA, is replaced with human albumin. In preferred embodiments, the media is serum-free in addition to being animal-free. Details on this procedure are contained in US Publication No. 2006-0222634-A1, which is incorporated herein by reference.
[0053] In alternative embodiments, where the use of non-human serum is not precluded, such as for in vitro uses, the culture medium may be supplemented with serum derived from mammals other than humans, in ranges of up to 40%.
[0054] Genes and DNA Constructs
[0055] In accordance with the present invention, AEC, ADC and/or AMP cells may be genetically manipulated such that they comprise one or more pluripotency gene(s) (i.e., Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella) linked to DNA encoding a selectable marker in such a manner that the expression of the selectable marker substantially matches the expression of the pluripotency gene. In one embodiment, the AEC, ADC and/or AMP cells comprise a first pluripotency gene linked to DNA encoding a first selectable marker in such a manner that the expression of the first selectable marker substantially matches the expression of the first pluripotency gene. The AEC, ADC and/or AMP cells may also be engineered to comprise any number of pluripotency genes, each respectively linked to a distinct selectable marker. The AEC, ADC and/or AMP cells may also be engineered to have one or more pluripotency gene expressed as a transgene under an inducible promoter. In a preferred embodiment, the AEC, ADC and/or AMP cells are genetically manipulated to comprise the Oct4, Sox2, Klf4, and c-Myc pluripotency genes.
[0056] The selectable marker may be linked to an appropriate pluripotency gene such that the expression of the selectable marker substantially matches the expression of the pluripotency gene i.e., the selectable marker and the pluripotency gene are co-expressed, although it is not necessary that their relative expression levels be the same or even similar. It is only necessary that the AEC, ADC and/or AMP cells in which a pluripotency gene is activated will also express the selectable marker at a level sufficient to confer a selectable phenotype on the reprogrammed cells. Skilled artisans are familiar with selectable markers commonly used in genetic engineering strategies.
[0057] The DNA encoding a selectable marker may be inserted downstream from the end of the open reading frame (ORF) encoding the desired pluripotency gene, anywhere between the last nucleotide of the ORF and the first nucleotide of the polyadenylation site. An internal ribosome entry site (IRES) may be placed in front of the DNA encoding the selectable marker. Alternatively, the DNA encoding a selectable marker may be inserted anywhere within the ORF of the desired pluripotency gene, downstream of the promoter, with a termination signal. An internal ribosome entry site (IRES) may be placed in front of the DNA encoding the selectable marker. Skilled molecular biologists recognize that many other suitable constructs are possible and all are contemplated by the methods of the invention.
[0058] Methods for Reprogramming AEC, ADC and/or AMP Cells
[0059] In general, the methods for reprogramming AEC, ADC and/or AMP cells comprise treating the cells with an agent capable of effecting dedifferentiation and reprogramming. Such treatment may involve contacting the cells with an agent which alters chromatin structure (i.e., a demethylating agent), or may involve transfecting the cells with one or more pluripotency gene(s) (as described above), or both. The above two treatments may be concurrent or sequential. Reprogrammed AEC, ADC and AMP cells (termed AEC R , ADC R and AMP R cells) are identified by selecting for cells that express the appropriate selectable marker. In addition, AEC R , ADC R and/or AMP R cells are assessed for the presence of pluripotency characteristics. The presence of pluripotency characteristics indicates that the AEC, ADC and/or AMP cells have been reprogrammed to a pluripotent status.
[0060] The term “pluripotency characteristics”, as used herein, refers to many characteristics associated with pluripotency, including but not limited to, for example, the ability to differentiate into all types of cells and having a gene expression pattern distinct for a pluripotent cell, including for example expression of pluripotency genes (i.e., Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella), expression of other ES cell markers (i.e., SSEA-1, SSEA-3, SSEA-4, elevated Alkaline Phosphatase levels, nestin, AC133, Tcf4 or Cdx1), lack of expression of differentiation markers, in some instances teratoma formation, embryoid body formation (i.e., aggregates of cells derived from embryonic stem cells), etc. Self-renewing capacity, marked by induction of telomerase activity, is another pluripotency characteristic that can be assessed. Functional assays of the AEC R , ADC R and/or AMP R cells may be performed by introducing the cells into blastocysts and determining whether the cells are capable of forming some cell types, wherein they are multipotent; if the AEC R , ADC R and/or AMP R cells are capable of forming all cell types of the body including germ cells, they are pluripotent.
[0061] AEC, ADC and/or AMP cells may be reprogrammed to gain a complete set of the pluripotency characteristics. Alternatively, AEC, ADC and/or AMP cells may be reprogrammed to gain only a subset of the pluripotency characteristics.
[0062] Expression of an exogenous pluripotency gene may occur in several ways. In one embodiment, the exogenously introduced pluripotency gene may be expressed from a chromosomal locus different from the endogenous chromosomal locus of the pluripotency gene. Such chromosomal locus may be a locus with open chromatin structure and contain a gene dispensable for the cell. An exemplary chromosomal locus is the human ROSA 26 locus (see, for example, Irion, et al., Nature Biotechnology 25, 1477-1482 (2007). The exogenously introduced pluripotency gene may be expressed from an inducible promoter such that their expression can be regulated as desired. The term “inducible promoter”, as used herein, refers to a promoter that, in the absence of an inducer (such as a chemical and/or biological agent), does not direct expression, or directs low levels of expression of an operably linked gene (including cDNA), and, in response to an inducer, its ability to direct expression is enhanced. Skilled artisans are familiar with inducible promoters and their application.
[0063] In an alternative embodiment, the exogenously introduced pluripotency gene may be transiently transfected into AEC, ADC and/or AMP cells, either individually or as part of a cDNA expression library, such library prepared from pluripotent cells. The cDNA library is prepared by conventional techniques familiar to skilled artisans.
[0064] Several agents may be used in the methods which may cause chromatin to take on a more open structure, which is more permissive for gene expression. For example, DNA methylation and histone acetylation are two known events that alter chromatin toward a more closed structure. Loss of methylation by genetic deletion of the DNA methylation enzyme Dnmt1 in fibroblasts results in reactivation of endogenous Oct4 gene. See J. Biol. Chem. 277: 34521-30, 2002; and Bergman and Mostoslaysky, Biol. Chem. 1990. Thus, DNA methylation inhibitors and histone deacetylation inhibitors are two classes of agents that may be used in the methods of the invention. Exemplary demethylation agents include 5-aza-cytidine or 5-azadeoxycytidine and deacetylation agents include trichostatin A, trapoxin B, depsipeptides, benzamides, electrophilic ketones, phenylbutyrate or valproic acid.
EXAMPLES
[0065] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the methods and compositions of the invention, and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, molecular weight is average molecular weight, temperature is in degrees Centigrade, and pressure is at or near atmospheric.
Example 1
Preparation of AMP Cell Compositions
[0066] Recovery of AMP cells—Amnion epithelial cells were dissociated from starting amniotic membrane using the dissociation agent PXXIII. The average weight range of an amnion was 18-27 g. The number of cells recovered per g of amnion was about 10-15×10 6 for dissociation with PXXIII.
[0067] Method of selecting AMP cells: Amnion epithelial cells were isolated from the amnion and frozen in liquid nitrogen. Once thawed, the cells were plated and after ˜2 - 3 days in culture non-adherent cells were removed and the adherent cells were kept. The adherent cells represent about 30% of the plated cells. This attachment to plastic tissue culture vessel is the selection method used to obtain the desired population of AMP cells. Adherent and non-adherent cells appear to have a similar cell surface marker expression profiles but the adherent AMP cells have greater viability and are the desired population of cells. Selected AMP cells were cultured until they reached ˜120,000-300,000 cells/cm 2 . At this point, the cultures were confluent. Suitable cell cultures will reach this number of cells between ˜5-14 days. Attaining this criterion is an indicator of the proliferative potential of the AMP cells and cells that do not achieve this criterion are not selected for further analysis and use. Once the AMP cells reach ˜120,000-300,000 cells/cm 2 , they were collected and cryopreserved. This collection time point is called p0.
Example 2
DNA Constructs for Introducing Pluripotency Genes Into Cells
[0068] DNA constructs containing pluripotency genes are constructed. The constructs may be transfection plasmids or they may be viral vectors.
[0069] The DNA constructs may contain one pluripotency gene (i.e., any of one Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella) or they may contain one, two, three, four, five, six or seven pluripotency genes. Many combinations of the different pluripotency genes is also contemplated. For example, a DNA construct may contain Oct4 and Sox2; Klf4 and Stella; Oct4, Sox2 and Klf4, etc. A preferred DNA construct contains Oct4, Sox2, Klf4, and c-Myc. Any and all combinations of pluripotency genes in DNA constructs are contemplated by the invention.
[0070] To construct the DNA constructs, the cDNAs for the pluripotency genes can be obtained from various sources. For example, the cDNAs may be purchased from GeneCopoeia, Inc., 18520 Amaranth Drive, Germantown, Md., 20874 (www.genecopoeia.com) using the following product IDs: Oct4 Product ID T2820; Sox2 Product ID T2547; Klf4 Product ID Q0453; nanog Product ID W2005; Stella Product ID Y4255. c-Myc can be obtained from OriGene Technologies, Inc., 6 Taft Court, Suite 100, Rockville, Md., 20850 (www.origene.com) catalog # SC107923.
[0071] Viral vectors can be obtained from several sources as well. For example, lentiviral packaging kits can be obtained from GeneCopoeia, Inc., 18520 Amaranth Drive, Germantown, Md., 20874 (www.genecopoeia.com), Product No. PLv-PK-01. Retroviral packaging kits can be obtained from Fischer Scientific, Inc., 2000 Park Lane Drive, Pittsburgh, Pa. 15275, Catalog No. 6160 or 6161. Adenoviral expression kits can be obtained from Invitrogen, Inc., Carlsbad, Calif. 92008 (www.invitrogen.com) SKU #K4930-00.
[0072] Skilled artisans are familiar with standard molecular biology protocols for the construction of DNA constructs. Any standard methodology for the introduction of DNA into cells is suitable for use in the methods of the invention, including calcium phosphate precipitation, lipofection, electroporation, infection with viral vectors, etc.
Example 3
Culture Method for Producing Pluripotent Cells or Maintaining Pluripotency of Cells
[0073] Specific culture methods are suitable for producing pluripotent cells. For example, the method described by Brons, et al (Nature 2007, 448:191-195) or the method described by Tesar et al (Nature 2007, 448:196-199) is suitable for producing pluripotent cells or for maintaining pluripotency of cells. Cells suitable for use in such methods include the AEC R , ADC R and/or AMP R cells described herein, or other reprogrammed or induced pluripotent cells known to skilled artisans, for examples, those described by Yamanaka, S. (Philos Trans R Soc Lond B Biol Sci 2008 363 (1500):2079-87); Yamanaka, S. (Cell Prolif 2008 Suppl 1:51-6), Okita, K., et al., (Science 2008 322 (5903) 949-53, Epub 2008 Oct. 9); Park, I. H., et al., (Nature 451:141-6, 2008), Yu, J., et al., (Science 318:1917-20, 2007); Takahashi, K., et al., (Nat Protoc 2007 2 (12):3081-9); Oliveri, R. S. (Regen Med 2007 2 (5):795-816); Alberio, R., et al., (Reproduction 2006 132 (5):709-20); and U.S. Publication No. 20080280362, each of which is incorporated herein by reference. Naturally occurring pluripotent cells such as ES cells and cells derived from a pre-implantation embryo, are also suitable for use in the methods.
Example 4
Analyzing Cells for Pluripotency
[0074] Any number of assays and analyses are used to assess the pluripotency of the AEC R , ADC R and/or AMP R cells. For example, RT-PCR is performed to detect expression of pluripotency genes (i.e., Oct4, Sox2, Klf4, c-Myc, nanog, Lin28, or Stella). FACS is performed to detect the expression of cell surface markers (i.e., SSEA-1, SSEA-3, SSEA-4). AEC R , ADC R and/or AMP R cells are injected into SCID mice to look for teratoma formation. The AEC R , ADC R and/or AMP R cells are cultured to detect embryoid body formation. Self-renewing capacity, marked by induction of telomerase activity, is assessed by RT-PCR. Functional assays of the AEC R , ADC R and/or AMP R cells is performed by introducing the cells into blastocysts and determining whether the cells are capable of forming some cell types.
Example 5
Uses of Reprogrammed Cells
[0075] AEC R , ADC R and AMP R cells are treated with various differentiation media, agents, conditions, etc., to induce them to differentiate down any cellular pathway. For example, the AEC R , ADC R and/or AMP R are exposed to conditions known to effect differentiation of cells arising from all three primary germ layers, the endoderm, mesoderm and ectoderm. The endoderm forms the stomach, the colon, the liver, the pancreas, the urinary bladder, the lining of the urethra, the epithelial parts of trachea, the lungs, the pharynx, the thyroid, the parathyroid, and the intestines. The mesoderm forms: skeletal muscle, the skeleton, the dermis of skin, connective tissue, the urogenital system, the heart, blood (lymph cells), and the spleen. The ectoderm forms: the central nervous system, the lens of the eye, cranial and sensory, the ganglia and nerves, pigment cells, head connective tissues, the epidermis, hair, and mammary glands.
[0076] Such differentiated cells are then used to treat various conditions, for example, diabetes, heart disease, nervous system disease, etc.
[0077] The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims.
[0078] Throughout the specification various publications have been referred to. It is intended that each publication be incorporated by reference in its entirety into this specification. | The invention is directed to methods for reprogramming somatic cells to a less differentiated state. In particular, the invention is directed to methods for reprogramming amnion epithelial cells (AEC) including amnion-derived cells (ADC) and Amnion-derived Multipotent Progenitor cells (AMP cells) to a less differentiated state. The invention is further directed to compositions comprising reprogrammed AEC, ADC and AMP cells, and uses thereof. | 2 |
FIELD OF THE INVENTION
The present invention concerns a high power optical amplification system and method. More particularly, the invention concerns an optical amplifier based on solid-state gain medium, such as doped glasses or crystals and a method for increasing output energy without transverse lasing.
RELATED ART
There are mainly two types of solid-state amplification systems for high energy, ultra short pulses: regenerative amplifiers and multipass amplifiers. A regenerative amplifier comprises an optical system forming a resonant cavity that includes the gain medium. In a regenerative amplifier, the number N of passes of the optical beam through the gain medium is very important (N>10). In contrast, a multipass amplifier generally comprises a thin, high gain medium and an optical system that allows only a limited number of passes (N=2−8) of the optical beam to be amplified through the gain medium. The present invention concerns a multipass non-regenerative amplification system and method.
Multipass amplifiers are the core of solid-state laser systems. Such lasers are required with increasing energy, power and shorter pulse duration. In particular, there is a need for high power lasers, in the Petawatt range. There is also a need for ultrashort pulse lasers, with high repetition rate and energy level around few tens of Joules per pulse.
The scaling of high energy laser for the production of very high intensity pulses requires large aperture solid-state gain medium. For example, a Ti-Sapphire laser uses one or several Titanium doped sapphire crystals. The largest Ti:sapphire crystals available are cylinders or disks of 10 cm diameter and a few centimeters length (1-5 cm).
Briefly, the optical amplification process is based on spontaneous emission of a gain medium when the amplifying medium is pumped optically. An optical amplifier generally comprises a non linear crystal that is pumped at a pump wavelength λ P different from the emission wavelength λ e . The optical pumping is generally longitudinal, along the crystal cylinder axis and in the same direction as the amplified beam propagation (propagative pumping) and/or in the opposite direction (contra-propagative pumping).
There are several solutions for increasing the output beam energy: increasing the pump power, increasing the gain-medium surface exposed to the pump beam, and/or the gain-medium size.
Larger Ti:Sa crystals are used for increasing the pump absorption and the overall gain of the amplifier.
Bonlie et al. (Production of >10 21 W/cm 2 from a large aperture Ti:sapphire laser system, Appl. Phys. B 70, 2000, S155-S160) describe a laser system using two Ti: sapphire amplifiers in “V” configurations, wherein the pulsed beam double-passes the first Ti:sapphire amplifier, and then double-passes the 2 nd Ti:sapphire amplifier. The two amplifiers thus amplify the pulse sequentially, the pulse amplified by the first amplifier being injected into the second amplifier.
However, Bonlie et al. disclose also that adverse effects of transverse lasing occur as crystal diameter and pump power increase. Transverse lasing is due to the formation of “laser cavities” inside the crystal and induced by the pumping beam ( 3 , 4 ), as represented schematically FIG. 1 . Total internal reflections (R=1) of the pumping beam on the crystal edges can create parasitic transverse lasing ( 5 ), that decrease the output beam energy.
For a cylindrical crystal 1 , cavities are created in a plane transverse to the optical axis ( 2 ). In order to avoid multiple internal reflections, the input and output plane faces of crystal ( 1 ) are coated with an anti-reflection coating. However, pumping beams with an angle of incidence above 36 degrees on the anti-reflection coated faces are totally reflected. The optical losses (diffusion and absorption) depend on the index of reflection of the crystal and of the outside medium. Transverse lasing occurs depending on the product of the optical losses by the volume gain.
Transverse gain, G t (0), at the crystal surface for a cavity as represented in FIG. 1 is given by the following formula:
G
0
t
(
0
)
=
exp
(
-
σ
e
J
0
μ
c
Φλ
p
ln
(
1
-
A
λ
p
)
h
c
l
[
2
-
A
λ
p
]
)
(
1
)
Where λ p is the pump wavelength, A λp is the crystal absorption at pump wavelength, σ e is the amplification cross section at emission wavelength λ e , J 0 pump fluence on a crystal face, φ the pump beam diameter and μ c the coupling efficiency, that defines non radiative losses (depending on the crystal temperature). h is the planck constant (6.6 10 −34 J·s), c is the speed of light in vacuum (3 10 8 m/s), and/the crystal length.
We derive from equation (1) that, for a constant pump fluence, transverse gain G t increases exponentially with the pump beam diameter φ, whereas the extracted energy only increases quadratically.
The problem of transverse lasing thus becomes a major concern as higher energy output beams are required.
Bonlie et al. disclose the use of an edge cladding around the Ti:sapphire crystal, said cladding comprising a doped polymer with an absorber for reducing transverse lasing. However, the aging of polymers and absorbing materials when exposed to high repetition laser pulses is unknown.
Besides, the use of increasingly larger Ti:sapphire single crystal (above 10 cm diameter) generates several issues. The quality requirements, availability and cost of such large size single crystal turn into reliability issues for the high energy laser chain.
BRIEF SUMMARY OF THE INVENTION
The object of the invention is to provide high power amplification system and method with limited transverse lasing. Another goal of the invention is to provide a stable, reliable and cost-effective amplification system and method.
More precisely, the invention concerns a high power solid-state non-regenerative optical amplification system for amplifying a pulsed optical beam, said amplification system comprising:
a first optical amplification crystal (C 1 ) and a second optical amplification crystal (C 2 ) for amplifying said optical beam; optical pumping means for longitudinal pumping amplification crystals (C 1 , C 2 ); reflective optical means suitable for reflecting the optical beam so that the optical beam makes a total number of N sequential passes through said amplification crystals (C 1 , C 2 ), wherein N is an integer and N≧3.
According to the invention, the reflective optical means are placed in a configuration suitable for alternatively interleaving the sequential optical beam passes through the 1 st crystal (C 1 ) and through the 2 nd crystal (C 2 ).
According to an embodiment of the invention, the reflective optical means are arranged so that the optical beam makes multiple passes through the two crystals (C 1 , C 2 ) including sequentially:
at least a first pass through 1 st amplification crystal (C 1 ), at least a first pass through 2 nd amplification crystal (C 2 ), at least another pass through 1 st amplification crystal (C 1 ), and at least another pass through 2 nd amplification crystal (C 2 ).
According to a preferred embodiment of the invention, the reflective optical means are placed in “V” configuration so that the optical beam makes sequentially:
a first pass through 1 st amplification crystal (C 1 ), a double pass through 2 nd amplification crystal (C 2 ), a double pass through 1 st amplification crystal (C 1 ), and a double pass through 2 nd amplification crystal (C 2 ).
Various embodiments the invention also concern the following features, that can be considered alone or according to all possible technical combinations and each bring specific advantages:
the total number N of passes through said amplification crystals (C 1 , C 2 ) is lower than 10; said amplification crystals (C 1 , C 2 ) are Titanium doped sapphire crystals or Nd:glass; said amplification crystals (C 1 , C 2 ) have the same diameter Φ and the to same thickness L; said amplification crystals (C 1 , C 2 ) have different sizes; the maximum transverse gain G t in the amplification crystals (C 1 , C 2 ) is lower than 50.
The invention also concerns a solid-state laser comprising an amplification system according to the invention.
In particular, the invention concerns a Petawatt laser comprising an amplification system according to the invention.
The invention also concerns a method for amplifying a pulsed optical beam in a two-crystals non-regenerative amplification system according to the invention and comprising the following steps:
longitudinally pumping two optical amplification crystals (C 1 , C 2 ); injecting said optical beam said 1 st amplification crystal (C 1 ); reflecting said optical beam for multiple sequential passes through the two optical amplification crystals (C 1 , C 2 ), wherein the multiple pass step includes alternatively interleaving the optical beam passes through the 1 st crystal (C 1 ) and through the 2 nd crystal (C 2 ) by means of the optical reflective system.
According to a preferred embodiment of the method of the invention, the multiple pass step comprises the following steps:
at least a first pass through 1 st amplification crystal (C 1 ), at least a first pass through 2 nd amplification crystal (C 2 ), at least another pass through 1 st amplification crystal (C 1 ), and at least another pass through 2 nd amplification crystal (C 2 ).
According to a preferred method, the amplification process comprises the following steps:
a first pass through 1 st amplification crystal (C 1 ), a double pass through 2 nd amplification crystal (C 2 ), a double pass through 1 st amplification crystal (C 1 ), and a double pass through 2 nd amplification crystal (C 2 ).
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
The following description is given as an example of the invention but can have various embodiments that will be better understood when referring to the following figures:
FIG. 1 represents schematically a cross-section view of a Ti:sapphire crystal and of transverse lasing induced by pump beams in the crystal;
FIG. 2 represents schematically a prior art multipass amplification system comprising two amplification crystals, each in a bow-tie configuration;
FIG. 3 represents an example of energy amplified in a multipass system as represented in FIG. 2 as a function of time, and for the successive passes though the 1 st and 2 nd crystal;
FIG. 4 represents schematically a first embodiment of a multipass amplifier according to the invention;
FIG. 5 represents a simulation of energy build-up as a function of time and as a function of interleaved passes through the 1 st and 2 nd crystals;
FIG. 6 represents schematically another embodiment of the multipass amplifier according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-section view of a large aperture amplification crystal ( 1 ) with longitudinal propagative and contra-propagative pump beams ( 3 , 4 ). The crystal ( 1 ) is generally a straight cylinder with disk shaped faces of diameter Φ and length L and with an optical axis ( 2 ). The amplification crystal ( 1 ) is pumped longitudinally by one or two longitudinal pump beams ( 3 , 4 ) for pumping the crystal through the two flat faces. Fluorescence beam can propagate inside the crystal and be reflected on the flat faces and/or the outer surface. Losses can occur at the interfaces due to diffusion for example. However, for Ti:Sa crystal (refractive index n=1.76), if the angle of incidence of the beam is above 36 degrees, the beam is totally reflected (reflection coefficient R=1) and transverse lasing ( 5 ) can occur inside crystal ( 1 ).
For reference and future comparison with a double crystal multipass system, and with an embodiment of the invention, a prior art single crystal amplification system has the following operating parameters. The maximum energy pump is set at 160 J and the maximum operating fluences at 1 J·cm −2 for a crystal having a diameter Φ of 15 cm, a length L of 3 cm and 90% absorption at λ P =532 nm. It is necessary to makes N=6 passes through this single crystal for reaching saturation and amplification of the infrared (800 nm) pulse. In such conditions, the amplifier parameters are as follows:
Fluence at λ p =532 nm:0.95 J·cm −2 Fluence at 800 nm:0.7 J·cm −2 Output energy after 6 passes:67 J Pump beam diameter at λ p (532 nm):12 cm Optical beam diameter at 800 nm:11.5 cm Maximum transverse gain G t :400
The transverse gain for a single crystal amplifier is extremely large. The above example confirms that transverse lasing becomes a major issue with crystal dimensions (Φ and L) and with the beam fluence.
FIG. 2 represents a prior art amplification system comprising two amplifiers (A 1 , A 2 ) each schematically surrounded by a dashed line. Optical pumping means are not represented on FIG. 2 . Pumping beams are assumed to be conventional longitudinal propagative and contra-propagative beams. Each amplifier (A 1 , A 2 ) comprises an amplification crystal (C 1 , C 2 ) and an optical system for multipass amplification through each crystal.
Considering the 1 st amplifier A 1 , the optical system is a reflective optical system comprising mirrors M 1 -M 7 . The mirrors are arranged in a well-known bow-tie configuration, for enabling the optical beam to pass N i times through amplification crystal 1 . The input beam S in is directed by mirror M 1 through the first crystal (C 1 ). S 1 represents the optical beam S in amplified after the first pass through first crystal (C 1 ). S 1 propagates and is reflected successively by mirrors M 2 and M 3 towards the first crystal (C 1 ) for a second pass. After passing through (C 1 ), the beam S 1 is amplified into S 2 . S 2 is reflected by mirrors M 4 and M 5 and directed for a third pass through first crystal (C 1 ). After the third pass, amplified beam S 3 is reflected by mirrors M 6 and M 7 and directed for a fourth pass through first crystal (C 1 ) and amplified into S 4 beam. In the example of FIG. 2 , the optical beam is amplified successively by N 1 =4 passes through crystal (C 1 ). Multiple passes enable to reach saturation inside crystal (C 1 ) and thus maximum amplification.
An intermediate reflective optical system (mirrors M 8 -M 10 ) transfers the optical beam amplified by the 1 st amplifier A 1 and injects it into the 2 nd amplifier (A 2 ). S 4 beam exits out of Amplifier 1 and is directed by the mirrors M 8 , M 9 and M 10 towards a second amplification stage.
Similarly to the first amplifier A 1 , the second amplifier A 2 comprises a second amplification crystal (C 2 ) and a reflective optical system (mirrors M 11 -M 17 ), for passing the optical beam N 2 times through crystal (C 2 ). S 4 beam is reflected by mirror M 11 and directed for a first pass through second crystal C 2 . After passing through (C 2 ), the beam S 4 is amplified into S 5 . Amplified beam S 5 is reflected by mirrors M 12 and M 13 and directed for a second pass through crystal (C 2 ). After the second pass through C 2 , amplified beam S 6 is reflected by mirrors M 14 and M 15 and directed for a third pass through second crystal (C 2 ) and amplified into S 7 beam. Beam S 7 is reflected by mirrors M 16 and M 17 and directed for a fourth pass through second crystal (C 2 ) and amplified into S 8 beam. Beam S 8 is thus amplified successively four times through first crystal C 1 and then four times through second crystal C 2 .
As a reference for future comparison with an embodiment of the invention, a prior art system as represented on FIG. 2 comprises two Titanium:sapphire crystals of same length (3 cm) and absorption 90% at 532 nm.
The 1 st amplifier (A 1 ) parameters are as follows:
Crystal Diameter Φ 1 :7.5 cm Pump beam diameter at λ p (532 nm):6 cm Optical beam diameter at 800 nm:5.5 cm Pump energy:40 J/Fluence at λ p (532 nm):0.94 J·cm −2 Input energy at 800 nm:5 J/Maximum fluence:0.9 J·cm −2 Output energy after 4 passes:20 J Maximum transverse gain G t :100
The 2 nd amplifier (A 2 ) parameters are as follows:
Crystal Diameter Φ 2 :12.5 cm Pump beam diameter at λ p (532 nm):10 cm Optical beam diameter at 800 nm:9.5 cm Pump energy (532 nm):120 J/Fluence at λ p :1 J·cm −2 Input energy at 800 nm:20 J/Maximum fluence:1 J·cm −2 Output energy after 4 passes:67.5 J Maximum transverse gain G t :200
FIG. 3 represents the progressive amplification of the optical beam in a prior art two crystals amplification system, with above parameters, wherein the optical beam makes 4 passes inside each amplification crystal (total N=8). The lower curve corresponds to A 1 amplification, and the upper curve to A 2 amplification. The input energy in A 1 is 5 J at 800 nm. The output energy of A 1 is 20 J after 4 passes. The optical beam amplified by A 1 is the injected into A 2 and amplified again. The output energy after 4 passes through A 2 is 67.5 J. In the example represented FIG. 3 , we observe a progressive saturation of the energy for each crystal, and the 4 th path in each crystal appears unnecessary.
In summary, prior art multipass amplification system, as illustrated in FIGS. 2-3 comprise two crystals for serial amplification of the optical beam, up to the maximum gain corresponding to the sum of the gains of the two crystals (C 1 , C 2 ).
FIG. 4 represents schematically a first embodiment of a multipass amplifier according to the invention. The amplification system ( 100 ) comprises two amplification crystals (C 1 , C 2 ). Optical pumping means are not represented on FIG. 4 . Pumping beams are assumed to be conventional longitudinal propagative and contra-propagative beams. The amplification system also comprises an optical system (M′ 1 -M′ 13 ) for multipass amplification through the two crystals (C 1 , C 2 ). However, in contrast with prior art multiple crystals amplification system, the optical beam does not follow a serial amplification through the different crystals, with a first amplification in a first crystal and then sequentially a second amplification in the 2 nd crystal.
As evidenced on FIG. 4 , the input optical beam S′ i makes a first pass through the 1 st amplification crystal (C 1 ), and forms an amplified beam S′ 1 . Mirrors M′ 2 -M′ 3 inject the S′ 1 beam into the second amplification crystal (C 2 ). After a first pass through 2 nd amplification crystal (C 2 ) the amplified beam is labelled S′ 2 . In the embodiment of FIG. 4 , the amplified beam S′ 2 is reflected by mirrors M′ 4 -M′ 5 for passing again through the 2 nd crystal (C 2 ) and forms amplified beam S′ 3 . Then, the amplified beam S′ 3 is injected using mirrors M′ 6 -M′ 7 into the first crystal (C 1 ) for another pass through the 1 st crystal (C 1 ). Mirrors M′ 8 -M′ 9 inject amplified beam S′ 4 into the 1 st crystal for a 3 rd pass through this 1 st crystal (C 1 ). Mirrors M′ 10 -M′ 11 inject amplified beam S′ 5 into the 2 nd crystal (C 2 ) for a 3 rd pass, thus forming amplified beam S′ 6 . Mirrors M′ 12 -M′ 13 fold amplified beam S′ 6 and inject it for a fourth pass through crystal (C 2 ). Mirror M′ 14 extracts the amplified S′ 7 beam out of amplification system ( 100 ).
In summary, the optical beam makes a total of N=7 passes through the amplification crystals, including three passes through crystal (C 1 ) and four passes through crystal (C 2 ). In contrast to prior art multi-crystal amplification systems, the passes through the different crystals (C 1 , C 2 ) are interleaved. More precisely, the sequential passes through the first crystal C 1 and through the second crystal C 2 are alternatively interleaved. In the above example, after the 1 st pass through the 1 st crystal (C 1 ), following passes are double-passes alternatively though the 2 nd and 1 st crystal.
Alternatively, the 1 st pass in C 1 can be a double pass.
In an example, the length of each crystal (C 1 , C 2 ) is 3 cm and their diameter 12.5 cm. The pump beam wavelength is 532 nm. The crystal absorption at 532 nm is 90%. The pump beam diameter is 10 cm, and the diameter of the optical beam (to be amplified) is 9.5 cm. The overall pump energy is 80 J for each crystal, and the pump fluence at 532 nm is 0.7 J·cm −2 . The input optical beam energy is 5 J at 800 nm, and the maximum fluence is 0.92 J·cm −2 . The output energy after 8 passes is 68.3 J. The maximum transverse gain is G t =40 in each crystal (C 1 , C 2 ).
Crystal Diameter Φ 1 =Φ 2 :12.5 cm Pump beam diameter at λ p (532 nm):10 cm Optical beam diameter at 800 nm:9.5 cm Pump energy (532 nm):80 J/Fluence at λ p :0.7 J·cm −2 Input energy at 800 nm:5 J/Maximum fluence:0.92 J·cm −2 Output energy after 8 passes (total):68.3 J Maximum transverse gain G t :40
FIG. 5 represents the progressive amplification of the optical beam in an example corresponding to the configuration of FIG. 4 using the above operating parameters.
We observe a regular amplification, almost linear by steps, during the interleaved passes through the 1 st and 2 nd amplification crystals C 1 and C 2 .
The energy at the output of the amplification system represented in FIG. 5 is 68.7 J for 5 J input energy, which corresponds approximately to the same energy levels as observed for the system presented in FIGS. 2-3 . The overall gain of the prior art system and of the embodiment of the invention are thus similar.
However, as compared to prior art system, the transverse gain inside both amplification crystals of the preferred embodiment of the invention is much lower: G t =40 instead of 200.
In addition, the pump density is also lower on both crystals (0.7 J·cm −2 , instead of 1 J·cm −2 ), resulting in a higher transverse lasing threshold, better extraction, and in an improved crystal protection against damage.
FIG. 6 represents schematically another embodiment of the invention. In the embodiment of FIG. 6 , the beam makes single passes alternatively through the first crystal (C 1 ) and through the second crystal (C 2 ).
As evidenced on FIG. 6 , the input optical beam S′ i is reflected by mirror M′ 1 , makes a first pass through the 1 st amplification crystal (C 1 ), and forms an amplified beam S′ 1 . Mirrors M′ 2 -M′ 3 inject the S′ 1 beam into the second amplification crystal (C 2 ). After a first pass through 2 nd amplification crystal (C 2 ) the amplified beam is labelled S′ 2 . In the embodiment of FIG. 6 , the amplified beam S′ 2 is reflected by mirrors M′ 4 -M′ 5 for passing again through the 1 st crystal (C 1 ) and forms amplified beam S′ 3 . Then, the amplified beam S′ 3 is injected using mirrors M′ 6 -M′ 7 into the second crystal (C 2 ) for another pass through the 2 nd crystal (C 2 ). Mirrors M′ 8 -M′ 9 inject amplified beam S′ 4 into the 1 st crystal for a 3 rd pass through this 1 st crystal (C 1 ). Mirrors M′ 10 -M′ 11 inject amplified beam S′ 5 into the 2 nd crystal (C 2 ) for a 3 rd pass, thus forming amplified beam S′ 6 . Mirrors M′ 12 -M′ 13 inject amplified beam S′ 6 into the 1 st crystal for a 4 th pass through this 1 st crystal (C 1 ). Mirrors M′ 14 -M′ 15 inject amplified beam S′ 7 into the 2 nd crystal (C 2 ) for a 4 th pass, thus forming amplified beam S′ 8 . Mirrors M′ 16 -M′ 17 inject amplified beam S′ 8 into the 1 st crystal for a 5 th pass through first crystal (C 1 ), thus forming amplified beam S′ 9 . Mirror M′ 18 extracts the amplified S′ 9 beam out of amplification system ( 100 ).
In summary, in the embodiment of FIG. 6 , the optical beam makes a total of N=9 interleaved passes through the amplification crystals, including five passes through crystal (C 1 ) and four passes through crystal (C 2 ).
In contrast to prior art multi-crystal amplification systems, the passes through the different crystals (C 1 , C 2 ) are interleaved. More precisely, the sequential passes are alternatively interleaved through the different crystals.
In the embodiment of FIG. 4 , after the 1 st pass through the 1 st crystal (C 1 ), following passes are double-passes alternatively though the 2 nd and 1 st crystal. Double passes through a crystal are performed in opposite directions along the crystal optical axis.
In the embodiment of FIG. 6 , after the 1 st pass through the 1 st crystal (C 1 ), following passes are single passes alternatively though the 2 nd and 1 st crystal. The beam passes through a crystal are all in the same direction.
According to various embodiments of the invention, each amplification crystal (C 1 , C 2 , . . . , C M ) can be temperature controlled. For example, the temperature of each crystal (C i ) i=1 . . . M can be controlled independently in order to control the gain of each amplification medium.
Different crystals (C 1 , C 2 , . . . , C M ) having different doping levels can also be used in order to control the gain of each amplification medium.
Another advantage of the system and method of the invention is that the use of multiple (minimum two) amplification crystals provides smoothing of to crystal defects.
The invention provides an improved system stability (large number of pump beams). The alternatively interleaved pass configuration allows to balance saturation among the two (or more) crystals. In the prior art serial configuration, most of the amplification process occurs during the first two passes through each crystal. In contrast, the interleaved pass configuration of the invention produces a significant amplification at each pass. In prior art multi-crystal configuration, the second crystal is exposed to very high infrared fluence, that can be destructive. The interleaved configuration is less stringent relatively to pumping and guarantees a higher long terme stability (laser pump drift is less critical).
The multipass amplification method according to the invention interleaves amplification between different amplification crystals. This method enables progressive saturation of the different amplification medium. The balanced saturation among the two amplification crystals provides long term stability of the system.
The system and method of the invention apply to a high power solid-state laser, and in particular to a Petawatt laser system.
In a preferred embodiment, the amplification system of the invention comprises two amplification crystals.
However, the amplification system can be scaled for higher amplification gain, using more than two amplification crystals, without increasing the amplification crystal size. The pump fluence remains also limited on all amplification crystals.
The invention applies to high power laser, and in particular lasers having either low repetition rate and high energy, or high repetition rate and low energy. | A high power solid-state non-regenerative optical amplification system ( 100 ) for amplifying a pulsed optical beam, includes a first optical amplification crystal (C 1 ) and a second optical amplification crystal (C 2 ) for amplifying the optical beam; optical pumping elements for longitudinal pumping amplification crystals (C 1 , C 2 ); reflective optical elements (M′ 1 , M′ 2 , . . . , M′ 17 ) suitable for reflecting the optical beam so that the optical beam makes a total number of N sequential passes through the amplification crystals (C 1 , C 2 ), wherein N is an integer and N>4. The reflective optical elements (M′ 1 , M′ 2 , . . . , M′ 17 ) are placed in a configuration suitable for alternatively interleaving the sequential optical beam passes through the 1 st crystal (C 1 ) and through the 2 nd crystal (C 2 ). A solid-state laser including the amplification system, and a method for amplifying a pulsed optical beam in a two-crystal multi-pass non-regenerative amplification system are also disclosed. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
Reference is made to commonly assigned copending patent applications: Ser. No. 08,057,250, filed May 3, 1993, entitled "AUTOMATIC TRAY PROCESSOR" in the names of John H. Rosenburgh, Joseph A. Manico, David L. Patton and Ralph L. Piccinino, Jr., and Ser. No. 08/056,458, filed May 3, 1993, entitled "MODULAR PROCESSING CHANNEL FOR AN AUTOMATIC TRAY PROCESSOR" in the names of Joseph A. Manico, Ralph L. Piccinino, Jr., David L. Patton and John H. Rosenburgh, and Ser. No. 08/057,131, filed May 3, 1993, entitled "VERTICAL AND HORIZONTAL POSITIONING AND COUPLING OF AUTOMATIC TRAY PROCESSOR CELLS" in the names of David L. Patton, Joseph A. Manico, John H. Rosenburgh and Ralph L. Piccinino, Jr., and Ser. No. 08/056,451, filed May 3, 1993, entitled "TEXTURED SURFACE WITH CANTED CHANNELS FOR AN AUTOMATIC TRAY PROCESSOR" in the names of Ralph L. Piccinino, Jr., John H. Rosenburgh, David L. Patton and Joseph A. Manico, and Ser. No. 08/056,730, filed May 3, 1993, entitled "AUTOMATIC REPLENISHMENT, CALIBRATION AND METERING SYSTEM FOR AN AUTOMATIC TRAY PROCESSOR" in the names of John H. Rosenburgh, Robert L. Horton and David L. Patton, and Ser. No. 08/056,457, filed May 3, 1993, entitled "CLOSED SOLUTION RECIRCULATION/SHUTOFF SYSTEM FOR AN AUTOMATIC TRAY PROCESSOR" in the names of John H. Rosenburgh, Joseph A. Manico, Ralph L. Piccinino, Jr. and David L. Patton, and Ser. No. 08/056,649, filed May 3, 1993, entitled "A SLOT IMPINGEMENT FOR AN AUTOMATIC TRAY PROCESSOR" filed herewith in the names of John H. Rosenburgh, David L. Patton, Joseph A. Manico and Ralph L. Piccinino, Jr., and Ser. No. 08/056,455, filed May 3, 1993, entitled "AUTOMATIC REPLENISHMENT, CALIBRATION AND METERING SYSTEM FOR A PHOTOGRAPHIC PROCESSING APPARATUS" in the names of John H. Rosenburgh, Robert L. Horton and David L. Patton.
1. Field of the Invention
The invention relates to the field of photography, and particularly to a photosensitive material processing apparatus.
2. Background of the Invention
The processing of photosensitive material involves a series of steps such as developing, bleaching, fixing, washing, and drying. With the development step being the most critical and sensitive to variations induced by time, temperature, agitation and chemical activity. These steps lend themselves to mechanization by conveying a continuous web of film or cut sheets of film or photographic paper sequentially through a series of stations or tanks, each one containing a different processing liquid appropriate to the process step at that station.
There are various sizes of photographic film processing apparatus, i.e., large photofinishing apparatus and microlabs. A large photofinishing apparatus utilizes tanks that contain approximately 100 liters of each processing solution. A small photofinishing apparatus or microlab utilizes tanks that may contain less than 10 liters of processing solution.
The chemicals contained in the processing solution: cost money to purchase; change in activity and are seasoned by the constituents of the photosensitive materials that leach out during the photographic process; and after the chemicals are used the chemicals must be disposed of in an environmentally safe manner. Thus, it is important in all sizes of photofinishing apparatus to reduce the volume of processing solution. The prior art suggest various types of replenishing systems that add or subtract specific chemicals to the processing solution to maintain a consistency of photographic characteristics in the material developed. It is possible to maintain reasonable consistency of photographic characteristics only for a certain period of replenishment. After a processing solution has been used a given number of times, the solution is discarded and a new processing solution is added to the tank.
Activity degradation due to instability of the chemistry, or chemical contamination, after the components of the processing solution are mixed together causes one to discard the processing solution in smaller volume tanks more frequently than larger volume tanks. Some of the steps in the photographic process utilize processing solutions that contain chemicals that are unstable, i.e., they have a short process life. Thus, processing solutions in tanks that contain unstable chemicals are discarded more frequently than processing solutions in tanks that contain stable chemicals.
PROBLEMS TO BE SOLVED BY THE INVENTION
The prior art used automatic photoprocessing equipment to process photosensitive material. Automatic photoprocessing equipment typically is configured as a sequential arrangement of transport racks submerged in tanks filled with volumes of processing solutions. The shape and configuration of the racks and tanks is inappropriate in certain environments, for instance: offices, homes, computer areas, etc.
The reason for the above is the potential damage to the equipment and the surroundings that may occur from spilled photographic processing solutions and the lack of facilities, i.e., running water and sinks to clean the racks and flush out the tanks. Photographic materials may become jammed in the processing equipment. In this situation the rack must be removed from the tank to gain access to the jammed photographic material in order to remove the jammed material. The shape and configuration of the racks and tanks made it difficult to remove a rack from a tank without spilling any processing solution.
The configuration of the rack and the tank is primarily due to the need to constantly provide active processing solution to the photosensitive material. One of the primary functions of a rack and tank processor is to provide the proper agitation of the processing solution. Proper agitation will send fresh processing solution to the surface or surfaces of the photosensitive material, while removing the exhausted processing solution from the photosensitive material.
The prior art suggests that if the volume of the various tanks contained within various sizes of photographic processing apparatus were reduced the same amount of film or photographic paper may be processed, while reducing the volume of processing solution that was used and subsequently discarded. One of the problems in using smaller volume tanks is to provide sufficient and consistent agitation of the processing solution to provide process uniformity across the photosensitive material.
The prior art also used alternative techniques to remove exhausted processing solution from the surface or surfaces of the photosensitive material and to provide fresh processing solution to the surface or surfaces of the photosensitive material. These techniques include rotating patterned drums, mesh screens, squeegee blades and solution jets, etc. Mesh screens and rotating drums work well in removing exhausted processing solution and supplying fresh processing solution. Mesh screens, squeegee blades and drums may damage the delicate surface or surfaces of the photosensitive material with debris that accumulates within the mesh, on the blade, or on the drum surface. An additional problem with the rotating drum is that the rotating drum is large and thus limits the minimum size of the processing equipment. A further problem with a rotating drum is that it can only process one sheet of photosensitive material at a time.
The problem of nonuniform processing of the photosensitive material is exacerbated when the widely spaced non-arrayed solution jets are used in close proximity to the photosensitive material. Solution jets also provide a method for removing and supplying fresh processing solution to and from the surface or surfaces of the photosensitive material.
However, if one used solution jets in the form of widely spaced non-arrayed jets or holes to distribute fresh processing solution in small volume processing tanks, the photosensitive material would not be uniformly developed. The reason for the above is that when the fresh processing solution was distributed, the fresh processing solution was close to the photosensitive material and did not have space to uniformly spread out across the surfaces of the photosensitive material. If the distance between the widely arrayed jets or holes and the surface of the photosensitive material were increased to obtain adequate distribution of the fresh processing solution, one would no longer have a small volume tank.
Slots were not used by the prior art to distribute fresh processing solution in large volume tanks since the processing solution would not travel uniformly across a large volume of solution.
As the photosensitive material passes through the tank, a boundary layer is formed between the surfaces of the photosensitive material and the processing solution. The processing solution moves with the photosensitive material. Thus, the boundary layer between the photosensitive material and the processing solution has to be broken up to enable fresh processing solution to reach the photosensitive material. Rollers were used in large prior art tanks to break up the boundary layer. The roller squeegeed the exhausted processing solution away from the surfaces of the photosensitive material, thus, permitting fresh processing solution to reach the surfaces of the photosensitive material. One would not use only closely spaced rollers in small volume tanks, to break the boundary layer between the photosensitive material and the processing solution, since rollers require additional space and add to the volume of required processing solution.
A further problem with existing processors is that the processor may only process, at a given time, photosensitive material in a roll or cut sheet format. In addition, processors that are configured to process photosensitive material in a cut sheet format, may be limited in their ability to process the photosensitive material, by the minimum or maximum length of the photosensitive material, that may be transported.
Additional rollers are required to transport shorter photosensitive material lengths. The reason for this is that, a portion of the photosensitive material must always be in physical contact with a pair of transporting rollers, or the cut sheet of photosensitive material will fail to move through the entire processor. As the number of required transport rollers increases, the agitation of the processing solution decreases. Even though the rollers remove processing solution and hence, break up the boundary layer, the additional rollers severely impede the flow of fresh processing solution to and exhausted processing solution from the surface of the photosensitive material.
Certain photosensitive materials and processing solutions are more uniformily sensitive to variations in the fluid dynamics of processing solution impingement on the photosensitive material. For example when the photosensitive material is developed the photosensitive material may have nonuniform density.
SUMMARY OF THE INVENTION
This invention overcomes the disadvantages of the prior art by providing a low volume photographic material processing apparatus that introduces fresh processing solution uniformly across the surfaces of a photosensitive material. The processing apparatus utilizes a slot nozzle configuration, whose fluid distribution pattern meets or exceeds the width of the photosensitive material. The slot nozzle does not have to be periodically changed or cleaned and is designed in such a manner that an amount of fresh processing solution exits the slot nozzle at a sufficient velocity to disrupt the boundary layer of exhausted processing solution allowing fresh processing solution to reach the surfaces of the photosensitive material. The slot nozzle permits the velocity of the exiting processing solution to be varied by changing the pressure of the solution. Thus, the amount of fresh processing solution reaching the surfaces of the photosensitive material may be controlled. Hence, the chemical reaction between the photosensitive material and the fresh processing solution reaching the surface of the photosensitive material may be controlled.
Additional slot nozzles may be utilized to control the amount of chemical reaction between the fresh processing solution and the photosensitive material. When uniformily sensitive, photosensitive materials and processing solutions are used a series of slot nozzles that have alternating flow patterns may be used to provide for uniform development. The alternating flow patterns are created by introducing processing solution into opposite ends of alternating slot nozzles.
ADVANTAGEOUS EFFECT OF THE INVENTION
The above arrangements of solution impingement slot nozzles provide fresh processing solution to the photosensitive material while removing exhausted processing solution from the photosensitive material. The act of alternating the flow patterns of processing solution by introducing processing solution into opposite ends of alternating slot nozzles, having corresponding tapered delivery channels, compensates for nonuniform processing solution delivery inadvertently introduced during single direction flow. The foregoing may arise as solution filters become clogged during use reducing processing solution flow, or processing solution viscosity changes, or percipation of the processing solution that creates restrictions to flow, or variations introduced by tolerances in the manufacture of the slot nozzle.
The foregoing is accomplished by providing an apparatus for processing photosensitive materials, which comprises: a container which contains a channel through which a processing solution flows, the entrance and exit of the channel are upturned to contain processing solution within the channel; means coupled to the channel for transporting the photosensitive material from the channel entrance, through the channel, to the channel exit, the channel and the means are relatively dimensioned so that a small volume for holding processing solution and photosensitive material is formed between the channel and the means; means for circulating the processing solution through the small volume and the container; at least a first and a second slot nozzle coupled to the circulating means and forming a portion of the channel for controlling the velocity and amount of processing solution that dynamically impinges on the surface of the photosensitive material; a first conduit that is connected to one end of the first slot nozzle and the circulating means so that processing solution may travel in the first slot nozzle in a first direction; and a second conduit that is connected to the other end of the second slot nozzle and the circulation means so that processing solution may travel in the second slot nozzle in a second direction.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective drawing of module 10;
FIG. 2 is a partially cut away drawing of module 10 in which material 21 has an emulsion on one surface and nozzles 17a, 17b and 17c are on the bottom portion of container 11 facing the emulsion surface of material 21;
FIG. 3 is a partially cut away drawing of an alternate embodiment of module 10 of FIG. 2 in which material 21 has an emulsion on one surface and nozzles 17d, 17e and 17f are on the top portion of container 11 facing the emulsion surface of material 21;
FIG. 4 is a partially cut away drawing of an alternate embodiment of module 10 of FIG. 2 in which material 21 has an emulsion on both surfaces and nozzles 17g, 17h and 17i are on the top portion of container 11 facing one emulsion surface of material 21 and nozzles 17j, 17k, and 17l are on the bottom portion of container 11 facing the other emulsion surface of material 21;
FIG. 5 is a schematic drawing of the processing solution recirculation system of the apparatus of this invention;
FIG. 6 is a perspective drawing of a plurality of slot nozzle illustrating counter cross flow; and
FIG. 7 is a perspective drawing of an alternate embodiment of a slot nozzle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings in detail, and more particularly to FIG. 1, the reference character 10 represents a processing module, which may stand alone or be easily combined or adjoined with other processing modules 10 to form a continuous low volume unit for processing photosensitive materials.
Processing module 10 includes: a container 11; an upturned entrance channel 100 (described in the description of FIG. 2); an entry transport roller assembly 12; transport roller assemblies 13; an exit transport roller assembly 15; an upturned exit channel 101 (described in the description of FIG. 2); high impingement slot nozzles 17a, 17b and 17c; a drive 16 and a rotating assembly 18, assembly 18 may be any known means for turning drive 16, i.e., a motor, a gear, a belt, a chain, etc. An access hole 61 is provided in container 11. Hole 61 is utilized for the interconnection of modules 10. Assemblies 12, 13 and 15 are positioned within container 11 in the vicinity of the walls of container 11 and slot nozzles 17a, 17b and 17c are positioned within the vicinity of the walls of container 11. Drive 16 is connected to roller assemblies 12, 13 and 15 and turning assembly 18 and assembly 16 is used to transmit the motion of assembly 18 to assemblies 12, 13 and 15.
Roller assemblies 12, 13, and 15, and slot nozzles 17a, 17b and 17c may be easily inserted into or removed from container 11. Roller assembly 13 includes: a top roller 22; a bottom roller 23; tension springs 62, which holds top roller 22 in compression with respect to bottom roller 23; a bearing bracket 26; and a channel section 24. A narrow channel opening 25 exists within section 24. Opening 25 on the entrance side of section 24 may be the same size and shape as opening 25 on the exit side of section 24. Opening 25 on the entrance side of section 24 may also be relieved, tapered or larger than the exit side of section 24 to accommodate rigidity variations of various types of photosensitive material 21. Channel opening 25 forms a portion of processing channel 25. Rollers 22 and 23 may be drive or driven rollers and rollers 22 and 23 are connected to bracket 26. Rollers 22 and 23 are rotated by intermeshing gears 28.
Photosensitive material 21 is transported in either direction A or direction B automatically through processing channel 25 by roller assemblies 12, 13 and 15. Photosensitive material 21 may be in a cut sheet or roll format or photosensitive material 21 may be simultaneously in a roll and simultaneously in a cut sheet format. Photosensitive material 21 may contain an emulsion on either or both of its surfaces.
When cover 20 is placed on container 11 a light tight enclosure is formed. Thus, module 10 with its associated recirculation system 60, which is described in the description of FIG. 5, will be a stand alone light tight module that is capable of processing photosensitive material, i.e., a monobath. When two or more modules 10 are combined a multi-stage continuous processing unit may be formed. The combination of one or more modules 10 will be more fully set forth in the description of FIG. 6.
FIG. 2 is a partially cut away section of module 10 of FIG. 1. Assemblies 12, 13 and 15, nozzles 17a, 17b and 17c and backing plate 9 are designed in a manner to minimize the amount of processing solution that is contained in processing channel 25, vessel 11, recirculation system 60 (FIG. 5) and gaps 49a, 49b, 49c and 49d. At the entrance of module 10, an upturned channel 100 forms the entrance to processing channel 25. At the exit of module 10, an upturned channel 101 forms the exit to processing channel 25. Assembly 12 is similar to assembly 13. Assembly 12 includes: a top roller 30; a bottom roller 31; tension springs 62 (not shown) which holds top roller 30 to bottom roller 31; a bearing bracket 26; and a channel section 24. A portion of narrow processing channel 25 is formed by channel section 24. Rollers 30 and 31 may be drive or driven rollers and rollers 30 and 31 are connected to bracket 26. Assembly 15 is similar to assembly 13, except that assembly 15 has an additional two rollers 130 and 131, which operate in the same manner as rollers 32 and 33. Assembly 15 includes: a top roller 32; a bottom roller 33; tension springs 62 (not shown); a top roller 130; a bottom roller 131; a bearing bracket 26; a channel section 24. A portion of narrow processing channel 25 exists within section 24. Channel section 24 forms a portion of processing channel 25. Rollers 32, 33, 130 and 131 may be drive or driven rollers and rollers 32, 33, 130 and 131 are connected to bracket 26.
Backing plate 9 and slot nozzles 17a, 17b and 17c are affixed to container 11. The embodiment shown in FIG. 2 will be used when photosensitive material 21 has an emulsion on one of its surfaces. The emulsion side of material 21 will face slot nozzles 17a, 17b and 17c. Material 21 enters channel 25 between rollers 30 and 31 and moves past backing plate 9 and nozzle 17a. Then material 21 moves between rollers 22 and 23 and moves past backing plates 9 and nozzles 17b and 17c. At this point material 21 will move between rollers 32 and 33, and move between rollers 130 and 131 and exit processing channel 25.
Conduit 48a connects gap 49a, via port 44a to recirculation system 60 via port 44 (FIG. 5), which is more fully described in the description of FIG. 5, and conduit 48b connects gap 49b, via port 45a to recirculation system 60 via port 45 (FIG. 5). Conduit 48c connects gap 49c, via port 46a to recirculation system 60 via port 46 (FIG. 5) and conduit 48d connects gap 49d, via port 47a to recirculation system 60 via port 47 (FIG. 5). Slot nozzle 17a is connected to recirculation system 60 via conduit 50a and inlet port 41a via port 44 (FIG. 5) and slot nozzle 17b is connected to recirculation system 60 via conduit 50b and inlet port 42a via inlet port 42 (FIG. 5). Conduit 50c connects nozzle 17c, via inlet port 43a to recirculation system 60 via port 43 (FIG. 5). Sensor 52 is connected to container 11 and sensor 52 is used to maintain a processing solution level 235 relative to conduit 51. Excess processing solution may be removed by overflow conduit 51.
Textured surface 200 or 205 is affixed to the surface of backing plate 9 that faces processing channel 25 and to the surface of slot nozzles 17a, 17b and 17c that faces processing channel 25.
FIG. 3 is a partially cut away drawing of an alternate embodiment of module 10 of FIG. 2 in which material 21 has an emulsion on one surface and nozzles 17d, 17e and 17f are on the top portion of container 11. Assemblies 12, 13 and 15, nozzles 17d, 17e and 17f and backing plate 9 are designed in a manner to minimize the amount of processing solution that is contained in processing channel 25 and gaps 49e, 49f, 49g and 49h. At the entrance of module 10, an upturned channel 100 forms the entrance to processing channel 25. At the exit of module 10, an upturned channel 101 forms the exit to processing channel 25. Assembly 12 is similar to assembly 13. Assembly 12 includes: a top roller 30; a bottom roller 31; tension springs 62 (not shown) which holds top roller 30 in compression with respect to bottom roller 31, a bearing bracket 26; and a channel section 24. A portion of narrow channel opening 25 exists within section 24. Channel section 24 forms a portion of processing channel 25. Rollers 30 and 31 may be drive or driven rollers and rollers 30 and 31 are connected to bracket 26. Assembly 15 is similar to assembly 13, except that assembly 15 has an additional two rollers 130 and 131 that operate in the same manner as rollers 32 and 33. Assembly 15 includes: a top roller 32; a bottom roller 33; a tension spring 62 (not shown); a top roller 130; a bottom roller 131; a bearing bracket 26; and a channel section 24. A portion of narrow processing channel 25 exists within section 24. Channel section 24 forms a portion of processing channel 25. Rollers 32, 33, 130 and 131 may be drive or driven rollers and rollers 32, 33, 130 and 131 are connected to bracket 26.
Backing plate 9 and slot nozzles 17d, 17e and 17f are affixed to container 11. The embodiment shown in FIG. 3 will be used when photosensitive material 21 has an emulsion on one of its surfaces. The emulsion side of material 21 will face slot nozzles 17d, 17e and 17f. Material 21 enters channel 25 between rollers 30 and 31 and moves past backing plate 9 and nozzle 17d. Then material 21 moves between rollers 22 and 23 and moves past backing plates 9 and nozzles 17e and 17f. At this point material 21 will move between rollers 32 and 33 and move between rollers 130 and 131 and exit processing channel 25.
Conduit 48e connects gap 49e, via port 44b to recirculation system 60 via port 44 (FIG. 5) and conduit 48f connects gap 49f, via port 45b to recirculation system 60 via port 45 (FIG. 5). Conduit 48g connects gap 49g, via port 46b to recirculation system 60 via port 46 (FIG. 5) and conduit 48h connects gap 49h, via port 47b to recirculation system 60 via port 47 (FIG. 5). Slot nozzle 17d is connected to recirculation system 60 via conduit 50d and inlet port 41b via inlet 41 (FIG. 5) and slot nozzle 17e is connected to recirculation system 60 via conduit 50e and inlet port 42b via port 42 (FIG. 5). Conduit 50f connects nozzle 17f, via inlet port 43b to recirculation system 60 via port 43 (FIG. 5). Sensor 52 is connected to container 11 and sensor 52 is used to maintain a processing solution level 235 relative to conduit 51. Excess processing solution may be removed by overflow conduit 51.
Textured surface 200 or 205 is affixed to the surface of backing plate 9 that faces processing channel 25 and to the surface of slot nozzles 17d, 17e and 17f that faces processing channel 25.
FIG. 4 is a partially cut away drawing of an alternate embodiment of module 10 of FIG. 2 in which material 21 has an emulsion on both surfaces and nozzles 17g, 17h and 17i are on the top portion of container 11 facing one emulsion surface of material 21 and nozzles 17j, 17k, and 17L are on the bottom portion of container 11 facing the other emulsion surface of material 21. Assemblies 12, 13 and 15, nozzles 17g, 17h, 17i, 17j, 17k and 17L are designed in a manner to minimize the amount of processing solution that is contained in processing channel 25 and gaps 49i, 49j, 49k and 49L. At the entrance of module 10, an upturned channel 100 forms the entrance to processing channel 25. At the exit of module 10, an upturned channel 101 forms the exit to processing channel 25. Assembly 12 includes: a top roller 30; a bottom roller 31; tension springs 62 (not shown) which holds top roller 30 in compression with respect to bottom roller 31, a bearing bracket 26; and a channel section 24. A portion of narrow processing channel 25 exists within section 24. Channel section 24 forms a portion of processing channel 25. Rollers 30, 31, 130 and 131 may be drive or driven rollers and rollers 30, 31, 130 and 131 are connected to bracket 26. Assembly 15 is similar to assembly 13, except that assembly 15 has an additional two rollers 130 and 131 that operate in the same manner as rollers 32 and 33. Assembly 15 includes: a top roller 32; a bottom roller 33; tension springs 62 (not shown); a top roller 130; a bottom roller 131; a bearing bracket 26; and a channel section 24. A portion of narrow processing channel 25 exits within section 24. Channel section 24 forms a portion of processing channel 25. Rollers 32, 33, 130 and 131 may be drive or driven rollers and rollers 32, 33, 130 and 131 are connected to bracket 26.
Slot nozzles 17g, 17h and 17i are affixed to the upper portion of container 11. Slot nozzles 17j, 17k and 17L are affixed to the lower portion of container 11. The embodiment shown in FIG. 4 will be used when photosensitive material 21 has an emulsion on both of its two surfaces. One emulsion side of material 21 will face slot nozzles 17g, 17h and 17i and the other emulsion side of material 21 will face slot nozzles 17j, 17k and 17L. Material 21 enters channel 25 between rollers 30 and 31 and moves past an nozzles 17g and 17j. Then material 21 moves between rollers 22 and 23 and moves past nozzles 17h, 17k, 17i and 17L. At this point material 21 will move between rollers 32 and 33 and move between rollers 130 and 131 and exit processing channel 25.
Conduit 48i connects gap 49i, via port 44c to recirculation system 60 via port 44 (FIG. 5) and conduit 48j connects gap 49k, via port 45c to recirculation system 60 via port 45 (FIG. 5). Conduit 48k connects gap 49L, via port 46c to recirculation system 60 and conduit 48L connects gap 49j, via port 47c to recirculation system 60 via port 47 (FIG. 5). Slot nozzle 17g is connected to recirculation system 60 via conduit 50g via port 41 (FIG. 5). Slot nozzle 17h is connected to recirculation system 60 via conduit 50h and inlet port 62 via port 42 (FIG. 5). Conduit 50i connects nozzle 17i, via inlet port 63 to recirculation system 60 via port 43 (FIG. 5). Slot nozzle 17j is connected to recirculation system 60 via conduit 50j and inlet port 41c via port 41 (FIG. 5) and slot nozzle 17k is connected to recirculation system 60 via conduit 50k and inlet port 42c via port 42 (FIG. 5). Slot nozzle 17L is connected to recirculation system 60 via conduit 50L and inlet port 43c via port 43 (FIG. 5). Sensor 52 is connected to container 11 and sensor 52 is used to maintain a level of processing solution relative to conduit 51. Excess processing solution may be removed by overflow conduit 51. Material 21 enters upturned channel entrance 100, then passes through channel section 24 of channel 25 between rollers 30 and 31 and moves past nozzles 17g and 17j. Then material 21 moves between rollers 22 and 23 and moves past nozzles 17h and 17k, 17L and 17i. At this point material 21 will move between rollers 32 and 33 and exit processing channel 25.
Conduit 48i connects gap 49i, via port 44c to recirculation system 60 via port 44 (FIG. 5) and conduit 48j connects gap 49k, via port 45c to recirculation system 60 via port 45 (FIG. 5). Conduit 48k connects gap 49L, via port 46c to recirculation system 60 via port 46 (FIG. 5) and conduit 48L connects gap 49j, via port 47c to recirculation system 60 via port 47 (FIG. 5). Sensor 52 is connected to container 11 and sensor 52 is used to maintain a processing solution level 235 relative to conduit 51. Excess processing solution may be removed by overflow conduit 51.
Textured surface 200 or 205 is affixed to the surface of slot nozzles 17g, 17h, 17i, 17j, 17k and 17L that face processing channel 25.
FIG. 5 is a schematic drawing of processing solution recirculation system 60 of the apparatus of this invention. Module 10 is designed in a manner to minimize the volume of channel 25. The outlets 44, 45, 46 and 47 of module 10 are connected to recirculating pump 80 via conduit 85. Recirculating pump 80 is connected to manifold 64 via conduit 63 and manifold 64 is coupled to filter 65 via conduit 66. Filter 65 is connected to heat exchanger 86 and heat exchanger 86 is connected to channel 25 via conduit 4. Heat exchanger 86 is also connected to control logic 67 via wire 68. Control logic 67 is connected to heat exchanger 86 via wire 70 and sensor 52 is connected to control logic 67 via wire 71. Metering pumps 72, 73 and 74 are respectively connected to manifold 64 via conduits 75, 76 and 77.
The photographic processing chemicals that comprise the photographic solution are placed in metering pumps 72, 73 and 74. Pumps 72, 73 and 74 are used to place the correct amount of chemicals in manifold 64, when photosensitive material sensor 210 senses that material 21 (FIG. 1) is entering channel 25, sensor 210 transmits a signal to pumps 72, 73 and 74 via line 211 and control logic 67. Manifold 64 introduces the photographic processing solution into conduit 66.
The photographic processing solution flows into filter 65 via conduit 66. Filter 65 removes contaminants and debris that may be contained in the photographic processing solution. After the photographic processing solution has been filtered, the solution enters heat exchanger 86.
Sensor 52 senses the solution level and sensor 8 senses the temperature of the solution and respectively transmits the solution level and temperature of the solution to control logic 67 via wires 71 and 7. For example, control logic 67 is the series CN 310 solid state temperature controller manufactured by Omega Engineering, Inc. of 1Omega Drive, Stamford, Conn. 06907. Logic 67 compares the solution temperature sensed by sensor 8 and the temperature that exchanger 86 transmitted to logic 67 via wire 70. Logic 67 will inform exchanger 86 to add or remove heat from the solution. Thus, logic 67 and heat exchanger 86 modify the temperature of the solution and maintain the solution temperature at the desired level.
Sensor 52 senses the solution level in channel 25 and transmits the sensed solution level to control logic 67 via wire 71. Logic 67 compares the solution level sensed by sensor 52 via wire 71 to the solution level set in logic 67. Logic 67 will inform pumps 72, 73 and 74 via wire 83 to add additional solution if the solution level is low. Once the solution level is at the desired set point control logic 67 will inform pumps 72, 73 and 74 to stop adding additional solution.
Any excess solution may either be pumped out of module 10 or removed through level drain overflow 84 via conduit 81 into container 82.
At this point the solution enters module 10 via inlets 41, 42 and 43. When module 10 contains too much solution the excess solution will be removed by overflow conduit 51, drain overflow 84 and conduit 81 and flow into reservoir 82. The solution level of reservoir 82 is monitored by sensor 212. Sensor 212 is connected to control logic 67 via line 213. When sensor 212 senses the presence of solution in reservoir 82, a signal is transmitted to logic 67 via line 213 and logic 67 enables pump 214. Thereupon pump 214 pumps solution into manifold 64. When sensor 212 does not sense the presence of solution, pump 214 is disabled by the signal transmitted via line 213 and logic 67. When solution in reservoir 82 reaches overflow 215, the solution will be transmitted through conduit 216 into reservoir 217. The remaining solution will circulate through channel 25 and reach outlet lines 44, 45, 46 and 47. Thereupon, the solution will pass from outlet lines 44, 45, 46 and 47 to conduit line 85 to recirculation pump 80. The photographic solution contained in the apparatus of this invention, when exposed to the photosensitive material, will reach a seasoned state more rapidly than prior art systems, because the volume of the photographic processing solution is less.
FIG. 6 is a perspective drawing of a plurality of slot nozzles 17. Slot 160 runs across surface 161 of slot nozzle 17. Conduit 162 connects slot 161 to inlets 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63. Flange 108 of nozzle 17 is attached to container 11 by any known conventional means that will prevent the leaking of processing solution from container 11, e.g., gaskets, screws etc. Processing solution will enter inlet 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63 proceed down narrowing conduit 162 with an ever increasing velocity providing a uniform flow of processing solution out of the entire length of slot 160. The width X of the processing solution exiting slot 160 is adequate to cover the width of the photosensitive material 21. The depth or thickness y of slot 160 is such that y/x (100) is less than 1.
Slot 163 runs across surface 164 of slot nozzle 17. Conduit 165 connects slot 163 to inlets 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63. Flange 108 of nozzle 17 is attached to container 11 by any known conventional means that will prevent the leaking of processing solution from container 11, e.g., gaskets, screws, etc. Processing solution will enter inlet 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63 proceed down narrowing conduit 165 with an ever increasing velocity providing a uniform flow of processing solution out of the entire length of slot 163. The width X of the processing solution exiting slot 163 is adequate to cover the width of the photosensitive material 21. The depth or thickness y of slot 163 is such that y/x (100) is less than 1.
Slot 166 runs across surface 167 of slot nozzle 17. Conduit 168 connects slot 166 to inlets 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63. Flange 108 of nozzle 17 is attached to container 11 by any known conventional means that will prevent the leaking of processing solution from container 11, e.g., gaskets, screws, etc. Processing solution will enter inlet 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63 proceed down narrowing conduit 168 with an ever increasing velocity providing a uniform flow of processing solution out of the entire length of slot 166. The width X of the processing solution exiting slot 166 is adequate to cover the width of the photosensitive material 21. The depth or thickness y of slot 166 is such that y/x (100) is less than 1.
Slot 169 runs across surface 170 of slot nozzle 17. Conduit 165 connects slot 163 to inlets 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63. Flange 108 of nozzle 17 is attached to container 11 by any known conventional means that will prevent the leaking of processing solution from container 11, e.g., gaskets, screws, etc. Processing solution will enter inlet 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63 proceed down narrowing conduit 171 with an ever increasing velocity providing a uniform flow of processing solution out of the entire length of slot 169. The width X of the processing solution exiting slot 169 is adequate to cover the width of the photosensitive material 21. The depth or thickness y of slot 169 is such that y/x (100) is less than 1.
Thus, processing solution exiting slots 160, 163, 166 and 169 of slot nozzles 17 will alternate in direction. Four slot nozzles 17 have been described above, it will be obvious to one skilled in the art that any even number of nozzles 17 may be utilized and that slots 160, 163, 166 and 169 may have different shapes.
FIG. 7 is a perspective drawing of an alternate embodiment of slot nozzle 17. Slots 120 and 121 run across surface 122 of slot nozzle 17. The orientation of slots 120 and 121 is determined by angles Z and Z'. Angles Z and Z' are between 0 and 89 degrees. Narrowing conduit 124 is connected to slot 120 and conduit 124 is connected to manifold 125. Manifold 125 is connected to inlets 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63. Conduit 127 connects manifold 125 to narrowing conduit 126. Flange 108 of nozzle 17 is attached to container 11 by any known conventional means that will prevent the leaking of processing solution from container 11, e.g., gaskets, screws, etc. Processing solution will enter inlet 41a, 41b, 41c, 42a, 42b, 42c, 43a, 43b, 43c, 61, 62 and 63 proceed through manifold 125, and simultaneously proceed through narrowing conduit 124 and conduit 127. The processing solution travelling in conduit 124 will have an ever increasing velocity as the processing solution proceeds down conduit 124. This will provide a uniform flow of processing solution out of the entire length of slot 120. The processing solution travelling in conduit 127 will proceed through conduit 126 and have an ever increasing velocity as the processing solution proceeds down conduit 126. This will provide a uniform flow of processing solution out of the entire length of slot 121. Width X of slots 120 and 121 will be wider than the width of photosensitive material 21. The depth or thickness y of slots 120 and 121 is such that y/x (100) is less than 1.
The above specification describes a new and improved apparatus for processing photosensitive materials. It is realized that the above description may indicate to those skilled in the art additional ways in which the principles of this invention may be used without departing from the spirit. It is, therefore, intended that this invention be limited only by the scope of the appended claims.
______________________________________Parts List:______________________________________4 conduit7 wire8 sensor9 backing plate10 processing module11 container12 transport roller assembly13 transport roller assembly15 transport roller assembly16 drive17 nozzle17a-l nozzles18 rotating assembly20 cover21 photosensitive material22 roller23 roller24 channel section25 channel26 bearing bracket28 intermeshing gears30 roller31 roller32 roller33 roller41 port41a-c inlet port42 port42a-c inlet port43 port43a-c inlet port44 port44a-c port45 port45a-c port46 port46a-c port47 port47a-c port48a-l conduit49a-l gap50a-l conduit51 overflow conduit52 sensor60 recirculation system61 access hole62 tension springs63 conduit64 manifold65 filter66 conduit67 control logic68 wire70 wire71 wire72 metering pump73 metering pump74 metering pump75 conduit76 conduit77 conduit80 recirculating pump81 conduit82 container83 wire84 drain overflow85 conduit86 heat exchanger100 entrance channel101 exit channel108 flange120 slot121 slot122 surface124 conduit125 manifold126 conduit127 conduit130 roller131 roller160 slot161 surface162 conduit163 slot164 surface165 conduit166 slot167 surface168 conduit169 slot170 surface171 conduit200 textured surface205 textured surface210 sensor211 line212 sensor213 line214 pump215 overflow216 conduit217 reservoir235 solution level______________________________________ | A low volume photographic material processing apparatus that utilizes a narrow horizontal processing channel with an upturned entrance and exit to contain processing solution within the channel. The channel is formed by a repeating combination of squeegee pinch rollers and impingement slot nozzles. Photographic processing solution is introduced into opposite ends of alternating impingement slot nozzles, having delivery channels and the squeegee pinch rollers are used to remove the processing solution from the photosensitive material and provide transport of the photosensitive material. Solution level control is achieved by drains positioned below the tops of the upturned sections. The slot nozzles and the pinch rollers work interactively to break down the chemical barrier layer. | 6 |
BACKGROUND OF THE INVENTION
[0001] An image-reading device installed in a copy machine or a similar machine generally is made so that a carriage with a mirror is moved along an original document placed on a platen glass, image light of the original document is reflected by the mirror, and the reflected image light is guided to a light receiving device such as a CCD via a rod lens array (an arrangement of multiple gradient index lenses, known as SELFOC lenses), as disclosed in Japanese Laid-Open Patent Application H10-257251.
[0002] In addition, the image-reading device may be constructed so as to enable reading an image by moving an original document. With this type of image-reading device, a feeder for feeding the original to a position at one end of the platen glass is provided, the image is read while moving the original document, and the carriage is stopped at an end position. With this type of image-reading device, it is desirable that the platen glass be separated from the feeder in order to be isolated from vibrations associated with feeding the original document. Therefore, a separate end glass, known as a CVT glass in order to distinguish it from the platen glass, is used at the bottom of the feeder.
[0003] Additionally, the applicant of the present application has developed an image-reading device that does not require a mirror by providing a rod lens array (formed of SELFOC lenses) and a CCD on the carriage as an alternative to the mirror scan method described above. With this image-reading device, the optical axis of the rod lens array faces the vertical direction toward the platen glass, and the light that passes through the rod lens array directly forms an image at the CCD light receiving device.
[0004] However, since the focal depth of the rod lens array is narrower (0.5 mm or less being common) than lenses normally used in lens barrels, the distance between the rod lens array and the platen glass must be established very strictly in an image-reading device using a rod lens array as described above. In order to maintain a fixed distance between the original document and the carriage in this type of image-reading device, sliding members that protrude in the vertical direction are installed on the carriage, and the carriage, including these sliding members, is biased elastically upward so that the sliding members make contact with the bottom surface of the platen glass.
[0005] However, with the image-reading device described above, when the carriage moves between the platen glass and the CVT glass, resistance occurs as the sliding member passes across the gap between the two glasses. Due to this, there is the risk of the sliding member wearing rapidly and vibration occurring that results in the carriage not being at its appropriate height and the movement of the carriage not being properly synchronized with a driving motor, such as a stepping motor.
BRIEF SUMMARY OF THE INVENTION
[0006] The present invention relates to an image-reading device that includes a sliding member on the carriage that passes smoothly between the platen glass and the CVT glass, preventing, for example, problems of wear of the sliding member and loss of synchronism of a stepping motor that drives the carriage. The present invention further relates to an image-reading device that acquires image data by scanning an original by moving an optical unit mounted on a carriage relative to an original and especially relates to an image-reading device that includes a feed mechanism, particularly an auto-feed mechanism, for an original document.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present invention will become more fully understood from the detailed description given below and the accompanying drawings, which are given by way of illustration only and thus are not limitative of the present invention, wherein:
[0008] [0008]FIG. 1 shows a side cross-sectional view of a portion of an image-reading device of the present invention;
[0009] [0009]FIGS. 2A-2B show diagrams of carriage velocities versus time for a conventional image-reading device and for the image-reading device of FIG. 1, respectively; and
[0010] [0010]FIG. 3 shows a perspective view of the entire image-reading device of FIG. 1.
DETAILED DESCRIPTION
[0011] A preferred embodiment of the image-reading device of the present invention will now be described with reference to FIGS. 1-3.
[0012] [0012]FIG. 1 shows a side cross-sectional view of an image-reading device of the present invention and FIG. 3 shows a perspective view of the entire image-reading device of FIG. 1. The image-reading device may form part of a copy machine, a facsimile machine, or a similar machine. As shown in FIGS. 1 and 3, a housing 1 forms the external frame of the image-reading device. The housing 1 has a rectangular box shape with an open top that is covered by a platen glass 10 . A CVT glass, that is, an end glass 11 is installed adjacent to the platen glass 10 , and a sheet member 12 , which may be MYLAR tape, covers the gap 12 a between the platen glass 10 and CVT glass 11 , and is adhered to the lower surfaces of the CVT glass 11 and the platen glass 10 . Other easily available materials, such as a stainless steel sheet material or a resin sheet material, that do not require reinforcing or strengthening may be use as the material of the sheet member.
[0013] As shown in FIG. 1, a cover 2 that may be freely opened or closed, varying its separation from the platen glass 10 and the CVT glass 11 , is arranged above the platen glass 10 and the CVT glass 11 . Also shown in FIG. 1 are a paper tray 20 that receives an original document and a document feeder 22 that automatically feeds the original document from the paper tray 20 one page at a time across the upper surface of the CVT glass 11 with the assistance of an ejection port 21 .
[0014] As shown in FIG. 3, on the bottom surface of the housing 1 , a pair of rails 13 , 13 that extend horizontally are installed parallel to each other. A carriage 3 is supported with the ability to slide freely in the lengthwise direction on the rails 13 , 13 . On the carriage 3 , three sliding members (i.e., projections) 30 , 31 , 31 , are mounted to project upwardly from the carriage 3 . The carriage 3 is pressed upwardly elastically by a spring or a similar biasing structure so that the sliding members 30 , 31 , 31 , are pressed against the bottom surfaces of the platen glass 10 and the CVT glass 11 . In this way, the carriage is securely supported in three locations, enabling the sliding member to securely slide against the platen glass and the end glass. The sliding members 30 , 31 , 31 may be made of plastic (i.e., synthetic resin) that has a small coefficient of friction. The upper ends of the sliding members are nearly spherical in order to decrease the frictional resistance with the platen glass 10 or any other surfaces they contact.
[0015] A rod lens array (SELFOC lenses) 32 with the optical axis of the lens array being vertical is mounted on the upper surface of the carriage 3 . A CCD 33 , which is a photoelectric transfer device and includes light detecting elements, receives light focused by the rod lens array and is arranged below the rod lens array 32 . Additionally, as shown in FIG. 1, a light source 34 that irradiates light diagonally in the upward direction is mounted on the carriage 3 . Furthermore, a slider 35 that slides along each rail 13 is mounted on the lower surface of the carriage 3 . The slider 35 is mounted via a compression spring 35 a between the frame of the carriage 3 and the rail, biasing the carriage 3 toward the platen glass 10 and other structures. The carriage 3 constructed in this manner travels on the rails 13 , 13 by a driving mechanism 4 , described below.
[0016] Both ends of a wire 40 are connected to the carriage 3 , and the wire 40 is linked to both ends of the carriage 3 by stretching the wire 40 between both ends of the carriage 3 within the housing 1 through pulleys (not shown in the drawings) arranged in the four corners of the housing 1 . Additionally, as shown in FIG. 1, the wire 40 is wrapped a plurality of times around a driving pulley 41 mounted on the axis of rotation of a motor 42 , such as a stepping motor.
[0017] As shown in FIG. 1, the image-reading device includes a controller 5 for driving the carriage. The controller 5 controls the rotation of the rotor of the motor 42 according to programmed control, which, in turn, controls the position and speed of the carriage 3 . The controller 5 may also include electronic circuits for receiving image data from the CCD 33 and transferring the image data to an image processor.
[0018] The operation of the image-reading device is as follows, with further reference to FIGS. 1-3. The original position of the carriage 3 is at the other end of the housing from that shown in FIG. 1. At that position, when an original document is placed on the upper surface of the platen glass 10 and the start button of the operation panel is pushed, the motor 42 rotates, and the carriage 3 travels toward the other end of the housing that includes the CVT glass 11 , that is, toward the right in FIG. 1, while the original document is being read. When the carriage 3 reaches a position slightly to the left of the position of the carriage 3 position shown in FIG. 1, the motor 42 rotates in the opposite direction, and the carriage 3 returns to the original position.
[0019] While the carriage 3 travels toward the right, the light source 34 illuminates the original document and an image of the original document is formed by light reflected from the original 5 document that passes through the rod lens array 32 . The light that passes through the rod lens array 32 forms an image at the CCD 33 . Then, the CCD 33 outputs to the controller 5 the image data that corresponds to the received light, and the controller 5 transmits the input image data to an image processor.
[0020] When the original document is set on the paper tray 20 , the controller 5 moves the carriage 3 to the right from the original position and stops the carriage when the sliding member 30 is at the position indicated by reference symbol B in FIG. 1. At this position, an image of the original document is read by the CCD 33 on the carriage 3 when the original document is sent from the paper tray 20 by the feeder 22 across the upper surface of the CVT glass 11 (hereinafter this position of the carriage 3 is referred to as the “CVT position B”).
[0021] [0021]FIG. 2A shows a diagram of the velocity v of the carriage 3 versus time t for the case of controlling the movement of the carriage 3 by technology developed prior to the present invention. As shown in FIG. 2A, the carriage 3 , which is stopped at the original position, is accelerated until reaching a prescribed speed, and then moves at a constant speed. Then, when the carriage 3 approaches the CVT position B, the speed of rotation of the motor 42 continuously decreases to decelerate the carriage until the carriage 3 is stopped at the CVT position B.
[0022] Further, when positioning of the original document on the platen glass 10 has been completed, the controller 5 accelerates the carriage 3 until reaching a constant speed by rotating the motor in the opposite direction. During that time, the carriage 3 travels to the left as shown in FIG. 1 at a constant speed until it stops at the original position after decelerating just prior to reaching the original position.
[0023] In the control of the movement of the carriage 3 described above, the sliding member 30 of the carriage 3 passes across the gap 12 a between the platen glass 10 and the CVT glass 11 at a constant speed, both when moving toward the CVT position B and toward the original position. At these times, because the sliding member 30 is pressed against the platen glass 10 and the CVT glass 11 , the sliding member 30 and the carriage 3 may be affected by the gap 12 a that exists between the platen glass 10 and the CVT glass 11 . It is possible that the changes in height of the carriage 3 at the gap 12 a and vibration of the carriage in that region may cause excessive wear of the sliding member 30 or loss of proper synchronization of movement of the carriage 3 with the operation of the motor 42 .
[0024] [0024]FIG. 2B shows a diagram of the velocity of the carriage 3 versus time for the case of controlling the movement of the carriage 3 of the entire image-reading device of FIG. 1, which is in accordance with the present invention. First, the carriage 3 that is stopped at the original position is accelerated to a constant speed. Then the carriage 3 continues to travel at the constant speed toward the position shown in FIG. 1. When the carriage 3 reaches a certain position in front of the CVT position B (i.e., the position where the sliding member 30 is at the point A in FIG. 1), the motor 42 operates to reduce the speed of the carriage 3 to a minimum speed that is relatively slow. The carriage 3 travels continuously at this slow speed and the sliding member 30 passes the adjacent edges of the platen glass 10 and the CVT glass 11 . Then, at the time the carriage 3 reaches the CVT position B, the rotation of the motor 42 is stopped. When this occurs, the inertial force of the carriage 3 is small because the carriage 3 is traveling at a slow speed. Therefore, there is no possibility of loss of synchronization even if the motor 42 is a stepping motor. In addition, since the slow speed of the carriage 3 is a suitable speed if the carriage 3 can be stopped at the same time that the motor 42 is stopped, the suitable slow speed may be faster than the minimum speed possible for the carriage. If the slow speed is half or less than the maximum speed, it is not necessary to use a special material for the sheet member 12 that bridges the gap 12 a, and any problems of vibration of the carriage 3 caused by the thickness of the sheet member at the gap 12 a are suppressed.
[0025] In order to move the carriage 3 from the CVT position B to the original position, the motor 42 is rotated in the opposite direction, and the carriage 3 passes the adjacent edges of the platen glass 10 and the CVT glass 11 at a slow speed. Then, when the sliding member 30 reaches point A, the motor 42 is accelerated to a constant speed. The carriage 3 then travels to the left at the constant speed and is stopped at the original position by being decelerated due to the operation of the motor 42 just prior to the carriage 3 reaching the original position.
[0026] As shown in FIG. 2B, in the image-reading device of the present invention, the carriage travels at one of two different constant speeds, one speed being less than one-half the other speed, during a significant portion of the time the carriage travels from one end of the image-reading device to the other end.
[0027] According to the construction of the image-reading device described above, when the sliding member 30 passes the edges of the platen glass 10 and the CVT glass 11 , the impact of any difference in levels of the platen glass 10 and the CVT glass 11 is small because the carriage 3 travels at a slow speed. Therefore, problems of wear of the sliding member 30 and loss of synchronization with the motor 42 can be prevented.
[0028] The use of MYLAR tape as the sheet member 12 , as described above, to connect the bottom surfaces of the platen glass 10 and the CVT glass 11 is particularly effective in reducing the impact of variations in levels of the platen glass 10 and the CVT glass 11 . Additionally, because the slow speed of the carriage 3 is a speed that has the ability to stop the carriage 3 at the same time the rotation of the motor 42 is stopped, the position of the carriage 3 can be precisely controlled.
[0029] The invention being thus described, it will be obvious that the same may be varied in many ways. For example, although, as described above, a rod lens array with a vertical optical axis is used, the optical axis can be directed differently. For example, the rod lens array may have its optical axis directed in the direction of movement of the carriage and receive light reflected by a mirror that receives light reflected from an original document. Additionally, although the invention as described above includes the light source to irradiate light onto the original document being mounted on the carriage, the light source may be separate from the carriage. Such variations are not to be regarded as a departure from the spirit and scope of the invention. Rather, the scope of the invention shall be defined as set forth in the following claims and their legal equivalents. 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. | An image-reading device includes a platen glass for supporting a document, an end glass adjacent to the platen glass, a sheet member that connects bottom surfaces of the platen glass and the end glass, a feeder for feeding a document to the image-reading device, a carriage that includes a sliding member, a rod lens array mounted on the carriage, and a photoelectric transfer device for reading an image of the original document formed by the rod lens array. The carriage is biased against the platen glass and the end glass through the sliding member and moves relative to them. A controller drives the carriage at different speeds, one less than half the other, so that the carriage is moving slowly when the sliding member contacts the sheet member, thereby avoiding problems of wear of the sliding member and loss of synchronism of the motor that drives the carriage. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is related to U.S. patent application No. entitled “High Strength Alloys for High Temperature Service in Liquid-Salt Cooled Energy Systems” which is being filed on even date herewith, the entire disclosure of which is incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] The United States Government has rights in this invention pursuant to contract no. DE-AC05-000R22725 between the United States Department of Energy and UT-Battelle, LLC.
BACKGROUND OF THE INVENTION
[0003] It is expedient to increase the efficiency of thermally based electricity generation in order to produce the maximum power while conserving resources. Any method of increasing said efficiency is inextricably linked to increasing the process temperature. The same fundamental association of higher temperatures with higher efficiency applies to all heat sources and power cycles. As the temperature of the process increases, the power cycle working fluid pressure concurrently increases. The high process pressure necessitates high strength containment materials.
[0004] The component under the most stress in nearly all thermally based power generation systems is generally the heat exchanger coupling between the low-pressure working fluid and the high-pressure power cycle fluid in indirect cycle systems, and between the combustion environment and the high-pressure power cycle fluid in direct cycle systems. Various temperatures and pressure differences are required across the heat exchanger regardless of the particular power cycle fluid selected (for example, molten salt, water, carbon dioxide, air, or helium) or heat source (for example, solar, nuclear, combustion). The high-temperature, high differential pressure heat exchangers for large power plants are large, expensive, and difficult to replace. Consequently, technologies for extending the life of such heat exchangers are of high value.
[0005] Conventional nickel-based super alloys are currently the leading structural material class for increased efficiency (high-temperature, high-pressure) power cycles. Conventional, well known precipitation strengthened nickel-based alloys exhibit both very high yield strengths and very high creep resistance. Although such alloys exhibit adequate oxidation resistance and resistance to combustion environments, they exhibit poor compatibility with both fluoride salts and alkali metals (the leading candidates for high temperature heat transport working fluids). Moreover, the microstructure—and consequently mechanical performance—of precipitation-strengthened alloys degrades at high temperatures over time necessitating component replacement or repair. Such degradation is accelerated by the application of external stress. Mitigation of degradation would be of high value.
BRIEF SUMMARY OF THE INVENTION
[0006] In accordance with one aspect of the present invention, the foregoing and other objects are achieved by a method of in-situ reconditioning a heat exchanger that includes the steps of: providing an in-service heat exchanger comprising a precipitate-strengthened alloy wherein at least one mechanical property of the heat exchanger is degraded by coarsening of the precipitate, the in-service heat exchanger containing a molten salt working heat exchange fluid; deactivating the heat exchanger from service in-situ; in a solution-annealing step, in-situ heating the heat exchanger and molten salt working heat exchange fluid contained therein to a temperature and for a time period sufficient to dissolve the coarsened precipitate; in a quenching step, flowing the molten salt working heat-exchange fluid through the heat exchanger in-situ to cool the alloy and retain a supersaturated solid solution while preventing formation of large precipitates; and in an aging step, further varying the temperature of the flowing molten salt working heat-exchange fluid to complete re-precipitate the dissolved precipitate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic diagram of a heat exchanger system.
[0008] FIG. 2 is a graph showing phase equilibria for Alloy 8 as a function of temperature (nitrogen and boron are not included in the calculations).
[0009] For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the above-described drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Of particular interest to this invention are precipitate-strengthened alloys. Some of the most suitable alloys are, for example, gamma-prime (γ′)-strengthened, nickel based alloys for application in high differential pressure heat-exchangers. Such alloys derive their high strength and good creep resistance through a combination of solid solution strengthening and through the precipitation of small, finely dispersed coherent intermetallic strengthening precipitates, γ′, which impede motion of dislocations. The compositions of these precipitates are typically of the form Ni 3 X where X can be Al, Ti, Nb, Ta or a combination of the foregoing. Alloys such as, for example, Nimonic 80A, IN 751, Nimonic 90, Waspaloy, Rene 41, Udimet 520, Udimet 720, and Alloy 617 are of interest to the invention.
[0011] The skilled artisan will recognize that various alloys containing other strengthening precipitates that behave in a similar manner to a γ′ precipitate also are of interest to the invention.
[0012] Of particular interest to the invention are alloys that are essentially Fe- and Co-free, and low in Cr content, which are described in U.S. patent application No. filed on even date herewith by Govindarajan Muralidharan, David E. Holcomb, and Dane F. Wilson, entitled “Creep-Resistant, Cobalt-Free Alloys for High Temperature, Liquid-Salt Heat Exchanger Systems”, the entirety of which is incorporated herein by reference.
[0013] The γ′ phase is typically produced through a multi-step heat-treatment process. The skilled artisan will understand that the steps described hereinbelow can be tailored to a specific alloy, component geometry, and application requirements for strength, hardness, and/or other durability aspects.
[0014] The first step is a solution-annealing heat-treatment wherein the alloy is heated to a temperature above the solvus temperature of the specific strengthening precipitate. Solvus temperatures of γ′ precipitates are typically in the range of 870-1100° C. depending on the composition of the alloy, hence requiring a maximum solution annealing temperature of no more than about 1150° C.
[0015] The solution annealing treatment is followed by a quenching step in which the alloy is rapidly cooled to a temperature at or below a working temperature, generally in the range of room temperature to 600° C. The effect of quenching is to is to retain the supersaturated solid solution and prevent unintentional growth of large precipitates at high temperatures during cooling.
[0016] A third step is a single or multi-step aging process, which promotes the growth of small strengthening precipitate microstructures. Aging is generally carried out in the range of 600-900° C. which results in the formation of fine intermetallic precipitates that provide the alloy with the required strength and creep resistance. Aging is generally carried out according to a time-temperature transformation curve that is specific to the alloy. Higher temperatures are used to promote faster precipitation, but less precipitate will form at higher temperatures. Aging can include in-service hardening.
[0017] The microstructure of precipitation-strengthened alloys degrades at temperature over time due to the coarsening (increase in the average size and interparticle spacing) of the strengthening γ′ phase, resulting in loss of yield and creep strength, thus necessitating component replacement or repair. Degradation is accelerated by mechanical stress. Degradation can be reversed by reconditioning the alloy; reconditioning is accomplished by repeating the multi-step heat-treatment process described herein, restoring initial precipitation-strengthening in the alloy. Heretofore, reconditioning has been carried out ex-situ; a component is removed from a service installation and taken to a heat treatment facility.
[0018] The invention comprises an in-situ reconditioning method to dissolve the γ′ precipitate and subsequent re-precipitation to regain the initial strength and creep resistance. The method can be repeated periodically over the lifetime of the component, thus prolonging life and avoiding replacement cost. Reconditioning is also known as rejuvenation with respect to the process used in the present invention.
[0019] The present invention is more preferably applicable to components fabricated from γ′ strengthened alloys and other strengthening precipitates that can be solution-annealed at temperatures of 1200° C. or below. Other precipitation strengthening phases, such as carbide strengthening, require solution-annealing heat-treatment at temperatures above 1200° C. to completely dissolve the precipitate phase and may prove to be relatively impractical to effectively implement in-situ due to (1) the difficulty of heating a component to such high temperatures and (2) the potential heat damage to other adjacent components and materials.
[0020] In accordance with examples of the present invention, the lower temperature required for dissolution and re-precipitation of the γ′ phase makes it quite feasible for periodical, in-situ, reconditioning of various components. For example during power-plant maintenance outages, power generation components can be reconditioned without removal from service installations.
[0021] FIG. 1 shows a typical tube-in-shell heat exchanger 10 , with a heat exchange tube 12 (normally an array comprising a multiplicity of tubes) containing a high-pressure power cycle fluid 14 . A low-pressure working fluid 16 outside the tube 12 is contained by the heat exchanger shell 18 . Arrows indicate flows of heat exchange fluids 14 , 16 during normal operation.
[0022] Examples of a working fluid 16 suitable for carrying out the method are various molten salt heat exchange compositions. One example is the low melt eutectic of KF-ZrF 4 ; analysis of phase behavior suggests the salt to be between 40 and 60 mole % KF with the balance ZrF 4 . An example of a favorable candidate salt composition is contemplated to be 53 mole % KF and 47 mole % ZrF 4 . Another example salt composition is NaF—ZrF 4 . Oak Ridge National laboratory Publication No. ORNL/TM-2006/69 by D. F. Williams, entitled “Assessment of Molten Salt Coolants for the NGNP/NHI Heat-Transfer Loop”, provides an assessment of the characteristics of various candidate salt compositions.
[0023] In accordance with examples of the present invention, a heating jacket 24 is disposed around the outside of the heat exchanger shell 18 . The heating jacket 24 can be comprised of resistance heaters, but the skilled artisan will recognize that various other, well known heating means such as fossil fuel combustion or induction could be used. The skilled artisan with further recognize that heating jackets are commonly used in liquid-salt-type heat exchangers in order to prevent solidification of working fluid during filling, thus the heat exchanger design does not generally need to be altered to allow the in-situ heat treatment.
[0024] The heat exchanger 10 is deactivated from service, but remains in-situ. The working fluid 16 can be the reconditioning fluid. Circulation of both the power cycle fluid 14 and the working fluid 16 are stopped for the reconditioning process. The power cycle fluid 14 can be removed from the tube 12 during the reconditioning process to prevent excess pressure, or the pressure can be lowered by a pressure relief valve. Auxiliary heating of the working fluid 16 circuit outside the heat exchanger 10 may be necessary to maintain the fluidity thereof.
[0025] In a first, solution-annealing step, the heating jacket 24 is activated in order to elevate the temperature of the heat exchanger 10 to a temperature that is above the solvus temperature of the composition of the alloy of which the heat exchanger 10 is comprised. The static working fluid 16 (or another reconditioning fluid) assists in transferring the heat to all parts of the heat exchanger 10 , including the heat exchange tube 12 , thus solution-annealing all the parts of the heat exchanger 10 in-situ. The elevated temperature is maintained for a sufficient duration to completely solution-anneal the heat exchanger 10 as described hereinabove, effectively dissolving essentially all of the γ′ precipitate phase. The duration will depend on the alloy composition, solution-annealing temperature, and cross-section thickness.
[0026] In a second, quenching step, after solution-annealing is complete, the heating jacket 24 is deactivated and flow of the working fluid 16 is rapidly restarted to quench the alloy of the heat exchanger 10 to a temperature below the working temperature of the heat exchanger 10 and preferably to the lowest temperature at which the working fluid will remain sufficiently fluid to flow. Quenching allows retention of the elements required for the formation of the precipitates within the supersaturated solid solution and prevents unintentional growth of large precipitates at high temperatures during cooling.
[0027] A third aging step, following the quenching step, completes the re-precipitation of the γ′ precipitate phase. The temperature is raised from the quenching temperature, preferably to a maximum temperature no greater than the normal operating temperature of the heat-exchanger 10 , in order to facilitate precipitation of the desired microstructures. Aging of the heat exchanger alloy can be carried out in-service by monitoring and varying the flow and temperature of heat exchange fluids 14 , 16 through the heat exchanger to achieve desired aging temperatures and times. The heating jacket 24 and/or auxiliary heating may also be used in the aging process. The skilled artisan will recognize that aging can comprise one or a plurality of steps. The alloy of the heat exchanger 10 is thus reconditioned in-situ. The pressure of the power cycle fluid 14 must be controlled until the heat exchanger alloy strength is sufficiently restored to withstand high pressure.
[0028] The in-situ heat-treatment process can be repeated throughout the facility lifetime greatly extending the heat exchanger lifetime. A possibility of an eventual limitation to repeating the in-situ heat treatment may be caused by a potential loss of aluminum in the alloy through preferential dissolution of aluminum from the alloy into the liquid salt. The Gibbs free energy of AlF 3 is sufficiently low that it will rapidly dissolve into fluoride salts. Hence, sufficient excess aluminum or diffusion barriers are recommended in the initial composition so that many years of solid-state diffusion will be required to deplete the aluminum from the alloy. Titanium loss may also need to be monitored and/or controlled in a similar fashion.
Example
[0029] A heat exchanger is fabricated using Alloy 8 described in the patent application referenced hereinabove, expressed in weight %:1.23 Al-6.56 Cr-0.74 Mn-11.78 Mo-2.43 Ti-0.01 Nb-0.56 W-0.031 C-0.0003 N-balance Ni. The heat exchanger is installed in a system where it is used in service using a molten salt working heat exchange fluid comprising about 53 mole % KF and about 47 mole % ZrF 4 . After remaining in service for a sufficient time to render the heat exchanger in need of reconditioning, the heat exchanger is taken out of service and isolated from the system by closing appropriate valves and shutting off coolant pumps, with the molten salt remaining inside the heat exchanger.
[0030] Pressure is lowered on the high pressure side of the heat exchanger by opening a pressure relief valve. By energizing a heating jacket around the heat exchanger, the temperature of the heat exchanger (and the molten salt contained therein) is raised to 1121° C. and held for 4 hours to solution-anneal the alloy of the heat exchanger.
[0031] Subsequently, the heating jacket is de-energized. Valves are reopened and coolant pumps are restarted, causing molten salt working heat exchange fluid to flow, reducing the temperature of the heat exchanger to 550° C. as quickly as is reasonably feasible in order to quench the alloy of the heat exchanger.
[0032] Aging of the heat exchanger alloy is carried out in-service by monitoring and varying the flow and temperature of heat exchange fluid through the heat exchanger (including re-energizing the heating jacket if required) to achieve desired aging temperatures and times. The heat exchanger is thus reconditioned.
[0033] Pressure is restored on the high pressure side of the heat exchanger by closing the pressure relief valve, and the heat exchanger is returned to service.
[0034] Referring to FIG. 2 , For Alloy 8, The working temperature range of a typical molten salt working heat exchange fluid can be temperature B, about 650° C., to temperature C, about 850° C. The first, solution-annealing step, can be carried out above the solvus temperature D, which is about 880° C. Temperature E, about 1150° C. is a practical maximum above which sacrifices in energy usage and other deleterious effects may occur. In the second, quenching step, the temperature can be lowered below temperature A, which is about 600° C. The lower limit is the temperature at which the molten salt working heat exchange fluid freezes or becomes deleteriously viscous. Aging, the third step, can be carried out by heat-treatment at various temperatures between temperature A and temperature C, and preferably at a maximum temperature no greater than the normal operating temperature of the heat-exchanger.
[0035] While there has been shown and described what are at present considered to be examples of the invention, it will be obvious to those skilled in the art that various changes and modifications can be prepared therein without departing from the scope of the inventions defined by the appended claims. | A method of in-situ reconditioning a heat exchanger includes the steps of: providing an in-service heat exchanger comprising a precipitate-strengthened alloy wherein at least one mechanical property of the heat exchanger is degraded by coarsening of the precipitate, the in-service heat exchanger containing a molten salt working heat exchange fluid; deactivating the heat exchanger from service in-situ; in a solution-annealing step, in-situ heating the heat exchanger and molten salt working heat exchange fluid contained therein to a temperature and for a time period sufficient to dissolve the coarsened precipitate; in a quenching step, flowing the molten salt working heat-exchange fluid through the heat exchanger in-situ to cool the alloy and retain a supersaturated solid solution while preventing formation of large precipitates; and in an aging step, further varying the temperature of the flowing molten salt working heat-exchange fluid to re-precipitate the dissolved precipitate. | 5 |
BACKGROUND OF THE INVENTION
This invention relates to a differential pressure, thermoforming machine and more particularly to a differential pressure, forming machine having new and novel apparatus for incrementally advancing a sheet of plastic through the machine.
Differential pressure forming machines, such as that disclosed in U.S. Pat. No. 3,496,257 granted to G. W. Brown, et al., on Feb. 17, 1970 and U.S. Pat. No. 3,664,791, granted to G. W. Brown on May 23, 1972, have pairs of laterally spaced, longitudinally extending chains for advancing sheets of plastic therethrough. These patents disclose a drive system for the sheet support chains comprising a cooperating drive rack and pinion gear, the rack being reciprocally driven by the piston of a fluid operated cylinder. A clutch is provided for coupling and decoupling the pinion gear to the sheet support chains so that the sheet support chains are incrementally forwardly indexed. Many problems are associated with the use of such gear racks. The prior art drive rack system is difficult to maintain and difficult to keep properly adjusted. Accordingly, it is an object of the present invention to provide a differential pressure thermoforming machine of the type described which includes a new and improved drive train for incrementally forwardly indexing the sheet support chains.
Trimming devices are commonly mounted in-line and downstream of a thermoforming mold to trim the formed part from the remainder of the sheet. It is important to index the sheet the same distance so that the in-line trimming apparatus will properly trim the part. The prior art gear rack incorporated relatively expensive and complicated damper mechanism for damping the inertia built up during the sheet advancing stroke. Such damping apparatus is difficult and expensive to maintain. Accordingly, it is an object of the present invention to provide a differential pressure forming machine including a sheet indexing system which is simpler, less expensive to construct and easier to maintain in adjustment.
It is another object of the present invention to provide a differential pressure thermoforming machine of the type described including a drive train which has improved stroke cushioning capabilities.
Yet another object of the present invention is to provide a differential pressure thermoforming machine of the type described including a new and improved drive train having new and improved apparatus for controlling the stroke length.
Another object of the present invention is to provide, in a differential pressure thermoforming machine, a new and improved drive train for the sheet advancing chains including a drive chain driven in a to-and-fro path of travel by the pistons of a pair of fluid operated cylinders coupled to opposite ends of the drive chain.
Still another object of the present invention is to provide a differential pressure forming machine including a pair of fluid operated oppositely operating drive cylinders, drive mechanisms one of which dampens the travel of the other.
Yet another object of the present invention is to provide a differential pressure forming machine of the type described including a pair of fluid driven cylinders having pistons for driving a drive chain in a to-and-fro path of travel and including mechanism for eliminating slack in the drive chain.
The present invention may more readily be understood by reference to the accompanying drawings in which:
FIG. 1 is a side elevational view of a differential pressure forming machine constructed according to the present invention;
FIG. 2 is a sectional, top plan view, taken along the line 2--2 of FIG. 1; and
FIG. 3 is a schematic diagram illustrating pneumatic and electrical control circuit for controlling the apparatus illustrated in FIGS. 1 and 2.
Other objects and advantages of the present invention will become apparent to those of ordinary skill in the art as the description thereof proceeds.
SUMMARY OF THE INVENTION
A differential pressure forming machine comprising a heater for heating a moldable, thermoplastic sheet to a forming temperature, a mold for applying differential pressure to the heated sheet to form a shape therein, a pair of endless, laterally spaced, longitudinally extending sheet support members for supporting the sheet and sequentially moving the sheet to the heater and to the mold, a drive chain for driving the support chains, a pair of fluid receiving cylinders mounting pistons which are coupled to opposite ends of a drive chain for driving the chains in a forward and reverse path of travel, and a clutch for coupling said drive chain to the driven chains only when the drive chains move in one of the forward and reverse paths of travel to incrementally index the sheet to the heater and to the mold.
DESCRIPTION OF THE INVENTION
A differential pressure forming machine constructed according to the present invention is generally designated 8 and includes a frame, generally designated F, including upper and lower longitudinally extending frame members 10 and 12 spanned by vertical end frame members 14 and upper and lower end cross members 16. The frame F also includes a pair of side rails 18, supported on the end cross member 16 via vertical posts 21, journalling at opposite ends thereof a pair of rotary shafts 20 mounting laterally spaced sprocket wheels 22. A pair of laterally spaced, longitudinally extending, endless, sheet supporting chains 24 are trained around the sprocket wheels 22 for carrying a continuous sheet or web of thermoplastic material, such as polyethylene, generally designated S (FIG. 1). The chains 24 mount sheet penetrating pins 26 such as that disclosed in U.S. Pat. No. 3,664,791, granted to Mr. G. W. Brown on May 23, 1972, which patent is incorporated herein by reference.
Mounted on the frame F is a heater assembly, generally designated 28, for heating the thermoplastic sheet S to a forming temperature. The heater 28 includes side frame members 30, mounted on the upper side rails 10, spanned by cross bars 34 which mount banks of electrically powered heaters 32. The heater 28 also includes an additional bank of electrically powered heaters 36 mounted on cross bars 38 which are supported by the side frame members 10 for assisting the heaters 32 to bring the sheet S to a forming temperature.
Mounted downstream of the heater 28 is a differential pressure mold assembly, generally designated 40, including an upper, female die box assembly, generally designated 42, and a lower male die box assembly, generally designated 44 on the underside of the sheet S. The mold assembly, generally designated 40, is mounted on a sub-frame, generally designated F' including upstanding side rails 45 supported by the frame side rails 10, mounting upper and lower pneumatically operated cylinders 46 and 48 having piston rods 50 and 52 respectively in a manner disclosed more particularly in U.S. Pat. No. 3,496,257, granted to G. W. Brown on Feb. 17, 1970 which is also incorporated herein by reference. The mold assembly 40 is more particularly described in the aforementioned U.S. Pat. No. 3,496,257 and will not be repeated in detail herein.
The apparatus for sequentially, incrementally forwardly indexing the sheet support chains 24 is generally designated 60 and includes a frame supported clutch assembly, generally designated 62, having one clutch plate 64 coupled to the shaft 20 and a cooperating clutch plate 66 mounting a sprocket wheel 68. The clutch assembly 62 is schematically illustrated and is more particularly illustrated in U.S. Pat. No. 3,217,852, granted to G. W. Brown, et al. on Nov. 16, 1965, which is incorporated herein by reference. The clutch assembly 62 may also comprise a jaw type clutch, commonly known as a Horton clutch.
Apparatus for driving the clutch sprocket wheel 68 comprises a link chain 70, trained around the sprocket wheel 68, having one end 72 coupled to a piston rod 74 mounted on an advance piston 76 received in an advance, pneumatically operated, double acting cylinder 78 which is mounted on one of the side rails 18. The opposite end 80 of the drive chain 70 is coupled to a piston rod 84, mounted on a retract piston 86 (FIG. 3), slidably received by a return cylinder 88 which is also mounted on one of the side rails 10. An adjustable stop 87 is threadedly received in an end wall 89 of the return cylinder 88 for adjustably controlling the length of index or return stroke of piston 86. A limit switch LS-1 is mounted on the upstanding side frame rail 45 and is actuated by the upper mold 42 when the upper mold 42 is in the raised position. A limit switch LS-2 is mounted on the frame side rail 18 in the path of return piston rod 74 and is actuated when return piston rod 74 is fully extended.
FLUID AND ELECTRICAL CONTROL CIRCUIT
The fluid and electrical control circuit, for controlling the operation of the thermoforming apparatus illustrated in FIGS. 1 and 2, is illustrated in FIG. 3. Firstly, the fluid control circuit includes an air supply line 90 for supplying pressurized air from a source A to a two position, solenoid actuated, fluid control valve, generally designated 92, via a conduit 94. When the spool 93 of valve 92 is in the position illustrated in FIG. 3, pressurized air will be delivered to a conduit 96 which supplies pressurized air to one end 98 of the return cylinder 88 for driving the return piston 86 from a start position illustrated in FIG. 3 to an end position illustrated in chain lines in FIG. 3. Connected in fluid line 96 is a check valve 100 which permits the free flow of air to the end 98 of return cylinder 88 when the valve 92 is in the position illustrated in FIG. 3. Valve 100 precludes the reverse flow of air therethrough when flow control valve 92 is in the "cross-over" position. Also, connected in parallel with the check valve 100 is an adjustable, flow control valve 102 for cushioning the flow of air out of the return cylinder end 98 when air is supplied to the advance cylinder 78 as will immediately become apparent.
The valve 92 includes a solenoid 92a for shifting the spool 93 of the valve 92 to the "crossover" position in which line 96 is coupled to an exhaust 104 for permitting air in the return cylinder end 98 to be exhausted via line 96 and the control valve 102.
When the valve 92 is in the position illustrated in FIG. 3, the exhaust 104 is coupled to the end 106 of advance cylinder 78 via a line 108. Coupled in line 108 is a check valve 110, which permits the free flow of pressurized air from line 94 to the advance cylinder end 106 when the control valve 92 is in the cross-over position. Connected in parallel with the check valve 110 is an adjustable, flow control valve 112 which restricts and controls the flow of air from the advance cylinder end 106 to the exhaust 104 when the valve 92 is in the position illustrated in FIG. 3. The check valves 110 and 100 are so constructed as to not permit the reverse flow of air therethrough. A check valve 111 is provided in the opposite end wall 114 of advance cylinder 78 and permits the free flow of air, encased in the opposite end 116 of advance cylinder 78, when the piston 76 is moved from a start position illustrated in FIG. 3 to a finish position illustrated in chain lines in FIG. 3. The check valve 111 precludes the reverse flow of air therethrough so that a vacuum will build in the advance cylinder end as the advance piston 76 returns from the finish position to the start position.
As is illustrated in FIG. 3, the clutch 62 includes a pneumatically operated cylinder 118 mounting a piston 122 which is coupled to the clutch plate 66 for selectively moving the clutch plate 66 into driving engagement with the opposite clutch plate 64. A spring, schematically designated 117, normally maintains the clutch plates in spaced relation. Air is supplied from line 90 to the cylinder 118 via the control valve 123 including a valve spool 124 and a solenoid 122a which will move the valve spool 124 against the biasing force of spring 117 from the position illustrated in FIG. 3 to the chain line position illustrated in FIG. 3. When the valve spool 124 is in the position illustrated in FIG. 3, the clutch plate 66 is spring biased away from the clutch plate 64 and power transmitted to the sprocket wheel 68 is not transmitted to the shaft 20 or sheet carrying chains 24. When the valve spool 124 is moved to the position illustrated in chain lines, pressurized air is supplied from line 90 to the cylinder 118 to force the plates 66 and 64 into driving engagement and the power transmitted to the sprocket wheel 68 will be coupled to the drive chains 24 to forwardly index the chains 24 and the sheet S carried thereby.
The electrically control circuit for operating the apparatus illustrated in FIGS. 1 and 2 is also illustrated in FIG. 3, and includes a pair of input circuit lines L1 and L2 connected to a suitable source of power such as 110 volt alternating current. A plurality of circuit lines L3 through L7 are connected across the lines L1 and L2. The circuit line L3 is connected across lines L1 and L2 and includes a set of limit switch contacts LS-1a of a limit switch LS-1 which is actuated when the upper mold 42 is fully retracted to the raised position illustrated in FIG. 1.
The normally open contacts LS-1a are connected in series with the valve actuating solenoid 92a, the clutch actuating solenoid 122a and a pair of normally closed limit switch contacts LS-2a included with the limit switch LS-2 mounted on the side frame member 10. The normally closed limit switch LS-2a are opened when the piston 86 of return cylinder 88 is fully extended. When the limit switch contacts LS-2a are opened, current flow to the solenoids 92a and 122a is interrupted.
Connecting across lines L1 and L2 is a circuit line L4 including a set of normally open limit switch contacts LS-2b and parallelly connected solenoids 46a and 48a for controlling valves (not shown) which deliver pressurized air to the upper and lower sides of the upper and lower cylinders 46 and 48 respectively to move the molds 42 and 44 to closed positions, clamped to opposite sides of the plastic sheet S. A set of normally closed timer contacts T1 is also connected in circuit line L4. Connected in line L5 across the lines L1 and L2 is a timer T and a set of normally open contacts LS-2c which close when the limit switch LS-2 is tripped.
Connected in lines L6, across the lines L1 and L2 are a set of normally open timer contacts T2, which close a predetermined time after the timer T is energized, and parallelly connected solenoids 46b and 48b which operate valves to retract the mold driving pistons 50 and 52 of cylinders 46 and 48 respectively to withdraw the molds 42 and 44 to the remote positions. The timer also includes the set of timer contacts T2 connected in line L4.
THE OPERATION
Assuming that a forming cycle has just been completed and the molds 42 and 44 retract to the positions illustrated in FIG. 1, the limit switch LS-1 will be actuated to close the contacts LS-1A (Line L3) to energize the valve control solenoids 92a and 122a. A continuous sheet S of plastic is carried by the sheet support chains 24. When the solenoid 92a is energized, the valve spool 93 of valve 92 will move to the "crossover" position and pressurized air will be supplied from air supply line 90 to line 108 via the check valve 110 to drive the advance cylinder 76 from the start position, illustrated in FIG. 3, to the left in a direction represented by the arrow X (FIG. 3). When the solenoid 122a is energized, the spool 124 of valve 123 is moved to the position illustrated in chain lines in FIG. 3 and pressurized air will be supplied to the clutch control cylinder 118 so that the clutch plate 66 will be drivingly coupled to the clutch plate 64. As the advance piston 76 is moved in a direction of the arrow X, the drive chain 70 will move therewith in the direction of the arrow X to rotate the sprocket wheel 68 and clutch plate 66 clockwisely as viewed in FIG. 1. As the chain 70 negotiates the sprocket wheel 68, it will draw the piston rod 84 and piston 86 of the return cylinder in the direction of the arrow Y. This will force fluid from the return cylinder end 98 through flow control valve 102 to exhaust port 104.
As the advance cylinder piston 76 is moved to the left in the direction of the arrow X, the air in the return cylinder end 98 will automatically operate as a dampener to dampen movement of the advance piston 76 because the passage of air from return cylinder end 98 will be restricted by the flow control valve 102. The dampening of return piston 86 precludes the bottoming out of advance piston 76 against the cylinder end wall 114. This circuit arrangement eliminates necessity for additional hydraulic dampeners and deceleration valves.
When the return piston rod 84 is fully extended, it will trip the limit switch LS-2 to close the normally open limit switch contacts LS-2b (line L4) and LS-2c (line L5) and open the normally closed contacts LS-2a (line L3). When the limit switch contacts LS-2a are opened, the air control valve 92 is spring returned to the position illustrated in FIG. 3 and pressurized air is coupled from line 90 to the retract cylinder end 98 of return cylinder 88 via the check valve 100. This will force the retact piston 86 in an opposite direction represented by the arrow W and pull the drive chain 70 therewith in a direction so as to rotate the sprocket wheel 68 counterclockwisely as illustrated in FIG. 1. The return piston 86 can be returned to a much slower rate than the rate of advance of the piston 76 because there is substantially more time available for return during the forming cycle.
At the same time, the piston rod 74 and advance piston 76 are moved in the opposite direction Z to force air remaining in the advance cylinder end 106 through the flow control valve 112 to the discharge exhaust port 104. At this same time, the valve control solenoid 122a is de-energized and the spool 124 of valve 122 will return to the position illustrated in FIG. 3 and the coil spring, schematically designated 117, will force the clutch control piston 120 to the left, as illustrated in FIG. 3, to separate the clutch plates 66 and 64 and decouple the drive chain 70 from the sheet support chains 24. Accordingly, although the chain 70 is driven in a reverse path of travel, the sheet support chains 24 are not reversely driven. Since the clutch is now de-energized, the inertia of the system during the return (arrows W and Z) is substantially less because the sheet and sheet support chains are not being moved. Only the inertia of the chain and cylinders is involved and thus the dampening is not as critical, but the passaged air from advance cylinder end 106 through flow control valve 112 will dampen the return movement of retract piston 86. At the end of its return travel, the retract piston 86 merely abuts the stop 87. The length of the following indexing stroke can be adjusted if desired by rotating the screw of stop 87.
The molds 42 and 44 are moved to a closed position when the normally open contacts LS-2b (line L4) are closed to energize the mold advance solenoids 46a and 48a. When the limit switch contacts LS-2c (line L5) close, the timer T (line L5) is energized. After a predetermined forming cycle is completed, the contacts T1 (line L6) close to energize the retract solenoids 46b and 48b so that the molds 42 and 44 are retracted to the removed positions illustrated in FIG. 1. At the same time, the normally closed timer contacts T2 (line L6), are opened to interrupt circuit line L4. When the solenoids 46b and 48b are energized, the molds 42 and 44 are returned to their raised positions to again close the limit switch LS-1 and the cycle is again repeated. The flow control valves 102 and 112 can be adjusted to control the speed of the advance and the speed of return.
When the advance cylinder 76 moves to the left in the direction of the arrow X, air entrapped therein can move outwardly through the check valve 111. When the advance piston 76 is drawn to the right, in the direction of the arrow Z, the check valve 111 precludes the reverse flow of air to the advance cylinder end 116 and maintains a vacuum in the cylinder end 116. The vacuum will tend to build as the chamber 116 expands. This will tend to maintain tension on the chain 70 and keep the chain tight and prevent slack from developing in the chain.
The operator can adjust the stroke by merely rotating the screw thread stop 87 inwardly or outwardly in the return cylinder 88.
It is to be understood that the drawings and descriptive matter are in all cases to be interpreted as merely illustrative of the principles of the invention, rather than as limiting the same in any way, since it is contemplated that various changes may be made in various elements to achieve like results without departing from the spirit of the invention or the scope of the appended claims. | A differential pressure forming machine including a pair of endless, sheet supply chains for supporting a deformable thermoplastic sheet and forwardly advancing the sheet, a heater for heating the thermoplastic sheet, a mold for differential pressure forming a shape in the heated sheet, a drive chain for driving the sheet supply chains, a clutch for selectively coupling and decoupling the drive chain and the supply chains, a pair of pneumatic cylinders mounting reciprocally movable pistons which are coupled to opposite ends of the drive chain for driving the sheet support chains in forward and reverse paths of travel, and control mechanism for operating the clutch and the pistons in timed relation so that the sheet support chains and the sheet are incrementally indexed only when the chain moves in said forward path of travel. | 8 |
CROSS REFERENCE TO A RELATED APPLICATION
[0001] The present application is a division of U.S. patent application Ser. No. 12/800,864, filed on May 24, 2010.
[0002] The present application contains a subject matter which is similar to a part of the subject matter of the above identified earlier patent application, from which it claims its priority under 35 USC 119 (a)-(d), and which is incorporated in the present application by reference thereto.
BACKGROUND OF THE INVENTION
[0003] The present invention relates to catalysts for purification of gaseous condensate and oil fractions from mercaptans and can be used in oil-processing and in petrochemical industry.
[0004] Usually oxidation of mercaptans is performed by oxygen or air at room or elevated temperature in the presence of homogenous or heterogeneous catalyst based on a transitional metal:
[0000] 2RSH+½0 2 →RSSR+H 2 0
[0005] Mercaptans are extracted from organic phase by strongly alkali aqueous solutions, in which .at elevated temperature and pressure catalytical oxidation of mercaptans takes place, and as a catalyst salts from metals of alternating valency (Fe, Co, Ni, V, Mn, Cr) in the form of simple or complex compositions, more often phatocyanites (as disclosed for example in European patent no. 394571, German patent 3008284 and others). The catalysts of this type provide sufficiently complete removal of mercaptans. Their common disadvantage is not sufficient availability and high cost of phatocyanites, which leads to making the process of purification expensive. Moreover, the necessity to conduct the process in strongly-alkli medium leads to a significant corrosion of equipment and worsening of the properties of oil pipelines.
[0006] It is known that phtalocyanines in catalytical compositions can be replaced with other compounds of transitional metals.
[0007] A catalyst are known based on metallo-organic derivatives of metals of VIA, VIIA, and VIII groups with general formula Me a (R)×(CO)y where R is aromatic ligand, for example benzol or its alkyl derivatives, antrazen, benzpirin, phenanthren (U.S. Pat. No. 3,053,756). Disadvantages of such catalysts include their low stability, high cost and toxicity.
[0008] A catalyst for oxidating demercaptanization of carbohydrates is known which is a helate complex of a transitional metal with bi, tri, or tetra dentant ligand, containing at least one amide group (French patent 2,573,087). In particular, replaced 2-(alkyl(aryl, aklylary))-aminocarboxypyriditines and others even more complicated compounds are utilized. As a metal it can be Co, Fe, Cu, Ni, Mn. The disadvantage is a low stability of the catalyst and use for its manufacture of expensive and scarse components.
[0009] Also, catalysts of oxidating demercaptanization are known-complexes of copper with tetracyantiophenol and tetracyandentin (French patent 2591610). These catalysts provide high degree of purification, but their practical use is questionable because their very high cost and scarse availability of the components.
[0010] A method of oxidative demercaptinization are known which is performed by oxidation of mercaptans with oxygen of air in presence of helate complexes of a transitional metal (Co, Fe, Cu, Ni, Mn) with polydentan ligand from the class of amides, in particular from aminocarboxyperidines (French patent 2573087). The main disadvantage of the method with the use of this catalyst is high cost of its components.
[0011] A heterogeneous catalyst is described, based on complexes of copper with amino derivatives (aminoalcohols, aminoacids, amines) applied on a mineral carrier or activated coal (European patent 996500). The disadvantage of this catalyst is a low content of active phase on the surface of the carrier, which inevitably leads to a significant consumption of the heterogeneous catalyst.
[0012] The closest solution to the present invention is disclosed in U.S. Pat. No. ______. In accordance with this patent, a catalyst of alkali-free purification of oil fractions from mercatans is proposed, which contains a copper oxide, a complex of copper with nitrogen-containing compound of amines, aminoalcohols, aminoacids, or amids and an inert carrier. The disadvantage of this method is a complex technology for producing catalyst and a high consumption of the carrier, which makes the catalyst quite expensive.
SUMMARY OF THE INVENTION
[0013] The objective of this invention is to reduce the cost of a catalytic composition by eliminating utilization of a mineral carrier and using solid or liquid complexes which contain a copper chloride, aminoalcohol and acetonitryl or single-atom alcohol selected from isopraponal, butanol, isobutanol, and pentanol.
[0014] In accordance with the invention a catalyst is proposed for alkali-free purification of oil raw materials, consisting of a metalocomplex selected from the group consisting of a solid metalocomplex and a liquid metalocomplex with a general formula (Cu II Cl) 2 O(L 1 ) 2−4 (L 2 ) 1−4 , where L 1 is amino alcohol, L 2 is acetonitryl or single atom alcohol.
[0015] in accordance with a further feature of the invention as the aminoalcohol a compound of a general formula N(R 1 )(R 2 )(R 3 )(OH) 1−3 is utilized, where R 1 ═C 2 H 4 , R 2 ═H, C 2 ═H, C 2 H 4 , C 2 H 5 , R 3 ═H, C 2 H 4 , C n H 2n+1 , where n=2-17.
[0016] In accordance with still a further feature of the invention as a single atom alcohol a substance selected from the group consisting of isopropanol, butanol, isobutanol and pentanol is utilized.
[0017] The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims.
[0018] The invention itself, however, both as to its composition and its method of use, will best best understood from the following description of the preferred embodiments, which is accompanied by examples of realization.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The present invention resides, in a catalyst for purification of oil raw material with the use of a metalocomplex of general formula (Cu II Cl) 2 O(L 1 ) 2−4 (L 2 ) 1−4 , wherein L 1 is amino alcohol of the general formula N(R 1 )(R 2 )(R 3 )(OH) 1−3 , wherein R 1 ═C 2 H 4 , R 2 ═H, C 2 H 4 , C 2 H 5 , C 2 H 5 , R 3 ═H, C 2 H 4 , C n H 2n+1 , wherein n=2-17, L 2 is acetonitryl or the above mentioned alcohol.
[0020] The metal complex is synthesized in acetonitryl or alcohol starting from CuCl and aminalcohol at 45-50° C. in air.
[0021] The catalyst actively oxidizes mercaptans and hydrogen sulfide with oxygen of air at temperature 22-120° C. and at atmospheric pressure.
[0022] The objective of the present invention can not be achieved if at least one of the above mentioned components of catalytic complex are not used or the conditions of synthesis are not complied with, for example:
If instead of copper chloride CuCl2 is used or another salt is used (nitrate, sulfate, stearate, etc.) If amino alcohol is not used, the complex is not active; If as a solvent acetylnitryl or alcohol is not used, the activity of catalyst is reduced. For example, if acetylnitryl is replaced with chloroform, the activity of catalyst is reduced three times.
[0026] Therefore, the present invention resides in a catalyst of oxidating alkali-free demercaptanization of oil, gas condensate or oil fraction based on a metalocomplex of the above mentioned composition.
[0027] The present invention is illustrated by the following examples.
EXAMPLE 1
Producing of Solid Metalocomplex
[0028] 100 ml of saturated solution of CuCl in acetonitryl (the solution contains 8 g of CuCl) is introduced into a flat-bottom container of 200 ml at room temperature, and heated to 45-50° C. With continuous steering by a magnetic stirrer, slowly (in 30-40 min) from a peeped 20 ml of solution of monoethanolamine in acetonenitryl is introduced into the container (solution is prepared by mixing of 17 ml of monoethanolamine and 100 ml of acetonitryl).
[0029] The precipitated substance of blue-green color is separated from a mother solution on a filter, dried on air and then in a drying cabinet at 100-105° C. The obtained dry complex contains 9.2-9.5 g. Before testing the solid catalyst is comminuted in a porcelain dish. This way, catalyst A is produced. Catalyst B and C were produced analogously, but instead of monoethanolamine, dimethylamineethanol ethanol and three ethanolamine were utilized
EXAMPLE 2
Production of Liquid Metalocomplex D-F
[0030] 20 ml of aminoalcohol Atmer 163 which is a mixture of isomers with the composition RN(CH 2 CH 2 OH) 2 , where R═C n H 2n+1 n=16-17 and 20 ml isobutanol is introduced into a flat bottom container. During mixing and heating to 45-50° C. in air, slowly log CuCl is added. As a result, a dark-brown dense liquid is produced. Before testing, the obtained liquid complex D is dissolved in an excessive quantity of isobutanol to concentration Cu(II) 1-1.5%. Catalyst E and F are produced analogously, but instead of isobutanol, butanol and isopropanol were added.
EXAMPLE 3
Production of Liquid Metalocomplex H
[0031] 20 ml of triethanolamine and 10 ml of pentanol are introduced into a flat bottom container. During heating and mixing to 50-55° C., slowly 12 g CuCl is added. As a result, a dark-green dense liquid is formed. Before testing the obtained liquid complex H is dissolved in an excessive quantity of pentanol to concentration Cu (II) 1.15%.
EXAMPLE 4
Purification of Kerosene on Solid Catalyst
[0032] A reactor with a magnetic stirrer is utilized, which is formed as a four-neck flat-bottom container with volume of 350 ml, composed OF molybdenum glass and provided with swdlwfmROE, a system of air and oxygen supply and a glass pipe for taking samples A kerosene fraction with a content of mercaptide suffer 80 ppm, a batch of catalyst A (ratio of raw material to catalyst is 62000 ml/g) and Teflon magnetic stirrer were are introduced. The reaction time was four hours. During this time the content of sulfur was reduced to 30 ppm. The samples were taken with interval of 0.5 hour.
EXAMPLE 5
Purification of Fuel Oil of Gas Condensate on Solid Catalyst
[0033] The process was conducted as in Example 2 but instead of kerosene, fuel oil from gas condensate was used, which contained 1200 ppm of mercaptide sulfur (a gas condensate was used which was distilled in interval 56-354° C. with density 0.77 g/cm 3 and content of moisture 0.04% mass). The ratio of raw material to catalyst was 7000 ml/g. The temperature of reaction was 120° C. In 1 hour the concentration of sulfur was reduced to 590 ppm.
[0000]
TABLE 1
Test results of purification of kerosene and gas condensate
on solid catalyst.
Ratio of
raw
material:
Content of Mercaptan
Petroleum
Catalytical
sulfur, ppm
product to
Solution
Temperature
In Raw
After the
Catalyst
be Purified
(ml/Ml
° C.
Material
Reaction
A
Kerosene
120000
70
80
4 hours-20
A
Kerosene
62000
22
80
10 hours-40
A
Fuel Oil
7000
45
1200
10 hours-800
B
Kerosene
62000
70
80
4 hours-25
B
Fuel Oil
7000
120
1200
2 hours-450
C
Kerosene
100000
70
80
4 hours-25
EXAMPLE 6
[0034] Purification of fuel oil from gas condensate with the use of liquid catalyst.
[0035] Liquid complex D is dissolved in an excessive quantity of isobutanol to concentration Cu (II) 1%. Into the reactor described in Example 4, fuel oil was introduced with content of mercaptide sulfur 1200 ppm. The ratio of raw material to solution of catalyst 2000 ml/ml. Temperature of reaction was 100° C. In two hours the concentration of sulfur reduced to 550 ppm.
[0036] With increase of concentration of liquid complex in isobutanol to Cu (II) 1.5%, with the same conditions in 2 hours the concentration of sulfur reduced to 450 ppm.
[0000]
TABLE 2
Test results of purification of kerosene and gas condensate with the
use of liquid metalocomplex.
Ratio of
raw
material:
Content of Mercaptan
Petroleum
Catalytical
sulfur, ppm
product to
Solution
Temperature
In Raw
After the
Catalyst
be Purified
(ml/Ml
° C.
Material
Reaction
D
Kerosene
100000
70
80
3 hours-20
E
Kerosene
100000
22
80
3 hours-40
E
Fuel Oil
7000
120
1200
4 hours-300
F
Fuel Oil
7000
70
1200
4 hours-800
F
Fuel Oil
4000
120
1200
2 hours-200
G
Fuel Oil
7000
70
1200
4 hours-750
H
Fuel Oil
7000
120
1200
4 hours-720
D
Raw Oil **
4000
70
2300
4 hours-1600
F
Raw Oil
4000
22
2300
4 hours-1950
*Catalytic solution contains 1% Cu 2+
**Oil with density of 0.80g/cm 3 with the output fraction 28-360° C. 88%, content of paraffin hydrocarbon 65%, naphten-26% was used.
[0037] Examples 7-8 show that it is not possible to keep the objects of the present invention if parameters of catalyst deviate from the parameters in accordance with the present invention.
EXAMPLE 7
[0038] Synthesis of the complex is performed as in Example 1 but instead acetonitryl, chloroform is utilized. During with the process of purification of kerosene in accordance with FIG. 2, the content of mercaptan sulfur is reduced to 60 ppm.
EXAMPLE 8
[0039] Synthesis of the complex is performed as in Example 1, but the reaction solution is not heated. When the purification is performed with Example 2, the content of mercaptide sulfur is reduced to 40 ppm.
[0040] 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 substances and methods differing from the type described above.
[0041] While the invention has been illustrated and described as embodied in catalyst and method for alkali-free purification of oil raw material from mercaptans, 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.
[0042] Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, be applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. | A catalyst for alkali-free purification of oil raw materials includes a solid metalocomplex or a liquid metalocomplex with a general formula (Cu M Cl)20(Li)2̂(L 2 )î, where Li is amino alcohol, L2 is acetonitryl or single atom alcohol. | 1 |
TECHNICAL FIELD
The present invention relates to a diesel particulate trap. More specifically, the present invention relates to a method and apparatus for regenerating a diesel particulate trap using microwave radiation.
BACKGROUND OF THE INVENTION
Increased regulation has reduced the allowable levels of particulates generated by diesel engines. The particulates can generally be characterized as a soot that is captured and reduced by particulate filters or traps. Present particulate filters or traps contain a separation medium with tiny pores that capture particles. As trapped material accumulates in the particulate trap, resistance to flow in the particulate trap increases, generating backpressure. The particulate trap must then be regenerated to burn off the particulates/soot in the particulate trap to eliminate the backpressure and allow air flow through the particulate trap. Past practices of regenerating a particulate trap utilized an energy source such as a burner or electric heater to generate combustion in the particulates. Particulate combustion in a diesel particulate trap by these past practices has been found to be difficult to control and may result in an excessive temperature rise.
SUMMARY OF THE INVENTION
The present invention is a method and apparatus for regenerating a particulate trap using microwave energy. The present invention in the preferred embodiment uses concentrated particulate matter ignited by microwave radiation to initiate the burn off of particles/soot in a particulate trap. The particulates are concentrated in desired areas in the particulate trap using structures such as tabs or walls.
The present invention includes a particulate trap placed in the exhaust flow of a diesel engine. A microwave source may be operatively coupled to a wave guide, and a focus ring may be used to direct the microwaves to particulate matter or microwave absorbing materials. The concentrated particulate matter or microwave-absorbing material generates heat in response to incident microwaves to burn off particulates. Materials transparent to microwaves are preferably used for the basic construction of the particulate trap housing and other areas in the particulate trap where it would be inefficient to absorb microwave energy. By strategically locating structures to accumulate particulate matter and/or microwave absorbing materials, microwaves may be used efficiently at the locations they are most needed to initiate the burn off of particulates and heat catalyst materials.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic drawing of a wall flow monolith particulate trap.
FIG. 2 is a diagrammatic drawing of the microwave regeneration system of the present invention.
FIG. 3 is a diagrammatic drawing illustrating a particulate trap of the present invention.
FIG. 4 is a plot detailing the exhaust gas velocity, flame front, and heat release generated by the end plug heating illustrated in FIG. 3 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a diagrammatic drawing of a typical wall flow monolith particulate trap 10 “particulate trap” used in diesel applications. The particulate trap 10 includes alternating closed cells/channels 14 and open cells/channels 12 . Exhaust gases such as those generated by a diesel engine enter the closed end channels 14 , depositing particulate matter 16 and exiting through the open channels 12 . The particulate trap 10 structure is preferably comprised of a porous ceramic honeycomb wall of chordierite material, but any ceramic honeycomb material is considered within the scope of the present invention.
FIG. 2 is a diagrammatic drawing of the microwave system 22 of the present invention. The system 22 includes a particulate trap 10 placed in the exhaust flow of a diesel engine. A microwave power source 26 and microwave antenna 28 may be operatively coupled to a wave guide 30 , and an optional focus ring 32 to direct the microwaves to the particulate trap 10 . In alternate embodiments of the present invention, the microwave antenna 28 is directly coupled to the housing of the particulate trap 10 .
Concentrated particulate deposits generate heat in response to incident microwaves to initiate the burn off of particulates in the particulate trap 10 . Materials such as chordierite that are transparent to microwaves are preferably used for the basic construction of the particulate trap 10 housing and other areas in the particulate trap 10 where it would be inefficient to absorb microwave energy. As the chordierite does not absorb microwave energy, the microwaves will “bounce” around until they are incident upon the particulate deposits. The temperature of the particulate trap 10 may be regulated by the timed build up of particulates and by controlling the application of the microwave energy. A metallic honeycomb 32 may be fitted to the particulate trap 10 to block microwaves exiting the particulate trap 10 .
FIG. 3 is a diagrammatic drawing of a particulate trap configured with structures 40 to collect particulate matter. The structures 40 will accumulate matter in preferred locations in the particulate trap 10 . Diesel exhaust filled with particulates flows through the particulate trap, depositing particulates 42 upon walls 44 of the particulate trap 10 with concentrations of particulate matter occurring around the structures 40 and end plug 46 . The microwave field density will inherently focus on the most microwave absorbent materials. In the present invention, the most absorbent materials in the particulate trap 10 are the particulate concentrations around the mid-channel structures 40 and the end plug 46 . The particulate concentrations create a hot spot or ignition point for the microwave energy that burns off particulates deposited on the walls 44 of the particulate trap 10 . Microwaves incident upon particulate deposits initiate the burn off of the particulates 42 to clear the walls 44 of the particulate trap 10 , as seen by waves 50 that represent the flame front of the particulate burn off. The ignition of a relatively small amount of particulates, that are ignited by the particulate concentrations, will be leveraged to burn a relatively large amount of particulates. The present invention is self regulating in temperature, as energy absorption by the deposits of particulate matter will stop as the particulates combust. Accordingly, the microwave energy will be absorbed by the next largest carbon deposit within the particulate filter. This pattern of microwave absorption and particulate combustion uniformly initiates the regeneration process within the particulate filter.
FIG. 4 illustrates the performance of the particulate trap shown in FIG. 3 . The exhaust gas velocity shown as plot 60 will decrease as a function of the distance of the closed end channel. The heat shown as plot 62 generated by the particulate heat release will initially be localized mid-channel and near the end plug 46 , and then propagate as a burn-off flame front shown by arrows 64 and 66 .
The preferred structures 40 used to generate the build up of particulate matter have been show as walls in the present invention, but any structure that may generate a concentration of particulate matter in a particulate trap is considered within the scope of the present invention. The structures include, but are not limited walls, tabs, points, arrays of prominences, and other similar structures.
It is to be understood that the invention is not limited to the exact construction illustrated and described above, but that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims. | A method and apparatus for initiating regeneration in a particulate trap including the steps of locating structures in the particulate trap in areas that generate particulate build up, generating microwaves, absorbing microwaves with the particulate build up, and controlling the microwaves to initiate a burn off of particulates. | 8 |
FIELD OF THE INVENTION
This invention relates to apparatus for fluorinating particulate matter, and more particularly, to a compressor for enhancing the reaction between fluorine gas and uranium pentafluoride particles.
BACKGROUND OF THE INVENTION
In copending application Ser. No. 168,877 filed July 14, 1980, entitled PHOTOCHEMICAL REACTION CAVITY by the same inventor as the present application and assigned to the same assignee, there is described an optical cavity for use in a process for enriching uranium by increasing the percentage of U 235 . Laser beams of two different frequencies are used to produce a photochemical reaction in which an atom of fluorine is stripped from a molecule of UF 6 , a gas, to precipitate out UF 5 which is a solid. The UF 5 powder, which has a higher concentration of U 235 isotopes, must then be refluorinated to produce UF 6 gas also having a higher concentration of U 235 isotopes. This basic enrichment process has been described in the literature. See, for example, the brochure, "Introduction to Laser Isotope Separation" published by the Los Alamos Scientific Laboratory, publication LASL-78-13 of the Applied Photochemistry Division.
SUMMARY OF THE INVENTION
The present invention is directed to an improved apparatus for refluorinating the uranium pentafluoride UF 5 powder after enrichment of U 235 isotopes to provide the more useful gas, uranium hexafluoride UF 6 . The refluoridation apparatus of the present invention includes a positive displacement type compressor with means directing a charge of a gaseous mixture containing a fluorine gas with suspended particles of uranium pentafluoride into the compressor at the start of a compression cycle. When the mixture is fully compressed, a source of fluorine gas under pressure is used to flush out the compressed gaseous mixture from the compressor cylinders including any uranium pentafluoride particles which have not been refluorinated during the compression.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the invention reference should be made to the accompanying drawings, wherein:
FIG. 1 is a top view of the apparatus of the present invention;
FIG. 2 is a sectional view taken substantially on the line 2--2 of FIG. 1;
FIG. 3 is a sectional view taken substantially on the line 3--3 of FIG. 2;
FIGS. 4-8 are a series of diagramatic views showing the compression cycle in the refluorination operation;
FIG. 9 is a detailed cross-sectional view of the cylinder and piston construction; and
FIG. 10 is a sectional view taken on the line 10--10 of FIG. 9.
DETAILED DESCRIPTION
Referring to FIGS. 1-3 in detail, the numeral 10 indicates generally a hopper which stores uranium pentafluoride UF 5 in powder form. The hopper is part of an entirely closed system in which the UF 5 is precipitated out of a gaseous stream of uranium hexafluoride UF 6 by a photochemical process such as described in the above-identified copending application. The UF 5 may be separated out from the gas stream by a cyclone separator, for example. The bottom of the hopper 10 is divided into four discharge passages indicated at 12, 14, 16 and 18, each of which is connected to a port in an associated one of four cylinders 20, 22, 24 and 26 of a compressor assembly 28.
The compressor assembly 28 is of generally conventional design for a four-cylinder, positive-displacement compressor. Thus the compressor assembly includes a block 30 in which the four cylinders are formed. Each cylinder receives a piston, as indicated at 32, 34, 36 and 38. The pistons are connected by suitable piston rods 40, 42, 44 and 46 to a crank shaft 48, the crank shaft being journaled in suitable bearing box 50. The crank shaft is driven by a motor 52 through a chain drive 54, rotation of the crank shaft 48 causing the pistons to reciprocate in the respective cylinders.
As best seen in FIG. 3, the passages 12-18 of the hopper 10 opens through ports 56 in the wall of the respective cylinders 20-26. The position of the port is such that the port is open and closed by the piston as it moves in the cylinder. The UF 5 powder from the hopper 10 is fluidized and injected into the respective cylinders by a gas stream from a first source 59 which is preferably gaseous fluorine or any suitable fluorine donor gas molecule or mix of gases mixed with an inert gas. The gas is inserted into the respective passages 12, 14, 16 and 18 through injection nozzles, such as indicated at 58 in FIG. 3. The injection of the gas stream is controlled by an associated valve 60, the valve being opened to coincide with the opening of the port 56 as the piston reaches the end of its stroke. Thus a mixture of fluorine donor gas and UF 5 powder in a measured charge is injected into the respective cylinders to be compressed by the reciprocal motion of the pistons.
When the mixture of fluorine and UF 5 is fully compressed, some of the fluorine atoms react with the uranium pentafluoride to form uranium hexafluoride UF 6 . The compressed mixture is flushed out of the associated cylinder by injecting additional fluorine donor gas under pressure from a second source 61 through a valve and heating element 62 into the end of the cylinder through a port 64. The fluorine flush gas stream and compressed mixture are flushed out of the cylinder through another port 66 in the end of the cylinder through a valve 68 into an outlet manifold 70. The manifold may be connected to a vacuum pump (not shown) which continuously exhausts the refluorinated material from the output of the compressor.
The four sets of valves 60, 62 and 68 may be opened and closed either mechanically or electrically in conventional manner so that the operation of the valves is timed with the rotation of the crank shaft 48. The timing sequence is shown by the diagram of FIGS. 4-8. As shown in FIG. 4, the piston 32 is at the compression end of the stroke in which the volume of the cylinder 20 is reduced to its minimum, for example, 10 cc. With the valve 68 open and the valve 62 closed, the pressure in the cylinder is reduced to the subatmospheric value of approximately 100 torr. In FIG. 5, with both the valves 62 and 68 closed, and the volume of the cylinder increased to 900 cc., the pressure drops to 1.1 torr. At the end of the stroke, as shown in FIG. 6, the port 56 is opened and the valve 60 is opened to inject a mixture of UF 5 and F 2 into the cylinder. The volume of the cylinder reaches its maximum of 1000 cc. and the pressure increased to 80 torr. As the piston 32 reaches the compression end of its stroke, as shown in FIG. 7, with both the valves 62 and 68 closed, the pressure builds up to 8000 torr as the volume decreases to 10 cc. At the compression end of the stroke, as shown in FIG. 8, both the valves 62 and 68 are opened allowing the compressed mixture to be flushed from the cylinder. The cycle is then repeated. The above pressure and volume values are given by way of example only.
In order to prevent buildup of UF 5 on the end of the cylinders, a rotating scraper is provided in each cylinder. As shown in FIGS. 9 and 10, the scraper is in the form of a disc 74 which has a flat outer surface 76 and a back surface which is contoured to fit the end of the cylinder, as indicated at 78. The disc 74 is secured to the end of a shaft 80 which is journaled in a sleeve 82 in the compressor block. Thus the scraper can rotate or move axially within the cylinder. A spring 84 normally urges the scraper towards the head of the piston, the spring extending between a bracket 86, mounted on the outside of the block and having a hole through which the shaft 80 projects, and a retainer 88 secured to the shaft 80. The retainer 88 acts as a stop, limiting motion of the scraper axially into the cylinder. As shown in FIG. 10, the flat face 76 of the scraper has a plurality of scraper fingers 90 which project toward the top of the associated piston. The fingers are so positioned that as the scraper is rotated, the fingers move in circular paths across the surface of the piston to scavenge any UF 5 particles that tend to accumulate. The shaft may be rotated in any suitable manner such as by motor 92 and chain drive 94, as shown in FIG. 2. At the end of the stroke, the face of the piston 32 comes into contact with the ends of the scraper fingers 90, compressing the spring 84 slightly. While in contact with the piston, the fingers 90 are rotated so as to scour the surface of the piston. The piston may also be provided with rings 94 which scavenge the walls of the cylinder to prevent any buildup of UF 5 particles. The walls of the cylinders also may be heated by an external heater system 96 to a temperature which tends to vaporize the UF 5 particles. The external heater system 96 is not to be restricted to any particular method, but may, for example, be a thermal trace wire.
From the above description it will be seen that an apparatus is provided which provides optimum conditions of pressure and temperature to enhance mixing, intermolecular collision and reaction to cause the UF 5 and F 2 to combine to produce UF 6 . While fluorine gas has been described as the preferred embodiment, other sources of fluorine atoms may be used.
The apparatus provides for substantially continuous operation because of the overlapping compression cycles of the four cylinders. The self-cleaning action ensures operation with a minimum of down time to service and clean out the cylinder chambers of the compressor.
It is to be understood that what has been described is merely illustrative of the principles of the invention and that numerous arrangements in accordance with this invention may be devised by one skilled in the art without departing from the spirit and scope thereof. | A positive-displacement compressor receives a gaseous mixture of fluorine and uranium pentafluoride particles. The mixture is compressed by the compressor to cause the fluorine in the gas to react with the uranium pentafluoride to form uranium hexafluoride. The compressed mixture in the compressor is removed by a stream of warm fluorine gas to scavenge the excess particulate matter from the compressor and enhance the refluoridation process. | 1 |
RELATED APPLICATION
This application claims the benefit of EP 04 005 460.3, filed on Mar. 8, 2004, the contents of which are incorporated herein.
FIELD OF THE INVENTION
This invention is related generally to the field of web handling machinery. More particularly, the invention relates to the control of the speed of web material in web handling machinery in situations in which the relative speeds of different portions of the web fluctuate with respect to each other.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,590,442 describes web storage apparatus for non-woven fabrics. The web storage apparatus is located between a web producer and web processing apparatus, e.g., between a carding machine, operating at constant output speed, and fabric laying apparatus, operating at rhythmically variable take-up speeds. In such fabric laying apparatus, the transport speed of the web within the machine changes during transport depending on the movements of the laying carriage within the fabric laying apparatus. The web storage apparatus is controlled in accordance with the transport speed of the laying belts of the fabric laying apparatus, such transport speed fluctuating with the rhythm of the absolute traveling speed of the laying carriage.
This known web storage apparatus consists of a U-shaped section of variable length of an endless belt conveyor extending between the web producer and the fabric laying apparatus. The web storage apparatus supplies the web output from the web producer, which produces web material at a substantially constant speed, to the fabric laying apparatus, which requires web material to be supplied to it at a fluctuating speed. The length of the U-shaped section (and thereby the length of the path that web material must travel) is varied by displacing a frame which holds a pair of deflecting rollers. A carriage-mounted endless support belt aligns with the conveyor belt in its U-shaped section, and in this section, the support belt tightly contacts the conveyor belt, thereby clamping the web material between these two belts. The web storage apparatus is therefore capable of controlling the regular web supply speed of the web producer in accordance with the variable take-up speed of the web processing apparatus.
In order to accomplish the changes in the path length, also known as web buffering, the movements of the frame and the carriage must be matched with one another, which requires special effort, since a sufficient tension of the conveyor belt must always be ensured to maintain the clamping effect between the conveyor belt and the support belt in order to prevent any damage of the sensitive, unsolidified web material in the web storage apparatus. Such coordinated control is both complex and costly. Further, along some portions of the web path from the infeed from the web producer to the outfeed to the web processing apparatus, the web material is not fully clamped, leaving the web material susceptible to disturbances from drafts. Thus there is a need for web buffering apparatus which can provide the web speed-matching function between various pieces of equipment in less costly, less complex manner and provide protection for the web while maintaining a high quality level in the web material.
OBJECTS OF THE INVENTION
It is an object of the invention to provide improved web buffering apparatus which overcomes some of the problems and shortcomings of the prior art, including those referred to above.
Another object of the invention is to provide web buffering apparatus which is easily controlled.
Another object of the invention is to provide web buffering apparatus which interfaces more easily with certain web processing apparatus.
Still another object of the invention is to provide web buffering apparatus which protects the web material along its path through the buffering apparatus.
Yet another object if the invention is to provide web buffering apparatus which is structurally simple.
How these and other objects are accomplished will become apparent from the following descriptions and the drawings.
SUMMARY OF THE INVENTION
The apparatus of this invention takes up a web material supplied at a take-up speed and outputs this material at a discharge speed which fluctuates with respect to take-up speed but on average matches take-up speed. The inventive apparatus includes two endless transport belts which together define a take-up site for receiving the web material therebetween and which further include a discharge site for outputting the web material. The transport belts are guided in juxtaposition between the take-up site and the discharge site to clamp the web material between the belts. Each transport belt includes and feed section and a return section. Each feed section is of varying length and has a substantially U-shaped feed path portion. The belts in such feed sections together are guided over a first deflecting roller substantially half-wrapped by the belts. Each return section is also varying length, and the belts in such return sections are separately guided from the discharge site to the take-up site and each runs through a substantially U-shaped return path portion extending opposite to the U-shaped feed path portion and substantially half-wrapping one of second and third deflecting rollers, respectively. The apparatus also includes a common mounting frame rotatably supporting the three deflecting rollers and movable on a machine stand, and the common mounting frame moves substantially parallel to the U-shaped path portions. For each belt, the apparatus enables the length of the feed section to vary with respect to the length of the return section.
In preferred embodiments of the inventive apparatus, the common mounting frame is movably held by a pendulum.
In a preferred embodiment of the apparatus, the common mounting frame is pivotably supported around the axis of the first deflecting roller. Such embodiments may also further include a tensioning roller about which the belt from one of the U-shaped return path portions is substantially half-wrapped. The tensioning roller is biased away from the U-shape of such return path portion.
In other preferred embodiments, the apparatus further includes first and second independent drive rollers and a common drive roller. The transport belts are each guided over one of the independent drive rollers, and their feed sections are commonly guided over the common drive roller, the common drive roller being driven at a circumferential speed that is variable with respect to the circumferential speeds of the first and second independent drive rollers. In such apparatus, the discharge speed is thus varied with respect to the take-up speed.
Another preferred embodiment of the inventive apparatus also includes first and second independent drive rollers. The transport belts are each guided over one of the independent drive rollers, and the first deflecting roller is also a drive roller driven at a circumferential speed that is variable with respect to the circumferential speeds of the first and second independent drive rollers, whereby the discharge speed of the apparatus is varied with respect to the take-up speed of the apparatus.
In a highly-preferred embodiment, the apparatus is connected to a camel back cross lapper which includes an endless output conveyor and a series of at least two arms, adjacent pairs of which are pivotably connected at common ends. The series of arms includes a supply arm and a laying arm. The supply arm is pivotably mounted on the machine stand. The layering arm has a layering-arm upper end hinged to the upper end of the adjacent arm and extending therefrom downward to a laying-arm lower end above the output conveyor. The layering-arm lower end is movable transversely with respect to the output conveyor and has two discharge rollers which form a discharge site for the web material. In such apparatus, the transport belts are guided in pairs along the series of arms to the laying-arm lower end, guided separately over the discharge rollers, and separately returned along the arms to the take-up site. In some embodiments, the series of arms consists only of the supply arm and the laying arm.
Another embodiment of the inventive apparatus further includes two return drive rollers and each of the return sections between the supply arm and the U-shaped return path portions wrap at least 90° around a respective one of the return drive rollers.
In other preferred embodiments, each arm of the inventive apparatus has guide rollers alternatingly contacting opposite sides of the juxtaposed feed sections of the transport belts. The apparatus also may include two return drive rollers, each of the return sections between the supply arm and the U-shaped return path portions wrapping at least 90° around a respective one of the return drive rollers.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows apparatus according to the invention in integral combination with a camel back cross lapper with the laying arm in a retracted position
FIG. 2 shows the apparatus of FIG. 1 with the laying arm in an extended position.
The drawings only show the essential features of the invention, and this in schematic view only, since a schematic view is sufficient for the understanding the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows a first arm 2 , also designated as a supply arm, and a second arm 3 , also designated as a laying arm, of a camel back cross lapper 1 for fleece production. Supply arm 2 is pivotally supported at its lower end 2 L in a machine stand M (shown in dotted line format on FIG. 1 ). A hinge H at the upper end 2 U of the supply arm 2 and the upper end 3 U of laying arm 3 provides hinging movement between arms 2 and 3 . The lower end 3 L of arm laying 3 is capable of being transversely moved above an output conveyor 60 by means of a stationary drive 4 and a toothed belt 5 , with a deflecting roller 6 of output conveyor 60 being schematically shown in the drawing. (The apparatus shown in FIGS. 1 and 2 contain numerous deflecting and drive rollers which will be specified primarily by reference number only and not by differentiating names.) Output conveyor 60 extends perpendicularly to the direction of movement of lower end 3 L of laying arm 3 and around deflecting roller 6 . A cover belt 7 is connected to lower end 3 L of laying arm 3 . Cover belt 7 is guided over several deflecting rollers 8 on both sides of output conveyor 60 and extends over output conveyor 60 to keep air turbulence away from the laid fleece, the turbulence being caused by the movement of laying arm 3 at a discharge site B at lower end 3 L of laying arm 3 . Cover belt 7 also serves to avoid formation of folds in the fleece being produced.
FIGS. 1 and 2 show a variable-volume web buffering apparatus 9 to the left of camel back cross lapper 1 . Web buffering apparatus 9 comprises two transport belts 10 and 11 , each of which runs through web buffering apparatus 9 and which is also guided over arms 2 and 3 of camel back cross lapper 1 up to the discharge site B.
Transport belts 10 and 11 together determine a take-up site A at which fiber web material (not shown) coming from a web generating means (also not shown) and to be layered by cross lapper 1 is supplied into a gap between transport belts 10 and 11 . Starting out from take-up site A, transport belts 10 and 11 extend as a pair over a deflecting roller 12 , a drive roller 13 , a deflecting roller 14 and over arms 2 and 3 of camel back cross lapper 1 , wherein belts 10 and 11 are guided at hinge H connecting arms 2 and 3 over a deflecting roller 15 . From there, belts 10 and 11 run to two additional deflecting rollers 16 and 17 at lower end 3 L of laying arm 3 , at which point belts 10 and 11 are separated from one another at discharge site B, to be guided back independently from one another via arms 3 and 2 of cross lapper 1 to take-up site A. Deflecting rollers 16 and 17 together determine discharge site B at which the web supplied by cross lapper 1 is deposited by laying arm 3 onto output conveyor 60 by reciprocating pivotal movements of arms 2 and 3 .
As transport belt 10 returns from discharge site B to take-up site A, transport belt 10 runs over a deflecting roller 18 arranged in hinge H of arms 2 and 3 . After belt 10 leaves supply arm 2 , it runs over a deflecting roller 19 and a drive roller 20 . From this point, it runs in a substantially U-shaped path section, the apex of which is formed by a deflecting roller 21 , to a deflecting roller 22 and a drive roller 23 at take-up site A.
Transport belt 11 runs over a deflecting roller 24 located at hinge H of the two arms 2 and 3 , and after leaving supply arm 2 , belt 11 runs over a deflecting roller 25 , a drive roller 26 , and a U-shaped path section in whose apex a deflecting roller 27 is located, to a deflecting tension roller 28 and a drive roller 29 located at take-up site A.
The deflecting rollers 21 and 27 located in the apexes of the U-shaped path sections of returning transport belts 10 and 11 , respectively, are rotatably supported on a common mounting frame 30 in which deflecting roller 12 is also supported. The paired feed sections of the transport belts 10 and 11 thus run around deflecting roller 12 . Frame 30 is pivotally supported in the axis of deflecting roller 12 on a frame-like swinging link 31 , which is shown in the drawing only schematically with a dash-dotted line and which is suspended like a pendulum in a pivot bearing 32 in machine stand M.
Deflecting tension roller 28 is attached at a piston arm 33 A of a hydraulic cylinder 33 . A tie force exerted by hydraulic cylinder 33 onto deflecting tension roller 28 provides tension to transport belt 11 . The tie force is transferred via deflecting roller 27 and frame 30 , which acts as a two-armed lever and which pivots around the axis of deflecting roller 12 that transport belts 10 and 11 have in common, and via deflecting roller 21 onto the return section of transport belt 10 . Thus, transport belts 10 and 11 can both be tensioned by a single hydraulic cylinder 33 .
On the paths over arms 2 and 3 , transport belts 10 and 11 run over several guide rollers 34 supported on arms 2 and 3 , some of guide rollers 34 alternatingly contacting both sides of the transport belt sections guided in pairs to prevent flapping of transport belts 10 and 11 along arms 2 and 3 .
As long as drive rollers 13 , 20 , 23 , 26 and 29 have identical circumferential speeds, frame 30 rests in the state shown in FIG. 1 . When the circumferential speed of drive roller 13 becomes larger than the circumferential speed of the other drive rollers, drive roller 13 draws frame 30 to the left in FIG. 1 , through paired transport belts 10 and 11 and deflecting roller 12 , decreasing the lengths of the web material feed sections of transport belts 10 and 11 . Link 31 supporting frame 30 is thus swung to the left. At the same time, the lengths of the returning sections of transport belts 10 and 11 are increased, since deflecting rollers 21 and 27 , supported on frame 30 and deflecting the return sections of the transport belts in a U-shaped manner, are also moved to the left. Positions of deflecting rollers 12 , 21 and 27 moved to the left are indicated in the drawing with 12 ′, 21 ′ and 27 ′, respectively. If, however, the drive speed of drive roller 13 becomes smaller with respect to the drive speeds of the other drive rollers, frame 30 moves to the right in FIG. 1 so that deflecting rollers 12 , 21 and 27 reach the positions shown in dotted lines by 12 ″, 21 ″ and 27 ″, respectively. Link 31 supporting frame 30 is thereby swung to the right. Since the adjustment of deflecting rollers 12 , 21 and 27 takes place in essentially equal amounts, transport belts 10 and 11 remain tensioned.
By the aid of the movement of frame 30 along with link 31 , the length of transport belts 10 and 11 between take-up site A and discharge site B can be varied. Thus, it is possible to temporarily change the speed of the web discharge at discharge site B with respect to the web take-up speed at take-up site A. This change is required for cross lapper 1 , since the speed at which discharge site B, i.e., lower end 3 L of laying arm 3 , moves over output conveyor 60 , cannot be constant, since in the area of the movement reversal points of arm 3 , its speed must be reduced by braking to zero and then accelerated in the opposite direction after the reversal of the movement. If during these braking and acceleration phases arm 3 continued to discharge the web material at the constant speed of transport belts 10 and 11 , web upsetting and web thickening would result in marginal portions of the fleece web laid by cross lapper 1 , and such variations must be prevented. Thus it is necessary to vary the speed at which the web material is discharged from transport belts 10 and 11 , adapting to the speed of laying arm 3 at which this arm moves across output conveyor 60 . This variation of the discharge speed of the web material from the gap between deflecting rollers 16 and 17 at discharge site B can be managed by suitable control of the speed of drive rollers 13 , 20 and 26 with respect to the speed of drive rollers 23 and 29 , wherein frame 30 carries out a substantially swinging movement around pivot bearing 32 . This swinging movement moves deflecting rollers 12 , 21 and 27 between positions 12 ′, 21 ′ and 27 ′ on the one hand and positions 12 ″, 21 ″ and 27 ″ on the other hand, respectively, and thereby cyclically varies the web volume buffered in the web buffering apparatus.
In a synopsis of FIGS. 1 and 2 , a further movement component of frame 30 is now explained. FIG. 2 shows cross lapper 1 in an extended position of supply arm 2 and laying arm 3 . It can readily be seen in FIG. 2 that the wrapping angles of transport belts 10 and 11 on deflecting rollers 15 , 18 and 24 , which are arranged at hinge H of arms 2 and 3 , and at deflecting rollers 14 , 19 and 25 , which are arranged in the area of a fixed bearing point F of supply arm 2 , vary from the wrapping angles shown in FIG. 1 . While the change of the wrapping angles of the paired transport belt sections and also the change of the wrapping angles at deflecting rollers 18 and 24 located at hinge H of the arms 2 and 3 do not have opposite influences on transport belts 10 and 11 as far as the return sections thereof are concerned, the wrapping angle of the returning section of transport belt 10 at deflecting roller 19 in FIG. 2 is smaller compared to the position shown in FIG. 1 . However, the wrapping angle of the returning section of the other transport belt (belt 11 ) at deflecting roller 25 is larger than in the position shown in FIG. 1 . Such wrapping angles of transport belts 10 and 11 therefore change in opposite directions. Transport belt 10 requires an increase in the running path length of its returning section, while transport belt 11 requires a decrease in the running path length of its returning section. Both can be achieved by the aid of tension roller 28 , which is influenced by hydraulic cylinder 33 , which, as shown in FIG. 2 , draws tension roller 28 to the right, resulting in frame 30 being pivoted on swinging link 31 counter-clockwise from its position shown in FIG. 1 into the position shown in FIG. 2 . The length of the returning section of transport belt 11 is decreased, and at the same time, the length of the returning section of transport belt 10 is increased.
It is obvious that the swinging movements of frame 30 around pivot bearing 32 of pivotal link 31 and the pivoting movements of frame 30 at swinging link 31 around the axis of deflecting roller 12 deflecting paired transport belts 10 and 11 combine in operation, since the compensation of the speed difference of transport belts 10 and 11 at discharge site B and take-up site A and the compensation of the change in the opposite direction of roller wrapping angles must take place simultaneously.
As an example, the laying width on output conveyor 60 can be 3,500 mm. The length of arms 2 and 3 between deflecting roller 24 and the ends of the arms is approximately 2,800 mm each. Transport belts 10 and 11 each have a length of 21,500 mm. The maximum movement path of camel back cross lapper 1 is 4,000 mm. In the retracted state of arms 2 and 3 , as shown in FIG. 1 , arms 2 and 3 include an angle of approximately 27°, whereas in the extended position shown in FIG. 2 , arms 2 and 3 include an angle of approximately 133°. The difference in the yielding of transport belts 10 and 11 caused by the change of the wrapping angle at deflecting rollers 19 and 25 (in turn caused by the different arm positions during extension, i.e. when the angle included between arms 2 and 3 is enlarged), is compensated by an adjustment of approximately 200 mm on tension roller 28 by means of hydraulic cylinder 33 . Frame-shaped swinging link 31 , at which frame 30 is pivotally suspended, has an effective length (pendulum length) of 1,400 mm, whereas the distance of deflecting rollers 21 and 27 at frame 30 from deflecting roller 12 common to transport belts 10 and 11 is 520 mm each. For accommodating web buffering apparatus 9 , a space of approximately 2,100 mm in front of camel back cross lapper 1 and of a height of approximately 1,750 mm is required, including swinging link arrangement 31 .
A variety of alternatives are possible and are obvious to a person skilled in the art of the present invention. Common deflecting roller 12 supported in frame 30 could be, for instance, a drive roller, with roller 13 serving as an idling deflecting roller. Furthermore, deflecting rollers 21 and 27 supported on frame 30 may be drive rollers, with rollers 20 and 26 serving as idling deflecting rollers. Frame 30 , instead of being suspended on swinging link 31 , could be pivotally supported in a carriage movable on rails. Furthermore, cross lapper 1 could have four pivotably-connected arms for achieving a larger laying width, such arms being arranged and movable in accordion-like fashion to avoid an increase of the height of cross lapper 1 . Transport belts 10 and 11 would then be guided in pairs over all four arms so that the web is held along its entire path by tightly contacting transport belts.
While the principles of the invention have been shown and described in connection with specific embodiments, it is to be understood that such embodiments are by way of example and are not limiting. | Apparatus for variably buffering a web material, the apparatus having two endless transport belts including feed sections in which the belts are juxtaposed, and return sections, the feed and return sections being of varying lengths. In the feed sections, the belts move through a U-shaped path portion, commonly guided over a deflecting roller. In the return sections, the belts are guided through U-shaped path portions extending opposite to the U-shaped path portion of the feed sections, each belt wrapping separate deflecting rollers. The three deflecting rollers are rotatably supported on a common mounting frame movably held in a machine stand for compensated length variation of the feed and return portions. | 3 |
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a sanitary ware, and more particularly to a sanitary ware with an annular mount.
2. Description of the Related Art
Sanitary wares are commonly used in restrooms and bathrooms, may be but are not limited to shower heads, nozzles or hoses and each has a body. A sanitary ware is fixed to or removably mounted on a wall or ceiling. However, the sanitary ware is generally mounted in a clamp corresponding to the body so when replaced, corresponding clamps also require replacement complicating do-it-yourself replacement.
Thus, a need exists for a sanitary ware with an annular mount for providing a convenient way for use.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide sanitary ware with an annular mount.
Sanitary ware with an annular mount has a body, an inlet pipe and an annular mount. The inlet pipe is mounted inside the body. The annular mount is mounted through the body for hanging the sanitary ware. A structure of the annular mount is simple to prevent leaking and could be used in any sanitary ware. Therefore, the sanitary ware with the annular mount can be hung anywhere by the annular mount.
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
FIG. 1 is a perspective view of a sanitary ware with an annular mount in accordance with the present invention;
FIG. 2 is an exploded perspective view of the sanitary ware with the annular mount in FIG. 1 ;
FIG. 3A is a side view in partial section of the sanitary ware with the annular mount in FIG. 1 ;
FIG. 3B is an enlarged side view in partial section of the sanitary ware with the annular mount in FIG. 1 ; and
FIG. 4 is a perspective view of showing an operational embodiment of the sanitary ware with the annular mount in FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
As defined herein sanitary ware refers to shower heads, hoses, faucets, nozzles and the like.
With reference to FIGS. 1 to 3 , sanitary ware ( 10 ) with an annular mount in accordance with the present invention has a body ( 11 ), an inlet pipe ( 13 ) and an annular mount ( 20 ).
The body ( 11 ) may be any conventional sanitary device, such as shower head, pipe or faucet, and has a front, a rear a cavity, a top, a bottom, at least one output ( 111 ), a partition ( 12 ), a hose mount ( 14 ) and a through hole ( 15 ) and may be formed in the body ( 11 ). The cavity is defined inside the body ( 11 ).
In a preferred embodiment, the body ( 11 ) is rectangular and each output ( 111 ) is separately defined through the front of the body, maybe in the front.
The hose mount ( 14 ) is defined in the bottom of the body ( 11 ), communicates with the cavity and may be defined by the front and the rear and may be threaded. The through hole ( 15 ) is transversely defined through the body ( 11 ), is located below the output ( 111 ) and has a front edge, a rear edge, a rear shoulder ( 151 ), a front shoulder ( 152 ) and a gap ( 153 ). The front edge is disposed in the front of the body. The rear edge is located in the rear of the body. The rear shoulder ( 151 ) is annular, protrudes transversely from the rear edge of the through hole ( 15 ). The front shoulder ( 152 ) is annular, protrudes transversely from the front edge of the through hole ( 15 ) and has a free end, an inclined surface ( 1521 ) and a stop rib ( 1522 ). An inner diameter of the front shoulder ( 152 ) is smaller than an inner diameter of the rear shoulder ( 151 ). A ratio of diameters of the front to rear shoulders ( 151 , 152 ) may be between 1:1 to 1:1.03. The inclined surface ( 1521 ) is defined at the free end of the front shoulder ( 152 ). The stop rib ( 1522 ) is formed around the front shoulder ( 152 ) near the front edge. The gap ( 153 ) is formed between the rear shoulder ( 151 ) and the front shoulder ( 152 ) and communicates with the cavity in the body ( 11 ). The partition ( 12 ) is formed inside the cavity below the through hole ( 15 ) to prevent water flowing down the cavity and has a passing hole ( 121 ) defined in the partition ( 12 ) and the passing hole ( 121 ) communicates with the cavity in the body.
The inlet pipe ( 13 ) is mounted in the cavity in the body ( 11 ) and in the partition ( 12 ) and has a proximal end. The proximal end is mounted in the hose mount ( 14 ) and may engage the threads of the hose mount ( 14 ) and has a joint ( 131 ). The joint ( 131 ) is formed on the proximal end for connecting to a hose.
The annular mount ( 20 ) is mounted inside the through hole ( 15 ) in the body ( 11 ) and has a base ring ( 22 ), two O-rings ( 23 , 24 ) and a sleeve ( 25 ). The base ring ( 22 ) is mounted in the through hole ( 15 ) and has an abutting end, a rear end, a front end ( 222 ), a rear end ( 221 ) and a through hole ( 223 ). The front end ( 222 ) is integrally formed with the rear end ( 221 ). The front end ( 222 ) is receiving inside the through hole ( 15 ) mounted adjacent to the front shoulder ( 152 ) and abuts the stop rib ( 1522 ) and has an outer diameter. The rear end ( 221 ) is receiving inside the through hole ( 15 ) mounted adjacent to the rear shoulder ( 151 ) and has an outer diameter. The outer diameter of the front end ( 222 ) is slightly larger than the outer diameter of the rear end ( 221 ). A ratio of the outer diameter of the front end to the outer diameter of the rear end of the base ring ( 22 ) is about 1:1 to 1:1.03. The through hole ( 223 ) is defined through the base ring ( 22 ). The O-rings ( 23 , 24 ) are mounted around the base ring ( 22 ) respectively at the ends of the base ring ( 22 ).
The sleeve ( 25 ) may be made of rubber, is mounted through the base ring ( 22 ) and has a sleeve body ( 251 ) and two lips ( 252 ). The sleeve body ( 251 ) has two ends. The lips ( 252 ) are formed respectively around the ends of the sleeve body ( 251 ).
Because the inlet pipe ( 13 ) is mounted inside the body ( 11 ) and hot water does not touch the body ( 11 ) below the partition ( 12 ), the hot water scald a user holding the body.
With reference to FIG. 4 , the sanitary ware ( 10 ) with the annular mount may be hung on a hook (A) using the annular mount ( 20 ). The hook (A) is a circular hook mounted on a shower stand and has an enlarged free end. The annular mount ( 20 ) of the present invention is hung on the hook (A) by passing through the enlarged free end. Since the annular mount ( 20 ) is formed by the base ring ( 22 ) and the sleeve ( 25 ), water will not leak from the annular mount ( 20 ).
The advantages of the sanitary ware ( 10 ) are as follows.
1. The structure of the annular mount described in the present invention is simple and is easily fabricated.
2. The annular mount may be used in any kind sanitary ware for hang the sanitary ware.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. | A sanitary ware with an annular mount has a body, an inlet pipe and an annular mount. The inlet pipe is mounted inside the body. The annular mount is mounted through the body for hanging the sanitary ware. A structure of the annular mount is simple to prevent leaking and could be used in any sanitary ware. Therefore, the sanitary ware with annular mount can be hung anywhere by the annular mount. | 4 |
BACKGROUND OF THE INVENTION
The present invention relates to an amphibious vehicle.
The amphibious vehicle contemplated by the present invention is lightweight in nature. Nevertheless, it requires a power plant with a certain amount of power output in order that the vehicle on water can get up on to the plane and travel as a planing vehicle. Such power levels may however be capable of imparting undesirably high speed and acceleration potential to the vehicle when used on land. Moreover, legislative requirements in certain parts of the world actually restrict power and/or road speed for certain types of vehicles. For example, a Low Speed Vehicle in the USA must not be capable of exceeding 25 mph on the road while in Europe a road legal All Terrain Vehicle must be restricted to an engine power output of less than 15 kW/20 brake horsepower.
SUMMARY OF THE INVENTION
In a first aspect the present invention provides an amphibious vehicle comprising at least three wheels; handlebars operable to steer at least a front pair of the wheels; a sit-astride seat; a power plant driving at least one of the wheels when the vehicle is operating in a land mode; a jet drive or propeller driven by the power-plant when the vehicle is operating in a water mode; wherein power control means is provided to control in amount power delivered to drive the driven wheel(s), the power control means operating to limit power transmitted to the driven wheel(s) in land mode operation while allowing greater power to be transmitted to the jet drive or propeller.
In a second aspect the present invention provides an amphibious vehicle comprising: at least three wheels; handlebars operable to steer at least a front pair of the wheels; a sit-astride seat; a power plant driving at least one of the wheels when the vehicle is operating in a land mode; a jet drive or propeller driven by the power plant when the vehicle is operating in a water mode; wherein speed control means is provided to offer resistance to motion of the vehicle on land whilst not limiting speed of the vehicle over water.
In third aspect the present invention provides an amphibious vehicle comprising: at least three wheels; handlebars operable to steer at least a front pair of the wheels; a sit-astride seat; a power plant driving at least one of the wheels when the vehicle is operating in a land mode; a jet drive or propeller driven by the power plant when the vehicle is operating in a water mode; wherein the power plant outputs power via a rotating output shaft; and speed control means is provided to limit the rotational speed of the driven wheel(s) when the vehicle is operating in the land mode.
These and other features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments which, taken in conjunction with the accompanying drawings, illustrate by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an amphibious vehicle according to the present invention;
FIG. 2 is a view of the vehicle of FIG. 1 in which the top surface of the vehicle has been made transparent; and
FIG. 3 corresponds to the view in FIG. 2 , save that the FIG. 2 shows the vehicle in water mode and the FIG. 3 shows the vehicle in land mode.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning firstly to FIG. 1 there can be seen in the Figure an amphibious vehicle 10 having four wheels 11 , 12 , 13 and 14 , handlebars 15 for steering the front wheels 11 and 14 and a sit-astride seat 16 . As can be seen in FIG. 2 , there is located inside the vehicle a gasoline reciprocating piston multi-cylinder internal combustion engine 17 which when the vehicle is in land mode drives the two rear wheels 13 and 12 to rotate. The vehicle also has a jet drive 18 at the rear of the vehicle which is driven by the engine 17 to propel the vehicle 10 when operating in water mode.
The hull 19 of the vehicle has on its lower surface a planing surface (not shown) to enable the vehicle to plane across the water when in its water mode. To facilitate this the road wheels 11 , 12 , 13 and 14 are connected to the remainder of the vehicle by a suspension system which allows them to be moved between an extended position (as shown in FIG. 3 ) for land use and a retracted position (as shown in FIGS. 1 and 2 ) for use on water.
In order that the vehicle 10 operates as a planing vehicle on water, even when transporting 2 or 3 passengers, the engine 17 must have a certain power output. However, since the vehicle 10 will be very light, this power output if fully available on land would make the vehicle difficult to drive because it would be capable on land of excessive speed and excessive acceleration.
The present invention provides for the restriction of the power available to the road wheels and/or restriction of the speed of rotation of the road wheels by a power or speed control system which limits the power available to drive the wheels in road use or the rotational speed of the wheels, whilst allowing greater power to be available to the jet drive or propeller in marine use and/or allowing the jet drive/propeller to rotate at greater rotational speed than the road wheels. The power control system can take many forms, including:
1. Provision of a fuelling system for the engine 17 which operates to restrict the flow of fuel to the engine when the vehicle is operating in road mode. For an engine with a carburetor this would be done by metering the fuel supplied from a fuel pump and for a fuel injection engine the fuel supply pressure could be varied. For a diesel engine the mechanical governor could be restricted in land mode.
2. Provision of an exhaust throttle or brake which restricts flow of combusted gases from the combustion chambers of the engine 17 during road mode operation.
3. The use of an intake throttle whose limit of opening can be controlled so that in marine mode the intake throttle will be capable of opening to wide open throttle, but in land mode the movement of the throttle will be restricted to an extreme position which is still partly closed. This can be done by deploying a mechanical throttle stop to limit throttle movement in land mode and retracting the stop for marine use. Alternatively the throttle could be an electrically operated throttle controlled by an electronic control system which receives a signal indicative of position of a manually operable throttle control and controls position of the throttle accordingly; in land mode operation the system will limit throttle motion to restrict engine output power and thereby vehicle speed. A mechanical throttle damper could also be employed operable only in land mode to damp throttle movement (or with different characteristics in land and marine modes, with a greater degree of damping applied in land mode).
4. If the engine 17 is a multi-cylinder engine then it is envisaged that the engine could be provided with a cylinder deactivation system so that all of the cylinders would be active when the vehicle is operating in water mode and then some of the cylinders deactivated for land mode. If the engine is a spark ignition engine which uses port fuel injectors, one for each cylinder, then this could be achieved by deactivating the ignition system for the relevant cylinders and deactivating the port fuel injectors for the relevant cylinders.
5. The engine 17 could be provided with an electronic ignition system (assuming it is a spark ignition engine), and the timing of the spark could be varied to alter the power output of the engine between marine mode operation and land mode operation.
6. The engine 17 could be connected to the wheels 12 via a gearbox which is deliberately chosen to be a low ratio gear box so that the rotational speed of the wheels 12 and 13 is limited by the maximum speed of revolution of the engine 17 . The transmission could comprise a simple manual gearbox, an automatic gearbox or a continuously variable gearbox, all suitably configured to ensure that a gear ratio is never employed which at maximum engine speed would result in excessive land speed of the vehicle.
7. The engine 17 could be adapted to be a “dual fuel” engine, for instance operating using gasoline on water and using compressed natural gas (which has a lower calorific value) in land mode.
8. The engine 17 could be a supercharged engine with an engine driven compressor. The supercharger could be driven by a clutch and the clutch closed during marine mode (so that the engine is supercharged) and opened during land mode so that the engine loses its supercharging and therefore loses power.
9. The engine 17 could be a turbocharged engine. If so, a bypass passage could be included to bypass the turbocharger so that the engine is turbocharged only during marine operation and not during land use. Additionally, or alternatively the vanes in the turbocharger could be made to have a variable pitch, in which case the pitch would be varied to decrease boost in land mode and increase boost in marine mode. Additionally, or alternatively the engine could be provided with a pair of turbochargers, high pressure and low pressure, and the low pressure turbocharger used on its own in land mode could then be replaced by the high pressure turbocharger in water mode (or both turbochargers operated simultaneously in water mode).
10. The engine 17 could be provided with multiple poppet valves per cylinder, including at least two inlet poppet valves per cylinder. A poppet valve deactivation system could then be operated to deactivate e.g. one or each pair of inlet poppet valves, in order to decrease the flow of air through the engine in land mode.
11. The air inlet manifold for the engine 17 could be made of variable length and could be “tuned” to give good performance during marine mode operation (by ensuring that a standing wave is set up in the inlet manifold which gives rise to high pressure just behind the inlet poppet valves). The inlet manifold could then be “detuned” for land use to reduce the engine performance and output.
12. By suitable programming of an engine control unit it will be possible to give an engine characteristics for water mode operation which are different to the characteristics for land mode operation. For instance, the engine control unit can vary the fuelling (as described above) and the spark ignition timing (also described above). The engine control unit could be provide with a pair of different throttle maps, one for land use and the other for marine use.
13. Certain internal combustion engines have been proposed which achieve variable compression ratios in the cylinders of the engine. SAAB has an engine with a tilting cylinder block which enables compression ratio to be varied. Others have proposed variable length pistons or movable cylinder heads. Crank mechanisms have also been proposed in the past which vary the piston travel. Any of these mechanisms could be used to alter the power output from the engine so that the power output is greater in marine mode than in land mode.
14. It is known in several engines available today to vary in timing the opening and closing of inlet and exhaust valves of the engine. This can be achieved, for instance, using cam phasing mechanisms. Varying the valve timing can lead to a change in the characteristics of the engine and a power output in land mode which is less than the power output in marine mode.
15. For a simpler and somewhat cruder approach, the power control mechanism could act on the clutch which connects the engine to the driven road wheels. The clutch mechanism could be controlled to deliberately allow clutch slippage and therefore limit the power transmitted to the road wheels, even though the engine itself outputs the same amount of power both in land and water modes.
16. Another simple approach to limiting power output would be to warm the intake air prior to combustion, which could be done, for instance, by running hot coolant around the air intake with the flow of hot coolant switched on and off depending upon operating mode.
17. The body of the vehicle could be provided with moving flaps which are retracted during marine mode operation to make the vehicle more streamlined and then extended during land mode operation to give greater air resistance and restrict thereby the speed of the vehicle. The movable body parts of the vehicle could be a front screen of the vehicle, which could be tilted into a more upright position in land mode, or a spoiler. Also the air intake apertures in the vehicle body (which provide a flow of cooling air to the radiator(s) of the vehicle) could be provided in deployable scoops which are extended in land mode operation of the vehicle to increase air flow and to increase drag. The vehicle suspension could also be provided with a tilting mechanism which would tilt the vehicle with increasing speed in order that the vehicle presents a greater effective frontal area to increase drag.
18. It would be possible to fit the vehicle with a sophisticated braking system which would apply brakes to the road wheels to limit the top speed of the vehicle. This could be a function of a traction control system of the vehicle.
19. The engine could be provided with an alternator or other electrical charger which is switched in to be driven by the engine during land mode, but which is decoupled from the engine during marine mode so that the net power of the engine is reduced in land mode because of the power needed to power the electrical charger.
20. A very basic way of restricting the performance of the vehicle on land is to provide it with tyres which have high rolling resistance and high friction.
21. It is also possible to configure the vehicle with a first throttle control for road use and a second throttle control for marine use, with each throttle control being made automatically inactive depending upon the mode of operation. The road use throttle control would only allow the throttle to be opened part way and not a wide open throttle thereby restricting the power output during land operation. On the other hand, the marine mode operation would allow the vehicle to operate with wide open throttle and would not restrict the power output of the engine.
22. Many internal combustion engines are now provided with exhaust gas recirculation in order to improve the overall emissions of the engine. It would be possible to adapt an exhaust gas recirculation system to feed back sufficient exhaust gas into the combustion chambers that the overall power output of the engine was reduced. This would be done for land operation, whereas the exhaust gas recirculation would be reduced or stopped completely for water use.
23. Whilst in the drawings and as described above, the vehicle has a single internal combustion engine as its power plant, the vehicle could be provided with, for instance, two internal combustion engines. The transmission connecting the internal combustion engines to the jet drive/propeller and to the driven road wheels would operate under the control of the power control system in order to either power the jet drive/propeller using both engines, with the driven road wheels driven by only one engine, or alternatively to drive the jet drive/propeller with a first engine and the driven road wheels with a second, different engine. The second engine would have a reduced power output as compared with the first engine.
In the modes of operation described above, in which an absolute limit is placed on vehicle speed it may be desired to provide a warning light in the instrument cluster to warn the driver when the speed limit is reached.
For all of the embodiments described above there will be an electronic control system which senses whether the vehicle is in road mode operation or marine mode operation and then controls the power output of the engine accordingly. The simplest way of providing for this would be to sense whether the wheels are in their retracted or extended positions. The wheels will typically be extended or retracted under manual control and a sensor can easily be provided to detect which location they are in. The switch-over of engine power output or the switch of power available to the vehicle wheels will occur automatically on the sensing of a change of mode from water mode to land mode. The driver will not be allowed to override the action of the power control system.
Whilst sensing the position of the wheels will give the easiest way of detecting whether the vehicle is in land mode or water mode, other ways of detecting this are possible: for instances, sensors to detect the immersion of the hull in water, e.g. hull-mounted pressure sensors, or sensors detecting the presence of water in the intake pipe leading to a jet drive.
While a particular form of the present invention has been illustrated and described, it will also be apparent to those skilled in the art that various modifications can be made without departing from the spirit and the scope of the present invention. Accordingly, it is not intended that the invention be limited except by the appended claims. | Amphibious vehicle needs less power on land than on water. A control system is provided to limit power and/or speed on land, using: restriction of flow of fuel, air, or exhaust gases; heated intake air; exhaust gas recirculation; declutching of a supercharger; bypassing of a turbocharger; a variable throttle stop, dual throttles, or a switchable throttle damper; cylinder or intake valve deactivation; a dual length intake manifold; dual mode ignition or engine mapping; dual fuel—gasoline on water, compressed natural gas on road; variable compression ratios or valve timing; a clutch designed to slip; automatic brake application; or aerodynamic brakes. The suspension may tilt the vehicle to increase aerodynamic resistance. The road transmission may be geared to limit maximum speed. High rolling resistance tires or twin engines may be used. A sensor on retractable suspension may indicate whether the vehicle is on land or on water. | 1 |
CLAIM OF PRIORITY
The present application claims priority from Japanese patent application serial No. 2007-306751, filed on Nov. 28, 2007, the content of which is hereby incorporated by reference into this application.
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to delivery of contents via a network.
(2) Description of the Related Arts
Along with the improvement of terminal performance and the capacity increases of network lines and of hard disks, in recent years, content delivery systems have been made up. The content delivery systems deliver contents, including such kinds of data as image, video, audio, text, program, and explanatory information (meta-data), from a server to client terminals over an Internet Protocol (IP) network, thereby to enable users to watch and listen to the received contents at their terminals. IP television (IPTV) service for delivering such audiovisual works as television programs and movies by using this kind of content delivery has been developed.
Japanese unexamined patent publication No. 2005-135140 (Patent document 1) discloses an invention to accomplish an object of providing a technique with which a client who requested content can receive requested content delivery from a specific client having superior delivery quality and licensing conditions (See, paragraph [0012] of the Patent document 1) by sending from a server to the requesting client a list of clients to which the requesting client is connectable, so that the requesting client can select the optimum one in accordance with the delivery quality and licensing conditions out of the listed clients and receive content delivery from the selected client (See, paragraph [0013] of the Patent document 1).
Japanese unexamined patent publication No. 2006-72432 (Patent document 2) discloses an invention to accomplish an object of providing a peer-to-peer type content delivery system capable of balancing loads on the participating piers by providing a large number of dynamic peers DP and a center server CS for managing content delivery. Each dynamic peer DP notifies the center server CS of its own operating state, and the center server CS calculates and registers the load on each dynamic peer DP on the basis of the notified operating state. Each dynamic peer DP obtains a list of contents from the center server CS to search for the other dynamic peers DP each having the content it desires, and downloads the content from the least loaded dynamic peer DP. The system is further provided with a static peer SP for uploading a new content first. The content is delivered to dynamic peers DPs starting from the static peer SP (See, abstract of Patent document 2).
IPTV service is broadly classified into three types of service: streaming, download and progressive download.
In the streaming, a server delivers content data successively to a client, and the client represents video and audio from arrived data to present them to its user. This enables the user to watch and listen to the content on a substantially real time basis if a network has a sufficiently wide bandwidth.
In download, the client acquires all the content data from the server in advance, and starts representing of the content data for watching and listening after completing the storing of received content data. Because all the content data are delivered and stored in advance, the download type service enables the user to watch and listen to the content whenever and as many times as the user wants in the case where there is no need to watch and listen on a real time basis and to receive content delivery even if the network does not have a wide enough bandwidth.
Progressive download is positioning between the streaming type and the download type. In the progressive download, watching and listening of content are performed successively from content data having been stored in the terminal before completing the delivery of all the contents. The progressive download has an advantage that the user does not have to wait for the completion of all content data storing, the time for storing the content data is shortened substantially even if the bandwidth is not wide enough and the user can watch and listen to the content whenever and as many times as the user wants after completing the content data storing.
Commercial IPTV services, especially download-oriented services, are usually provided by a so-called server-client type system in which contents are distributed from a center server. In this system, content delivery is started when a user designates a desired content from among content lists offered by the center server.
In this system, for example, a part of the title, a text indicating the name of performer, genre attributes of the content, etc. that are designated by the user, are sent to the server. The server searches for the desired content by using the function of narrowing down the possible candidates according to a suitable content list.
As the content service provider has to take charge of many administrative processing, such as authentication of a terminal and a user that receive the content delivery as legitimate equipment and an authorized subscriber, charge accounting for each user who has contracted the content delivery service to play the content, managing the key information for enciphering content data and decrypting encrypted data to prevent unfair watching/listening of the content, etc., the server-client type is generally considered suitable for the content delivery service described above.
On the other hand, there is a peer-to-peer (P2P) type delivery as one of file sharing type delivery for delivering general contents by using PCs and the Internet. In this type of delivery, a terminal which is referred to as a peer or a client operates as a server to another terminal, and contents are delivered from one terminal to another terminal, namely from peer to peer. In this type, content delivery takes place in geometrical progression as a plurality of terminals perform successively the role of the server, unlike in the client-server type delivery in which a specified server carries out all the content delivery.
P2P type delivery is classified into a pure P2P type and a hybrid P2P type. In the pure P2P type, since every communication is carried out basically by peers with no dependence on the center server, the network has high tolerance to faults. It is also characterized by the capability to permit anonymity in mounting and a high efficiency of delivery.
Meanwhile, in the hybrid P2P type, content forwarding is carried out between peers, but resolution of content location and assignment of peers are carried out by the center server. That is, as the searching of content and peer having the content is performed by the center server and actual content delivery which needs a heavy processing load is carried out by peers, the hybrid P2P is a rational content delivery method permitting easy management of all terminal operations.
In considering these factors, techniques for spreading the IPTV service offering managed content delivery have been developed in the IPTV download delivery service as well by using a P2P type content delivery method, especially, by using a hybrid P2P type content delivery method.
For instance, in a hybrid P2P type contents delivery system according to Patent document 1, each peer is available content redelivery from a peer having good delivery quality and adequate licensing conditions with a long validity period. This type ensures stable delivery quality and licensing conditions because each client can receive content delivery from a peer having the best connection environment from among a plurality of peers.
According to Patent document 2, P2P type content delivery is realized by making each peer notify the center server of its own operation state so that the center server can select the least loaded peer.
SUMMARY OF THE INVENTION
Patent document 1 and Patent document 2 disclose, as peer selecting means, to use delivery quality of a network and licensing conditions or the state of peer load, and delivery procedures using them.
However, in these Patent documents, a redelivery peer is selected based on the network traffic or the load of the apparatus, and neither discloses anything about the legitimacy and the safety of the content and the peer or about how to assure the legitimacy and the safety of the content.
Since P2P type content delivery can deliver contents easily, however, it involves the problems of delivering contents without respecting the copyright of its producer, allowing evil data such as computer viruses to cause adverse impacts on a terminal and inviting illegitimate accessing to the terminal or an outflow of confidential data from the terminal while a user was unaware of them. Therefore, it is indispensable to solve these problems before expanding the use of IPTV services.
Especially in commercial IPTV services, many of users have no sufficient technical knowledge about a communication network, content delivery services and the construction of terminal for enjoying such delivery services.
Accordingly, it is an object of the invention to ensure adequate safety for the use of contents from service provider side.
It is another object of the invention to ensure the integrity of contents delivered to each user who purchased the right to watch and listen to the contents.
According to one aspect of the present invention, content delivery request information for requesting content delivery is transmitted from a terminal to a server, the server having received the content delivery request information from the terminal transmits to the terminal, a redirect instruction for instructing the terminal to transmit the content delivery request information to another terminal. Upon receiving the redirect instruction from the server, the terminal transmits to the other terminal, the content delivery request information, and the other terminal having received the content delivery request information delivers the content to the requesting terminal.
According to this method, it is able to realize safer content delivery. For instance, in the case of IPTV using a hybrid P2P type content delivery system, security and safety against problems regarding content delivery service is ensured for each user at a high level. From the standpoints of content producers and server operators, it is possible to reduce the risk of circulation of illegitimate contents. Furthermore, by rationally setting delivery peers to be connected, high speed content delivery and content delivery taking account of the state of terminal use can be realized.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an example of system configuration;
FIG. 2 shows an example of authentication information 101 ;
FIG. 3 shows an example of communication information 102 ;
FIG. 4 shows an example of account information 104 ;
FIG. 5 shows an example of content information 105 ;
FIG. 6 shows an example of content-possessing client information 109 ;
FIG. 7 shows an example of identifiers 121 and 141 which clients have;
FIG. 8 shows an example of processing flow by a server, a served client and an unserved client;
FIG. 9 shows an example of processing flow by the server, the served client and the unserved client (continued);
FIG. 10 shows an example of display screen for proxy delivery acceptance;
FIG. 11 shows an example of display screen for content selection;
FIG. 12 shows an example of priority factor calculation flow;
FIG. 13 shows an example of priority list of served clients;
FIG. 14 shows an example of display screen (collective display) for proxy delivery acceptance;
FIG. 15 shows an example of conditions regarding clients for proxy delivery; and
FIG. 16 shows an example of conditions regarding contents for proxy delivery.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Preferred embodiments will be described with reference to the accompanying drawings. However, the application of the invention is not limited to these embodiments. In describing the invention, contents are supposed to be program information composed of plural kinds of media including image, video, audio, text information, programs, etc.
FIG. 1 shows a basic system configuration for implementing the invention. A server 100 and clients 120 , 130 , 131 and 140 are connected to the Internet 150 at the center.
The server 100 includes, centering on an operation unit 107 , a communication unit 108 for communication with other equipment, especially clients, by using a network, a client managing unit 103 for managing clients, a content managing unit 106 for managing contents and a delivery managing unit 110 for managing the state of delivery.
The client managing unit 103 manages authentication information 101 for authenticating clients, communication information 102 indicating the state of communication with clients and account information 104 indicating the state of charge for each content.
FIG. 2 illustrates one example of authentication information 101 on clients. The authentication information indicates the client ID (client management number) of each client, a client equipment identifier unique to each client, and the owner of the client equipment together with the owner's residence and contact address.
FIG. 3 illustrates one example of communication information 102 . The communication information indicates, in association with the client ID, the address and the network port of each client, route information and line speed determined on previous communication of the client with the server.
In the processing described hereinafter, the server communication with each client by using these addresses and port number. Route information is detected by using common commands for detecting a router on the route, such as “tracert”. The line speed can be calculated as an average from the transmitted or received data size in communication between the client and the server and the time taken by that transmission or reception.
Although this description supposes the forms of Internet Protocol Version 4 (IPv4), some other form, such as IPv6 or telephone lines, may be used as well.
FIG. 4 illustrates one example of account information 104 . The account information indicates, in association with the client ID, payment method, a user name, IDs of delivered contents and the charge to be billed to the owner of the client for receiving content delivery service or playing, watching and listening to the delivered content. These categories of information managed by the client managing unit 103 may be recorded on a medium such as a hard disk and read out into a memory managed by the client managing unit.
The content managing unit 106 manages content information 105 including content data and other information associated with the content data. FIG. 5 illustrates the content information 105 . The content information comprises the content ID, explanatory information for indicating including the format and substance of each content, content data, content size and check sum to be used for guaranteeing the integrity of the content, key information for decrypting and playing the content enciphered by using RSA encrypting technique or the like to protect the content from any malicious third party on communication paths including the Internet, and a fee to be charged for receiving content delivery service or playing, watching and listening to the delivered content. The content information 105 can be considered as a storage unit for accumulating the content data.
These categories of information may be recorded on a medium such as a hard disk and read out into a memory managed by the content managing unit 106 . Also, they may be managed in separate groups as content data and the other data for explaining the content data (meta-data). Further, the server for possessing the content data and the server for possessing content information on the content data may as well be different servers. Thus, the server 100 may be a server for possessing no content data and managing content delivery by using content information on the content data in the way to be described afterwards.
The delivery managing unit 110 manages content-possessing client information 109 regarding clients to which content delivery has been already done. FIG. 6 illustrates the content-possessing client information 109 . The content-possessing client information includes, in association with the content ID, served client IDs indicating clients to which the content with the content ID has already been delivered.
Next, clients 120 , 130 , 131 and 140 will be described. The clients in the context of the invention will be separated in description into served clients 120 , 130 and 131 and an unserved client 140 . However, since each client operates as a servelet which functions both as a client and as a server in P2P type delivery, each client can operates as an unserved client regarding one content, but as a served client regarding the other content.
Although every client is supposed to have the same block configuration in the following description, the configuration does not need to be the same for all clients if each client can perform the processing steps described below. For instance, a client may be configured as a general purpose device such as a PC or a specific device such as a TV set.
The served client 120 , which also represents 130 and 131 for the sake of convenience of description, includes, centering on an operation unit 125 , an identifier 121 preset to identify the client equipment, a communication unit 124 for communication with other equipment through a network, a content managing unit 122 for managing contents, a display unit 126 for performing display for the user, an input unit 127 for receiving instructions from the user, and a setting unit 128 for the client.
Similarly, the unserved client 140 includes an operation unit 145 , an identifier 141 , a communication unit 144 , a content managing unit 142 , a display unit 146 , an input unit 147 and a setting unit 148 for the client. The display unit does not need to be a display that is unified with the client equipment, but may be an output unit for outputting data to be displayed on a display device separate from the client equipment.
The content managing units 122 and 142 of the respective clients manage content information 123 and 143 . These sets of content information are in the same form as the content information 105 in the server as shown in FIG. 5 , and various information items regarding contents having been already delivered to the respective clients are managed.
FIG. 7 illustrates the client equipment identifiers 121 and 141 assigned to each client equipment. The client equipment identifiers are symbol strings to warrant the uniqueness of each client by a predetermined formula, and may be held in association with the IDs of clients as illustrated.
Next, operations at the server 100 , the served clients 120 , 130 and 131 , and the unserved client 140 will be described. FIG. 8 and FIG. 9 illustrate processing flows in the server 100 , the served clients 120 , 130 and 131 , and the unserved client 140 . The flows will be described below in a time sequence. Each step of processing is supposed to be mainly executed by the operation unit of the server or the client in coordination with other units connected thereto. For communication, both the server and the clients use the communication unit 108 , and communication is carried out via the Internet, but detailed description of this aspect will be neglected for the sake of convenience.
First, a served client keeps a content (step 801 ) delivered from the server (step 821 ). The served client sets proxy delivery acceptance to ascertain the user's will as to whether perform delivery as proxy for the server in P2P type delivery according to the invention (step 802 ). FIG. 10 shows an example of display screen displayed for the proxy delivery acceptance. By outputting such a screen as illustrated to the display unit 126 of the served client in order to ask the user whether a request for performing content delivery on behalf of the server is acceptable from another user (the user of an unserved client), an instruction is received from the input unit 127 , which may be a remote controller, an operation panel, a mouse or the like. The result of the setting of proxy delivery acceptance is recorded in the client setting unit 128 .
Next, content delivery will be described. First, the server 100 transmits deliverable content information items, for instance, the title and description of the substance of the content and the names of performers, excepting some items such as key information and check sum out of the content information 105 , to the unserved client 140 (steps 822 and 841 ).
By using the display unit 146 and the input unit 147 the user of unserved client selects, on the basis of the delivered content information, the content desired by the user out of the contents deliverable from the server (step 842 ). FIG. 11 shows an example of display screen for content selection. Substantial items necessary for the user which are extracted out of the delivered content information are displayed so that the user selects one of contents that the user desires to be delivered by checking the content (step 842 ).
Instead of displaying all the contents to enable the user to make choice, narrow-down search by the genre or keywords may be allowed. This content search may be carried out by the server so that the searching result is transmitted from the server to the client. Although FIG. 11 supposes that content selection is made by checking the content to be delivered, this is not the only available way of expressing the choice, but content selection can also be made by some other methods, such as changing the color in which the selected content is displayed.
Next, in order to notify the server of the ID of selected content, content ID “100001” in the case of FIG. 11 , a connection to the server is established (steps 843 and 823 ), and the client is authenticated (steps 824 and 844 ). If the client fails authentication at steps 824 and 844 , the processing may be ended here because the client concerned cannot receive delivery service. In this case, the server may restrict available delivery service, for example, by changing the service condition so as to deliver contents inferior in resolution. A specific content may be delivered to display guidance in order to prompt subscription or registration with the server as a regular client and a regular user eligible for authentication.
In the authentication, the identifier 141 of the unserved client is transmitted to the server, the client managing unit collates the received identifier with the authentication information 101 and sends the result of authentication to the unserved client. The authenticated unserved client then transmits a content request to the server by using the content ID (steps 845 and 825 ).
In the server, the delivery managing unit obtains a client ID corresponding to the content from the content-possessing client information 109 (step 826 ), and the client managing unit 103 obtains corresponding communication information from the communication information 102 on the basis of the client ID (step 827 ). On this occasion, information regarding unserved clients is also obtained.
Next, a priority factor of the client is calculated based on the communication information obtained on each served client and the clients are arranged in the descending order of the priority factor (step 828 ).
Here, calculation of priority factors will be described. FIG. 12 shows the flow of priority factor calculation. First, the priority factor is initialized (step 1201 ), and communication information on an unserved client and a pertinent one of the served client is obtained.
Of the N routes (N is a predetermined constant) for the unserved client, the n-th route and the served clients' routes are compared (step 1203 ). If the same route is included (Yes at step 1203 ), the priority factor is multiplied by the n-th power of ½ (step 1204 ). Thus, the priority factor is multiplied by ½ every time the number of route increases by one between the unserved client and the served client.
If there is no route duplication among the N routes (No at step 1203 ), the priority factor is multiplied by the N-th power of ½ (step 1205 ). In order to assess the speed on the line toward the unserved client, the priority factor is multiplied by the speed on the downward line of the unserved client and the speed on the upward line of the pertinent served client (step 1206 ).
It is also assessed for a later acquisition whether reservation is already made for recording, watching/listening, delivery or the like, that are scheduled for the pertinent served client in M hours (M is a predefined constant) from now (step 1207 ). If there is a reservation within m hours (Yes at step 1207 ), the priority factor is multiplied by the (M-m)-th power of ½ (step 1208 ).
That is, any reservation in the immediate future is taken into account in the calculation so as to lower the priority factor. If no schedule is set or no reservation is made for the M-hour period from now (No at step 1207 ), no manipulation of the priority factor on account of a reservation is made.
In this way, the priority factor is figured out for all the served clients that have been acquired, and a list is prepared in the descending order of the priority factor (step 828 ). FIG. 13 shows an example of priority list of served clients. By listing them in the descending order with the calculated priority factor being used as the key, the served clients are assessed in a more rational order from the viewpoint of network architecture when the following steps are executed.
Referring back to FIG. 8 , description of the rest of the flow will be resumed. One served client is selected in the order of priority factors (step 829 ) and negotiations are started. If it is found that there is no list or no appropriate proxy server exists as a result of continuing negotiations to the last minute reveal (No at step 830 ), the server delivers the content to an unserved client (steps 831 and 846 , and steps 930 and 960 in FIG. 9 ).
The negotiations in this context means an attempt to establish connection to a client via a network, or making a judgment not to establish connection to this client after comparing its priority factor with priority factors of the other clients listed thereafter in the list when there are differences among various sets of information detectable by connection at that moment and used in the priority factor calculation and the result of priority factor recalculation gives a lower priority factor than the previous one, or the like. The pertinent client information may be updated on this occasion according to a newly obtained variety of information.
If a served client is found available from the list (Yes at step 830 ), an attempt is made to establish connection from the server to the served client (steps 832 and 803 ).
In order to carry out authentication after the establishment of connection, the client managing unit 103 makes collation by using the served client's identifier 121 and the server's authentication information 101 , and sends the result to the served client (steps 804 and 833 ).
Next, the intention of the user of the unserved client is informed based on the proxy delivery acceptance accomplished as previously stated (steps 834 and 805 ). If the user has no intention to accept (No at step 835 ), the attempt to establish connection with this served client is ended (steps 838 and 807 ), and the object of connection attempt is shifted to the served client having the next priority factor in the list to make a similar assessment (steps 829 through 835 ).
In place of the setting to confirm the user's intention at step 802 described above, the user's intention may be inputted at step 805 . In this case, the user's intention may be confirmed by displaying either the screen shown in FIG. 10 or a screen shown in FIG. 14 which indicates a plurality of proxy deliveries requested at the same time. In FIG. 14 , the title of the content, the ID of the requesting unserved client and a flag for indicating permission or refusal are displayed for each request.
When the user sets a permission flag by using an input unit, the display state of the flag is changed. A button for simultaneous setting may be provided to make possible Permit All 1402 or Refuse All 1403 . In order to prompt the user's proxy delivery acceptance on this occasion, a point-based user incentive scheme may be offered; the number of points may be predefined for each request, and the points are given to each client when the user has accepted to do and actually done a proxy delivery. The cumulative earned points are displayed on a screen 1401 of the display unit 126 to enable the user to check as necessary. The points given to each client may as well be managed by the server. This point-based user incentive scheme may be, for instance, the price for content watching/listening to be discounted at a preset rate, a certain discount to be made on the total charge or a condition for accessibility to some other service.
In the setting of proxy delivery acceptance at step 802 , the users' willingness or unwillingness to accept may be set as a precondition so that pertinence can be judged to semi-automate this procedure. For instance, a screen as shown in FIG. 15 can be used to add conditions for each unserved client to perform proxy delivery ( 1501 ), and “Always Permit” 1502 , “Always Refuse” 1503 or “Decide Each Time” 1504 is set for each client with the pertinent button. On this occasion, the user may set the client ID through the input unit as appropriate. By appropriately providing buttons on the intention-expressing screen as shown in FIG. 10 displayed when a delivery request is received, the user may sift the screen while holding the client ID having made the request.
When “Decide Each Time” 1504 is set, the user is enabled to operate on a screen like the one shown in FIG. 10 when a delivery request is received from the pertinent client. Semiautomatic expression of the intention is made possible by permitting or refusing without going through this procedure 1504 when “Always Permit” 1502 or “Always Refuse” 1503 is set, respectively. Alternatively, a condition may be added for each content on a screen like the one shown in FIG. 16 so as to set “Always Permit” 1602 , “Always Refuse” 1603 or “Decide Each Time” 1604 . On this occasion, the content or its ID may be set by the user through the input unit as appropriate. By appropriately providing buttons on the intention-expressing screen as shown in FIG. 10 displayed when a delivery request is received, the screen may be shifted while holding the ID of the requested content. When “Decide Each Time” 1604 is set, the user may operate on a screen such as the one shown in FIG. 10 when a delivery request is received from the pertinent client. Semiautomatic expression of the intention is made possible by permitting or refusing without going through this procedure 1604 when “Always Permit” 1602 or “Always Refuse” 1603 is set, respectively.
For the served client of a user who is willing to accept (Yes at step 835 ), the reservation status until the designated extent is inquired about (steps 835 and 836 ), a priority factor reflecting the reservation status is recalculated (step 837 ). This priority factor calculation is carried out according to the flow charted shown in FIG. 12 .
If the recalculated priority factor does not exceed a predetermined threshold (No at step 839 ), the attempt to establish connection with this served client is ended (steps 838 and 807 ), and the object of connection attempt is shifted to another served client having the next priority factor in the list to make a similar assessment (steps 829 through 835 ). By repeating the above assessment on every served client in the priority factor list, an appropriate served client is selected. If no appropriate served client is found, the server itself is selected.
If the recalculated priority factor exceeds the predetermined threshold priority factor (Yes at step 839 ), the pertinent served client is determined as the served client which should carry out the content delivery.
Next, a flow for performing subsequent actual content delivery after determining the served client which should carry out the content delivery will be described with reference to FIG. 9 .
Since the unserved client and the served client are already authenticated, communication for guaranteeing the unserved client to the served client is performed (steps 921 and 901 ). A redirect instruction is transmitted to the unserved client in order to guarantee the served client (steps 922 and 941 ). The “redirect” means to designate one of served clients as a proxy server for performing content delivery instead of the server.
Through these actions, the served client and the unserved client are mutually guaranteed by the server, and start communication settings to enable them to communicate over a firewall.
Next, a connection request is communicated between the unserved client and the served client (steps 942 and 902 ). After that, a delivery request of the desired content is transmitted (steps 943 and 903 ), and content is delivered from the served client to the unserved client. The unserved client stores the received content (steps 904 and 944 ).
Upon completion of the content delivery, the connection between the two clients is ended (steps 905 and 945 ), and the communication setting is also ended (steps 906 and 946 ).
Next, verification to determine whether the content has been correctly delivered will be described. This verification is realized between the unserved client and the server by collating information for verifying the uniqueness and integrity of the content, such as the size and check sum (the value of designated bytes out of the sum of adding up binary data from the beginning) of the content during or after delivery, with data in the content information stored in the server (steps 947 and 923 ).
For instance, the size of the delivered content is compared with the size of the pertinent content in the content information stored in the server. If the sizes are not found identical, integrity is denied and it may be judged that the content has not been correctly delivered. The criterion of the identity of the content sizes may allow, instead of complete equality, a difference in content size not exceeding a predetermined range to judge an acceptable identity.
Regarding uniqueness, for instance, the check sum of the delivered content is compared with that of the pertinent content in the content information stored in the server. If the check sums are not found identical, uniqueness is denied in the sense that the delivered content and the content indicated by the server's content information are different, and it may be judged that the content has not been correctly delivered.
The information to be used in the collation may be, for instance, parity, hash such as Cyclic Redundancy Check (CRC) of Message Digest Algorithm 5 (MD5) or some other verification technique.
Thus, the uniqueness and integrity of the content are secured, and the user of the unserved client is given a guarantee of the content. After that, account processing which includes updating of the account information 104 is performed by the content managing unit 103 and client managing unit 106 in the server. Whether the charge to the user should be decided when the delivery is completed or when the user plays the content for watching/listening may be selectable arbitrarily.
When it is judged by the above procedure that the content has been correctly delivered (steps 924 and 948 ), the server updates the various recorded information, such as route information, line speed, etc. between the served client and the unserved client ( FIG. 3 ) that is obtained at the time of connection (step 925 ), and terminates the processing at both the server and the unserved client.
If it is judged that the content has not been correctly delivered, delivery and storing of content are repeated again (steps 930 and 960 ) and the processing to ensure the uniqueness and integrity of the content is carried out. The number of times to limit the repeating of content delivery and storing may be designated in advance so that when the repeat number of the delivery reaches the predetermined number of times, the connection route, the status of server and the two clients are checked for any abnormality, thereby to start the delivery and storing of content again after such abnormality has been recovered.
In order to protect from piracy, disguise or the like, the identifier referred to in the foregoing description is desired to be stored under appropriate protection, for example, in the encrypted form or self-destruction form destructible at time of abnormality. The communication performed through the communication units of the server and the client is desirably to use data enciphering in order to achieve mutual trust and protection from external abuse by relying on some other technique such as Secure Socket Layer (SSL).
Although the contents referred to in the description of the invention are supposed to be program information composed of plural kinds of media, such as images, voice and character information, the applicable contents are not limited to them. For example, files to be used in personal computers (PCs), executable object data, e-mails, markup statements and scripts stating operations to be communicated with the World Wide Web (WWW), and general electronic data to be transmitted via networks are applicable as the content. Therefore, the invention can be extensively applicable to many industries using a network. | In hybrid peer-to-peer type content delivery, a server confirms user's intension as to content disclosure, guarantees content delivery by mutual authentication between a client to which content has been delivered and a client to which content has not been delivered, and guarantees the integrity of content having been delivered. Further, the server configures delivery connection based on the network relationship between the clients and priority factors taking account of a reservation status. | 7 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a control device for a high-pressure fuel system in a direct-injection internal combustion engine.
[0003] 2. Description of the Related Art
[0004] The direct-injection internal combustion engine includes a fuel control section that measures fuel pressure in a fuel rail and calculates injector valve opening time (injection pulse width) in accordance with the measured fuel pressure for the purpose of enabling an injector to inject a target amount of fuel. One of the problems with the direct-injection internal combustion engine is fuel pressure pulsation in the fuel rail. Fuel pressure pulsation occurs because fuel discharge from a high-pressure pump and fuel injection from the injector are intermittent. This fuel pressure pulsation may cause the injector's fuel injection amount to deviate from a target controlled variable, thereby incurring exhaust deterioration.
[0005] The other problems with the direct-injection internal combustion engine are, for instance, fuel leakage from a high-pressure system and defects in the injector and high-pressure pump. Fuel leakage and defects may reduce fuel control accuracy, thereby causing exhaust deterioration. Therefore, methods for estimating the fuel pressure from controlled variables of the injector and high-pressure pump are proposed as conventional technologies for solving the above problems. For example, a technology disclosed in JP-A-2000-234543 varies a control gain to cope with fuel pressure pulsation, whereas a technology disclosed in Japanese Patent No. 3587011 estimates the fuel pressure and compares it with the measured fuel pressure to detect a defect.
SUMMARY OF THE INVENTION
[0006] However, the above conventional technologies may cause exhaust deterioration and incorrect diagnosis when fuel properties change or different types of fuel (e.g., ethanol and gasoline) are mixed. The reason is that the above conventional technologies estimate the fuel pressure from only the elasticity coefficient of a specific fuel (e.g., gasoline). The use of fuels having different elasticity coefficients increases fuel pressure estimation error. Further, if, for instance, discharge dispersion, injection dispersion, and leakage are not considered in a situation where only the elasticity coefficient is estimated, fuel pressure estimation error increases in a startup region or low-load region. Therefore, the above conventional technologies suffer from the problem that they cannot be applied to fuel control and diagnosis of such regions.
[0007] The present invention has been made in view of the above circumstances. An object of the present invention is to provide a high-pressure fuel system control device that prevents exhaust deterioration, which may result from fuel pulsation or fuel system malfunction.
[0008] According to one aspect of the present invention, there is provided a control device including a fuel injection control section for controlling an injector, which injects fuel stored in a fuel rail that stores fuel pressure-fed from a high-pressure pump, wherein the fuel injection control section includes a homo-elasticity coefficient calculation section for calculating a homo-elasticity coefficient in accordance with a pressure change in the fuel rail, which is brought about by fuel discharge from the high-pressure pump, a fuel pressure estimation section for estimating pressure within the fuel rail in accordance with the homo-elasticity coefficient and controlled variables of the high-pressure pump and injector, and a fuel control section for calculating an injector pulse width in accordance with the pressure estimated by the fuel pressure estimation section and outputting an injector drive pulse to the injector in accordance with the calculated injector pulse width. The use of the configuration described above makes it possible to provide increased fuel pressure estimation accuracy and exercise accurate fuel control.
[0009] Further, if the homo-elasticity coefficient is estimated when a fuel discharge amount of the high-pressure pump is not smaller than a predetermined value, fuel pressure estimation accuracy increases.
[0010] Furthermore, the predetermined value is close to a maximum discharge amount of the high-pressure pump. The reason is that the use of such a predetermined value reduces discharge dispersion of the high-pressure pump.
[0011] Alternatively, the homo-elasticity coefficient calculation section estimates the homo-elasticity coefficient when a cam for driving the high-pressure pump is rotating at a speed not higher than a predetermined speed. The reason is that homo-elasticity coefficient calculation error will be reduced due to gradual fuel pressure changes.
[0012] Further, the homo-elasticity coefficient calculation means includes a leak amount calculation section for calculating the amount of fuel leakage from the high-pressure pump by using at least one of the angle of a cam for driving the high-pressure pump, the crank angle of an engine that coordinates with the cam, fuel temperature, engine water temperature, and the fuel pressure within the fuel rail.
[0013] Furthermore, an in-cylinder pressure estimation section is included to estimate the engine's in-cylinder pressure prevailing during fuel injection from at least one of an intake air amount, an engine speed, and fuel injection timing. Moreover, a fuel control section is included to correct an injection pulse of the injector in accordance with the in-cylinder pressure. The use of the configuration described above increases homo-elasticity coefficient estimation accuracy and particularly improves fuel control performance for startup.
[0014] According to another aspect of the present invention, there is provided a high-pressure fuel system control device that includes a high-pressure pump for pressurizing fuel and discharging the pressurized fuel to a fuel rail, an injector for injecting the fuel stored in the fuel rail, and a fuel pressure sensor for measuring the pressure of the fuel stored in the fuel rail, and controls the high-pressure pump and the injector in accordance with an output generated from the fuel pressure sensor, the high-pressure fuel system control device including: a homo-elasticity coefficient estimation section for estimating a homo-elasticity coefficient of fuel in accordance with a pressure change that occurs when a fuel discharge amount of the high-pressure pump is not smaller than a predetermined value; a fuel pressure estimation section for estimating fuel pressure within the fuel rail in accordance with the homo-elasticity coefficient and control target values for the high-pressure pump and the injector; a correction amount computation section which computes a correction amount for correcting an internal variable (fuel amount) of the fuel pressure estimation section in accordance with the fuel pressure estimated by the fuel pressure estimation section and the pressure measured by the fuel pressure sensor; and a fuel control section for controlling the high-pressure pump and the injector in accordance with the fuel pressure estimated by the fuel pressure estimation section. The use of the configuration described above provides robust control over discharge dispersion of the high-pressure pump and injection dispersion of the injector and particularly improves fuel control performance in a low-load region.
[0015] In addition, a homo-elasticity coefficient correction section is included. When an integrated value of the correction amount (Σ correction amount) is outside a predetermined range, the homo-elasticity coefficient correction section corrects the homo-elasticity coefficient to decrease the Σ correction amount. Alternatively, a homo-elasticity coefficient estimation section is included. When the Σ correction amount is outside the predetermined range, the homo-elasticity coefficient estimation section reestimates the homo-elasticity coefficient during idling. The use of the configuration described above maintains expected fuel control performance even when the homo-elasticity coefficient changes during operation.
[0016] Further, an malfunction judgment section is included. When the homo-elasticity coefficient is outside a predetermined range, the malfunction judgment section judges that the high-pressure fuel system is abnormal. Alternatively, when the Σ correction amount is outside the predetermined range after the homo-elasticity coefficient is corrected by the homo-elasticity coefficient correction section, the malfunction judgment section may judge that the high-pressure fuel system is abnormal. The use of the configuration described above makes it possible to make a diagnosis in accordance with the homo-elasticity coefficient and correction amount even at startup or in a low-load region.
[0017] Furthermore, a target fuel amount is set to determine the injector pulse width in accordance with the homo-elasticity coefficient. The use of this configuration makes it possible to detect the introduction of fuels (e.g., light oil and ethanol) having different homo-elasticity coefficients. Consequently, fuel injection can be performed in consideration of the calorific value and volatility of each fuel to avoid exhaust deterioration at startup.
[0018] The present invention can reduce exhaust emissions at startup because it begins to accurately control the fuel injection amount immediately after startup. Further, the present invention provides improved fuel pressure control performance in a low-load region because it is robust for fuel injection and discharge dispersion. Furthermore, the present invention can immediately detect high-pressure fuel system abnormalities, thereby making it possible to prevent abnormalities from developing and avoid exhaust deterioration due to abnormalities.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a diagram illustrating the overall configuration of a direct-injection internal combustion engine.
[0020] FIG. 2 is a diagram illustrating the configuration of a fuel control system.
[0021] FIG. 3 shows an example of a high-pressure pump.
[0022] FIG. 4 shows a set of timing diagrams that illustrate how the fuel control system operates.
[0023] FIG. 5 illustrates the relationship between pulse width and fuel pressure that are required for injecting a specific amount of fuel.
[0024] FIG. 6 is a typical timing diagram illustrating a fuel pressure that prevails at startup.
[0025] FIGS. 7A and 7B illustrate injector injection dispersion and pump discharge dispersion.
[0026] FIG. 8 is an overall block diagram illustrating an embodiment of the present invention.
[0027] FIG. 9 shows an example of a fuel amount correction block for startup.
[0028] FIGS. 10A and 10B present a timing diagram illustrating an embodiment of the present invention in addition to pulse width correction results.
[0029] FIGS. 11A and 11B show a pump discharge characteristic and a cause of flow rate decrease.
[0030] FIG. 12 is a typical block diagram illustrating a homo-elasticity coefficient setup section that is configured in consideration of leak amount.
[0031] FIG. 13 illustrates the relationship between the first injection pulse width prevailing after startup and the engine speed prevailing during injection.
[0032] FIG. 14 shows typical in-cylinder pressure changes in the engine.
[0033] FIG. 15 is a typical block diagram illustrating a fuel control section that is configured in consideration of in-cylinder pressure.
[0034] FIG. 16 shows the relationship between the first injector pulse width prevailing after startup and fuel injection timing in accordance with an embodiment of the present invention.
[0035] FIG. 17 is a typical flowchart illustrating an malfunction judgment process.
[0036] FIG. 18 illustrates fuel pressure and fuel injection pulse width that prevail while a homo-elasticity coefficient is being reestimated.
[0037] FIG. 19 shows an example of a method of performing the malfunction judgment process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] Embodiments of the present invention will now be described with reference to the accompanying drawings.
[0039] FIG. 1 is a typical diagram illustrating the overall configuration of a direct-injection internal combustion engine according to the present invention. Intake air, which is introduced to a cylinder 107 b , is taken in from an inlet 102 a of an air cleaner 102 . The intake air then passes through an air flow meter (air flow sensor 103 ), which is one of operating state measurement sections of the internal combustion engine, and enters a collector 106 through a throttle body 105 in which an electronically-controlled throttle valve 105 a is housed to control an intake air flow rate. The air flow sensor 103 outputs a signal that indicates the intake air flow rate. This signal is delivered to a control unit 115 , which serves as an internal combustion engine control device. The throttle body 105 includes a throttle sensor 104 , which detects the opening of the electronically-controlled throttle valve 105 a as one of the operating state measurement sections of the internal combustion engine. A signal output from the throttle sensor 104 is also delivered to the control unit 115 . The air taken into the collector 106 is distributed to intake pipes 101 , which are connected to cylinders 107 b of the internal combustion engine 107 , and then introduced into a combustion chamber 107 c of each cylinder 107 b.
[0040] Meanwhile, gasoline or other fuel is, from a fuel tank 108 , subjected to primary pressurization by a fuel pump 109 , adjusted for a predetermined pressure by a fuel pressure regulator 110 , subjected to secondary pressurization by a high-pressure fuel pump 111 , and pressure-fed to a fuel rail. The resulting high-pressure fuel is injected into the combustion chamber 107 c from an injector 112 , which is provided for each cylinder 107 . The fuel injected into the combustion chamber 107 c is ignited by an ignition plug 114 through the use of an ignition signal whose voltage is raised by an ignition coil 113 . A cam angle sensor 116 , which is mounted on an exhaust valve camshaft, outputs a signal for detecting the phase of the camshaft. This signal is delivered to the control unit 115 . The cam angle sensor may alternatively be mounted on an intake valve camshaft. A crank angle sensor 117 is mounted on a crankshaft to detect the rotation and phase of the crankshaft of the internal combustion engine. An output generated from the crank angle Tensor 117 enters the control unit 115 . An air-fuel ratio sensor 118 , which is installed upstream of a catalyst 120 in an exhaust pipe 119 , detects oxygen in an exhaust gas and outputs the resulting detection signal to the control unit 115 .
[0041] FIG. 2 is a schematic diagram illustrating the configuration of a fuel control system. A controller 201 includes an injector control device 202 and a high-pressure pump control device 203 . The injector control device 202 injects a target amount of fuel into the cylinder by controlling the injector 204 in accordance, for instance, with the air amount, air-fuel ratio, and engine speed. The high-pressure pump control device 203 raises the pressure of the fuel, which is taken in from the fuel tank 209 by the fuel pump 210 , to a target pressure by controlling the high-pressure pump 207 in accordance with an output generated from a fuel pressure sensor 206 , which is mounted on the fuel rail 205 , and an output generated from a cam angle sensor 208 for a cam that drives the high-pressure pump 207 .
[0042] FIG. 3 shows an example of the high-pressure pump. In this example, the fuel supplied through a tank fuel pipe when a plunger 301 moves up and down is taken into a pump chamber 302 and discharged into a fuel rail fuel pipe. The discharge amount of the high-pressure pump is adjusted by allowing a solenoid valve 304 to push open an intake check valve 303 during a plunger ascent and letting the fuel flow back toward the fuel tank. Therefore, the fuel is intermittently discharged in synchronism with an engine's cam angle.
[0043] FIG. 4 shows a set of timing diagrams that schematically illustrate the relationship between a plunger lift amount, a high-pressure pump drive signal (solenoid valve signal), an injector drive signal (injection pulse signal), and the fuel pressure measured in the fuel rail. The high-pressure pump takes in fuel while the plunger moves from the top dead center to the bottom dead center, and discharges fuel while the plunger moves from the bottom dead center to the top dead center. The fuel discharge amount is mainly determined by timing with which the solenoid valve closes (OFF angle). The discharge amount decreases as the OFF angle of the solenoid valve retards from the bottom dead center. Meanwhile, the injector opens an injection valve in accordance with the injection pulse signal. While the same fuel pressure is maintained, the injection amount increases with an increase in the time during which the injection pulse signal is open. In this instance, fuel pressure pulsation occurs so that the fuel pressure measured in the fuel rail increases when the high-pressure pump discharges fuel and decreases when the injector injects fuel.
[0044] FIG. 5 illustrates the relationship between the pulse width and fuel pressure that are required for injecting a target amount of fuel. It is generally known that the relationship between a pressure P 1 and pulse width T 1 providing a specific fuel amount when a predetermined injection pulse width T 0 is used at a predetermined pressure P 0 is expressed by the equation T 1 =T 0 *sqrt(P 0 /P 1 ). Thus, this relationship is usually used to correct the fuel pulse width in accordance with fuel pressure and obtain fuel injection amount robustness for fuel pressure. However, this causes the following technical problem.
[0045] FIG. 6 is a timing diagram illustrating a fuel pressure that prevails at startup. When cranking occurs to rotate a pump cam and let the pump to discharge fuel until a predetermined injection start pressure (5 to 8 MPa) is reached due to a discharge-induced pressure rise, the injector injects fuel. When the fuel explodes to let the engine autonomously rotate, the pump discharge amount is controlled so as to obtain a predetermined target pressure (10 to 15 MPa). The technical problem is an injection error due to a fuel pressure drop that is caused by fuel injection by the injector. The injection error can be corrected by estimating the fuel pressure drop. However, the conventional technologies use the elasticity coefficient of a particular fuel for fuel pressure estimation. Therefore, changes in the fuel properties and the mixture of different types of fuel may increase the amount of unburned fuel or incur a combustion failure, thereby causing exhaust deterioration. As such being the case, a method for compensating for the injection error arising from pressure changes caused by a discharge operation of the pump will be disclosed below.
[0046] The present invention estimates a homo-elasticity coefficient from a pressure change that occurs in the fuel rail due to a discharge operation of the pump, and exercises control and makes a diagnosis in accordance with the homo-elasticity coefficient. A control device according to an embodiment of the present invention will be summarized below.
[0047] FIG. 8 is an overall block diagram illustrating an example of the control device.
[0048] A homo-elasticity coefficient estimation section 801 estimates the homo-elasticity coefficient of the fuel in accordance with the controlled variables of the high-pressure pump and injector and the fuel pressure measured by the sensor. The homo-elasticity coefficient is an elasticity coefficient that takes the movement of fuel into account, and is defined by a pressure change in the fuel rail. For example, the homo-elasticity coefficient K is calculated from the equation K=V*dP/Xi, where V is a fuel rail volume, dP is the difference between the fuel pressure measured before a discharge and the fuel pressure measured after a discharge, and Xi is a pump discharge amount.
[0049] A fuel pressure estimation section 802 uses, for instance, the equation Pe=K/V(Σ(Xi−Xo)+Xc) to estimate the fuel rail fuel pressure in accordance with the controlled variables of the high-pressure pump and injector, homo-elasticity coefficient, and correction amount (described later). Pe is an estimated fuel pressure, K is a homo-elasticity coefficient, V is a fuel rail volume, Xi is a pump discharge amount, Xo is an injector injection amount, and Xc is a correction amount.
[0050] A correction amount computation section 803 computes the correction amount in accordance with the estimated fuel pressure and the fuel pressure measured by the sensor. It is assumed that the correction amount is computed by using, for instance, the equation Xc=(Pe−P)*C, where Xc is the correction amount, Pe is the estimated pressure, P is the measured fuel pressure, C is a predetermined coefficient that is calculated in accordance with the operating state and called an observer gain. The observer gain is determined, for instance, by a pole assignment method or an optimal regulator method. The use of the correction amount computation section 803 makes it possible to estimate a preferred fuel pressure. Further, Xc may be regarded as equal to Σ(Pe−P)*C and updated as needed.
[0051] An malfunction judgment section 804 judges in accordance with the homo-elasticity coefficient and correction amount whether the high-pressure fuel system is abnormal. A fuel control section 805 controls the pump discharge amount and injector injection amount in accordance with the estimated fuel pressure.
[0052] Further, another problem, which is described below, can be solved.
[0053] FIGS. 7A and 7B illustrate injector injection dispersion and pump discharge dispersion. If control is exercised so that the pulse width is close to an invalid injection pulse width, which disables a fuel injection function, or that an instructed pump discharge angle is close to a pump cam top dead center, an increased fuel pressure estimation error may occur. Thus, an erroneous judgment might be formed to conclude that the high-pressure fuel system is abnormal.
[0054] The above problem occurs because the elasticity coefficient of a predetermined fuel is calculated or estimated to calculate the fuel pressure.
[0055] Therefore, if the homo-elasticity coefficient is calculated when the injection pulse width is somewhat greater than the invalid injection pulse width or when the pump discharge amount is rather large, it is possible to reduce the error resulting from injection dispersion and discharge dispersion.
First Embodiment
[0056] A case where an embodiment of the present invention is applied to startup fuel control will now be described with reference to FIGS. 9 , 10 A, and 10 B.
[0057] FIG. 9 shows an example of a fuel amount correction block for startup. A homo-elasticity coefficient estimation section 901 judges in accordance with the pump controlled variable and crank angle signal or cam angle signal whether the pump discharge amount is not smaller than a predetermined value (is close to a maximum discharge amount preferably), and estimates the homo-elasticity coefficient in accordance with the encountered fuel pressure change and the aforementioned definition. In this instance, the homo-elasticity coefficient may be corrected in accordance with a temperature change from the fuel temperature (or water temperature) prevailing at the time of homo-elasticity coefficient estimation to ensure that the homo-elasticity coefficient increases with an increase in the temperature. The reason is that the value dP increases with an increase in the fuel temperature. A target injection amount calculation section 902 calculates a fuel injection amount in accordance with the water temperature and crank signal. A target injection amount should preferably be calculated by calculating a fuel amount that withstands friction and provides a predetermined air-fuel ratio in relation to an air amount. The fuel amount may be calculated by using a map based on a water temperature signal and crank angle signal or by using any other means. Further, the fuel is preferably identified in accordance with the estimated homo-elasticity coefficient. Then, a target fuel amount is calculated in accordance with the identified fuel. A fuel pressure estimation section 903 estimates the fuel pressure within the fuel rail and a pressure change caused by fuel injection from the injector in accordance with the homo-elasticity coefficient and target injection amount. A fuel control section 904 controls an injector drive pulse width in accordance with the target injection amount and fuel pressure change. The injector drive pulse width can be calculated, for instance, from the equation Ti=D*Xo+Ti0, where Ti is a fuel injection pulse width, D is an injector coefficient to be calculated according to pressure, Xo is a target fuel injection amount, and Ti0 is an invalid injection pulse width to be calculated according to pressure. Further, when the injector coefficient is calculated by using the value Pe−dPe/2, which is obtained by subtracting half the pressure change dPe from the pressure Pe estimated before injection, while the invalid injection pulse width is calculated by using the pressure Pe estimated before injection, a target amount of fuel can be injected from the injector while compensating for the fuel pressure change. Since the equation dPe=K/V(Xi−Xo+Xc′) is used for calculation, Xc′=(Pe−P)*C.
[0058] FIGS. 10A and 10B present a timing diagram illustrating an embodiment of the present invention in addition to pulse width correction results. The timing diagram in FIG. 10A shows fuel pressure changes at startup and the first injector drive pulse signal generated for startup. If the fuel pressure change encountered when the pump discharge is maximized is dP A , the first injector pulse width is T B , and the water temperature, engine speed, and injection start pressure virtually remain unchanged, the relationship shown in FIG. 10B is obtained. The reason is that an increase in the fuel pressure change dP increases the homo-elasticity coefficient and increases the fuel injection pulse width T B for correction purposes. Therefore, if leakage occurs, the estimated homo-elasticity coefficient becomes great. This results in the output of a pulse width greater than normal.
Second Embodiment
[0059] Control and diagnosis performed in consideration of leakage from the plunger will now be described with reference to FIGS. 11 to 14 .
[0060] FIGS. 11A and 11B show a pump discharge characteristic and a cause of flow rate decrease. FIG. 11A shows a maximum discharge amount per discharge at various engine speeds. As shown in FIG. 11A , the discharge amount decreases in a low engine speed region and high engine speed region. The cause of such a discharge amount decrease is indicated in FIG. 11B . The flow rate decreases in the low engine speed region because the fuel leaks from a gap in the pump plunger when the engine speed is low. The flow rate of leakage depends on the viscosity of fuel and the pressure within the fuel pump chamber. More specifically, the leakage flow rate increases with a decrease in the viscosity and with an increase in the pressure. It is therefore preferred that the homo-elasticity coefficient be estimated in consideration of leak amount particularly during an engine cranking period and in a low engine speed region prevailing before complete explosion in the engine. It should be noted that the discharge amount decreases in the high engine speed region due to delayed discharge valve closure. The discharge amount decreases because the fuel flows backward (returns) from the fuel rail to the pump chamber before valve closure. The amount of this fuel return considerably varies although it increases with an increase in the fuel pressure within the fuel rail. Therefore, it is preferred that the homo-elasticity coefficient be estimated when the engine speed is not higher than a predetermined speed.
[0061] FIG. 12 is a block diagram illustrating a typical method of estimating the homo-elasticity coefficient in consideration of leak amount. A discharge amount calculation section 1201 calculates a basic discharge amount Xo, which is determined by the operation of a pump discharge valve, in accordance with a pump controlled variable, crank angle signal, fuel pressure signal, and the like. A leak amount calculation section 1202 calculates a leak amount from the cam angle signal, crank angle signal, water temperature signal, fuel temperature signal, and fuel pressure signal. The leak amount can be calculated, for instance, by using the equation X1=Σ(P−P 0 )*J, where X1 is the leak amount, P is a fuel pressure sensor value, P 0 is an atmospheric pressure, and J is a viscosity coefficient that varies with the fuel temperature. Engine water temperature may be used instead of the fuel temperature to estimate the fuel temperature. Σ provides integration while the fuel pressure is changed by a discharge operation. Furthermore, a fuel pressure difference calculation section 1203 calculates a pressure difference DP based on the difference between the fuel pressure measured before a discharge and the fuel pressure measures after a discharge. A homo-elasticity coefficient calculation section 1204 calculates the homo-elasticity coefficient from the discharge amount, leak amount, and pressure difference. The homo-elasticity coefficient can be calculated, for instance, by using the equation K=V*DP/(Xi−X1), where K is a homo-elasticity coefficient, V is a fuel rail volume, DP is a pressure difference, Xi is a basic discharge amount, and X1 is a leak amount.
[0062] FIG. 13 illustrates the relationship between the first injection pulse width prevailing after startup and the engine speed prevailing during injection in a situation where leakage compensation is provided. Even if the pressure changes brought about by pump discharge operations are substantially equal, the homo-elasticity coefficient increases when the leak amount is considered. Therefore, the estimated pressure change is great. Thus, the fuel pulse Tb is greater than in a case where the present invention is not applied. Consequently, control and diagnosis can be performed with increased accuracy.
Third Embodiment
[0063] Control and diagnosis performed in consideration of in-cylinder pressure of the engine will now be described with reference to FIGS. 14 to 15 .
[0064] FIG. 14 shows in-cylinder pressure changes in the engine. Fuel injection occurs due to the difference between fuel pressure and in-cylinder pressure. The peak of in-cylinder pressure tends to lower when the timing of intake valve closure is retarded. However, when fuel is injected during a compression stroke at startup, control and diagnosis can be performed with increased accuracy by compensating for the in-cylinder pressure.
[0065] FIG. 15 is a block diagram illustrating a fuel control section that is configured in consideration of in-cylinder pressure. An in-cylinder pressure estimation section 1501 estimates an in-cylinder pressure prevailing during fuel injection from an air flow rate, engine speed, and fuel injection timing. The in-cylinder pressure can be estimated, for instance, by preparing a map shown in FIG. 14 and decreasing a map reference value for correction purposes in accordance with the engine speed and air amount. A fuel pulse width calculation section 1502 then adds an in-cylinder pressure correction to a fuel pressure change correction. More specifically, when the fuel injection pulse width (Ti=D*Xo+Ti0) is to be calculated, it is assumed that the pressure used to calculate an injector coefficient D is equal to Pe−Dpe+P0−Pc, where Pe is an estimated fuel pressure, Dpe is a pressure change, P0 is an atmospheric pressure, and Pc is an in-cylinder pressure prevailing during fuel injection.
[0066] FIG. 16 shows the relationship between the first injector drive pulse width prevailing after startup and fuel injection timing in a situation where in-cylinder pressure compensation is provided. In the case of intake stroke injection, the in-cylinder pressure is not compensated for because it is equal to atmospheric pressure. In the case of compression stroke injection, however, the fuel pulse width increases in accordance with the in-cylinder pressure. Therefore, normal operations of the fuel control section can be verified by measuring the fuel injection pulse signal timing and pulse width.
Fourth Embodiment
[0067] An malfunction judgment method based on a correction amount and homo-elasticity coefficient will now be described with reference to FIGS. 17 to 19 .
[0068] FIG. 17 is a flowchart illustrating an malfunction judgment process. Step S 1701 is performed to calculate a Σ correction amount. If the Σ correction amount is obtained, for instance, by performing an addition for each of predetermined number of cam revolutions, it can be used for malfunction judgment based on estimated fuel pressure and measured fuel pressure. The predetermined number of cam revolutions may be the number of revolutions required for injection in all cylinders or the number of revolutions required for injecting a specific amount of fuel. Step S 1702 is performed to judge whether the Σ correction amount is within a predetermined range that is defined according to injection and discharge dispersion. If the Σ correction amount is within the predetermined range, the flow concludes that no malfunction exist, and then skips the subsequent steps. If, on the other hand, the Σ correction amount is not within the predetermined range, the flow proceeds to step S 1703 . Step S 1703 is performed to judge whether the homo-elasticity coefficient was reestimated (as described later) a predetermined period of time ago (predetermined number of injections, predetermined amount of injection, etc.). If the homo-elasticity coefficient was reestimated, the flow proceeds to step S 1706 . If not, the flow proceeds to step S 1704 . Step S 1704 is performed to reestimate the homo-elasticity coefficient.
[0069] An example of a method of reestimating the homo-elasticity coefficient will now be described with reference to FIG. 18 . FIG. 18 illustrates fuel pressure and fuel injection pulse width that prevail while the homo-elasticity coefficient is being reestimated. The homo-elasticity coefficient is reestimated in an idle state where the cam revolving speed is low. For homo-elasticity coefficient reestimation, at least one pump discharge operation is performed by using a value not smaller than predetermined value (so as to provide maximum discharge preferably) (reestimation operation), and the homo-elasticity coefficient is reestimated in accordance with the resulting pressure change. The method for reestimating the homo-elasticity coefficient is not described here because the homo-elasticity coefficient can be estimated by using a method according to any one of the foregoing embodiments. Further, whether the homo-elasticity coefficient could be reestimated can be determined by measuring the fuel injection pulse width before and after a reestimation operation. The reason is that fuel pulse widths measured before and after reestimation differ depending on the homo-elasticity coefficient estimation result even when the same target fuel pressure is adopted. In conjunction with homo-elasticity coefficient reestimation, if the Σ correction amount is outside the predetermined range, the homo-elasticity coefficient may be corrected in accordance with the fuel temperature or water temperature so that the estimated fuel pressure approximates to the measured fuel pressure.
[0070] Returning to FIG. 17 , step S 1705 is performed to judge whether the reestimation result is within the predetermined range. If the reestimation result is within the predetermined range, the flow terminates the process. If not, the flow proceeds to step S 1706 . In step S 1706 , the malfunction judgment process is performed.
[0071] FIG. 19 shows an example of a method of performing the malfunction judgment process in step S 1706 . When the homo-elasticity coefficient is below a normal range, it is judged that a discharge malfunction exists. For example, a decrease in the discharge amount of a low-pressure pump, a clogged fuel filter in a low-pressure pipe, and a faulty high-pressure pump valve may be regarded as typical failure modes. A warning may be issued to prompt for the check of such failure modes. If, on the other hand, the homo-elasticity coefficient is above the normal range, it is judged that a fuel pressure sensor malfunction or fuel malfunction exists. For example, a noise entry into the fuel pressure sensor, a faulty fuel pressure sensor gain, and an erroneous mixture of fuel and water or other liquid having an unduly high homo-elasticity coefficient may be regarded as typical failure modes. A warning may be issued to prompt for the check of such failure modes. If the Σ correction amount is shifted toward a plus (+) side and displaced out of a normal range while the homo-elasticity coefficient is within the normal range, it is judged that a fuel injection malfunction exists. In this instance, it is conceivable that the injector may be clogged. Therefore, a warning may be issued to prompt for the check of the injector or control may be exercised to unclog the injector (e.g., by injecting the fuel at high pressure). If, on the other hand, the Σ correction amount is shifted toward a minus (−) side and displaced out of the normal range while the homo-elasticity coefficient is within the normal range, it is judged that fuel leakage has occurred. For example, leakage from a high-pressure fuel pipe joint and leakage from a seal section of the injector or fuel pump may be regarded as typical failure modes. A warning may be issued to prompt for the check of such failure modes. Further, safe control may be exercised to avoid increased leakage by lowering the fuel pressure from its normal level. | The present invention reduces exhaust emissions at startup, provides improved fuel pressure control performance in a low-load region, and detects high-pressure fuel system abnormalities. Disclosed is a high-pressure fuel system control device which includes a high-pressure pump for pressurizing fuel and discharging the pressurized fuel to a fuel rail, an injector for injecting the fuel stored in the fuel rail, and a fuel pressure sensor for measuring the pressure of the fuel stored in the fuel rail, and controls the high-pressure pump and the injector in accordance with an output generated from the fuel pressure sensor. The high-pressure fuel system control device includes a homo-elasticity coefficient estimation section for estimating a homo-elasticity coefficient of fuel in accordance with a pressure change which occurs when a fuel discharge amount of the high-pressure pump is not smaller than a predetermined value; a fuel pressure estimation section for estimating fuel pressure within the fuel rail in accordance with the homo-elasticity coefficient and control target values for the high-pressure pump and the injector; and a fuel control section for correcting an injection pulse of the injector in accordance with the fuel pressure estimated by the fuel pressure estimation section. | 5 |
The invention described herein was made in the performance of work under a NASA contract (NAS 9-12540) and is subject to the provisions of section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 U.S.D 2457).
BACKGROUND OF THE INVENTION
The present invention relates to pressure vessels for storing highly pressurized fluid material, and particularly to portable, lightweight pressure vessels of the type wherein a thin, lightweight metallic liner having a cylindrical portion and a pair of dome-shaped end portions is completely overwrapped by a plurality of layers of filament material. The invention is particularly applicable to liners wrapped with resin-coated, single-glass filaments (commonly called wet-windings or pre-impregnated windings). The present invention further relates to an overwrapping technique wherein the filament wrapping sequence is specifically designed to reinforce the junction of the cylindrical portion with each of the dome portions.
The term "completely overwrapped", as used herein and in the art, encompasses a vessel in which the cylindrical portion and the dome-shaped end portions are completely overwrapped, but which also may include small neck-shaped portions at the outer extremities of the dome-shaped portions which may, or may not, be overwrapped. This will be readily apparent to those skilled in the art.
A pressure vessel made in accordance with the present invention may be particularly designed for use in a compressed air breathing system of the type which would be carried by a fireman or scuba diver. Pressure vessels of this type must, of course, be designed with a view toward obtaining minimum weight-maximum volume characteristics, while nonetheless being capable of satisfying the safety objectives of federal and local regulatory agencies. For example, a pressure vessel made in accordance with the present invention has been specifically designed to satisfy the following specifications:
1. Maximum weight of 9.0 pounds,
2. Maximum operating pressure of 4500 PSIG (charge pressure of 4,000 PSIG),
3. Minimum contained volume of 280 cubic inches,
4. Proof pressure 6750 PSIG,
5. Minimum burst pressure of 9,000 PSIG,
6. Inexpensive enough to justify commercial production.
It should be noted that the foregoing specifications are set forth basically as an example of the characteristics which a pressure vessel manufactured in accordance with the present invention can satisfy. More particularly, the foregoing specifications indicate the high operating pressures (i.e. 4500 PSIG for example) at which a pressure vessel in accordance with the present invention can function and yet be relatively light in weight and inexpensive enough to satisfy commercial production cost requirements.
It is contemplated that pressure vessels for many and varied applications may be manufactured in accordance with the present invention. Further examples of pressure vessels which can be made in accordance with the present invention include skin diving breathing apparatus, and storage bottles for cryogens, chemicals, fuels and gases. In fact, the method of manufacture in accordance with the present invention may be utilized to produce any overwrapped vessel where both polar and cylindrical reinforcement is utilized. Naturally, the specifications and operating characteristics may vary for pressure vessels for uses other than those set forth in the specific example set forth above.
Known pressure vessels which can operate at high pressures include all metallic vessels. An all metallic vessel which would satisfy the strength requirements for operating at high pressures generally requires a grade of steel whose cost makes commercial production of such a vessel unfeasible.
Pressure vessels which are known and which are less expensive to produce are those where a liner is overwrapped with a plurality of filament layers. Typical of the overwrapping technique for such a vessel is a 2-step overwrapping technique wherein a liner is completely overwrapped in the polar direction, followed by a plurality of circular windings about the cylindrical portion. Particularly when overwrapping is performed by wet winding, and the 2-step wrapping sequence is used, the vessel is generally inadequately reinforced at what applicant has found to be the most critical area of the vessel, i.e., the junction of the cylindrical region with the dome region. This is because filament material cannot be effectively wound cylindrically over the junction or it would tend to slough or slip down the dome area.
SUMMARY OF THE PRESENT INVENTION
The present invention discloses a completely overwrapped pressure vessel which is suitable for withstanding considerable fluid pressures, as well as being light enough in weight to be carried on a fireman's back, and inexpensive enough to justify commercial production cost requirements. In terms of cost and weight specifications the use of aluminum as a liner, and of S-2 fiberglass for the filament have been found to be particularly satisfactory. Of course, the present invention can be utilized to produce pressure vessels which meet specifications other than the aforesaid specific design specifications.
Moreover, the foregoing materials have been found to be compatible for achieving an advantageous prestress condition for the completely overwrapped pressure vessel. Specifically, since the operating pressures of the vessel will generally exceed the yield strength of the metallic liner, it has been found that a prestressed relationship may be induced between the overwrap and the liner causing both the overwrap and the liner to operate elastically through a strain range which exceeds the liner strain range for the operating pressures. Such a stress relationship also serves to increase the buckling strength of the liner.
The present invention also relates to an overwrapped pressure vessel wherein wrapping of filament material is effected in a manner which insures that cylindrically wound filament material covers the junctions between the cylindrical part of the liner and the hemispherical-shaped dome portions. This is accomplished by a four-step overwrapping technique wherein (1) polar oriented filament is wound to completely overwrap the liner, (2) cylindrically oriented filament material is then wound which covers the cylindrical portion and the junctions of the cylindrical portion with each dome portion, (3) additional polar oriented filament material is wound to hold the cylindrically wound filament against movement relative to the liner, and (4) additional cylindrically oriented filament material is wound over the central portion of the vessel.
Accordingly, it is an object of the present invention to manufacture an overwrapped pressure vessel wherein the overwrapping sequence is designed to reinforce the area at the junction of the cylindrical and dome-shaped portions of the vessel liner.
It is another object of the present invention to manufacture a completely overwrapped pressure vessel wherein a predetermined compressive stress has been induced into the metallic liner.
These and other objects and advantages of the present invention will become further apparent from the following description and the accompanying drawings wherein:
FIG. 1 is a schematic view of a liner and illustrating one type of filament winding;
FIG. 2 is a schematic view of a liner and illustrating another type of filament winding;
FIG. 3 is a view of the pressure vessel after the first two winding steps have been performed;
FIG. 4 is a composite view of a completely overwrapped pressure vessel, with a section of the second polar oriented wrap cut away;
FIG. 5 is a cross-sectional view of a completely overwrapped pressure vessel, taken substantially of section 5 of FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 illustrate the overall shape of the vessel liner, and the two types of windings which are performed to practice a part of the present invention. As clearly shown in FIGS. 1 and 2, liner 10 includes a cylindrical portion 12, and a pair of hemispherical-shaped dome portions 14 at each end of the cylindrical portion. At least one dome portion 14 includes a neck portion 16, and the neck portion will contain a fluid port therein. In FIGS. 1 through 5, fluid port 17 is shown at one end of the vessel, and the other end is suitably contoured, as at 21, but does not contain a fluid port. Naturally, suitable stopper means such as 19 will be provided to seal the fluid ports in the neck portion.
FIG. 1 illustrates a pattern for winding single fiberglass filaments 18 in what will hereinafter be referred to as the polar oriented direction. The filaments encircle the dome portions of the liner, and extend at an acute angle to the longitudinal axis of the cylindrical portion 12.
FIG. 2 illustrates a pattern for winding the single fiberglass filaments 18 in what will hereinafter be referred to as the cylindrically oriented direction. The filaments encircle the liner at substantially right angles to the longitudinal axis of the cylindrical portion.
It should be noted at this point that while the drawings illustrate the filaments 18 as having considerable cross-sectional dimension, and illustrate the overwrapped vessel as if the various overwraps each comprised only a single layer of filament material, they have been shown as such simply for illustration purposes. In reality the filaments will be of a very small cross section and during the wrapping of filament material in a particular direction the filaments will be wound in many turns and may therefore make up many layers of filament material. Of course, this will be readily apparent to those skilled in the art.
A vessel formed by the method of the present invention may be seen by reference to FIGS. 4 and 5. In FIG. 4, portions of the overwrap material have been cut away to better illustrate the overwrap pattern which is an aspect of the present invention. As shown in FIGS. 4 and 5, the overwrap pattern includes a polar oriented filament overwrap 20 which covers the entire surface of the liner and which is in engagement therewith. Cylindrically oriented filament overwrap 22 overlies the polar overwrap 20 and, as shown in FIGS. 3, 4 and 5, includes a portion 24 which covers the junction of the cylindrical portion of the liner and the dome portion of the liner (the area of the liner designated 25) and extends over part of the dome portion 14. Some sloughing of filament material may occur at the neck and end portions as shown in the drawings. However, such sloughing does not have an appreciable effect on the operating performance of the pressure vessel in accordance with the present invention.
The second polar filament overwrap 26 is shown covering the first cylindrrical overwrap 22 and that second polar overwrap 26 is in fact applied in a similar fashion to the first polar overwrap, and thereby has the effect of holding the cylindrical overwrap 22 against movement relative to the liner. (Note that in FIG. 5 the outline of the portion of the overwrap material near the neck of the vessel is defined in broken lines and is labeled 29. This is only for illustration purposes, but in practice the polar overwrap 26 will appear similar to polar overwrap 20, as shown in FIG. 3, in the vessel neck area). The final step in applicant's overwrapping technique involves the application of the top cylindrical filament overwrapping material against the liner. As particularly depicted in FIGS. 4 and 5, the top cylindrical overwrap 28 does not extend over the junction between the cylindrical portion and either dome portion.
The preferred embodiment of the present invention includes aluminum as a liner material. The choice of aluminum is dictated because of its high strength/density ratio, low modulus, outstanding toughness, and environmental compatibility. In the specific preferred embodiment of applicant's invention, the aluminum liner is made with a 6000 series aluminum alloy specifically 6070-T6 aluminum. Further, referring specifically to FIG. 5, it will be clear that the liner is formed of a fairly uniform thickness, particularly where the cylindrical and dome portions meet.
The selection of a suitable filament material involves two primary considerations, cost and fiber strength. In the preferred embodiment of the present invention the above requirements may be best satisfied through the use of Owens Corning S-2 fiberglass. Furthermore, in the preferred embodiment it has also been found that a suitable resin which is compatible with the aforesaid fiberglass may comprise Epon 828/1031/NMA/BDMA resin. Of course, other resins and filaments could be utilized.
The suitable selections of the liner material and the filament material should also be determined by taking into consideration the criterion that the liner material be mechanically compatible with the overwrapped material. Compatibility in this sense means that the strain imparted to the liner during pressurization and the corresponding strain of the glass overwrap must be reversible during depressurization of the vessel, i.e., since the filament strains elastically throughout the operating pressurization and depressurization cycles, the liner should also strain elastically during such cycles. Moreover, it must be reversible for each cycle without liner malfunction. The concept of mechanical compatibility in cylindrical vessel was reported in the Journal of Spacecraft and Rockets, July, 1967, p. 872, in an article by R. H. Johns and A. Kaufman, entitled: "Filament Overwrapped Metallic Cylindrical Pressure Vessels."
In the practice of the present invention the force balance between the liner prestressed in compression and its overwrap prestressed in tensiion is obtained before the vessel is placed in service. By correctly matching the material stresses, the liner may operate elastically through a greatly increased strain range and the overwrap can be used at efficient stress levels. The prestress condition is obtained by putting a newly-fabricated vessel through a "sizing" pressurization cycle where the liner is strained beyond its proportional limit and yields as much as 2%. When depressurized, the desirable stress state is attained because the metal unloads elastically and is forced into compression by the elastic overwrap.
The design characteristics of a completely overwrapped fiberglass pressure vessel are detailed and are therefore preferably determined with computer assistance. A suitable computer program for this purpose is entitled: "Computer Program for the Analysis of Filament Reinforced Metal-Shell Pressure Vessel," and may be found in NASA Scientific and Technical Aerospace Reports, Feb. 8, 1968 issue, v6, n3, page 419, the disclosure of which is hereby incorporated by reference.
The required computer program input parameters include pressure vessel geometry, liner material properties, filament material properties, filament and longitudinal metal stresses present upon winding, and design limit conditions. For the preferred embodiment of the present invention the variable program input parameters selected for the vessel include: liner thickness, filament design stress, design pressure, and sizing pressure. Other selected parameters may be dictated by performance requirements (vessel length and diameter which affect volume), or as a result of material selection (density, modulus and Poisson's ratio).
The computer output will then include such data as: dome contour, axial and hoop overwrap thickness, stress values (at sizing pressure, zero pressure, operating pressure, proof pressure, and at required minimum burst pressure), along with projected vessel component weights and volumes.
For the vessel to be designed to the aforementioned specifications, i.e., operating pressure of 4500 PSIG (charge pressure of 4000 PSIG), a proof pressure of 6750 PSIG and a minimum burst pressure of 9000 PSIG, an aluminum liner of 0.133 in thickness, and a sizing pressure of 7600 PSIG were found to yield design stress output values within an acceptable range. Of course other liner thicknesses and operating pressures could be utilized.
In the construction of a pressure vessel in accordance with the present invention, formation of the liner is begun by impact extruding a tubular blank with a solid base. The blanks are then solution treated and aged prior to forming. Thereafter, the closed end of the blank is contoured, and the blank is subjected to two neck forming operations, the first in a hot forming die and the second in a cold sizing die. Neck forming in this manner tends to minimize neck wrinkling. The final liner formation steps involve heat treating and machining. As seen in FIG. 5, the liner thickness at the junction of the cylindrical portion with the dome portions will be substantially uniform. The liner throat is fabricated as a threaded section for receiving the threaded portion of the end plug, and suitable sealing rings and washers may be used to further seal the port when the end plug is inserted. After formation of the liner the filament winding operation is performed. Equipment found suitable for use to effect this winding is the Entec Model 430 Filament Winding Machine which is known in the art and which is capable of winding in both the polar oriented and cylindrically oriented directions. During the preferred sequence, the first polar overwrap is effected by the winding of 98 circuits with a 4-roving delivery system comprised of 20 ends per roving about the liner. Next, seven layers of cylindrical material (14 passes with a 4-roving delivery system comprised of 20 ends per roving) are applied, and, of course, the cylindrical material is wound so as to cover the junction of the cylindrical portion with the dome portions. FIG. 3 shows the vessel after the foregoing two portions of the winding sequence.
Next, the remaining polar-oriented material, (147 circuits with a 4-roving delivery system comprised of 20 ends per roving) is then applied in a similar fashion to the original polar wrapping, and has the effect of holding the cylindrical wrapping against movement relative to the vessel. Finally, two layers of cylindrical material (four passes with a 4-roving delivery system comprised of 20 ends per roving) are then applied to a central region of the cylinder. The completely overwrapped vessel is shown in FIG. 4. Of course, the filament material is to be resin coated as it is wound about the liner. This is effected by drawing the filament through a resin filled reservoir just before it is wrapped. Heat curing of the vessel follows the overwrapping steps, and for the vessel whose specifications have been set forth above, the heat curing temperature should not exceed 350°F.
After the vessel has been overwrapped and heat cured, the sizing pressurization step is performed. This is accomplished, for the vessel set forth by the design characteristics determined heretofore, by increasing the vessel pressure to 7600 PSIG at a rate not to exceed 500 PSI per min. and then reducing the vessel pressure to ambient.
During this cycle, when the pressure exceeds the yield strength of the metallic liner, the liner will deform plastically outwardly and tend to retain the enlarged configuration to which the liner was plastically deformed. However, the elastic limit of the filament overwrap will not be exceeded during the pressurization and plastic deformation of the liner. Due to the plastic deformation of the liner, when the liner has elastically unloaded, the filament overwrap is still in tension. Therefore, the filament overwrap applies generally inwardly directed forces to the outer surface of the liner when it reaches the elastically unloaded condition. These inwardly directed oveerwrap forces are effective to compress and elastically deform the liner. However, they are of insufficient magnitude to plastically deform the liner in compression. Therefore, after the sizing pressurization cycle the overwrap filament is stressed in tension and the liner is stressed in compression.
To effect a plastic outward deformation and bursting of the liner after the sizing pressurization cycle, it is necessary to increase the pressure in the liner to a value sufficient to overcome the compression forces in the liner and to effect outward deformation of the liner with a force sufficient to rupture the strong overlap filament. Under normal operating pressures, the pressure forces may be sufficient to overcome the compression forces in the liner. However, the pressure forces will not, during normal use, be of a magnitude sufficient to plastically deform the liner against the influence of the filament overwrap.
It should be noted that while sized pressure vessels in accordance with this invention will exhibit some crazing, the effect of such crazing on vessel performance will be minimal.
A pressure vessel manufactured in the manner set forth above will have particular application in portable breathing systems of the type commonly used by firemen and scuba divers. On the other hand, it will be readily obvious to those of ordinary skill in the art that the foregoing method can be used to manufacture pressure vessels for different types of applications with equally satisfactory results.
Similarly, while the specific preferred embodiment illustrated in the drawings has fibrous overwrapping material of glass, it is contemplated that other fibrous materials, including graphite, boron or Kevlar, may be used. Of course, the specific fibrous materials utilized may vary with variations in the environment in which the pressure vessel is utilized. | A pressure vessel of the type wherein a metallic liner in the shape of a cylindrical portion with a dome-shaped portion at each end thereof is overwrapped by a plurality of layers of resin coated, single fiberglass filaments. A four-step wrapping technique reinforces the vessel with overwrap material at the most likely areas for vessel failure. Overwrapping of the vessel is followed by a sizing pressurization cycle which induces a compressive prestress into the liner and thereby permits the liner to deform elastically through an increased strain range. | 8 |
BACKGROUND OF THE INVENTION
This invention concerns an ultrasonic imaging apparatus operating according to the impulse-echo technique, particularly for medical diagnosis, with an ultrasonic applicator for the linear ultrasonic scanning of a body region and an image registering device with a line generator for the formation of the echo impulses as an image line and an image generator for the displacement of successive image lines in dependence upon the displacement of the ultrasonic beam in the object, wherein the ultrasonic applicator comprises a parabolic reflector and an ultrasonic transducer head arranged for rotation about the focal line of the parabolic reflector, the head having a plurality of ultrasonic transducers which are to be focused on the reflector and which function as transmitters and/or receivers, and wherein an angle of rotation responsive signal generator is assigned to said transducers and in dependence upon the angular movement of the respective active transducer, supplies to the image generator an image line displacement voltage for displacing the successive image lines which initially has a relatively rapid rate of increase, which increases at a slower rate as the active transducer traverses a central region of the reflector, and again provides a more rapid rate of increase toward the end of a traverse of the reflector, in conformity to the variable displacement velocities of the reflected ultrasonic beam at the reflector border zones in comparison to the reflector center zone.
An ultrasonic imaging device with an ultrasonic applicator is prior art from U.S. Pat. No 3,470,868, which exhibits a cylindrical parabolic reflector, in whose focal line is disposed an ultrasonic transmitting/receiving head (with a total of two transmitting/receiving transducers) the head being arranged rotatably about the focal line as axis, and being adjustable along the focal line. During rapid rotation of the ultrasonic head about the focal line, an ultrasonic beam radiated in the direction of the reflector and reflected from the latter into a body which is to be examined, for example, is displaced parallel to itself in the body area, on account of the reflection properties of the reflector. Thus, the reflected ultrasonic beam scans this body area along a rapid succession of lines which are parallel to one another. During the corresponding linear image formation of the echo signals received from a scanning line in the body area, respectively, on a viewing screen of an oscilloscope as the display and/or recording device, a sectional view of the body region to be examined is obtained in the scanning plane. Planes parallel thereto are obtained by means of a corresponding displacement of the ultrasonic transmitting receiving head in the direction along the focal line of the parabolic reflector. However, the prior art ultrasonic imaging device has the following disadvantage. If the rotation of the rotary shaft for the ultrasonic head (employing an electric motor as the rotary drive, for example) takes place with uniform angular velocity, the beam of the respective presently active ultrasonic transmitter/receiver which is reflected by the reflector moves perpendicular to its direction of propagation in the border zones of the parabola with greater velocity (perpendicular to the direction of the parallel-proceeding sound waves) than in the central zone of the parabola. The consequence of this is that the scanning of the area under investigation does not proceed with equal velocity; thus the information density from this area is not uniform, on the one hand, and non-linear distortions occur during image registration on the other hand. Attempts have already been undertaken in order to eliminate these disadvantages at least partially. Thus, for example, in the devices according to U.S. Pat. No. 3,470,868, angle of rotation responsive signal generators have been introduced which at least provide a line displacement voltage at the image generator having the initially described variable rate of rise characteristic for the purpose of correction of non-linear distortions during image registration. However, the modulation of the image line displacement voltage took place by means of an inductive impedance change using a pair of cam plates, which in dependence upon the angular position of the respective assigned ultrasonic transducer, penetrated more or less deeply in the air gap of a high frequency generator. Angle of rotation responsive signal generators of this type are not only extremely complicated and costly from a technical point of view; in addition, accurate reproduction thereof is difficult leading to relatively high manufacturing costs. Moreover, the linearization effect is not optimal on account of the poor reproducibility of the angle responsive generator, and in addition, non-uniform information densities result. The U.S. Pat. No. 3,470,868 describes additional attempts at a solution. However, the paths of solution initiated therein are entirely of a mechanical type; that is, compensation for the non-linear effects, or the non-uniform information densities, respectively, takes place by means of engagement into the drive train of the rotary drive of the ultrasonic head in such a manner that, by means of correspondingly designed cam plates, the original drive with uniform angular velocity is converted into a drive with non-uniform velocity (such that the speed of rotation of the sound head in the region of the border zones of the reflector is slower than in the central one of the reflector). These purely mechanical solutions are also technically too complicated and likewise, as practice has shown, do not compensate for nonlinearities or variable information densities from the area under investigation to the high degree which is actually desirable.
SUMMARY OF THE INVENTION
It is an object of the present invention to construct an ultrasonic imaging device of the type initially referred to such that, with solution means which are technically much less complicated and which at the same time are capable of greatly improved accuracy of reproduction, optimal conditions of linearity are insured on the one hand, and if required, extremely constant information densities are also attainable on the other hand.
As specified by the invention, the problem is solved in that the angle of rotation responsive signal generator comprises a marking system consisting of angle of rotation marks, assigned to the ultrasonic transitting/receiving transducers, the marking system rotating with the transducers and the number of marks being selected to correspond to the desired angular resolution accuracy for the respective transmitting/receiving transducers, and the distances between the marks being wider corresponding to the lower ultrasonic scanning velocity for a given angular increment of rotation of the transducers at the reflector mid region and being narrower corresponding to the higher ultrasonic scanning velocity for corresponding angular increments of rotation with respect to the region of the reflector edges, the marking system further comprising a mark scanner for scanning of the marks during rotation thereof with the transducers and for controlling the rate of image line displacement in dependence upon the rate of scanning of the individually scanned marks, such that the image line displacement takes place rapidly during scanning of a rapid succession of marks, and takes place correspondingly less rapidly during scanning of a less rapid succession of marks.
In contrast to an inductive angle responsive device using cam plates, an angle of rotation responsive signal generator consisting of angle of rotation marks as well as a mark scanner can be more easily constructed and also can be reproduced accurately in mass production. This not only simplifies the technical expenditure; an optimal linearity during image synthesis also results, and with a corresponding adaptation of the ultrasonic impulse repetition rate to the rate of mark scanning by the mark scanner, for example, an extremely uniform information density in the ultrasonic image additionally results.
Other objects, features and advantages of the present invention will be apparent from the following detailed description of an exemplary embodiment, taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic perspective illustration of an ultrasonic applicator incorporating an ultrasonic imaging system according to the present invention;
FIG. 2 is a fragmentary sectional view taken along the line II--II of FIG. 1 and shows an optoelectric mark scanner system cooperating with a rotary mark carrier, and which together form a component part of the angle of rotation responsive signal generator for the ultrasonic imaging system according to the present invention;
FIG. 3 illustrates a basic circuit diagram for the inventive ultrasonic sectional imaging system;
FIG. 4 constitutes a diagram showing the waveform as a function of time of the most important signals occurring in the basic circuit according to FIG. 3;
FIGS. 5 and 6 illustrate modifications of the basic circuit of FIG. 3; and
FIG. 7 is a diagrammatic illustration of a practical exemplary embodiment of the mark carrier for an ultrasonic imaging system in accordance with the present invention.
DETAILED DESCRIPTION
In FIG. 1, reference numeral 1 designates a cylindrical parabolic reflector, in whose focal line 2 an ultrasonic head section 3 is arranged for rotation about the focal line as axis and for longitudinal adjustment along the focal line. The ultrasonic head assembly of FIG. 1 has altogether three ultrasonic transducers 4, 5 and 6, which are arranged about the circumference of the lower head section 3, at angular separations of 120°. Of transducers 4 through 6, only transducers 4 and 6 are visible in the perspective illustration of FIG. 1. However, the actually non-visible third transducer 5 is indicated in dotted outline. Individual transducers 4 through 6, in the activated state, respectively, produce an ultrasonic beam consisting of ultrasonic impulses which are transmitted toward successive points along reflector 1, and which are reflected by the latter, via a non-illustrated water coupling path, for example, into an object which is to be examined. During rapid rotation of ultrasonic head 3, the ultrasonic beam of the respective activated ultrasonic transducer 4, 5 or 6, scans the object along mutually parallel lines, due to the reflection properties of the reflector 1. The echo impulses originating from each ultrasonic scanning line, which are received by the presently active ultrasonic transducer operating as both transmitter and receiver, are finally registered in corresponding linear form on the viewing screen of an oscilloscope tube. Thus, the desired ultrasonic echo sectional view of the object results.
In the present exemplary embodiment, an incremental angle-disk or mark carrier in combination with two optoelectric impulse generators, functions as a significant component part of the angle of rotation responsive signal generator, and simultaneously functions as a control element for the chronologically synchronous switching on-or off of the individual transducers as transmitter and receiver. In FIG. 1, the angle-disk 7 is arranged at the upper side of the ultrasonic head section 3. The disk, which consists of a translucent base material, preferably plexiglas, for example, exhibits on its circumference a plurality of thin black radially directed lines 8 arranged in three angle-sectors of 120° each with intervening heavier black control areas 9, 10 and 11. The angular relationship of disk 7 to ultrasonic transducers 4 through 6 can be such that black segment 9 is located directly above transducer 4, black segment 10 directly above transducer 5, and black segment 11 directly above transducer 6. Black segments or opaque control marks 9, 10 and 11 primarily serve the purpose of marking the beginning of each transmitting/receiving period, respectively, of one of the ultrasonic transducers 4 through 6. The thin black lines 8, on the other hand, mark respective angular increments of movement of the assigned ultrasonic transducer 4, 5 or 6, respectively, in the course of the respective transmitting/receiving interval of the assigned transducer, which angular increments on the whole are to correspond to constantly uniform displacement steps of the ultrasonic scanning beam in the body region under examination. The spacing between the individual lines 8 in each of the three 120° angle sectors which are separated by the respective black segments 9 through 11, is accordingly variable selected such that the line spacing becomes increasingly narrower near each black segment 9, 10, 11, relative to the line spacing in the center portions intermediate such black segments. In the exemplary embodiment according to FIG. 7, for example, each sector between pairs of the black segments 9 through 11 contains approximately 160 thin individual lines, the line spacing in each sector central portion being equal to approximately eight-tenths of a millimeter (0.8 mm), and decreasing continuously in both directions toward the respective adjoining black segments 9-11 to a spacing of approximately five-tenths of a millimeter (0.5 mm). A first optoelectric generator 12 is constructed to be actuated by light interruptions, and serves the purpose of scanning the line segments or marks 8 as well as the black segments or control marks 9 through 11. A second optoelectric generator 13 is likewise constructed to respond to light interruptions and functions in combination with an additional thick black segment 14 on the angle disk 7 which as indicated in FIG. 7 is disposed nearer the center of the disk, the further control mark 14 serving as an additional synchronization element for the purpose of insuring chronologically correct activation of the respective ultrasonic transducers 4, 5 and 6. As is made clearer in the sectional view according to FIG. 2, each optoelectric generator 12 or 12, respectively, comprises a light producer which is to be preferably a light emitting diode in the present illustrated embodiment. A light receiver, for example a photo-conductive cell, is assigned to each of these light producers on the opposite side of the disk. In FIG. 2, the light producer of the optoelectric generator 12 is designated by 15 and the respective light receiver is designated by 16. The light producer of the photoelectric generator 13, in contrast, bears the identifying numeral 17, and the respective light receiver bears the identifying numeral 18. Elements 19 through 22 are support elements for the purpose of mounting the light producers and light receivers respectively of the optoelectric generators 12 and 13.
An electric motor 23 serves as the rotary drive element for the sound head 3 and the angle disk 7 of the applicator as shown in FIGS. 1 and 2, the motor 23 being operatively connected to rotary shaft 25 of sound head 3 via a friction drive or a gear drive 24, for example.
In FIG. 3, which illustrates the entire arrangement of the ultrasonic sectional imaging apparatus in basic construction, the reflector is again designated by reference numeral 1, the ultrasonic head by reference numeral 3, and the three ultrasonic transducers arranged at angles of 120° are designated by reference numerals 4, 5 and 6. The illustration corresponds to a cross-section of ultrasonic head 3 below the angle disk 7. In FIG. 3, of the optoelectric generator devices 12 and 13, only the respective assigned light receivers 16 and 18 are indicated. Ultrasonic transducers 4, 5 and 6 of the basic circuit diagram of FIG. 3 are each capable of being individually connected to a high frequency impulse generator of component 29 via a respective assigned electrically controlled switch 26, 27 or 28. The high frequency impulse generator of component 29 is controlled as to its impulse supply rate by the rate of control pulses supplied thereto by means of impulse generator 30. Switching on of the switches 26, 27 or 28 according to the required schedule takes place via the switching impulse outputs of a ring counter 31. The ring counter 31 is provided with two control inputs the first of which is connected to the light receiver 18 of the optoelectric generator 13 via a signal amplifier 32. The second control input is connected to the output of a first threshold discriminator 33 which receives the electric pulse signals emitted by light receiver 16 as a function of light interruptions at the optoelectric generator 12 as amplified in amplifier 34. In addition, reference numeral 35 designates a second threshold discriminator for the signals from amplifier 34 and this second discriminator is connected at its output side to the counter input of a pulse counter 36. The pulse counter 36 has a switching input 37 connected with the output of the first threshold discriminator 33 which serves to reset the counter 36 to an initial count condition. The counter 36 controls a digital to analog converter 38, and the analog output of converter 38 is supplied to an amplifier 39 which in turn is connected to a pair of horizontal deflection plates 40 of an electron beam tube 41 for the purpose of successively deflecting the electron beam to trace successive image lines as diagrammatically indicated on the face of the tube 41 in FIG. 3. A pair of vertical deflection plates 42 of tube 41, on the other hand, is connected to a line-sweep generator 43 and the latter is in turn connected to the output of control pulse generator 30 in order to control the initiation of successive image line deflection cycles in dependence upon the initiation of successive impulse transmission times of the successive ultrasonic energy impulses to be transmitted by the active transducer. In order to take into consideration preliminary time intervals, for example the ultrasonic transmitting/receiving impulse transmission time in a preliminary water path, an adjustable monostable delay circuit 44 may, if necessary, for example, be placed in a circuit between the control pulse generator 30 and the line-sweep generator 43. The delay circuit 44 may be adjusted so as to provide a delay of a predetermined period of time between the transmitting time for a given ultrasonic beam impulse and the initiation of a line-sweep operation for the purpose of registering the associated echo impulses. Line 45 leading to the control pulse generator 30, or the additional line 46 shown as a dash line in FIG. 3, are control lines for the purpose of controlling the initiation of each control pulse and thus control the pulse frequency of the impulse generator 30, the control line 45 serving to control the rate of control pulse generation in dependence upon the output of the second discriminator 35, and the control line 46 optionally controlling the rate of control pulse generation by component 30 in dependence upon the output of the first discriminator 33. Of course, the control pulse generator 30 may be a free running multivibrator circuit with an adjusted desired output pulse rate if control of the control pulse rate from the mark scanner is considered unnecessary for a particular use of the illustrated embodiment.
The mode of operation of the imaging device according to FIG. 3 will be apparent in connection with FIGS. 1 and 2, as well as when considered with the voltage waveforms shown in FIG. 4. The following description will correlate the waveforms of FIG. 4 with the structure of FIGS. 1-3.
By energizing motor 23, FIG. 1, ultrasonic head 3 together with angle disk 7 is driven at a rapid rotational rate. The rotation of the angle disk 7 in turn has the effect that the light beam of the optoelectric generator 12 is periodically interrupted at the mark scanning rate corresponding to the variable spacing of the opaque lines 8. Thus, the mark signals from generator 12 after amplification in amplifier 34 produce a voltage signal U 1 (t) which has a waveform as a function of time as schematically illustrated at U 1 in FIG. 4. In FIG. 3, amplifier 34 is shown as being connected with the output of light receiver 16 and as supplying at its output the waveform diagrammatically indicated at U 1 in FIG. 4. The voltage waveform U 1 of FIG. 4 is repeated for each revolution of the sound head 3 and the angle disk 7, respectively, and is essentially characterized by a total of three successive trains 47, 48 and 49 of mark impulses of relatively brief duration which are interrupted by longer pulse pauses or control intervals 50, 51 and 52. The longer duration interruption signals or control intervals 50, 51 and 52 originate respectively from the light-interruptions by the opaque control segments 9, 10 and 11 on disk 7. The impulse trains of the brief duration mark impulses are designated by reference numerals 47, 48 and 49 in FIG. 4 and are the result of the light interruptions produced by scanning of the narrow lines 8 of respective 120° segments on the angle disk 7. Since, as previously mentioned, the line spacing in the three 120° segments decreases from a central portion toward the respective adjacent wider black segments 9-11, the mark impulses near the beginning or end of the respective trains 47, 48 and 49 of shorter overall duration and thus occur at shorter intervals than the impulses occurring in the central portions of the impulse trains. The voltage U 1 (t) supplied by amplifier 34 is simultaneously supplied to the first and second threshold discriminators 33 and 35. In accordance with the threshold value indicated by dash line G 1 in FIG. 4, the threshold discriminator 33 operates as a clipper and limits its response to the waveform U 1 of FIG. 4 to values up to the threshold G 1 . Thus, a voltage signal U 2 (t) results at the output of threshold discriminator 33 having a waveform as indicated at U 2 in FIG. 4. The threshold discriminator 35 operates with a minimum amplitude threshold as indicated by the dash line G 2 in FIG. 4 and transmits only voltages which exceed this threshold. Thus, a voltage signal U 3 (t) results as represented by the waveform U 3 of FIG. 4 at the output of threshold discriminator 35. The individual impulses of the input impulse trains 47, 48 and 49 in FIG. 4 (for example the positive-going transitions of waveform U 3 ) are then counted in a digital counter 36 which may operate as a binary counter, for example. The counter stages of counter 36 may be coupled to respect the stages of the digital to analog converter 38 so as to generate an analog image deflection voltage corresponding to the condition of the respective stages of the counter 36. Thus, the output of the converter 38 exhibits the stepped voltage change of a voltage U 4 (t) as indicated at U 4 in FIG. 4. The periodic resetting of counter 36 to its zero count condition at the end of each counting interval takes place each time with the scanning of a black control segment 9, 10 or 11, as sensed by the corresponding light interruption at the optoelectric generator 12. Since this coincides with the trailing (negative-going) edge of the waveform U 2 of FIG. 4, the signal U 2 (t) also serves as a triggering impulse for the purpose of resetting counter 36 via control line 37.
From the waveform as a function of time of the image line displacement signal U 4 (t) as indicated at U 4 in FIG. 4, an image line displacement results on the viewing screen of tube 41 such that the successive image lines are at least approximately all equally spaced as diagrammatically indicated in FIG. 3. In order to provide such substantially equal spacing of the image lines with a constant rate of rotation of the ultrasonic transducers, the rate of image line displacement is relatively rapid at the beginning of an image generating cycle, gradually becomes slower toward the center of the image, and, after crossing the center of the image, correspondingly increases to a relatively rapid rate again toward the end of the image generating cycle. However, this variable image line displacement corresponds to the variation in the ultrasonic scanning velocity within the body region being examined which as described increases as a function of distance from the central zone of the reflector outwardly toward the border zones of the reflector. Thus, the desired linearization effect results in the image representation, and with a corresponding adaptation of the ultrasonic impulse rate by means of a control line such as 45, a good constant information density also results, which small be explained in greater detail in the following. The described mode of operation solely concerns the production of an image deflection of voltage according to the waveform U 4 of FIG. 4. What is still lacking is the direct chronological synchronization between the transmitting-or-receiving-times of each transducer 4, 5, 6 with the image line displacement signal U 4 (t) as represented by waveform U 4 in FIG. 4. In combining both optoelectric generators 12 and 13 with ring counter 31, as well as with switches 26 through 28, this synchronization results for the switching on of the individual transducers 4 through 6, as follows.
In the illustration according to FIG. 1, the light beam of the optoelectric generator 12 impinges on the opaque control mark 11 simultaneously with the impingement of the light beam of the optoelectric generator 13 onto the further opaque control mark 14. As shown in FIG. 1, at this time, transducer 4 which is below the black mark 9 is positioned directly at the entry region of reflector 1. The simultaneous arrival of the control marks 11 and 14 at the mark scanner means has the effect of producing simultaneous interruption impulses at the output of amplifier 32 and at the output of the threshold discriminator 33. The simultaneous arrival of these interruptions and impulses, specifically, in turn, brings about an impulse emission in the ring counter 31 to insure that the ring counter is set to the condition such that switch 26 is closed and transducer 4 activated for the purpose of radiation and reception of ultrasonic signals in association with the impulse generator component 29. The successive interruptions of the light beam of the optoelectric generator 12 by means of the opaque control segments 10 and 9 (for the illustrated direction of rotation of sound head 3) then successively step the ring counter 31 to a second condition where switch 28 is closed and switches 26 and 27 are kept open, and then to a third condition where switch 27 is closed while switches 26 and 28 are kept open. Thus, in the successive first second and third conditions of ring counter 31, first transducer 4, then transducer 6, and finally transducer 5 are activated in synchronism with the rotary movement of the head assembly. This process is repeated periodically with each revolution of the ultrasonic head 3 and correct synchronism is insured by the renewed coincidence of the interruption impulses produced by control marks 11 and 14 in each such revolution.
In the exemplary embodiment according to FIG. 3, there are various possibilities regarding the selection of the image line displacement frequency. Since, as stipulated, each impulse of the optoelectric generator 12 corresponds to a step of the deflection beam (in the horizontal direction as viewed in FIG. 3) on the image tube 41 by a substantially constant value, the number of impulses on each of the trains 47, 48 and 49 in FIG. 4 may now be selected so as to be equal to the number of desired image lines to be produced on the registration device 41. With this selection, the impulse sequence U 3 (t) at the output of the threshold discriminator 35 may be utilized directly for the purpose of triggering the control pulse generator 30 for the emission of corresponding trigger pulses for actuating the high frequency generator 29, such that the impulses from the component 29 are directly synchronized with the pulses of the waveform U 3 of FIG. 4. In this case, a number of lines results which corresponds to the number of lines on the angle disk 7 between two successive opaque control segments, the resulting image lines on the registration device such as indicative at 41 having a line spacing which is always exactly constant, and thus also having a constant information density, independent of any fluctuations in the drive system for the transducer head 3 whatsoever. It is just as possible, however, to synchronize the control pulses from the impulse generator 30 only with the impulses of the impulse sequence U 2 (t) (for example, via the control line 46 indicated by dash lines in FIG. 3), and otherwise to permit the control pulse generator 30 to run freely with a preselectable repetition frequency. In this case, for example, the light interruption intervals of the waveform U 2 could be utilized to block the transmission of ultrasonic pulses from component 29 during the image retrace interval of the registration device such as 41, the higher amplitude levels of the waveform U 2 then corresponding to the transmission of a succession of control pulses from component 30 each operable to trigger an impule of high frequency energy from component 29. By way of example, the control pulse repetition frequency supplied by component 30 may be selected to correspond approximately to the foregoing line scanning frequency of optoelectric generator 12. The possibility also offers itself here that, by means of a corresponding frequency multiplication, for example by doubling the pulse waveform U 3 of FIG. 4 in a frequency doubling element 53 as shown in FIG. 5, the impulses of the impulse sequence U 3 (t) may be converted to a waveform U' 3 of twice the number of pulses of the waveform U 3 of FIG. 4. By such frequency multiplication, a waveform U' 4 can be produced with constant voltage steps, but with such voltage steps reduced to a fraction of the voltage steps represented for the waveform U 4 in FIG. 4. Such a reduction in the magnitude of the voltage steps for a waveform U' 4 correspondingly automatically leads to a decrease in the danger of a fluctuation between successive image line positions in the generation of an ultrasonic image.
As a further modification, the control pulse sequence from the control generator 30, that is the transmission impulse sequence of the respective active ultrasonic transmitter, may be frequency modulated with a modulating voltage which is obtained, for example, by means of electrical differentiation of the image deflection voltage U 4 (t) as represented by waveform U 4 in FIG. 4. This possibility is indicated in the circuit modification according to FIG. 6, where the electrical differentiating element is designated by reference numeral 54 and is indicated as receiving a variable rate deflection voltage U 4 (t) having a waveform as indicated in the figure and which may be identical to the waveform U 4 of FIG. 4. From voltage U 4 (t, a modulating voltage signal U 5 (t) results which may have a waveform U 5 as illustrated in FIG. 6. The voltage gradient U 5 (t) effects a frequency modulation of the pulse repetition frequency of control pulse generator 30' in such a manner that the control frequency is increased with increasing voltage U 5 (t) and is correspondingly decreased with a dropping of voltage amplitude of the voltage waveform U 5 of FIG. 6. By this means, specifically, particularly uniform information densities in the ultrasonic image result with a random ultrasonic scanning frequency.
In the exemplary embodiment of FIG. 1, the angle disk 7 is shown situated directly on the rotating ultrasonic head. However, it may of course also be arranged on a separate drive shaft, and may be located in a motor drive compartment which is sealed off from the compartment containing the ultrasonic transducers 4-6 and the parabolic reflector 1. Further, the angle disk 7 may have a separate drive shaft which is driven by the sound head shaft 25 with a one to three transmission ratio, for example (as a consequence of the use of a total of three ultrasonic transmitter/receiver elements staggered at 120° intervals). In such an instance, an angle disk is sufficient which exhibits only one single wide control mark segment for the purpose of marking the beginning of each marking pulse train, and in which the narrow lines, corresponding to the desired angular resolution, are not located within three sectors, but are distributed over the entire disk circumference which then rotates at three times the rate of the transducer head 3.
In addition, the exemplary embodiment preferbly operates with a total of three ultrasonic transducers, staggered at 120° intervals. Practice has demonstrated that optimal linearization conditions result hereby in connection with the invention, in view of the least possible expenditure of resources as well as the best image frequency conditions and image resolution conditions. The use of a number of transducer elements which is less than three or greater than three is, indeed, certainly provided within the framework of the invention. However, such embodiments involving a lesser number of transducers would impair the image quality, while embodiments with a greater number of transducers would increase the technical expenditure.
While there have been disclosed exemplary embodiments representing presently preferred practice of the claimed invention, it will be apparent that many modifications and variations may be effected without departing from the scope of the novel teachings and concepts of the present invention. | An ultrasonic applicator including a parabolic reflector for reflecting ultrasonic beam energy for ultrasonic sectional scanning particularly for medical diagnostic purposes, has its image registering system compensated for the variable sweep velocity of the ultrasonic beam energy within the body region under examination by the provision of a rotary mark carrier with a series of angularly offset marks of variable spacing such that as the mark carrier rotates at a constant rate in synchronism with the rotary ultrasonic transducer head, the marks are scanned at a relatively rapid rate as the ultrasonic impulses are reflected at the border regions of the parabola and are scanned at a progressively slower rate during transducing via points progressively closer to the central region of the parabola. | 3 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] This invention relates to a wallet and more particularly to a wallet for carrying a tool adjacent to credit cards, money, business cards and the like.
[0006] 2. The Prior Art
[0007] Many individuals carry both a wallet and a tool as personal effects.
[0008] A common method for carrying a tool is to carry it in a sheath on a waist belt. This proved to be unsatisfactory because the sheath would get caught on seat belts and other things that come in contact with the waist. Also, the sheath does not conceal well and distracts from professional attire.
[0009] Another common method for carrying a tool is to carry the tool in front or rear pants pocket. This proved to be unsatisfactory because the tool can shift locations in the pocket creating discomfort while sitting. Carrying the tool next to the wallet in a pants pocket also proved to be unsatisfactory because the tool and wallet can shift locations, become stacked upon each other and create discomfort.
[0010] A more recent approach is shown in U.S. Pat. No. 5,778,954 issued Jul. 14, 1998 to Sullivan and Jessup. In Sullivan and Jessup's wallet the user is given a means for carrying both a wallet and a tool, and in this case the tool is a knife.
[0011] This wallet is not entirely satisfactory for the following reasons. The tool is kept in one of a plurality of layers of the wallet. The tool adds undue thickness to the wallet. This additional thickness creates discomfort while sitting or standing in the front or rear pants pocket.
[0012] With this in mind the inventor set out to create a better wallet.
BRIEF SUMMARY OF THE INVENTION
[0013] It occurred to the present inventor that it would be more comfortable to carry a tool adjacent to a wallet while not allowing the tool to overlap with the wallet. Thus in accordance with the present invention, the tool is kept in a pocket adjacent to the wallet, not allowing the tool to overlap other sections of the wallet.
[0014] The present inventor also was conscious of the fact that if the device were to be functional it would need elements found in a standard wallet such as pockets to carry credit cards and money.
[0015] Thus it is the object of the present invention to provide a wallet that carries both a tool and items normally found in a wallet while not adding additional thickness to the wallet, therefore minimizing any discomfort from the use of said wallet.
[0016] The novel features which are believed to be characteristic of the invention, both as to its structure and method of use, together with further objects and advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which a preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0017] [0017]FIG. 1 is a front perspective view of a preferred embodiment of the device of the present invention in use; and,
[0018] [0018]FIG. 2 is a front perspective view of a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The combination wallet and tool holder 10 can best be understood by a study of FIGS. 1 and 2 along with the following description. The combination wallet and tool holder allows a human to carry in a conventional pants pocket a tool 12 adjacent to credit cards 34 , business cards 30 , and money 32 while not overlapping said items.
[0020] The combination wallet and tool holder 10 has an elongated pocket 14 , which frictionally holds a tool 12 . The elongated pocket 14 , has an opening 16 and a bottom 20 . The tool 12 can be frictionally inserted or removed from the elongated pocket 14 . The combination wallet and tool holder 10 has rectangular pockets 22 and 24 which hold credit cards 34 , business cards 30 , money 32 , and the like. The rectangular pockets 22 and 24 have openings 26 and 28 to facilitate in the insertion and removal of credit cards 34 , business cards 30 , and money 32 . The combination wallet and tool holder 10 can be closed and prepared for insertion into a pants pocket or other carrier by folding along a score line 18 .
[0021] The combination wallet and tool holder 10 is made from durable material such as leather, plastics, fabrics, canvas, or the like. It is sewn together using nylon thread or the like.
[0022] To use the combination wallet and tool holder 10 a human would insert credit cards 34 , business cards 30 , and money 32 in to the rectangular pockets 22 and 24 . Also, a human would insert a tool 12 into the elongated pocket 14 . The tool 12 is a pocket tool with at least one knife blade. The human would then fold the combination wallet and tool holder 10 along the score line 18 and insert the combination wallet and tool holder 10 into a front or rear pants pocket or other carrier. This action would allow a human to carry a tool 12 adjacent and coplanar to the standard contents of a wallet without adding appreciable thickness to the previous wallet's dimension.
[0023] The foregoing detailed description is illustrative of one embodiment of the invention, and it is to be understood that additional embodiments thereof will be obvious to those skilled in the art. The embodiments described herein together with those additional embodiments are considered to be within the scope of the invention. | A combination wallet and tool holder which carries wallet contents including credit cards, identification cards, business cards, and money adjacent to a tool preventing the overlapping of the tool and the wallet contents. | 0 |
[0001] This application claims priority to prior Japanese application JP 2002-2360766, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a swash-plate compressor for use in, for example, a refrigerating circuit of an automotive air conditioner.
[0003] A swash-plate compressor of the type comprises a compressor body or a cylinder block having a plurality of cylinder bores spaced from one another in a circumferential direction, a plurality of pistons reciprocally movable in the cylinder bores, respectively, a swash plate slidably engaged with one ends of the pistons, and a drive shaft for rotating the swash plate. The drive shaft has one end to which a pulley is attached. By transmitting an external drive force to the pulley, the drive shaft is rotated.
[0004] Each piston has one end provided with a pair of engaging portions faced to each other with the swash plate interposed therebetween, and a side wall portion connecting the engaging portions to each other. Between the engaging portions and the swash plate, a pair of semispherical shoes which serve as sliding members slidably contacted with the swash plate are interposed, respectively. Each of the engaging portions is provided with a contact surface to be slidably contacted with a spherical surface portion of the shoe. The side wall portion of the piston is provided with a recessed portion receiving a peripheral portion of the shoe in a non-contact manner.
[0005] In an automotive air conditioner, a carbon dioxide refrigerant is increasingly used in a refrigerating circuit instead of a chlorofluorocarbon refrigerant in view of environment protection. A compressor adapted to be used with the carbon dioxide refrigerant is disclosed, for example, in Japanese Patent Application Publication No. 2002-31047 (JP-A).
[0006] As compared with the case where the chlorofluorocarbon refrigerant is used, the discharge volume of the compressor is reduced down to ⅙ to ⅛ when the carbon dioxide refrigerant is used. Therefore, the piston having a small outer diameter is used. On the other hand, the working pressure is increased to about 10 times and the load imposed upon the swash plate by the piston is increased by about 20-30%. Therefore, the shoe having a large outer diameter must be used so as to accommodate such a large load from the piston.
[0007] However, use of the shoe large in outer diameter generally requires the side wall portion of the piston to be enlarged outward, resulting in an increase in size of the compressor. Alternatively, the above-mentioned recessed portion may be reduced in thickness and increased in depth without enlarging the side wall portion. In this event, however, the strength of the piston is decreased.
[0008] When the tilting angle of the swash plate is increased with the piston reaching a top dead center or a bottom dead center, the displacement of each shoe is also increased in a radial direction of the piston in the manner known in the art. Sometimes, a part of the spherical portion of each shoe may move out of the contact surface of the engaging portion. In this event, the contact area between the spherical portion of the shoe and the contact surface of the engaging portion is reduced. Such reduction in contact area results in an abnormal sliding condition of the shoe. For example, smooth sliding movement between the shoe and the engaging portion is interfered or inhibited. Sometimes, the shoe may be released and dropped from its position between the swash plate and the engaging portion.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the present invention to provide a swash-plate compressor which is capable of increasing an outer diameter of a sliding member without causing an increase in size of the compressor and a decrease in strength of a piston and which is capable of reliably preventing the sliding member from sliding in an abnormal sliding condition or from being released.
[0010] Other objects of the present invention will become clear as the description proceeds.
[0011] According to an aspect of the present invention, there is provided a swash-plate compressor for compressing a fluid. The compressor comprises a cylinder block having a cylinder bore, a piston having a first end portion reciprocally movable in the cylinder bore and a second end portion opposite to the first end portion, the second end portion having a pair of engaging portions faced to each other with a space left therebetween and a side wall portion connecting the engaging portions to each other, a swash plate having a part inserted between the engaging portions and driven to rotate, and a pair of sliding members interposed between the engaging portions and the swash plate, respectively. Each of the sliding members having a flat portion slidably contacted with the swash plate and a spherical portion opposite to the flat portion. Each of the engaging portions having a contact surface slidably contacted with the spherical portion. Each of the contact surfaces extending to the side wall portion.
BRIEF DESCRIPTION OF THE DRAWING
[0012] [0012]FIG. 1 is a vertical sectional view of a swash-plate compressor according to one embodiment of the present invention;
[0013] [0013]FIG. 2 is a front view of a piston used in the swash-plate compressor illustrated in FIG. 1;
[0014] [0014]FIG. 3 is a side view of the piston illustrated in FIG. 2;
[0015] [0015]FIG. 4 is a sectional view showing the relationship between the piston and shoes;
[0016] [0016]FIG. 5 is a sectional view for describing the force acting between the piston and the shoes illustrated in FIG. 4;
[0017] [0017]FIG. 6 is a sectional view of a piston as a comparative example;
[0018] [0018]FIG. 7 is a sectional view for describing the force acting between the piston and shoes illustrated in FIG. 6;
[0019] [0019]FIG. 8 is a front view of a modification of the piston according to this invention; and
[0020] [0020]FIG. 9 is a front view of another modification of the piston according to this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Referring to FIGS. 1 through 4, description will be made of a swash-plate compressor according to an embodiment of the present invention.
[0022] The swash-plate compressor illustrated in FIG. 1 is used, for example, in a refrigerating circuit of an automotive air conditioner and is adapted to compress a carbon dioxide refrigerant. The swash-plate compressor is of a so-called single-head piston type and includes a compressor body 1 having a cylinder block. The compressor body 1 has one end provided with a plurality of cylinder bores 2 spaced from one another in a circumferential direction. Each of the cylinder bores 2 receives one end of a piston 10 inserted therein to be reciprocally movable. The piston 10 has a small outer diameter and intended to be used with the carbon dioxide refrigerant.
[0023] As well known, a cylinder head 4 is attached to one end face of the compressor body 1 through a valve assembly 3 . The cylinder head 4 has a discharge chamber 4 a formed at its center and a suction chamber 4 b formed around the discharge chamber 4 a . Each of the discharge chamber 4 a and the suction chamber 4 b is communicable with the cylinder bores 2 through valves contained in the valve assembly 3 . Furthermore, the discharge chamber 4 a and the suction 4 b are connected to opposite ends of the refrigerating circuit (not shown), respectively.
[0024] The swash-plate compressor illustrated in the figure further comprises a rotatable drive shaft 5 . The drive shaft 5 has one end to which a pulley 6 is mounted. In order to engage and disengage the pulley 6 and the drive shaft 5 , an electromagnetic clutch 8 is provided. By supplying the pulley 6 with an external drive force and exciting the electromagnetic clutch 8 , the drive shaft 5 is rotated.
[0025] In a crank chamber 1 a formed inside the compressor body 1 , a swash plate 11 is connected through a hinge 7 a to a rotor 7 rotating integrally with the drive shaft 5 . As a consequence, the swash plate 11 is tiltable with respect to the drive shaft 5 and rotatable together with the drive shaft 5 . The swash plate 11 is urged towards each piston 10 by a coil spring 7 b wound around the drive shaft 5 .
[0026] The piston 10 has the other end with which a peripheral portion of the swash plate 11 is slidably engaged in a structure which will presently be described. Each piston 10 has one end provided with a pair of engaging portions 10 a and 10 b faced to each other with the swash plate 11 interposed therebetween, and a side wall portion 10 c extending from one side end of one engaging portion 10 a to one side end of the other engaging portion 10 b . The engaging portions 10 a and 10 b and the side wall portion 10 c are integrally formed. Between the engaging portions 10 a and 10 b and the swash plate 11 , a pair of shoes 12 are interposed, respectively. The shoes 12 serve as sliding members slidably contacted with the swash plate 11 . Each of the shoes 12 has a spherical portion 12 a and a flat portion 12 b opposite to the spherical portion 12 a and slidably contacted with the swash plate 11 .
[0027] The piston 10 has a contact surface 14 extending over the engaging portions 10 a and 10 b and the side wall portion 10 c to be slidably contacted with the spherical portions 12 a of the shoes 12 . In other words, the contact surface 14 is continuously formed from the one engaging portion 10 a through the side wall portion 10 c to the other engaging portion 10 b . It may be understood that the contact surface 14 is extensively formed on each of the engaging portions 10 a and 10 b and the side wall portion 10 c and that these contact surfaces 14 are connected to one another. The contact surface 14 is formed along a spherical surface having a curvature equal to that of the spherical portion 12 a of each shoe 12 . The swash plate 11 is adapted to accommodate a large load owing to the use of the carbon dioxide refrigerant. For example, the swash plate 11 has a sufficiently large thickness.
[0028] When the drive shaft 5 is rotated by the drive force supplied to the pulley 6 , the swash plate 11 is rotated together with the drive shaft 5 . Owing to the inclination of the swash plate 11 , each piston 10 reciprocally moves in an axial direction. When the piston 10 reciprocally moves, the carbon dioxide refrigerant circulates through a refrigerating circuit. Specifically, the carbon dioxide refrigerant is sucked from the refrigerating circuit through the suction chamber 4 b into the cylinder bores 2 and is discharged through the discharge chamber 4 a to the refrigerating circuit. Due to a pressure difference between the suction chamber 4 b and the crank chamber la, each piston 10 is applied with a pressure on its rear side (on the side of the crank chamber 1 a ). Depending upon the above-mentioned pressure, the tilting angle of the swash plate 11 is changed so that the discharge volume by the piston 10 is varied. The cylinder head 4 is provided with a pressure adjusting mechanism 15 for adjusting the pressure difference between the suction chamber 4 b and the crank chamber 1 a.
[0029] When the piston 10 is driven, the swash plate 11 slides along the flat portion 12 b of each shoe 12 in contact therewith. Simultaneously, each shoe 12 slides along the contact surface 14 with the spherical portion 12 a kept in contact with the contact surface 14 . If the tilting angle of the swash plate 11 is increased, for example, when the piston 10 reaches a top dead center or a bottom dead center, the displacement of each shoe 12 is increased. However, since the contact surface 14 is continuously formed over the engaging portions 10 a and 10 b and the side wall portion 10 c , the spherical portion 12 a slides along the contact surface 14 continuously in contact therewith even if the shoe 12 is displaced towards the side wall portion 10 c as illustrated in FIG. 4. Therefore, even if a shoe 12 ′ greater in outer diameter is used as depicted by a dash-and-dot line in the figure, an increase in diameter of the shoe 12 ′ results in an increase in contact area between the spherical portion 12 a and the contact surface 14 and does not require any modification in shape and size of the contact surface 14 .
[0030] Referring to FIG. 5, when the shoe 12 is displaced towards the side wall portion 10 c , the contact area between the spherical portion 12 a of the shoe 12 and the contact surface 14 is not reduced. Therefore, as depicted by arrows in the figure, reactive force applied from the contact surface 14 upon the shoe 12 is uniformly distributed throughout a whole of the spherical portion 12 a.
[0031] Next referring to FIG. 6, a piston 13 in a comparative example has engaging portions 13 a and 13 b and a side wall portion 13 c between the engaging portions 13 a and 13 b . Each of the engaging portions 13 a and 13 b is provided with a contact surface 13 d . On the other hand, the side wall portion 13 c is provided with a recessed portion 13 e receiving a lateral side of the shoe 12 in a non-contact manner. In case where the shoe 12 ′ having a greater diameter is used as depicted by a dash-and-dot line in the figure, the recessed portion 13 e will interfere with the lateral side of the shoe 12 ′ unless the depth of the recessed portion 13 e is increased. In order to avoid such interference, the depth of the recessed portion 13 e must be increased. For this purpose, the side wall portion 13 c is enlarged outward in a lateral direction of the piston 13 . Disadvantageously, this results in an increase in size of the compressor body 1 . Alternatively, the depth of the recessed portion 13 e can be increased by reducing the thickness of the side wall portion 13 c without enlarging the side wall portion 13 c outward in the lateral direction of the piston 13 . In this event, however, the strength of the piston 13 is decreased.
[0032] Referring to FIG. 7, consideration will be made about the force acting between the shoe 12 and the contact surface 13 d in case where the side wall portion 13 c is provided with the recessed portion 13 e receiving the lateral side of the shoe 12 . In this case, a part of the spherical portion 12 a of the shoe 12 displaced towards the side wall portion 13 c moves out of the contact surface 13 d of each of the engaging portions 13 a and 13 b . Therefore, the contact area between the spherical portion 12 a of the shoe 12 and the contact surface 13 d is reduced. As a consequence, reactive force applied from the contact surface 13 d upon the shoe 12 is concentrated to a part of the spherical portion 12 a as depicted by arrows in the figure. This may result in an abnormal sliding condition of the shoe 12 or a release of the shoe 12 from the piston 13 .
[0033] As compared with the comparative example mentioned above, the swash-plate compressor illustrated in FIG. 1 has a structure in which the contact surface 14 is continuously formed over the engaging portions 10 a and 10 b and the side wall portion 10 c . With this structure, even if the shoe 12 is displaced towards the side wall portion 10 c , the spherical portion 12 a of the shoe 12 is continuously kept in contact with the contact surface 14 . Therefore, even if the shoe 12 ′ having a greater outer diameter is used, it is unnecessary to modify the shape or the size of the contact surface 14 . In addition, it is unnecessary to enlarge the side wall portion 10 c outward in the lateral direction of the piston 10 and to reduce the thickness of the side wall portion 10 c . Thus, it is possible to avoid an increase in size of the compressor body 1 and a decrease in strength of the piston 10 .
[0034] Even if the shoe 12 is displaced towards the side wall portion 10 c , the reactive force from the contact surface 14 can uniformly be received by a whole of the spherical portion 12 a . Therefore, even if the tilting angle of the swash plate 11 is large, the shoe 12 can continuously smoothly slide along the contact surface 14 . Accordingly, it is possible to reliably prevent an abnormal sliding condition and a release of the shoe 12 from the piston 10 and to distribute the reactive force from the contact surface 14 so that occurrence of local wear is avoided. Thus, the above-mentioned structure of this invention is advantageous also in view of improvement of the durability.
[0035] Furthermore, the contact surface 14 is continuously formed over the engaging portions 10 a and 10 b and the side wall portion 10 c . Therefore, it is possible to accommodate not only an increase in diameter of each shoe 12 but also an increase in sliding range of each shoe 12 . Thus, the versatility can be improved. In this case, since the contact surface 14 is formed on the side wall portion 10 c by cutting, the piston 10 can be reduced in weight. This structure is advantageous if it is desired to reduce the inertial force. Because the contact surface 14 is continuously formed between the engaging portions 10 a and 10 b , a lubricating oil 15 can be retained on the contact surface 14 between the shoes 12 as illustrated in FIG. 5. Thus, it is possible to reliably supply the lubricating oil 15 to each shoe 12 . As a consequence, each shoe 12 can very effectively be prevented from seizure.
[0036] Furthermore, it is possible to easily produce the contact surface 14 continuously formed. In this case, the contact surface 14 is formed along a spherical surface having a curvature equal to that of the spherical portion 12 a of each shoe 12 . Therefore, the contact surface 14 can be easily formed by cutting or the like so that the productivity is improved.
[0037] Furthermore, the durability can be improved without causing an increase in size of the compressor body 1 and a decrease in strength of the piston 10 as described above. Therefore, it is possible to use the carbon dioxide refrigerant high in working pressure. Thus, by the use of the carbon dioxide refrigerant, it is possible to achieve the refrigerating circuit advantageous in environment protection. Particularly when the compressor is used in the automotive air conditioner, the structure of this invention is very effective.
[0038] As illustrated in FIG. 8, the contact surface 14 may be formed continuously from each of the engaging portions 10 a and 10 b to a part of the side wall portion 10 c.
[0039] As illustrated in FIG. 9, the contact surface 14 may be divided by a groove 10 e.
[0040] By forming an integral member corresponding to a combination of the swash plate 11 and the rotor 7 , it is possible to provide a fixed-volume or fixed- displacement compressor comprising a swash plate having a predetermined fixed tilting angle with respect to the drive shaft 5 . In such a compressor, this invention can similarly be embodied to achieve the similar effect.
[0041] Although the present invention has been shown and described in conjunction with a few preferred embodiments thereof, it should be understood by those skilled in the art that the present invention is not limited to the foregoing description but may be changed and modified in various other manners without departing from the spirit and scope of the present invention as set forth in the appended claims. For example, the present invention is not limited to a compressor of a single-head piston type but is applicable to a swash-plate compressor using a double-head piston. | In a swash-plate compressor for compressing a fluid, the compressor includes a cylinder block having a cylinder bore and a piston having a first end portion reciprocally movable in the cylinder bore and a second end portion opposite to the first end portion. The second end portion has a pair of engaging portions faced to each other with a space left therebetween and a side wall portion connecting the engaging portions to each other. The compressor further includes a swash plate having a part inserted between the engaging portions and driven to rotate and a pair of sliding members interposed between the engaging portions and the swash plate, respectively. Each of the sliding members has a flat portion slidably contacted with the swash plate and a spherical portion opposite to the flat portion. Each of the engaging portions has a contact surface slidably contacted with the spherical portion. Each of the contact surfaces extends to the side wall portion. | 5 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates generally to computer architectures and, more particularly, to a method and an apparatus for shifting an operand a specified direction and amount.
[0003] 2. Description of Related Art
[0004] Computer processors are constantly being designed with additional capabilities. In particular, some processors, such as the PowerPC designed by IBM Corp., Apple Computers Corp., and Motorola, Inc., are being modified to provide multimedia extensions, such as the Vector Multimedia Extension (VMX). Some extensions such as a shift instruction, however, require additional processing and, therefore, may not be as efficient as desired.
[0005] Shift instructions frequently utilize multiple operands to specify the desired action. A first operand typically specifies the operand that is to be shifted left or right, a second operand typically specifies the amount that the first operand is to be shifted, and a third operand typically specifies the location to place the result. Additional, or fewer, operands may be present depending on the implementation.
[0006] Generally, the second operand that specifies the amount must be decoded to extract the necessary information and to format the information appropriately. The process of decoding the second operand, however, is processing-intensive and requires additional space.
[0007] Therefore, there is a need to provide a method and an apparatus for efficiently shifting a value a specified amount and direction.
SUMMARY
[0008] The present invention provides a method and an apparatus for performing a shift operation on an operand. The method and apparatus configures an input line comprising a first part that includes the bits in order representing various shift amounts in a first direction and a second part that includes bits ordered representing various shift amounts in a second direction. The shift amount is then utilized to index into the input line and select the appropriate bits to create the result.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:
[0010] [0010]FIG. 1 is a schematic diagram of a typical circuit that embodies the present invention;
[0011] [0011]FIG. 2 is a schematic diagram of a circuit that illustrates one embodiment of the present invention that shifts an operand a specified direction and amount; and
[0012] [0012]FIG. 3 is a data flow diagram illustrating one embodiment of the present invention in which an operand is shifted a specified direction and amount.
DETAILED DESCRIPTION
[0013] In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, it will be obvious to those skilled in the art that the present invention may be practiced without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present invention in unnecessary detail. Additionally, for the most part, details concerning operation and the connectivity of the individual components of the present invention, and the like, have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the skills of persons of ordinary skill in the relevant art.
[0014] It is further noted that, unless indicated otherwise, all functions described herein may be performed in either hardware or software, or some combination thereof. In a preferred embodiment, however, the functions are implemented in hardware in order to provide the most efficient implementation. Alternatively, the functions may be performed by a processor such as a computer or an electronic data processor in accordance with code such as computer program code, software, and/or integrated circuits that are coded to perform such functions, unless indicated otherwise.
[0015] Referring to FIG. 1 of the drawings, the reference numeral 100 generally designates a circuit, which may be particularly useful in performing a vector shift instruction, such as a Vector Shift Left Octet (vslo), a Vector Shift Right Octet (vsro), and/or the like, of the Vector Multimedia Extension (VMX) standard for the PowerPC designed and developed by Apple Computers, Inc., IBM, Corp., and Motorola, Inc., embodying features of the present invention. The circuit 100 is exemplified herein as coexisting with another circuit, in this case a crossbar, commonly referred to as an XBAR function, that is capable of implementing many vector permute operations, such as vector packs, unpacks, merges, splats, and vector shift left double instructions, or the like, to demonstrate that additional efficiencies may be achieved by implementing the circuit 100 in conjunction with another compatible circuit. The circuit 100 may, however, be implemented with other types of circuits or individually. Furthermore, the discussion that follows and FIGS. 2 and 3 illustrate the present invention in terms of a 128-bit shift instruction for purposes of illustration only and should not be construed so as to limit the present invention in any manner. For example, the circuit 100 could be used with other types of circuits, individually, other bit lengths such as 64, 256, or the like, and the like, and is considered to be obvious to a person of ordinary skill in the art upon a reading of the present disclosure.
[0016] The circuit 100 generally comprises a decoder 110 configured for receiving and decoding an instruction 112 . Generally, an instruction has the following format:
[0017] operation VT,VA,VB
[0018] where:
[0019] operation is the requested action, such as vslo, vsro, or the like;
[0020] VT specifies the destination of the output;
[0021] VA specifies the operand to be shifted; and
[0022] VB specifies the operand that contains the shift amount.
[0023] The VA and VB operands may typically be any allowable data source (not shown), such as register files, bypasses, data forwarding, load ports, and/or the like, that is selectable via a mux (not shown). In FIG. 1, VA net 114 and VB net 126 represent the VA and VB operands, respectively, that are preferably sourced via mux from one or more data sources.
[0024] Preferably, one or more bits of the operand specifying the shift amount, e.g., bits 121 - 124 of VB net 126 of a vslo and a vsro instruction, are coupled to a mux 128 . The select line of the mux 128 is controlled by the decoder 110 , which selects the shift amount bits and shift direction when the decoder determines that the instruction 112 is a vslo or vsro instruction. The mux 128 is configured to latch the shift amount from the VB net 126 , and an indication of the shift direction from the decoder, referred to as the VC operand 130 , to the shifter 122 and the crossbar 124 . In the preferred embodiment, the VC operand 130 is configured as 16 byte slices (16 byte slices times 8 bits/byte is 128 total bits). The shift direction is preferably specified in bit 3 , which is from the decoder 110 , and the shift amount, which is from bits of the VB net 126 , is preferably specified in bits 4 - 7 of each byte slice, bits 0 - 2 being unused. The shift direction is preferably set to a “ 0 ” to indicate a left shift and to a “ 1 ” to indicate a right shift. As will be appreciated by one skilled in the art, each byte slice contains the same value and will be in the range of 0-31, with 0-15 indicating a left shift of 0-15 bytes and 16-31 indicating a right shift of 0-15 bytes.
[0025] VB net 126 is also coupled to a mux 132 , whose select line is controlled by the decoder 110 . The mux 132 is configured to allow the decoder 110 to select between the sourced operand, i.e., VB net 126 , or a constant zero value. In the event that the decoder 110 determines that the instruction 112 is a shift instruction, such as vslo, vsro, or the like, the decoder 110 sets the select line of the mux 132 such that the zero constant value is latched as a VB operand 134 to the shifter 122 and crossbar 124 .
[0026] It should be noted that the circuit 100 assumes that the shift instructions shifts the VA operand 120 left or right and fills the vacated positions with zeroes. Implementing other types of shifts, such as a circular shift, a signed shift, and/or the like, may be designed similarly and is considered obvious to a person of ordinary skill in the art upon a reading of the present disclosure.
[0027] The shifter 122 and the crossbar 124 is configured to provide a shifter output 136 and an crossbar output 138 , respectively, preferably to a mux 140 , which is used to select the output of one or more circuits, based on the instruction 112 . Accordingly, the shifter output 136 is chosen for vslo and vsro instructions, and the crossbar output 138 or any other output done in parallel with the shifter and crossbar are chosen for all other instructions. Alternatively, data forwarding (not shown) may be enabled in order to obtain greater efficiencies.
[0028] [0028]FIG. 2 is a schematic diagram depicting a circuit that may be designed to perform operations of the shifter 122 (FIG. 1) in accordance with one embodiment of the present invention that receives a 128-bit VA operand 120 (FIG. 1) to shift, a 128-bit VB (zero filled) operand 134 (FIG. 1), and a VC operand 130 (FIG. 1) that specifies the shift direction and the shift amount as discussed above. Accordingly, VA(x 1 -x 2 ) represents a byte corresponding to the x 1 th bit to the x 2 th bit of the VA operand 120 , VB(y 1 -y 2 ) represents a byte corresponding to the y 1 th bit to the y 2 th bit of the VB operand 134 , and VC(z 1 -z 2 ) represents the z 1 th bit to the z 2 th bit of the VC operand 130 . As noted above, the illustrated shifter is a byte shifter. Shifters of other amounts, such as words or bits, may be designed and are considered to be within the skills of a person of ordinary skill in the art upon a reading of the present disclosure.
[0029] As will be appreciated by one skilled in the art, the bits contained in each byte slice of the VC operand 130 that specify the shift direction and the shift amount, are used as a single 5-bit value ranging from 0-31. The 5-bit value is used as the select line of muxes 210 to select the corresponding byte of the designated input lines, forming the dout lines. The connection of the bits of the VA operand 120 and the VB operand 134 as shown shifts the VA operand to the left or right from 0 to 15 bytes, as specified by the 5-bit value.
[0030] For example, a vslo shift instruction with a shift value of 1 results in a VC operand 130 with each byte slice containing a “xxx00001” (binary), and, therefore, each select line of the muxes 210 are set to “1” (hex). As a result, the byte corresponding to the second mux data line (the first mux data line representing a shift of zero) is selected: dout(0-7)=VA(8-15), dout(8-15)=VA(16-23), . . . , dout(120-127)=VB(0-7). This equates to a shift left by one byte, bringing in one byte from VB, which contains all zeros.
[0031] For another example, a vsro shift instruction with a shift value of 15 results in a VC operand 130 with each byte slice containing “xxx11111” (binary), and, therefore, each select line of the muxes 210 are set to “1F” (hex). As a result, the byte corresponding to the thirty-second mux data line, i.e., the last mux data line, is selected: dout(0-7)=VB(8-15), dout(8-15)=VB(16-23), . . . , dout(120-127)=VA(0-7). This equates to a shift right by 15 bytes, filling vacated bytes of the VA operand with zeroes from the VB operand.
[0032] [0032]FIG. 3 is a flow chart depicting steps that may be performed by the circuit 100 in accordance with one embodiment of the present invention that shifts an operand to the left or right a specified number of bytes. Processing begins in step 310 , wherein a shift instruction, such as vslo and/or vsro, is received and decoded. The shift instruction is decoded to determine, among other things, the type of instruction and hence the shift direction for vslo and vsro instructions. Upon receiving the instruction, in steps 320 and 322 , the VA operand and the VB operand is retrieved, respectively, from the specified source, such as a register file, bypass, load port, and/or the like, as is described above.
[0033] In step 324 , the VC operand is constructed. Preferably, as discussed above with reference to FIG. 1, the VC operand 130 comprises 16 bytes, each byte containing the shift direction in bit 3 and the shift amount in bits 4 - 7 . Also after step 322 , in step 326 , the VB operand 134 is filled with zeroes for the vslo and vsro instructions.
[0034] After steps 320 , 324 and 326 , processing proceeds to step 328 , wherein the VA operand 120 is shifted in the amount and direction specified by the VC operand 130 , filling the vacated bytes with the value of the VB operand 134 .
[0035] It is understood that the present invention can take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or the scope of the invention. For example, different data widths, such as 8, 16, 32, 64, 256, 512, and the like may be used, differing bit positions may be used for the VC mux selects, differing shift amounts, and/or different sources for the VC mux selects may be used.
[0036] Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention. | A method and an apparatus for performing a shift operation on an operand. The method and apparatus configures input lines to comprise a first part that includes the bits in order representing various shift amounts in a first direction and a second part that includes bits ordered representing various shift amounts in a second direction. The shift is then performed by selecting the appropriate bits from the input line to create the result. | 6 |
BACKGROUND OF INVENTION
This invention relates to power take-off mechanisms of the type including a power input shaft driveable from an engine by a friction clutch at one end of said shaft, and a two-speed power take-off shift driveable by gearing which includes disengageable toothed driving means and is disposed at the other end of the input shaft.
The disengageable toothed driving means of such mechanisms must only be operated when the friction clutch is disengaged. However, said means can be difficult and noisy to engage because the power input shaft tends to rotate due to inertia and drag when the friction clutch is disengaged. The object of the present invention is to overcome this problem.
SUMMARY OF INVENTION
According to the invention, a power take-off mechanism comprises a power input shaft driveable from an engine by a friction clutch at one end of said shaft, a two-speed power take-off shaft driveable by gearing which includes disengageable toothed driving means and is disposed at the other end of the input shaft, a control lever for operating the disengageable toothed driving means by way of a selector fork, and a brake for the input shaft applied by initial movement of the control lever in a direction to engage the disengageable toothed driving means and held applied whilst an operating load is being exerted on said lever in said direction.
BRIEF DESCRIPTION OF DRAWINGS
Two embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings of which:-
FIG. 1 is a sectional side elevation of a two-speed power take-off mechanism, for an agricultural tractor, of the type having its power take-off shaft reversible end-for-end;
FIG. 2 is a part-sectional elevation in the direction of the arrow 2 in FIG. 1;
FIG. 3 is a plan view of part of FIG. 2;
FIG. 4 is a sectional rear elevation of a two-speed power take-off mechanism, for an agricultural tractor, of the type incorporating change-speed gearing; and
FIG. 5 is a section on the line 5--5 in FIG. 4.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to FIGS. 1 to 3, one embodiment of two-speed power take-off mechanism for an agricultural tractor comprises a casing 10 housing a power input shaft 12 driveable from the tractor's engine by a friction clutch (not shown) at one end of said shaft, and a countershaft 11 co-axial with the input shaft 12 and capable of being connected thereto by a single dog clutch indicated generally at 13 which constitutes disengageable toothed driving means of the mechanism. Two gears 24 and 25 of different pitch circle diameters are fixed on (which expression if herein intended to mean integral with or rigidly secured on) the countershaft 11; a hollow drive shaft 28 parallel to the countershaft 11 has fixed on it a gear 26 meshing with the gear 24 and, at its rear end, a flange 33; and a drive sleeve 31 surrounding the drive shaft 28 has fixed on it a gear 29 meshing with the gear 25 and, at its rear end, a flange 32 the rear face of which lies in the same plane as that of the flange 33. The hollow drive shaft 28 and the drive sleeve 31 are therefore rotateable simultaneously at different speeds. A power take-off shaft 34 has differently splined end zones 35 and 36 each adapted to fit inoperatively within the hollow drive shaft 28, and a flange 37 between said zones adapted to be secured by set screws 42 to either one of the flanges 32 and 33 with axial clearance between the other of said flanges and the flange 37. Thus by turning the power take-off shaft 34 end-for-end in known manner it can be caused to rotate at, say, 540 revolutions per minute with a six-splined end zone projecting operably or 1000 revolutions per minute with a twenty-one splined end zone projecting operably. The dog clutch 13 comprises an externally toothed clutch sleeve 14 slideably on splines 15 at the rear end of the input shaft 12 by a selector fork 16 engaging in an annular groove 17 in the sleeve 14. The selector fork 16 is slideable on a dead shaft 18 by a hand control lever 21 between two positions in which the dog clutch 13 is respectively engaged and disengaged, and is held in each of said positions by conventional detent means consisting of a spring-loaded ball 22 in the selector fork 16 engageable in either of two annular grooves 23 in the dead shaft 18.
The input shaft 12 is provided with a band brake indicted generally at 49 which is operated by the control lever 21 in interdependence on the operation thereby of the dog clutch 13 as hereinafter described. To this end, a sleeve 51 is journalled in a bore formed through a boss 48 on a side wall of the casing 10, the axis of said bore lying in a plane perpendicular to the axes of the input shaft 12 and the power take-off shaft 34, and a spindle 50 is journalled in the sleeve 51. A brake band 52 is adjustably anchored at one end to a bracket 53 fixed within the casing 10, and is engageable with the input shaft 12 through an angle of 180°. The brake band 52 is offset from the axis of the spindle 50 as shown in FIG. 3, and its free end is operatively connected to a crank-pin 54 on a radial arm 59 formed at one end of the spindle 50. A radial arm 55 rigidly secured on the other, outer end of the spindle 50 is pivotally connected to the control lever 21 near one end thereof. The sleeve 51 has a crank-pin 56 at its outer end engaging in a fork 57 at said one end of the control lever 21, a radial arm 19 for moving the selector fork 16 along the dead shaft 18 is welded between the ends of the sleeve 51, and a stop 58 hereinafter referred to is welded to the inner end of the sleeve 51.
In operation, movement of the control lever 21 in a direction to engage the dog clutch 13 is initially resisted by the detent means 22 in the selector fork 16. The sleeve 51 therefore remains temporarily stationary and the control lever 21 fulcrums about the crank-pin 56 on the sleeve 51 and turns the spindle 50 to apply the band brake 49 thus ensuring that the input shaft 12 is at rest. When the force applied to the brake band 52 exceeds that required to overcome the detent means 22, the spindle 50 ceases to turn and continued movement of the control lever 21 in said direction causes said lever to fulcrum about its pivotal connection to the radial arm 55 on the spindle 50 and turn the sleeve 51 to move the selector fork 16 and engage the dog clutch 13 without difficulty or noise. When the selector fork 16 is held in engaged position by its detent means 22 and the operating load is removed from the control lever 21, there are sufficient clearances in the system to permit the release of the band brake 49. Engagement of the friction clutch then operates the power take-off shaft 34 at that one of the two available speeds determined by its orientation relative to the rest of the mechanism. When the friction clutch has been disengaged and the control lever 21 is moved in a direction to disengage the dog clutch 13, the resistance offered by the detent means 22 in the selector fork 16 causes the sleeve 51 to remain temporarily stationary and the control lever 21 initially fulcrums about the crank-pin 56 on the sleeve 51 and turns the spindle 50 in a direction to slacken the brake band 52 until the radial arm 59 on the spindle 50 contacts the stop 58 at the inner end of the sleeve 51. Continued movement of the control lever 21 in said direction then causes said lever, the spindle 50 and the sleeve 51 to turn in unison so as to move the selector fork 16 and disengage the dog clutch 13.
Referring now to FIGS. 4 and 5, another embodiment of two-speed power take-off mechanism for an agricultural tractor comprises a power input shaft 60 driveable from the tractor's engine by a friction clutch (not shown) at one end of said shaft, and a power take-off shaft 61 disposed in parallel overlapping relationship to the other end of the input shaft 60. Two gears 62 and 63 of different pitch circle diameters are fixed on the input shaft 60, and are capable of meshing respectively with two gears 64 and 65 formed integrally on a common hub 66 which is slideable on splines 67 on the power take-off shaft 61 and constitutes disengageable toothed driving means of the mechnism. A selector fork 68 engaging in an annular groove 69 in the hub 66 is moveable along a dead shaft 70 between three positions in the middle, neutral one of which there is no drive to the power take-off shaft 61 as shown in FIG. 5, in one end one of which said shaft is driven by way of the gears 62 and 64, and in the other end one of which said shaft is driven by way of the gears 63 and 65. The selector fork 68 is held in every one of its three positions by conventional detent means consisting of a spring-loaded ball 71 in the selector fork 68 engageable in any of three annular grooves 72 in the dead shaft 70. The mechanism is housed within a casing 73, through a boss 74 on a side wall of which there is formed a bore the axis of which lies in a plane perpendicular to the axes of the input shaft 60 and the power take-off shaft 61. Journalled in the bore is a sleeve 75 surrounding a spindle 76. A band brake indicated generally at 86 comprises a brake band 77 which is adjustably anchored at one end to a bracket 78 fixed within the casing 73, and in engageable with the input shaft 60 through an angle of 180°. The brake band 77 is in line with the axis of the spindle 76 as shown in FIG. 5, and its free end has a slot 85 enabling it to be operatively connected to a crank-pin 79 at one end of the spindle 76. A radial arm 80 rigidly secured on the other, outer end of the spindle 76 is pivotally connected to a hand control lever 81 near one end thereof. The sleeve 75 has a crank-pin 82 at its outer end engaging in a fork 83 at said one end of the control lever 81, and a radial arm 84 welded between its ends for moving the selector fork 68 along the dead shaft 70.
In operation, movement of the control lever 81 in either direction away from neutral in order to engage together either the gears 62 and 64 or the gears 63 and 65 is initially resisted by the detent means 71 in the selector fork 68. The sleeve 75 therefore remains temporarily stationary and the control lever 81 fulcrums about a crank-pin 82 on the sleeve 75 and turns the spindle 76 so that its crank-pin 79 moves arcuately to one side of its dead centre position shown in FIG. 5 to apply the band brake 86 thus ensuring that the input shaft 60 is at rest. When the force applied to the brake band 77 exceeds that required to overcome the detent means 71, the spindle 76 ceases to turn and continued movement of the control lever 81 in said direction causes said lever to fulcrum about its pivotal connection to the radial arm 80 on the spindle 76 and turn the sleeve 75 to move the selector fork 68 and engage the chosen pair of gears 62, 64 or 63, 65 without difficulty or noise. When the selector fork 68 is held in the chosen engaged position by its detent means 71 and the operating load is removed from the control lever 81, there are sufficient clearances in the system to permit the release of the bank brake 86. Engagement of the friction clutch then operates the power take-off shaft 61 at that one of the two available speeds determined by whichever meshing pair of gears 62, 64 or 63, 65 is transmitting drive thereto from the input shaft 60. When the friction clutch has been disengaged and the control lever 81 is moved back towards neutral, the resistance offered by the detent means 71 causes the sleeve 75 to remain temporarily stationary and the control lever 81 initially fulcrums about the crank-pin 82 on the sleeve 75 and turns the spindle 76 so that its crank-pin 79 passes arcuately through and to the other side of its dead centre position to reapply the band brake 86 for the purpose of providing a force exceeding that required to overcome the detent means 71. The spindle 76 then ceases to turn and continued movement of the control lever 81 towards neutral causes said lever to fulcrum about its pivotal connection to the radial arm 80 on the spindle 76 and turn the sleeve 75 to move the selector fork 68 and disengage whichever pair of gears 62, 64 or 63, 65 has been in mesh. When the selector fork 68 is held in the disengaged position by its detent means 71 and the operating load is removed from the control lever 81, the clearances in the system again permit the release of the band brake 86.
In a modification of the embodiment shown in FIGS. 4 and 5, the gears 64 and 65 are individually rotateably but non-slideably mounted on the power take-off shaft 61 in constant mesh with the gears 62 and 63 respectively, and are adapted to be alternatively driveably connected to said shaft by a double dog clutch disposed between them which constitutes disengageable toothed driving means of the mechanism and is slideable between a middle, neutral position and two engaged positions by the selector fork 68.
Other kinds of brakes can equally well be employed. | In a tractor power take-off mechanism comprising an input shaft driveable from an engine by a friction clutch and a two-speed power take-off shaft driveable from the input shaft by gearing including a disengageable toothed driving member operable by a hand lever by way of a selector fork, the disengageable toothed driving member can be difficult and noisy to engage because the input shaft tends to rotate due to inertia and drag when the friction clutch is disengaged. The input shaft is therefore provided with a band brake applied by initial movement of the hand lever in a direction to engage the disengageable toothed driving member and held applied while an operating load is being exerted on the lever in that direction. A conventional detent holding the selector fork in disengaged position provides the resistance required to cause the brake to be applied before the lever can move the fork into engaged position. | 5 |
BACKGROUND
Amplifiers are used in many environments and are one of the most widely used electronic devices. Typical amplifiers receive a differential voltage and have a single output. Fully differential amplifiers may receive a differential voltage and have a differential output. Typically the output of the amplifier is controlled either by negative feedback, which largely determines the magnitude the voltage gain, or by positive feedback, which facilitates regenerative gain and oscillation (i.e., it attempts to keep the input constant).
FIG. 1 illustrates a front end of a fully differential amplifier 100 . The amplifier may include a first transistor 101 receiving a first input voltage Vip at a positive input terminal and a second transistor 102 receiving a second input voltage Vin at a negative input terminal of the amplifier 100 . The output Iout of the amplifier 100 is the difference in current between the collectors of transistors 101 and 102 (i.e., Ip−In). The output Iout is based upon the input voltages Vip and Vin and the tail current Itail present at the emitters of transistors 101 and 102 . The tail current is controlled by current mirror 103 . The current mirror may include a first transistor 104 , controlled by a fixed current source 106 , and a second transistor 105 , which provides the tail current Itail to the differential transistors 101 and 102 . The current mirror attempts to match the current passing through transistor 104 into transistor 105 . Accordingly Itail will be approximately equal to Ibias.
When there is a large differential input voltage (i.e., when the difference between the input to the positive terminal and the negative terminal of the amplifier is large), the output of the amplifier tends to become distorted because the transconductance Gm of the input transistors in the amplifier is non-linear. FIG. 1 b illustrates the output current versus the differential input voltages for the amplifier illustrated in FIG. 1 a . Ideally the output current would be linear over a large range of differential input voltages, as indicated in FIG. 1 b . However, because of the non-linear output current behavior of the transistors in the amplifier, the actual current output from the amplifier becomes distorted. Transconductance is the derivative of ratio of the current at the output port and the voltage at the input ports (Gm=(ΔIout/ΔVinput) of the amplifier. For the amplifier illustrated in FIG. 1 a , the transconductance can be calculated using equation 1.1:
Gm = ( α F × I tail 2 × V T ) ( 1 - tanh 2 ( V ip - V in 2 × V T ) ) ( 1.1 )
where α F is ratio of collector current to emitter current of transistors 101 and 102 and V T is the thermal voltage of transistors 101 and 102 . Because of the distortion caused by the transconductance of the amplifier at large differential input voltages the output of the amplifier becomes distorted. As seen in FIG. 1 c , the transconductance Gm of the amplifier is shaped like a bell curve. Accordingly, as the differential input voltage deviates from the operating point (i.e. zero), the output of the amplifier becomes distorted.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a is illustrates a conventional differential amplifier front end;
FIG. 1 b illustrates a comparison between the output current and the input differential voltages for the amplifier illustrated in FIG. 1 ;
FIG. 1 c is illustrates a comparison between the transconductance and the input differential voltages for the amplifier illustrated in FIG. 1 ;
FIG. 2 a illustrates an exemplary amplifier according to one embodiment of the present invention;
FIG. 2 b illustrates a comparison between the output current and the input differential voltages for the amplifier illustrated in FIG. 2 a;
FIG. 2 c illustrates a comparison between the transconductance and the input differential voltages for the amplifier illustrated in FIG. 2 a;
FIG. 3 illustrates another exemplary amplifier according to one embodiment of the present invention;
FIG. 4 a illustrates an exemplary absolute value circuit in accordance with the present invention;
FIG. 4 b illustrates a comparison of the current flowing through the absolute value circuit illustrated in FIG. 4 a for various input voltages Vipp−Vinn;
FIG. 5 a illustrates a comparison of the output voltage of the amplifier illustrated in FIG. 3 over a range of input voltages Vin;
FIG. 5 b illustrates a comparison of the transconductance the amplifier illustrated in FIG. 3 over a range of input voltages Vin;
FIG. 6 illustrates yet another exemplary amplifier according to one embodiment of the present invention;
FIG. 7 a illustrates a further exemplary amplifier according to one embodiment of the present invention.
FIG. 7 b illustrates a comparison of the current output from that absolute value circuit versus the input voltage to the amplifier illustrated in FIG. 7 a over a range of gain values K;
FIG. 7 c illustrates a comparison of the output current versus the input current Vin (Vipp−Vinn) for various gain values K at a design ratios of X:1;
FIG. 7 d illustrates a comparison of the normalized transconductance verses the input voltages Vin (Vip−Vin) for various gain values K at a design ratio of X:1;
FIG. 8 illustrates another exemplary amplifier according to one embodiment of the present invention;
FIG. 9 a illustrates yet another exemplary current modulator according to one embodiment of the present invention;
FIG. 9 b a comparison of the output current versus the input current (Vip−Vin) for the current modulator illustrated in FIG. 9 a.
DETAILED DESCRIPTION
Embodiments of the present invention provide an input stage for an operational amplifier including a current modulator that supplies a source current in common to a pair of transistors driven by differential input signals. The source current is modulated according to the differential input signals as well. When the differential input signals are equal, the source current is at its minimum. The source current increases as the input signals deviate. Coupled with the varying conductance of the transistors, the input stage generates output currents with improved linear behavior as compared to designs with non-modulated source currents.
An exemplary embodiment of an amplifier 200 in accordance with the present invention can be seen in FIG. 2 a . The amplifier 200 may include a differential amplifier 201 , current modulator 207 and current mirror 204 . The differential amplifier 201 may include a first transistor 202 receiving a first input voltage Vip and a second transistor 203 , matched to the first transistor 202 (i.e., having the same properties), receiving a second input voltage Vin.
The amplifier 200 may further include a current mirror 204 , which may include matching transistors 205 and 206 and resistors R 1 and R 2 . The current mirror attempts to match the current Itail to the current Iabs_out. The current Iabs_out is controlled by the current modulator 207 .
The current modulator 207 may generate an output current I ABS — OUT whose magnitude varies based on the differential input voltages supplied to the amplifier. The output current I ABS — OUT may follow a profile as shown in FIG. 2 b . As shown, the output current may have its minimum value when the input voltages are equal to each other (Vip=Vin). However, as the input voltages become unbalanced, the output current increases. The current modulator 207 may become saturated at some point, at which point the output current reaches a maximum value. The output current from the current modulator 207 may be mirrored as the source current to the amplifier 201 via current mirror 204 .
The current modulator 207 may receive input voltages Vipp and Vinn. Input voltages Vipp and Vinn may be based upon input voltages Vip and Vin, respectively. Vipp and Vinn may, for example, be modulated versions of Vip and Vin. By adjusting the voltage of Vipp and Vinn the profile of the output current I ABS — OUT may be further modified, as described in further detail below.
The differentially driven transistors of amplifier 201 provide further modulation to the source current. Considered in combination, the aggregate output current from the amplifier 201 (the difference of IP and IN) provides improved linearity over prior designs, as shown in FIG. 2 c.
FIG. 3 illustrates an amplifier 300 in which the current modulator is provided as an absolute value circuit. The absolute value circuit may include transistors 305 and 307 having a same relative size and transistors 306 and 308 having a same relative size. The collectors of transistors 305 and 307 may be connected and the collectors of transistors 306 and 308 are connected. Further, the emitters of transistors 305 and 306 are connected to a current source 309 and the emitters of 307 and 308 may be connected to a current source 310 . The base of transistors 305 and 308 may receive a modulated input voltage Vipp. The base of transistors 306 and 307 may receive a modulated input voltage Vinn.
The output Iout of the amplifier 300 is equal to Ip−In, where Ip is the current output from transistor 301 and In is the current output from transistor 302 . Iout may also be represented by equation 1.2:
I OUT = ( I P - I N ) = α F × I TAIL × tanh ( V IP - V IN 2 × V T ) ( 1.2 )
where α F is relationship of collector current (output current) to emitter current (input current) of transistors 301 and 302 and V T is the thermal voltage of transistors 301 and 302 . Accordingly, by using an absolute value circuit 207 to modulate the tail current Itail, the output Iout of amplifier 300 can be controlled.
FIG. 4 a illustrates the flow of current for an exemplary absolute value circuit 400 . The absolute value circuit may include transistors 401 and 402 , connected at their respective emitters and transistors 403 and 404 connected at their respective emitters. Transistors 401 and 403 may be matched transistors of a predetermined size. Further, transistors 402 and 404 may be matched and may be designed to be larger than transistors 401 and 403 by a design factor X. As seen in FIG. 4 a , current Iabs_out is formed by currents Iabs_p and Iabs_n.
As seen in FIG. 4 b , when Vipp−Vinn is equal to or greater than 0.25V, transistor 401 supplies most of Iabs_out and transistor 403 supplies virtually none of Iabs_out. Conversely, when Vipp−Vinn is equal to −0.25V, transistor 403 supplies most of Iabs_out and transistor 401 supplies virtually none of Iabs_out. However, because both currents are added together by the absolute value circuit 400 , Iabs_out, which is designated by the solid line in FIG. 4 b , has the same current at positive or negative excursions from the operating point.
In order to improve the linearity of the transconductance Gm of the amplifier, it is preferable to have a relative minimum output current Iabs_out of the absolute value circuit at the operating point (when Vipp is approximately equal to Vinn) and a relative maximum output current at large input differential voltages. In one embodiment, this effect (i.e., shaping the transconductance of the amplifier) is achieved by changing the relative sizing of transistors 401 - 404 . FIG. 4 b , for example, illustrates the flow of current through the absolute value circuit 400 when transistors 402 and 404 are 4 times the size of transistors 401 and 403 . Iabs_p and Iabs_n can be calculated using equations 1.3 and 1.4:
I abs_p = α F × I abs_tail { 1 + exp [ ( - V ipp - V inn V T ) + ln X ] } - 1
I abs_p = α F × I abs_tail { 1 + exp [ - ( - V ipp - V inn V T ) + ln X ] } - 1 ( 1.3 )
where α F is relationship of collector current (output current) to emitter current (input current) of transistors 401 (eq. 1.3) and 403 (eq. 1.4), V T is the thermal voltage of transistors 401 and 403 and X is the design factor (ratio of the size of transistor 401 to transistor 402 (eq. 1.3) and 403 to 404 (eq. 1.4)). Because transistor 401 is in parallel with transistors 403 , the output of the absolute value circuit Iabs_out is the combination of Iabs_p and Iabs_n and may be calculated using equations 1.5:
I abs_out = α F I abs_tail [ { 1 + exp ( ( - V ipp - V inn V T ) + ln X ) } - 1 + { 1 + exp ( - ( - V ipp - V inn V T ) + ln X ) } - 1 ] ( 1.5 )
As seen in FIG. 4 b , Iabs_out, represented by the solid line is the sum of Iabs_p (represented by the dotted line) and Iabs_n (represented by the dot-dash line) and has a relative maximum current at large differential inputs and a relative minimum current when Vipp is equal to Vinn. In one embodiment, the relative ratio X:1 of the transistors was selected to be 4:1.
FIG. 5 a illustrates the output current Iout versus the input current (Vip−Vin) for various design ratios X:1. As seen in FIG. 5 a , as X increases from 1 to 4, the output current Iout becomes more linear. As X increases from 4 to 8, the absolute value circuit begins to overcorrect the transconductance.
FIG. 5 b illustrates the normalized transconductance verses the input voltages Vin (Vip−Vin) for various design ratios X. As seen in FIG. 5 a , as the design ratio increases from 1 to 4, the transconductance Gm remains around 1 for a larger range of input voltages. Ideally, the larger the voltage range for which the transconductance remains flat (i.e., at 1 in this example), the more linear the output current Iout will be over that range of input voltages.
FIG. 6 illustrates another embodiment of an amplifier 600 . The amplifier 600 may include including a first transistor 601 receiving a first input voltage Vip and a second transistor 602 , matched to the first transistor 601 (i.e., having the same properties), receiving a second input voltage Vin. The amplifier 600 may further include a current mirror 603 , which may include matching transistors 604 and 605 and resistors R 1 and R 2 . The current mirror attempts to match the current Itail to the current Iabs_out. The current Iabs_out is controlled by the absolute value circuit 606 .
The amplifier 600 may further include a differential sensing circuit 607 . The differential sensing circuit may receive as its input, the input voltages Vip and Vin input into the amplifier. Based upon the input voltages, the differential sensing circuit may tune the transconductance of the amplifier to reduce distortion. This circuit may be used, for example, to modulate the input voltages Vin and Vip to provide the modulated voltages Vipp and Vinn to the current modulators discussed above. The differential voltage input to the absolute value circuit (Vipp and Vinn) is shifted, based upon a gain K, from the differential voltage input into the amplifier 600 (Vip and Vin). The modulated differential input voltage (Vipp−Vinn)=K×(Vip−Vin). The output current Iabs_out can be calculated using equations 1.6:
I
abs_out
=
α
F
I
abs_tail
[
{
1
+
exp
(
k
(
-
V
ipp
-
V
inn
V
T
)
+
ln
X
)
}
-
1
+
{
1
+
exp
(
-
k
(
-
V
ipp
-
V
inn
V
T
)
+
ln
X
)
}
-
1
]
(
1.6
)
FIG. 7 a illustrates an amplifier 700 using an exemplary differential sensing circuit. The output of the absolute value circuit 705 is modified based upon a gain value K which is generated by the differential sensing circuit. The differential sense circuit may include transistors 706 and 707 whose collectors are connected by resister R 5 . The collector of transistor 706 may be connected in series with resister R 6 , while the collector of transistor 707 is connected in series with resister R 7 . The base of transistor 706 may be connected to the positive input terminal receiving voltage Vip. Conversely, the base of transistor 707 may be connected to the negative input terminal receiving voltage Vin. Resister R 6 is connected to the base of transistor 709 , while resister R 7 is connected to the base of transistor 708 .
At Vip−Vin=0, no current flows through R 5 . Transistors 710 and 711 , which receive a bias voltage from voltage source 712 , are current sources pushing equal amount of current through 706 and 707 . When Vip−Vin is not equal to 0 more current is steered to 706 or 707 and this current passes through R 5 . The current flowing through resister R 5 enters the collectors of transistors 706 and 707 . The current output from transistors 706 and 707 flows through resisters R 6 and R 7 , respectively, which then generate a voltage at the base of transistors 708 and 709 . Transistor 708 passes a level shifted input Vinn into the absolute value circuit 705 . Likewise, transistor 709 passes a level shifted input Vipp into the absolute value circuit 705 . Vipp and Vinn are modulated based upon the gain value K. The gain value K=2×(R 7 /R 5 ). The gain value K is preferably set between 0.4 and 1, however the gain value may be set beyond those reference points in certain circumstances.
FIG. 7 b illustrates a comparison between the output current of the absolute value circuit Iabs_out versus the differential input voltage (Vip—Vin) at various gain values K. Note, FIG. 7 b is illustrated using a transistor ratio of 4 to 1 (design factor X=4). Resistors R 7 & R 5 may be fixed values determined when the amplifier is manufactured, or they may be variable, allowing the shape of the output current Iabs_out to be changed based upon operating conditions.
FIG. 7 c illustrates the output current Iout versus the input current Vin (Vipp−Vinn) for various gain values K at a design ratios of X:1. As seen in FIG. 7 c , as K increases from 0.4 to 1, the shape of the output current Iout changes.
FIG. 7 d illustrates the normalized transconductance verses the input voltages Vin (Vip−Vin) for various gain values K at a design ratio of X:1. As seen in FIG. 7 d , as the design ratio increases from 0.4 to 1, the shape of the transconductance Gm changes. In the exemplary illustration in FIGS. 7 c - d the gain value K is preferably set to 0.6, however, the preferable gain value K may change depending upon the design ratio X selected.
The above described absolute value circuits are merely an exemplary current modulator circuit which can linearize the transconductance of an amplifier. However, one of ordinary skill in the art would recognize that other circuits could accomplish a similar function. For example, a class AB differential input stage could be used
FIG. 8 illustrates an amplifier 800 using a class AB differential input stage 807 . The amplifier 800 may include a differential amplifier 801 , class AB differential input stage 807 and current mirror 804 . The differential amplifier 801 may include a first transistor 802 receiving a first input voltage Vip and a second transistor 203 , matched to the first transistor 802 (i.e., having the same properties), receiving a second input voltage Vin.
The amplifier 800 may further include a current mirror 804 , which may include matching transistors 805 and 806 and resistors R 1 and R 2 . The current mirror attempts to match the current Itail to the current Iabs_out. The current Iabs_out is controlled by the class AB differential input stage 807 .
The class AB differential input stage 807 may generate an output current whose magnitude varies based on the differential input voltages, for example, modulated input voltages Vipp and Vinn, supplied to the amplifier.
FIG. 9 a illustrates an exemplary class AB differential input stage. The class AB differential input stage may include transistors 901 and 902 and may have their collectors connected and their emitters connected through a resistor R. The base of transistors 901 and 902 may be connected to a current source Ibias and to the emitters of transistors 903 and 904 , respectively. The collectors of transistors 903 and 904 may be connected to ground. The base of transistors 903 and 904 may receive the modulated input voltages Vipp and Vinn, respectively. Transistors 907 and 908 may also receive the input modulated voltages Vipp and Vinn at their respective bases. The emitters of transistors 907 and 908 may be connected to the current source Ibias and may also be connected to the base of transistors 905 and 906 , respectively. The emitters of transistors 905 and 906 may be connected to each other through the resistor R. The collectors of transistors 905 and 906 may be connected to ground.
FIG. 9 b illustrates a comparison between the current output labs from the class AB differential input stage and the input voltage Vin (i.e., Vin−Vip). As seen in FIG. 9 b , as the input voltage deviates from zero (i.e., the operating point), the current output from the current modulator increases. As seen in FIG. 9 b , the shape of the output current labs may be selectively changed by selecting the resistance of resistor R and the current of the current source Ibias.
Transistors 901 , 903 , 905 and 907 may form half of the class AB differential input stage, while transistors 902 , 904 , 906 and 908 may form the other half. Each half of the class AB differential input stage may attempt to force the input voltage (i.e., Vip or Vin) to the emitters of transistors 901 , 905 , 902 and 906 , respectively. Since the emitters of transistors 901 , 905 , 902 and 906 are connected through resistor R, the difference in voltage Vip−Vin will be forced across the resistor R. The difference between the input voltages, divided by the resistance of resistor R will be equal to the output current labs, which is used to modulate the tail current of the amplifier.
Several embodiments of the invention are specifically illustrated and/or described herein. However, it will be appreciated that modifications and variations of the invention are covered by the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention. | The invention is directed to an amplifier including an absolute value circuit. The absolute value circuit may be driven by differential potentials and may include a first pair of transistors modulating a tail current of the amplifier when a differential input voltage goes high, and a second pair of transistors modulating the tail current of the amplifier when a differential input voltage goes low. | 7 |
BACKGROUND OF THE INVENTION
This invention relates to therapeutic agents and, in particular, to 1-phenylindole derivatives which are valuable as antidiarrhoeal agents.
Diarrhoea is one of the major causes of morbidity and mortality in the world, and in developing countries it accounts for more infant fatalities than any other single cause. Even in North America and Europe it is a leading cause of death or debilitation among both the young and the elderly. Severe diarrhoea is most commonly caused by an infection of the small intestine; however, the microorganism itself does not invade the intestinal mucosa but produces an enterotoxin which is believed to be responsible for stimulating active electrolyte secretion and consequent fluid loss.
Although the introduction of oral hydration therapy has greatly simplified the treatment of dehydrating diarrhoea, drugs that reduce the rate of fluid loss also have an important role in the management of the condition. One such drug which has recently been identified as a promising antisecretory drug for use in the treatment of dehydrating diarrhoea is chlorpromazine. However, chlorpromazine also has marked effects on the central nervous system at the dosages used, most notably sedation. The present invention provides compounds which are useful in the treatment of diarrhoea but which are believed to have significantly reduced sedative effects.
SUMMARY OF THE INVENTION
In accordance with the invention there is provided a substituted phenylindole of the formula: ##STR2## and the pharmaceutically-acceptable acid addition salts thereof;
wherein R is hydrogen, chloro, bromo, --CH(OH).Ph or --CH(OH).cyclohexyl; each Ph is phenyl or substituted phenyl; n is an integer of from 2 to 7; and each of R 1 and R 2 is hydrogen or (C 1 -C 4 ) alkyl, or R 1 and R 2 taken together with the nitrogen atom to which they are attached form a heterocyclic group of the formula: ##STR3##
where R 3 is hydrogen or (CH 1 -C 4 ) alkyl.
Each Ph is preferably either unsubstituted phenyl, or phenyl substituted with 1 to 3, more preferably 1 or 2, substituents selected from (C 1 -C 4 ) alkyl, (C 1 -C 4 ) alkoxy, F, Cl, Br, I and CF 3 .
The invention further provides a method of treating diarrhoea in a patient, which comprises administering to said patient an effective amount of a compound of the formula (I) or a pharmaceutically-acceptable acid addition salt thereof.
Preferred compounds of the invention are those of formula (I) wherein R is hydrogen, chloro or bromo, more particularly wherein R is hydrogen.
"n" in one aspect is preferably 2, 3, 4 or 5, more preferably 2 or 3.
In another aspect "n" is 6 or 7, more preferably 6.
Each of R 1 and R 2 is hydrogen or (C 1 -C 4 ) alkyl, more preferably hydrogen or methyl. Most preferably each of R 1 and R 2 is methyl.
"Ph" is preferably unsubstituted phenyl.
In the preferred individual compound, R is hydrogen R 1 and R 2 are methyl, n is 6 and Ph is unsubstituted phenyl.
DESCRIPTION OF THE INVENTION
The compounds of the formula (I) in which R is hydrogen may be prepared by reacting a salt of the formula: ##STR4## where Ph is as previously defined and M + is an alkali metal or alkaline earth metal cation, with a compound of the formula:
Q.(CH.sub.2).sub.n.NR.sup.1 R.sup.2 (III)
or an acid addition salt thereof, where n, R 1 and R 2 are as defined above and Q is a leaving group, e.g. chloro, bromo, tosyloxy, etc.
Q is preferably chloro. M is preferably an alkali metal, most preferably sodium or potassium.
The compounds of the formula (II) are preferably generated in situ by the reaction of a compound of the formula: ##STR5## or an acid addition salt thereof, with an alkali metal hydroxide or alkaline earth metal hydroxide such as sodium hydroxide or potassium hydroxide.
Some of the compounds of the formula (III) are unstable in their free base forms, and in these cases they should be used in acid addition salt form (eg as hydrochlorides). Such compounds are in fact often commercially available as hydrochlorides.
Thus a typical reaction involves the reaction of compound (IV), optionally in acid addition salt form such as a hydroiodide, with aqueous sodium hydroxide, preferably with heating at up to reflux. Excess sodium hydroxide should be used if compound (IV) is used in acid addition salt form. After stirring for a short period, compound (III) is added to the suspension, if necessary in acid addition salt form. The resulting reaction is generally exothermic. The product can then be isolated and purified conventionally. In some cases, the product can be isolated directly in acid addition salt form.
The starting materials (IV) can be obtained conventionally, e.g. as follows: ##STR6##
If desired, acid addition salts may be prepared from the free base forms by reaction of a solution of the free base in a suitable organic solvent, e.g. dry methanol, with a solution of the desired acid in a suitable organic solvent, e.g. dry methanol, and either evaporating the solvent or recovering the salt as a precipitate.
In an alternative to the above, the compounds (II) can be reacted as follows to prepare the end products of the formula (I): ##STR7## R 1 , R 2 , Q and n are as defined for formula (I); Q is preferably Br in this alternative.
Again it is preferred to generate the compound (II) in situ by reacting the compound (IV) with aqueous sodium hydroxide at up to the reflux temperature, e.g. 90° C. The compound (IIIA) is then added in a suitable organic solvent, e.g. ethanol, and the reaction mixture heated at up to the reflux temperature for a few hours. The crude intermediate (V) is then recovered from the reaction mixture and reacted with the compound R 1 R 2 NH in a suitable organic solvent, e.g. tetrahydrofuran, and generally at low temperature, typically 0° to 10° C. The product (I) can then be isolated and purified conventionally.
The compound (IV) can again be reacted in acid addition salt form and in this case, as before, excess sodium hydroxide should be used.
Compounds in which R is --CH(OH).Ph or --CH(OH).cyclohexyl can be prepared from the corresponding compounds (or their acid addition salts) in which R is H, firstly by reaction with a strong base such as n-butyllithium and then with, respectively, the appropriate benzaldehyde or cyclohexane carboxaldehyde. Typically the reaction with n-butyllithium is carried out at low temperature, e.g. -40° C., in an organic solvent, such as tetrahydrofuran. The reaction mixture is then maintained at low temperature, e.g. -25° C., for a few hours, and then cooled to about -70° C. before the dropwise addition of the aldehyde in e.g. tetrahydrofuran. The reaction mixture is then slowly allowed to warm to room temperature and evaporated. The desired product can be recovered from the residue and purified by conventional techniques.
Compounds in which R is Cl or Br can be prepared by a 2-stage reaction from the corresponding compounds in which R is H, as follows: ##STR8##
The reaction can be carried out conventionally (see Example 4).
Acids from which pharmaceutically acceptable addition salts of the compounds of the invention can be prepared are those which form non-toxic addition salts containing pharmaceutically acceptable anions, such as the hydrochloride, hydrobromide, hydroiodide, sulphate or bisulphate, phosphate or acid phosphate, acetate, maleate, fumarate, lactate, tartrate, citrate, gluconate, saccharate and p-toluene sulphonate salts.
The compounds of the invention are valuable for the treatment of diarrhoea in both humans and animals, especially for the treatment of severe forms of diarrhoea of bacterial origin, for example, associated with E. coli infections in humans and enteritis in pigs. The compounds are also of value in treating milder forms of the condition such as travellers' diarrhoea.
The activity of the compounds is assessed using a test procedure based on that described by Giannella in Infection and Immunity 1976, 14, 95-99, in which the ability of the compounds to inhibit the intestinal secretion induced by administration of an enterotoxin is measured in suckling mice. In practice a group of mice are given an oral dose of a heat stable toxin produced by E. coli as described by Staples et. al., J. Biol. Chem., 1980, 255, 4716. This induces intestinal fluid secretion and causes an increase in gut weight relative to that of the remaining carcass. A further group of mice are dosed with the toxin followed by the compound under investigation at various dose levels. After 21/2 hours at 23° C. the mice are killed and the weight of the gut measured as a proportion of the remaining carcass. The percentage inhibition at various dose levels is then calculated. The test can also be performed using a heat labile enterotoxin, produced for example by Vibrio cholerae as described by Kusama and Craig, Infection and Immunity, 1970, 1, 80.
For human use, the anti-diarrhoeal compounds of the formula (I) can be administered alone, but will generally be administered in admixture with a pharmaceutical carrier selected with regard to the intended route of administration and standard pharmaceutical practice. For example, they may be administered orally in the form of tablets containing such excipients as starch or lactose, or in capsules or ovules either alone or in admixture with excipients, or in the form of elixirs or suspensions containing flavouring or colouring agents. They may be injected parenterally, for example, intravenously, intramuscularly or subcutaneously. For parenteral administration, they are best used in the form of a sterile aqueous solution which may contain other substances, for example, enough salts or glucose to make the solution isotonic.
For oral administration to human patients, the daily dosage level of the anti-diarrhoeal compounds of the formula (I) will be from 1-40 mg./kg., preferably 5-10 mg./kg. (in divided doses). Thus tablets or capsules of the compounds can be expected to contain from 5 mg to 25 mg of active compound for administration singly or two or more at a time as appropriate. In any event the physician will determine the actual dosage which will be most suitable for an individual patient and it will vary with the age, weight and response of the particular patient. The above dosages are exemplary of the average case but there can, of course, be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention.
The preparation of the compounds of the formula (I) is illustrated by the following Examples. All temperatures are in °C.:
EXAMPLE 1
(A) 2-(1-phenylindol-3-yl)-2-thioisourea hydroiodide ##STR9##
N-Phenylindole (28.95 g; 0.15M) and thiourea (11.4 g; 0.15M) were dissolved in a mixture of methanol (140 ml) and ethanol (100 ml) by rapid stirring at 20°. To this solution was added in four portions a solution of potassium iodide (52.5 g; 0.3M) and iodine (38.1 g; 0.15M) in water (60 ml) over 10 minutes. The solution was then stirred at 20° for 17 hours. The resulting heavy yellow precipitate of the crude product was filtered off, washed successively with isopropanol (3×200 ml), water (3×200 ml), isopropanol (3×200 ml) and ether (2×200 ml), and then dried at 60° to give the title compound, weight 46.2 g (78.0% yield). An analytical sample was prepared by crystallisation from a 1:1 mixture of methanol and ethanol. This gave colourless rhombohedral crystals of the title compound, m.p. 264°-6°.
Analysis %: Calculated for C 15 H 13 N 3 S.HI: C,45.5; H,3.5; N,10.6; Found: C,45.1; H,3.4; N,10.1.
N.m.r. and i.r. were constistent with the stated structure.
(B) 3-(3-[N,N-Dimethylamino]propylthio)-1-phenylindole hydrochloride ##STR10##
A suspension of the hydroidide salt from part (A) (27.0 g; 0.07M) in 2N aqueous sodium hydroxide (300.0 ml) was stirred under nitrogen and heated to reflux. After 10 minutes the mixture was cooled to 90° and solid 3-[dimethylamino]-propyl chloride hydrochloride (21.6 g; 0.14M) was added in small portions. A vigorous exothermic reaction occcurred and the solid dissolved. The solution was allowed to cool and was stirred at 20° for a further 17 hours. The resulting two-phase mixture was extracted with methylene chloride (3×100 ml.), and the combined organic extracts were washed with water (2×50 ml), dried (magnesium sulphate) and evaporated to give a viscous pale green oil. This was dissolved in 3.5N methanolic hydrogen chloride (50 ml.), evaporated and the residue was crystallised from acetonitrile (1200 ml.) to give the title compound as colourless leaflets, weight 11.3 g, m.p. 203°-7° (46.0% yield).
Analysis %: Calculated for C 19 H 22 N 2 S.HCl: C,65.8;H,6.7;N,8.1; Found: C,65.6;H,6.8;N,8.0.
EXAMPLES 2 and 3
The following compounds were prepared similarly to Example 1(B), starting from the same hydroiodide salt and, respectively, Cl(CH 2 ) 3 NH 2 .HCl and Cl(CH 2 ) 2 N(CH 3 ) 2 .HCl:
______________________________________ ##STR11##EX- Analysis %AM- (Theoretical inPLE m.p. brackets)NO. n R.sup.1 R.sup.2 Form Isolated (°C.) C H N______________________________________2 3 H H Hydrochloride 139- 62.6 6.0 8.7 hemihydrate 40° (62.3 6.1 8.5)3 2 CH.sub.3 CH.sub.3 Hydrochloride 178- 64.5 6.3 8.3 183° (64.9 6.4 8.4)______________________________________
The product of Example 2 was crystallised from isopropanol (94% yield). The product of Example 3 was crystallised from isopropanol/dry ethyl acetate (36.2% yield).
EXAMPLE 4
(A) 3-(3-[N,N-dimethylamino]propylsulphinyl)-1-phenylindole, free base and maleate ##STR12##
A solution of m-chloroperbenzoic acid (3.1 g; 0.018M) in dry methylene chloride (50 ml) was added dropwise to a stirred solution of 3-(3-[N,N-dimethylamino]propylthio)-1-phenylindole hydrochloride (5.20 g; 0.015M) in a mixture of dry methylene chloride (125 ml) and dry methanol (3 ml) at 20°. After 17 hours, the solution was washed with 5% aqueous sodium carbonate (250 ml), dried (magnesium sulphate) and evaporated. The residual oil was purified by chromatography under slight excess pressure (0.2 kg.cm. 2 ) on a 200 g. Merck "Kieselgel 60" (Trade Mark) (230-400 mesh) silica-packed column (diameter 75 mm.) eluting with ethyl acetate/diethylamine firstly in a ratio of 98:2 v/v (1 liter), then 95:5 v/v (1 liter) and then 90:10 v/v until the product was eluted. The product-containing fractions were combined and evaporated to give the free base form of the title compound, weight 3.5 g (71.5% yield). A solution of maleic acid (96 mg; 0.00082M) in dry methanol (2 ml.) was added to a solution of said free base (270 mg; 0.00082M) in dry methanol (10 ml) and the solvent was evaporated. The residue was crystallised from dry ethyl acetate to give the title compound, maleate salt, weight 248 mg, m.p. 116°-9° (73.8% yield).
Analysis %: Calculated for C 19 H 22 N 2 OS.C 4 H 4 0 4 : C,62.4; H, 5.9; N,6.3; Found: C,62.2; H,5.8; N,6.5.
N.m.r, i.r. and mass spectral data were consistent with the stated structure.
(B) 2-Chloro-3-(3-[N,N-dimethylamino]propylthio)-1-phenylindole, free base and hydrochloride ##STR13##
4.4N Methanolic hydrogen chloride (8 ml) was added to a solution of the free base of 3-(3-[N,N-dimethylamino]propysulphinyl)-1-phenylindole (3.5 g; 0.0107M) in dry methanol (40 ml) and the solvent was evaporated. Further 4.4N methanolic hydrogen chloride (8 ml) was added to the residue and the solvent was again evaporated. The residue was dissolved in methylene chloride (400 ml), washed with 5% aqueous sodium carbonate (400 ml), dried (magnesium sulphate) and evaporated. The residual oil was purified by chromatography under slight excess pressure (0.2 kg cm 2 ) on a 60 g. Merck "Kieselgel 60" (Trade Mark) (230-400 mesh) silica-packed column (diameter 50 mm) eluting with ethyl acetate/isopropanol/0.88 S.G. NH 4 OH firstly in a ratio of 98:2:1.5 v/v/v (400 ml.), then 96:4:3 v/v/v (400 ml.) and finally 94:6:4.5 until the product was eluted. The product-containing fractions were combined and evaporated to give the free base form of the title compound, weight 2.14 g. (57.8% yield). 4.4N Methanolic hydrogen chloride (3 ml) was added to a solution of said free base (200 mg; 0.00058M) in dry methanol (10 ml) and the solvent was then evaporated. The residue was crystallised from dry ethyl acetate to give the title compound as a hydrochloride weight 171 mg, m.p. 171°-6° (77.3% yield).
Analysis %: Calculated for C 19 H 21 ClN 2 S.HCl: C,59.8; H,5.8; N,7.3; Found: C,60.0; H,5.9; N,7.6.
N.m.r., i.r. and mass spectral data were consistent with the stated structure.
EXAMPLE 5
1-Phenyl-3-[6-(N,N-dimethylamino)-n-hexylthio]indole citrate ##STR14##
1-Phenylindole-3-isothiuronium iodide (5 g; 12.65 mMole) was heated at 90° with stirring under nitrogen in 2N aqueous sodium hydroxide for 25 minutes. On cooling to room temperature, 1,6-dibromohexane (12.2 g; 0.05 mole) was added in absolute ethanol (50 ml) and the reactants were vigorously stirred under reflux for 5 hours. The aqueous layer was separated from the resultant two-phase mixture and extracted with ether (2×50 ml). The combined organic layer and organic extracts were washed with water (100 ml), dried (magnesium sulphate) and evaporated. The excess 1,6-dibromohexane was removed by distillation (115°/10 mmHg) and the residual tar was dissolved in anhydrous tetrahydrofuran (30 ml). To the stirred solution at 0° was added anhydrous dimethylamine (5 ml; 0.075 mole) and the reactants were stirred at 5°±5° for 1 hour and then at room temperature for 15 hours. The solution was filtered, the filtrate evaporated and the residue partitioned between methylene chloride (30 ml) and water (30 ml). The aqueous layer was separated and further extracted with methylene chloride (2×30 ml). The combined organic layer and organic extracts were washed with brine, dried (magnesium sulphate) and evaporated. The residual oil was purified by medium pressure chromatography (0.14 Kg cm -2 ) on a 30 g. Merck "Kieselgel 60" (230-400 mesh) (Trade Mark) silica-packed column (diameter 40 mm), eluting with chloroform/methanol/0.88 ammonia, firstly in the ratio of 98:2:0.2 v/v (200 ml) and then 90:10:1 (200 ml). Fractions containing the product as the major component (as evidenced by thin layer chromatographic analysis) were evaporated to give an oil (2 g). 1.05 g of this oil was dissolved in sodium-dried ether (5 ml) and a solution of citric acid hydrate (0.625 g; 3.25 mMole) in methanol (2 ml) was added. The ensuing solid was triturated with sodium-dried ether (10 ml), filtered and the solid product recrystallised from acetone/ether and vacuum-dried at 70° for 15 hours to give the title compound, weight 1.33 g, m.p. 86-88°, (35% yield).
Analysis %: Found: C,61.8; H,6.8; N,5.1; Calculated for C 22 H 28 N 2 S.C 6 H 8 O 7 : C,61.7; H,6.7; N,5.1.
N.M.R. and i.r. spectral data were consistent with the stated structure.
EXAMPLE 6
1-Phenyl-2-(1-phenyl-hydroxymethyl)-3-(3-N,N-dimethylaminopropylthio)indole oxalate ##STR15##
A solution of n-butyllithium in hexane (12.5 ml of a 1.6M solution; 20 mMole) was added dropwise to a stirred suspension of the hydrochloride of 1-phenyl-3-(3-N,N-dimethylaminopropylthio)indole (1.04 g; 3 mMole) in dry tetrahydrofuran (40 ml) at -40° in an atmosphere of nitrogen. The solution obtained was maintained at -25° for 3 hours, cooled to -70° and a solution of benzaldehyde, (4.3 g; 40 mMole) in dry tetrahydrofuran (10 ml) was added dropwise. The solution was allowed to warm up to +20° over a period of 17 hours and then evaporated. The residue was dissolved in a mixture of 0.5N hydrochloric acid (200 ml) and methylene chloride (200 ml) which was basified to pH 10 by addition of solid sodium carbonate. The resulting separated aqueous layer was extracted with methylene chloride (2×100 ml) and the combined organic layer and organic extracts were dried (magnesium sulphate) and evaporated. The residual oil was purified by medium pressure chromatography (0.2 Kgcm -2 ) on a 60 g Merck "Kieselgel 60" (230-400 mesh) silica-packed column (diameter 50 mm) eluting with ethyl acetate/propan-2-ol/concentrated aqueous ammonia firstly in the ratio 98:2:0.5 (500 ml), then 97:3:2 (500 ml) and then 96:4:2.5 (500 ml). The appropriate fractions were combined and evaporated and the residual oil (743 mg; 1.77 mMole) was dissolved in methanol (10 ml). A solution of anhydrous oxalic acid (160 mg; 1.77 mMole) in methanol (2 ml) was added, the solution evaporated and the residue crystallised from ethyl acetate/cyclohexane to give the title compound, weight 783 mg; m.p. 160°-4°, (51.6% yield).
Analysis: Found: C,66.1; H,6.0; N, 5.4; Calculated for C 26 H 28 N 2 OS.C 2 H 2 O 4 : C,66.4; H,6.0; N,5.5.
N.M.R., i.r. and mass spectral data were consistent with the stated structure.
EXAMPLE 7
1-Phenyl-2-(1-cyclohexyl-hydroxymethyl)-3-(3-N,N-dimethylaminopropylthio)indole oxalate ##STR16##
A solution of n-butyllithium in hexane (7.5 ml of a 1.6M solution; 12 mMole) was added dropwise to a stirred suspension of the hydrochloride of 1-phenyl-2-(3-N,N-dimethylaminopropylthio)indole (693 mg; 2 mMole) in dry tetrahydrofuran (20 ml) at -40° in an atmosphere of nitrogen. The solution obtained was maintained at -25° for 3 hours, cooled to -70° and a solution of cyclohexane carboxaldehyde (2.8 g; 25 mMole) in dry tetrahydrofuran (5 ml) was added dropwise. The solution was allowed to warm up to +20° over a period of 17 hours and then evaporated. The residue was dissolved in a mixture of 0.5N hydrochloric acid (50 ml) and methylene chloride (50 ml) which was basified to pH 10 by addition of solid sodium carbonate. The resulting separated aqueous layer was extracted with methylene chloride (2×50 ml) and the combined organic layer and extracts were dried (magnesium sulphate) and evaporated. The residual oil was purified by medium pressure chromatograpy (0.2 kg cm -2 ) on a 50 g Merck "Kieselgel 60" (230-400 mesh) silica-packed column (diameter 50 mm) eluting with ethyl acetate/propan-2-ol/concentrated aqueous ammonia firstly in the ratio 98:2:0.5 (500 ml), then 97:3:1 (500 ml) and then 96:4:1.5 (500 ml). The appropriate fractions were combined and evaporated and the residual oil (480 mg; 1.14 mMole) was dissolved in methanol (10 ml). A solution of anhydrous oxalic acid (102 mg; 1.14 mMole) in methanol (2 ml) was added, the solution evaporated and the residue crystallised from ethyl acetate to give the title compound, weight 458 m.p. 138°-143°, (44.7% yield).
Analysis %: Found: C,65.5; H,7.4; N,5.4; Calculated for C 26 H 34 N 2 OS.C 2 H 2 O 4 : C,65.6; H,7.1; N,5.5.
N.M.R., i.r. and mass spectral data were consistent with the stated structure. | Substituted phenylindoles, useful as anti-diarrhoeal agents and having the formula: ##STR1## and the pharmaceutically-acceptable acid addition salts thereof; wherein R is hydrogen, chloro, bromo, --CH(OH).Ph or --CH(OH).cyclohexyl; each Ph is phenyl or substituted phenyl; n is an integer of from 2 to 7; and each of R 1 and R 2 is hydrogen or (C 1 -C 4 ) alkyl, or R 1 and R 2 taken together with the nitrogen atom to which they are attached form a heterocyclic group; and a method for the treatment of diarrhoea by the administration of said agents. | 2 |
TECHNICAL FIELD
[0001] The present invention relates to the general technical field of horology, and more particularly the technical field of escapement systems. The invention in particular relates to free escapement systems for mechanical watches, and more generally any system for transferring energy from a disc moving in a single direction to a disc with an alternating movement.
[0002] Such an escapement system generally comprises an escape-wheel subject to a quasi-constant torque provided by a barrel and reduced by a gear train. The escapement system also comprises an escapement pallet serving to distribute the energy provided by the escape-wheel in a given direction, alternating in one direction then the other, to a plate. For a mechanical watch, such a plate is secured in rotation to a sprung balance.
BACKGROUND OF THE INVENTION
[0003] Escapement systems are known and are consequently not described in detail in this document. These systems include a set of component parts in particular including at least one escape-wheel intended on the one hand to be rotated under the action of at least one drive organ, and on the other hand to cooperate mechanically with at least one regulating organ, to periodically transmit energy to it in order to maintain its oscillations.
[0004] Typically, the escape-wheel includes a hub, a felloe provided with teeth and connecting arms rigidly connecting the hub to the felloe.
[0005] The most widespread escapement mechanism is the Swiss lever escapement, due in particular to its reliability.
[0006] Also known is a pallet escapement by the Melly brothers, the escapement pallet of which includes a stick connecting a body, bearing pallet-stones, to a fork. Such an escapement is for example described in application EP 1,967,919. The stick pivots around a fixed axis parallel to the axis of an escape-wheel. It is widely known that such an escapement does not work properly. In fact, this escapement does not have high operating safety, the transitions between rest, impulse and drop being poorly defined. It is also very bulky and its construction gives it a strong moment of inertia.
BRIEF DESCRIPTION OF THE INVENTION
[0007] The present invention aims to provide an improved escapement mechanism, making it possible to increase the efficiency of an escapement system.
[0008] Another aim of the present invention is to provide a simple, reliable and compact escapement mechanism.
[0009] To that end, and according to the present invention, an escapement mechanism is proposed for a timepiece comprising an escape-wheel, an escapement pallet including a body, a fork secured to said body, said body including pallet-stones intended to cooperate with the escape-wheel, said body having a shape making it possible to delimit an inner space for arranging the escape-wheel, said pallet-stones on the one hand comprising two rest pallet-stones and on the other hand two impulse pallet-stones, protruding in the inner space, said mechanism including a pin of a plate secured to a regulating organ, characterized in that the plate and the fork are arranged relative to one another so as, when the pin cooperates with the fork, to impart an alternating translational movement to the pallet in a direction making it possible to bring the pallet closer to and further away from the regulating organ.
[0010] According to one example embodiment of the invention, the translational movement occurs in a direction T perpendicular to the fork opening.
[0011] According to one example embodiment of the invention, the plate has an axis of rotation parallel to the axis of rotation of the escape-wheel, such that the pin having an alternating rotational movement cooperates with input and output horns of said fork.
[0012] According to one example embodiment of the invention, the impulse pallet-stones and the rest pallet-stones have different shapes.
[0013] According to one example embodiment of the invention, the impulse pallet-stones, like the rest pallet-stones, are symmetrical relative to a central axis and normal to the extension plane of the inner space delimited by the body.
[0014] According to one example embodiment of the invention, the rest pallet-stones have a shape allowing either so-called “shoulder” positioning of the teeth of the escape-wheel, or positioning by fixed bankings limiting the travel of the pallet.
[0015] According to one example embodiment of the invention, each rest pallet-stone has, starting from its free end, an impulse beak, an impulse plane, a rest beak, a rest plane and a return plane.
[0016] According to one example embodiment of the invention, each impulse pallet-stone has, starting from the free end, an impulse beak, an impulse plane, a first additional plane and a second additional plane so as to produce a substantially bent shape in a direction opposite the direction of rotation of the escape-wheel.
[0017] According to one example embodiment of the invention, each impulse pallet-stone has a countersink extending upstream from its impulse plane, to house the beak and impulse plane of a tooth of the escape-wheel therein without contact.
[0018] According to one example embodiment of the invention, the body is a substantially annular part including two substantially rectilinear central parts and one substantially circular portion at the ends of said central parts, thus defining a geometric shape of the inner space having a large axis combined with a direction of translation T passing through the center of the escape-wheel, each of the pallet-stones being arranged in a transition area between a central part and a substantially circular portion.
[0019] According to one example embodiment, the escapement mechanism according to the invention makes it possible to implement, via the alternating translational movement of the escapement pallet, repetitive escapement cycles each comprising a rest phase, an unlocking phase, an impulse phase on a rest pallet-stone, a complementary impulse phase on an impulse pallet-stone and a drop phase of the escape-wheel preceding a new rest phase, said phases corresponding to particular positions of the escapement pallet on its translational journey.
[0020] According to one example embodiment according to the invention, each tooth of the escape-wheel has, at its free end, a beak acting on the impulse plane of a rest pallet-stone during the impulse phase and an impulse plane acting on the impulse plane of an impulse pallet-stone during the complementary impulse phase.
[0021] According to one example embodiment of the invention, during a rest phase, the beak and the impulse plane of a tooth of the escape-wheel are engaged without contact in the countersink of the impulse pallet-stone preceding the rest palette-stone against which another tooth abuts.
[0022] According to one example embodiment of the invention, the body, the fork connected to said body by means of a stick, the rest palette-stones and the impulse pallet-stones are connected in a single piece.
[0023] According to another example embodiment of the invention, different materials are used to produce parts or elements, for example such as ruby to produce the pallet-stones and steel to produce the body.
[0024] According to another preferred example embodiment of the invention, the impulse planes of the impulse pallet-stones are oriented such that the bearing of the teeth is as close as possible to the direction of translation of the pallet.
[0025] The present invention also relates to a timepiece including at least one escapement mechanism according to the invention.
[0026] The escapement mechanism according to the invention makes it possible to improve the transmission of energy between the escape-wheel and the escapement pallet.
[0027] The escapement mechanism according to the invention makes it possible, owing to a decreased number of teeth, to increase the impulse journey while maintaining the drop journey. This results in increasing the transmitted energy proportionally.
[0028] The escapement mechanism according to the invention also allows a transmission of energy from the escape-wheel to the pallet through a force whereof the direction is close to that of the direction of movement of the pallet, thereby minimizing energy losses due to friction.
[0029] Another advantage of the escapement mechanism according to the invention lies in the fact that it works as safely as a Swiss lever escapement.
[0030] Another advantage of the escapement mechanism according to the invention lies in the alternating translational movement in a determined direction of the escapement pallet. This makes it possible to produce the escapement pallet perfectly symmetrically at its palette-stones, which interact with the escape-wheel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Other features of the present invention will appear more clearly upon reading the following description, done in reference to the appended drawings, provided as a non-limiting example, in which:
[0032] FIG. 1 shows an example embodiment of an escapement mechanism according to the invention in a first rest phase,
[0033] FIGS. 2 , 3 and 4 illustrate enlargements A, B and D of the escapement mechanism of FIG. 1 ,
[0034] FIG. 5 shows the escapement mechanism according to the invention at the beginning of the unlocking phase,
[0035] FIGS. 6 , 7 and 8 illustrate enlargements A, B and C of the escapement mechanism of FIG. 5 ,
[0036] FIG. 9 illustrates the escapement mechanism according to the invention during the unlocking phase,
[0037] FIGS. 10 , 11 and 12 illustrate enlargements A, B and C of the escapement mechanism of FIG. 9 ,
[0038] FIG. 13 illustrates the escapement mechanism according to the invention during a first impulse phase,
[0039] FIGS. 14 , 15 and 16 illustrate enlargements A, B and C of the escapement mechanism of FIG. 13 ,
[0040] FIG. 17 illustrates the escapement mechanism according to the invention during a second impulse phase,
[0041] FIGS. 18 and 19 illustrate enlargements A and C of the escapement mechanism of FIG. 17 ,
[0042] FIG. 20 illustrates the escapement mechanism according to the invention during a second rest phase,
[0043] FIGS. 21 and 22 illustrate enlargements A and C of the escapement mechanism of FIG. 20 ,
[0044] FIG. 23 illustrates another example embodiment of the escapement mechanism according to the invention in the second impulse phase,
[0045] FIG. 24 shows an alternative embodiment of the escapement mechanism according to the invention in the rest phase, and
[0046] FIG. 25 shows an enlargement A of the escapement mechanism of FIG. 24 .
DETAILED DESCRIPTION OF THE INVENTION
[0047] Structurally and functionally identical elements that are present in several different figures will be given a same numeric or alphanumeric reference.
[0048] FIG. 1 shows an example embodiment of an escapement mechanism according to the invention in a first rest phase. The escapement mechanism comprises an escape-wheel 1 rotating in a direction R around an axis 1 a and an escapement pallet 2 . The escape-wheel 1 advantageously includes an odd number of teeth. That number is for example equal to 7 or 11.
[0049] The escapement pallet 2 includes a body 2 a provided with two rest pallet-stones 3 , 3 ′ and two impulse pallet-stones 4 , 4 ′. The escapement pallet 2 also includes a stick 2 b ending with a fork 5 .
[0050] The escapement mechanism also comprises a plate 6 provided with a pin 7 at its periphery. The plate 6 pivots following an alternating movement around a pivot axis 8 .
[0051] As an example, the body 2 a is a substantially annular piece including two substantially rectilinear central parts 9 and a substantially circular portion 10 at the ends of said central parts, thus defining a geometric shape with an inner space 11 for example having a large axis combined with or parallel to a direction of translation T passing through the center of the escape-wheel 1 and the cooperation zone between the fork 5 and the pin 7 .
[0052] Each of the rest pallet-stones 3 , 3 ′ and each of the impulse pallet-stones are advantageously arranged in a transition zone between a substantially rectilinear central part 9 and a substantially circular portion 10 .
[0053] According to another example embodiment of the escapement mechanism according to the invention, the impulse pallet-stones are arranged on the substantially rectilinear central parts 9 and the rest pallet-stones are arranged on the substantially circular portions 10 .
[0054] The body 2 a has a shape making it possible to the limit the inner space 11 in which the escape-wheel 1 is arranged. The two rest pallet-stones 3 , 3 ′ and the two impulse pallet-stones 4 , 4 ′ protrude in the inner space 11 .
[0055] The plate 6 and the fork 5 are arranged relative to one another so as to impart an alternating translational movement in direction T to the escapement pallet 2 , when the pin 7 cooperates with the fork 5 .
[0056] The fork 5 is for example positioned at the end of the stick 2 b extending substantially in a direction parallel to the direction of translation T. The fork 5 includes input 5 a and output 5 b horns extending orthogonally to said direction of translation T.
[0057] The pivot axis 8 of the plate 6 is advantageously offset relative to the direction of translation T of the body 2 a passing through the center 1 a of the escape-wheel 1 . The fork 5 is offset in an opposite direction relative to said direction of translation T of the body 2 a passing through the center 1 a of said escape-wheel 1 , such that the pin 7 has an alternating rotational movement and cooperates with the input 5 a and output 5 b horns.
[0058] As an alternative embodiment of the mechanism according to the invention, the fork 5 can be placed on the pallet 2 at any other location. The positioning of the plate 6 would then be adapted accordingly.
[0059] The escape-wheel 1 for example includes seven teeth 12 , an example embodiment of which is illustrated enlarged in FIG. 2 . Each tooth 12 includes an end bent in the direction identical to the direction of rotation R. The bent end has a beak 13 and an impulse plane 14 .
[0060] The rest pallet-stones 3 and 3 ′, one example embodiment of which is shown enlarged in FIG. 3 , each include, starting from the free end, an impulse beak 15 , an impulse plane 16 , a rest beak 17 , a rest plane 18 and a return plane 19 .
[0061] The impulse pallet-stones 4 , 4 ′, one example embodiment of which is shown enlarged in FIG. 4 , each include, starting from the free end, an impulse beak 20 , an impulse plane 21 , a first additional plane 22 and a second additional plane 23 so as to delimit a countersink 24 and to have a substantially bent shape. The impulse pallet-stones 4 , 4 ′ are bent in a direction opposite the direction of rotation R of the escape-wheel 1 . The first additional plane 22 connects the impulse plane 21 to the second additional plane 23 .
[0062] As an example, the impulse pallet-stones 4 , 4 ′ and the rest pallet-stones 3 , 3 ′ therefore advantageously have different shapes.
[0063] The impulse planes 16 of the rest pallet-stones 3 , 3 ′ are oriented in a preferred direction coming as close as possible to a direction parallel to the direction of translation T. The impulse planes 21 of the impulse pallet-stones 4 , 4 ′ are oriented in a preferred direction coming as close as possible to a direction orthogonal to the direction of translation T.
[0064] In the rest phase illustrated in FIG. 1 , a tooth 12 bears on the rest pallet-stone 3 . The return plane 19 and the rest plane 18 are inclined such that the escape-wheel 1 and the escapement pallet 2 are blocked in a stable and precise position in which the beak 13 is positioned at the intersection 18 a of the rest plane 18 and the return plane 19 of the rest pallet-stone 3 . So-called “shoulder” positioning is thus obtained.
[0065] In the rest phase, the plate 6 , which is secured to a sprung balance, oscillates freely. In this rest phase, another tooth 12 is housed in the countersink 24 of an impulse pallet-stone 4 , without being in contact with the escapement pallet 2 at any point.
[0066] FIG. 5 shows the escapement mechanism according to the invention at the beginning of the unlocking phase, and FIGS. 6 , 7 and 8 illustrate enlargements A, B and C of the escapement system during this beginning of the unlocking phase.
[0067] The beginning of the unlocking phase corresponds to the entry of the pin 7 of the plate 6 into the fork 5 of the escapement pallet 2 . Reference may for example be made to FIG. 6 . The escapement pallet 2 and the escape-wheel 1 are pulled out of the rest position during the unlocking phase. During this unlocking phase, the beak 13 of the tooth 12 works on the rest plane 18 of the rest pallet-stone 3 , until it reaches the rest beak 17 of said rest pallet-stone 3 .
[0068] During the unlocking phase, the sprung balance delivers sufficient energy to counter the torque of the escape-wheel 1 via the escapement pallet 2 , by imparting a backward movement to said escape-wheel 1 . During this unlocking phase, the other tooth 12 follows the second additional plane 23 of the impulse pallet-stone 4 without touching it.
[0069] FIG. 9 illustrates the escapement system according to the invention during the unlocking phase, and FIGS. 10 , 11 and 12 illustrate enlargements A, B and C of the escapement system during that unlocking phase.
[0070] FIG. 13 illustrates the escapement system according to the invention during a first impulse phase, and FIGS. 14 , 15 and 16 illustrate enlargements A, B and C of the escapement system during that first impulse phase.
[0071] Once the beak 13 of the tooth 12 reaches the rest beak 17 of the rest pallet-stone 3 , the escape-wheel 1 becomes driving and provides the sprung balance, via the escapement pallet 2 and the plate 6 , with the energy necessary to maintain oscillations. This energy is of course greater than that withdrawn during the unlocking phase.
[0072] During this first impulse phase, the beak 13 of the tooth 12 acts on the impulse planes 16 of the rest pallet-stone 3 . The pressure angle of the tooth 12 on the impulse plane being significant, the impulse journey of said tooth 12 on the rest pallet-stone is minimized, but is sufficient for another tooth 12 to take over on the impulse pallet-stone 4 .
[0073] During this first impulse phase on the rest pallet-stone 3 , the other tooth 12 approaches the impulse pallet-stone 4 along the first additional plane 22 of the impulse pallet-stone 4 . Contact is established once the beak 13 of the tooth 12 leaves the rest pallet-stone 3 . One then obtains a second impulse phase.
[0074] FIG. 17 illustrates the escapement system according to the invention during a second impulse phase, and FIGS. 18 and 19 illustrate enlargements A and C of the escapement system during that second impulse phase.
[0075] During this second impulse phase, the impulse is provided by the impulse plane bearing 14 of the other tooth 12 on the impulse plane 21 of the impulse pallet-stone 4 . Reference may for example be made to FIG. 19 . This bearing takes place until the beak 13 of that other tooth 12 leaves the impulse pallet-stone 4 at its impulse beak 20 . FIGS. 17 and 18 also illustrate the cooperation between the pin 7 and the fork 5 .
[0076] The thrust from the escapement pallet 2 on the sprung balance is then interrupted, and the plate 6 freely continues its movement preceding the next escapement function. This then results in a drop phase, in which the escape-wheel 1 , which is momentarily free, finishes its travel with a bearing of another tooth 12 on the other rest pallet-stone 3 ′. There is then another rest phase.
[0077] FIG. 20 illustrates the escapement mechanism according to the invention during a rest phase, and FIGS. 21 and 22 illustrate enlargements A and C of the escapement system during that second rest phase.
[0078] FIG. 23 illustrates another example embodiment of the escapement system according to the invention in the second impulse phase. In this example embodiment, the escape-wheel 1 includes eleven teeth 12 . The escapement mechanism according to the invention is advantageously integrated into a timepiece, of the bracelet watch or other type.
[0079] Furthermore, the body 2 a has straight sectors 2 c favoring the guiding and sliding of the escapement pallet 2 on bearing points secured to the frame of a timepiece, box or platen.
[0080] The escapement mechanism therefore comprises means for guiding the sliding of the body 2 a , arranged to cooperate with bearing elements secured to a frame of a timepiece.
[0081] The timepiece for example comprises bearing element secured to the frame arranged to cooperate with means for guiding the sliding of the body 2 a during its alternating translational movements.
[0082] According to another example embodiment of the escapement mechanism according to the invention, illustrated in FIG. 24 , the shoulder positioning may be replaced by a positioning method using fixed bankings 2 d and 2 e secured to the platen and against which the escapement pallet 2 bears in the rest position. In such an example embodiment, the rest plane 18 would be extended to replace a return plane. The precise positioning of the pallet 2 is then ensured by the bankings 2 d , 2 e , and not by the beak 13 positioned at the intersection of a return plane and a rest plane. Reference may for example be made to FIGS. 24 and 25 .
[0083] According to one preferred example embodiment, the escapement mechanism according to the invention comprises an anti-reversal system. Thus, like a Swiss lever escapement, the fork 5 comprises a dart, not shown, designed to cooperate with a notch of a small plate, not shown, secured to the plate 6 .
[0084] The present invention is of course not limited to the examples explicitly described, but also comprises other embodiments and/or implementations. A described technical feature may thus be replaced by an equivalent technical feature without going beyond the scope of the present invention. | An escapement mechanism for a timepiece, includes an escapement wheel ( 1 ), an escapement anchor ( 2 ) including a body ( 2 a ), and a fork ( 5 ), the body ( 2 a ) including pallets ( 3, 3′, 4, 4 ′) that engage with the escapement wheel ( 1 ), the body ( 2 a ) having a shape that makes it possible to delimit an internal space ( 11 ) for arranging the escapement wheel ( 1 ), the pallets ( 3, 3′, 4, 4 ′) including two rest pallets ( 3, 3 ′) and two impulse pallets ( 4, 4 ′), protruding in the internal space ( 11 ). The mechanism includes a pin ( 7 ) of a roller ( 6 ) that is secured to a regulating device, characterized in that the roller ( 6 ) and the fork ( 5 ) are arranged with respect to one another such as to impart an alternating translation movement with respect to the escapement wheel ( 1 ) to the anchor ( 2 ) when the pin ( 7 ) engages with the fork ( 5 ). | 6 |
This is a continuation of application Ser. No. 09/445,661 U.S. Pat. No. 6,313,141, is a 371 of PCT/US98/14235, filed Jun. 11, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to aminoquinoline derivatives which selectively bind to brain dopamine receptor subtypes. More specifically, it relates to 2-quinolyl(azacycloalkylalkyl)amines and pharmaceutical compositions and preparations containing such compounds. It also relates to the use of such compounds in the treatment or prevention of neuropsychochological disorders such as schizophrenia and other central nervous system diseases.
2. Description of the Related Art
The therapeutic effect of conventional antipsychotics, known as neuroleptics, is generally believed to be exerted through blockade of dopamine receptors. However, neuroleptics are frequently responsible for undesirable extrapyramidal side effects (EPS) and tardive dyskinesias, which are attributed to blockade of D 2 receptors in the striatal region of the brain. The dopamine D 4 receptor subtype has recently been identified. See Nature 350: 610 (Van Tol et al., 1991) and Nature, 347: 146 (Sokoloff et al., 1990) Its unique localization in limbic brain areas and its differential recognition of various antipsychotics suggest that the D 4 receptor plays a role in the etiology of schizophrenia Consequently, selective D 4 antagonists are considered effective antipsychotics free from the neurological side effects displayed by conventional neuroleptics.
U.S. Pat. No. 5,093,333 describes N-substituted-2-aminoquinolines said to be M 1 receptor agonists.
SUMMARY OF THE INVENTION
This invention provides novel compounds of Formula I which interact with dopamine receptor subtypes. A broad aspect of the invention is directed to compounds of Formula I:
wherein:
R 1 , R 2 , and R 3 independently represent hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, hydroxy, amino, mono(C 1 -C 6 ) alkylamino, di(C 1 -C 6 ) alkylamino, cyano, nitro, trifluoromethyl or trifluoromethoxy;
R 6 is hydrogen or C 1 -C 6 alkyl; and
Q represents a substituted azacycloalkylalkyl group of the formula:
where
W is nitrogen, CH or COH;
A represents an alkylene group of from 2-5 carbon atoms optionally substituted with one or more alkyl groups having from one to four carbon atoms; and
T is an aryl or heteroaryl moiety optionally substituted with up to two groups selected from hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, hydroxy, amino, mono(C 1 -C 6 ) alkylamino, di(C 1 -C 6 ) alkylamino, cyano, nitro, trifluoromethyl and trifluoromethoxy.
In yet another aspect, the invention provides pharmaceutical compositions comprising compounds of Formula I.
Since dopamine D 4 receptors are concentrated in the limbic system (Taubes, Science 265: 1034, 1994) which controls cognition and emotion, compounds which interact with these receptors are useful in the treatment of cognitive disorders. Such disorders include cognitive deficits which are a significant component of the negative symptoms (social withdrawal and unresponsiveness) of schizophrenia. In addition, disorders involving memory impairment or attention deficit disorders can be treated with the compounds of this invention. These compounds interact specifically with the dopamine D 4 receptor subtype.
The compounds of the invention demonstrate high affinity and selectivity in binding to the D 4 receptor subtype. The use of the compounds of this invention in methods of treating neuropsychological disorders is predicated on the ability of the compounds to bind selectively to a dopamine receptor subtype, the D 4 receptor. The compounds of the invention can therefore be used in the treatment of schizophrenia, psychotic depression and mania. Other dopamine-mediated diseases such as Parkinsonism and tardive dyskinesias can also be treated directly or indirectly by modulation of D 4 receptors.
Thus, in another aspect, the invention provides methods for treating and/or preventing neuropsychological disorders including, for example, schizophrenia, mania, dementia, depression, anxiety, compulsive behavior, substance abuse, memory impairment, cognitive deficits, Parkinson-like motor disorders and motion disorders related to the use of neuroleptic agents. It also provides methods of treating affective disorders such as Alzheimer's disease and certain movement disorders such as Parkinsonism and dystonia.
The invention further provides methods for treating the extrapyramidal side effects associated with the use of conventional neuroleptic agents. The compounds of the present invention are also useful for the treatment of other disorders which respond to dopaminergic blockade such as substance abuse and obsessive compulsive disorder.
DETAILED DESCRIPTION OF THE INVENTION
In addition to the compounds of Formula I above, the invention encompasses compounds of Formula IA:
wherein:
R 1 , R 2 , R 3 , R 4 and R 5 are the same or different and represent hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, hydroxy, amino, mono(C 1 -C 6 ) alkylamino, di(C 1 -C 6 ) alkylamino, cyano, nitro, trifluoromethyl or trifluoromethoxy;
R 6 is hydrogen or C 1 -C 6 alkyl;
W is nitrogen, COH, or CH;
Y and Z independently represent nitrogen or CH; and
A represents an alkylene group of from 2-5 carbon atoms optionally substituted with one or more alkyl groups having from one to four carbon atoms.
In Formula IA, the dashed segment represents either a single bond resulting in a 3,4 dihydroquinoline; or a double bond resulting in a quinoline.
In the compounds of the invention, “W” preferably represents nitrogen or COH. Preferred “T” groups in Formula I are 6-membered carbocyclic aromatic ring systems having zero, one or two nitrogen atoms. Particularly preferred “T” groups are phenyl, 2-pyridinyl, and 2-pyrimidinyl. The particularly preferred “T” groups are optionally mono- or disubstituted with halogen, C 1 -C 6 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, hydroxy, amino, mono(C 1 -C 6 ) alkylamino, di(C 1 -C 6 ) alkylamino, cyano, nitro, trifluoromethyl or trifluoromethoxy.
Preferred compounds of Formula IA are those where R 6 is hydrogen, methyl or ethyl.
Preferred “T” groups in Formula I are
The invention also provides compounds of Formula II:
wherein:
R 1 , R 2 , R 3 , R 4 and R 5 are the same or different and represent hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, hydroxy, amino, mono(C 1 -C 6 ) alkylamino, di(C 1 -C 6 ) alkylamino, cyano, nitro, trifluoromethyl or trifluoromethoxy;
R 6 is hydrogen or C 1 -C 6 alkyl;
W is nitrogen, COH, or CH;
Y and Z independently represent nitrogen or CH; and
A represents an alkylene group of from 2-5 carbon atoms optionally substituted with one or more alkyl groups having from one to four carbon atoms.
Preferred compounds of Formula II are those where R 6 is hydrogen, methyl or ethyl. Particularly preferred compounds of Formula II are those where
In addition, the invention encompasses compounds of Formula III:
wherein:
R 1 , R 2 , R 3 , R 4 and R 5 are the same or different and represent hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylthio, hydroxy, amino, mono(C 1 -C 6 ) alkylamino, di(C 1 -C 6 ) alkylamino, cyano, nitro, trifluoromethyl or trifluoromethoxy;
R 6 is hydrogen or C 1 -C 6 alkyl;
W is nitrogen, COH, or CH;
Y and Z independently represent nitrogen or CH; and
A represents an alkylene group of from 2-5 carbon atoms optionally substituted with one or more alkyl groups having from one to four carbon atoms.
In preferred compounds of Formula III, R 6 is hydrogen, methyl or ethyl.
In certain situations, compounds of Formula I may contain one or more asymmetric carbon atoms, so that the compounds can exist in different stereoisomeric forms. These compounds can be, for example, racemates or optically active forms. For example, where R 6 in Formula I is a methyl group, the resulting compound can be present as (R) and (S) stereoisomers. In these situations, the single enantiomers, i.e., optically active forms, can be obtained by asymmetric synthesis or by resolution of the racemates. Resolution of the racemates can be accomplished, for example, by conventional methods such as crystallization in the presence of a resolving agent, or chromatography, using, for example a chiral HPLC column.
Representative compounds of the present invention, which are encompassed by Formula I, include, but are not limited to the compounds in Table I and their pharmaceutically acceptable salts. If the compound of the invention is obtained as an acid addition salt, the free base can be obtained by basifying a solution of the acid salt. Conversely, if the product is a free base, an addition salt, particularly a pharmaceutically acceptable addition salt, may be produced by dissolving the free base in a suitable organic solvent and treating the solution with an acid, in accordance with conventional procedures for preparing acid addition salts from base compounds.
Non-toxic pharmaceutically acceptable salts include salts of acids such as hydrochloric, phosphoric, hydrobromic, sulfuric, sulfinic, formic, toluenesulfonic, methanesulfonic, nitric, benzoic, citric, tartaric, maleic, hydroiodic, alkanoic such as, for example, acetic, —HOOC—(CH 2 ) n —COOH where n is 0-4, such as, for example, oxalic (n=0), and the like. Those skilled in the art will recognize a wide variety of non-toxic pharmaceutically acceptable addition salts.
The present invention also encompasses the acylated prodrugs of the compounds of Formula I. Those skilled in the art will recognize various synthetic methodologies which may be employed to prepare non-toxic pharmaceutically acceptable addition salts and acylated prodrugs of the compounds encompassed by Formula I.
By the terms (C 1 -C 6 )alkyl and lower alkyl is meant straight and branched chain alkyl groups having from 1-6 carbon atoms as well as cyclic alkyl groups such as, for example, cyclopropyl, cyclobutyl, or cyclohexyl. Specific examples of such alkyl groups are methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, neopentyl and n-pentyl. Preferred C 1 -C 6 alkyl groups are methyl, ethyl, propyl, butyl or cyclopropylmethyl.
By the terms (C 1 -C 6 )alkoxy and lower alkoxy is meant straight and branched chain alkoxy groups having from 1-6 carbon atoms.
By hydroxy C 1 -C 6 alkyl is meant a C 1 -C 6 alkyl group carrying a terminal hydroxy moiety.
By halogen, halo, or halide is meant fluorine, chlorine, bromine and iodine substituents.
The binding characteristics of compounds of Formula I for the D 4 receptor, expressed in nM, generally range from about 0.5 nanomolar (nM) to about 50 nanomolar (nM). These compounds typically have binding constants for the D 2 receptor of from at least about 100 nM to more than 3000 nM. Thus, the compounds of the invention are generally at least about 3, preferably at least about 5, and most preferably at least about 10 time more selective for the D 4 receptor than the D 2 receptor. Even more preferably, these compounds are at least 20, and more preferably at least 25-50, times more selective for the D 4 receptor than the D 2 receptor.
As noted above, the invention also pertains to the use of compounds of general Formula I in the treatment of neuropsychological disorders.
The compounds of general Formula I may be administered orally, topically, parenterally, by inhalation or spray or rectally in dosage unit formulations containing conventional non-toxic pharmaceutically acceptable carriers, adjuvants and vehicles. The term parenteral as used herein includes subcutaneous injections, intravenous, intramuscular, intrasternal injection or infusion techniques. In addition, there is provided a pharmaceutical formulation comprising a compound of general Formula I and a pharmaceutically acceptable carrier. One or more compounds of general Formula I may be present in association with one or more non-toxic pharmaceutically acceptable carriers and/or diluents and/or adjuvants and if desired other active ingredients. The pharmaceutical compositions containing compounds of general Formula I may be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsion, hard or soft capsules, or syrups or elixirs.
Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, corn starch, or alginic acid; binding agents, for example starch, gelatin or acacia, and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monosterate or glyceryl distearate may be employed.
Formulations for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example peanut oil, liquid paraffin or olive oil.
Aqueous suspensions contain the active materials in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydropropyl methylcellulose, sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example, lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl, or n-propyl p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose or saccharin.
Oily suspensions may be formulated by suspending the active ingredients in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents may be added to provide palatable oral preparations. These compositions may be preserved by the addition of an anti-oxidant such as ascorbic acid.
Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavoring and coloring agents, may also be present.
Pharmaceutical compositions of the invention may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil, for example olive oil or arachis oil, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally-occurring gums, for example gum acacia or gum tragacanth, naturally-occurring phosphatides, for example soy bean, lecithin, and esters or partial esters derived from fatty acids and hexitol, anhydrides, for example sorbitan monoleate, and condensation products of the and partial esters with ethylene oxide, for example polyoxyethylene sorbitan monoleate. The emulsions may also contain sweetening and flavoring agents.
Syrups and elixirs may be formulated with sweetening agents, for example glycerol, propylene glycol, sorbitor or sucrose. Such formulations may also contain a demulcent, a preservative and flavoring and coloring agents. The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleaginous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be sterile injectable solution or suspension in a non-toxic parentally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables.
The compounds of general Formula I may also be administered in the form of suppositories for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials are cocoa butter and polyethylene glycols.
Compounds of general Formula I may be administered parenterally in a sterile medium. The drug, depending on the vehicle and concentration used, can either be suspended or dissolved in the vehicle. Advantageously, adjuvants such as local anesthetics, preservatives and buffering agents can be dissolved in the vehicle.
Dosage levels of the order of from about 0.1 mg to about 140 mg per kilogram of body weight per day are useful in the treatment of the above-indicated conditions (about 0.5 mg to about 7 g per patient per day). The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. Dosage unit forms will generally contain between from about 1 mg to about 500 mg of an active ingredient.
It will be understood, however, that the specific dose level for any particular patient will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, route of administration, and rate of excretion, drug combination and the severity of the particular disease undergoing therapy.
Preparation of 2-Aminoalkylaminoquinolines
The compounds of Formula I, and the pharmaceutically acceptable acid addition salts thereof, may be prepared according to the reactions shown below in Schemes I and II.
wherein R 1 -R 6 , W, Y and Z are as defined above for Formula I.
As shown in Scheme I, a quinoline of general structure IV, possessing an appropriate leaving group (X) at the 2 position, e.g., a halogen or S-methyl group, may be reacted with a primary or secondary amine of general structure V in the presence of a base to afford a compound of Formula I as the desired product. The reaction may be carried out at elevated temperature with or without a solvent. Further, the reaction mixture may also contain an acid scavenger such as diisopropylamine or an inorganic salt such as ammonium chloride.
Where they are not commercially available, the compounds of general structure IV may be prepared by literature procedures or procedures analogous to those described in the literature. Compounds of general structure V are either known or capable of being prepared by the methods known in the art. Those having skill in the art will recognize that the starting materials may be varied and additional steps employed to produce compounds encompassed by the present invention.
Alternatively, compounds of the invention may be prepared according to the reactions shown in Scheme II. Thus, compounds may be prepared from readily available substituted or unsubstituted 4-haloquinoline compounds by allowing them to react with a Wittig reagent. such as an alkyl triphenylphosphonate generated from an alkyltriphenylphosphonium halide; plus a base, such as n-butyllithium in an organic solvent, such as tetrahydrofuran. The resulting 4-alkylquinoline can be converted to a 4-alkyl-2-haloquinoline by treatment with an oxidizing agent, such as m-chloroperbenzoic acid (MCPBA) in an appropriate solvent, such as chloroform, to give the corresponding 4-alkylquinoline N-oxide, followed by reaction with a halogenating agent, such as phosphorus oxychloride to give a 4-alkyl-2-haloquinoline of Formula IVa. Reaction of 2-haloquinoline IVa with amines of Formula V as described above, yields compounds of this invention.
wherein R 1 -R 6 are as defined above, R 1 is alkyl of 1 to 4 carbon atoms, and X is halogen.
The disclosures in this application of all articles and references, including patents, are incorporated herein by reference.
Those having skill in the art will recognize that the starting materials may be varied and additional steps employed to produce compounds encompassed by the present invention. The invention is illustrated further by the following examples which are not to be construed as limiting the invention in scope or spirit to the specific procedures and compounds described in them.
EXAMPLE 1
Preparation of 1-(Pyrimidin-2-yl)-4-(2-aminoethyl)piperazine
A mixture of N-(2-bromoethyl)phthalimide (50.8 g, 0.2 mole), 1-(pyrimidin-2-yl)piperazine (32.8 g, 0.2 mole) and potassium carbonate (55.2 g, 0.4 mole) in dimethyl formamide (400 mL) is heated at 80° C. for 16 hours under a nitrogen atmosphere. After cooling, the reaction mixture is poured into water (1 L) and ether. (1 L). The heterogeneous mixture is then filtered to remove solids and the layers separated. The aqueous layer is further extracted with ether (2×300 mL). The combined organic layers are dried (Na 2 SO 4 ) and concentrated to provide colorless crystals (65 g, 96%, m.p. 132-133° C.).
A portion of the crystals (5 g, 15 mmol) is refluxed under nitrogen in hydrazine hydrate (50 mL) for 7 h. After cooling, the solution is poured into 30% potassium carbonate solution (50 mL) and extracted with methylene chloride. The organic extracts are dried (Na 2 SO 4 ) and concentrated to give a pale yellow oil (3.27 g). This oil is dissolved in methanol (5 mL) and combined with a methanolic solution (10 mL) of fumaric acid (3.66 g). Isopropanol is then added (50 mL) and the resulting mixture concentrated on a hot plate to a volume of 20 mL. Upon cooling, the crystals of fumarate salt are collected (4.77 g, 99%, m.p. 260° C. dec)
EXAMPLE 2
Preparation of (2-(4-pyrimidin-2-ylpiperazinyl)ethyl)-2-quinolylamine (Compound 1)
A solution of 1-(pyrimidin-2-yl)-4-(2-aminoethyl)piperazine (1 g) in xylene (200 mL) is treated with 2-chloroquinoline (1.5 g) and potassium carbonate (2 g). The mixture is then refluxed under N 2 overnight. After cooling, the solution is diluted with diethyl ether (200 mL) and washed with water (3×50 mL). The organic layer is then extracted with an aqueous solution of 10% acetic acid. The aqueous extract is subsequently washed with ether (50 mL), basified with 50% NaOH solution and extracted with ether. The ether layer is dried (K 2 CO 3 ) and evaporated to give the product as an oil (0.47 g). The oil is dissolved in ethanol (20 mL), treated with 48% HBr until acidic and concentrated to a volume of approx. 5 mL. Upon cooling, the off-white crystalline hydrobromide salt is collected by filtration (0.45 g, mp 174-176° C.).
EXAMPLE 3
Preparation of 2-3,4-dihydroquinolyl(2-(4-(2-pyridyl)piperazinyl)ethyl)amine (Compound 2)
A solution of 3,4-dihydro-2(1H)-quinolinone (515 mg) and trimethyloxonium tetrafluoroborate (590 mg) in 50 mL of dry pentene stabilized chloroform is stirred at room temperature overnight. To this mixture is then added 1-(pyridin-2-yl)-4-(2-aminoethyl)piperazine (800 mg) and triethylamine (5 mL). The resultant solution is refluxed overnight under nitrogen. After cooling the solution is concentrated and partitioned between water and ethyl acetate. The organic layer is dried and concentrated to give a brown oil. Purification using preparative thin layer chromatography on silica eluting with 10% CH 3 OH, 89% CHCl 3 , 1% NH 4 OH provides the product as a colorless oil (610 mg, R f =0.51). This material is combined with 420 mg of fumaric acid in 5 mL of methanol. Isopropanol (20 mL) is added and the volume of solution reduced to approximately 5 mL on a hot plate. Upon cooling, the product (700 mg, m.p. 200-202° C.) is collected by filtration.
EXAMPLE 4
Preparation of 2-3,4-dihydroquinolyl(2-(4-(5-fluoropyrimidin-2-yl)piperazinyl)ethyl)amine (Compound 3)
A solution of 3,4-dihydro-2(1H)-quinolinone (515 mg) and trimethyloxonium tetrafluoroborate (590 mg) in 50 mL of dry pentene stabilized chloroform is stirred at room temperature overnight. To this mixture is then added 1-(5-fluoropyrimidin-2-yl)-4-(2-aminoethyl)piperazine (650 mg) and triethylamine (5 mL). The resultant solution is refluxed overnight under nitrogen. After cooling the solution is concentrated and partitioned between water and ethyl acetate. The organic layer is dried and concentrated. Purification using preparative thin layer chromatography on silica eluting with 10% CH 3 OH, 89% CHCl 3 , 1% NH 4 OH affords the product as a yellow oil (410 mg, R f =0.46). This material is combined with 270 mg of fumaric acid in 5 mL of methanol. Isopropanol (20 mL) is added and the solution reduced to a volume of approximately 5 mL on a hot plate. Upon cooling, the product (349 mg, m.p. 170-171° C.) is collected by filtration.
EXAMPLE 5
The following compounds are prepared essentially according to the procedures set forth above in Examples 1 and 2.
(a) (2-(4-pyrimidin-2-ylpiperazinyl)ethyl)-2-quinolylamine hydrobromide (Compound 4, m.p. 174-176° C.)
(b) (3-(4-pyrimidin-2-ylpiperazinyl)propyl)-2-quinolylamine hydrobromide (Compound 5, m.p. 127-128° C.)
(c) (4-(4-pyrimidin-2-ylpiperazinyl)butyl)-2-quinolylamine hydrobromide (Compound 6, m.p. 274-276° C.)
(d) (3-(4-(2-methoxyphenyl)piperazinyl)propyl)-2-quinolylamine fumarate (Compound 7, m.p. 159-160° C.)
(e) (3-(4-(2-pyridyl)piperazinyl)propyl)-2-quinolylamine hydrobromide (Compound 8, m.p. 137-139° C.)
(f) (3-(4-phenylpiperazinyl)propyl)-2-quinolylamine hydrobromide (Compound 9, m.p. 228-229° C.)
(g) (3-(4-(2,3-dimethylphenyl)piperazinyl)propyl)-2-quinolylamine fumarate (Compound 10, m.p. 186-187° C.)
(h) (4methyl(2-quinolyl))(2-(4-pyrimidin-2-ylpiperazinyl)ethyl)amine hydrobromide (Compound 11, m.p. >270° C.)
(i) (4-methyl(2-quinolyl))(3-(4-pyrimidin-2-ylpiperazinyl)propyl)amine hydrobromide (Compound 12, m.p. 255-260° C.)
(j) (4-methyl(2-quinolyl))(4-(4-pyrimidin-2-ylpiperazinyl)butyl)amine hydrobromide (Compound 13, m.p. >260° C.)
(k) (4-methyl(2-quinolyl))(3-(4-(2-methoxyphenyl)piperazinyl)propyl)amine fumarate (Compound 14, m.p. 177-179° C.)
(l) (4-methyl(2-quinolyl))(3-(4-(2-pyridyl)piperazinyl)propyl)amine hydrobromide (Compound 15)
(m) (4-methyl(2-quinolyl))(3-(4-phenylpiperazinyl)propyl)amine fumarate (Compound 16, m.p. 208-209° C.)
(n) (4-methyl(2-quinolyl))(3-(4-(2,3-dimethylphenyl)piperazinyl)propylamine fumarate (Compound 17, m.p 159-160° C.)
(o) (2-(4-(5-fluoropyrimidin-2-yl)piperazinyl)ethyl)-2-quinolylamine hydrobromide (Compound 18, m.p. 150-151° C.)
(p) (4-methyl(2-quinolyl))(2-(4-(5-fluoropyrimidin-2-yl)piperazinyl)ethyl)amine hydrobromide (Compound 19, m.p. 250-253° C.)
(q) (4-(4-pyrimidin-2-ylpiperazinyl)butyl)-2-quinolylamine (compound 20)
(r) (3-(4-(2,3-dimethylphenyl)piperazinyl)propyl)-2-quinolylamine (Compound 21)
(s) (4-methyl(2-quinolyl))(3-(4-(pyrimidin-2-yl)piperazinyl)propyl)amine (Compound 22)
EXAMPLE 6
The following compounds are prepared essentially according to the procedures set forth above in Examples 3 and 4.
(a) 2-3,4-dihydroquinolyl(2-(4-(pyrimidin-2-yl)piperazinyl)ethyl)amine fumarate (Compound 20, m.p. 217-218° C.)
(b) 2-3,4-dihydroquinolyl(3-(4-(pyrimidin-2-yl)piperazinyl)propyl)amine fumarate (Compound 21, m.p. 194-195° C.)
(c) 2-3,4-dihydroquinolyl(4-(4-(5-fluoropyrimidin-2-yl)piperazinyl)butyl)amine hydrobromide (Compound 22, m.p. 279-280° C., dec)
(d) 2-3,4-dihydroquinolyl(2-(4-(5-fluoropyrimidin-2-yl)piperazinyl)ethyl)amine fumarate (Compound 23, m.p. 200-201° C.)
(e) 2-3,4-dihydroquinolyl(3-(4-(5-fluoropyrimidin-2-yl)piperazinyl)propyl)amine fumarate (Compound 24, m.p. 173-176° C.)
(f) 2-3,4-dihydroquinolyl(4-(4-(5-fluoropyrimidin-2-yl)piperazinyl)butyl)amine fumarate (Compound 25, m.p. 182-183° C.)
(g) 2-3,4-dihydroquinolyl(4-(4-(5-methylpyrimidin-2-yl)piperazinyl)butyl)amine fumarate (Compound 26, m.p. 253-254° C.)
(h) 2-3,4-dihydroquinolyl(2-(4-(2-pyridyl)piperazinyl)ethyl)amine fumarate (Compound 27)
(i) 2-3,4-dihydroquinolyl(3-(4-(2-pyridyl)piperazinyl)propyl)amine fumarate (Compound 28, m.p. 190-191° C.)
(j) 2-3,4-dihydroquinolyl(4-(4-(2-pyridyl)piperazinyl)butyl)amine fumarate (Compound 29, 154-155° C.)
(k) 1-(3-(2-3,4-dihydroquinolylamino)propyl)-4-phenylpiperidin-4-ol hydrobromide (Compound 30, m.p. 247° C.)
(l) 4-(4-chlorophenyl)- 1 -(3-(2-3,4-dihydroquinolylamino)propyl)piperidin-4-ol hydrobromide (Compound 31, m.p. >260° C.)
EXAMPLE 7
The pharmaceutical utility of compounds of this invention is indicated by the assays for dopamine receptor subtype affinity described below.
Representative examples of 2-aminoalkylaminoquinolines according to the invention and representative corresponding biological activities are shown in Table 1 below. The number below each compound is its compound number. Each of these compounds may be prepared according to the reactions described above and shown in Scheme I.
Compounds 1-4 in Table 1 have the following general formula A:
where R 3 and R 7 are defined in the table.
Compounds 5-6 in Table 1 have the following general formula B:
where R 3 and R 7 are defined in the table.
Assay for D 2 and D 4 Receptor Binding Activity
Pellets of COS cells containing recombinantly produced D 2 or D 4 receptors from African Green monkey were used for the assays. The sample is homogenized in 100 volumes (w/vol) of 0.05 M Tris HCl buffer at 4° C. and pH 7.4. The sample is then centrifuged at 30,000×g and resuspended and rehomogenized. The sample is then centrifuged as described and the final tissue sample is frozen until use. The tissue is resuspended 1:20 (wt/vol) in 0.05 M Tris HCl buffer containing 100 mM NaCl.
Incubations are carried out at 48° C. and contain 0.4 ml of tissue sample, 0.5 nM 3 H-YM 09151-2 and the compound of interest in a total incubation of 1.0 ml. Nonspecific binding is defined as that binding found in the presence of 1 mM spiperone; without further additions, nonspecific binding is less than 20% of total binding. Binding characteristics of various compounds of the invention for D 2 and D 4 receptor subtypes are shown in Table 1 for rat striatal homogenates.
Various compounds of the invention were also evaluated in M 1 and M 2 Muscarinic subtype assays essentially as set forth in U.S. Pat. No. 5,093,333. The activity of the compounds is shown in Table 1.
TABLE 1
Compound
D 2
D 4
M 1
M 2
Number
R 1
R 7
K i (nM)
K 1 (nM)
(nM)
(nM)
1
H
2720
10
264
299
11
CH 3
10
178
246
21
H
>100
22
22
CH 3
3300
10
2
H
>100
30
3
H
8
128
144
Various compounds disclosed in U.S. Pat. No. 5,093,333 (Saab) were evaluated in the D 4 , M 1 , and M 2 receptor assays as described above. The activity of these compounds is shown below in Table 2.
Saab Example
No.
Structure
M 1
M 2
D 4
1
1200
2500
>1000
2
2500
11600
>1000
3
600
2800
>1000
7
1300
20000
>1000
The invention and the manner and process of making and using it, are now described in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains, to make and use the same. It is to be understood that the foregoing describes preferred embodiments of the present invention and that modifications may be made therein without departing from the spirit or scope of the present invention as set forth in the claims. To particularly point out and distinctly claim the subject matter regarded as invention, the following claims conclude this specification. | Disclosed are compounds of the formula:
or the pharmaceutically acceptable salts thereof wherein:
R 1 , R 2 , and R 3 are as defined herein;
R 6 is hydrogen or C 1 -C 6 alkyl; and
Q represents a substituted azacycloalkylalkyl group,
which compounds are useful in treating psychotic disorders such as schizophrenia and other central nervous system diseases. | 0 |
BACKGROUND OF THE INVENTION
[0001] The invention relates in general to barrier movement operators and in particular to a jack shaft garage door operator having a sensing apparatus for preventing cable associated with a pull-up cable drum from becoming slack during the operation of the door and for providing a positive door locking system.
[0002] One of the problems associated with jack shaft garage door operators is that while they are compact and may be conveniently used in garages which have little overhead room, they may present problems to the owners of the garage in that the cable may be payed out allowing the door to close under its own weight and if the door stalls or if the cable pay out drum rotates too far, the tension in the cable will drop and the cable may come off the drum necessitating a visit from a repairman. In addition, the jack shaft garage door operator does not provide any secure locking facility other than a lock at the bottom of the door, which may be tampered with by a burglar. If the door is not locked by some other means, the bottom lock may be forced or damaged and the door can be lifted open and the garage entered by an intruder.
[0003] U.S. Pat. No. 3,785,809 discloses a door operator having a winch member built into a tilting door and movable with it. A cable is attached to a wall member supporting the door and another end of the cable is connected to an extensible arm.
[0004] U.S. Pat. No. 2,185,828 discloses a catch for stopping a door from falling in the event that a sustaining cable or a counterbalance fails or breaks.
[0005] U.S. Pat. No. 4,385,471 discloses a door including a stopping member having a clip connection 29 which engages a cable. If the cable breaks, as shown in FIG. 4, the arm 27 rotates outwardly bringing a cam dog 26 having a plurality of teeth 32 into locking engagement with a roller 13 a to prevent the roller 13 a from moving, thereby suspending the door in position.
[0006] U.S. Pat. No. 4,520,591 to Calvagno discloses a system that is mechanically responsive to a break in a cable to prevent a door from falling.
[0007] French Patent No. 2634-815-A includes an “antidrop” safety mechanism having a cam plate 21 on either side of the door equipped with a convex toothed edge to engage a bracket in case of door suspension failure. None of the aforementioned documents teach or disclose solutions for preventing a door from being opened or from stopping an operation of a garage door operator to cause it to reverse to take up cable which may have inadvertently been payed off a cable drum of a jack shaft door operator.
[0008] What is needed is an improved barrier movement operator that avoids unwanted problems with the cable coming off the drum and provides security for the user.
SUMMARY OF THE INVENTION
[0009] A jack shaft garage door operator is useful for opening and closing a movable barrier such as a garage door. The jack shaft garage door operator embodying the present invention includes a drive unit having an electric motor therein for driving a torsion shaft sometimes called a jack shaft. The jack shaft is mounted above a door opening and usually has coupled to it a spring, or the like, for providing a restoring force to the jack shaft to help raise the door and to support a portion of the weight of the door that is not supported by the L-shaped rails that a door usually rides in. A pull-up cable drum is connected to the jack shaft to be rotated thereby and has a multi-strand steel pull-up cable connected thereto that may be payed out to lower a door or wound up to raise the door. The pull-up cable is typically connected to a bottom portion of the door and, when wound up, will cause the door to rise along vertical portions of L-shaped rails. A cable tension sensing apparatus is mounted on a wall having a door opening. The cable tension sensing apparatus includes cable guide to retain the cable a substantially fixed distance from the wall and a spring driven cable follower which urges against the cable extending between the drum periphery and the cable guide. An alerting switch is connected to the cable follower and sends a signal indicating loss of cable tension when the cable follower moves beyond a predetermined distance. Additionally, the movement of the cable follower moves a door blocking arrangement to a position to block movement of the door when being raised without use of the motor.
[0010] In the event that the cable is inadvertently payed out, for instance, by the door having reached the bottom of its travel and the operator continuing to run, the cable follower is allowed to move away from the wall by reduced tension (slack) in the cable and moves far enough that the alerting switch operates to generate a signal to which the operator responds by reversing the motor to raise the door. The garage door operator may otherwise be a conventional jack shaft garage door operator. The cable tension sensing apparatus prevents the cable from coming off the cable drum. In addition, a door stop for preventing the garage door from opening is attached to an upper panel of the garage door and, when in the closed position, is beneath the cable tension sensing apparatus when the door is pulled downwardly by full tension on the cable. When the cable follower moves as tension lessens in the cable, a sliding member is moved away from the wall above the door. If the door is attempted to be breached, for instance by an intruder attempting to lift the door, the cable becomes slack allowing the sliding member to come out from the wall so that it then engages compressionally a stop plate on the garage door thereby preventing further upward motion of the garage door.
[0011] It is an aspect of the present invention to provide a jack shaft garage door operator having a cable tension sensor for providing door operator actions reversal to prevent cable paying off a cable drum.
[0012] It is another aspect of the present invention to provide a jack shaft garage door operator having a door opening block adapted to engage a sliding member to prevent a door from being forced open.
[0013] Other advantages of the invention will become obvious to one of ordinary skill in the art upon a perusal of the following specification and claims in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1 is a plan view of a portion of a garage having a garage door in a closed position with a jack shaft garage door operator associated therewith;
[0015] [0015]FIG. 2 is a perspective view showing details of a portion of the jack shaft garage door operator shown in FIG. 1;
[0016] [0016]FIG. 3 is a side view of a portion of the jack shaft garage door operator;
[0017] [0017]FIG. 4 is a side view, showing a cable tensioning member of the jack shaft garage door operator positioned to take up slack in a pull-up cable;
[0018] [0018]FIGS. 5 a - 5 b is a circuit diagram showing portions of the electrical safety and control circuitry of the garage door opener;
[0019] [0019]FIG. 6 is a perspective view of a frame used in the embodiment;
[0020] [0020]FIG. 7 is a perspective view of a sliding member and door stop of the embodiment;
[0021] [0021]FIG. 8 is a perspective view of a portion of the pivot member and tension sensor; and
[0022] [0022]FIG. 9 is a perspective view of a tension sensor disabling apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] Referring now to the drawings and especially to FIG. 1, a jack shaft garage door operator embodying the present invention and generally identified by numeral 10 is shown therein. The jack shaft garage door operator 10 is mounted on a garage wall 12 near a garage door opening which has associated with it a movable multiple panel garage door 16 .
[0024] The jack shaft garage door operator 10 includes a drive unit 20 having a motor 25 (FIG. 5 b ) which is connected by a chain drive system 21 to a jack shaft 22 . The motor 25 of drive unit 20 is energized in a well known manner to rotate the jack shaft 22 . Cable drums 24 and 24 ′ are mounted on the jack shaft 22 to be turned and respective pull-up cables 26 and 26 ′ are wound around the cable drums 24 and 24 ′ to be pulled upwardly. A cable tension assembly shown at 28 is mounted on the wall 12 of the garage immediately above the door 16 adjacent the jack shaft 22 .
[0025] The garage door 16 is a multiple paneled door consisting of a plurality of rectangular panels 40 , 42 , 44 and 46 . The panels 40 and 42 are connected by a plurality of hinges 50 . Panels 42 and 44 are connected by a plurality of hinges 52 . Panels 44 and 46 are connected by a plurality of hinges 54 . The door is carried on a plurality of rollers in a pair of L-shaped tracks 60 , when the door 16 is lowered, the jack shaft 22 is rotated to pay out the cables 26 and 26 ′ from the pull-up cable drums 24 and 24 ′.
[0026] Drive unit 20 includes a controller 27 shown in detail in FIG. 5 a - 5 b which responds to input signals to control the raising and lowering of door 16 by selectively stopping or energizing up and down rotation of motor 25 . Controller 27 responds to standard input signals in a known manner to raise and lower the door. Pushing a button 23 when the door is open or closed will cause a processor 31 of controller 27 to energize the motor 25 to move the door to the other state. Similarly, receipt of a properly encoded signal from a remote transmitter 29 (FIG. 1) at a receiver 33 will result in the processor 31 causing the door to open or close.
[0027] The garage door operator includes infrared obstruction sensor apparatus comprising a transmitter 37 mounted on one side of the door and a receiver 35 mounted on the opposite side of the door. The transmitter 37 is aimed at the receiver 35 and transmits a recurring series of light pulses. The receiver 35 receives the light pulses and generates a series of electrical pulses on a conductor pair 39 connected to the controller 27 . It should be mentioned that the controller 27 also provides DC power to the transmitter 37 and receiver 35 via the conductor pair 39 to power their operation. Whenever the transmitted light beams from transmitter 37 to receiver 35 are blocked, the pulses on conductor 39 are terminated by receiver 35 . Processor 31 senses the stoppage of pulses and, when the door is traveling downward, the processor controls the motor 25 to stop and then to rotate to raise the door. Thus the door is kept from striking whatever is in the doorway blocking the light beam. The DC voltage which powers the operation of transmitter 37 is connected, in part, to transmitter 37 via a normally open contact 30 of a switch 32 . The closed state of contact 30 is maintained when tension is present in cable 26 . As is discussed later herein, when the tension in cable 26 decreases switch contact 30 opens and, the transmitter stops transmitting light pulses causing the pulses on conductors 39 to stop. As in the case of an optical obstruction, controller 31 responds to the stoppage of pulses on conductors 39 by raising the door when the door was traveling down.
[0028] [0028]FIG. 2 is a perspective view of cable tension assembly 28 as mounted to wall 12 near cable drum 24 . Cable tension assembly 28 includes a cable guide roller 71 which is rotatably mounted to wall 12 in a roller frame 72 . Cable 26 passes between roller 71 and wall 12 . FIG. 3 is a plan view of the cable tension assembly as viewed outwardly from the center of the door 16 . As shown in FIG. 3, roller 71 is rotatably held by assembly 72 at a distance from wall 12 which is substantially equal to the distance between wall 12 and the perimeter 73 of drum 24 . Thus, the perimeter 73 of drum 24 and the roller 71 keep cable running substantially parallel to the surface of wall 12 when tension is present in the cable 26 .
[0029] Roller holding assembly 72 is a portion of a frame 75 (FIG. 6) which supports portions of the tension assembly 28 . Frame 75 includes a portion 77 which is substantially normal to the surface of wall 12 and includes a slot 79 which is also normal to wall 12 . Cable tension assembly 28 also includes a sliding member 81 (FIG. 7), which is slidably connected to frame 75 at slot 79 by means of a nylon slide 85 . More specifically a pair of screws 86 secure nylon slide 85 to a front face of portion 77 by means of two holes 87 in sliding member 81 . After such attachment, sliding member 81 on one side of portion 77 and nylon slide 85 on the other are free to move normally to wall 12 while trapped in slot 79 . A doorstop 83 may also be attached to sliding member 81 to stop the raising of door 16 by means other than motor 25 .
[0030] A cable tension sensing pivot member 91 is used to sense the tension in cable 26 . Pivot member 91 is slidably mounted to jack shaft 22 and is free to rotate about the longitudinal axis of jack shaft 22 as represented by accurate arrow 95 (FIG. 3). Pivot member 91 includes a cable sensor 97 which, after mounting pivot member 91 , is placed between cable 26 and wall 12 . Pivot member 91 includes a protrusion 98 which after assembly of the cable tension apparatus 28 is slidably inserted into a slot 82 of sliding member 81 . Rotational force is applied to pivot member 91 by a torsion spring 101 which is disposed between protrusion 98 and a tab 103 of frame 75 . By the operation of spring 101 the pivot member 91 is urged to rotate in a clockwise direction as shown in FIG. 3.
[0031] It will be remembered that DC voltage is applied to the infrared transmitter 37 via the normally open contact 30 (FIG. 5 a ) of a switch 32 . In FIG. 2, switch 32 is shown mounted to frame 75 and with a switch lever 107 disposed between a shelf 109 of nylon sliding member 85 and wall 12 . When tension is present in cable 26 (FIG. 3) the cable tension follower 97 is urged against the force of spring 101 and maintained in a position shown in FIG. 3. In the “tensioned” position of FIG. 3 the switch lever 107 is held by sliding member 85 and switch contact 30 of switch 32 is kept in the closed state. Thus, when tension is present in cable 26 the infrared obstruction detection system operates in a normal, well known manner.
[0032] Alternatively, FIG. 4 shows the situation when the cable is not under tension such as would occur if the door 16 became stuck when being lowered or the motor continued to run after reaching the down limit. Without the counter force of cable tension on cable guide 97 , spring 101 causes pivot member 91 to rotate clockwise to a position shown in FIG. 4. As pivot member 91 rotates, pin 98 moves within slot 82 causing sliding member 75 to move away from wall 12 . The movement of sliding member 75 raises the switch lever 107 until switch contact 30 of switch 32 assumes its normally open state. The opening of switch contact 30 removes DC voltage from transmitter 37 which results in controller 27 sensing the absence of pulses on conductor 39 . As described above, the controller 27 responds to the absence of pulses by controlling motor to raise door 16 . When motor 25 begins to turn the jack shaft 22 to raise the door, tension will be restored in cable 26 and the configuration shown in FIG. 3 will again be achieved.
[0033] The raising of door 16 in response to a lack of cable tension occurs only when the door 16 is being lowered by motor 25 . When the door is in the lowered/closed state, processor 31 does not respond to the removal of cable tension by energizing motor 25 to raise the door. This occurs because processor 31 is programmed to perform a remedial opening of the door 16 only when the door is being closed under the control of controller 27 .
[0034] Should someone, such as a burglar, attempt to raise a door 16 , which is in the closed state, the sliding member 81 and a door stop extension 83 provide protection. When the door is closed and an attempt to raise it is made, the cable 26 will go slack as shown in FIG. 4. The slack cable will result in sliding member 81 moving away from the wall 12 . Affixed to sliding member 81 is a door stop 83 which moves translationally along with sliding member 81 . A spacer block 111 (FIG. 1) is attached to the inside of the top panel 40 of the door 16 and strikes the door stop 83 which stops the door from further movement. Alternatively, when the door is being raised by the motor, tension is present in the cable and, as shown in FIG. 3, the door stop is retained near wall 12 . The block 111 will freely pass the door stop 83 when it is held near the wall 12 .
[0035] Under certain conditions, such as the door spring 120 breaking or coming loose, the door 16 may be closed and tension is removed from the cable 26 . This might result in a blocked door as represented in FIG. 4. To prevent such, an emergency release control is provided whereby a person inside the garage can raise the door. The release control includes a release cable or rope 123 and handle 121 as represented in FIGS. 1 and 9. In FIG. 9 the cable tension assembly 28 has been simplified for ease of understanding. When the emergency release is present, the protrusion 98 is extended and is shown as 98 ′ in FIG. 9. Also the spring holding member 103 ′ is formed to more easily allow the rope or cable 123 to slide passed.
[0036] The emergency release (FIG. 9) includes a cable or rope 123 connected to a user operated handle 121 at a free end and running up through guides 125 which are affixed to the wall 12 . The guides 125 retain the rope 123 in place and allow a 180° change in the rope's direction of movement. Rope 123 extends between the spring retainer 103 ′ and the wall 12 and passes over protrusion 98 ′ away from wall 12 . The rope 123 is then tied to an anchor 126 . When the door block is to be manually controlled, an operator pulls downwardly on handle 121 which tightens cable 123 and moves protrusion 98 ′ and sliding member 81 back toward the wall 12 freeing tube door 16 to be raised. Advantageously, rope 123 may also be attached to a clutch in opener 20 to release the motor 25 from the chain assembly 21 to ease the manual raising of the door.
[0037] The preceding description is intended to be illustrative of the principles of the invention and modifications can be made to the embodiment and still be within the scope of the invention recited in the appended claims. For example, the torsion spring 120 of the preceding embodiment could be replaced by a counter weight. Further, the distance between the wall and cable tension assembly might be varied by the use of a shim to avoid the use of member 111 attached to door 16 . | A cable tension sensing apparatus is mounted on a wall having a door opening. The jack shaft garage door operator includes a drive unit having an electric motor for driving a jack shaft mounted above a door opening. A pull-up cable drum is connected to the jack shaft and has a multi-strand steel pull-up cable that may be payed out to lower a door or wound up to raise the door. The cable tension sensing apparatus includes a cable guide to retain the cable a substantially fixed distance from the wall and a spring driven cable follower which urges against the cable extending between the drum periphery and the cable guide. An alerting switch is connected to the cable follower and sends a signal indicating loss of cable tension when the cable follower moves beyond a predetermined distance. Additionally, the movement of the cable follower moves a door blocking arrangement to a position to block movement of the door when being raised without use of the motor. | 4 |
BACKGROUND OF THE INVENTION
This invention relates to a process for sintering or reaction sintering ceramic or refractory materials using plasma heated gases.
In practice, many ceramic or refractory materials, such as those consisting of alumina and silica, are sintered in tunnel or periodic kilns which are fired by energy released from the combustion of fossil fuels with air or oxygen. If the ceramic or refractory material can be exposed to air and/or the products of combustion, then the kiln may be directly fired, in which case, the heating and utilization of energy may be reasonably efficient. However, for certain ceramic materials, such as the carbides, nitrides and borides, the firing must be done in the absence of oxygen or oxygen-bearing gases, including water and carbon dioxide, to prevent formation of oxides, which may have undesirable physical or chemical properties. Under such conditions, fossil fuel-fired furnaces may be used but the ceramic or refractory materials must be kept in a controlled environment isolated from the combustion products of the fuel. Because the ceramic or refractory materials must be heated in a retort, the heating is indirect, inefficient and slow. On a commercial scale such a process, using a tunnel kiln, for example, requires about 70-90 hours (including the cooling cycle).
Electric kilns are also used to sinter ceramic or refractory materials under controlled atmospheres, but also tend to be energy inefficient and slow. In the case of a kiln equipped with heating elements such as graphite electrodes, the voltage can be controlled and the kiln can be heated to fairly high temperatures, yet there are several disadvantages: (1) The heating elements have a limited size, complex shape and must be kept under a strictly controlled atmosphere to maintain a long life; and, (2) Furnace size is limited and it is difficult to achieve a uniform temperature in this type of kiln because only the heating elements are the source of the radiant heat. Because of this radiant heat transfer, as well as a size limit for heating elements, the kiln has a limited productivity and a poor energy efficiency.
Conventional processes, in general, require long retention times resulting in poor energy utilization, excessive furnace gas consumption and high maintenance costs.
In the sintering or reaction sintering of ceramic or refractory materials, the required reaction temperature of the furnace is usually less than 2500° C. However, the average temperature of gases heated through a plasma arc column is above 7000° C.; thus, plasma technology has previously been applied only to fusion of high temperature materials and not to sintering or reaction sintering. In order to use plasma heated gases at a lower furnace temperature, they can be mixed with secondary gases. Prior art plasma systems for mixing plasma heated gases and secondary gases generally employ radial injection of the secondary gases into the plasma gas and single rather than multiple plasma torches. In a furnace disclosed in U.S. Pat. No. 3,935,371 by Camacho et al. entitled "Plasma Heated Batch-Type Annealing Furnace", the plasma torch and reactant gas inlet are positioned on the bottom of the furnace and flow in the same direction.
SUMMARY OF THE INVENTION
The present invention relates to a sintering process for ceramic or refractory materials comprising tangentially injecting a secondary gas stream into a plasma arc gas stream; and, the resulting hot plasma gas is fired directly through a furnace injection port.
In accordance with the process of the present invention, when the secondary gas stream is injected tangentially into the plasma arc stream, a swirl effect is created wherein the cold gas surrounds the hot plasma core, resulting in improved energy efficiency.
Preferably, in accordance with the present invention, more than one plasma torch is used and they are postitioned asymmetrically through ports in the furnace. For the same amount of power, two torches are more efficient than a single torch in creating the maximum turbulence inside the furnace.
A plasma arc system, in accordance with the present invention, may be retrofitted to conventional furnaces, or to a furnace which has been specifically constructed for plasma gases. The plasma arc system of the present invention may be used in either continuous or periodic (batch) processes. In a preferred form of the present invention, using a continuous process, several sets of plasma arc torches are positioned along the heating zone and the soaking zone. To create maximum turbulence within the furnace, the mixed plasma and secondary gas streams are injected perpendicularly to or slightly countercurrent to the process gas stream flow.
Use of plasma arc torches, in accordance with the process of the present invention, results in increased reaction rates because of a higher heat transfer; and from an increased chemical reactivity when the sintering involves reaction of the plasma gas with the ceramic or refractory materials. Higher reaction rates result in higher energy efficiencies, lower retention times, and higher kiln productivities. In addition, a superior corrosion-resistant product is produced by the process of the present invention.
Accordingly, it is an object of the present invention to provide a process for sintering ceramic or refractory materials which is inexpensive, efficient, and can be applied to continuous or periodic kilns.
It is a further object of the present invention to provide a process for sintering ceramic or refractory materials which, because of good convective heat transfer throughout the entire furnace, achieves high kiln productivity, a uniform temperature distribution in the kiln, and a significant reduction of the retention time required for ceramic or refractory materials.
It is yet another object of this invention to provide a process for sintering ceramic or refractory materials which results in a simple kiln design, with good reliability and control of the furnace.
It is yet a further object of the present invention to provide a process for sintering ceramic or refractory materials which results in consistent, uniform and superior quality products.
It is a further object of this invention to provide a process for mixing plasma gases that has a decreased energy loss to cooling water, prevents hydrodynamic interference of the secondary gas stream with the primary plasma arc column gas stream, and results in improved energy efficiency.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description to follow, taken in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a plasma gas fired batch furnace;
FIG. 2 is a perspective view of a plasma gas fired continuous furance; and,
FIGS. 3 and 4 are diagrams showing the effect of tangential injection of a secondary gas.
DESCRIPTION OF THE PREFERRED EMBODIMENT
This invention relates to a process for sintering or reaction sintering ceramic or refractory materials in which the improvement is connected with the injection of a plasma gas combined with a secondary gas stream, from at least two plasma arc torches, directly into at least two gas ports of a furnace. The invention includes tangential injection of the secondary gas into the plasma gas within the torch. The torch with these combined gases is positioned through ports to cause the combined gases to flow in a direction which is perpendicular to the process gas flow.
The invention may be used to great advantage in practicing the process set forth in U.S. patent application Ser. No. 403,938 filed Aug. 2, 1982 now abandoned, entitled "A Sintering Process for Refractory Articles Using Direct-Heated Gases," the teachings of which are incorporated herein by reference.
Plasma arc fired gases differ greatly from ordinary furnace heated gases in that they contain electrically charged particles capable of transferring electricity and heat, and become ionized; or as in the case of nitrogen, become dissociated and highly reactive. These phenomena greatly increase the reaction rates for bonding ceramic or refractory materials. Nitrogen, for example, which dissociates at around 5000° C. and 1 atmosphere pressure, would not dissociate under the normal furnace sintering conditions of around 1500° C.-2000° C. Even if a furnace could reach the high dissociation temperature of nitrogen, it would be undesirable for the ceramic or refractory materials to be at this high temperature because bonds or materials might decompose. Thus, a plasma gas can be superheated to effect ionization or dissociation, while the ceramic or refractory materials can be directly heated by this preheated gas to a much lower temperature. Nitrogen plasma gas dissociates into a highly reactive mixture of N 2 -molecules, N-atoms, N + -ions and electrons. Argon, on the other hand, ionizes rather than dissociates when used with a plasma arc. Any plasma gas may be used in accordance with the present invention, depending upon sintering requirements.
Use of plasma arc torches increases the reaction rate because of a higher heat tranfer rate, in addition to increasing the chemical reactivity as in the case of using nitrogen plasma gas for a nitriding reaction. An increased reaction rate results in a lower retention time in the furnace and a higher kiln productivity. Processing in accordance with the present invention requires only about one-fifth of the time required for conventional processing.
The average temperature of gases heated through a plasma arc column or torch is above 7000° C., whereas the average operating temperature of a sintering furnace is around 1500° C.-2500° C. Thus, blending a plasma arc gas stream with a secondary gas stream is required to achieve the lower sintering temperatures.
FIG. 1 shows schematically a plasma gas fired batch type furnace. In this the two plasma torches are located one in front and one in rear to create maximum turbulence. In a continuous furnace the hot plasma gas will be introduced in the heating and reaction zones, as shown in FIG. 2. In this furnace the solids move counter-current to gas flow. FIGS. 3 and 4 show the tangential injection of the secondary gas in the water cooled mixing chamber. This results in the hot plasma gas in the core being shielded by the secondary cooler gas thereby improving energy efficiency.
In accordance with the present invention, the injection of a secondary gas into the plasma arc gas stream, in a tangential fashion as shown in FIG. 3, provides the best mixing of the two gas streams. Tangential injection of the secondary gas stream together with an existing pressure drop creates a swirl effect wherein the cold gas envelops the hot plasma core. FIG. 3 shows the secondary gas stream being injected into four sites; however, more than four or fewer than four sites may be utilized to create the swirl effect.
This tangential design of the present invention yields higher efficiencies when compared to radial injection. Almost all of the mixing of the two streams takes place as the gases leave the torch and enter the furnace. Improved energy efficiency results from the cold gas stream enveloping the hot plasma core stream inside the torch chamber, thus preventing hydrodynamic interference of the secondary gas stream with the plasma arc gas stream.
In the preferred form of this invention, more than one plasma torch is used and they are positioned asymmetrically through ports in the furnace to create a uniform temperature distribution and maximum turbulence in the furnace for convective heat transfer. For the same amount of power, two torches or more are more effective than a single torch. In the case of two plasma torches positioned through ports in a rectangular-shaped furnace, for example, one torch could be positioned at the lower front left side of the furnace, and the other plasma torch could be positioned at the lower back right side of the furnace, to achieve this asymmetric positioning. In the case of a continuous tunnel kiln, two sets of plasma torches could be asymmetrically positioned; one set along the heating zone, and one set along the soaking zone.
Plasma arc systems in accordance with the present invention may be fitted to conventional periodic (batch) kilns or continuous kilns, such as tunnel or push-type kilns. Thus, the process of the present invention may be operated as either a batch process or as a continuous process. The furnace used in accordance with the present invention may be specifically constructed for the purpose of the present invention, or as noted above, may be any conventional furnace including batch and continuous type furnaces, modified by using plasma arc torches instead of fuel burners or electrodes.
In a preferred form of this invention, using a continuous process, dried green ceramic or refractory materials continuously enter a gas tight kiln from a purging chamber. A car or setter plate travels through heating, soaking and cooling zones at a constant speed. The kiln is operated with a hermetic seal. Plasma gas at a given volumetric rate, is flowed perpendicular to the product movement and process gas stream. Plasma torches located at the heating and soaking zones inject plasma gas at high temperatures into the kiln depending on energy requirements. Heated plasma gases enter the preheat zone and heat the incoming green ceramic or refractory materials. The exit plasma gas temperature is controlled to entrain most of the volatile matters into a condenser or a scrubber. Cleaned gas is then recycled to the kiln.
The invention is further illustrated by the following non-limiting examples in which silicon carbide (Refrax 20®) was formed into green refractory bricks and placed into a furnace for sintering by the reaction of free elemental silicon in the bricks with plasma nitrogen gas to form silicon nitride (Si 3 N 4 ) bonds. The temperature of the plasma heated nitrogen was at 3000°-3500° C. and the heating rate was 250°-350° C./hr.
The inner dimensions of the furnace were 24"×22"×18", making a total working volume of 5.5 ft 3 . The furnace had an interior lining of 1" thick silicon carbide tile, Carbofrax®, to withstand severe thermal cycles as well as a silicon atmosphere. The tile was backed by 2 inches of Saffil® blanket, 3 inches of Fiberfrax® (8 lbs/ft 3 ) and 2 inches of Fiberfrax® (6 lbs/ft 3 ) in succession. Structural rigidity of the furnace was provided by a 3/16" steel plate enclosure. An exhaust hole having a 4"-diameter opening was located on the top face of the furnace.
Two laboratory, modular torches were used. The torches were rated at 50 kw of power with water-cooled cathode and anodes. The cathode was made of tungsten and had a sharp pointed tip. The anode consited of five individual segments made of copper. These anode segments had fine channels for water cooling. O-rings near the periphery helped to hermetically seal the segments. Critical adjustment of the cathode to the starting anode segment was necessary to keep a stable plasma flow. This accurate adjustment of the cathode-anode was provided by three micrometers in the cathode housing. During normal operation, the first segment was used as a starter and was electrically isolated from the other segments, whereas the other four segments were electrically shorted by placing brass shims between the segments.
Each plasma torch was attached at a torch mount assembly which could be detached from the main furnace structural body. Special insulation was provided in the torch mount assembly to safely accommodate the high temperature of the plasma torch. Castable fused aluminum oxide bubble refractory was used for the inner lining of the torch mount assembly. As a safety measure, a provision was also made to water cool the shell of the torch mount assembly. Water cooling, however, was found to be unnecessary for the operation of the plasma torches at 3500° C. or less.
Two nitrogen inlets were provided to each plasma torch; the first inlet acting as the primary plasma source and the second inlet used to dilute the primary stream to obtain the desired temperature of nitrogen. During normal operation, the primary nitrogen stream was supplied at 50-100 psi and the secondary nitrogen stream was supplied at 10 psi. When both torches were operating at peak power, the total nitrogen requirement was around 6 SCFM for the primary stream and around 20 SCFM for the secondary stream. Higher flow rates of around 40-50 SCFM were used during cooling.
The injection of secondary nitrogen for controlling the temperature of the inlet plasma nitrogen gas was carried out in a water-cooled cylindrical chamber, attached in front of the primary anode segments. The cold nitrogen was introduced in a tangential fashion at four points along the circumference of the cylindrical chamber.
A water supply of 7-10 gpm was used for cooling the electrodes of the plasma torch. Because of the presence of a large pressure drop within the plasma torch cooling system, it was necessary to boost the supply pressure sufficiently. A booster pump was installed to take care of this problem and had a capacity of delivering 15 gpm of water at 150 psi. A filtering unit with a 100 micron filter was installed to filter the cooling water.
A provision was made for an on-line supply of nitrogen gas from a liquid nitrogen tank. The nitrogen gas used in the plasma furnace was not recycled for simplicity of pilot operation.
The power supply to the torches was provided by four Miller welding units; two for each plasma torch. The two units were connected in parallel; each unit was rated at 40 kw of power (80 V at 500 A). The high impedance of this power supply helped in stabilizing the single phase plasma arc.
STACKING ARRANGEMENT EXAMPLES 1-10
Experiments were conducted to determine the heat transfer characterization. Heat was transferred from hot inlet gas to cold bricks in a counter current heat exchanger arrangement. The load consisted of 432 pounds of fired Refrax-20® bricks. Temperatures were measured at inlet and outlet ends to obtain heat tranfer rates by a calculation of logarithmic mean temperature difference. The time interval used in the calculation was 1 hour. Variables investigated were number of plasma torches (1-2), inlet gas temperature (2000° C., 3000° and 3500°), inlet gas volume (58-148 lbs/hr), and dense and open stacking patterns. Results are shown in Table 1. Table 1 lists the number of plasma torches, gas inlet temperature, packing arrangement, gas flow rate, and average heat transfer coefficient.
TABLE 1______________________________________SUMMARY OF MEASURED OVERALL HEATTRANSFER COEFFICIENTS InletNumber Gas Flow Heat Transferof Temp. Rate CoefficientEx. Torches (°C.) Packing (SCFM) (Btu/hr. °F.)______________________________________1 2 2000 Dense-Closed 14.6 2.772 2 3000 Dense-Closed 12.4 3.083 2 3500 Dense-Closed 12.0 2.934 2 2000 Dense-Closed 24.0 4.685 2 2000 Dense-Closed 30.2 5.786 1 2000 Dense-Closed 14.5 2.177 2 2000 Dense-Open 23.6 5.158 2 3000 Dense-Open 14.1 3.719 2 2000 Dense-Open 31.5 6.1810 2 2000 Light-Open 28.3 5.17______________________________________
(1) Overall heat transfer coefficient depended on the gas flow rate and packing arrangement.
(2) For a given stacking arrangement higher gas flow results in higher overall heat transfer coefficient.
(3) For a given flow rate and density of stacking arrangement open setting results in improved heat transfer rates.
(4) For a given flow rate and brick arrangement, two torches are more efficient than a single torch.
EXAMPLES 11-19
Experiments to determine the energy conversion efficiency of the plasma torch were conducted with radial and tangential injection of the secondary gas. Energy loss to cooling water was measured by measuring the flow as well as the inlet and outlet temperatures. Table 2 summarizes the power, primary and secondary gas flow rates and the efficiencies obtained for the case of tangential injection.
TABLE 2______________________________________OVERALL EFFICIENCY MEASUREMENT OFPLASMA TORCH Primary Secondary Power Gas Gas OverallExample (kw) (SCFM) (SCFM) Efficiency (%)______________________________________11 20 2.00 6.69 6312 35 2.00 13.72 6213 45 2.00 18.20 5914 20 3.00 1.79 5315 35 3.00 6.96 6516 45 3.00 9.62 6517 20 3.85 0.00 4618 25 2.60 3.20 5319 45 3.55 5.20 59______________________________________
(1) The overall maximum efficiency improved from 50.1 to 65.1 when switching from a radial to tangential injection.
(2) For a given primary gas flow, increase in secondary flow increases the overall efficiency up to 65%.
(3) To obtain efficiencies greater than 60% it is necessary to have a minimum of 5 SCFM of secondary gas.
EXAMPLES 20-29
Fired Refrax-20® bricks were randomly selected from each pilot plant test for physical (density and porosity), mechanical (cold modulus of rupture) and alkali resistance tests. A minimum of two bricks from each test was selected for this product evaluation. The density and porosity of the product was measured from test bars cut from the bricks. Modulus of rupture measurements were made on test bars using a 3-point bend test. Test bars were cut from the surface and interior portions of the brick, and were immersed in K 2 CO 3 /coke mixture at 927° C. for 6 hours to determine the alkali resistance.
TABLE 3__________________________________________________________________________SUMMARY OF PRODUCT EVALUATIONHeating Holding Holding AlkaliRate Temp Time Density Porosity MOR ResistanceExample(°C./hr) (°C.) (Hr.) g/cm.sup.3 % psi % change in wt.__________________________________________________________________________20 250 1500 3.0 2.61 17.44 4197 4.7521 250 1500 4.0 2.63 16.80 4623 3.9622 350 1400 3.0 2.61 17.28 5358 2.9123 350 1500 2.5 2.61 14.10 5058 4.9724 350 1550 1.5 2.61 16.10 4177 3.9525 350 1550 2.5 2.54 18.30 4143 3.4326 350 1550 1.5 2.61 15.90 4013 5.0527 250 1500 3.5 2.57 19.10 3708 2.8928 250 1500 3.5 2.61 17.50 4408 2.4529 350 1500 3.5 2.59 18.20 4300 2.13__________________________________________________________________________
The average density ranged from 2.54 to 2.63 g/cm 3 . It was found that the fired density was more dependent on green brick preparation (mix composition, as well as press conditions) than any other factors.
Average porosity values ranged from 14.1 to 19.1%. The scatter in the porosity data also indicated that porosity is more dependent on green brick preparation.
The average modulus of rupture obtained from the individual firing tests ranged from 3708 psi to 5058 psi. In general, the product from the plasma furnace had a lower cold modulus of rupture compared to tunnel or periodic kiln products.
It was found that there was no noticeable difference in corrosion behavior (alkali resistance) between the inside and outside of the bricks. Typically, the outer portion of a tunnel or periodic kiln brick is less resistant to alkali corrosion than the interior portion, thus plasma products performed better.
Although the invention has been described with reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. | A process for sintering or reaction sintering ceramic or refractory materials with hot plasma gases. The hot plasma gases are produced by injecting a combined primary plasma arc with a secondary gas stream directly into a reaction furnace. The secondary gas stream is tangentially injected into the primary plasma arc gas stream to mix the gases for the required sintering temperature at the highest energy efficiency. The plasma torches are positioned in the furnace ports so that the plasma gas flow is perpendicular to the furnace process gas flow. This process is inexpensive and efficient and results in a superior quality sintered product. It may be adapted to continuous or periodic kilns to achieve a high furnace productivity. | 2 |
FIELD OF THE INVENTION
[0001] The invention relates to a cushion of paper, and to a method and an apparatus for producing it.
BACKGROUND OF THE INVENTION
[0002] In packing various items, many kinds of cushions for filling voids are known, which are produced from paper web by crumpling. They are based on folding or rolling the edges of a paper web inwardly and then crumpling the folded or rolled paper web. From this continuously created web, individual cushion portions are then cut off to a desired length.
[0003] The object of the present invention is to create a paper cushion which has improved cushioning properties and is less expensive. Improved cushioning properties means that the product has higher resiliency and/or elasticity, or in other words provides better cushioning of items packed, in proportion to the quantity of paper used. A cushioning product is less expensive if less paper is required to fill a given volume, for example on the basis of the way in which the cushioning product is shaped.
SUMMARY OF THE INVENTION
[0004] One such product is characterized according to the invention in that the cushion is a crumpled paper tube. A paper tube, in the opened-out state, is upset and thereby crumpled. In comparison with previous products, more air is “trapped” inside this crumpled tube. The circular cross-section disposition of the paper leads to improved properties in cushioning and padding packed items.
[0005] These properties are improved still further by preferably providing that the paper tube is crumpled in the longitudinal direction and in the radial direction.
[0006] The cushioning properties are furthermore improved if the paper tube is provided in the longitudinal direction with a strip of paper or adhesive. This is expediently effected by providing that this strip and/or this adhesive is formed when a paper tube is produced from a paper web by folding or rolling in the edges and joining them together.
[0007] It is especially advantageous to use kraft paper, which is already intrinsically especially stable.
[0008] For producing such a cushion, it is expedient beforehand to “configure” a paper tube, that is, to prepare it, specifically by providing that one or more paper webs are joined together along their edges, for instance by directly adhesively bonding overlapping regions or by gluing strips on. These paper tube webs are then processed further to form the cushions or cushion portions in the apparatuses suitable for that purpose.
[0009] A paper tube web prepared and put together in this way can as a result be made smaller, or in other words narrower, by providing that along the two outer sides of the paper tube, in the flatly put-together state, indented folds are provided. Thus in a small space, more paper can be furnished and transported to the places where the paper tube web is processed further.
[0010] The paper tube web is preferably provided with intended tearing points at prepared, standardized intervals. These are points which tear when tension is exerted, as a consequence of the weakening of the material brought about by them. In other words, if tension is exerted on the paper tube web, it tears at the points where it is “supposed to” tear as intended. These points are preferably formed by a perforation and/or by certain notches or recesses.
[0011] The method for producing the cushion and the apparatus suitable for it are embodied such that the paper tube is slipped onto a core, which distributed over its circumference has rollers (inner rollers) that cooperate with rollers disposed outside the core (outer rollers), at least some of which are driven, and that thus draw in the paper tube, pass it between them, and crumple it. This is preferably accomplished by providing that two groups of rollers, spaced apart from one another in the longitudinal direction, are provided, which are driven at different circumferential speeds, so that between the two groups of rollers, crumpling by way of creasing of the paper material comprising the paper tube web occurs, and this creasing is crumpled further upon the passage through the second group of rollers.
[0012] This can be improved still further by providing that within the second-named group of rollers, further rollers are provided, which are disposed on a smaller boundary circle, so that the already-crumpled paper tube is also pushed together in the radial direction and crumpled anew on passing through the last-named rollers.
[0013] An apparatus for producing a cushion of paper comprises the provision of feeder means for the paper tube web that slip it onto a core and the provision of crumpling means, which crumple the paper tube web that has been opened out by being slipped onto the core. The feeder means are formed by rollers disposed in a first plane transverse to the feeding direction, which are provided both on the core (“inner rollers”) and outside the core (“outer rollers”) in the apparatus; all of these rollers initially continuously open out the paper tube once it has been inserted and then slip it onto the core. In further planes extending perpendicular to the transport direction of the paper tube web, further groups of rollers can be provided. They then, as already described, accomplish the crumpling in that first a circumferential creasing occurs by virtue of longitudinal compression, and then a radial compacting occurs by virtue of radial compression ensues.
[0014] Exemplary embodiments of the invention and advantageous refinements of them will be described below.
BRIEF DESCRIPTION OF THE DRAWINGS OF THE INVENTION
[0015] [0015]FIG. 1, an exemplary embodiment of a cushion;
[0016] [0016]FIG. 2, an exemplary embodiment of a paper tube from which by crumpling a cushion is created;
[0017] FIGS. 3 ( a ) through ( f ), various schematic illustrations of cross sections of a paper tube;
[0018] [0018]FIG. 4, the schematic illustration of a paper web processing unit for producing a cushion;
[0019] [0019]FIG. 4 a , the location of the axes of the rollers 16 , 20 , 21 relative to one another;
[0020] [0020]FIG. 5, a plan view on a paper tube web;
[0021] [0021]FIG. 6, a schematic illustration of a stand with a paper processing unit, as an apparatus for producing cushions;
[0022] [0022]FIG. 7, in perspective, a further exemplary embodiment of an apparatus for producing a cushion from a paper tube web;
[0023] [0023]FIG. 8, part of the apparatus of FIG. 7;
[0024] [0024]FIG. 8 a , a schematic illustration of the drive of the rollers in FIG. 7;
[0025] [0025]FIG. 9, a cross section taken along the arrows IX-IX in FIG. 7;
[0026] [0026]FIG. 10, a side view of the apparatus of FIG. 7;
[0027] [0027]FIG. 11, a plan view of the apparatus of FIG. 7;
[0028] [0028]FIG. 12, a cross section taken along ling 12 - 12 through the apparatus of FIG. 7;
[0029] [0029]FIG. 13, a perspective view of the core;
[0030] [0030]FIG. 14, a side of the core of FIG. 13;
[0031] [0031]FIG. 15, a cross section taken along line 15 - 15 through the core of FIG. 13;
[0032] [0032]FIG. 16, a second exemplary embodiment (modular construction);
[0033] [0033]FIG. 17, the exemplary embodiment of FIG. 16, with half of the frame and the core removed;
[0034] [0034]FIG. 18, the exemplary embodiment of FIG. 16, with the core inserted and the entire frame removed;
[0035] [0035]FIG. 19, a section through the exemplary embodiment of FIG. 16;
[0036] [0036]FIG. 20, a section taken in the direction of the arrows XX-XX in FIG. 19;
[0037] [0037]FIG. 21, a section taken in the direction of the arrows XXI-XXI in FIG. 19;
[0038] [0038]FIG. 22, a section taken in the direction of the arrows XXII-XXII in FIG. 19;
[0039] [0039]FIG. 23, a schematic drive diagram for the outer rollers in the exemplary embodiment of FIGS. 16 - 22 ;
[0040] [0040]FIG. 24, a brake;
[0041] [0041]FIG. 25, a slip coupling;
[0042] [0042]FIG. 26, a side view of the apparatus of FIG. 16.
DETAILED DESCRIPTION OF THE INVENTION
[0043] [0043]FIG. 1 shows a crumpled cushion, or a crumpled cushion portion 1 , having the length (in the crumpled state) a=approximately 28 cm, the inside diameter b=approximately 7 cm, and the outer diameter c=approximately 14 cm. It is understood that these figures are intended solely for purposes of illustration and are not to be understood as limiting. The cushion portion 1 is created by crumpling a prefabricated (configured) paper tube 2 , specifically in the form of upsetting in the longitudinal direction (axial direction) with ensuing compression. One such paper tube 2 is shown in perspective in slightly opened form in FIG. 2, in terms of the cross section of FIG. 3( a ). It involves a paper web 6 , which is folded as shown, that is, with two lateral indented folds 2 ′. The folded paper web has a portion 3 , at which the two edges 4 ′, 4 ″ overlap and are glued to one another by means of an adhesive layer 7 . Other possible cross sections of the paper tube 2 are shown in FIGS. 3 ( b ), (c), (d), and (e), and in FIG. 3( c ), (d), (e), strips 5 are shown with which the edges of the folded paper web 6 , or of two parallel paper webs 6 ′, 6 ″ are joined or glued together. In this prepared form, the term used is also a configured paper web, or a paper tube web 8 . FIG. 3( f ) illustrates another possible cross section of paper tube 2 wherein two parallel paper webs 6 ′, 6 ″ are joined or glued together via adhesive layers 7 , 7 between their confronting lateral edges.
[0044] The paper is preferably so-called “kraft paper”, that is, very firm, brown packing paper made of unbleached sulfate cellulose, usually using very long fibers, which is therefore especially tear-resistant. It is understood that this statement should again be understood only as an example. The webs are glued together, as already mentioned. The adhesive layers 7 that are striplike in the longitudinal direction of the cushion portion form, optionally together with the strip 5 , an additional reinforcement of the cushion, which enhances the cushioning properties.
[0045] [0045]FIG. 4 shows one basic embodiment of a paper processing unit 35 for creating a cushion 1 . A roll 11 is seated on a shaft 10 . The roll is formed by a configured, wound-up paper tube web 8 . This tube is drawn onto a core 15 by two pairs of driven rollers 16 and kept on hand there. One pair of rollers 16 can be seen; a further pair is located perpendicularly before and behind the plane of FIG. 4, in the same vertical plane. The rollers 16 are followed by rollers 17 , which are driven at a somewhat lower speed, so that between the two creasing 8 ′ ensues from upsetting, and upon passage through the paper tube web 8 between the rollers 17 and the core, this creasing undergoes crumpling. Two further rollers 17 are disposed in the same vertical plane, in FIG. 4 in front of and behind the core 15 , with their axes perpendicular to those of the rollers 17 shown. Pairs of rollers 20 , 21 , 22 , 23 , 24 that freely travel jointly are disposed on the core 15 and serve to provide for low-friction travel along the paper tube on the outside of the core. As shown in FIG. 4 a , the rollers 16 plunge by an amount h (plunging depth) between the rollers 20 , 21 , so that they secure the core 15 , in a defined position, against axial displacement.
[0046] One possibility for cutting off individual cushion portions from the continuously manufactured band is seen in FIG. 5. Once again, a paper tube web 8 is shown in plan view that has perforation lines 12 , or tearing points or lines of separation, at intervals of 80 cm, for instance. Along these lines, for instance at the spacing of half the width of the paper tube web, rhomboid cutouts 13 are provided. If the rollers 16 are now stopped at predetermined time intervals, which correspond to the processing of a particular longitudinal portion, and the rollers 17 are allowed to continue to rotate, then along the perforated line that is then located between the rollers 16 and 17 , one cushion portion 1 is torn off. The tearing off can also be done by other means in the transport direction T, before or after the apparatus shown. Separating the cushion portions can naturally also be done by a cutting device or other separating devices as well.
[0047] One simple design of a stand with a paper processing unit 35 for producing such a cushion portion is shown in FIG. 6.
[0048] The stand for the various components comprises a bottom plate and scaffold 31 , which has rolls 32 and 33 onto which configured paper tube webs 8 are wound. The upper roll 32 is the one from which a paper tube web 8 is just now being drawn off and processed. Roll 33 is a reserve roll. On the upper end of the scaffold 31 , by means of rail 37 , slot 36 and locking screw 39 , the processing unit 35 is disposed so as to be adjustable in height. The equipment can move from place to place by means of rollers 38 . The mounting of the two rolls 32 and 33 is done without shafts on further rolls (not shown.
[0049] FIGS. 7 - 12 show one exemplary embodiment of an apparatus for producing a cushion portion 1 in more detail.
[0050] In FIG. 7, a stand 40 can be seen, on the right-hand side of which two rollers 41 and 42 are provided, on which a roll 11 of a paper tube web 8 is disposed without a shaft.
[0051] As best seen from FIG. 8, outside the core 15 and therefore hereinafter also known as “outer rollers”, four upper rolls 43 , 44 , 45 , 46 and pairs of associated lower rollers 43 ′, 44 ′, 45 ′, 46 ′ can be seen. Transversely to this, but with axes in the same vertical plane and also facing one another in pairs, further pairs of rollers 61 , 61 ′, 62 , 62 ′, 63 , 63 ′, 64 , 64 ′ are provided (see also FIG. 11). These pairs of rollers cooperate with rollers that rotate freely on the core 15 , namely the pair of rollers 51 , 51 ′, the pair 52 , 52 ′, the two pairs of rollers 53 , 53 ′ and 54 , 54 ′, and the pair 55 , 55 ′. Among the “inner rollers” there are also further pairs, which are disposed with their axes perpendicular to the axes of the aforementioned rollers, but in the same vertical plane (in this exemplary embodiment), that is, the pairs of rollers 71 , 71 ′, 72 , 72 ′, 73 , 73 ′, 74 , 74 ′, 75 , 75 ′ (see also FIGS. 12 and 14).
[0052] The cooperation of only one of the outer pairs of rollers, namely of the outer pairs of rollers 45 , 45 ′ and 63 , 63 ′ with each of the two pairs of rollers 53 , 53 ′ and 54 , 54 ′ spaced apart from one another on the core 15 , secures the core 15 against an axial displacement, despite its being freely supported; in this respect, see also the explanation above for FIG. 4 a . Since the outer rollers are driven and are in engagement with the inner rollers, the paper tube web 8 is thus drawn through between the outer and inner rollers and, as a consequence of different drive speeds of the outer rollers, is folded between them and then crumpled.
[0053] The drawing in of the paper tube web is effected by the two pairs of rollers 61 , 61 ′ and 43 , 43 ′ facing one another, while the emergence of the upset roll is effected by the pairs of rollers 64 , 64 ′ and 46 , 46 ′.
[0054] For driving the “outer roller”, a central electrical drive motor 80 is provided, to which a gear 81 for stepping down the rotary speed is flanged. The power takeoff shaft 82 is connected to the gear 83 , which in turn first drives the shaft 84 , deflected by 90°, and second drives the shaft 85 , which in turn, deflected by 90° in the gear 83 ′, drives the shaft 99 . The gear wheels 90 and 91 are seated on the shaft 84 . The gear wheel 90 drives the gear wheel 92 on the shaft 93 via a chain 220 and gear wheel 91 and drives the gear wheel 94 on the shaft 95 via chain 221 . The shaft 95 extends from the top inward into the gear 96 , which deflected by 90° drives the shaft 97 , which extends into the gear 98 , which deflected by 90° drives the shaft 86 and thus the roller 63 ′. Also seated on the shaft 95 is a gear wheel 100 , which via a chain 222 drives the gear wheel 101 and thus the shaft 102 , on which the roller 64 is seated. The shaft 99 likewise drives a gear wheel 103 (see FIG. 8 a ), which via a chain 223 drives the gear wheel 107 and thus the shaft 108 and thus also the roller 61 ′. The rollers disposed perpendicularly move freely in part. The roller 44 on shaft 109 ′ is coupled to the shaft 84 via a bevel gear connection 109 . It is understood that pulleys may be used instead of the chains. In this way, it is possible to make do with only one motor.
[0055] By means of different gear ratios from the shaft 82 to the shaft 85 on the one hand (gear 83 ) and shaft 84 to shaft 95 on the other (gear wheels 91 , 94 ), it is attained that the rollers 61 , 61 ′, 62 , 62 ′ located in the vicinity of the drawing-in region, that is, to the right in FIG. 8, travel somewhat faster than the rollers 63 , 63 ′, 64 , 64 ′ downstream of them in the transport direction, so that the aforementioned creasing 8 ′ can occur.
[0056] Groups of rollers are described herein. In the exemplary embodiment of FIGS. 1 - 5 , the first group is formed by those rollers whose axes are located (see FIG. 12) in the vertical planes A and B (in terms of the exemplary embodiment of FIGS. 8 - 12 , that is, perpendicular to the transport direction T of the paper tube). The second group of rollers is formed by those rollers that are located in the vertical planes C. The third group forms the rollers in the plane D.
On the apparatus On the core 15: outside the core 15: Group Vertical Plane “Inner Rollers” “Outer Rollers” First A 51, 75, 51′, 75′ 43, 61, 43′, 61′ B 52, 74, 52′, 74′ 44, 62, 44′, 62′ Second C 53/54, 72/73, 45, 63, 45′, 63′ 53′/54′, 72′/73′ Third D 55, 71, 55′, 71′ 46, 64, 46′, 64′
[0057] Each two inner rollers (such as 53 / 54 ) that are associated with an outer roller (such as 51 ) and are associated with one another by the symbol “/” have a certain spacing from the plane C shown in FIG. 12, but this spacing is not critical in the present situation. They cooperate with a third roller and serve to fix the core 15 in the axial direction (see the explanation above for FIG. 4 a ).
[0058] The rollers of the first group travel at a “first” circumferential speed, and the rollers of the second group travel at a “second” circumferential speed that is less than the first circumferential speed. The result is a crease (see 8 ′ in FIG. 4), which upon passage through the second group is also crumpled.
[0059] Upon passage through the rollers of the third group in plane D, crumpling occurs again, specifically as a consequence of the lesser diameter of the core 15 at this point, including in the radial direction. This radial decrease in diameter takes place at the transition of the paper tube from the portion 200 to the portion 201 (see FIG. 13). The term “diameter” is not meant to be understood strictly here but instead pertains to the approximate outline around the plates 130 , 131 , 150 , 151 at the applicable point. Accordingly, compressive crumpling of the paper tube takes place in the axial direction and in the radial direction, the latter taking place in/after the diameter reduction of the core and thus of the paper tube.
[0060] In FIGS. 13 - 15 , the construction of the core 15 in detail.
[0061] As seen in FIG. 13 and FIG. 14, the core 15 is constructed of two parts, namely a front part 120 in terms of the transport direction and a rear part 121 in terms of the transport direction. The dividing line is marked 120 ′. The two parts are joined together, in this specific case in that the front part has a connecting element 125 , which is connected on the one hand to the front part 120 by means of the screw 126 and on the other to the rear part 121 by means of the screw 127 .
[0062] If the two parts are viewed together in the assembled state (see FIG. 14), it can be seen that the core 15 substantially comprises an upper plate 130 and a lower plate 131 , which are joined to one another, via spacers 140 , 141 , 142 that are disposed between them, by means of screws 145 . The rollers 71 ′- 75 ′ (and behind them and therefore not visible, the rollers 71 - 75 ) are then disposed between the plates.
[0063] Both on the upper plate 130 and on the lower plate 131 , two further plates 150 , 151 each are disposed continuously (but in two parts, corresponding to the front part 120 and the rear part 121 ), these further plates being parallel and perpendicular to the plates 130 , 131 ; these further plates serve to support the rollers 51 - 54 , that is, on the underside 51 ′- 55 ′.
[0064] [0064]FIG. 16 shows a further exemplary embodiment of modular construction, in which all the rollers are disposed inside a boxlike frame 230 , which comprises two frame portions 231 and 232 , bent at right angles, which are screwed to another by means of the angle brackets 233 . The shaft 234 protrudes from the frame 230 at the bottom. It corresponds to the shaft 84 in FIG. 8 and FIG. 8 a and is connected to a drive motor, not shown in FIG. 16. Within the module, the core is also fixed in the axial direction between the rollers. A guide baffle 236 that is adjustable by means of screws is disposed on the frame, and the paper tube web 8 can be delivered via its guide face 237 . The paper tube web is drawn across the mushroom-shaped inlet head 238 and opened out in the process and pulled through between the rollers.
[0065] As seen from FIGS. 20 and 23, the shaft 234 carries the outer roller 241 and, via the two bevel gears 301 and 302 , drives the shaft 303 and thus also the roller 251 . The shaft 303 , via the bevel gears 304 , 305 , then drives the shaft 306 and thus also the roller 241 ′. The shaft 234 moreover, via the bevel gear 307 and the bevel gear 308 , drives the shaft 309 , on which the roller 251 is seated. The rollers 241 , 241 ′, 251 , 251 ′ cooperate in such a manner with rollers 261 , 261 ′, 262 , 262 ′, 271 , 271 ′, 272 , 272 ′, disposed freely rotatably on the internal tube 310 , which is part of the core 235 , that when the shaft 234 is driven, a paper tube web 8 is pulled through, between the outer rollers and the inner rollers. The rollers 261 , 261 ′, 271 , 271 ′ are seated perpendicular to the plane of FIG. 20 just before the rollers 262 , 262 ′, 271 , 271 ′ (see FIG. 19 and FIG. 26). The two “inner rollers” disposed in pairs before and behind the plane in FIG. 20 cooperate with the “outer rollers” in order to axially fix the core.
[0066] Seated on the shaft 303 (FIG. 20) on one side (to the right) of the roller 251 is the gear wheel 311 , and on the other is the gear wheel 312 .
[0067] The gear wheel 311 , via a chain or pulley (not shown), drives the gear wheel 313 on the shaft 314 (see FIG. 21). The shaft 314 carries the bevel gears 315 and 316 , which via the bevel gears 317 and 318 drive the shafts 319 and 320 . In this way, the rollers 240 , 240 ′, 250 , 250 ′ seated on these shafts are driven, and in turn cooperate with the rollers 260 , 260 ′, 270 , 270 ′ in such a way that between a paper tube web 8 can be drawn in and pulled through.
[0068] The gear wheel 312 (FIG. 20), via a chain or a pulley (not shown), drives the gear wheel 325 (see FIG. 22), on which the shaft 326 that carries the roller 252 is seated. Via the bevel gears 327 , 328 , 329 , 330 , the shaft 326 drives the shafts 331 and 331 ′ and thus the rollers 242 , 242 ′ seated on them. Seated on the lower end of the shaft 331 is a bevel gear 332 , which drives a bevel gear 333 . The latter drives the shaft 334 and thus the roller 252 ′.
[0069] In this exemplary embodiment, the rollers 242 , 242 ′, 252 , 252 ′ (“outer rollers”) are not assigned any corresponding rollers, cooperating with them, on the core or on the internal tube 310 . To bring about the crumpling of the tube passing between these rollers on the one hand and the internal tube 310 on the other and already crumpled and now radially compressed, and to improve this crumpling and at the same time to reinforce the feeding of the tube in the transport direction T, the rollers 242 , 242 ′, 252 , 252 ′ have pins 335 distributed at regular intervals along their circumference.
[0070] The shafts are each in bearings 359 that are provided in gibs 350 - 357 (see FIG. 17). The gibs are screwed to the frame portions 231 and 232 , for example by means of the screws 358 (see FIG. 16).
[0071] Thus a paper web tube 8 is drawn manually onto the core 235 in the transport direction T at the beginning of the procedure, placed between the rollers 250 , 250 ′, 240 , 240 ′ (outer rollers) and the rollers 260 , 260 ′, 270 , 270 ′ (inner rollers), and as soon as these rollers engage it, it is drawn by them continuously between them and pulled through between them, because of the fact that the outer rollers are driven as described. Next, they are pulled through between the rollers 251 , 251 ′, 241 , 241 ′ (outer rollers) and the rollers 261 , 261 ′, 262 , 262 ′, 271 , 271 ′, 272 , 272 ′ (inner rollers), but at a lower speed. Accordingly what occurs between these two groups of rollers is a creasing, which is not shown in these drawings, but can be seen in FIG. 4 (at 8 a ). The first group is formed by the outer rollers 240 , 240 ′, 250 , 250 ′ and the inner rollers 260 , 260 ′, 270 , 270 ′. The second group is formed by the outer rollers 241 , 241 ′, 251 , 251 ′ and the inner rollers 261 , 261 ′, 262 , 262 ′, 271 , 271 ′, 272 , 272 ′. To make it possible for the creasing to occur, however, the diameter of the paper web tube must be correspondingly greater than that of the core.
[0072] The different speeds of the first and second groups of rollers is due to the fact that the gear ratio of the gear wheel 311 (FIG. 20) to the gear wheel 313 is designed accordingly.
[0073] A further crumpling then takes place upon the reduction in the radial spacing (relative to the center line of the internal tube 310 ) of the paper web tube as it is transported from this second group of rollers to the third group of rollers, formed by the rollers 242 , 242 ′, 252 , 252 ′. These are “outer rollers”. This exemplary embodiment does not have any “inner rollers” corresponding to outer rollers 242 , 242 ′, 252 , 252 ′. Nevertheless, further crumpling occurs. The speed of revolution of this third group of rollers is determined by the gear ratio of gear wheel 312 (FIG. 20) to gear wheel 325 (FIG. 22).
[0074] It should furthermore be noted that the inner rollers are supported on the internal tube 310 because suitably U-shaped bearing brackets 360 are screwed onto the internal tube (FIGS. 20, 21).
[0075] To brake outer rollers of the first group of rollers, or —more precisely—the driven outer rollers 240 , 240 ′, 250 , 250 ′ (see FIG. 21), in order to bring about tearing off of the paper web tube at the “intended tearing points” 9 / 9 ′ (see FIG. 5), the following provisions are made: A brake wheel 361 , fixed in a groove 363 by a tongue 362 , is disposed on the shaft 320 (FIG. 21). The brake wheel 361 can, as seen from FIG. 24, be brought to a standstill by a brake belt 365 , when the electric motor 366 is excited. Then the armature 367 , on which the retaining rod 368 is secured with the brake belt 365 , is drawn inward by approximately 2 mm in the direction of the arrow. This tenses the brake belt 365 and stops the motion of the shaft 320 . As a consequence of the geared connection via bevel gears and shafts, this stop then causes a corresponding stop of the outer rollers 240 , 240 ′, 250 , 250 ′ shown in FIG. 21.
[0076] So that despite the aforementioned stop, the driven rollers 241 , 241 ′, 251 , 251 ′ (FIG. 20) can continue to rotate, the gear wheel 313 (FIG. 21), which is driven by shaft 303 via the gear wheel 311 and pulleys, is supported on the shaft 314 by means of a slip coupling 370 , which is shown in further detail in FIG. 25. This slip coupling makes it possible for the second group of rollers to continue rotating while the first group is stopped. The paper web tube then tears.
[0077] The slip coupling functions as follows: The roller 250 is supported on the shaft 314 in the groove 369 by means of the tongue 369 ′. The gear wheel 313 rests laterally on the roller 250 but is not solidly connected to it. Inside the gear wheel 313 , there is a further gear wheel 371 , whose left-hand shoulder 371 ′ is seated on an associated shoulder face 313 ′ of the gear wheel 313 . The gear wheel 371 is coupled in the direction of rotation to the shaft 314 by the tongue 372 also engaging the groove 369 and is pressed from right to left (in FIG. 25) into contact against the gear wheel 313 . An adjusting screw 374 is screwed into a recess 373 , provided with a female thread 373 ′, in the gear wheel 371 . The adjusting screw, with its outer shoulder 374 ′, presses against the cup spring 375 , which in turn, with its outer leg 375 ′ bent over inward, exerts pressure on the gear wheel 313 . The adjusting screw 373 is fixed in the axial direction because it is screwed onto a male thread of the tubule 376 , which is disposed fixedly on the shaft 374 by means of a pin 377 . In other words, the farther the adjusting screw 374 is screwed inward (to the left in FIG. 25), the harder the cup spring 375 with its leg 375 presses on the end face of the gear wheel 313 . As a result, the shaft 314 is coupled frictionally to the gear wheel 313 . However, the coupling is dimensioned such that whenever—as described—the shaft 314 is brought to a stop, the gear wheel 313 , overcoming this friction, can rotate further. The adjusting screw 374 can be adjusted from outside by the engagement of a suitable pin with one of the transverse bores 378 .
[0078] The braking device, comprising electromagnet 366 and brake belt 365 , is connected to a support plate 380 , which is screwed to the frame portion 232 (see FIG. 26). | The invention relates to a crumpled paper tube for use as a cushion in packing items, and to a method and apparatus for producing the same. | 1 |
RELATED APPLICATIONS
[0001] This application is claiming the benefit, under 35 U.S.C. §119(e), of the provisional application filed on May 15, 2012, under 35 U.S.C. §111(b), which was granted Ser. No. 61 / 647 , 093 , and is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to night grinding appliances. More particularly, the invention relates to custom-formable night-grinding dental appliances that are thin and have a multiplicity of strategically placed perforations. The perforations facilitate breathing and the flow of saliva while maximizing the protection of teeth with regard to bruxism or other mechanisms leading to biomechanical wear of dental surfaces.
BACKGROUND OF THE INVENTION
[0003] Many dental patients suffer from temporomandibular joint disorder (TMD), a condition involving the improper functioning of the jaw and the temporomandibular joint. One of the conditions leading to TMD is bruxism, the subconscious clenching and grinding of teeth that typically occurs during sleep, but that may also occur while the patient is awake. In some cases of bruxism, the forces from jaw movements lead to tooth enamel damage, and over time the exerted excessive pressure can cause damage to the TMJ's articulating surfaces and lead to abrasion of the teeth surfaces. One of the treatments for bruxism is to insert custom-formed dental appliances, also known as “night grinding appliances”, or “bruxism protective device” or “mouth guards” to prevent direct contact of the occlusal surfaces of the teeth.
[0004] Night grinding appliances or fitted mouth guards are typically prescribed by dentists and custom formed. Typically, the dentist first takes an impression of the patient's teeth, and a cast of the maxillary upper arch is fabricated. Then, a polymeric material, usually an acrylic material is molded over the cast while applying a vacuum. The resulting fitted mouth guard is then trimmed and polished. Alternatively, multiple layers of polymer are laminated together under pressure in an attempt to improve the physical properties of the protective layers. These custom-made fitted mouth guards tend to be very expensive, and require a visit to the dentist, and, in some cases, fabrication in a dental laboratory.
[0005] Mouth guards for other uses, such as sports, do not provide protection against shear forces created by bruxism. Sports guards are developed to accommodate single, quick, large forces that are acting substantially normal to the tooth outer surface. Sports guards have no mechanism to contend with constant, low level shear forces from the user's own teeth.
SUMMARY OF THE INVENTION
[0006] The invention is a generally U-shaped dental appliance made of polycaprolactone or other thermoplastic polymer with a low softening point. The appliance is substantially thinner than conventional dental trays and has strategically located perforations. The majority of the perforations are disposed primarily outside of an arc-shaped region associated with a user's bite line. The perforations facilitate breathing and unrestricted flow of saliva. The appliance can easily be heated to its softening point and custom-fitted by a dentist, other health professional, or even by the patient conforming exactly to the contours of the user's dentitions.
[0007] The fitted dental appliance provides superior protection against damage to the enamel of the teeth and abrasion of the teeth due to bruxism or other mechanisms leading to biomechanical wear of dental surfaces.
[0008] The appliance facilitates the custom-fitting process by allowing the user to suck air and saliva through the perforations, thus applying a negative pressure between the material and the teeth while the material is still soft and pliable. The result is within a short time a conformal fit around every tooth as the material hardens, thus enabling a user or health professional to create a final product that rivals the quality and fit of an appliance made by dental laboratories using dentist made impressions.
[0009] The appliance has a periphery including a plurality of lobes and cusps to enhance custom fitting by allowing the softened material to envelop the teeth without buckling.
[0010] After fitting to the patient's dentitions, the fitted appliance cools to ambient temperature and contracts slightly, thus conforming even better to the contours of the user's dentitions, and thereby preventing the appliance from getting dislodged or falling out during sleep.
[0011] The appliance covers only the teeth and not the gum line on the labial side and the palate on the lingual side, in order to not cause discomfort, irritation of the gums, gagging, or inhibited breathing and saliva flow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The features of the subject invention will be better understood in the context of the detailed description, in conjunction with the drawings.
[0013] FIG. 1 is a scanning electron micrograph of an unformed tray taken at 8,000× magnification, showing the interwoven strands of the polymer imparting high abrasion resistance.
[0014] FIG. 2 is a schematic illustration of an unformed tray with strategically placed perforations.
[0015] FIG. 3 is a schematic cross section of two adjacent perforations before (a) and during (b) application of grinding forces, illustrating how the shape of the perforations changes during application of grinding forces.
[0016] FIG. 4 shows a frontal view of the fitted appliance.
[0017] FIG. 5 shows a bottom view of the fitted appliance depicting a lower surface of the appliance that is in contact with the dental surfaces.
[0018] FIG. 6 shows another bottom view of the formed appliance.
[0019] FIG. 7 a depicts one embodiment of a formed appliance with circular perforations.
[0020] FIG. 7 b depicts another embodiment of a formed appliance with circular and teardrop perforations.
[0021] FIG. 7 c depicts another embodiment of a formed appliance with half moon and teardrop perforations.
[0022] FIG. 7 d depicts another embodiment of a formed appliance with half moon perforations.
[0023] FIG. 8 shows one embodiment of the formed appliance on the dentitions of a user.
DETAILED DESCRIPTION OF THE INVENTION
[0024] It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments.
[0025] Turning now to FIG. 4-6 , one embodiment of a mouth guard 10 is depicted. The mouth guard 10 has an inner upstanding wall 12 with an inner surface 14 and an outer surface 16 . The two surfaces 14 , 16 are generally parallel one another. The guard 10 also has an outer upstanding wall 18 with an inner surface 20 and an outer surface 22 . The two surfaces 20 , 22 are generally parallel one another. The inner upstanding wall 12 and the outer upstanding wall 18 are connected at their base portions with a U-shaped occlusal line portion 24 to form a U-shaped cross section. The walls 12 , 18 of the guard 10 and the occlusal line portion 24 are unitarily formed as one piece. The occlusal line portion 24 is the part of the device that covers the bite line—the surface of the protected dentition that comes in contact with the surface of the dentition on the other jaw when the individual bites down during grinding or clenching. The occlusal line portion 24 can also be appreciated from FIG. 8 .
[0026] Although the guard 10 may have an upper edge portion 26 of the outer upstanding wall 18 that is relatively straight, in the preferred embodiment a number of small lobes and cusps are located in the outer upstanding wall 18 . The lobes and cusps are used to enhance the custom fitting process of the guard 10 to the user's teeth by allowing the softened guard material to adapt to any shape of the user's dentitions during the fitting process. As shown in FIG. 4 , the upper edge portion 26 of the outer upstanding wall 18 is provided with at least one cusp. A first cusp 28 is provided between a right half 30 and a left half 32 on a centerline 34 at a forward portion 36 of the outer upstanding wall 18 . The guard 10 is symmetric about the centerline 34 .
[0027] Preferably, a second cusp 38 is provided on the upper edge portion 26 of the outer upstanding wall 18 as well. In the depicted embodiment, the second cusp 38 is provided at a rearward portion 40 of the outer upstanding wall 18 . The second cusp 38 is positioned so that it is located between the user's incisors and molars (see also FIG. 8 ). A lobe 42 formed between points 44 and 46 . Lobes 42 and cusps 28 , 38 are not depicted on the inner upstanding wall 12 but they may be used on this wall 12 as well.
[0028] A cusp 28 , 38 is defined as an indentation of the wall 18 of the mouth guard 10 , and a lobe 42 is defined as a protruding portion of the wall 18 of the guard 10 . Without such cusps 28 , 38 and lobes 42 , a guard 10 that has been softened to mold against a user's teeth tends to fold or buckle when the guard 10 is wrapped around teeth and gums during fitting. This is especially the case if the curvature and shape of the dentitions are uneven. If such folding occurs when the material hardens during the fitting process, the fitted mouth guard 10 may become uncomfortable to wear, irritating the inside of the lip, and compliance to wear it may decrease. Thanks to these cusps 28 , 38 and lobes 42 the final result is a conformally fitted mouth guard 10 that has an outer upstanding wall 18 and an inner upstanding wall 12 both without folds and irregularities and that is extremely comfortable. Another effect of such cusps 28 , 38 and lobes 42 is that shear forces to the fitted mouth guard 10 , as applied from the lower jaw during grinding, are dissipated away from the occlusal line portion 24 , and up towards these cusps 28 , 38 and lobes 42 , thereby decreasing the negative effect of grinding on the dental surfaces.
[0029] Multiphysics computer simulation analysis has shown that the cusps 28 , 38 , representing singular points on the curvature of the fitted mouth guard 10 , act as zones where stresses in the material are concentrated and energy is dissipated, adsorbing and dissipating forces from high impact areas, i.e. the occlusal line portion 24 . When shear forces are applied to the fitted mouth guard 10 during grinding or clenching of teeth, a deformation wave front travels though the walls 12 , 18 and crests at a cusp 28 and/or 38 . This directs the impact energy away from the dentition and concentrates it harmlessly in the cusp 28 and/or 38 .
[0030] As shown in FIGS. 3A , 4 - 6 , a plurality of openings 48 are located in the inner upstanding wall outer surface 16 . The openings 48 connect with a plurality of perforations 50 extending through to the inner upstanding wall 12 . The perforations 50 connect with a plurality of exits 52 in the inner upstanding wall inner surface 14 .
[0031] As also shown in FIGS. 4-6 , a plurality of openings 54 are located in the outer upstanding wall outer surface 22 . The openings 54 connect with a plurality of perforations 56 extending through the outer upstanding wall 18 . The perforations 56 connect with to a plurality of exits 58 in the outer upstanding wall inner surface 20 .
[0032] The strategically placed perforations 50 , 56 in the guard 10 distribute the forces from clenched teeth more evenly and prevent abrasion of the teeth. The perforations 50 , 56 increase the ability of the guard 10 to dissipate energy produced during grinding and clenching of teeth by redirecting the forces generated when teeth are clenched and dissipating the energy by temporarily distorting their shape.
[0033] As shown in FIGS. 3 a , and 4 - 6 , the openings 48 , 54 and exits 52 , 58 maybe circular in shape and the perforations 50 , 56 may be cylindrical. The openings 48 , 54 , exits 52 , 58 , and perforations 50 , 56 temporarily deform from circles into ovals in the region where a grinding and/or clenching force is applied, as schematically depicted in FIG. 3 b.
[0034] FIGS. 3 a and 3 b , depict two openings 48 , exits 52 and corresponding perforations 50 in the inner upstanding wall 12 . A shear force 60 , which is applied during grinding, travels along the outer surface 16 (in this example) as a wave. The wave encounters a first perforation 64 , which becomes temporarily deformed by the wave. The wave deforms the first perforation 64 , which has a circular cross-section, into a perforation with an oval cross-section, which expends some of the energy of the wave. The guard 10 in which the perforation 64 is located maintains a constant volume. Thus, a second perforation 66 , which is proximate the first perforation 64 , gets compressed to account for the deformation of the first perforation 64 . The combination of perforation 64 deformation and the compression of an adjacent perforation 66 acts to absorb the laterally moving shear force in the guard 10 . The amount of compression of an adjacent perforation 66 is a function of the amount of deformation caused by the first perforation 64 . It can be appreciated that the deformation and compression occurs across many perforations simultaneously in the guard 10 .
[0035] Based on the foregoing, it can be appreciated that a shear force generated at a rear portion 68 of the guard 10 can be dissipated before it reaches a forward portion 70 of the guard 10 thus causing no distortion in the forward portion 70 perforations.
[0036] The perforations 50 , 56 are placed in the walls 12 , 18 to maximize the tensile strength of the guard 10 without exposing any of the protected dental surfaces to the unprotected teeth on the opposite jaw. The location of the perforations 50 , 56 also optimizes saliva flow around the dentitions, which improves comfort.
[0037] The perforations 50 , 56 improve comfort, i.e. improve breathing and decrease drooling, i.e. the flow of saliva outside the mouth. Breathing is improved since the perforations 50 , 56 allow the guard 10 to be thinner and thus take up less space in the mouth. Drooling is decreased since saliva can be sucked straight through the perforations 50 , 56 in the guard 10 . Drooling is a common problem with conventional dental devices and a major reason for poor compliance to use them. The optimized saliva flow in the current invention that enables the user to suck saliva straight through the guard 10 , thus avoiding saliva accumulation around it, mimics the natural sucking and swallowing of saliva an individual does automatically during sleep.
[0038] The perforations 50 , 56 also improve the fitting procedure. The fitting procedure begins by taking the tray 72 depicted in FIG. 2 . The tray 72 is heated, such as by hot water, microwave energy, or the like. Upon application of heat, the tray 72 becomes malleable. The heated tray 72 is put into the user's mouth and against the occlusal line of one set of teeth, such as the top set of teeth.
[0039] The perforations 50 , 56 allow the user to suck saliva and air through the perforations 50 , 56 during the fitting process. This creates a slight vacuum between the softened guard 10 and the dentitions thus attracting the softened material to the dental surfaces and molding it perfectly around the contours of every tooth. The perforations 50 , 56 allow the user to suck the softened appliance down onto the dental surface without having to apply any external mechanical pressure. The result is a perfect fit around every individual tooth, no matter the shape or relative location of an individual tooth. Upon cooling, the material retains the shape obtained during the molding process. This overcomes a major problem with conventional fitted mouth guards, where the user has to press the fingers onto the lips from the outside to form the softened fitted mouth guard to the teeth, with generally poor results.
[0040] The perforations 50 , 56 can be manufactured in a variety of shapes, sizes, and directions through the unformed tray 72 , but are typically in the range of 1-2 mm in diameter and shaped as cylindrical, straight, horizontal channels penetrating the walls 12 , 18 of the formed guard 10 . The location, shape, and direction of these perforations 50 , 56 may vary depending on demands on saliva flow, since saliva flow is not uniform throughout the oral cavity. For instance, the saliva flow is higher close to the ducts of the Parotid and submandibular saliva glands, located in the buccal mucosa and in the floor of the mouth. The location of these salivary glands ducts correspond to the rear portion 68 of the fitted guard 10 (Parotid glands) and the inner wall in the midline (Submandibular glands), and the perforations 50 , 56 could be bigger in these locations to compensate for greater saliva flow.
[0041] Since perforations 50 , 56 have been proven to increase the ability of the material to dissipate energy produced during grinding and clenching of teeth by temporarily deforming the cylindrical shape of the perforations 50 , 56 , a wide variety of the number of perforations 50 , 56 and of their exact locations and directions in the material can be used. The present invention can be used on upper as well as lower teeth to improve protection.
[0042] The location, size and shape of the perforations 50 , 56 are arranged in special patterns that are optimized to dissipate the shear forces applied to the grinding guard by the teeth of the user suffering from bruxism. Enhanced absorption and dissipation of shear forces can be achieved by strategically placing perforations 50 , 56 having complex shapes such as tear drop shapes or half-moon shapes, as illustrated in FIG. 7 a - d. In some cases, nonsymmetrical perforations, whose shapes are not symmetrical to the laterally traveling shear force wave, are preferable for their ability to absorb and dissipate shear forces.
[0043] It is preferred that at least two perforations 50 , 56 are located adjacent one another and that the perforations 50 , 56 have different shapes. By way of example, a guard 10 might have a circular perforation directly adjacent a teardrop perforation. Preferably, adjacent means that the adjacent perforations are no more than 1-2 perforation diameters away from one another with no intervening structure. This close relationship of perforations is preferred because it allows them to be in force transmitting communication with one another. In one embodiment, the distance between perforations is less than approximately 3 mm and preferably between approximately 1-2 mm.
[0044] FIG. 7 a depicts one embodiment where two rows of perforations are provided. These perforations 56 are from the outer upstanding wall 18 . A first upper row 74 is above a second lower row 76 wherein the perforations 56 in the respective rows are laterally offset from one another and do not overlap. In this embodiment, the perforations 56 in both rows are circular/cylindrical.
[0045] FIG. 7 b depicts another embodiment where two rows of perforations are provided. A first upper row 74 is above a second lower row 76 wherein the perforations 56 in the respective rows are laterally offset from one another and do not overlap. The perforations in the first row 74 are circular/cylindrical 78 ; the perforations in the second row 76 are a teardrop shape 80 .
[0046] FIG. 7 c depicts another embodiment where two rows of perforations are provided. A first upper row 74 is above a second lower row 76 wherein the perforations 56 in the respective rows are laterally offset from one another and do not overlap. The perforations in the first row 74 are a combination of circular/cylindrical 78 and tear dropped shaped 80 ; the perforations in the second row 76 are a combination of half moon shape 82 and circular/cylindrical 78 .
[0047] FIG. 7 d depicts another embodiment where two rows of perforations are provided. A first upper row 74 is above a second lower row 76 wherein the perforations in the respective rows are laterally offset from one another and do not overlap. The perforations in the first row 74 are circular/cylindrical 78 ; the perforations in the second row 76 are a half moon shape 82 .
[0048] Based on the foregoing, it can be appreciated that guards 10 can be highly customized to individual bruxism issues of a user. The location, size and shape of perforations can be tailored to the specific type and severity of bruxism experienced by a user.
[0049] The shapes, sizes, and exact location of these perforations are determined by multiphysics computer simulations. These multiphysics computer simulations allow to determine the optimum pattern distribution and perforation shapes that allow the guard 10 to deform in such a way that the shear forces applied during grinding are directed into distortions of the perforation shapes in a lateral direction, thereby dissipating energy and protecting the underlying teeth. This permits the appliance to dissipate shear forces by deformation of selected perforations in grinding guard regions that experience shear forces, while maintaining the remaining perforations unaltered. This feature preserves the excellent fit of the grinding guard 10 even under severe bruxism conditions. It is important to note that this mechanism of energy dissipation is fundamentally different than the principles of operation of prior art mouth guards where cylindrical perforations were used to dissipate vertically applied compressive forces. Here, horizontal shear forces are redirected to change the shape of the perforations, a fundamentally different energy absorption mechanism made possible by the special shape of the perforations.
[0050] Dental appliances 10 according to this invention are made from a material that is considerably tougher than conventional stock boil and bite appliances, typically made of ethyl vinyl acetate (EVA). The increased toughness of the material improves its ability to absorb energy and its resistance to damage when stressed during clenching and grinding of teeth.
[0051] The material used in this invention is substantially less compressible than the materials used in conventional boil and bite appliances. Preferably, the material is substantially incompressible and substantially constant volume. By way of example, the material may be such as polycaprolactone or other thermoplastic polymers. According to a multiphysics computer simulation, the material in the current invention deforms only 1.4% under a static load of 2 MPa in comparison to 35% for EVA used in conventional appliances. The less a dental device compresses under impact the less it “caves in”. This means that the impact forces dissipate laterally over the device rather than being transferred through the material to the underlying teeth. Better dissipation of forces increases the protection of the dental surfaces. Since compression of the current invention is only 1/25 of conventional dental devices, the transferred forces to the teeth are just a fraction of those in conventional devices, and the degree of protection of the dental surfaces by the current invention is significantly better. Furthermore, less compression results in less permanent deformation of the material itself, which increases its durability. The decreased deformation maintains the excellent conformal fit of the appliance during clenching of teeth and prevents dislodging of the appliance from the dentitions.
[0052] Conventional, EVA based appliances need to be about 4 mm thick to provide adequate protection. Thanks to the superior properties of the material in the current invention, a thickness of on average 1.6 mm (range 1.0-2.5 mm) is sufficient to provide adequate protection of the dentitions against abrasion during grinding of teeth. The thinner a night grinding fitted mouth guard 10 is the more comfortable it is, which in turn is important for compliance to use the guard. Bulkier dental device tend to cause gagging. Furthermore, a thinner fitted mouth guard 10 is easier to fit around individual teeth, especially when perforations and the pliability of the current material allows custom fitting to any surface.
[0053] The unformed tray 72 may have a uniform thickness, however, when it is fitted the thickness of the appliance may vary. For example, the thickness of the fitted guard 10 may vary in different areas between 1.0 and 1.8 mm when the unformed tray thickness is approximately 1.6 mm. The varying thickness may occur in different areas of the unformed tray to provide increased comfort to the user. Furthermore, the unformed tray 72 may be deliberately made thicker in specific areas where dental abrasion is suspected to occur. This can be accomplished by starting from an unformed tray 72 that has regions of different thickness. For example, the material covering the bite line could be made thicker uniformly or only in specific areas, such as the molar region.
[0054] In the preferred embodiments the appliance according to the invention is based on a thermo-plastic polymer with low compressibility. The polymer softens when heated to temperatures above 50° C., allowing it to be conformally fitted to the dentitions. The physical properties of this thermo-plastic polymer, such as compressibility, toughness, tensile strength, pliability, and melting point can be adjusted by synthesizing the polymer with different molecular weight distributions (with mean molecular weight in the range of 20,000-80,000), or by incorporating nano-particles and other materials like bentonite clay nanoparticles modified by surfactants such as Stepantex SP-90, to get additional benefits, e.g. increased tensile strength, lower melting temperature, etc. In the preferred embodiment, the polymer is highly abrasion resistant thanks to its structure that contains interwoven strands 84 of polymer, as shown in a magnified scanning electron microscope image ( FIG. 1 ). Since these strands 84 are interwoven and extend deep into the material, they will not easily be pulled out or removed from the material during grinding of teeth, thereby making the appliance more abrasion resistant.
[0055] The shape of the unformed tray 72 facilitates the fitting of the softened material by being wide enough to cover all teeth and wrap around them, and by being narrow enough not to cause pressure on the teeth when the fitted mouth guard 10 cools off and contracts around the teeth. In contrast to athletic fitted mouth guards, night grinding fitted mouth guards are used for 6-10 hours straight, and therefore need to be extremely comfortable to guarantee compliance to use them during an entire night's sleep. The carefully designed shape, with cusps 28 , 38 and lobes 42 prevents the material from folding when the soft material is molded up against the teeth. The width of the dental unformed tray has also been carefully designed to cover the curved occlusal line portion 24 with solid material without perforations and still allow the user to mold the material up on the inside and outside of each tooth. This design will make sure that the fitted device grips around the teeth and does not fall out during sleep, and at the same time not extend up to the gum line, which is uncomfortable, nor to the hard palate on the inside, which can create gagging. It extends back to the molars, just enough to avoid contact between lower and upper dentitions, but it is short enough to avoid unnecessary gagging. The thinness and the exact design of the unformed dental tray 72 and the location of the perforations 50 , 56 allow the material to mold conformally around any uneven surface of the teeth. FIG. 3 shows an example of a fitted appliance.
[0056] Due to the ease with which the material can be formed and manipulated, the user can fit the mouth guard 10 on site or at home without assistance of health professionals. Fitting is superior due to the distinct properties of the polymer (thin and pliable at moderate temperatures), and to the design of the unformed dental tray 72 with strategically placed perforations 50 , 56 , as described above, and lobes 42 and cusps 28 , 38 as described above. These properties permit the user to place and fit the heated, softened material over the dentition through a rapid process wherein the material is sucked onto the teeth. In particular, the perforations 50 , 56 enhance the effect of the suctioning by allowing the user to create a negative pressure between the teeth and the material, thus sucking the material down to every irregularity of the teeth. Thanks to the perforations 50 , 56 in the guard 10 , the suctioning maneuver creates a minimal dead space between the material and the teeth, thus leading to a perfect, conformal fit. Without such perforations 50 , 56 , conformal fitting cannot be done since not enough negative pressure can be built up between a solid material and the dentition. This is reflected in the instructions of conventional fitted mouth guards, where the user is directed to apply downward mechanical pressure on the material, from outside with the fingers, to force the material to come closer to the teeth.
[0057] Polymer-based guard 10 according to this invention are inexpensive and disposable thereby improving oral hygiene. Users can move their jaws in any way without risking the guard 10 becoming dislodged.
[0058] The guard 10 can be re-shaped to optimize fitting by re-heating to the softening point and repeating the fitting. The superior fit of the guard 10 also results in the need for less material on the inside of the teeth, which in turn reduces gagging and improves comfort.
[0059] Users of the inventive guard 10 can breathe more easily. There is more room in the mouth since the guard 10 is considerably thinner than prior art dental appliances, and air can also move freely though the perforations.
[0060] In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope. | Disclosed is a dental appliance composed of a thermo-plastic polymer with low compressibility, high toughness, and high tensile strength, with a low softening point. The appliance has perforations that enable it to be easily custom-fitted by the user or a health professional. The appliance begins as a generally U-shaped, unformed dental tray that is significantly thinner than existing dental appliances. Once fitted, the dental appliance provides superior protection against damage to the enamel of the teeth and abrasion of the teeth due to bruxism or other mechanism leading to biomechanical wear of dental surfaces. The perforations facilitate the custom-fitting process by allowing the user to suck air through the perforations, thus applying a negative pressure between the material and the teeth while the material is still soft and pliable. This enables a user or health professional to within minutes create a final product that rivals the quality and fit of an appliance made by dental laboratories using dentist made impressions. | 0 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a preform in order to produce a thin wall container without a protrusion such as a screw or a support ring and the like around a neck portion and also relates to a packaging container made from the preform by stretch blow molding.
[0003] 2. Prior Art
[0004] According to the conventional preform of a cup like container, a tiny protrusion is formed on the side surface under the flange of the open end edge and a falling out of the preform from a neck mold is prevented by the protrusion, while the preform is pulled out from an injection core (reference patent 1: Japanese Utility Model Publication 4-20012, Pages 1-2, FIGS. 1 to 3).
[0005] A protrusion such as a screw or a support ring and the like on the outer side surface of a neck portion is formed by a neck mold as a preform for a packaging container which is formed to a thin wall other than the neck portion by the stretch blow molding and a bottle and the like which requires a cap to seal tightly, and the neck portion of the preform is formed by the neck mold for the outer side and an injection core for the inner side. Since the preform is in the state of being caught with the protrusion in the neck mold after the injection molding, while the injection core is being pulled out from the preform, the neck mold works as a holding mold to prevent from falling out of the neck mold with the injection core. Therefore, the prevention of the falling out of the preform is not necessary to be considered particularly.
[0006] However, as for a preform for a thin wall container molded by stretch blow molding for a packaging container which has a open end edge with a flange, being sealed by adhering with aluminum seal and the like, for example containers widely used for food application such as a lactic acid drink or foods having viscous property has no protrusion other than the flange of the open end edge formed between the neck mold and a base portion of the injection core, and also, there is nothing on the preform to be held by the neck mold, and when the injection core is pulled out after the injection molding, a phenomena presents that the preform is fallen out from the neck mold while adhering to the injection core.
[0007] According to the conventional technology described in the reference patent 1, as the prevention measure for the falling out, on the side surface under the flange of the open end edge of the preform, a tiny protrusion which engages the preform with a holding mold (neck mold) is formed between the holding mold and an injection mold, and the protrusion is eliminated during the expansion of the preform while being stretch blow molded into a cup. However, although the prevention measure is effective for the case of molding a cup like container by stretch blow molding a preform of which the wall is formed thick from the bottom portion to under the flange of the open end edge according to the reference patent 1, the protrusion becomes solid state in the normal molding which a mold release of the preform is conducted after the neck portion becomes the solid state because the position of the protrusion is between the neck portion and the stretch portion, and even a tiny protrusion, it is difficult to be eliminated completely by expansion at blow molding. A part of the protrusion left on the outer surface of the container causes to be a defective product, so that it is a problem that the above mentioned prevention measure can not be adopted for molding a thin wall container of making the mold release after the neck portion becomes a complete solid state.
SUMMARY OF THE INVENTION
[0008] The present invention is devised to solve the above mentioned problem of the conventional technology, and its purpose is to provide a new preform and a thin wall container by using a preform, comprising a neck portion having a thin wall portion and a thick wall portion which can be as the neck portion of the thin wall container without modification, thus both thinning the neck portion of the preform by the thin wall portion and keeping the strength by the thick wall portion can be accomplished, and also, the preform being prevented from falling out from the neck mold.
[0009] The present invention relates to a preform comprising,
[0010] an open end edge formed as a flange overhanging outwardly, a circular neck portion formed under said open end edge by a neck mold for an outer side of said neck portion and an injection core for an inner side of said neck portion, and closed bottom portion, wherein;
[0011] an outer peripheral surface of said circular neck portion is formed by the neck mold to a chamfered form having a thin wall portion and a thick wall portion alternately arranged at regular intervals, and a lower end edge of said thin wall portion is formed as an engagement portion with the neck mold.
[0012] A thin wall container according to the present invention has a thin wall body formed by stretch blow molding the lower portion from the lower end edge of the thin wall portion of the neck portion of the above mentioned preform.
BRIEF DESCRIPTION OF THE INVENTION
[0013] [0013]FIG. 1 is a side view of a preform (solid line) and a thin wall container (chain line) according to one embodiment of the present invention.
[0014] [0014]FIG. 2 is an A-A sectional view as figure (A) and the enlarged view as figure (B) of FIG. 1.
[0015] [0015]FIG. 3 is a longitudinal sectional view of an injection mold, a neck mold, and an injection core in the molding state of the preform.
[0016] [0016]FIG. 4 is a sectional view of a thick portion of a neck mold and a neck portion.
[0017] [0017]FIG. 5 is a sectional view of the thin portion of the neck mold and the neck portion.
[0018] [0018]FIG. 6 is a longitudinal sectional view of the neck mold, a stretch rod and the preform in the state of mold closing of a blow mold.
DETAILED DESCRIPTION OF THE INVENTION
[0019] In the above mentioned structure of the preform of the present invention, since the neck portion and the neck mold are tightly engaged by the lower end edge of the thin wall portion formed by chamfering at regular intervals in the outer peripheral surface of the neck portion, even though the neck portion is stuck to the injection core, the preform is separated from the injection core by the force of pulling out the core, so that the preform is left in the neck mold, and falling out of the preform from the neck mold while pulling out the injection core is eliminated.
[0020] Also, the neck portion comprises the thin wall portion and the thick wall portion having the thickness gradually increase and decrease alternately created by chamfering the outer peripheral surface of the neck portion. Even if the thin wall portion is formed at regular intervals, since the thickness of the thin wall portion gradually increases toward the thick wall portion, a flow resistance of resin through the thick wall portion during the injection molding is small, and no weld is created in the neck portion caused by the thin wall portion.
[0021] Also, since the neck portion is formed as the neck portion of container at molding a preform, sometimes the thickness of the neck portion is formed thinner wall than usual case depending on containers. In such case, the thin wall portion by chamfering can be formed, and even the gaps of the lower end edges of the thin wall portion are small, the gaps positioned at regular intervals in the outer peripheral surface can hold engagement of the neck portion with the neck mold, and falling out from the neck mold of the preform while pulling out of the injection core can be prevented without a limitation of the neck portion thickness.
[0022] Moreover, as for the stretch blow molding of hot parison method, a release of the preform from the mold is conducted in the early stage while in high temperature, but the release is done after the neck portion being cooled to the solid state. In the preform of the above mentioned constitution, since the thin wall portion accelerates the neck portion to be solid with cooling by the neck mold, the time required to for injection molding a preform is shortened, and the release of the preform from the mold can be conducted earlier, so that it contributes to reduce the molding cycle time.
[0023] Also, as for the container of the above mentioned constitution, the neck portion is partially thin by the thin wall portion, but as the thin wall portion is reinforced by the thick wall portion arranged at regular intervals, the deformation of the open end edge is prevented because the neck portion resists to the tensile or holding force applied to the open end edge at the stage of filling the contents or of delivery, and since the neck portion supports the open end edge while making closure by an adhesion of covering member such as aluminum sheet and the like, sealing with the covering member can be easily conducted.
[0024] In FIG. 1 and FIG. 2, a reference numeral 1 is a closed end preform made by injection molding comprising a circular neck portion 4 integrally, continuing into a cylindrical body portion 3 under an open end edge 2 having an outwardly overhanging flange. The outer peripheral surface of the neck portion 4 is chamfered at regular intervals of 30 degree so as to leave a thick wall portion 6 with the thickness (e.g.: 0.25 mm). Thus, the neck portion 4 constitutes of a thin wall portion 5 and the thick wall portion 6 which have alternately increase and decrease of the thickness gradually, and at least a lower edge 5 a of the thin wall portion 5 is used as the engagement portion with the neck mold, which is described below.
[0025] A numeral reference 30 is a container having a thin wall body portion 31 formed by stretch blow molding the preform 1 , and the open end edge and neck portion comprises the same structure with the preform 1 .
[0026] In FIGS. 3, 4 and 5 , a reference numeral 10 is an injection mold to form an outer surface of a body portion 3 and a bottom portion of the preform 1 , and an injection nozzle 11 is in nozzle touch state to a cavity gate of the bottom portion of the mold. A reference numeral 12 is the neck mold serving both a holding mold and forming the neck portion 4 of the preform 1 and comprises a pair of short cylindrical split cavity molds which are able to form the neck forming portion of circular hole in the inside of the lower end, and the neck mold 12 is provided under a transport platen 15 fixed with a holding plate 16 , movable for opening and closing to mate the split mold.
[0027] The neck forming portion of the above mentioned neck mold 12 comprises a concave surface 12 a which forms the thick wall portion 6 arranged at regular intervals of 30 degree on the neck portion 4 of the preform 1 by chamfering the inner peripheral surface of a circular hole and a convex surface 12 b which forms the thin wall portion 5 between the thick wall portions 6 alternately and continuously, and by the concave surface 12 a and the convex surface 12 b, the outer peripheral surface of the neck portion 4 is able to be chamfered at regular intervals.
[0028] A reference numeral 13 is an injection core forming the inside of the preform 1 , and it is integrally formed with a core body 14 inserted from upward into the neck mold 12 . An open end edge 2 of the preform 1 is formed between the gap around the injection core, formed between the core 13 and the core body 14 , and the neck forming portion of the neck mold 12 .
[0029] In FIG. 6, a reference numeral 20 is a blow mold which forms a blow cavity 22 by a closed state of a pair of split molds 21 movable for opening and closing. A reference numeral 23 is a stretch rod, and it is inserted to the center of a blow core 24 . A reference numeral 25 is a vertically movable bottom mold for the bottom portion of the blow cavity 22 .
[0030] After the above mentioned preform 1 is formed by injecting molten resin into a cavity (figure omitted) which is formed by the combination of an injection mold 1 , an injection core 13 , and a neck mold 12 , the preform 1 is released from an injection mold 10 by the upward movement of the neck mold 12 , and also the injection core 13 is pulled out by the upward movement of the core body 14 . On this occasion, the neck portion 4 sticks firmly to the injection core 13 inside by a shrinkage caused by cooling the resin, but as shown in FIG. 5, the convex surface 12 b of the neck mold 12 is in the fitting state with the neck portion 4 , and the neck mold 12 is engaged to the lower end of a thin wall portion 5 at regular intervals on the outer peripheral surface of the neck portion 4 , so the preform 1 and the injection core 13 are separated by a force of pulling out the injection core 13 , and the preform 1 is prevented from falling out with the injection core 13 .
[0031] The preform 1 which is released from the above mentioned injection mold 10 and the injection core 13 and continuously held by the neck mold 12 is transferred to the blow mold 20 in the state of mold opening with the neck mold 12 by a transfer palten 15 . Even in the case of this transfer, the convex surface 12 b of the neck mold 12 is in the fitting state with the outer peripheral surface of the neck portion 4 , and the lower edge 5 a of the thin wall portion 5 of the neck portion 4 and the neck mold 12 are connected, so that the preform 1 is prevented from falling out from the neck mold 12 by the inertia in the beginning of the transfer or stopping.
[0032] After the transfer, the preform 1 , as shown in FIG. 6, is positioned at the center of the blow cavity 22 by closing the blow mold 20 , accordingly the upper portion of the blow cavity and the neck mold 12 are closed, and moreover the blow core 24 is fitted to the neck mold 12 from upward, and a stretch rod 23 is inserted and positioned to the inside of the preform.
[0033] Subsequently, lower portion of the preform 1 , from the lower end edge of the thin wall portion of the neck portion 4 (figure omitted) is stretch blow molded, while being held in the neck mold 12 , by elongation of the stretch rod 23 and an air blow, and it is formed to be a thin wall container 30 comprising the open end edge 2 formed with a flange overhanging outwardly, the neck portion 4 which is formed under the open end edge 2 in circular form and which also comprises the thin wall portion 5 and the thick wall portion 6 having the thickness gradually increase and decrease alternately formed by chamfering on the outer peripheral surface of the neck portion having regular intervals, and a body portion 31 , equally with a shoulder portion and a bottom portion which are formed to thin wall. | The purpose of the present invention is to prevent a falling out of a neck portion of a preform without a protrusion such as screw or support ring from a neck mold of a preform. The present invention relates to a preform comprising an open end edge formed as a flange overhanging outwardly, a circular neck portion formed under said open end edge by a neck mold for an outer side of said neck portion and an injection core for an inner side of said neck portion, and closed bottom portion, wherein; an outer peripheral surface of said circular neck portion is formed by the neck mold to a chamfered form having a thin wall portion and a thick wall portion alternately arranged at regular intervals, and a lower end edge of said thin wall portion is formed as an engagement portion with the neck mold. | 1 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of copending U.S. patent application Ser. No. 11/218,096, filed Aug. 31, 2005, entitled, “METHOD AND APPARATUS FOR TRANSMITTING HIGH SPEED DATA BY SPECTRAL DECOMPOSITION OF THE SIGNALING SPACE”, which is a continuation of U.S. patent application Ser. No. 09/931,782 filed Aug. 17, 2001, entitled, “METHOD AND APPARATUS FOR TRANSMITTING HIGH SPEED DATA BY SPECTRAL DECOMPOSITION OF THE SIGNALING SPACE”, which is a continuation in part of U.S. patent application Ser. No. 09/021,137 filed Feb. 10, 1998 (Issued Jun. 4, 2002 as U.S. Pat. No. 6,400,776), entitled, “METHOD AND APPARATUS FOR HIGH SPEED DATA TRANSMISSION BY SPECTRAL DECOMPOSITION OF THE SIGNALING SPACE”. Each of the aforementioned applications is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention is generally directed to high-speed data communication, and more specifically, to the area of high-speed modem design. It relates to achieving high spectral efficiency in signaling systems.
BACKGROUND OF THE INVENTION
[0003] Modern telecommunication applications have resulted in substantial increases in the need for additional bandwidth. For example, in the area of wired communications, there is a need to simultaneously support voice, video, and data applications at low BER (Bit Error Rates) using new high-speed modem designs for twisted pairs. At signaling rates better than 10 Mbits/s performance bounds generally exceed a BER of 10 −6 . When the conventional Pulse Amplitude Modulation (PAM) technique is used, the baseband communication signal is represented by a series of modulated pulses whose amplitude levels are determined by the symbol to be transmitted. For example, with 16-QAM (Quadrature Amplitude Modulation), typical symbol amplitudes of ±1 and ±3 are utilized in each quadrature channel. For digital communication systems, efficient used of bandwidth is crucial when dealing with time-dispersive channel, as is common with wireless systems. In these types of systems, whenever there is distortion of the signals due to preceding or following pulses, normally referred to as pre-cursors and post-cursors, respectively, the amplitude of the desired pulse is affected due to superimposition of the overlapping pulses. This phenomenon is known as intersymbol interference, and is an impediment to high-speed data transmission, especially in systems that are constrained by limited bandwidth.
[0004] One way to minimize the effects of intersymbol interference is to use an equalizer. Fixed equalizers are designed to be effectively operated between an upper and lower bound between which the channel is expected to deviate. Whenever these limits are exceeded, the equalizer ceases to operate effectively. Hence, there has to be a certain degree of precision when channel equalization is employed, and fixed equalizers are implemented. There are adaptive equalizers (i.e., continuous) that track dynamic channel dispersion and make continuous adjustments to compensate for such intersymbol interference. This provides some improvement in performance over the fixed equalizer.
[0005] Incorporation of the equalizer into some communication systems does not come without penalty. In wireless systems, for instance, insertion loss becomes a critical factor if the equalizer is present and the associated impairment does not occur. The main purpose of the equalizer implementation is to enhance the information bearing capability of the communication system with the design objective of asymptotically approaching the capacity bounds of the transmission channel. Consequently, the use of the equalizer can be regarded as one instance of an array of possibilities that may be implemented to enhance the bit rate of the communication system design.
SUMMARY OF THE INVENTION
[0006] In accord with the invention, a method and apparatus is provided that makes more efficient use of the available signaling bandwidth in the sense of asymptotically approaching possible transmission limits. This is done by significantly reducing the effects of intersymbol and interchannel interference by a judicious choice of the signaling pulse shapes. In particular, prolate pulses are used to extend channel capacity and reduce interference. By use of orthogonal axes that span the signal space, combined with water filling techniques for efficient allocation of transmission energy based on the noise distribution, the information content can be increased without increase in bandwidth.
[0007] The signaling space is spectrally decomposed to support the simultaneous transmission of multiple signals each with differing information bearing content. These signals being orthogonal, are non-interfering. Signals are constructed as complex sets and are generally represented with axial coordinates, all orthogonal to one another within the complex plane. The real axis is termed the in-phase (I) component and the imaginary axis is termed the quadrature (Q) component. Each component defines a spanning vector in the signal space.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a graph depicting the concentration of energy in a prolate pulse interval;
[0009] FIG. 2 is a block schematic illustrating an optimized modem using the invention;
[0010] FIG. 3 is a block schematic of a Single Segment Discrete Prolate Transmitter;
[0011] FIG. 4 is a graph illustrating the application of water filling to the present invention.
[0012] FIG. 5 is a graph depicting channel segmentation and use of the frequency response; and
[0013] FIG. 6 is a block schematic of the Discrete Prolate demodulator corresponding to FIG. 3 .
DETAILED DESCRIPTION
[0014] Spectral efficiency in digital systems is largely a function of the wave shapes of the signals that are used to carry the digital information. There are tradeoffs between time limitations and frequency limitations. These two requirements generally have a flexible relationship. The characteristics of prolate pulses may be chosen to limit spectral energy dispersion thereby permitting more signaling channels for a given bandwidth. These advantages become readily apparent with an analysis of the prolate pulse spectral performance. In particular, the Fourier transform of the waveform is very band limited. Proper selection of signal space such as axes or spectral vectors representing signal coordinates are very important. If signals are orthogonal to one another, transmission techniques utilizing methods of water filling may be implemented with significant increase in efficiency. The technique of water filling is discussed in “Multicarrier Modulation for Data Transmission: An Idea Whose Time Has Come”, J. A. C. Bingham, “ IEEE Communications ,” May 1990, pp. 5-14 incorporated by reference. An illustration of water filling may be ascertained from the graph of FIG. 4 . A bandwidth of a channel is defined by the marks 401 and 402 on the horizontal axis. The curve 403 defines the noise level produced as seen by a receiver. The energy level, which the channel can transmit, is defined by the horizontal level 404 . The area 405 bounded by the curve 403 and energy level 404 may be “water filled” by data signals. The data acceptance area 405 of the band is divided into sections 408 by vertical dividers 409 . The signal data is inserted into a section until the added data and noise in that section reaches the energy level limit. This filling combined with the orthogonal nature of the data signals inserted in the sections permit the increase in the data capacity of the channel.
[0015] Consider a trigonometric polynomial p i (t) defined as follows:
[0000]
p
i
(
t
)
=
∑
n
=
-
N
N
a
in
j
n
π
t
(
1
)
[0016] In equation (1) the period may be chosen to be 2 by suitable scaling of t. The coefficients a in can be obtained by an optimization process, the objective of which is to obtain a spectrally efficient pulse. The process may be regarded as a scheme in which the energy of the pulse is concentrated in the interval [−ε,ε]. This is shown in FIG. 1 where a more or less generic pulse 101 is shown and the constraining interval 102 is indicated. The optimization process is a transmission pulse design problem, and a particular mathematical approach for achieving this objective is now described. In general, optimal communication system design requirements often necessitate the transmission of spectrally efficient pulses in order to minimize both intersymbol interference and interchannel interference where application requires segmented spectrum utilization.
[0017] Based on the specified format in equation (1), it can be shown that the coefficients a in , of p i (t) satisfy the following system of equations:
[0000]
∑
m
=
-
N
N
sin
(
n
-
m
)
πɛ
(
n
-
m
)
ɛ
a
im
=
λ
a
in
,
n
=
-
N
,
-
N
+
1
,
⋯
N
.
(
2
)
[0018] Equation (2) may be rewritten in the form,
[0000] S{right arrow over (a)} i =λ i {right arrow over (a)} i (3)
[0019] Where the coefficients S nm of the matrix S defined by equation (3), and eigenvectors {right arrow over (a)} i are given by,
[0000]
S
nm
=
sin
(
n
-
m
)
πɛ
(
n
-
m
)
ɛ
(
4
)
[0000] and
[0000] {right arrow over (a)} i =[a −Ni ,a (−N+1)i , . . . a 0i , . . . , a (N−1)i ,a Ni ] (5)
[0020] Where t denotes transpose. The matrix S is a real, symmetric, and positive definite with other mathematical properties of interest to the development, as now discussed. There are thus 2N+1 real eigenvalues λ i which satisfy (3) and which may be ordered such that:
[0000] λ 1 >λ 2 > . . . >λ 2N+1 (6)
[0021] For each eigenvalue λ i , there is an associated eigenvector {right arrow over (a)} i , whose coefficients can be used to form the trigonometric function defined in equation (1). The eigenvectors of the matrix S may be normalized to have unit energy. Because of the orthogonality of the eigenvectors of symmetric matrices, their dot products {right arrow over (a)} i •{right arrow over (a)} j satisfy the following relationship,
[0000]
a
⇀
i
·
a
⇀
j
=
∑
n
=
-
N
N
a
in
a
jn
=
δ
ij
,
(
7
)
[0022] Where δ ij is the Kronecker delta function. Because of equation (3) and equation (7), it can be shown that functions of the form of equation (1) whose coefficients are those of the eigenvectors of the matrix S as defined in equation (4), the following relationships holds:
[0000]
1
2
∫
-
I
1
p
i
(
t
)
p
j
(
t
)
t
=
δ
ij
,
(
8
)
[0000] and,
[0000]
1
2
∫
-
ɛ
ɛ
p
i
(
t
)
p
j
(
t
)
t
=
λ
i
δ
ij
(
9
)
[0000] Functions so formed are described as discrete prolate.
[0023] With the background material discussed above, a particular method of communicating digital information using the functions p i (t) defined earlier is now presented. Again, in view of equation (6), there are 2N+1 eigenvectors that satisfy equation (3). The vectors together form a spanning set for the vector space defined by the matrix S. Define D to be the dimension of the associated vector space. Then D is given by:
[0000] D= 2 N+ 1 (10)
[0024] Note that D is a design parameter, and is a function of N. By analogy, {p i (t)} form a spanning set for the signal space associated with the matrix S, and this signal space is also D dimensional. Consider the construct:
[0000]
x
i
(
t
)
=
∑
k
=
-
∞
∞
I
k
p
i
(
t
-
kT
)
(
11
)
[0025] Generalizing and using equation (8), it can be shown that the following holds:
[0000]
1
2
T
∫
-
T
+
kT
T
+
kT
x
i
(
t
)
p
j
(
t
)
t
=
δ
ij
I
k
(
12
)
[0026] Equation (12) is of critical importance to the invention. The implications are that if a function of the form of equation (11), for a specific value of i, is transmitted over a communication channel, then the transmitted alphabet I k will only be uniquely determined in an interval defined by k if the corresponding p i (t) is used as the receiving filter. If a function of the form of equation (11), for a specific value of i, is transmitted over a communication channel, and p j (t) for j≠i, is used as the receiving filter, then the function p i (t) will be virtually non-existent. Thus in order to extract the information content of a signal whose format is given by equation (11), the signaling pulse must be matched at the receiver. In anticipation of making reference to Cartesian space, the format of equation (11) is used in the construction of y i (t) defined as follows:
[0000]
y
i
(
t
)
=
∑
k
=
-
∞
∞
Q
k
p
i
(
t
-
kT
)
(
13
)
[0000] where again Q k is the alphabet to be transmitted. It is clear that equation (13) also satisfies a relationship similar to equation (12). Equations (11) and (13) can now be used to quadrature modulate a carrier in the final part of the transmission signal synthesis. Define s i (t) by:
[0000] s i ( t )= x i ( t )cos(2 πf c t )− y i ( t )sin(2 πf c t ) (14)
[0027] Thus, the signals are constructed as complex sets and are generally represented as vectors within the complex plane. The real axis is termed the in-phase (I) component and the imaginary axis is termed the quadrature (Q) component.
[0028] As indicated by equation (10), there are D such constructs possible. Because of the Orthogonality of the building blocks {p i (t)} discussed earlier, {s i (t)}, being linear combinations of a single p i (t) for each i, are themselves orthogonal, forming a spanning set for the signal space defined over the channel band limited by W=1/2T. That is to say, each such signal s (t) may be regarded as an orthogonal “finger” over which the symbols {I k , Q k } may be independently transmitted. Thus, equation (14) can be used to increase the bit rate of the communication channel without bandwidth expansion. Of course coding and equalization may be added to improve fidelity.
[0029] The parameters ε and N determine the spectral shape of the transmission pulses p i (t). In general ε will be used to determine the compactness of the fit within the signaling period, while N determines the peaking and roll-off. It is important for N to be fairly large (N≧10) as there are at least two benefits to be gained in this regard. Firstly, large values of N contribute to better roll-off characteristics, which directly minimize intersymbol interference. Secondly, as can be seen by equation (10), large values of N contribute directly to an increase in the dimension of the signaling space, providing more discrete prolate functions that can be used to increase the capacity of the transmission system design. However, these benefits must be balanced by the fact that tighter peaks that are made possible by larger values of N are likely to place greater implementation constraints on the receiver, to the extent that more accurate symbol timing shall be required to retrieve the encoded digital information.
[0030] In general, the range of values that can be taken on by the discrete symbols {I k , Q k } determines the number of levels M that may be reasonably distinguished at the receiver, with noise, crosstalk, and interference playing a critical role in the process. Conventional modulation techniques, such as QAM for instance, may be referenced, and the value of M shall be determined in an optimization process in which the power is held constant, and the bit rate is maximized for a given BER constraint. Given M, the information bearing capacity C of the transmitter is computed in a straightforward manner. Thus,
[0000]
C
=
log
2
M
T
(
15
)
[0031] Where C is given in units of bits/s. Equation (15) holds for the one-dimensional case. That is, only when one signal of duration T having M reasonably distinguishable levels is transmitted in a channel bandlimited by W. However, when multiple orthogonal signaling is used for data transmission, the parameter M in equation (15) will be a function of the number of signals chosen, along with the associated levels that may be represented by each independent choice. A limiting reformulation of equation (15) is now given by:
[0000]
C
lim
=
log
2
∏
i
M
i
T
(
16
)
[0032] Equation (16) hints of the possibility of channel optimization with more efficient encoding of the signaling data. A concrete use of equation (16) is demonstrated in the sequel, specifically, with the aid of FIGS. 3 and 6 .
[0033] The area of optimal communication system design is generally one in which various signal-processing techniques are comprised to asymptotically approach theoretically established channel capacity limits. Transmission rates may further be optimized if a process known as water filling is implemented. With the implementation of water filling, the available signaling power is allocated to the communication channel, and the bits are loaded in a manner related to the noise spectral density, with the objective of maximizing resource utility. It may be regarded as a process in which the squander of the available signal energy is avoided. Let the noise be Gaussian, with the power spectral density given by N(f), with H(f) being the associated complex transfer function of the channel. Then, in order to make efficient use of the available signaling power S, the optimal channel input power is given by:
[0000]
S
=
∫
f
∈
Ω
B
-
N
(
f
)
H
(
f
)
2
f
(
17
)
[0000] where the region of integration Ω is defined by:
[0000]
Ω
=
{
f
:
N
(
f
)
H
(
f
)
2
≤
B
}
(
18
)
[0034] Equations (17) and (18) describe the elastic relationship that exists between the power spectral densities of the input signal and the noise during the process of optimizing the available channel bandwidth. In equations (17) and (18) B is an average input power constraint.
[0035] From a practical standpoint, the optimal allocation of signaling power is best achieved by channel segmentation. Then, the allocation of bits to the various sub channels is achieved through the process of maximizing the channel capacity while minimizing the baud error rate. There exist in the literature a variety of optimal loading algorithms through which the required energy distribution may be accomplished. A good example may be found in patents: “Ensemble Modem Structure For Imperfect Transmission Media” U.S. Pat. Nos. 4,679,227, 4,732,826 and 4,833,706.
[0036] With the aid of FIG. 5 , an exemplary approach to optimized loading is now discussed. Let the available channel bandwidth be divided into N equal segments of length W. Assume that the frequency response within the i th segment is flat and given by H i (f). Let the noise be additive white Gaussian with double-sided spectral density N o /2 watts/Hz. Let the available signal power P be equally divided among all sub channels available, and normalize the system to the first sub channel. The received power in the i th sub channel is thus P i =l i P/N where l i =|H i (f)| 2 /|H i (f)| 2 . It can then be shown that a possible optimal choice of bit loading n i is given by:
[0000]
n
i
=
log
2
{
l
i
/
N
)
(
3
/
2
)
(
P
/
N
o
W
)
-
ln
Pr
(
ɛ
)
}
(
19
)
[0037] Where n i is the number of bits allocated to the i th sub channel, and Pr (E) is the probability of symbol error for all sub channels. In equation (19), since l i P/N o W is the signal to noise ratio in the i th sub channel, a preferred embodiment of the invention will use a measured value of the noise in the i th sub channel for the computation of n i . This combined approach to the allocation of signaling energy and of bits to each sub channel comprises a specific optimal approach to water filling.
[0038] A block diagram of the complete transmitter/receiver pair is shown in FIG. 2 . In FIG. 2 the transmitter comprises N sub-transmitters 201 - 1 to 201 -N and the summer 202 . Input data for transmission through the channel are modulated at each sub-transmitter 201 - 1 to 201 -N, and the outputs are summed at the summer 202 for transmission through the channel characterized by the function block 203 . Addition of noise into the system is depicted by function block 204 in FIG. 2 . The i th sub-transmitter 201 - i is optimized in accord with water filling as described above for the i th segment of the channel. Similarly, the receiver is comprised of N subcomponents 205 - 1 to 205 -N, the i th subcomponent 205 - i corresponding the component 201 - i of the transmitter.
[0039] The invention is now further described with greater specificity with the use of FIG. 3 , which illustrates how the discrete prolate functions are used for capacity optimization. With reference to function block 201 - 1 , assume that, with the use of equation (19), a computed value of 6 was obtained for n 1 . It is clear from the foregoing discussion that this loading bound can be assured through the resolution of the transmitted signal with the use of two discrete prolate functions. Let n 1 =n 11 +n 12 with n 11 =2 and n 12 =4. It can further be shown that, given the specific choices for n 11 and n 12 , if it is assumed that the symbol error is equal in both signaling dimensions, the power must be divided such that P 1 =P 11 +P 12 , where P 11 =P 1 /3 and P 12 =2P 11 . Given the foregoing choices of parameters, an exemplary embodiment of the invention in function block 201 - 1 is illustrated in FIG. 3 . As can be seen from the figure, the six bits to be transmitted are segmented at function block 301 into 2- and 4-bits packets that are sent to function blocks 302 - 1 and 302 - 2 . At function block 303 - 1 , a 4-level I/Q mapper is used, while a 16-level mapper is used at function block 303 - 2 . Within function block 304 - 1 the I and Q components from function block 303 - 1 and the power P 11 are used to generate the in-phase and quadrature components of the prolate pulses corresponding to p 1 (t). Further, these components are modulated at function block 306 - 1 and 308 - 1 , then summed at function block 309 for output to the channel. As can be seen from FIG. 3 , similar activities occur for the dimension corresponding to p 2 (t)).
[0040] The structure of the optimized sub-receiver 205 - 1 , associated with sub-transmitter 201 - 1 , is shown in FIG. 6 . As discussed earlier, the key to retrieving the bits that were sent in a particular dimension is the use of a low pass eigenfilter for that dimension. The discrete prolate pulses are thus used to form a low pass orthogonal filter bank for extracting the bit information from each dimension. The demodulated I k and Q k values finally go through a reverse mapping process, after which the original block of bits is reconstructed.
[0041] In the receiver of FIG. 6 the channel output is received as indicated by the block 601 . This channel output is connected to a plurality of mixers 603 - 1 , 603 - 2 , 605 - 1 and 605 - 2 and are mixed with cosine and sine signals, respectively. These mixed signals are demodulated in the orthogonal filter bank containing filters 606 - 1 , 606 - 2 , 606 - 3 and 606 - 4 . I/Q reverse mappings are performed in reverse mappers 607 and 608 to recover the segmented bits and the originally transmitted bit pattern is reconstructed in block 609 . While discrete blocks are illustrated, the processes are stored program processes that are performed independently of block identification.
[0042] Synchronousness being of critical significance to the design of telecommunication systems, reference is now made to the fact that in the construction of FIG. 2 , FIG. 3 , and FIG. 6 , this requirement is stipulated. Thus, in a complete embodiment of the present invention, methods of carrier tracking and symbol recovery shall be implemented. There are various procedures well documented in the literature to accomplish these operations. One reference describing synchronism with respect to carrier tracking and symbol recovery is the text “Digital Communications, Fundamentals and Applications” by Bernard Sklar. Information specifically related to synchronization may be found in chapter 8, Pages 429-474.
[0043] Recall that in equation (2) ε was used to determine the pulse efficiency. Thus, in a preferred embodiment equation (9) may be used to shorten the length of the filtering process, in an effort to seek implementation efficiency. Filtering must then be normalized by a factor of 1/λ i for each finger. In this case, keeping jitter to a minimum will be a critical issue.
[0044] In present-day communication systems, because of the inefficiencies that occur with the application of a single signal for information bearing, the implementation of complex equalization structures is imperative to achieve the most efficient use of the channel. With the implementation of the design discussed herein, the equalizer shall effectively be reduced to a simple scaling function.
[0045] The invention presented herein was described in light of a preferred embodiment. It should be understood that such preferred embodiment does not limit the application of the present invention. Persons skilled in the art will undoubtedly be able to anticipate alternatives that are deemed to fall within the scope and spirit of the present application. | A method and apparatus of high speed multi-dimensional signaling via a modem has a processing method of utilizing prolate pulses to optimize the transmission capacity of the channel. The modem includes a process that segments the channel bandwidth and allocates the power and bit loading in relation to a measure of the noise in each spectral bin. Data are carried over a plurality of frequencies across the channel, and within each spectral bin, a plurality of orthogonal signaling dimensions. | 7 |
TECHNICAL FIELD
[0001] The present invention relates to virtual machine platforms including a plurality of virtual machines, each respectively connected to each of a plurality of separate computers and particularly to power management for such virtual machine platforms.
BACKGROUND OF RELATED ART
[0002] In the past ten years, with the great increase in World Wide Web (Web) systems, the computer processing power required by an organization has grown exponentially each year so that now hundreds and even thousands of servers are required. This has led to a resurgence of larger and larger mainframe computers. Particularly mainframe and like large computers operating in a virtual machine (VM) mode in which multiple instances of an operating system and associated application program reside in the same physical hardware. Such virtual machines have been satisfying the needs for the large number of servers that are often arrayed as virtual machine server farms. For further background, attention is directed to the article: Virtual Linux servers under z/VM: security, performance, and administrative issues, D. Turk, published in the IBM Systems Journal, July 2005; and to the article: More POWER to Ya, Expanded Virtualization Manager capabilities help customers grow and manage virtualized environments, Jim Fall, published in the IBM Systems Magazine, September 2007.
[0003] In such virtual machine environments wherein multiple user computers are connected to each virtual machine platform providing a plurality of virtual machines respectively connected to these multiple users, power management is difficult to control. Full power is required at each virtual machine platform prior to the initiation of a virtual machine session. Since the virtual machine platform must always be available to remote user computers that need to access appropriate virtual machines, it has been customary to continuously operate any online platform in a full power mode. The wasted power consumption becomes particularly pronounced when the virtual machine platforms are arrayed as virtual machine server farms.
SUMMARY OF THE PRESENT INVENTION
[0004] The present invention addresses the power consumption problem of maintaining each virtual machine platform in a full power mode even when there are no user computers connected to the virtual machine platform in an active mode.
[0005] To this end, the present invention provides a system, method and computer program for power management in a virtual machine environment that includes at least one physical virtual machine platform providing a plurality of virtual machines, and a plurality of separate (user) client devices each connected to a respective one of the virtual machines in a typical virtual machine distribution environment. Client devices are understood to include user computers and computer subsystems, including printers, disk drives and serial ports, among others. In the description of the following invention, when the term user computer is used, it is intended to include all such client devices.
[0006] There is also provided a function, independent of the connections of the user computers or client devices to the virtual machines, for determining if each of said client devices connected to the virtual machines is in an active state together with a function for switching the virtual machine platform into a reduced power consumption state in the platform when all of the user computers connected to the virtual machines are in a non-active state.
[0007] In preferred operations, the implementation of this invention is when the plurality of user computers are remote from the virtual machine platform, and there are networks, usually the Internet or Web (these two terms are used interchangeably in this description) for respectively connecting the plurality of user computers to the virtual machine platform.
[0008] As set forth above, the present invention is particularly advantageous in systems, e.g. virtual server farms, wherein there are a plurality of the virtual machine platforms, each platform respectively providing a plurality of virtual machines, together with a plurality of user sets, each user set including a plurality of user computers or devices respectively connected to the virtual machines in one of the plurality of virtual machine platforms, so that the means for switching switch a respective one of the virtual machine platforms into a reduced power consumption state when all of the user computers or client devices connected to virtual machines in the respective one platform are in a non-active state. Such an implementation may be effectively used when the plurality of the virtual machine platforms provide servers arranged as a virtual server farm, and each of the plurality of sets of user computers are client devices or user computers connected to the virtual machines in the respective servers.
[0009] As will be hereinafter set forth in greater detail, in a preferred embodiment of this invention, the implementation for switching the virtual machine platform into the reduced power state is in the virtual machine platform and the means for communicating whether each of said computers are in a non-active state are connected to the means for switching by a path independent of an operating system of said virtual machine platform. This path for communicating the non-active state is connected to the Basic Input Output System (BIOS) firmware of the virtual machine platform by a route independent of said hypervisor of the platform. In such an arrangement, the virtual machine platform includes a baseboard management controller (BMC) having a function for tracking the non-active states of the connected user computers and the path for communicating the non-active state is connected to the BIOS through the BMC.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will be better understood and its numerous objects and advantages will become more apparent to those skilled in the art by reference to the following drawings, in conjunction with the accompanying specification, in which:
[0011] FIG. 1 is a generalized diagrammatic view of a network portion, including a single representative virtual machine platform and a set of remote user computers or client devices connected to virtual machines in the platform to illustrate the non-active state monitoring of the user computers;
[0012] FIG. 2 is a diagrammatic view like that of FIG. 1 showing a plurality of virtual machine platforms respectively connected to a plurality of sets of user computers;
[0013] FIG. 3 is a general flowchart of a program set up to implement the present invention for power management in a virtual machine environment; and
[0014] FIG. 4 is a flowchart of an illustrative run of the program set up in FIG. 3 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Referring to FIG. 1 , there is shown a generalized diagrammatic view of a network portion, including a single representative virtual machine platform 20 , and a set of remote user computers, i.e. client devices, Desktops 1 , 2 and n connected via network 10 , e.g. the Web, and respective servers S 1 , S 2 and Sn, to virtual machines, VM 1 , VM 2 and VMn in the platform, using operating systems OS 1 , OS 2 and OSn.
[0016] The assignment of specific virtual machines, VMs to specific user computers, desktops 1 through n, is allocated by hypervisor 21 , the virtual machine platform supervisor. The hypervisor manages the multiple operating systems, OS 1 -OSn, as well as the platform's processor, BIOS 22 , memory and other resources as required. Since this is a virtual machine platform, the hypervisor may be considered to be a virtualization manager. Current conventional VM connection brokers (not shown) operate to assign the currently running virtual machines on platform 20 to specific client devices illustrated by user desktops 1 to n. However, such connection brokers are only involved in the login and disconnect processes. Thus, if a particular desktop 1 , 2 or n logs in and then is idle, the particular assigned VM and its associated resources in the virtual machine platform 20 remain fully powered irrespective of the non-activity of assigned user desktop 1 through n computers.
[0017] Accordingly, the present invention provides an implementation independent from the operating systems and the hypervisor 21 of the platform 20 to detect non-activity of the allocated user desktop 1 - n computers. Thus, in the environment of FIG. 1 , the hypervisor, which may be commercially available in a VMware, Citrix or Calista environment, has an individual software component working with hardware compression engines that allow the multiple users (desktops 1 - n ) to access the same platform 20 . Thus, when the platform hardware is powered on, the hypervisor allocates memory resources specific for that user. When the user no longer requires the resources, e.g. logs off, the resources are released back into the platform pool. However, the platform 20 remains fully powered on and fully functional, even though the platform is no longer required.
[0018] The present invention, as will be hereinafter described in greater detail, provides for putting the platform into a lower power consumption state when virtual machine resources (processor, memory, operating system and application software) are no longer required by the user computers o client devices, i.e. all are in the non-active state; but when a user computer or client device does require the use of a VM supported by the platform, i.e. the user computer becomes active, the platform 20 exits the low power state and becomes fully operational.
[0019] The implementation of the present invention takes advantage of existing apparatus for changing power states of a virtual machine platform 20 . The BIOS 22 provides industry standard Advanced Configuration and Power Interface (ACPI) states that are able to remove power from different parts of the platform 20 .
[0020] In the implementation of the invention, there is a path through network 10 (may be the Internet or Web) via connection 11 through ASIC (Application-Specific Integrated Circuit) compression core 12 wherein the user desktop 1 - n computers may be respectively connected to their allocated VM 1 - n and operating system OS 1 - n . This is controlled by hypervisor 21 . The ASIC compression core enables data from the user computers, desktops 1 - n , to be suitably compressed so as to be most efficiently stored in association with the virtual machine platform for usage by the virtual machines to which the data is illustrated to be applied via connections 13 , 14 and 15 . Standard ASIC cores are described in the publication: Data compression technology in ASIC cores, S. H. Burroughs et al., in the IBM Journal of Research and Development, Volume 42, Number 6, 1998.
[0021] The tailoring of the ASIC core has sufficient flexibility so that a connection 16 may be formed from ASIC Compression Core 12 through the Baseboard Management Controller (BMC) 17 in the platform 20 directly into BIOS 22 . BMC is a conventional specialized mini-controller embedded in a conventional server computer baseboard that functions as the intelligence using the conventional Intelligent Platform Management Interface (IPMI). The BMC, thus, functions to manage the interface between the system management software and the platform hardware.
[0022] As will be hereinafter described in greater detail with respect to the program of this invention, which may be stored in the hypervisor 21 , the BMC 17 tracks the number of users in the environment of the virtual machine platform 20 . When a session between a client device (user desktop) and its allocated VM is tracked to have been non-active for a predetermined period, the BMC removes the user computer from the activity pool. Each entry and exit from the non-activity state is logged for each client device or user computer. In an embodiment to be described with respect to FIG. 4 , use is made of an embedded activity timer proved in standard ASIC cores. The BMC sets a timer when activity for a particular user computer stops. Then, upon time expiration the non-active user computer is removed from an activity tracking table located in the BMC through input to the BIOS 22 . With this implementation, the tracking and communication of the active and non-active states of the user computers or client devices is carried out independent of the operating systems and hypervisor of the virtual machine platform, allowing independent control of the low power states for the virtual machine platform.
[0023] Now, with reference to FIG. 2 , there will be shown the implementation for power management as applied in a system that has multiple virtual machine platforms (A-N) respectively connected to a plurality of sets of user computers (client devices). Such an arrangement is utilized in virtual machine environments used for virtual server farms. In such an arrangement, each Platform A-N may each function independently in the manner described for the virtual machine platform of FIG. 1 . For convenience in illustration, elements 111 through 117 and 120 through 122 in Platform N correspond to and function in the same manner as described above for elements 11 through 17 and 20 through 22 in Platform A.
[0024] FIG. 3 is a flowchart showing the development of a process according to the present invention for power management in a virtual machine environment. In a multi-virtual machine platform environment, an implementation is provided wherein each virtual machine platform has a plurality of virtual machines, each of which is adapted to be connected to one of a plurality of user computers (client devices), step 71 . Provision is made to connect the user computers of step 71 to a virtual machine via a network, step 72 . Provision is made for monitoring (independently of any connection in step 71 ) whether each of the plurality of computers is in the active state, step 73 . Provision is made for determining if all of the plurality of connected computers are in the non-active state, step 74 . Provision is made for the switching of the virtual machine platform into a reduced power consumption state responsive to a determination in step 74 that all of the connected computers are in the non-active state, step 75 . Provision is made for controlling the switching of step 75 within the virtual machine platform wherein communication as to whether the connected computers are in a non-active state is by a path independent of the operating system of the virtual machine platform, step 76 . Provision is made for communicating the non-active states determined in step 76 directly to the BIOS of the virtual machine platform, step 77 .
[0025] The running of the process set up in FIG. 3 is described with respect to the flowchart of FIG. 4 . Initially, step 81 , the system has been powered on. Accordingly, there are remote user computers (client devices) connected, step 82 . A counter is set (step 83 ):
[0000] Users Active=Remote users+1
[0000] A determination is then made, step 84 , as to whether there has been a change in remote user computer activity, step 84 . If Yes, then, step 85 , a determination is made as to whether there has been an interrupt (or change) in the activity of a remote user, step 85 . In this step, a user can connect, disconnect or become inactive (if the user's activity timer has expired). If Yes, there has been a user activity interrupt, the remote user has disconnected from the active state, step 86 . Then the counter is changed (step 87 ):
[0000] Users active=users active−1
[0000] A determination is then made (step 88 ):
[0000] Active users=0, step 88
[0000] If No, the flow is branched back to step 84 and the process continued. If Yes, step 89 , there is a BIOS/ACIP interrupt in the virtual machine platform to allow the system into a low power “S 3 Sleep” state. The BIOS then advises the hypervisor for the platform to save the contexts, step 90 . In this low power consumption sleep state, the activity of the remote user computers continues to be monitored, step 90 , for a change back to a remote user activity state. If Yes, then step 91 , there is a BIOS/ACIP change in the virtual machine platform into a high activity power-on “S 5 ” full power state. The BIOS then advises the hypervisor for the platform to restore the contexts, step 92 .
[0026] Although certain preferred embodiments have been shown and described, it will be understood that many changes and modifications may be made therein without departing from the scope and intent of the appended claims. | Power management in a virtual machine environment that includes at least one virtual machine platform providing a plurality of virtual machines, and a plurality of separate (user) computers, each connected to a respective one of the virtual machines in a typical virtual machine distribution environment. There is also provided a function, independent of the connections of the user computers to the virtual machines, for determining if each of said computers connected to the virtual machines is in an active state together with a function for switching the virtual machine platform into a reduced power consumption state in the platform when all of the computers connected to virtual machines are in a non-active state. | 6 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to invasive medical devices. More particularly, this invention relates to ablation of tissue using such devices.
[0003] 2. Description of the Related Art
[0004] Ablation of body tissue using electrical energy is known in the art. The ablation is typically performed by applying alternating currents, for example radiofrequency energy, to the electrodes, at a sufficient power to destroy target tissue. Typically, the electrodes are mounted on the distal tip of a catheter, which is inserted into a subject. The distal tip may be tracked in a number of different ways known in the art, for example by measuring magnetic fields generated at the distal tip by coils external to the subject.
[0005] A known difficulty in the use of radiofrequency energy for cardiac tissue ablation is controlling local heating of tissue. There are tradeoffs between the desire to create a sufficiently large lesion to effectively ablate an abnormal tissue focus, or block an aberrant conduction pattern, and the undesirable effects of excessive local heating. If the radiofrequency device creates too small a lesion, then the medical procedure could be less effective, or could require too much time. On the other hand, if tissues are heated excessively then there could be local charring effects, coagulum, and or explosive steam pops due to overheating. Such overheated areas can develop high impedance, and may form a functional barrier to the passage of heat. The use of slower heating provides better control of the ablation, but unduly prolongs the procedure.
[0006] U.S. Pat. No. 8,147,484 to Lieber et al. discloses real-time optical measurements of tissue reflection spectral characteristics while performing ablation. The technique involves the radiation of tissue and recapturing of light from the tissue to monitor changes in the reflected optical intensity as an indicator of steam formation in the tissue for prevention of steam pop. Observation is made to determine whether measured reflectance spectral intensity (MRSI) increases during a specified time period followed by a decrease at a specified rate in the MRSI. If there is a decrease in the MRSI within a specified time and at a specified rate, then formation of a steam pocket is inferred.
SUMMARY OF THE INVENTION
[0007] Commonly assigned U.S. Provisional Application No. 61/984953, which is herein incorporated by reference, discloses that optical reflectivity measured by optical sensors near the tip of a catheter indicate events, such as imminent occurrence of steam pops.
[0008] According to disclosed embodiments of the invention, the depth of an ablation lesion is assessed using a differential optical response of a catheter with multiple fiberoptic transmitters and receivers at the tip. To detect tissue optical response at shallow depths, closely-spaced transmitter/receiver pairs are used. To detect deeper tissue response, the same transmitter can be used with another receiver that is farther away (or vice versa). The distance between the transmitter and receiver is chosen depending on the desired depth of sensing. Plateauing or peaking of the optical signal during the course of ablation indicates an end point at a selected tissue depth.
[0009] There is provided according to embodiments of the invention an insertion tube configured for insertion into proximity with tissue in a body of a patient. The tube has an electrical conductor for delivering energy to the tissue and a conductive cap attached to the distal portion of the insertion tube and coupled electrically to the electrical conductor. A plurality of optical fibers contained within the insertion tube have terminations at the distal portion. The optical fibers are configurable as optical transmitting fibers to convey optical radiation to the tissue and as optical receiving fibers to convey reflected optical radiation from the tissue. At the distal portion of the insertion tube, the terminations of the optical fibers are spaced apart at respective distances from one another. An optical module is configured to interrogate the tissue at a predetermined depth by selectively associating the optical transmitting fibers with the optical receiving fibers according to the respective distances therebetween, the optical module being operative to emit light along a light path that passes through a selected optical transmitting fiber, reflects from the tissue, and returns to the optical module as reflected light via a selected optical receiving fiber while the electrical conductor is delivering energy to the tissue. A processor linked to the optical module analyzes the reflected light.
[0010] According to another aspect of the apparatus, the optical module is operative for varying an intensity of the light that is emitted in the light path.
[0011] According to still another aspect of the apparatus, the emitted light in the light path is monochromatic.
[0012] According to an additional aspect of the apparatus, the emitted light in the light path has a wavelength of 675 nm.
[0013] According to another aspect of the apparatus, the selectively associated optical transmitting fibers and optical receiving fibers are spaced apart by intervals of 0.5-2 mm.
[0014] According to one aspect of the apparatus, analyzing the reflected light includes determining a time at which the reflected light ceases to vary in intensity by more than a predetermined rate.
[0015] According to a further aspect of the apparatus, analyzing the reflected light includes identifying a time of a peak in intensity in the returning light.
[0016] According to still another aspect of the apparatus, analyzing the reflected light includes determining at respective depths of interrogation times at which variations in a rate of change of a reflected light intensity by more than a predetermined percentage occur.
[0017] According to an additional aspect of the apparatus, analyzing the reflected light includes calculating a ratio of two wavelengths and determining a time at which the ratio ceases to vary by more than a predetermined rate.
[0018] There is further provided according to embodiments of the invention a method, which is carried out by configuring optical fibers contained within a probe as optical transmitting fibers and as optical receiving fibers, wherein terminations of the optical fibers are spaced apart at respective distances from one another, inserting the probe into a body of a patient. While delivering energy to a tissue in the body through an ablator of the probe, the method is further carried out by interrogating the tissue at a predetermined depth by selectively associating one of the optical transmitting fibers with one of the optical receiving fibers according to the respective distances therebetween, and establishing a light path extending from a light emitter through the one optical transmitting fiber to reflect from the tissue and continuing as reflected light from the tissue through the one optical receiving fiber to a receiver. The method is further carried out by transmitting light from the light emitter along the light path, and analyzing the reflected light reaching the receiver via the one optical receiving fiber.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0019] For a better understanding of the present invention, reference is made to the detailed description of the invention, by way of example, which is to be read in conjunction with the following drawings, wherein like elements are given like reference numerals, and wherein:
[0020] FIG. 1 is a pictorial illustration of a system for performing ablative procedures, which is constructed and operative in accordance with a disclosed embodiment of the invention;
[0021] FIG. 2 is a schematic, perspective illustration of a catheter cap in accordance with an embodiment of the invention;
[0022] FIG. 3 is an isometric view of the distal end of a catheter in accordance with an alternate embodiment of the invention;
[0023] FIG. 4 is a schematic side view taken along line 5 - 5 of FIG. 4 , in accordance with an embodiment of the invention;
[0024] FIG. 5 schematically illustrates paths taken by light to/from windows in the cap shown in FIG. 2 , in accordance with an embodiment of the invention;
[0025] FIG. 6 is a schematic view of the distal end of a catheter, in accordance with an embodiment of the invention;
[0026] FIG. 7 is a plot that relates the inter-element distance of an optical receiver-transmitter pair in a catheter to the elapsed time at which an ablation endpoint is observed, in accordance with an embodiment of the invention; and
[0027] FIG. 8 is a series of plots showing the effect of varying the intensity of optical radiation, in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0028] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the various principles of the present invention. It will be apparent to one skilled in the art, however, that not all these details are necessarily needed for practicing the present invention. In this instance, well-known circuits, control logic, and the details of computer program instructions for conventional algorithms and processes have not been shown in detail in order not to obscure the general concepts unnecessarily.
Overview
[0029] Turning now to the drawings, reference is initially made to FIG. 1 , which is a pictorial illustration of a system 10 for evaluating electrical activity and performing ablative procedures on a heart 12 of a living subject, which is constructed and operative in accordance with a disclosed embodiment of the invention. The system comprises a catheter 14 , which is percutaneously inserted by an operator 16 through the patient's vascular system into a chamber or vascular structure of the heart 12 . The operator 16 , who is typically a physician, brings the catheter's distal tip 18 into contact with the heart wall, for example, at an ablation target site. Electrical activation maps may be prepared, according to the methods disclosed in U.S. Pat. Nos. 6,226,542, and 6,301,496, and in commonly assigned U.S. Pat. No. 6,892,091, whose disclosures are herein incorporated by reference. One commercial product embodying elements of the system 10 is available as the CARTO® 3 System, available from Biosense Webster, Inc., 3333 Diamond Canyon Road, Diamond Bar, Calif. 91765. This system may be modified by those skilled in the art to embody the principles of the invention described herein.
[0030] Areas determined to be abnormal, for example by evaluation of the electrical activation maps, can be ablated by application of thermal energy, e.g., by passage of radiofrequency electrical current through wires in the catheter to one or more electrodes at the distal tip 18 , which apply the radiofrequency energy to the myocardium. The energy is absorbed in the tissue, heating it to a point (typically above 50° C.) at which it permanently loses its electrical excitability. When successful, this procedure creates non-conducting lesions in the cardiac tissue, which disrupt the abnormal electrical pathway causing the arrhythmia. The principles of the invention can be applied to different heart chambers to diagnose and treat many different cardiac arrhythmias.
[0031] The catheter 14 typically comprises a handle 20 , having suitable controls on the handle to enable the operator 16 to steer, position and orient the distal end of the catheter as desired for the ablation. To aid the operator 16 , the distal portion of the catheter 14 contains position sensors (not shown) that provide signals to a processor 22 , located in a console 24 . The processor 22 may fulfill several processing functions as described below.
[0032] Ablation energy and electrical signals can be conveyed to and from the heart 12 through one or more ablation electrodes 32 located at or near the distal tip 18 via cable 34 to the console 24 . Pacing signals and other control signals may be conveyed from the console 24 through the cable 34 and the electrodes 32 to the heart 12 . Sensing electrodes 33 , also connected to the console 24 are disposed between the ablation electrodes 32 and have connections to the cable 34 .
[0033] Wire connections 35 link the console 24 with body surface electrodes 30 and other components of a positioning sub-system for measuring location and orientation coordinates of the catheter 14 . The processor 22 or another processor (not shown) may be an element of the positioning subsystem. The electrodes 32 and the body surface electrodes 30 may be used to measure tissue impedance at the ablation site as taught in U.S. Pat. No. 7,536,218, issued to Govari et al., which is herein incorporated by reference. A temperature sensor (not shown), typically a thermocouple or thermistor, may be mounted on or near each of the electrodes 32 .
[0034] The console 24 typically contains one or more ablation power generators 25 . The catheter 14 may be adapted to conduct ablative energy to the heart using any known ablation technique, e.g., radiofrequency energy, ultra-sound energy, and laser-produced light energy. Such methods are disclosed in commonly assigned U.S. Pat. Nos. 6,814,733, 6,997,924, and 7,156,816, which are herein incorporated by reference.
[0035] In one embodiment, the positioning subsystem comprises a magnetic position tracking arrangement that determines the position and orientation of the catheter 14 by generating magnetic fields in a predefined working volume and sensing these fields at the catheter, using field generating coils 28 . The positioning subsystem is described in U.S. Pat. No. 7,756,576, which is hereby incorporated by reference, and in the above-noted U.S. Pat. No. 7,536,218.
[0036] As noted above, the catheter 14 is coupled to the console 24 , which enables the operator 16 to observe and regulate the functions of the catheter 14 . Console 24 includes a processor, preferably a computer with appropriate signal processing circuits. The processor is coupled to drive a monitor 29 . The signal processing circuits typically receive, amplify, filter and digitize signals from the catheter 14 , including signals generated by sensors such as electrical, temperature and contact force sensors, and a plurality of location sensing electrodes (not shown) located distally in the catheter 14 . The digitized signals are received and used by the console 24 and the positioning system to compute the position and orientation of the catheter 14 , and to analyze the electrical signals from the electrodes.
[0037] In order to generate electroanatomic maps, the processor 22 typically comprises an electroanatomic map generator, an image registration program, an image or data analysis program and a graphical user interface configured to present graphical information on the monitor 29 .
[0038] An optical module 40 provides optical radiation, typically from, but not limited to, a laser, an incandescent lamp, an arc lamp, or a light emitting diode (LED), for transmission from distal tip 18 to the target tissue. The module receives and cooperatively with the processor 22 analyzes optical radiation returning from the target tissue and acquired at the distal end, as described below.
[0039] Typically, the system 10 includes other elements, which are not shown in the figures for the sake of simplicity. For example, the system 10 may include an electrocardiogram (ECG) monitor, coupled to receive signals from one or more body surface electrodes, in order to provide an ECG synchronization signal to the console 24 . As mentioned above, the system 10 typically also includes a reference position sensor, either on an externally-applied reference patch attached to the exterior of the subject's body, or on an internally-placed catheter, which is inserted into the heart 12 maintained in a fixed position relative to the heart 12 . Conventional pumps and lines for circulating liquids through the catheter 14 for cooling the ablation site are provided. The system 10 may receive image data from an external imaging modality, such as an MRI unit or the like and includes image processors that can be incorporated in or invoked by the processor 22 for generating and displaying images.
[0040] Reference is now made to FIG. 2 , which is a schematic, perspective illustration of a catheter cap 100 , in accordance with an embodiment of the invention. Cap 100 comprises a side wall 74 that is on the order of 0.4 mm thick, in order to provide the desired thermal insulation between optional temperature sensors 48 and the irrigation fluid inside a central cavity 76 of the tip. Irrigation fluid exits cavity 76 through apertures 46 .
[0041] Reference is now made to FIG. 3 , which is an isometric view of the distal end of a cap 113 for a catheter in accordance with an alternate embodiment of the invention. In this embodiment six openings 114 are located at distal end 115 . As explained below the opening 114 constitute windows at the terminations of fiberoptic elements that extend longitudinally through the catheter 14 into the cap 113 . In other embodiments, the cap 113 may be provided with other windows (not shown) to accommodate sensors, e.g., temperature or contact force sensors.
[0042] Reference is now made to FIG. 4 , which is a schematic side view showing the interior of the cap 100 ( FIG. 2 ), in accordance with an embodiment of the invention. Three through longitudinal bores 102 and three blind longitudinal bores 72 are formed in side wall 74 . The three sets of bores 72 , 102 may be distributed symmetrically around a longitudinal axis of cap 100 . However, the bores are not necessarily distributed symmetrically around the axis. Optional sensors 48 are mounted in hollow tubes 78 , which are filled with a suitable glue, such as epoxy and fitted into longitudinal bores 72 in side wall 74 . Tubes 78 may comprise a suitable plastic material, such as polyimide, and may be held in place by a suitable glue, such as epoxy. This arrangement provides an array of sensors 48 , with possible advantages of greater ease of manufacture and durability.
[0043] Each through longitudinal bore 102 terminates in an opening 114 in the surface of wall 74 , and a transparent window 116 is placed in the opening. A fiber optic 118 is inserted into each of the through bores. In some embodiments, temperature sensors 48 may not be installed, and only fiber optics 118 are incorporated into the wall. Such an embodiment enables determination of tissue contact with the cap, and/or characterization of the tissue in proximity to the cap, by methods described below.
[0044] Window 116 acts as a seal preventing fluid external to the outer surface of cap 100 from penetrating into the bores containing the fiber optics. Window 116 may be formed by filling opening 114 with an optically transparent glue or epoxy. In some embodiments, the material of the windows may be filled with a scattering agent to diffuse light passing through the windows.
[0045] Alternatively, the windows may be formed from an optical quality flat or lensed material, and may be secured to their openings with glue.
[0046] In one embodiment, each fiber optic 118 or each fiber optic 128 is a single fiber optic, typically having a diameter of approximately 175 μm. In an alternative embodiment each fiber optic 118 or each fiber optic 128 comprises a bundle of substantially similar fiber optics, typically having a bundle diameter also of approximately 175 μm. Implementing the fiber optics as bundles increases the flexibility of cap 100 with respect to more proximal regions of the catheter 14 ( FIG. 1 ).
[0047] Such an increase in flexibility is advantageous if cap 100 is connected to the more proximal regions of the catheter by a spring whose deflections are measured for the purpose of measuring a force on the cap, since the increased flexibility means there is little or no change in the spring deflection for a given force. A spring that may be used to join the cap 100 to the more proximal regions of the catheter is described in U.S. Patent Application Publication No. 2011/0130648 by Beeckler et al., whose disclosure is incorporated herein by reference.
[0048] Optical module 40 ( FIG. 1 ) is configured to be able to provide optical radiation to any one of fiber optics 118 and 128 , for transmission from any of the associated windows 116 , 124 in order to irradiate tissue in proximity to cap 100 . Simultaneously, the optical module 40 is able to acquire, via any or all of the windows, radiation returning from the irradiated tissue.
[0049] The array of windows 116 , 124 , and their associated fiber optics, enables embodiments of the present invention to employ a number of different methods, using optical radiation, for determining characteristics of the irradiated tissue, as well as the proximity of cap 100 , or a region of the cap, with respect to the tissue. By way of example, three such methods are described below, but those having ordinary skill in the art will be aware of other methods, and all such methods are included within the scope of the present invention.
[0050] A first method detects contact of any one of windows 116 , 124 , and consequently of the catheter, with tissue. Optical radiation, of a known intensity, is transmitted through each fiber optic, to exit from the optic's window. The intensity of the radiation returning to the window is measured while cap 100 is not in contact with tissue, typically while the cap is in the blood of heart 12 ( FIG. 1 ). Optical module 40 may use these intensities as reference values of the optical radiation.
[0051] For any given window, a change in the value from the window's reference value, as measured by the module, may be taken to indicate that the window is in contact with tissue.
[0052] A second method measures characteristics of tissue being irradiated by the optical radiation. Reference is now made to FIG. 6 , which schematically illustrates paths taken by light to/from windows in the cap 100 ( FIG. 2 ), in accordance with an embodiment of the invention.
[0053] As illustrated in FIG. 5 , for all six windows 116 , 124 there are a total of 21 different paths, comprising 6 paths 150 where radiation from a given window returns to that window, and 15 paths 160 where radiation from a given window returns to a different window. The change of optical radiation for a given path or group of paths depends on characteristics of tissue in the path or group of paths, so that measurements of the change in all of the paths provide information related to characteristics of the tissue in proximity to cap 100 .
[0054] For example, the change in all of the paths may be measured by sequentially transmitting, in a time multiplexed manner, optical radiation from each of the windows 116 , 124 , and measuring the returning radiation. A first transmission from a first window in such a sequence provides values for five paths 160 plus a return path 150 to the first window. A second transmission from a second window provides values for four new paths 160 plus return path 150 to the second window. A third transmission from a third window provides values for three new paths 160 plus return path 150 to the third window. A fourth transmission from a fourth window provides values for two new paths 160 plus return path 150 to the fourth window. A fifth transmission from a fifth window provides values for one new path 160 to the sixth window, and return path 150 to the fifth window). A sixth and final transmission from a sixth window provides one return path 150 through the sixth window.
[0055] Optical module 40 ( FIG. 1 ) enables a first portion of the fibers as optical transmitting fibers and a second portion of the fibers as optical receiving fibers. The optical module 40 selectively associates the optical transmitting fibers with the optical receiving fibers to produce a light path passing through a selected optical transmitting fiber, reflecting from the target tissue, and returning via a selected optical receiving fiber. As the first portion and the second portion of the fibers are spaced apart at respective distances, by appropriate choice of an optical transmitting fiber and an optical receiving fiber, the optical module 40 is able to interrogate the target tissue at a desired depth according to inter-element spacing between the optical transmitting fiber and the optical receiving fiber. The optical module 40 cooperatively with the processor 22 ( FIG. 1 ) may measure the changes of all the paths, and, using a calibration procedure, may derive from the changes optical characteristics of tissue within the paths. Such characteristics may include an overall level of ablation of tissue, or an amount and/or type of necrotic tissue, in the paths.
[0056] The light in the light path may be monochromatic light, for example at a wavelength of 675 nm. Alternatively, the light may have broader spectrum.
[0057] Reference is now made to FIG. 6 , which is a schematic view of the distal end of a catheter, in accordance with an embodiment of the invention. Nine terminations of fiberoptic elements (O, A-H) are shown. Chords OA-OH connect element O with elements A-H, respectively. The accompanying table indicates the corresponding inter-element distances of the terminations. While FIG. 7 exhaustively depicts light paths in respect of element O, in practice not all of the positions need be dedicated to fiberoptic elements. In a current embodiment, three positions (elements H, B, and E) are assigned to temperature sensors, thereby leaving fewer light paths to be selected,
Operation
[0058] Continuing to refer to FIG. 6 , the catheter is operated in cooperation with the system 10 ( FIG. 1 ) by configuring an element, e.g., element O, as one member of an optical receiver-transmitter pair and another element, e.g., elements A-H as the other member. The selected receiver-transmitter pair is optimum for interrogating the ablation site at a respective depth. For example, an inter-element distance of 0.5 mm is optimum for a shallow depth of interrogation. An inter-element distance of about 2 mm is optimum for a deeper level of approximately 2-3 mm. The selected inter-element distance may be varied, either by holding one element, e.g., element O, fixed, and analyzing the other elements in turn, or by changing the pairing according to a predetermined schedule. In any case, the reflectances measured by the pairs are analyzed as the ablation proceeds. Once the signal is received using the largest inter-element distance stabilizes (or peaks), it may be concluded that no further changes are occurring in the tissue at that level. Although the optical interrogation depth is approximately 2-3 mm, the total depth of the lesion can be extrapolated based upon the magnitude of change at the maximum interrogation depth. Alternatively, by operating a plurality of the elements as optical transmitters at respective wavelengths, multiple receiver-transmitter pairs may be operated concurrently.
Results
[0059] Reference is now made to FIG. 7 , which is a plot that relates the inter-element distance of optical receiver-transmitter pairs in a catheter to the elapsed time at which a change in optical intensity is observed, in accordance with an embodiment of the invention. In a medical procedure of this sort, the depth of ablation increases with elapsed time. A correlation is shown between the interrogation depth at a particular distance and the elapsed time, indicating that optical reflectances at increasing receiver-transmitter pair distances are useful for detecting increasing ablation depths.
[0060] Reference is now made to FIG. 8 , which is a series of plots showing the effect of varying the intensity of optical radiation, in accordance with an embodiment of the invention. An endpoint may be determined by establishing a time at which the intensity of the reflected light fails to vary by more than a predetermined rate. Alternatively, the endpoint may be determined by identification of a peak in the intensity of the reflected light endpoints 162 , 162 , 164 , 166 .
[0061] Alternatively, the endpoint may be determined by transmitting light through a path via the fiberoptic elements at two wavelengths and calculating a ratio of the reflected light at the two wavelengths. The endpoint may be defined as a time at which the ratio ceases to vary by more than a predetermined rate.
[0062] Analysis of reflectance data may comprise identification of a point (referred to herein as a “startpoint”). As the interrogation depth increases, startpoints represents times at which variations in the rate of change of reflectance by more than a predetermined percentage occur. Such startpoints correspond respectively to different interrogation depths. The first startpoints occur at shallow interrogation depths and the later instances occur at deeper interrogation depths.
[0063] The lowermost plot was obtained using the highest separation distance, and exhibits a distinct peak, whereas lower separation distances result in a flattening or plateau after an endpoint of the ablation is reached as shown by points 162 , 164 , 166 , 168 .
[0064] It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description. | The depth of an ablation lesion is assessed using a differential optical response of a catheter with multiple fiberoptic transmitters and receivers at the tip. To detect tissue optical response at shallow depths, closely-spaced transmitter/receiver pairs of optical fibers are used. To detect deeper tissue response, the same or a different transmitter can be used with another receiver that is relatively farther away. The distance between the transmitter and receiver is chosen depending on the desired depth of sensing. Plateauing or peaking of the optical signal during the course of ablation indicates an end point at a selected tissue depth. | 0 |
This application is a continuation of application Ser. No. 697,891, filed June 21, 1976, now abandoned, which is a continuation of application Ser. No. 528,177, filed Nov. 29, 1974, now abandoned.
CROSS-REFERENCE TO RELATED APPLICATION
U.S. patent application No. 293,956 to Ralph L. Vick filed Oct. 2, 1972, now abandoned.
BACKGROUND OF THE INVENTION
In many flow control applications there is a need for structures which can vary the fluid-flow rate of flowing fluids without the production of excessive wear, noise or vibration. The term "throttling" is generally applied to the function of altering or adjusting fluid flow throughout a range of flow rates. The various structures by which the function is performed are generally called "throttling valves" to distinguish them from structures whose function is to open and close a flow path as a step function. To the extent that on-off valves are not opened and closed instantaneously so that throttling noise and vibration may be produced therein at the time of opening or closure, the invention described herein is applicable to such valves as well, and they are included in the term "throttling valve".
A typical control valve for handling the flowing of high pressure fluids employs a structure in which the cross-sectional area of the flow path is altered. This type of structure generally produces substantial noise and vibration and is quite subject to damage from cavitation. However, the structures employed in this arrangement are, as a class, least expensive and most conveniently employed. The conventional spool-type hydraulic servo valve is typical of this type of valve.
Hydraulic systems of commercial aircraft usually employ phosphate-ester-based hydraulic fluids because of their fire-resistant properties. These fluids, however, have been found to be extremely erosive in the throttling or metering control valves of these systems. In effect, they induce an electrochemical milling action on the valve metering edges which is quite apart from the normal wear associated with fluid flow. Improvements have been made in the fluids, and various attempts at valve design changes have effected some gains; however, the problem remains a severe one with valves surviving from only a very few hours to an acceptable life, but still far below that of valves that work in most other fluid systems. The phenomena is characteristic of other fluids; however, the severity with which it occurs it hydraulic systems using phosphate-ester-based fluids is particularly unique.
In systems using phosphate-ester-based fluids, one of the most erosive conditions extant can be found on valves which are rigged or used in a nearly closed condition for long periods of time, or valves which are underlapped (or have zero lap) and remain at null or near null for long periods of time. The configurations involved include flight control system valves, spoiler control system valves, flap control valves (which are modulating types), relief valves that have continuous low leakage or erode to that condition, and other valves that are high differential pressure-throttling configurations with continuous "built-in" or "eroded to" flow conditions. Once flow is established and the "electrochemical milling" begins, the erosion is usually continuous until the leakage rate of the valve is no longer tolerable.
There have been many structures devised in an attempt to deal with the damage resulting from operation of valves in high pressure systems. Most of these have involved some form of baffling means which operate in one way or another to divide the flow and cause the pressure drops to be taken at various locations rather than across a single metering edge. One such arrangement is described in the copending application of applicant, referred to above, in which flow is divided into many fine streams by a series of stacked disks surrounding a spool valve and in which each small stream is caused to flow into a chamber, from thence across an orifice to another chamber, reversing direction through another orifice, etc., radially across the disks. In this arrangement the pressure drops across the disks are essentially those caused by the orifices in series. One problem which has been experienced with this arrangement is that the disks containing the orifices are not configured to receive or discharge fluid, nor are the blank disks. Thus, particularly where a spool valve has very small travel, the thickness of these "dead" disks creates an irregularity in flow which it is preferable to avoid. Even where some of the orifice disks or blank disks are configured to admit fluid into the stack, the flow pattern may be unacceptably rough because each increment of flow, as defined by openings of each disk width, effectively saturates before a new increment begins.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a typical spool-type servo valve using my invention;
FIG. 2 is a plan view of one type of disk used in FIG. 1;
FIG. 3 is a plan view of a second type of disk used in FIG. 1;
FIG. 4 is a plan view of a third type of disk used in FIG. 1;
FIG. 5 is a plan view of a disk similar to that of FIG. 4 but reversed;
FIG. 6 is a plan view of a fourth type of disk used in FIG. 1;
FIG. 7 is a plan view of a disk similar to that of FIG. 2, but reversed and radially displaced;
FIG. 8 is a graph showing a flow vs. displacement characteristic of a prior art type of valve structure;
FIG. 9 is a graph showing the relationship of flow vs. displacement of a valve such as that described in connection with FIGS. 1-7.
FIGS. 10-14 represent a second embodiment of my invention involving a second set or stack of disks in which:
FIG. 10 is a plan view of a first disk which may be used in the valve of FIG. 1;
FIG. 11 is a plan view of a second disk which may be used in the valve of FIG. 1;
FIG. 12 is a plan view of a third disk which may be used in the valve of FIG. 1;
FIG. 13 is a plan view of a fourth disk which may be used in the valve of FIG. 1;
FIG. 14 is a plan view of a fifth disk which may be used in the valve of FIG. 1; and
FIG. 15 is a graph showing the relationship of flow vs. displacement of a valve such as that of FIG. 1 wherein the disks of FIGS. 10-14 are used.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A flow control valve is shown generally at numeral 10 whose purpose is to control flow to an external utilization device such as a cylinder. Fluid from a source, not shown, is applied to an inlet passage 12, and flow from the valve member 10 is provided to an actuating cylinder 13 through outlet conduits 14 and 16 connected to opposite sides of a piston 15. Positioned within valve 10 is a generally cylindrical chamber 18 having a plurality of different diameters. The stationary sleeve member 20, having a plurality of matching diameters, is positioned in chamber 18. Axially movable within the sleeve 20 is a spool valve 22 which is directly driven mechanically by means of a rotatable control member 24 having an extendible arm 26 engaging the spool member 22.
Fluid flow entering inlet passage 12 passes a conventional check valve 28 and flows through an orifice or series of orifices 30 which are radially positioned through the side wall of sleeve member 20 to provide communication to a chamber 32. Defining the ends of chamber 32 are a pair of lands 34 and 36 movable axially with spool valve member 22 in such manner as to direct high pressure inlet fluid from chamber 32 into either of cylinder passages 14 or 16. When spool member 22 has moved toward the left, land 34 is similarly displaced, thus opening communication between chamber 32 and passage 14. At the same time, land 36 also moves to the left, opening communication between passage 16 and a chamber 38 which communicates with return pressure through a line 40. This results in movement of piston 15 toward the right. Movement of the spool 22 in the opposite direction results in connecting high pressure fluid from chamber 32 to line 16 and permitting fluid on the left side of the cylinder 15 to be exhausted through passageway 14 into a chamber 42 which communicates with return conduit 40 through a line 44, a chamber 46 and a passageway 48, and causing piston 15 to be moved toward the left.
Surrounding each of lands 34 and 36 are stacks of disks 50 and 52, respectively, which are stacked in a face-to-face relationship and which include patterns of openings and orifices which divide the flow into a number of flow paths for minimizing wear, noise and/or erosion damage to the valve which might otherwise result because of the high pressure differentials employed. It will be observed that with the particular valve configuration shown, flow may be directed across the disks either from inside to outside or from outside to inside, depending upon which set of disks is considered and which direction the spool 22 is moved. Because of the smaller effective area on the internal diameter, it is frequently important in this type of valve that the flow versus displacement relationship be reasonably smooth and that abrupt changes do not occur as the spool is moved across one disk element and then another.
The configuration of the individual disks shown in stacks 50 and 52 will become apparent from consideration of the following figures. FIG. 2 shows a disk 60 having a pattern of openings across certain radial lines. Radial orientation of these openings from disk to disk is important in understanding the various flow paths. In the particular embodiment described in FIGS. 2 through 7, openings are arranged along ten equally spaced radii, meaning that a pattern of openings will occur at some point in the stack every 36°. The number of such openings and the number and arrangement of pressure drop orifices across the stack will be defined by the requirements of a particular installation. In order to provide reasonably smooth flow vs. displacement characteristics, the pattern of openings on the inside circumference of the disks will preferably be such as to provide the flow patterns into the stack at each disk position. In disk 60, openings 62 are shown on the inside circumference along a vertical line and along the same line are interior openings 64 and openings 66 at the outside circumference. Displaced 36° counterclockwise from the vertical are sets of interior openings 68. The next disk 70 shown in FIG. 3, which it will be understood is positioned adjacent disc 60, has a corresponding set of openings 72, 74 and 76 along a vertical line. It also has a set of interior openings 78 which correspond exactly with openings 68 in disk 60. In addition disk 70 has, along radii displaced an additional 36° counterclockwise from opening 78, a series of openings including openings 80 leading into the stack from the internal circumference, an internal opening 84 and openings 82 communicating with the outside circumference of the disk. Displaced a further 36° counterclockwise are a series of internal openings 86. Since disks 60 and 70 are preferably of the order of 0.004 or 0.005 inches thick, it will be recognized that openings 62 and 72 in cooperation constitute an opening into the stack of 0.008 to 0.010 inch in width. In general, it is preferred that the width of these passageways not be much less than this, since narrower openings are much more subject to blocking from contamination.
Referring now to FIG. 4, it will be observed that the pattern of openings in this figure is quite different from that of FIGS. 2 and 3. While appearing as a pair of partial disks, this disk is actually formed as a unit and is shown as it would appear after all trimming has been accomplished. The disks are initially formed with both larger outside diameters and smaller inside diameters. Disk 90 has a pattern of openings including openings into the stack 92, an intermediate opening 94 and an opening into the exterior circumference 96 which correspond exactly with openings 80, 82 and 84 in disk 70. There is also a pattern of internal openings 98 which register with openings 86 in disk 70. Displaced an additional approximately 36° counterclockwise from openings 98 are openings 100 which communicate with large slots 102. Also present in disk 90 are a series of small orifices 104 which register directly with the vertically arranged openings 62, 64 and 66 in disk 60 and openings 72, 74 and 76 in disk 70 and also in a position displaced 36° counterclockwise from the openings 104 is a set of orifices 106 which register with openings 68 and 78 in disks 60 and 70, respectively. In FIG. 5 is shown an additional disk 110 which will be stacked adjacent disk 90 of FIG. 4 and which includes a large opening 112 which registers exactly with openings 102 in disk 90 and which communicates with the inside circumference through ports 114. Disk 110 also includes a set of internal openings 116 along a vertical line which register with orifices 104 of disk 90. Displaced 36° clockwise from openings 114 are sets of orifices 118 which register with openings 98 of disk 90. At the next clockwise position on disk 110 are additional sets of orifices which register with openings 92, 94 and 96 of disk 90. At the next position clockwise from orifices 120 of disk 110 is a series of openings including openings 122 into the stack from the internal diameter and intermediate openings 124 and openings 126 on the outside diameter of the disk. These openings register with orifices 106 in disk 90.
In FIG. 6 is shown a disk 130 which includes a series of internal openings 132 at the vertical position which register exactly with openings 116 in disk 110. Rotated two positions counterclockwise is another set of interior openings 134 which register with orifices 120 in disk 110. Rotated one position counterclockwise from the vertically oriented openings 132 are openings 136 in the inside circumference, intermediate openings 138 and openings 140 in the outside circumference, internal openings 144 and openings 146 in the outside circumference of disk 130.
Disk 150 shown in FIG. 7 includes a set of openings 152, 154 and 156 which register exactly with openings 142, 144 and 146 in disk 130. Displaced one position clockwise from these openings are a set of internal openings 158 which register with openings 134 in disk 130.
In considering the operation of a valve such as that of FIG. 1 wherein the disk stacks 50 and 52 are in accordance with the disks shown in FIGS. 2 through 7, one must visualize a stack in which each of the disks is placed on top of the one before in the order described. Assuming such a stack at 52 with disk 60 on the left and with land 36 being slowly moved toward the right, the following flow patterns will develop. As the land 36 moves toward the right, it will progressively uncover disks 60, 70, 90, 100, 130 and 150. The resulting flow pattern is depicted in FIG. 9 (assuming 0.005 inch thick disks). Movement past disk 60 will result in opening flow into the stack through ports 62. These ports communicate directly with the inside orifice of orifice series 104 in disk 90. Flow passing through this orifice will enter a chamber defined by openings 116 and 132 in disks 110 and 130. Flow crossing this opening will then pass through the second of orifices 104, and from thence into a chamber defined by openings 64 and 74 in disks 60 and 70. This chamber communicates with the third of orifices 104 which permits flow into the outside of the chambers defined by openings 116 and 132 of disks 110 and 130, and after flowing radially across this opening the flow passes through the outside of orifices 104 into the port defined by openings 66 and 76 of disks 60 and 70. Because of the flow entrance width of disk 60 relative to the series orifice restriction, the flow reaches a low level and saturates at about 0.12 gallons per minute (illustrative only) as shown in FIG. 9, and no additional flow occurs until the land 34 moves sufficiently far to expose disk 70. As disk 70 is exposed, flow enters the opening 72 and thereby slightly augments the flow pattern just described and, in addition, flows into opening 80 where a new flow pattern is created across the orifices 120 of disk 110, the chambers defined by interior openings 134 and 158 of disks 130 and 150 and the interior openings 84 and 94 of disks 70 and 90, finally leaving the disks at openings 82 and 96 of disks 70 and 90.
A flow pattern identical to and augmenting the flow pattern previously described is shown in FIG. 9 as the second increment extending from approximately 0.005 to 0.01 of the stroke. Further movement of the land 34 past opening 100 places a large flow in parallel with the flow patterns previously described, and this results in a very steep increase in the flow rate with little additional stroke. This is shown in the portion of FIG. 9 extending from a stroke of 0.01 to approximately 0.015. Further movement of the land past disk 110 leaves this large flow in parallel with the earlier flows and also opens an additional path wherein the flow enters the stack through opening 122, crossing the inside of orifices 106 of disk 90 to a chamber defined by the inside of openings 68 and 78 of disks 60 and 70, across the second of orifices 106 into the internal chamber defined by openings 124 and 138 of disks 110 and 130, back across the third of orifices 106 into the chamber defined by the outside of openings 68 and 78, across the outside orifice 106 into the exit opening 126. The effect of this additional flow is shown by the further steepened path of the graph as it appears between approximately 0.015 and 0.02 of the stroke. Further flow in this direction tends to move the system toward saturation, even though additional openings such as those shown at numeral 142 and 152 are exposed.
Assuming now that the land 34 again completely covers the stack 50 and land 34 is then moved toward the left, it will be disk 150 which is first exposed, and the flow pattern resulting from flow into openings 152 is entirely analogous to that which results from the earlier described initial opening into opening 62 of disk 60. Again, movement sufficient to expose openings 142 and 136 of disk 130 provides the second increment shown in FIG. 9, also as previously described. Thus, it will be appreciated that the flow vs. displacement pattern is essentially the same in either direction. However, the same concept can be employed--using more disks--to provide unequal flow patterns in each direction of spool movement.
In an earlier type of stacked disk arrangement, an improvement in wear was achieved with a pattern of fewer openings into the stack; however, the large dead band shown in FIG. 8 as the stroke progressed from 0.005 inch to approximately 0.015 inch was considered to be quite unsatisfactory in terms of response of the servo valve. It is apparent, of course, that the response with the flow pattern such as that shown in FIG. 9 will be considerably better. In this version, the stroke increments over which the flow has reached or approached a saturation are, as a practical matter, so small as to be inconsequential except near maximum flow.
A second embodiment of my invention is shown in connection with the disks shown in FIGS. 10 through 14 which operate to produce the somewhat different flow vs. displacement characteristic depicted in the graph of FIG. 15. In the application for which this embodiment was designed, it was found that curtailing the flow only to the extent of approximately one disk thickness was sufficient to avoid excessive wear of the spool and sleeve of the servo valve.
Referring now to FIGS. 10 through 14, again these disks are of the thickness previously described which is 0.004 or 0.005 inch. While five such disks are shown, more may be used in an actual installation to match the stack with the width of the land. For example, in one installation with which applicant was concerned, each stack consisted of one each of the disks of FIGS. 10, 12 and 14 and two each of the disks of FIGS. 11 and 13 arranged side by side.
Assuming now that the disks shown in FIGS. 10 through 14 are arranged in a stack such as that shown at numeral 52 of FIG. 1 and that this stack is initially covered by land 36, the subsequent movement of land 36 one disk width toward the right would permit high pressure fluid in the chamber 32 to flow into the stack through a pair of openings 162 in disk 160 which communicate with orifices 166 in disk 164 (FIG. 12). Orifices 166 communicate with a chamber defined by opening 168 in disk 170 and opening 172 in disk 174. This chamber, in turn, also communicates with an orifice 176 leading to a chamber defined by orifices 178 and 180 in disks 160 and 182. This chamber also communicates with an orifice 184 in orifice plate 164 affording communication with a chamber defined by openings 186 and 188 in disks 170 and 174, respectively. The opposite end of this chamber communicates through an orifice 190 with chambers defined by openings 192 and 194 in disks 160 and 182. From thence, flow passes through an orifice 196 into the outlet passage consisting of slots 198 and 200 in disks 170 and 174, respectively.
Assuming an identical set of disks to be located in FIG. 1 at numeral 50 and these disks to b exactly covered by land 34, movement of land 34 to the left would expose disk 174 in its first 0.005 inch of travel. This would permit flow to enter into the stack through openings 202, and this flow is then immediately communicated with orifices 204 of the orifice plate 164. These orifices communicate with a chamber defined by openings 206 and 208 in disks 160 and 182, respectively. Flow crossing the chamber defined by openings 206 and 208 passes through an orifice 212 into the chambers defined by openings 214 and 216 in disks 170 and 174. This flow is, in turn, directed across the orifice 218 into a chamber defined by openings 220 and 222, from thence across orifice 224 to a chamber defined by openings 226 and 228, from thence across orifice 230 into the exit slot formed by openings 232 and 234. Thus, the flow pattern is entirely analogous to that previously described, and the flow characteristic is also that shown in FIG. 15. In this figure it will be observed that the flow pattern permits a very limited flow for the first 0.005 inch of travel, after which travel the flow proceeds linearly and at a very steep rate until reaching an effective saturation value. As the land 34 moves farther to the left, it will uncover progressively openings 236 of disk 170, 238 of disk 164, and 240 of disk 182. Since these openings communicate with large exit slots 242, 244 and 246, respectively, the flow increases steeply to saturation as shown.
From the foregoing, it will be appreciated that applicant has provided a valve structure which not only provides for a reasonably smooth flow vs. displacement pattern, particularly near null, but which is uniquely capable of dealing with the erosion or electrochemical milling action typical of high pressure hydraulic systems using phosphate-ester-based hydraulic fluids of the type currently used in commercial airline service. Each restriction or orifice is designed to a velocity which will not sustain the erosion or will not sustain it to an unacceptable degree. The variable throttling or metering control action may be permitted to erode initially but only to the point at which the pressure drop is reduced to a value at which the errosion ceases or is stabilized at a very low rate. The remaining throttling or meter control action may be permitted to erode initially but only to the point at which the pressure drop is reduced to a value at which the erosion ceases or is stabilized at a very low rate. The remaining throttling control-pressure drop at the variable metering area can be used quite effectively in that flow gain and pressure gain about null are still acceptable.
If the fixed restriction series does not erode and the variable restriction reaches a point of no erosion, the resultant system limits itself to a point within the allowable leakage since it has been designed to function in this manner. Where an initial zero overlap condition is created by the dimensions of the parts, some slight leakage will occur due to annular clearance and metering edge imperfections, and these edges will eventually break down causing increased leakage and further erosion. This will continue until a stable or nearly stable condition exists since, at this point, the metering edges have been eroded to the point of limiting further erosion. At this point the valve performance is similar to that of a typical underlapped valve. By forming the variable metering edges to presuppose an eroded condition, erosion could be limited from the beginning. This can be accomplished by chamfering the edges of the spool lands, for example.
Those skilled in the art will recognize that there are many configurations of orifices through disks which will give rise to any of a large number of different flow vs. displacement characteristics and also that very similar characteristics could be arrived at with somewhat different structure, depending upon various physical characteristics of the valve structure. If the travel of the spool valve member were very long or the lands particularly wide, more such disks or thicker such disks could be provided, and both thin and thick disks may be used with the thin disks preferably being used to control flow near null and thicker disks near the center of the stack. Obviously, the number of chambers and orifices used is variable with the application. A greater or lesser number of orifices could be used depending upon the pressure drop across the entire assembly. Care must be taken to avoid having an excessively high pressure drop across each orifice since this may result in erosion of the orifices. It may prove advantageous to use both comparatively large orifices and a large number of orifices to avoid possible plugging of the orifices while limiting the pressure drop across each orifice. Also, openings in the external surface of the stack may or may not have to be in the same disk as that containing the internal openings since this is a function of odd or even orifice staging. | Life extending means for a typical spool type servo valve consists of a stack of washer-like disks which cooperate to define a number of finely divided flow paths across the stack in which initial flow, as the spool valve is opened, is forced through alternating chambers and orifices with measured pressure drops across the orifices and wherein subsequent increments of valve travel expose large openings providing flow rates versus travel comparable to conventional spool type valves.
The individual disks may be made comparatively thin such that the thickness of two or more disks is required to provide a normal opening width into the stack. Thus a first disk and a second disk may have openings registering at identical positions to admit flow into the stack as a spool valve land passes the disks. The second disk also has a second opening or set of openings at another position on its inside edge so that as the land passes the second disk, it completes opening the first set of openings and begins exposing the second set of openings into the stack, etc. Thus the flow versus displacement characteristic of the valve may be made quite smooth since a new increment of flow into the stack may be added at every disk width. In another embodiment, flow is initially curtailed by being forced through a set of small series orifices only during a first increment of displacement corresponding to one disk width after which much larger openings are exposed in parallel to the orifices. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and a device for exchanging diagnostic data over a network, especially a network of the “switch fabric” type.
A network of the “switch fabric” type is based on a switched architecture, meaning that the terminal equipment items in charge of data emission and reception are organized around commutators (“switch” in English terminology) in charge of transporting these data and having N inputs and N outputs. Communication is achieved by sending and receiving of packets, which are emitted in parallel.
More generally, the invention relates, in a network for real-time simulation of aircraft components, to diagnostics for these components.
2. Discussion of the Background
Simulation of aircraft components is used to ensure development and integration of electronic and information-processing systems mounted on board aircraft, especially before the maiden flight.
The simulation architecture comprises a plurality of terminals also known as network nodes, each of these terminals performing simulation calculations or constituting an electronic interface making it possible to verify the operation of real equipment items of the aircraft. Thus this architecture comprises in particular a simulation terminal capable of exchanging data within a synchronous sequence by using the request/response principle.
The network nodes designate the main calculation node or the electronic input/output interface cards.
Data exchange between the different network nodes takes place over a specific UDP port (“User Datagram Protocol” in English terminology) and in real time, meaning that the simulation of the behavior of equipment items is achieved at their real operating speed. It is based in particular on a standard Ethernet protocol.
SUMMARY OF THE INVENTION
By transposing the AFDX topology (“Avionics Full DupleX” in English terminology), in which two networks are operated in parallel, for the purpose of redundancy in the context of simulation on a standard network, one solution consists in envisioning a topology with two switched networks guaranteeing segregation of flows:
a dedicated simulation network; and a dedicated diagnostic network.
Nevertheless, this solution suffers from real disadvantages: bulkiness and higher cost, because everything must be doubled (network switches, network cables, network interfaces of nodes, digital processing resources of nodes).
Thus one object of the present invention is to remedy at least one of the disadvantages of the techniques and processes of the described prior art. To achieve this, the invention proposes in particular a method and a device for exchanging diagnostic data between the nodes of the switched network while respecting the stringent constraints, such as no perturbation of the real-time progress of the simulation and of the associated data transfers.
The object of the invention is therefore a method for exchanging diagnostic data in a network between the client nodes of the network and a server node, also known as diagnostic terminal, connected to the network, each client node of the network being capable of receiving diagnostic commands and simulation commands in real time according to at least one predetermined time period, the method comprising time-based segregation for emission of the diagnostic data relative to processing of simulation commands.
The method according to the invention therefore makes it possible not to perturb the real-time execution of a simulation method.
According to a particular embodiment, the method comprises the following steps for determining the period during which diagnostic data may be emitted by the client nodes, in order to limit the simulation perturbations:
determination of the date of the end of processing of a simulation command; determination of the date of the next reception of a new simulation command as a function of the said at least one predetermined time period; determination of a time interval between the date of the end of processing of a simulation command and the date of the next reception of a new simulation command; and emission of diagnostic data via the network during the time interval determined in this way.
Advantageously, the method additionally comprises a step of shortening of the time interval by a defined duration, in order to limit the risks of interference between the simulation and diagnostic functions.
According to another particular embodiment, the emission of diagnostic data is effected by the client nodes only if the width of the emission window is sufficient, or in other words greater than a predetermined threshold, in order to take into account the time during which the network is being used by the diagnostic function.
Another object of the invention is a computer program that can be loaded into an information-processing system, the said program containing instructions permitting use of the method of exchanging diagnostic data in a network between a network node and a diagnostic terminal connected to the network as described in the foregoing, when this program is loaded and executed by an information-processing system.
Another object of the invention is a device for exchanging diagnostic data in a network between the client nodes of the network and a server node (diagnostic terminal) connected to the network, each client node of the network being capable of receiving diagnostic commands and of receiving simulation commands in real time according to at least one predetermined time period, the device comprising means for time-based segregation for the emission of diagnostic data relative to processing of simulation commands.
The device according to the invention therefore makes it possible not to perturb the real-time execution of a simulation method.
According to a particular embodiment, the device comprises the following means for determining the period during which diagnostic data can be emitted, in order to limit perturbations of the simulation:
means for determining the date of the end of processing of a simulation command; means for determining the date of the next reception of a new simulation command as a function of the said at least one predetermined time period; means for determining a time interval between the date of the end of processing of a simulation command and the date of the next reception of a new simulation command; and means for emitting diagnostic data via the network during the time interval.
Advantageously, the device additionally comprises means for reducing the width of the emission window by a defined duration, in order to limit the risks of interference between the simulation and diagnostic functions.
Advantageously, the means for emitting diagnostic data comprise means for comparing the time interval with a predetermined threshold, the means for emitting diagnostic data being suitable for emitting the diagnostic data if the width of the emission window is greater than a predetermined threshold, in order to take into account the time during which the network is being used by the diagnostic function.
Another object of the invention is a network node comprising the device for exchanging diagnostic data such as described in the foregoing.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages, objectives and characteristics of the present invention become evident from the detailed description hereinafter, provided by way of non-limitative example, with reference to the attached drawings, wherein:
FIG. 1 illustrates a simulation network architecture in which there is integrated a diagnostic terminal according to the invention; and
FIG. 2 presents a timing diagram illustrating the “emission windows” for a defined network node according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to the invention, the diagnostics for a network for simulation of components, especially aviation components, is centralized and integrated. This simulation is based on stringent real-time constraints, to the effect that it must not be perturbed in any way if the real behavior of components is to be optimally simulated.
The functionalities of the diagnostics are in particular the following:
determination of the network nodes that are present, especially in centralized manner, or in other words without using a point-to-point connection between a diagnostic tool and each of the input-output nodes; real-time monitoring, with the possibility of offsetting the monitoring and diagnostics graphic interface; establishment of mapping of network nodes and their configuration, especially the list of equipment items of the network and of software routines; looking up or modifying the assignment of parameters of network nodes; monitoring of the internal parameters and compilation of statistics; presetting of input/output paths and other parameters; real-time registration of parameters, especially in random-access memory; registration of breakdown contexts, especially in random-access memory; obtaining tables of parameter assignments, of configuration, of breakdown contexts and of registration; and managing of advanced statistics, such as the duration of processing of simulation messages, of the IP stack (“Internet Protocol” in English terminology) and of the message stack.
According to the invention, the diagnostic system is integrated into the simulation network and only a single network connection is necessary. In addition, the diagnostic function is centralized.
According to the invention, there is no load of additional terminals, and the investigation is undertaken in operational mode without disconnecting the nodes.
According to one embodiment of the invention, this is achieved in that the simulation network, illustrated in FIG. 1 , comprises a set of network nodes capable of operating together in order to effect simulation of the real environment that is not present and its electronic interface with the real environment that is present and comprises, for example, avionic calculators, actuators and transducers.
Thus each of the nodes 10 of network 5 is connected to a main switch 15 . These nodes 10 are especially calculating nodes, input/output cards, intermediate nodes and concentrators.
To this network 5 there are connected a main simulation calculator 20 (host in English terminology) on main switch 15 and a diagnostic equipment item 25 .
In order to respect real time as well as possible, the network is a high-speed network, such as a 100 Mbit/s or 1 Gbit/s network.
According to the invention, the simulation and diagnostic functions are segregated on the basis of space and time, or in other words are partitioned.
Segregation on the basis of space is effectively achieved by servers, especially by having a simulation terminal and a diagnostic terminal that are distinct.
The data are also segregated on the basis of time, since the time periods, known as “emission windows”, are positioned for communication of messages from the client nodes of the network to the diagnostic server terminal. These emission windows are obtained in particular by a synchronized algorithm used in the client nodes of the network.
Thus, according to the invention, the diagnostic data are inserted in the interior of the real-time data flow containing data of a simulation being transported, for example, via a proprietary maintenance protocol (UDP overlay).
In addition, on each of the client nodes of the network, especially on the nodes of “electronic interface” type, management by service (simulation or diagnostics) is achieved by relying on one specific UDP port to transport the simulation data and on another specific UDP port to transport the diagnostic data.
In addition, different lightweight execution processes (“threads” in English terminology) or tasks are executed on the network nodes in such a way as to manage each of the services and therefore each of the ports, especially one thread for execution of the simulation and one thread for execution of the diagnostics.
Thus each network node comprises a program (known as “plugin” in English terminology) that interacts with a main software routine, known as host program, to provide it with new functionalities. This program is a diagnostic program integrated in the operational application software of each node of the electronic interface.
The diagnostics can be achieved in synchronous mode or asynchronous mode (also known as “TRAP” mode in English terminology).
According to a synchronous embodiment, a diagnostic request makes it possible to launch specific processing on one node or on a set of given nodes, such as retrieval of tables of parameter assignments, registration, launching, stopping registration, presetting, modification of configuration, etc. At the end of processing, the response is emitted by the node or nodes that have been used.
According to an asynchronous embodiment, the diagnostics are activated by means of a unicast request, or in other words in point-to-point mode, or of a multicast request, or in other words by a request intended for a group of network nodes. Diagnostic data/statuses are then obtained periodically and automatically according to a programmable period.
According to the invention, the diagnostic equipment connected to the network must respect a certain number of rules in order to avoid perturbing the simulation being performed in real time. Effectively, it is preferred that data be emitted in unicast mode or even in multicast mode, but emission in broadcast mode, or in other words to all other points, is to be avoided so as not to inundate the network with messages.
In addition, it is just as important that the client nodes of the network not be perturbed by an excessively large flow of diagnostic requests. To achieve this, emission by the server node of data intended for a client node may be effected only in well-defined internals, such as every 10 ms, in the case of a simulation (if 10 ms if the minimal cycle for reception of a simulation command).
First, a specific request for identification of MAC addresses (acronym for “Medium Access Control” in English terminology), or in other words for a physical identifier stored in a network card or a network interface, used to globally attribute a unique address at the level of the link layer, which request is emitted by the diagnostic terminal before any other diagnostic exchange, makes it possible to establish MAC address/IP address pairs of network nodes on the basis of the identification responses. In this way, the diagnostic system positions static entries in its ARP buffer memory (acronym for “Address Resolution Protocol” in English terminology).
This request also makes it possible to position, at the network node level, a static entry in the ARP table, which entry corresponds to the MAC address/IP address pair of the diagnostic system.
Similarly, at the level of different network nodes, these must respect a certain number of rules.
In effect, the fragmentation of diagnostic messages upon emission is prohibited at the IP level. It must be effected at the level of the message layer in order to minimize the latency induced in the exchanges of simulation data (the nodes possess only a single network interface, via which the real-time simulation data and the non-real-time diagnostic data pass).
In addition, during the configuration phase, the IGMP protocol (acronym for “Internet Group Management Protocol” in English terminology) is used to configure the redirection table of the switch, making possible management of multicast IP addresses.
In addition, the electronic interface nodes of the network must respect the emission windows in order to emit the responses and the dispatches of messages in asynchronous mode.
Finally, emission of data in unicast mode must be given preference.
There now is described an algorithm that uses the emission window for diagnostic data. This algorithm is executed by the diagnostic task of the client nodes.
Each simulation data message is characterized by a pair comprising an identifier (ID) and a time period (T) in milliseconds as well as by an application data format.
Predefined beforehand for any simulation, a sequencing table comprising a set of pairs having an identifier and a time period is furnished by the simulation terminal to each node of the network during the configuration phase. Thus each node of the network possesses a specific sequencing table.
Starting from this table, each client node must then work by time-based sampling (“time slot” in English terminology).
According to one embodiment, the sampling period is one millisecond.
During reception of the first real-time data exchange message possessing the identifier Id k0 , each client node must, on the one hand, operate dynamic time warping, or in other words time-based initialization (t=0) and, on the other hand, must initialize a table of counters C such as described below:
C 1 =T 1 ,C 2 =T 2 , . . . ,C N =T N
Each of these counters C k then indicates the number of milliseconds remaining for each identifier ID k before the next reception of a simulation request denoted REQ[Id k ].
Thereafter, every millisecond, the network node effects an update of counter C k for all k. If the value of counter C k is strictly higher than 0 (C k >0), then the value of this counter is decremented by the value 1 (C k =C k −1).
Upon each reception of a simulation request (REQ[Id k ]), a request being by definition received every period T k ms, the algorithm on the one hand reinitializes counter C k to the value of the period T k (C k =T k ), and on the other hand administers statistics relating to the simulation data exchange messages. These statistics, used by the diagnostic function, make it possible to analyze the delays between the moments of theoretical reception and the moments of effective processing of the simulation requests REQ[Id k ].
At the completion of this operation, an emission window is available for all k as soon as counter C k is higher than a defined threshold Δ min (C k >Δ min ). During this emission window, each electronic interface node of the network is permitted to emit diagnostic data to the diagnostic terminal and to effect diagnostic processing operations, without nevertheless perturbing the real-time simulation in progress.
In addition, this algorithm thus guarantees that the latency induced by the diagnostic function in the sequencing of real-time data simulation (concurrent address over a single network interface) will be minimized.
The defined threshold Δ min must be adjusted in particular by taking the following elements into account.
First of all, the threshold takes into account the absolute value of a maximum negative offset (“glitch” in English terminology) of the main calculator that is emitting the simulation messages. This value is determined by the maximum lead times of the emissions of this main calculator at startup. Effectively, this phenomenon may occur during any cycle following a time lag: phenomenon of recovery of the operating system upon a time interruption.
In addition, the threshold must take into account the processing time for emission of a diagnostic response RESP[ID diagnostic ] operated by the core of the operating system used on the network node. In effect, the network node generally comprises a single network interface dedicated to the double role of simulation and diagnostics, which implies the use of a mutual exclusion mechanism (known as mutex for “Mutual Exclusion” in English terminology) in the UDP/IP protocol stack for synchronization, in order to guarantee that a shared resource will not be used at the same time by two distinct tasks.
Finally, the threshold must take into account the switching delay of the operation system during the changeover from the thread in charge of diagnostics to the thread in charge of simulation.
In FIG. 2 there is presented a timing diagram illustrating the emission windows for a defined network node.
According to this example, the network node receives simulation data or commands ID 1 every 10 ms, simulation data ID 2 every 3 ms and simulation data ID 3 every 5 ms.
By means of thick lines on the time scale, the timing diagram therefore illustrates the moment of reception of simulation data or commands, the time of processing of these data and the emission of the associated response.
Between these lines, the network node is capable of processing and emitting diagnostic data to the diagnostic server terminal.
Thus, since the emission windows are defined by the time available between two receptions and operations of processing of simulation data, shortened in such a way as to preserve the safety margin before any other reception of simulation data in real time, the reception and processing of simulation data are not perturbed.
In addition, problems of inversion of priority (by reason of the inevitable mutex on the network interface) if simulation and diagnostic data or commands arrive very close together at the UDP port of the network node are avoided in the same way.
According to the example under consideration, the width of each emission window therefore corresponds to the time interval between two receptions and operations of processing of simulation data shortened by one millisecond, the emission window beginning after emission of the simulation data.
According to the invention, the intrusive aspect of the diagnostic is negligible and is kept under control in the real-time simulation process.
According to this system, the latency time induced in the system is now determined. This time Δt[diagnostic request] induced , relative to the reception of a diagnostic request that would be inserted just before a simulation request, therefore comprises the time for physical transfer over the network node link, the time for processing of the UDP/IP stack during reception of the request, and the time for switching the simulation task to the diagnostic task.
According to one embodiment, the time for physical transfer over the network node connection is 15 μs, the time for processing of the UDP/IP stack during reception of the request is 400 μs and the time for switching the threads is 10 μs.
The latency Δt[diagnostic request processing] induced by processing this diagnostic request is zero, because of the fact that it is managed by a task of priority lower than that of simulation.
Similarly, the latency Δt[diagnostic response] induced by emission of the diagnostic response is zero, because of the fact that the algorithm determines and uses the emission windows appropriate for emitting the responses. Thus, according to this embodiment, the latency induced by the diagnostic over every simulation request is approximately equal to the time for processing of the UDP/IP stack during reception of the request, or approximately 400 μs, which is negligible compared with the minimal simulation cycle, or in other words the shortest delay separating the simulation messages, which delay is 10 ms here.
Thus the intrusive aspect of the diagnostic in the real-time simulation system is negligible.
Of course, numerous modifications may be made to the exemplary embodiments described in the foregoing without going beyond the scope of the invention. | A method and a device for exchanging diagnostic data for simulation of computer networks of aircraft are disclosed. Diagnostic data exchange is achieved in a network between a network node and a diagnostic terminal connected to the network. The network node is capable of receiving simulation commands in real time and diagnostic commands. According to the invention, the network node is capable of receiving simulation commands according to at least one predetermined time period, time-based segregation being achieved for emission of diagnostic data relative to processing of simulation commands. | 7 |
TECHNICAL FIELD OF THE INVENTION
Present invention relates to a device for thermokinetic property measurement. Particularly, present invention relates to a calorimeter useful as a device for the measurement of thermo kinetic properties. More particularly, present invention relates to a continuous flow device that measures the heat of reaction on a continuous basis.
BACKGROUND AND PRIOR ART OF THE INVENTION
Batch mode of reactions is followed widely, though conversion to continuous mode may be desirable in many cases. In batch mode of reactions, monitoring of reaction parameters such as heat transfer is carried out at the beginning and end of the reaction using batch mode calorimeters. Sampling during reaction is not possible.
Continuous flow synthesis has become an accepted approach for the synthesis of chemicals which were otherwise difficult to synthesize in conventional manner. The large heat transfer area per unit volume helps to carry out fast and exothermic reactions in a reliable manner. The same approach can be used to extract important features about the reaction viz. reaction rate constants, activation energy and also to some extent the thermodynamic parameters. However, to achieve this objective, it is necessary to have a compact and versatile device that can help to measure the reaction kinetics as well as heat of reaction in a quick manner.
Calorimeters that measure heat of reaction in batch reactions are marketed products. There are few reports in literature that attempt to measure heat of reaction and other thermokinetic properties in micro reactor based devices and processes and using LED display based calorimeters. But these prior art devices achieve measurement of thermokinetic properties at the beginning and end of reactions only, and are not designed to measure said properties in a continuous manner during the progress of a reaction.
WO2012097221 titled “System And Method For A Microfluidic Calorimeter” relates to a system for calorimetry comprising: a calorimetry apparatus comprising: a microfluidic laminar flow channel; at least two inlets in fluid connection with the laminar flow channel, the inlets allowing fluid to flow into the laminar flow channel; and a plurality of microscale temperature sensors disposed below the laminar flow channel at known positions relative to boundaries of the channel; and a processor in communication with the temperature sensors for calculating a calorimetry measurement based on local temperatures at the respective positions of the sensors in the channel derived based on data output by the microscale temperature sensors. The temperature sensors are nanohole arrays in a metal layer disposed below the laminar flow channel. But the drawback of this system is that it does not provide the extent of reaction progress at the point at which temperature is measured.
US2013121369 titled “Adiabatic Scanning Calorimeter” relates to an adiabatic scanning calorimeter for simultaneous measurements of the temperature dependence of heat capacity and enthalpy of liquids and solids and phase transitions, but the calorimenter does not have an option for monitoring the reaction and hence cannot be used to estimate the heat of reaction. It mainly functions as a temperature monitoring device. An article titled “Measuring enthalpy of fast exothermal reaction with micro-reactor-based capillary calorimeter” by K. wang, Y. C. Lu DOI: 10.1002/aic.11792 in AIChE Journal, Volume 56, Issue 4, pages 1045-1052, April 2010 discloses a new micro-reactor-based capillary calorimeter for the enthalpy measurement of fast exothermal reactions. The new calorimeter is operated in the continuous way. and the reaction enthalpy is measured with the online temperatures from detached sensor chips. A standard reaction system and an industrial reaction system are selected to test this new calorimeter with homogeneous and heterogeneous reaction processes. The measurement is taken at nearly adiabatic situations and the reaction enthalpy is calculated from the rising of temperature. High accuracy and good repeatability are obtained from this new calorimeter with relative experimental errors less than 3.5% and 2.4%, respectively. But this device may not be useful in isothermal conditions and the systems where phase change is possible. An other major drawback is that it does not track the reaction.
To overcome the drawbacks of the various cited devices and to provide a device which can be used as a flow reactor for synthesis and for discerning the reaction kinetics as well as as a flow calorimeter, the inventors disclose herein a calorimeter that functions as a device to measure reaction kinetics, preferably heat of reaction in a continuous manner, in adiabatic as well as in isothermal conditions. The device can be used independently for each of the above or simultaneously for any two or all of them together. Further, while the cited devices may measure the heat of reaction, none of the prior art devices can monitor the progress of the reaction continuously, which is necessary for the accuracy in the estimation of heat of reaction/dilution/dissolution/quenching With or without phase change during the reaction etc.
OBJECTS OF THE INVENTION
Main object of the present invention is to provide a calorimeter useful as a device for thermokinetic property measurement.
Another object of the present invention is to provide a continuous flow device to measure thereto kinetic properties in continuous manner.
Another object of the present invention is to provide a device that measures the heat of reaction independent of mode of measurement.
SUMMARY OF THE INVENTION
Accordingly, present invention provides a device for thermokinetic properly measurement to measure reaction kinetics, preferably heat of reaction in a continuous manner, in adiabatic as well as in isothermal conditions comprising a data management system ( 2 ) being connected. to a continuous flow and measurement section ( 3 ) and monitoring and processing unit ( 4 ) wherein said continuous flow and measurement section ( 3 ) further comprising a sectionalized jacket ( 301 ), the continuous flow sections for reaction mixture ( 304 ), assembly of four way thermally resistant connectors ( 305 ) for parallel flow of reaction mixture as well as the thermic fluid, inlet for the tube ( 307 ) carrying the reacting fluid, outlet for the tube ( 306 ) carrying the reacting fluid, inlet for the thermic fluid ( 302 ), outlet for the thermic fluid ( 303 ) wherein said assembly of four way thermally resistant connectors ( 305 ) for parallel flow of reaction mixture as well as thermic fluid ( 305 ) further comprising four way thermally resistant connectors ( 506 ), a temperature measurement device ( 501 ), a sealing section ( 502 ), outlet for withdrawing samples ( 504 ) regulated by a valve ( 503 ) for straight as well as coiled segment ( 304 ).
In an embodiment of the present invention, data management system ( 2 ) consisting a data acquisition system and a device to analyze the generated and acquired data.
In another embodiment of the present invention, temperature measurement device ( 501 ) used is selected from thermocouples, thermometers or IR sensors.
In yet another embodiment of the present invention, said temperature measurement device ( 501 ) is inserted through the tube wall at different spatial locations such that they touch the fluids flowing through the tube.
In yet another embodiment of the present invention, tubes ( 304 ) used is made out of metals, metal alloys, surface coated metallic tubes, polymeric tubes, and quartz tubes.
In yet another embodiment of the present invention, the cross section of the tubes ( 304 ) used is circular or cross-section made of straight edges viz. triangular, rectangular, pentagonal and hexagonal.
In yet another embodiment of the present invention, said device functions independently, as a standalone device or in combination with reactors, micro reactors or tubular reactors.
In yet another embodiment of the present invention, temperature at different locations was monitored online while the samples collected at different ports using different online (UV-Vis Spectrophotometer, IR probes and off-line (Gas Chromatography, HPLC, UPLC, MS) analysis techniques.
In yet another embodiment of the present invention, the acquisition of the measured temperature can be done through thermocouples through the wired or wireless data acquisition system.
In yet another embodiment of the present invention, said device measure reaction kinetics by using known method.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 represents schematic of the device ( 1 ) showing the assembly of thermokinetic property measurement system comprising of data. management system ( 2 ), the continuous flow and measurement section ( 3 ) and the monitoring and processing unit ( 4 ).
FIG. 2 represents the details of the the continuous flow and measurement section ( 3 ) comprising of a sectionalized jacket made from thermally resistant material ( 301 ), the continuous flow sections for reaction mixture ( 304 ), assembly of four way thermally resistant connectors ( 305 ) for parallel flow of reaction mixture as well as the thermic fluid, inlet for the tube ( 307 ) carrying the reacting fluid, outlet for the tube ( 306 ) carrying the reacting fluid, inlet for the thermic fluid ( 302 ), outlet for the thermic fluid ( 303 ).
FIG. 3 represents the assembly of the four way thermally resistant connectors ( 305 ) for parallel flow of reaction mixture as well as the thermic fluid comprises of four way thermally resistant connectors ( 506 ), a thermocouple ( 501 ), a sealing section ( 502 ), outlet for withdrawing samples ( 504 ) regulated by a valve ( 503 ) for straight as well as coiled segment ( 304 ).
FIG. 4 shows the details of the four way thermally resistant connector ( 506 ) facilitated with threaded or tapered sleeves ( 603 ) for connecting to jacket ( 305 ) and a set of end to end bores ( 601 ) for flowing the thermic fluid from one jacket section to the next and the bore to flow the reactants through the reaction tubes ( 602 ) and a bore connecting the section carrying the reacting fluids to the sampling port ( 604 ).
DETAILED DESCRIPTION OF THE INVENTION
The present invention brings out a device which can be used as a flow reactor for synthesis and for discerning the reaction kinetics as well as a flow calorimeter. The device can be used independently for each of the above or simultaneously for any two or all of them together.
A calorimeter that functions as a device to measure reaction kinetics, preferably heat of reaction in a continuous manner, in adiabatic as well as in isothermal conditions comprising a data acquisition system ( 2 ), continuous flow and measurement section ( 3 ) and monitoring and processing unit ( 4 ), said continuous flow and measurement section comprising a sectionalized jacket made from thermally resistant material ( 301 ), the continuous flow sections for reaction mixture ( 304 ), assembly of four way thermally resistant connectors for parallel flow of reaction mixture as well as thermic fluid ( 305 ), inlet for the tube carrying the reacting fluid ( 307 ), outlet for the tube carrying the reacting fluid ( 306 ), inlet for the thermic fluid ( 302 ), outlet for the thermic fluid ( 303 ) is disclosed herein.
The invention discloses a calorimeter that functions as a device to measure reaction kinetics, preferably heat of reaction/dilution/dissolution/quenching etc. with or without phase change in a continuous manner, in adiabatic as well as in isothermal conditions comprising data acquisition system ( 2 ), continuous flow and measurement section ( 3 ) and monitoring and processing unit ( 4 ), said continuous flow and measurement section comprising a sectionalized jacket made from thermally resistant material ( 301 ), the continuous flow sections for reaction mixture ( 304 ), assembly of four way thermally resistant connectors for parallel flow of reaction mixture as well as thermic fluid ( 305 ), inlet for the tube carrying the reacting fluid ( 307 ), outlet for the tube carrying the reacting fluid ( 306 ), inlet for the thermic fluid ( 302 ) and outlet for the thermic fluid ( 303 ).
The invention discloses a device for measurement of thermo kinetic properties comprising a tube ( 304 ) attached to the inlet of the thermostatic fluid of the reactor, a tube attached to the outlet of the fluid, at least one sampling port with a thermometer sensing device (viz. thermocouples, thermometers, IR probes) and a data management system to manage the temperature measurement and data generated by the device. The data management system further comprises a data acquisition system and a device, which uses the local temperature vs. time data for exploring the steady state features for reliable estimation of the heat of reaction, continuously. The spatiotemporal temperature data upon achieving the steady state was integrated over length and combined with the local composition using equation 2 to analyse the generated and acquired data. (refer FIG. 1 ).
Temperature data acquisition system ( 2 ) that uses the inputs from thermocouples in terms of electric signal is converted in the form of temperature.
The assembly of four way thermally resistant connectors ( 305 ) for parallel flow of reaction mixture as well as thermic fluid comprises four way thermally resistant connectors ( 506 ) for parallel flow of reaction mixture as well as the thermic fluid ( 305 ) comprising of a thermocouple ( 501 ), a sealing section ( 502 ), outlet for withdrawing samples ( 504 ) regulated by a valve ( 503 ) for straight as well as coiled ( 304 ) segment.
The enthalpies were estimated from the energy conservation in the system. Since the system can be maintained adiabatic as well as isothermal the energy conservation can be used to estimate the heat of dilution, dissolution, reaction etc. depending upon the mode of operation. For the case where the system is completely insulated, the reaction will take place at nearly adiabatic condition. The heat released from the reaction is transformed to the thermal energy thereby increasing the temperature of the reaction system. Since the tube material as well as the insulating material would have some heat capacity, there will be a finite loss of heat to them during the operation. These issues can be taken into account to establish a complete heat balance in the reactor system.
The device (with reference to FIG. 2 ) comprises of a tube ( 304 ) (having circular cross-section or cross-section made of straight edges viz. triangular, rectangular, pentagonal and hexagonal etc.) of any material (metal, alloys, polymeric, polymer composites, ceramic etc.) either in straight form of helical coil or spiral shape. Temperature measurement device (thermocouples, thermometers, IR probes) is inserted through the tube wall at different spatial locations such that they touch the fluids flowing through the tube. The locations of insert are made leak proof by using leak proof sealing. At the points of insert the tube has a port, which can act as an outlet or sampling port using a On-Off valve. The reacting/dissolving mixture enters the tube at the inlet. The fluids can be injected using any suitable dosing system viz. syringe pump for dosing liquid and a mass flow controlled gas supply from a gas cylinder.
The temperature at different locations was monitored online. The other ports at the locations where the local temperature is measured are used for taking the local reaction mixture sample to measure the composition. The extent of conversion or dissolution could be measured. This can be clone online using an online UV-Vis spectrophotometer or off-line sample analysis.
The following set of equations are used for the estimation of local enthalpy
Δ H r = Q L + Δ H n
Where QL is the thermal loss in the system, ΔH is the enthalpy rise in the system due to chemical/physical transformation and n is the number of moles. ΔH is estimated as
Δ H = ∫ T i n T m a x ∫ i m i C p i d T
where m i is mass flow rate of materials, Cp i is the specific heat capacity.
The device of the invention for measuring thermo kinetic properties functions independently, as a standalone device.
The device functions in combination with reactors, micro reactors or tubular reactors. Device may be connected to systems that function as reactors and also provide data with regard to various reaction parameters.
EXAMPLES
Following examples are given by way of illustration therefore should not be construed to limit the scope of the invention.
Example 1
The flow reaction calorimeter comprised of sections of specific length of polytetrafluoroethylene (PTFE) tubes connected to four-way connectors. While two opposite ports of the four-way connectors were used for connecting the tube, the other two opposite ports were connected to thermocouple and to the sample withdrawal section, respectively. Four such ports were used to measure the local temperature at four different locations along the length of tube. Water and concentrated sulfuric acid were dosed independently using syringe pumps. Residence time of liquids was varied in the range of 60 s to 300 s for the total volume of 1.4 ml of the tubular reactor. The entire system was insulated to avoid any heat loss. The losses were estimated using hot water at different flow rates and temperatures. Initial fluid temperature was 27° C. For a residence time of 60 s, the temperature at first thermocouple resulted in 114.2° C. while the temperature at the second and third thermocouple showed temperature of 102.3° C. and 70.6° C., respectively. From the data of mass flow rates, temperature difference and the estimated thermal loss the value of heat of dissolution was estimated and was 451.83 J/g.
Example 2
For the set-up explained in Example 1, when equal moles of sulfuric acid and sodium hydroxide were pumped separately and mixed, the temperature at the mixing point, the thermocouple alter 23 cm and 78 cm respectively rises to 31.8° C., 37.3° C. and 37.6° C., respectively. The estimated heat of neutralization comes to −59.42 J/g (±1.67%).
Example 3
For the set-up explained in Example 1, when equal moles of nitrating mixture and bromobenzene in acetic acid were pumped separately and mixed. The estimated heat of neutralization comes to −86.73 kJ/mol.
Example 4
For the set-up explained in Example 1, when equal moles of fuming nitric acid and acetophenone were pumped separately and mixed to react. The estimated heat of neutralization comes to −137 kJ/mol. With nitrating mixture the value comes to −189 kJ/mol.
Example 5
The flow reaction calorimeter comprised of sections of specific length of stainless steel (SS316) tubes connected to PTFE (polytetrafluoroethylene) four-way connectors having independent and parallel bores for flow of reacting fluids and the heat transfer fluid. Remaining two bores acted as ports for thermocouple and to the sample withdrawal section, respectively. Four such ports were used to measure the local temperature at four different locations along the length of tube. Fuming nitric acid and water were passed through the inlet of reacting channel [ 104 ] while water at ambient condition was used as the heat transfer fluid flowing through the jacket [ 305 ] made out of a thermally resistant material. At steady state, temperature was measured at different ports and samples were withdrawn to check the extent of dilution. Residence time of liquids was varied in the range of 20 s to 60 s for the total volume of 28 ml of the tubular reactor. The rise in the temperature in the water through jacket was monitored and used for the estimation of losses. Inlet fluid temperature was 25° C. For a residence time of 15 s, 30 s, 45 s and 60 s, the temperature at the respective thermocouples resulted in steady state values of 34° C., 46° C., 29° C. and 26° C., respectively. The extent of dilution at different residence times varied as 56%, 75%, 89% and 100%, respectively. From the data of mass flow rates, temperature difference and the estimated thermal loss the value of heat of dissolution was estimated and was 114.9 kJ/kg.
Example 6
Using the system described in Example 5 with a PTFE tube for flowing the reaction mixture, the apparatus was used for the measurement of heat of reaction between sodium hydroxide and ethyl acetate. Temperature of the reactants at the inlet was 20° C. and the residence time in the device was 10 minutes. At steady state, temperature was measured at different ports and samples were withdrawn to check the reaction progress. The jacket was kept empty and was connected to vacuum line to avoid any losses and operate the system at adiabatic condition. Samples were withdrawn from different outlets and analyzed. The temperature data at each position was monitored and used for the estimation of heat of reaction. The known value of the heat of reaction for this system is −73.9 kJ/mol. With reaction remaining incomplete event at the final outlet, the estimated heat of reaction based on the temperature rise alone (and the specific heat capacities of the reactants) varied between 77% to 85% of the known data depending upon the location of temperature data. Upon estimating the heat of reaction by knowing the exact composition of the reaction mixture at the point of temperature measurement, the estimated values varied in the range of 97-98.5% of the known values.
Advantages of the Invention
1. Online determination of thereto kinetic properties possible.
2. Continuous determination of thermo kinetic properties possible.
3. Applicable for determination in adiabatic as well as isothermal modes. | A device which can be used as a flow reactor for synthesis and for discerning the reaction kinetics as well as a flow calorimeter is a need in the art. To fulfill this need, the invention discloses a simple calorimeter that functions as a device to measure reaction kinetics, preferably heat of reaction in a continuous manner, in adiabatic as well as in isothermal conditions. The distinct advantages of the device include online determination of thermokinetic properties, continuous determination of thermokinetic properties and applicable for determination in adiabatic as well as isothermal modes. The device may function independently or may be used in combination with reactors, micro reactors or tubular reactors. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. application Ser. Nos. 12/338,899, 12/338,903 and 12/338,908, all filed on Dec. 18, 2008, which are incorporated herein by reference in their entirety. This application is a continuation of U.S. application Ser. No. 12/695,701, which was filed Jan. 28, 2010. U.S. Ser. No. 12/695,701 claims priority to U.S. provisional application 61/148,621, filed Jan. 30, 2009, both of which are Incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to coated oral solid dosage forms and to methods for testing the effectiveness of the coating on said solid dose.
BACKGROUND OF THE INVENTION
Eszopiclone, also known as (S)-zopiclone or (S)-(6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine), is formulated as the free base and is sold as LUNESTA®. It is used to treat different types of sleep problems, such as difficulty in falling asleep, difficulty in maintaining sleep during the night, and waking up too early in the morning. Most people with insomnia have more than one of these problems. See, e.g., WO 93/10787; Brun, J. P., Pharm. Biochem. Behav. 29: 831 832 (1988). The compound eszopiclone and various methods of treatment are disclosed at least in the following U.S. Pat. Nos. 7,125,874; 6,864,257; 6,444,673; 6,319,926; and 5,786,357.
Racemic zopiclone, rac-(6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine), also formulated as the free base, has been sold in Europe for many years to treat different types of sleep problems.
The active ingredient eszopiclone in its free base form has a very strong bitter taste. Human taste studies indicated that even a solution with very low concentration, e.g., 0.01 mg/mL, the bitter taste can be detected by the human tongue. Therefore, trace amounts of the active ingredient on the surface of the tablets, or any film coating defects leading to the direct exposure of the active ingredient on the surface of the tablets, or instantaneous dissolving tablets in human mouths would be detected owing to the extremely bitter taste when the patients swallow LUNESTA® tablets with water.
Many forms of analytical methods and apparatus have been proposed to measure or identify the active ingredient on the surface of the tablets. For instance, Raman mapping spectra were used to detect the active ingredient of alprazolam from the flattened surfaces of six alprazolam tablets (Sasic, Slobodan. Analytical R&D, Pfizer Global Research and Development, Sandwich, UK). Pharmaceutical Research (2007), 24(1), 58-65). Additionally, many analytical methods have been proposed to evaluate the film coating property of tablets. For example, the novel X-ray photoelectron spectroscopic (XPS) technique combined with principal component analysis of spectra-to-image datasets was employed to study the effects of atomization air pressure used during the coating process on film-tablet interfacial thickness (Barbash, Dmytro; Fulghum, Julia E.; Yang, Jing; Felton, Linda. Physical Electronics USA, Inc., Chanhassen, Minn., USA, Drug Development and Industrial Pharmacy (2009), 35(4), 480-486.) But none of these techniques are able to accurately determine very small amounts of material at very short time frames.
Human taste panel studies, such as the “Lick and Roll” testing method (a method involving direct collection of human saliva from the patients who take LUNESTA® tablets) is not only time-consuming, but also requires large and expensive clinical studies. Further, the conventional dissolution method is not capable of capturing the dissolution profiles of the tablets in the incipient stages of dissolution because sampling requires time intervals of five minutes or longer. On the other hand, methods such as conventional UV fiber optics and/or LC-UV methods, while rapid, are not sensitive enough to accurately quantify the trace amount of the active pharmaceutical ingredient at the ng/mL level. Therefore, there is a strong need to develop a new method which can overcome the drawbacks of the known methods or techniques in the art.
SUMMARY OF THE INVENTION
In one aspect, the present invention provides a pharmaceutical composition for oral administration as a solid dose comprising a therapeutically effective amount of (6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine) or (S)-(6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine), or a salt thereof, coated with a water-soluble polymeric coating, said polymeric coating comprising about 2% to about 10% by weight of the composition.
In another aspect, the present invention provides a composition which is capable of masking the taste of (6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine) or (S)-(6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine), or a salt thereof.
In another aspect, the present invention provides a process for preparing a pharmaceutical composition comprising providing from 0.5 to 5 mg of (6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine) or (S)-(6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine) or a salt thereof in the from of a tablet; and spray-coating the tablet with an aqueous dispersion comprising a cellulose derivative to provide a coating comprising about 2% to about 10% by weight of the composition.
In another aspect, the invention relates to a method for determining the presence of exposed core material in a coated solid oral dosage form comprising a core and a coating. The method comprises the following steps: (a) providing ex vivo a dissolution medium; (b) bringing the coated solid oral dosage form into contact with the dissolution medium; and (c) measuring a concentration of the core material dissolved in the dissolution medium within 5 minutes, or even within 60 seconds, of bringing the coated solid oral dosage form into contact with the dissolution medium. The method uses liquid chromatography and tandem mass spectroscopy (LC-MS/MS). The method may be used to determine trace amounts of a core material on the surface of a coated solid oral dosage form, to detect film coating defects, or to predict unpleasant taste of film coated tablets.
The invention is also directed towards a method for treatment, prevention, or amelioration of a sleep disorder in a subject comprising administering to a subject in need thereof, a composition described above. The invention further includes a method for treatment, prevention, or amelioration of anxiety in a subject comprising administering to a subject in need thereof, a composition described above.
In one aspect, the invention provides a use of a composition described above in the manufacture of a medicament for the treatment, prevention or amelioration of a sleep disorder.
In another aspect, the invention provides a use of a composition described above in the manufacture of a medicament for the treatment, prevention or amelioration of anxiety.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts conventional dissolution profiles of 3 mg Lunesta® (eszopiclone free base) tablets in various dissolution media.
FIG. 2 depicts conventional dissolution profiles of 3 mg eszopiclone maleate tablets in various dissolution media.
FIG. 3 depicts instantaneous dissolution profiles of 3 mg commercial Lunesta® tablets with standard coating (Opadry II, ˜4.5% weight gain).
FIG. 4 depicts instantaneous dissolution profiles of 3 mg eszopiclone tablets with Opadry TM coating (about 3.3% weight gain).
FIG. 5 depicts instantaneous dissolution profiles of 3 mg eszopiclone tablets with Opadry TM coating (about 8% weight gain).
FIG. 6 depicts instantaneous dissolution profiles of 3 mg eszopiclone tablets with standard (Opadry II) coating and Opadry TM coating (about 3.3%, 6% and 8% weight gain), averaged results, n=9-10 tablets.
DETAILED DESCRIPTION OF THE INVENTION
In one aspect, the invention provides a pharmaceutical composition for oral administration as a solid dose comprising a therapeutically effective amount of (6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine) or (S)-(6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine), or a salt thereof, coated with a water-soluble polymeric coating, the polymeric coating comprising about 2% to about 10% by weight of the composition. In some embodiments, the coating comprises an amount between about 3% to about 8% by weight of the composition, or preferably an amount between about 4% to about 7% by weight of the composition, or more preferably an amount between about 4% to about 6% by weight of the composition.
In some embodiments, the invention provides a pharmaceutical composition as described above wherein the coating comprises at least one cellulose derivative. The cellulose derivative can be selected from the group consisting of a cellulose ether and a cellulose ester. In some embodiments, the coating comprises at least one of hydroxypropyl methylcellulose, hydroxypropyl cellulose, methyl cellulose, hydroxyethyl cellulose or mixtures thereof.
In some embodiments of the invention, the coating comprises Opadry® tm (Colorcon, West Point, Pa.). In yet other embodiments, the invention provides that the coating comprises at least one taste modifying agent. Other exemplary coatings include Opadry® II in conjunction with Opadry® Clear (Colorcon, West Point, Pa.).
In a preferred embodiment, the solid dose is a tablet.
In some embodiments, the composition is capable of masking the taste of (6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine) or (S)-(6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine), or a salt thereof, for at least about 10 seconds, or preferably at least about 20 seconds, or more preferably at least about 30 seconds. In some embodiments, the invention provides a composition capable of masking the taste of eszopiclone for about 20 seconds, or for about 30 seconds, or for about 45 seconds.
In some aspects of the invention, the coating comprises at least a cellulose ether, an emulsifier and a plasticizer. Plasticizers can be added to the coating formulations to modify the physical properties. For example a plasticizer can be used to modify the glass transition temperature (Tg) of the polymer to make it more usable. The Tg is the temperature at which an amorphous polymer (or the amorphous regions in a partially crystalline polymer) changes from a hard and relatively brittle condition to a viscous or rubbery condition. Plasticizers function by decreasing the Tg of the polymer so that under ambient conditions the films are softer, more pliable and often stronger, and thus better able to resist mechanical stress. Non-limiting examples of plasticizers include polyethylene glycol having a molecular weight of 200 to 8000, glycerin, propylene glycol, glycerin triacetate, acetylated monoglyceride, triethylcitrate, tributylcitrate, acetyltrithylcitrate, acetyltributylcitrate, diethyl phthalate, and mineral oil. An emulsifier, or emulsifying agent, can be used to facilitate actual emulsification during manufacture of the coat, and also to ensure emulsion stability during the shelf-life of the product. For example, naturally occurring materials and their semi synthetic derivatives, such as the polysaccharides, as well as glycerol esters, cellulose ethers, sorbitan esters and polysorbates can be used as emulsifiers. Non-limiting examples of emulsifiers that can be used in the present invention include polysorbate, polyethylene (20) sorbitan monooleate, Tween 80, and sodium lauryl sulfate. One or more emulsifiers can be present in an amount up to about 2% by weight of the coat composition and preferably from about 0.1% to about 0.5% by weight of the coat composition. Any of the pigments heretofore used in making coating dispersions for coating tablets and the like can be incorporated in the coating. Examples are FD&C and D&C lakes, titanium dioxide, magnesium carbonate, talc, pyrogenic silica, iron oxides, channel black, and insoluble dyes. Also natural pigments such as riboflavin, carmine 40, curcumin, and annatto. In some embodiments, the invention provides that the coating comprises about 5-25% titanium dioxide, about 25-70% hydroxypropyl methylcellulose, about 0-10% polyethylene glycol and about 0-2% polysorbate, respective weight to weight. In other embodiments, the invention provides that the coating comprises about 10-20% titanium dioxide, about 50-70% hydroxypropyl methylcellulose, about 0-5% polyethylene glycol and about 0-1% polysorbate, respective weight to weight.
In preferred embodiments, the coating is an immediate release coating. In other embodiments, enteric coatings, and coatings for modifying the rate of release can be used. For example, such coatings can comprise hydroxypropyl methylcellulose, sodium carboxymethylcellulose, cellulose acetate, cellulose acetate phthalate, ethylcellulose, gelatin, pharmaceutical glaze, hydroxypropyl cellulose, hydroxypropyl methyl cellulose phthalate, methacrylic acid copolymer, methylcellulose, polyethylene glycol, polyvinyl acetate phthalate, shellac, sucrose, titanium dioxide, wax, or zein. The coating material can further comprise anti-adhesives, such as talc; plasticizers (depending on the type of coating material selected), such as polyethylene glycol, castor oil, diacetylated monoglycerides, dibutyl sebacate, diethyl phthalate, glycerin, propylene glycol, triacetin, triethyl citrate; opacifiers, such as titanium dioxide; and/or coloring agents and/or pigments.
The coating can include one or more materials suitable for the regulation of release or for the protection of the formulation. In one embodiment, coatings are provided to permit either pH-dependent or pH-independent release, e.g., when exposed to gastrointestinal fluid. In some embodiments, multiple active agents can be formulated into a single unit dosage form. For example, a pH-dependent coating serves to release the first active agent, second active agent, or both in the desired areas of the gastrointestinal (GI) tract, e.g., the stomach or small intestine, such that an absorption profile is provided which is capable of providing at least about twelve hours and preferably up to twenty-four hours of therapeutic benefit to a patient. When a pH-independent coating is desired, the coating is designed to achieve optimal release regardless of pH-changes in the environmental fluid, e.g., the GI tract. It is also possible to formulate compositions which release a portion of the dose in one desired area of the GI tract, e.g., the stomach, and release the remainder of the dose in another area of the GI tract, e.g., the small intestine. In certain embodiments, the first therapeutic agent is released in one area of the GI tract and the second therapeutic agent is released in a second area of the GI tract. In certain embodiments, the first and second therapeutic agents are released in nearly equal amounts at the same location in the GI tract.
In addition to the above ingredients, a coating can also contain suitable quantities of other materials, e.g. diluents, lubricants, binders, granulating aids, colorants, taste modifying agents and glidants that are conventional in the pharmaceutical art.
In other aspects of the invention, the coating comprises at least one “taste modifying agent.” As used herein, the term “taste modifying agent” is intended to refer to an agent capable of masking and/or changing the taste of the active ingredient. For example, taste modifying agents can include one or more sweetening agents, flavoring agents and/or cooling agents. The sweetening agent can be a sugar or may be a sugar substitute or mixtures thereof. Useful sweeteners include, but are not limited to, sugars such as sucrose, glucose (corn syrup), dextrose, invert sugar, fructose, and mixtures thereof; saccharin and its various salts such as the sodium or calcium salt; cyclamic acid and its various salts such as the sodium salt; the dipeptide sweeteners such as aspartame, alitame, neotame; sucralose, natural sweeteners such as dihydrochalcone compounds; glycyrrhizin; Stevia rebaudiana (Stevioside); sugar alcohols such as sorbitol, sorbitol syrup, mannitol, xylitol and the like, synthetic sweeteners such as acesulfame-K and sodium and calcium salts thereof and the like, hydrogenated starch hydrolysate (lycasin); protein based sweetening agents such as talin (thaumaoccous danielli) and/or any other pharmacologically acceptable sweetener known by the state of the art, and mixtures thereof.
The flavoring agents that can be used include those known to the skilled artisan, such as natural and artificial flavoring agents. These flavorings may be chosen from synthetic flavor oils and flavoring aromatics, and/or oils, oleo resins and extracts derived from plants, leaves, flowers, fruits and so forth, and combinations thereof. Representative flavor oils include: spearmint oil, cinnamon oil, peppermint oil, wintergreen, eucalyptus clove oil, bay oil, thyme oil, cedar leaf oil, oil of nutmeg, oil of sage, and oil of bitter almonds. Also useful are artificial, natural or synthetic flavors such as vanilla, chocolate, coffee, cocoa and citrus oil, including lemon, orange, grape, lime and grapefruit and fruit essences including apple, pear, peach, strawberry, raspberry, cherry, plum, pineapple, apricot and so forth, flavoring agents such as eucalyptol, thymol, camphor, methyl salicylate, benzaldehyde, ginger and the like, acidulants such as citric acid, malic acid and the like. Flavorings such as aldehydes and esters including cinnamyl acetate, cinnamaldehyde, citral, diethylacetal, dihydrocarvyl acetate, eugenyl formate, p-methylanisole, and so forth may also be used. Agents which can provide a sensation of heat may also be used. These include but are not limited to capsicum, capsaicinoids, pipperine, gingerols, isothiocyanates, and materials such as chili pepper, horseradish, ginger, black pepper and the like. Generally, any flavoring or food additive, such as those described in Chemicals Used in Food Processing, publication 1274 by the National Academy of Sciences, pages 63-258, may be used. These flavorings can be used individually or in admixture.
Agents known as cooling agents include, but are not limited to, menthol, substituted p-menthanes, e.g., hydroxymethyl and hydroxyethyl derivatives, menthyl succinate (PHYSCOOL), menthyl lactates (e.g. FRESCOLAT), N,N-dimethyl menthyl succinamide; substituted-p-menthane-3-carboxamides, such as N-ethyl-p-menthane-3-carboximide (WS-3), N,2,3-trimethyl-2-isopropyl butamide (WS-23); acyclic carboxamides, substituted cyclohexanamides, substituted cyclohexane carboxamides, substituted ureas and sulphonamides, and substituted menthanols; 3-1-menthoxy propan-1,2-diol, menthoxypropane diol, menthone glycerol ketals, p-menthane-3,8-diols, 2-mercapto-cyclo-decanone, 2-isopropanyl-5-methylcyclohexanol (ISOPREGOL); isopulegol, cubebol, incilin, xylitol and others compounds known for their cooling effects and mixtures thereof.
As used herein, the terms zopiclone, 6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine and [8-(5-chloropyridin-2-yl)-7-oxo-2,5,8-triazabicyclo[4.3.0]nona-1,3,5-trien-9-yl]-4-methyl piperazine-1-carboxylate refer to compounds represented by the following structure:
the terms Eszopiclone, LUNESTA®, (S)-(6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine) and [(9S)-8-(5-chloropyridin-2-yl)-7-oxo-2,5,8-triazabicyclo[4.3.0]nona-1,3,5-trien-9-yl]-4-methyl piperazine-1-carboxylate refer to an individual enantiomer of the foregoing represented by the following structure:
The pharmaceutical compositions of the invention contemplate both the racemic mixture (also known as zopiclone), and in certain embodiments, contemplate a single enantiomer, e.g., the S-enantiomer (eszopiclone). The term “zopiclone”, not otherwise modified or restricted will include not only a stereoisomeric mixture, but also individual respective stereoisomers substantially free from other stereoisomers. For example, zopiclone can encompass non-racemic mixtures of stereoisomers of the same compound (e.g., about 90, 80, 70, or 60 weight percent of one enantiomer and about 10, 20, 30, or 40 weight percent of the opposite enantiomer); and mixtures of different racemic or stereomerically pure compounds (e.g., about 90, 80, 70, or 60 weight percent of one compound and about 10, 20, 30, or 40 weight percent of another). Eszopiclone is the S-(+)-optical isomer of the compound zopiclone, which is described in U.S. Pat. Nos. 6,319,926 and 6,444,673, and in Goa and Heel (Drugs, 32:48-65 (1986)) and in U.S. Pat. Nos. 3,862,149 and 4,220,646. This isomer, which will hereinafter be referred to by its USAN-approved generic name, eszopiclone, includes the optically pure and the substantially optically pure (e.g., 90%, 95% or 99% optical purity) S-(+)-zopiclone isomer.
The compositions of the invention can be prepared by techniques known in the art. In this regard, the reader is referred to Remington's Pharmaceutical Sciences, 19th ed., Mack Publishing, Easton Pa. (1995), Chapters 92 and 93, the disclosures of which are incorporated herein by reference.
The starting materials and certain intermediates used in the synthesis of the compounds of this invention are available from commercial sources or can themselves be synthesized using reagents and techniques known in the art, including those synthesis schemes delineated herein. Racemic zopiclone is commercially available and can be made using various methods, such as those disclosed in U.S. Pat. Nos. 3,862,149 and 4,220,646. Eszopiclone can be made as described in U.S. Pat. No. 6,319,926.
Analytical methods described herein can be used for determining the presence of exposed core material in a coated solid oral dosage form. Such dosage forms comprise at least a core and a coating, and may comprise additional elements. The core material to be assayed may be an active ingredient or any other component of the core that happens to be of interest. Usually the component of most interest will be the active ingredient, but the method can be applied to other components such as binders, lubricants, disintegrating agents, etc. In many embodiments, the core will be a tablet core obtained by compression. The coating will usually be in the form of a film, which may be applied according to methods well known in the art, such as spray coating. Such techniques are described in standard textbooks, such as Remington: The Science and Practice of Pharmacy 19 th Ed. (1995) volume II, page 1615-1659, which is incorporated herein by reference. Depending on the function and nature of the coating, such coatings are commonly from 20 micron to 200 microns thick and comprise from 1 to 10% by weight of the total weight of the coated dosage form. Because thickness varies over a tablet (particularly if embossed), coating is usually measured by weight gain and not by thickness. Core material can arrive on the surface of a coated tablet either at the time of film coating (e.g. by dust deposition) or subsequent to coating (e.g. by film defects). The core material may also break through the film coating when the dosage is administered and the film is breached, either according to design or by film failure. In any of these circumstances, it may be desirable to monitor the presence of minute amounts (i.e. solutions <999 nM or <99 nM) of core material in “instantaneous” dissolution. As used herein instantaneous refers to times less than 60 seconds following exposure of the coated dosage form to a dissolution medium.
In an embodiment of the invention, the method comprises the following steps: (a) providing ex vivo a dissolution medium; (b) bringing the coated solid oral dosage form into contact with the dissolution medium; and (c) measuring a concentration of the core material dissolved in the dissolution medium within 60 seconds of bringing the coated solid oral dosage form into contact with the dissolution medium. Steps (a) to (c) may be repeated, whereby a plot of concentration vs time is obtained. The steps may be repeated so that multiple instances of measuring the concentration of core material occur within the 60-second time frame. The steps may also be repeated so that, although one or more measurements of concentration occur within 60 seconds, the plot of concentration vs time extends beyond the 60-second time frame. The relationship between time and concentration of the core material may be determined by (a) repeatedly bringing a single coated solid oral dosage form into contact with the dissolution medium in a single vessel at defined intervals; (b) repeatedly bringing a single coated solid oral dosage form into contact with the dissolution medium in a series of vessels at defined intervals; or (c) bringing a series of coated solid oral dosage forms into contact with the dissolution medium in a series of vessels at defined intervals. These approaches are described in further detail below.
In some embodiments, the dissolution medium is mammalian saliva or a chemically comparable solution containing amylase. The saliva may be human saliva. The saliva may be present at a concentration between 3% and 10% v/v, and the remainder of the dissolution medium may be water or an aqueous solution. In certain embodiments, the saliva or solution is present at a concentration of around 5%.
In certain aspects, the invention provides a method for treating, preventing or ameliorating various disorders using composition as described above. In one embodiment, the invention provides a method for treating and/or preventing sleep disorders.
Insomnia is characterized by difficulty in sleeping or disturbed sleep patterns. Insomnia can be of a primary nature with little apparent relationship to immediate somatic or psychic events, or secondary to some acquired pain, anxiety or depression.
In one aspect, the invention provides a method for treating or preventing a sleep disorder, including primary insomnia and sleep-awake rhythm disorders (e.g., work-shift syndrome, time-zone syndrome (jet-lag)), in a subject comprising administering to a subject in need thereof a composition as described above, such that administration of the composition treats the sleep disorder.
In another aspect, the invention provides a method for treating or preventing anxiety in a subject comprising administering to a subject in need thereof a composition as described above, such that administration of the composition treats the anxiety.
As used herein the term “anxiety” refers to an anxiety disorder. Examples of anxiety disorders treatable by the compositions and methods disclosed herein include, but are not limited to: panic attack, agoraphobia, acute stress disorder, specific phobia, panic disorder, psychoactive substance anxiety disorder, organic anxiety disorder, obsessive-compulsive anxiety disorder, posttraumatic stress disorder and generalized anxiety disorder. Anxiety as referred to herein also includes situational anxiety (e.g., as experienced by a performer prior to a performance).
In certain aspects, the racemic zopiclone can be utilized herein in the same manner as described for the S-isomer eszopiclone. However, it is recognized that use of eszopiclone can provide advantages over use of the racemic zopiclone and thereafter use of eszopiclone will be preferred for many applications.
The term “treating” or “treated” refers to administering a compound described herein to a subject with the purpose to cure, heal, alleviate, relieve, alter, remedy, ameliorate, improve, or affect a disease, the symptoms of the disease or the predisposition toward the disease.
“An effective amount” refers to an amount of a compound, which confers a therapeutic effect on the treated subject. The therapeutic effect can be objective (i.e., measurable by some test or marker) or subjective (i.e., subject gives an indication of or feels an effect). Effective doses will also vary depending on route of administration.
As used herein, and unless otherwise specified, the terms “prevent,” “preventing,” “prevention,” and “prophylactic” refer to the prevention of the onset, recurrence or intensification of a disorder disclosed herein. The terms “prevent,” “preventing,” “prevention,” and “prophylactic” include ameliorating and/or reducing the occurrence of symptoms of a disorder disclosed herein. The term “preventing” as used herein refers to administering a medicament beforehand to forestall or obtund an attack. The person of ordinary skill in the medical art (to which the present method claims are directed) recognizes that the term “prevent” is not an absolute term. In the medical art it is understood to refer to the prophylactic administration of a drug to substantially diminish the likelihood or seriousness of a condition, and this is the sense intended in applicants' claims. The reader's attention is directed to the Physician's Desk Reference, a standard text in the field, in which the term “prevent” occurs hundreds of times. No person of skill in the medical art construes the term in an absolute sense.
The coated compositions described above have exhibited improved taste characteristics relative to the uncoated compound, as demonstrated in the examples which follow.
Pharmaceutical compositions and dosage forms described herein comprise one or more active ingredients. Pharmaceutical compositions and dosage forms typically also comprise one or more pharmaceutically acceptable excipients or diluents.
The term “pharmaceutically acceptable,” as used herein, refers to a component that is, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and other mammals without undue toxicity, irritation, allergic response and the like, and is commensurate with a reasonable benefit/risk ratio. A “pharmaceutically acceptable salt” means any non-toxic salt that, upon administration to a recipient, is capable of providing, either directly or indirectly, a compound or a prodrug of a compound of this invention. Preferred pharmaceutically acceptable salts include the maleate, besylate, L-malate, mesylate, (R)-mandelate, succinate, citrate, fumarate, D-malate, D-tartrate, sulfate, L-tartrate and saccharine salts.
The invention also provides compositions comprising an effective amount of zopiclone, eszopiclone or salt thereof and an acceptable carrier. The carrier(s) must be “acceptable” in the sense of being compatible with the other ingredients of the formulation and, in the case of a pharmaceutically acceptable carrier, not deleterious to the recipient thereof in amounts typically used in medicaments.
Pharmaceutically acceptable carriers, adjuvants and vehicles that can be used in the pharmaceutical compositions of this invention include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, such as human serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene-block polymers, polyethylene glycol and wool fat.
Preparative methods include the step of bringing into association with the molecule to be administered ingredients such as the carrier that constitutes one or more accessory ingredients. In general, the compositions are prepared by uniformly and intimately bringing into association the active ingredients with liquid carriers, liposomes or finely divided solid carriers or both, and then if necessary shaping the product.
Single unit dosage forms are suitable for oral administration to a patient. Examples of dosage forms include, but are not limited to: tablets, caplets, capsules, such as soft elastic gelatin capsules and cachets.
The composition, shape, and type of dosage forms will typically vary depending on their use. Ways in which specific dosage forms encompassed by this invention will vary from one another will be readily apparent to those skilled in the art. See, e.g., Remington's Pharmaceutical Sciences, op. cit.
Typical pharmaceutical compositions and dosage forms comprise one or more excipients. Suitable excipients are well known to those skilled in the art of pharmacy, and non-limiting examples of suitable excipients are provided herein. The suitability of a particular excipient can also depend on the specific active ingredients in the dosage form. For example, the decomposition of some active ingredients can be accelerated by some excipients such as lactose, or when exposed to water. This invention encompasses pharmaceutical compositions and dosage forms that contain little, if any, lactose other mono- or di-saccharides. As used herein, the term “lactose-free” means that the amount of lactose present, if any, is insufficient to substantially increase the degradation rate of an active ingredient.
Lactose-free compositions of zopiclone can comprise excipients that are well known in the art. In general, lactose-free compositions comprise active ingredients, a binder/filler, and a lubricant in pharmaceutically compatible and pharmaceutically acceptable amounts. Preferred lactose-free dosage forms comprise active ingredients, microcrystalline cellulose, pre-gelatinized starch, and magnesium stearate.
This invention further encompasses anhydrous pharmaceutical compositions and dosage forms comprising active ingredients, since water can facilitate the degradation of some compounds. For example, the addition of water (e.g., 5%) is widely accepted in the pharmaceutical arts as a means of simulating long-term storage in order to determine characteristics such as shelf-life or the stability of formulations over time. See, e.g., Jens T. Carstensen, Drug Stability: Principles & Practice, 2d. Ed., Marcel Dekker, NY, N.Y., 1995, pp. 379 80. In effect, water and heat accelerate the decomposition of some compounds. Thus, the effect of water on a formulation can be of great significance since moisture and/or humidity are commonly encountered during manufacture, handling, packaging, storage, shipment, and use of formulations.
Anhydrous pharmaceutical compositions and dosage forms can be prepared using anhydrous or low moisture containing ingredients and low moisture or low humidity conditions. Pharmaceutical compositions and dosage forms that comprise lactose and at least one active ingredient that comprises a primary or secondary amine are preferably anhydrous if substantial contact with moisture and/or humidity during manufacturing, packaging, and/or storage is expected.
An anhydrous pharmaceutical composition should be prepared and stored such that its anhydrous nature is maintained. Accordingly, anhydrous compositions are preferably packaged using materials known to prevent exposure to water such that they can be included in suitable formulary kits. Examples of suitable packaging include, but are not limited to, hermetically sealed foils, plastics, unit dose containers (e.g., vials), blister packs, and strip packs.
The invention further encompasses pharmaceutical compositions and dosage forms that comprise one or more compounds that reduce the rate by which an active ingredient will decompose. Such compounds, which are referred to herein as “stabilizers,” include, but are not limited to, antioxidants such as ascorbic acid, pH buffers, or salt buffers.
Pharmaceutical compositions that are suitable for oral administration can be presented as discrete dosage forms, such as, but are not limited to, tablets (e.g., chewable tablets), caplets and capsules. Such dosage forms contain predetermined amounts of active ingredients, and can be prepared by methods of pharmacy well known to those skilled in the art. See generally, Remington's Pharmaceutical Sciences, 19th ed., Mack Publishing, Easton Pa. (1995).
Oral dosage forms can be prepared by combining the active ingredient(s) in an intimate admixture with at least one excipient according to conventional pharmaceutical compounding techniques. Excipients can take a wide variety of forms depending on the form of preparation desired for administration. Examples of excipients suitable for use in solid oral dosage forms (e.g., powders, tablets, capsules, and caplets) include, but are not limited to, starches, sugars, micro-crystalline cellulose, diluents, granulating agents, lubricants, binders, and disintegrating agents.
For example, a tablet can be prepared by compression or molding. Compressed tablets can be prepared by compressing in a suitable machine the active ingredients in a free-flowing form such as powder or granules, optionally mixed with an excipient. Molded tablets can be made by molding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent.
Examples of excipients that can be used in oral dosage forms include, but are not limited to, binders, fillers, disintegrants, and lubricants. Binders suitable for use in pharmaceutical compositions and dosage forms include, but are not limited to, corn starch, potato starch, or other starches, gelatin, natural and synthetic gums such as acacia, sodium alginate, alginic acid, other alginates, powdered tragacanth, guar gum, cellulose and its derivatives (e.g., ethyl cellulose, cellulose acetate, carboxymethyl cellulose calcium, sodium carboxymethyl cellulose), polyvinyl pyrrolidone, methyl cellulose, pre-gelatinized starch, hydroxypropyl methyl cellulose, (e.g., Nos. 2208, 2906, 2910), microcrystalline cellulose, and mixtures thereof.
Examples of fillers suitable for use in the pharmaceutical compositions and dosage forms disclosed herein include, but are not limited to, talc, calcium carbonate (e.g., granules or powder), microcrystalline cellulose, powdered cellulose, dextrates, kaolin, mannitol, silicic acid, sorbitol, starch, pre-gelatinized starch, and mixtures thereof. The binder or filler in pharmaceutical compositions of the invention is typically present in from about 50 to about 99 weight percent of the pharmaceutical composition or dosage form.
Disintegrants can be used to provide tablets that disintegrate when exposed to an aqueous environment. Tablets that contain too much disintegrant may disintegrate in storage, while those that contain too little may not disintegrate at a desired rate or under the desired conditions. Thus, a sufficient amount of disintegrant that is neither too much nor too little to detrimentally alter the release of the active ingredients should be used to form solid oral dosage forms of the invention. The amount of disintegrant used varies based upon the type of formulation, and is readily discernible to those of ordinary skill in the art. Typical pharmaceutical compositions comprise from about 0.5 to about 15 weight percent of disintegrant, preferably from about 1 to about 5 weight percent of disintegrant. Disintegrants that can be used in pharmaceutical compositions and dosage forms of the invention include, but are not limited to, agar-agar, alginic acid, calcium carbonate, microcrystalline cellulose, croscarmellose sodium, crospovidone, polacrilin potassium, sodium starch glycolate, potato or tapioca starch, other starches, pre-gelatinized starch, other starches, clays, other algins, other celluloses, gums, and mixtures thereof.
Lubricants that can be used in pharmaceutical compositions and dosage forms of the invention include, but are not limited to, calcium stearate, magnesium stearate, mineral oil, light mineral oil, glycerin, sorbitol, mannitol, polyethylene glycol, other glycols, stearic acid, sodium lauryl sulfate, talc, hydrogenated vegetable oil (e.g., peanut oil, cottonseed oil, sunflower oil, sesame oil, olive oil, corn oil, and soybean oil), zinc stearate, ethyl oleate, ethyl laureate, agar, and mixtures thereof. Additional lubricants include, for example, a syloid silica gel (AEROSIL 200, manufactured by W.R. Grace Co. of Baltimore, Md.), a coagulated aerosol of synthetic silica (marketed by Degussa Co. of Plano, Tex.), CAB-O-SIL (a pyrogenic silicon dioxide product sold by Cabot Co. of Boston, Mass.), and mixtures thereof. If used at all, lubricants are typically used in an amount of less than about 1 weight percent of the pharmaceutical compositions or dosage forms into which they are incorporated.
Eszopiclone, zopiclone, and the maleate, besylate, L-malate, mesylate, (R)-mandelate, succinate, citrate, fumarate, D-malate, D-tartrate, sulfate or L-tartrate salts thereof can, for example, be administered with a dosage ranging from about 0.001 to about 0.2 mg/kg of body weight, alternatively dosages between 0.1 mg and 15 mg/dose, or according to the requirements of the particular therapy. The methods herein contemplate administration of an effective amount of compound or compound composition to achieve the desired or stated effect. Typically, the pharmaceutical compositions of this invention will be administered from about 1 to about 6 times per day or alternatively, as a continuous infusion. Such administration can be used as a chronic or acute therapy. The amount of active ingredient that can be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. In some embodiments, such preparations contain from about 20% to about 80% (w/w) active compound. In some embodiments, such preparations contain from about 0.5% to about 20% active compound. A typical preparation will contain from about 0.5% to about 5% active compound (w/w).
Lower or higher doses than those recited above can be required. Specific dosage and treatment regimens for any particular patient will depend upon a variety of factors, including the activity of the specific compound employed, the age, body weight, general health status, sex, diet, time of administration, rate of excretion, drug combination, the severity and course of the disease, condition or symptoms, the patient's disposition to the disease, condition or symptoms, and the judgment of the treating physician.
Like the amounts and types of excipients, the amounts and specific types of active ingredients in a dosage form can differ depending on factors such as, but not limited to, the route by which it is to be administered to patients. In human therapy, the doses depend on the effect sought and the treatment period; taken orally, they are generally between 0.5 and 15 mg per day for an adult. For many applications, unit dosages containing 0.5 mg, 1 mg, 2 mg or 3 mg of eszopiclone or its salt will be suitable. In some embodiments, the unit dosages of the eszopiclone salts can be adjusted to contain the molar equivalent of 0.5 mg, 1 mg, 2 mg or 3 mg of eszopiclone freebase.
In another aspect, the invention relates to a novel instantaneous dissolution method that is accurate, reproducible and practical for both measuring the active ingredient on the tablet surface and for evaluating the effectiveness of film coatings. This method allows for the rapid and accurate determination of the concentration of the active ingredient—or other constituent of the core in a coated oral dosage form—present in a trace level by utilizing early dissolution solutions containing aqueous human saliva solution. Additionally, the results obtained from instantaneous dissolution method correlate well with the results of human taste panel studies, and thus are useful for predicting the outcome of these studies.
A typical procedure for preparing the instantaneous dissolution solutions of coated tablets is described as follows: a tablet comprising a core and a film coating—in this case a coated eszopiclone tablet—is randomly selected, and then placed into a basket sinker (e.g., Hanson Research Part # ENMISC, BSK008-JP 8 mesh, 0.76″ L×0.41″ W) with long handle (made from stainless steel tubing). The basket is then immersed in dissolution diluent (e.g., 5% human saliva solution) in vial 1 for 2-5 seconds, then moved to vial 2 for 2-5 seconds dipping and so on with the same tablet. The dissolution diluents (e.g., 5% human saliva solution in water) can be prepared by mixing thoroughly about 50 mL of normal human saliva and about 950 mL of water in a suitable container. About 5 mL of the 5% human saliva solution is then pipetted into several scintillation vials (approximately 20 mL volume). This procedure has been employed with tablets coated with about 2-4% coating by weight
Alternatively, the dipping experiment described above may be carried out by immersing the tablet in the basket in dissolution diluents (e.g., about 5% human saliva solution in water) in vial 1, moving the basket up and down for about 2-5 seconds at a speed of approximate 1 dip every two seconds; remove the basket from the diluent; take a sample of the diluent; re-immerse the tablet in the same vial. Continue the experiment similarly to collect samples until the tablet disintegrates or the preselected time course is completed, whichever comes first. In this embodiment, a new tablet is used in each vial. The experiment is repeated as described for additional nine or ten tablets (total of 10 tablets). The concentration of active ingredient, e.g., eszopiclone, in the sample solutions is then determined using LC/MS/MS (ESI mode, positive MRM scan type). The dissolution instantaneous profile of the tablets is constructed by plotting logarithmic concentration of eszopiclone versus time in seconds.
Another typical procedure for preparing the instantaneous dissolution solutions of coated tablets is described as follows: a number of tablets comprising a core and a film coating—in this case coated eszopiclone tablets—are transferred into basket sinkers and into a series of vials containing the dissolution diluents. The basket is then immersed in dissolution diluents (e.g., 5% human saliva solution in water) in vial 1 for 5 seconds, in vial 2 for 10 seconds, in vial 3 for 15 seconds dipping and so on with the series of tablets. The dissolution diluents (e.g., 5% human saliva solution in water) can be prepared by mixing thoroughly 50 mL of normal human saliva and 950 mL of water in a suitable container. About 5 mL of the 5% human saliva solution is then pipetted into several scintillation vials (approximately 20 mL volume). This procedure has been employed with tablets coated with 3-8% coating by weight.
In each scenario above, the concentration of core material, e.g., eszopiclone, the active ingredient in the sample solutions, is determined using LC/MS/MS (ESI mode, positive MRM scan type). The dissolution instantaneous profile of the tablets is constructed by plotting logarithmic concentration of eszopiclone versus time in seconds.
Suitable dissolution diluents include water, aqueous solutions, co-solvent solutions of water and organic solvents, human saliva solutions, solutions that mimic human saliva (particularly aqueous saline with amylase), buffer solutions, 0.01-0.1N HCl solutions and any other solutions which are able to dissolve the active ingredient and disintegrate the tablets in the instantaneous dissolution systems.
Described herein are instantaneous dissolution methods comprising a step using a LC/MS/MS technique to measure the concentration of the active ingredient in the instantaneous dissolution solution. Specifically, the LC/MS/MS procedure includes: centrifuge samples from above instantaneous dissolution solution at 6000×g for 5 minutes (if sample appears cloudy) to obtain clear solution; take out supernatant or clear solution and load into HPLC auto samplers. If the concentration of the active ingredient is above the upper calibration range (100 ng/mL), the sample solution will go through further dilution, for instance, by pipetting 100 μL of the centrifuged sample solution into 4.9 mL of sample diluents; If dilution sample is still above the calibration range, a serial dilution can be made with the dilution solution containing Internal Standard. Final diluted sample concentration should fall into the calibration range.
Suitable LC techniques include HPLC and UPLC. HPLC/MS/MS includes two parts: one part is HPLC, which is for separation the active ingredient from the sample matrix; the second part is mass spectroscopy (MS) or tandem mass spectroscopy (MS/MS) is for the detection of the active ingredient. A typical HPLC chromatographic condition is described as follows:
Guard Column. ACE guard column cartridge, 2.1 mm ID, C8 (ACE-122-0102GD) Analytical Column: ACE C8, 5 μm, 5 cm×2.1 mm (MAC-MOD ACE-122-0502) Mobile Phase: A: Water/0.05% Formic Acid; B: Acetonitrile Auto Sampler Temp.: 5° C. Column Temperature: 25° C. Flow Rate: 0.45 mL/min Injection Volume: 30 μL Needle wash ACN: H2O=50:50 (v/v) Minimum Run Time: 6.5 min
Time (Minutes)
% A
% B
Gradient Program:
0.0
90
10
2.0
5
95
3.1
5
95
3.2
90
10
6.5
90
10
Column Switch 100% column flow to waste for first 2.5 minutes
Make-up Solution ACN: H2O=50:50 (v/v)
Make-up flow into MS 0.45 mL/min
A typical mass spectrometer parameters and conditions are described as follows:
Scan Type: Positive MRM Ionization Model: ESI Gas 1: 8 Gas 2: 8 Curtain Gas: 10 Collision Gas: 8 psi Ionspray Voltage: 5500 volt Temperature: 450° C.
Dwell
DP
EP
CE
CXP
Compound Name
Q1
Q3
Time
(v)
(v)
(v)
(v)
Eszopiclone
389.1
245.1
200 ms
30
6
26
17
(RS)-Zopiclone-d8
397.1
245.1
200 ms
30
6
26
17
Both HPLC and MS parameters can be adjusted for optimum separation and sensitivity.
A typical HPLC-MS/MS analysis: Upon completion of the system suitability injections, single injections are made of each sample solution. The peak area ratio of active ingredient, e.g., eszopiclone to an internal standard (e.g., (RS)-Zopiclone-d8) is recorded. Concentration of the active ingredient, e.g., eszopiclone, in samples is calculated by extrapolating the sample/internal standard peak area ratio (y) from the calibration curve to the calculated concentration ratio on the x axis using Analyst 1.4.1 software or later version. The individual calculated concentration value and average concentration value for each time point are recorded and plotted as concentration in ng/mL as function of time in seconds for individual tablets, as shown in FIG. 3 , FIG. 4 or FIG. 5 . A plot of average concentration in ng/mL as a function of time in seconds for all tablets can also be made, as shown in FIG. 6 .
A summary of the HPLC-MS/MS method validation results can be found in the table below:
Validation Characteristic
Acceptance Criteria
Results
System Suitability
Evaluation against the criteria in
Method criteria was met
the method
Selectivity
No interfering peak in mobile
Chromatographic non-interference was
phase A, mobile phase B, dilution
established
solution and standard diluent
Accuracy and
Accuracy: 70.0-130.0%
Accuracy: 98.2% (93.7 to 103.2%)
Precision (Eszopiclone; 0.1 ng/mL
Precision: % RSD is NMT 10.0
Precision: % RSD = 2.9
to 100 ng)
Quadratic
Regression: correlation
Correlation coefficient is 1.00
Regression
coefficient is NLT 0.99
Time
seconds
Mean
% RSD
Evaluate and report % dissolved
5
5.317
57.9
results
10
6.875
7.1
15
7.461
17.1
20
14.144
46.2
25
12.222
38.3
30
16.625
31.9
35
22.404
45.5
40
14.658
34.1
45
14.989
17.3
50
12.477
14.3
Sample Solution
Absolute % Difference in the
Sample solutions are stable for 8 hours
Stability (Short Term)
initial peak area results for both
stored at room temperature
Eszopiclone and (RS)Zopiclone-
d8 and subsequent time points is
NMT 20.0% Absolute %
Difference in the initial peak area
ratio of Eszopiclone versus
(RS)Zopicolone-d8 and
subsequent time points is NMT
20.0%
For comparison with the methods disclosed herein, a conventional dissolution of 3 mg eszopiclone free base tablets or 3 mg eszopiclone maleate at physiological temperature (37° C.) can be tested in dissolution media at various pH values using Hanson Research SR8-Plus Dissolution Apparatus and C-Technologies Fiber Optic UV Probes at 305 nm (excipients subtracted at 410 nm). The typical dissolution media include 0.1N HCl, pH 4.5 acetate buffers, pH 5.5 phosphate buffer, pH 6.8 phosphate buffer. A standard dissolution protocol was used. The reference standard solution (0.006 mg/mL of eszopiclone free base) is prepared by weighing a known amount (˜20 mg) of the free base into a 100 mL volumetric flask. 10 mL of acetonitrile is added into the flask and sonicated until the solids dissolve completely. The solution is cooled to room temperature and made up to the 100 mL mark using dissolution medium and mixed well. From this stock solution, 3 mL is diluted to 100 mL using dissolution media. A volume of 500 mL of the dissolution medium is transferred to each of the 6 vessels in the dissolution apparatus and warmed to a temperature of 37° C. The Fiber Optic probes are immersed in each of the dissolution vessels and readings for the blank are taken for all the probes in the dissolution media. The readings for the standard are recorded for each of the individual vessels. The probes are then washed with the media and then inserted back into their respective vessels. One tablet is transferred into each vessel. The dissolution program is started immediately and readings are taken at 305 nm for 60 min (every 1 min for 20 min and then every 10 min). The conventional profiles of eszopiclone free base tablets and eszopiclone maleate tablets are shown in FIG. 1 and FIG. 2 , respectively.
FIG. 1 and FIG. 2 illustrate that the conventional dissolution method is useful to measure the dissolution profile of tablets over 45-60 minutes ranges and with a detection limit at μg/mL to mg/mL levels.
As is clear from FIG. 3-6 , the instantaneous dissolution method disclosed herein is able to measure the dissolution profiles of film coated tablets over 2-30 seconds, 2-60 seconds, or 2-120 seconds ranges and with a detection limit below 999 ng/mL.
The suitable active ingredients for study by the analytical method discussed above include any pharmaceutical compounds which can be incorporated into tablets. In the examples shown, the pharmaceutical compounds have an unpleasant taste. These include eszopiclone free base, eszopiclone L-malate, eszopiclone maleate or other acid addition salts; in some cases the active ingredient is eszopiclone free base.
In a further aspect, the current invention is related to the use of the instantaneous dissolution method to predict the outcome of the clinical human taste studies or correlate the data from clinical human taste studies. The clinical human taste studies are also referred as “Lick and Roll” testing. A typical procedure of the “Lick and Roll” testing includes a 2-part study in healthy subjects who are trained sensory panelists. Six tablet coating options are blinded and tested though the study is open-label, so that the panelist know all tablets are active. Taste panelists measure the onset of bitterness of the tablet variables using the intensity scale of the Flavor Profile method of descriptive sensory analysis (Keane, 1992). Seven points are used between 0 to 3 category scale where 0 is none and 3 is strong intensity. In Part 1, the panelists evaluate the tablets by licking the tablet surface (“Lick Test”) following a fixed sequence of the surface geometry, band and two faces, with six replicated evaluations at each geometry. The panelists record the number of licks required to reach a moderate intensity 2 of bitterness in every evaluation. In Part 2, the panelists evaluate the tablets by rolling tablets gently in the oral cavity (“Roll Test”), with three replicated evaluations. The panelists record the number of seconds required to reach a moderate intensity 2 of bitterness in every evaluation. The details of results are described in Example-5 of this application.
In summary, differences in tablet coating formulations and coating weight produced significant differences in bitter breakthrough, measured using a trained taste panel. Onset of bitter breakthrough can be delayed by increasing coating weight, applying a clear overcoat or modified coating formulation such as Opadry TM. The data from “Licks and Roll” method correlated well with that data from the instantaneous dissolution method. Therefore, the instantaneous dissolution method can be used to predict the human clinical taste study outcomes.
General Procedure for Coating
Preparation of Coating Suspension: Purified water is mixed with a water-soluble polymeric coating at room temperature (20° C.-25° C.) in a vortex. The ratio of solids to water in the coating suspension (solid content) is about 2% to about 20% (wt/wt), preferably about 3% to about 15% (wt/wt), and more preferably about 7% to about 13% (wt/wt). Mixing occurs at a vortex speed of 500 to 1000 rpm, for a period of time ranging from 20 to 60 minutes. A sample of the coating suspension is removed and a viscosity measurement is taken. The mixture is then de-aerated by mixing at a low speed in the vortex for at least 60 minutes.
Coating Procedure: The core solid dosage units (e.g., tablets) are loaded into an appropriate coating apparatus. Appropriate ranges for coating conditions may vary based on the coating equipment chosen; such differences may be found in the ratio of solids to water in the coating suspension preparation, target inlet temperature, spray rate, nozzle pressure, pan speed and air flow, among others. The set of ranges for various conditions utilized in the current invention depends on the size of the batch and the equipment.
The following non-limiting examples are illustrative of the invention.
Example 1
Eszopiclone 3.0 Mg Coated Tablets (Opadry® tm Coat)
18 kilograms of eszopiclone cores (3.0 mg per tablet) were coated with an Opadry coating dispersion. The Opadry dispersion of this example was made by mixing 14.58 kg of purified water with 1.62 kg of Opadry tm (07F99077, Blue), resulting in a 10% solids content, for 45 minutes in a vortex at 24° C. at 750 rpm. 100 g of the coating suspension was removed and found to have a viscosity of 336.5 cP (25° C.). The mixture was then de-aerated by mixing at a low speed for approximately one hour.
The 18 kg of core tablets (eszopiclone 3.0 mg, single dedusted cores) were loaded into a 24-inch O'Hara Labcoat Model IIX pan, which has 4 mixing baffles, a peristaltic pump, 96440-25 Masterflex tubing, 2 Spraying Systems guns (SUV113A), VF-3578-SS or VF-3578-316SS nozzles and VA113293-60-316SS or CO-VF-3578-SS air caps, for coating. The two spray guns were set to 35 g/min (70 g/min total spray rate). After 100 minutes, the desired 4.5% coating weight gain was achieved. The spraying conditions were as follows:
Tablet Load (kg)
18
Fluid Rate (g/min)
70
Atomizing Air (psi)
44
Air Temperature (° C.)
Inlet
68
Exhaust
41
Air Volume (cfm)
300
Pan Speed (rpm)
14
Coating Time (min)
100
% Weight Gain
4.5
The final coated tablets were evaluated by recording the weight of a sample of 100 tablets, grinding the 100 tablets in a mortar and pestle and determining the loss on drying of the sample using a Mettler Moisture Balance (5 g sample size, 105° C., 5 mg within 50 seconds free switch off mode). The coating uniformity of the coated tablets was evaluated using Laser Induced Breakdown Spectroscopy.
Example 2
A solids content range study was conducted on a 1 kg scale. The 7% and 10% solids content samples had comparable appearances, while the 13% solids content surface was rougher. The table below illustrates viscosity results and the run time required to achieve a 4% coating weight gain.
Run Time for 4%
Solids Content (%)
Viscosity (cP)
Weight Gain (min)
7
116
63
10
436
44
13
1180
32
Example 3
Taste Assessment
An open-label multiple-dose study of the taste profile of eszopiclone tablets was utilized to perform taste assessments. For the purpose of testing the compositions described above, the flavor profile panel consisted of four persons who have normal ability to smell and taste, have been trained in fundamental sensory principles and all aspects of the Flavor Profile technique and have considerable experience as panel members. The samples to be profiled were uniform and representative. Sample preparation and presentation were standardized and controlled.
The Flavor Profile is an art-recognized descriptive sensory analysis method used to measure the type and intensity of attributes in products and ingredients. [see Keane, P. The Flavor Profile Method. In C. Hootman (Ed.), Manual on Descriptive Analysis Testing for Sensory Evaluation ASTM Manual Series: MNL 13. Baltimore, Md. (1992).] It is based on the concept that flavor consists of identifiable taste, odor (aroma), and chemical feeling attributes, plus an underlying complex of attributes not separately identifiable. The method consists of formal procedures for describing and assessing the flavor of a product in a reproducible manner.
Tablet coatings were measured six times per surface, on both the band and the face of each tablet, by each sensory panelist. After each lick, the panelist waited several seconds to perceive any bitterness. The bitterness intensity results were obtained by using the Flavor Profile intensity scale (shown below), and the number of licks to a moderate (2) bitter intensity was recorded.
Flavor Profile Intensity Scale
0 = None
1 = Slight
2 = Moderate
3 = Strong
Six separate eszopiclone tablet types varying in coating type, thickness and amount of dedusting were tested:
Coating
Group ID
Coating
Weight
Dedusting
DD
Opadry ® II
4.5%
Double
(Double Dedusted)
TM
Opadry ® tm
4.5%
Standard
(Taste Mask)
UC
Opadry ® II
2.5%
Standard
(Under Coated)
OC
Opadry ® II
7.5%
Double
(Over Coated)
CC
Opadry ® II
4.5%
Double
(Clear Coat)
Opadry ® Clear
1-2%
ND
Opadry ® II
4.5%
None
(Not Dedusted)
The data set was analyzed using repeated measures Analysis of Variance (ANOVA), and the band and face data were analyzed separately. A Bonferroni pairwise comparison test was used to determine significant differences between sample types. The face and band data were highly correlated (r=0.94, data not shown), and the face of the tablet took longer for the bitter taste to break through than the band.
The coating types were found to have significant differences in mean licks to bitter breakthrough, as shown in FIG. 1 . In this figure, coating samples sharing the same vertical line are not statistically different.
The coating types fall into three distinct groups:
Group III: Opadry tm (4.5% coating, TM), Opadry II (7.5% coating, OC) and Opadry II plus Opadry Clear (4.5% coating and 1-2% coating, respectively; CC) required a greater number of licks to bitter breakthough than the other groups.
Group II: Opadry II double dedusted (4.5% coating, DD) and Opadry II non-dedusted (4.5% coating, ND). Dedusting showed no effect on reducing bitter breakthrough.
Group I: Opadry II (2.5% coating, UC) produced the quickest bitter breakthrough.
Tablets of other strengths can be prepared by altering the ratio of active ingredient to pharmaceutically acceptable carrier, the compression weight, or by using different punches.
Example-4
Conventional Dissolution of 3 mg Commercial Lunesta Tablets
Conventional dissolution of 3 mg eszopiclone free base tablets at physiological temperature (37° C.) was tested in dissolution media at various pH values using Hanson Research SR8-Plus Dissolution Apparatus and C-Technologies Fiber Optic UV Probes at 305 nm (excipients subtracted at 410 nm). The dissolution media used were (a) pH 1 0.1N HCl prepared by mixing 50 mL of conc HCl in 6 L of water; (b) pH 4.5 acetate buffer (20 mM) prepared by dissolving 5.88 g of sodium acetate trihydrate in 6 L of water and adjusting the pH to 4.5 with acetic acid; (c) pH 5.5 phosphate buffer (20 mM) prepared by dissolving 16.3 g of potassium dihydrogen phosphate in 6 L of water and adjusting the pH to 5.5 with NaOH; (d) pH 6.8 phosphate buffer (20 mM) prepared by dissolving 16.3 g of potassium dihydrogen phosphate in 6 L of water and adjusting the pH to 6.8 with NaOH. A standard dissolution protocol was used. The standard solution (0.006 mg/mL of eszopiclone free base) was prepared by weighing a known amount (˜20 mg) of the free base into a 100 mL volumetric flask. 10 mL of acetonitrile was added into the flask and sonicated until the solids dissolved completely. The solution was cooled to room temperature and volume made up to the 100 mL mark using media and mixed well. From this stock solution, 3 mL was diluted to 100 mL using media. A volume of 500 mL of the dissolution medium is transferred to each of the 6 vessels in the dissolution apparatus and warmed to a temperature of 37° C. The Fiber Optic probes are immersed in each of the dissolution vessels and readings for the blank are taken for all the probes in the dissolution media. The readings for the standard are recorded for each of the individual vessels. The probes are then washed with the media and then inserted back into their respective vessels. One tablet was transferred into each vessel. The dissolution program was started immediately and readings were taken at 305 nm for 60 min (every 1 min for 20 min and then every 10 min). The dissolution profiles of 3 mg Commercial Lunesta Tablets in various media are shown in FIG. 1 .
Example 5
Conventional Dissolution of 3 Mg Eszopiclone Maleate Tablets
Dissolution over time of 3 mg eszopiclone maleate tablets at physiological temperature (37° C.) was tested in dissolution media at various pH values using Hanson Research SR8-Plus Dissolution Apparatus and C-Technologies Fiber Optic UV Probes at 305 nm (excipients subtracted at 410 nm). The dissolution media used were (a) pH 1 0.1N HCl prepared by mixing 50 mL of conc HCl in 6 L of water; (b) pH 4.5 acetate buffer (20 mM) prepared by dissolving 5.88 g of sodium acetate trihydrate in 6 L of water and adjusting the pH to 4.5 with acetic acid; (c) pH 5.5 phosphate buffer (20 mM) prepared by dissolving 16.3 g of potassium dihydrogen phosphate in 6 L of water and adjusting the pH to 5.5 with NaOH; (d) pH 6.8 phosphate buffer (20 mM) prepared by dissolving 16.3 g of potassium dihydrogen phosphate in 6 L of water and adjusting the pH to 6.8 with NaOH. A standard dissolution protocol was used. The standard solution (0.006 mg/mL of eszopiclone free base) was prepared by weighing a known amount (˜20 mg) of the free base into a 100 mL volumetric flask. About 10 mL of acetonitrile was added into the flask and sonicated until the solids dissolved completely. The solution was cooled to room temperature and made up to the 100 mL mark using media and mixed well. From this stock solution, 3 mL was diluted to 100 mL using media. A volume of 500 mL of the dissolution medium is transferred to each of the 6 vessels in the dissolution apparatus and warmed to a temperature of 37° C. The Fiber Optic probes are immersed in each of the dissolution vessels and readings for the blank are taken for all the probes in the dissolution media. The readings for the standard are recorded for each of the individual vessels. The probes are then washed with the media and then inserted back into their respective vessels. One tablet was transferred into each vessel. The dissolution program was started immediately and readings were taken at 305 nm for 60 min (every 1 min for 20 min and then every 10 min). The dissolution profiles of 3 mg eszopiclone maleate tablets are shown in FIG. 2 .
Example 6
Instantaneous Dissolution of 3 mg Eszopiclone Tablets with Standard Coating (2-4.5% Weight Gains)
This procedure is applicable for preparing the instantaneous dissolution solutions of eszopiclone tablets or any tablets coated with less weight gain (2-4.5% standard coating weigh gains). The instantaneous dissolution profile of eszopiclone tablets was obtained in 5% human saliva solution in water using an HPLC/MS/MS method. The 5% human saliva solution in water was prepared by mixing thoroughly 50 mL of normal human saliva (pooled, special screening by Biochemed) and 950 mL of water (Milli-Q) in a suitable container. For the preparation of instantaneous dissolution sample solution, 5 mL (using 5 mL Eppendorf pipette) of the 5% human saliva solution was pipetted into several scintillation vials (approximately 20 mL volume). The Lunesta® tablet was placed into a basket sinker ((Hanson Research Part # ENMISC, BSK008-JP 8 mesh, 0.76″ L×0.41″ W) with long handle (made using stainless steel tubing). The basket was then immersed in vial 1 for 2 seconds, then moved to vial 2 for 2 seconds dipping and so on. The experiment was stopped when the tablet started disintegrating. The experiment was repeated as described for additional nine tablets (total of 10 tablets). The concentration of Eszopiclone in the samples was determined using LC/MS/MS (ESI mode, positive MRM scan type). The dissolution profile of Lunesta® tablets was obtained by plotting logarithmic concentration of eszopiclone against time in seconds, as shown in FIG. 3 or FIG. 4 .
Example 7
Instantaneous Dissolution of 3 mg Eszopiclone Tablets with TM Coating (3-8% Weigh Gains)
This procedure is applicable for preparing the instantaneous dissolution solutions of Lunesta tablets or any tablets coated with higher weight gain (3-8% TM coating weigh gains). The instantaneous dissolution profile of Lunesta® (Eszopiclone) tablets was obtained in 5% human saliva solution in water using an HPLC/MS/MS method. The 5% human saliva solution in water was prepared by mixing thoroughly 50 mL of normal human saliva (pooled, special screening by Biochemed) and 950 mL of water (Milli-Q) in a suitable container. For the preparation of instantaneous dissolution sample solution, 5 mL (using 5 mL eppendorf pipette) of the 5% human saliva solution was pipetted into several scintillation vials (approximately 20 mL volume). The Lunesta® tablet was placed into a basket sinker ((Hanson Research Part # ENMISC, BSK008-JP 8 mesh, 0.76″ L×0.41″ W) with long handle (made using stainless steel tubing). The tablet was kept below the surface of the liquid at all times, and the basket was moved up and down for 10 seconds at a speed of approximate 1 dip every two seconds. This procedure was repeated 5-10 times using separate tablets and vials. The scintillation vials were labeled using (i.e. 10-1, 10-2 and so on up to 10-6) accordingly. The experiment was continued similarly in a fresh vial till the tablet disintegrated, in separate vials containing the dissolution diluents (e.g., 5% human saliva solution), or till the tablet disintegrates, whichever comes first, in separate vials containing the dissolution diluents (e.g., 5% human saliva solution). The concentration of active ingredient, e.g., eszopiclone, in the samples was then determined using LC/MS/MS (ESI mode, positive MRM scan type). The dissolution instantaneous profile of Lunesta® tablets was constructed by plotting logarithmic concentration of eszopiclone against time in seconds, as shown in FIG. 5 or FIG. 6 .
While the foregoing examples of the instantaneous profile relate to the determination of presence of active ingredient, it will be apparent to persons of skill that the method can be applied to the determination of concentrations of other core materials as well. For example, if a tablet core contained, in addition to active ingredient, an excipient whose taste was offensive, one could use the same method to determine breakthrough of the excipient.
Example 8
Human Clinical Taste “Lick and Roll” Tests on 3 mg Eszopiclone Tablets with TM Coating
Methods: This was a 2-part study in healthy subjects who were trained sensory panelists. Six tablet coating options were blinded and tested though the study was open-label that panelist knew all tablets were active. Taste panelists measured the onset of bitterness of the tablet variables using the intensity scale of the Flavor Profile method of descriptive sensory analysis (Keane, 1992). Seven points were used between 0 to 3 category scale where 0 is none and 3 is strong intensity. In Part 1, the panelists evaluated the tablets by licking the tablet surface (“Lick Test”) following a fixed sequence of the surface geometry, band and two faces, with six replicated evaluations at each geometry. The panelists recorded the number of licks required to reach a moderate intensity 2 of bitterness in every evaluation. In Part 2, the panelists evaluated the tablets by rolling tablets gently in the oral cavity (“Roll Test”), with three replicated evaluations. The panelists recorded the number of seconds required to reach a moderate intensity 2 of bitterness in every evaluation.
Results and Discussions: The mean number of licks of the tablet bands ranged from 2.92 licks for Formulation UC to 8.38 licks for Formulation OC, with a 95% confidence interval of 1.63 licks. The mean lick values on the face were similar to the band with one transposition—Formulation TM requiring the most licks to bitter breakthrough, with a smaller 95% confidence interval of 0.56 licks. The mean roll values ranged from 12.4 to 23.2 seconds with Formulation UC requiring the least time and Formulation OC tablets requiring the most. The roll test data are highly correlated with the lick test data.
Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents of the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims. | Coated tablets of (6-(5-chloro-2-pyridyl)-5-[(4-methyl-1-piperazinyl)carbonyloxy]-7-oxo-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine) are provided. The tablets minimize the perceived bitterness of the medicament. A method for analyzing instantaneous dissolution of sub-microgram quantities of core material is also disclosed. | 0 |
BACKGROUND
The control of noise in the home, office, factory, automobile, train, bus, airplane, etcetera involves reducing the travel or transmission of both airborne noise and structure borne noise, whether generated by sources within or outside your environment.
Airborne noise is produced initially by a source which radiates directly into the air. Many of the noises we encounter daily are of airborne origin; for example, the roar of an overhead jet plane, the blare of an auto horn, voices of children, or music from stereo sets. Airborne sound waves are transmitted simply as pressure fluctuations in the open air, or in buildings along continuous air passages such as corridors, doorways, staircases and duct systems. The disturbing influences of airborne noise generated within a building generally are limited to areas near the noise source. This is due to the fact that airborne noises are less intense and are easier to dissipate than structure borne noise.
Structure borne noise occurs when floor or other building elements are set into vibratory motion by direct contact with vibrating sources such as mechanical equipment or domestic appliances, footsteps, falling of hard objects, objects being moved, bounced or rolled across the floor, to name a few examples. In a building for example, the vibrational or mechanical energy from one floor or wall assembly is transmitted throughout the structure to other wall and floor assemblies with large surface areas, which in turn are forced into vibration. These vibrating surfaces, which behave somewhat like the sounding board of a piano, amplify and transmit the vibrational energy to the surrounding air, causing pressure fluctuations resulting in airborne noise to adjacent areas. The intensity of structure borne noise produced by a wall or floor structure when it has been forced into vibration is generally more intense and harder to dissipate than an airborne sound wave. Unlike sound propagated in air, the vibrations of structure born noise are transmitted rapidly with very little attenuation through the skeletal frame or other structural paths of the building and radiate the noise at high levels.
Since there are so many environments such as roofing, siding, appliances, automobiles, and airplanes to name a few, where this invention can be used, we will concentrate on flooring for the remainder of this patent since there are established standards, test methods and independent testing laboratories that can test and validate floor systems for the reduction of airborne and structure borne noise. Also floors constitute an important focus for sound insulation between living areas in multi-family or single-family dwellings. Floors allow the transmission of airborne and especially structural borne noise to adjoining rooms and building structure.
In North America, acoustical consultants, architects, builders, contractors and homeowners rely on sound testing to help gauge the performance of a floor and ceiling assembly for evaluation and comparison to determine how well the floor and ceiling assembly insulates against impact and airborne noises. The International Building Code (IBC) requires minimum ratings of 50 or above for both the Impact Insulation Class (IIC) and Sound Transmission Class (STC) sound tests performed in a controlled environment to measure the amount and extent of sound vibration or noise that travels from one living area to another.
The Impact Insulation Class utilizes American Society for Testing and Measurement (ASTM) standards ASTM E 492 and ASTM E 989 for testing the ability to block impact sound by measuring the resistance to transmission of impact noise or structure borne noise by simulating footfalls, objects dropped, rolled or bounced on the floor, to name a few. The Sound Transmission Class comprises ASTM E 90 and ASTM E 413 and evaluates the ability of a specific construction assembly to reduce airborne sounds, such as voices, stereo systems, and televisions to name a few. Both tests involve a standardized noise making apparatus in an upper chamber and a sound measuring system in a lower chamber. Decibel measurements are taken at various specified frequencies in the lower chamber. Those readings are then combined using a mathematical formula to create a whole number representation of the test, the higher the number, the higher the resistance to noise.
Many condominium associations have adopted the International Building Code minimum ratings of 50 for both the Impact Insulation Class and Sound Transmission Class sound tests for floor and ceiling assemblies. It should be noted that non-laboratory, “Field” tests for Impact Insulation Class (FIIC) and for Sound Transmission Class (FSTC) are also recognized by the International Building Code. These sound tests utilize the same testing methods which are used for Impact Insulation Class and Sound Transmission Class tests but are conducted in situ in an actual building after the floor installation is completed. The International Building Code suggests ratings of 45 or higher for Field Impact Insulation Class and Field Sound Transmission Class testing.
Another test that more directly evaluates impact sound of underlayment materials is ASTM E-2179, also known as the “Delta” test. This test basically consists of two Impact Insulation Class tests conducted over the same concrete sub-floor. One test is over the bare concrete subfloor (no flooring materials) and the other is over the concrete sub-floor with floor covering material and underlayment included. The measured Impact Insulation Class values are compared to the reference floor levels defined in the standard and adjusted to provide the Impact Insulation Class the covering would produce on the reference concrete floor. The Delta Impact Insulation Class or Improvement of Impact Sound Insulation is obtained by subtracting 28 (the value for the reference bare floor from the standard) from the adjusted Impact Insulation Class of the whole assembly. As long as the same floor covering material is used, one can conduct a series of Delta tests to evaluate various underlayment materials.
It is important to note that Impact Insulation Class and Sound Transmission Class tests are not single component tests, but an evaluation of the whole floor/ceiling assembly, from the surface of the floor covering material in the upper unit, to the ceiling in the lower unit. An integral part of a report for any of these sound tests is a detailed description of the floor/ceiling assembly used in the test. The Impact Insulation Class rating of a floor should be equal to or better than its Sound Transmission Class rating to achieve equal performance in controlling both airborne and structure bore sound.
Concrete slab flooring is used extensively throughout the world in buildings and homes. A concrete slab finished with a hard surface such as ceramic tiles is the prevalent floor structure for many commercial and institutional buildings. The ceramic tiles over a concrete slab provide an aesthetically pleasing, durable and smooth surface. Because of their easy maintenance and very long durability, ceramic tiles over a concrete slab, have the lowest lifetime cost of any flooring.
On average, the concrete slab by itself has a Sound Transmission Class value around 50 and meets the International Building Code requirements. However, the Impact Insulation Class rating for typical concrete slabs is relatively low, 25 to 28 on average depending on the thickness of the concrete slab and is well below the International Building Code requirement of 50 minimum. The reason for the low Impact Insulation Class rating numbers is due to the transmission of high frequency sounds through the slab and into the room below. Hard-finish flooring materials (e.g., ceramic tiles) adhered directly to concrete slabs does not improve the Impact Insulation Class rating achieved by the concrete itself. Thus, concrete slabs finished with ceramic tiles or similar materials provide low Impact Insulation rating values and the addition of a noise reduction layer is essential to reduce impact noise for this type of extensively used floor structure.
The addition of an acoustic ceiling, if included as part of the floor and ceiling assembly, will cause an increase in both the Impact Insulation and Sound Transmission rating numbers, so the test becomes less critical when acoustic ceilings are part of the floor and ceiling assembly. Adding an acoustical ceiling to the home or office can be very expensive and adds additional labor and material costs. It would be desirable to have a floor system by itself, as defined in this patent, meet the International Building Code requirements without the added costs and labor associated with installing an acoustical ceiling.
Several methods have been used in the past to try to meet the International Building Code requirement for the Impact Insulation Class rating of a 50 minimum for the concrete slab with a hard-finish tile surface as mentioned above. One method used primarily in new construction or during renovating a structure consists of using a “floating” floor option. This method isolates the concrete slab floor from the substructure using various isolation techniques in an effort to reduce the impact noise through the floor structure as seen in FIG. 1 below.
This option is very expensive and requires extra space in renovating a building or in new construction and is not practical in many existing buildings today.
A second option used in industry today is to use a resilient layer or underlayment between the concrete slab and the hard ceramic tile finish surface in new construction or when renovating a floor in an existing building. This option is more advantageous because it is less expensive, easier to install and can be used in an existing building without reducing the overall living space of a room needed to isolate a floor structure.
There are several types of underlayments in the market used to reduce sound between a concrete slab and a hard tile surface that appears to meet the Impact Insulation Class rating of 50 minimum but each of these materials has a disadvantage. These materials are shredded or foamed rubber, natural and synthetic cork mats, natural fiber mats and modified and non-modified bituminous membranes. Shredded or foamed rubber can be very expensive, hard to install, is very heavy 1.0 to 1.4 lbs/square foot at a 6 mm thickness and it requires 6 mm of thickness to meet the Impact Insulation Class 50 minimum rating required by the International Building Codes. Cork (both natural and synthetic) and natural fiber mats can reduce the noise and approach the International Building Code requirements of 50 minimum Impact Insulation Class rating if thick enough, but these materials are not recommended for wet or humid areas since mold and mildew can develop over time and can cause health problems. Modified and non-modified bituminous membranes appear to be a good choice for use as a sound proof underlayment since they can act as a vapor barrier and are chemical resistant, easy to install, durables and are not prone to mold growth. Unfortunately, current bitumen and modified bitumen membranes in the market for floor underlayments have failed to reach the Impact Insulation Class rating of 50 minimum required by the International Building Code.
There appears to be a genuine need for a membrane that meets the International Building Code requirements for Impact Insulation Class and Sound Transmission Class ratings of 50 minimum that is easy to install that is light weight that is lower in thickness that can be used in wet or humid environments to reduce potential mold growth at a reasonable installed cost.
SUMMARY OF THE INVENTION
A novel self adhered membrane for use in homes, industries and environments where excess noise can be a detriment which: (1) reduces impact and airborne sound transmission; (2) is easy to install; (3) is thin (less than 2 mm thick); (4) is lightweight (less than 0.3 lbs/square feet); (5) has an improved tensile adhesive strength; (6) reduces labor required; (7) is environmentally safe; and (8) is ecologically friendly. The membrane can be used as part of the floor, roofing and/or wall system in buildings, automobiles, spacecraft, appliances, etcetera, wherever noise reduction is desired.
A sound barrier membrane disclosed herein meets these requirements and overcomes all of the detriments of the existing options mentioned. The disclosed membrane further provides or acts as a crack isolation, vapor barrier and sound barrier membrane combined into one single underlayment. This single underlayment meets the International Building Code Impact Insulation and Sound Transmission Class ratings as tested by a fully accredited testing facility for acoustical and structural testing, achieving a 50 Impact Insulation Class rating and 52 Sound Transmission Class rating tested between a 6 inch concrete slab and a hard ceramic tile flooring without an acoustic ceiling. This is the most cost effective floor and ceiling construction used in many buildings today and the hardest to pass the IBC requirements of 50 minimum for the IIC and STC due to the minimum thickness of the concrete slab and the use of hard ceramic tiles as a flooring material.
Acoustic tests on the disclosed sound membrane performed by an accredited third party testing laboratory verified that the present invention meets the sound requirements established by the International Building Code. Acoustic tests were carried out over 6 inch concrete slab and stoneware tile as flooring surface with and without acoustic ceiling. The following ratings were obtained: Impact Insulation Class 50 and Sound Transmission Class 52 without acoustic ceiling and Impact Insulation Class 70 and Sound Transmission Class 66 with acoustic ceiling.
The disclosed sound membrane also meets all the requirements of ANSI A118.12 and A118.13 for crack isolation and sound reduction membrane for flooring applications. Furthermore, a critical property for flooring application is tensile adhesion strength. The disclosed membrane was is tested according to ISO 13007 for ceramic tiles, grouts and adhesives. The importance of this test is to warranty good structural integrity and bonding of the underlayment to the concrete slab over time, the higher the tensile adhesive strength values the better. The disclosed sound membrane shows an increase of up to 225% for the adhesive strength values over competitive membranes that are offered in the industry today and exceeds the established current standard for this test standard.
Table 1 and 2 summarizes the Impact Insulation Class and Sound Transmission Class test results and the tensile adhesive strength values, respectively. A, B, C, and D are existing products offered in the market today for use as sound reduction membranes and were tested by a certified independent laboratory.
TABLE 1
Independent Certified Laboratory Test results for Impact Insulation (IIC) and
Sound Transmission Class (STC) rating with no acoustic ceiling.
Disclosed sound
A
B
C
D
membrane
IIC (ASTM 492/E 989)
48
46
49
46
50
6″ concrete slab/no acoustic ceiling
STC (ASTM E90, E413)
50
50
51
52
52
6″ concrete slab/no acoustic ceiling
TABLE 2
Tensile adhesion test results
Disclosed Sound
A
B
C
D
Membrane
Tensile adhesion strength,
44
42
20
28
65
psi (ISO 13007-1)
No existing sound proof membrane meets the sound requirements at the weight and thickness of the underlayment disclosed herein. The disclosed underlayment membrane which is positioned between the concrete slab and hard tile surface consists of a decoupling layer, a barrier layer and dampening layer in such a way as to prevent noise vibrations from being transmitted to the surrounding environment. The decoupling layer reduces the transmission of sound waves while the barrier layer prevents the dampening layer from penetrating the decoupling layer and imparts some rigidity to the system and acts in part like a secondary decoupling layer that contributes to dissipating sound vibrational energy. The dampening layer acts as a dampening material with sound absorbing, sound reducing characteristics that can also have viscoelastic and elastic properties or non-viscoelastic properties depending on the material used and can also act as an adhesive to attach the membrane to the concrete. The dampening material is capable of storing strain energy when deformed, while dissipating a portion of this energy through hysteresis.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of the typical existing floating floor.
FIG. 2 is a cross-sectional view of typical embodiment.
FIG. 3 is a cross-sectional view of another embodiment.
FIG. 4 is a cross-sectional view of another embodiment.
FIG. 5 is a cross-sectional view of another embodiment.
DETAILED DESCRIPTION
FIG. 2 is a schematic cross-sectional view of the construction of one embodiment. A generic example of the construction consists of a decoupling layer 1 , typically adhered with an adhesive layer 2 to a barrier layer 3 with a dampening layer 4 adhered to the opposite side of the barrier layer. The separation of decoupling layer 1 from the dampening layer 4 enhances the sound reduction properties. A release material 5 can be used to prevent the dampening layer from sticking to itself if the material is wound into a roll or stacked on top of itself.
A decoupling layer is a material used in the separation of previously linked systems so that they may operate independently. The decoupling layer separates the barrier layer from the surface to be applied on the sound barrier membrane, such as tile, which will applied on the sound barrier membrane. The decoupling layer also helps reduce sound transmission. The decoupling layer 1 can consist of various types or combinations of materials. Examples of the materials which can act as a decoupling layer are but not limited to fabric, foam, rubber and or cork but other materials can also be used. These materials can be used alone or in combination at different basis weights and thicknesses. Some examples of fabrics include but are not limited to polyester, glass, polypropylene, polyethylene, nylon or other manmade fibers, cotton or other natural fibers untreated or treated to prevent mold growth or any combination thereof. Examples of foam which can be used include but are not limited to urethane, polypropylene, polyethylene, rubber and or silicone to name a few, or any combination thereof. It should be noted in the case of flooring that the first decoupling layer should typically have a minimum porosity of about 50-300 cubic ft/square foot/minute using an 11 mm nozzle as measured using ASTM D 737 Standard Test Method for Air Permeability of Textile Fabrics using a Frazier Differential Pressure Air Permeability Tester. This allows penetration of the mortar, cement, glue, thin-set or any other material used in the industry to ensure adhesion to tiles, wood or other flooring materials to decoupling layer 1 for good mechanical bonding typically have a minimum of 20 PSI tensile adhesive strength as tested by the Pull Out Test Method. Thus the tiles, wood or other floor surfacing materials stay bonded, secure and affixed to the decoupling layer 1 during the service use of the material. Decoupling layer 1 should also resist mold and moisture and should maintain its integrity in the alkaline environment common in flooring applications.
A barrier layer is a material that blocks or impedes something. The barrier layer 3 is used primarily to separate decoupling layer 1 from dampening layer 4 enhancing the ability of the decoupling layer 1 to reduce sound transmission. The barrier layer 3 can consist of rigid and semi-rigid materials at different basis weights and thicknesses. The barrier layer must be somewhat stiff to maximize the effect between the dampening layer and the barrier layer. It prevents the dampening layer 4 from penetrating decoupling layer 1 if dampening layer 4 is a liquid or in a liquid state when it is applied to barrier layer 3 so that decoupling layer 1 can maximize the decoupling effect and channel the vibrational energy away from dampening layer 4 . Barrier layer 3 also helps to dissipate vibrational energy so that the barrier layer 3 in combination with dampening layer 4 allows vibrational energy to be converted to heat reducing vibrational noise from being transferred to the room below it. The rigid and semi-rigid materials can be used alone or in various combinations and can consist of but are not limited to aluminum, copper, steel, nickel, zirconium, vanadium, lead and tungsten to name a few of the materials that can be used to form a barrier layer for specific applications. Conductive ceramics can be also used, such as tantalum nitride, indium oxide, copper silicide, tungsten nitride, and titanium nitride to name a few. Other possible materials include but are not limited to polyester, polypropylene, polyethylene, vinyl or other plastic foam or plastic sheets alone or in combination unfilled or filled with mineral materials.
The dampening layer 4 utilizes a material which dampens or reduces the transmission of sound waves. Dampening is the action of a substance or of an element in a mechanical or electrical device that gradually reduces the degree of oscillation, vibration, or signal intensity, or prevents it from increasing. For example, sound-proofing technology dampens the oscillations of sound waves. Built-in dampening is a crucial design element in technology that involves the creation of oscillations and vibrations. Dampening layer 4 has viscoelastic and or elastic properties that help dissipate vibrational energy and turn it into heat reducing sound transmission.
Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like honey, resist shear flow and strain linearly with time when a stress is applied. An elastic material is the physical property of a material that returns to its original shape. Elastic materials strain instantaneously when stretched and just as quickly return to their original state once the stress is removed. Viscoelastic materials have elements of both of these properties and, as such, exhibit time dependent strain. Whereas elasticity is usually the result of bond stretching along crystallographic planes in an ordered solid, viscosity is the result of the diffusion of atoms or molecules inside an amorphous material.
Viscoelastic materials used for dampening layer 4 can be but are not limited to bitumen, modified bitumen that consists of but is not limited to bitumen (asphalt) blended with styrene butadiene rubber, styrene butadiene styrene rubber, styrene isoprene styrene rubber, styrene ethylene butylene styrene rubber, natural rubber, recycled tire rubber with or without mineral filler, oils or stabilizers with or without tackifying resins, atactic polypropylene, ethylene propylene copolymer, or other rubber types like: acrylic rubber, butadiene rubber, butyl rubber, chlorobutyl, chlorinated polyethylene, chlorosulphonated polyethylene, epichlorohydrin ethylene oxide rubber, ethylene-propylene rubber, fluoroelastomer, hydrogenated nitrile rubber, isoprene rubber, natural rubber, nitrile rubber, perfluoroelastomers, polychloroprene, polynorbornene rubber, polysulfide rubber, polyurethane rubber, silicon and fluorosilicon rubber, styrene butadiene rubber, tetra-flouroethylene polypropylene or any combination thereof, cork, polypropylene foam, urethane foam, silicone foam, or rubber to name other viscoelastic, elastic or dampening materials. All of these can be utilized in any combination, weight and thickness.
Some of the dampening materials are adhesive in nature and thus may not need a separate adhesive layer. If needed an adhesive layer 6 can be factory applied or applied on site in the field to bond the barrier layer 3 to the dampening layer 4 . ( FIG. 3 ) The bond between the decoupling layer 1 and the barrier layer 3 can also be achieved by using an adhesive layer 2 consisting of glues such as Albumin, Casein, Meat, Canada balsam Coccoina, Gum Arabic, Latex, Starch, Methyl cellulose, Mucilage, Resorcinol resin, Urea-formaldehyde resin, Polystyrene cement/Butanone, Dichloromethane, Acrylonitrile, Cyanoacrylate, Acrylic, Resorcinol, Epoxy resins, Ethylene-vinyl acetate, Phenol formaldehyde resin, Polyamide, Polyester resins, Polyethylene, Polysulfides, Polyurethane, Polyvinyl acetate, Polyvinyl alcohol, Polyvinyl chloride, Polyvinyl chloride emulsion, Polyvinylpyrrolidone, rubber cement and Silicones. Additional means to create the adhesive layer 2 which are known in the industry include but are not limited to pressure sensitive adhesives, contact adhesives, heat sensitive, heat activated, welding, curtain coating, kiss coating, spraying or other methods known to those adept in the industry.
The barrier layer 3 may be bonded to the dampening layer 4 during manufacturing or applied in the field as a separate layer. The dampening layer 4 could have adhesive characteristics so that it adheres to the barrier layer 3 without an additional adhesive layer 2 . Also the dampening layer 4 can be applied in a molten or liquid form to the barrier layer 3 during manufacturing of the material or in the field. This bond can be achieved by using various glues or techniques know in the industry and include but are not limited to glues like Albumin, Casein, Meat, Canada balsam Coccoina, Gum Arabic, Latex, Starch, Methyl cellulose, Mucilage, Resorcinol resin, Urea-formaldehyde resin, Polystyrene cement/Butanone, Dichloromethane, Acrylonitrile, Cyanoacrylate, Acrylic, Resorcinol, Epoxy resins, Ethylene-vinyl acetate, Phenol formaldehyde resin, Polyamide, Polyester resins, Polyethylene, Polysulfides, Polyurethane, Polyvinyl acetate, Polyvinyl alcohol, Polyvinyl chloride, Polyvinyl chloride emulsion, Polyvinylpyrrolidone, Rubber cement and Silicones. Additional techniques include but are not limited to: pressure sensitive adhesives, contact adhesives, heat sensitive, heat activated, heat welding, curtain coating, kiss coating, spraying or other methods known to those adept in the industry.
In one specific embodiment, the construction of the invention is as shown in FIG. 2 . The decoupling layer 1 consist of a polyester or polypropylene fabric or mat with a basis weight of 50 to 450 grams per square meter and is bonded using a urethane or acrylic based adhesive layer 2 to a barrier layer 3 consisting of an aluminum foil with a thickness of 0.1 to 5.0 mils. The barrier layer 3 is then coated with a dampening layer 4 consisting of a styrene butadiene, styrene Isoprene styrene, modified bitumen pressure sensitive adhesive with a thickness of 0.1 to 5 mm and a propylene silicone release liner 5 .
In a second specific embodiment as shown in FIG. 2 , the decoupling layer 1 consists of a polyester or polypropylene fabric or mat with a basis weight of 100 to 300 grams per square meter and is bonded using a urethane or acrylic based adhesive layer 2 to a barrier layer 3 consisting of an aluminum foil with a thickness of 0.6 to 2.0 mils. The barrier layer 3 is then coated with a dampening layer 4 consisting of a styrene butadiene, styrene Isoprene styrene, styrene butyl rubber, hydrocarbon resin, paraffinic or naphthenic oil, calcium carbonate modified bitumen pressure sensitive adhesive with a thickness of 0.2 to 2 mm and a propylene silicone release liner 5 .
In a third specific embodiment as shown in FIG. 2 , the decoupling layer 1 consists of a polyester or polypropylene fabric or mat with a basis weight of 160 to 200 grams per square meter and is bonded using a urethane or acrylic based adhesive layer 2 to a barrier layer 3 consisting of an aluminum foil with a thickness of 0.8 to 1.2 mils. The layer 3 is then coated with a dampening layer 4 consisting of a styrene butadiene, styrene Isoprene styrene, styrene butyl rubber, hydrocarbon resin, paraffinic or naphthenic oil, calcium carbonate modified bitumen pressure sensitive adhesive with a thickness of 0.5 to 1.2 mm and a propylene silicone release liner 5 .
In a fourth specific embodiment, one or more additional layers may be added. The additional layer(s) may include multiple decoupling layers and or multiple barrier layers rigid or semi-rigid materials, fillers or extenders and or multiple dampening layers that could be viscoelastic, elastic or non-viscoelastic materials with or without mineral or manmade fibers, fillers or extenders and can be added to or sandwiched into the present invention thus forming multiple decoupling layers, multiple barrier layers and multiple dampening layers. It is obvious to those adept in the industry that since the construction of the disclosed embodiments using one decoupling layer 1 , one barrier layer 3 and one dampening layer 4 exceeds the International Building Code minimum requirement of a 50 Impact Insulation Class and 50 minimum Sound Transmission Class rating, that adding more layers, or using multiple layers of any or all components or by adding extenders or fillers would only enhance the sound reduction properties of the material.
In a fifth specific embodiment alternate materials can be used for layer 5 to prevent the roll from sticking to itself if the material is wound into a roll or stacked on top of itself. Alternate materials for layer 5 include but are not limited to sand, limestone, talc, fly ash, mineral particles, granules, glass spheres and or ceramic nano-particles alone or in combination. This is obvious to those adept in the industry. Also a film or paper or chemical or nonchemical treatment could be used as a separation layer or means to prevent the material from bonding or sticking to itself and can be used instead of the release liner 5 . It is also obvious to those adept in the industry that an adhesive can be used in situ to bond the membrane to the floor, wall or ceiling or other substrates.
In a sixth specific embodiment the barrier layer 3 is removed and replaced by using a heat, chemical, material and or other treatment such as a nip or calendar roll on the surface of the decoupling layer 1 . Other techniques to maintain the separation of the dampening layer 4 from the decoupling layer 1 are obvious to those adept in the industry. This is another method to achieve the effective decoupling properties of the present invention and is obvious to anyone adept in the field.
The sound barrier membrane is typically created by: (1) selecting a material for the decoupling layer; (2) selecting a material for the barrier layer; (3) selecting a material for the dampening layer; (4) bonding the decoupling layer to the barrier layer; and (5) bonding the barrier layer to the dampening layer. This is typically performed in a factory and sent to a site for sale or installation.
In another embodiment of the method for assembly of the sound barrier membrane, the dampening layer 4 is not factory applied to the barrier layer 3 during manufacturing. The decoupling layer 1 is bonded to a barrier layer 3 using an adhesive layer 2 during manufacturing process but the dampening layer 4 is applied in the field as a separate layer during installation. This dampening layer 4 can be a membrane or any material that acts as a dampening layer 4 such as cork, rubber, tire rubber, silicone caulk, asphalt, rubber compound, modified bitumen compound, urethane, silicone, polypropylene or other foams alone or in combinations. This dampening layer 4 is bonded to the substrate, floor, wall or other structure using any technique known in the industry such as using a glue, caulk, asphalt, compound or modified bitumen compound or adhesive. The barrier layer 3 is then bonded to the dampening layer 4 . The barrier layer 3 can be bonded to the dampening layer 4 using glue that can acts as a dampening layer 4 such as a urethane or silicone adhesive, caulk or paste.
In another specific embodiment all of the layers shown in FIG. 2 (the decoupling layer 1 , the adhesive layer 2 , the barrier layer 3 and the dampening layer 4 ) can be sold individually or in kits of various combinations and combined in the field. The decoupling layer 1 can be sold separately or with a glue or other combination of materials and can be bonded to a barrier layer 3 using the adhesive in the kit or any glue, welding or fastening technique known in the industry such as hook and loop material, hot glue, double sided tape, or other techniques known in the industry. The dampening layer 4 does not have to be factory applied but can be field applied to the barrier layer 3 using glue that acts as a viscoelastic, elastic or dampening layer 4 such as a urethane or silicone adhesive that is itself a viscoelastic, elastic or dampening material. A viscoelastic, elastic or dampening material including modified bitumen, rubber, recycled tire rubber, cork, or other material, can be bonded using any glue, adhesive. Other techniques for bonding include: mopping or head welding applying asphalt or modified bitumen, cold welding, UV curing, using double sided adhesive tapes, pressure sensitive adhesives, contact adhesives, caulk, paste or other adhesives like urethane, silicone, epoxy, or starch based glues. All of the above techniques and materials allow the creation of this embodiment in pieces or layers. This also allows the creation of the embodiments disclosed by the addition of one or parts of the above to existing sound reduction membranes, panels or system like sound channel panels, rods, strips, and or blocks to name a few.
The embodiments disclosed can also be used in roofing, walls, buildings, appliances, aircraft, automotive, naval, and/or other sound reducing applications.
The above is a detailed description of particular embodiments of the invention. It is recognized that departures from the disclosed embodiments may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. Those skilled in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed herein and still obtain a like or similar result without departing from the spirit and scope of the invention. All of the embodiments disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. | A sound barrier membrane comprises of a decoupling layer, a barrier layer and a dampening layer. The membrane also provides crack isolation, and acts as a vapor barrier. Numerous materials are disclosed which can be used to create these layers. Methods for assembly of the sound barrier membrane are also disclosed. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Application No. PCT/FR2012/050058, filed on Jan. 10, 2012, which claims the benefit of FR 11/50297, filed on Jan. 14, 2011. The disclosures of the above applications are incorporated herein by reference.
FIELD
[0002] The present disclosure relates to a thrust reverser for a turbojet engine, and a door for such a thrust reverser of an aircraft nacelle.
BACKGROUND
[0003] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
[0004] An aircraft is driven by several turbojet engines each accommodated in a nacelle also harboring a set of ancillary actuation devices related to its operation and ensuring various functions when the turbojet engine is operating or at a standstill. These ancillary actuation devices notably comprise a mechanical system for actuating a thrust reverser.
[0005] A nacelle generally has a tubular structure along a longitudinal axis comprising an air intake upstream from the turbojet engine, a middle section intended to surround a fan of the turbojet engine, a downstream section harboring thrust reversal means and intended to surround the combustion chamber of the turbojet engine. The tubular structure generally ends with an ejection nozzle, the outlet of which is located downstream from the turbojet engine.
[0006] Modern nacelles are intended to harbor a dual flux turbojet engine capable of generating via rotating blades of the fan a hot air flow (also called a “primary flow”) stemming from the combustion chamber of a turbojet engine, and a cold air flow (“secondary flow”) which circulates outside the turbojet engine through a ring-shaped passage also called an “annular vein”.
[0007] By the term of “downstream” is meant the direction corresponding to the direction of the cold air flow penetrating the turbojet engine. The term of “upstream” designates the opposite direction.
[0008] The annular vein is formed in the downstream section by an external structure called an outer fixed structure (OFS) and an internal concentric structure called an inner fixed structure (IFS) surrounding the structure of the engine strictly speaking downstream from the fan. The internal and external structures belong to the downstream section. The external structure may include one or several rotationally mobile doors so as to be capable, under the action of driving means, of switching between an inactive closed position during the operation of the turbojet engine, a so called “direct thrust” mode, in which the doors form a portion of the downstream section, and a reversal position or open position in which they switch so that a downstream portion of each door will at least partly obturate the conduit of the nacelle and an upstream portion in the downstream section opens a passage allowing the airflow to be radially channeled relatively to a longitudinal axis of the nacelle.
[0009] In order to be able to improve the reorientation of the air flow in a direction tending as close as possible towards a longitudinal direction of the nacelle, some doors have been equipped with terminal spoilers, also called baffles, forming upstream from the door a return element substantially perpendicular to the plane formed by the latter. Thus, when the door is in the thrust reversal position, the spoiler is orientated in a direction substantially longitudinal to the nacelle and forces the air flow in this direction.
[0010] When the door is in the closed position, each spoiler is orientated along a direction substantially perpendicular to the longitudinal axis of the nacelle and penetrates the air flow circulation vein. There is the risk that the spoiler will then block the air flow circulating in the direct thrust mode, which is not permissible.
[0011] In order to overcome this drawback, doors have been designed so as to have an upstream cavity at an internal surface of said door. Consequently, the door has reduced thickness upstream which allows both the spoiler to protrude from said door and not to have a length greater than the thickness of the nacelle upstream from the door in order not to penetrate the annular circulation vein of the air flow when the door is in the closed position.
[0012] However, such a cavity forms a significant aerodynamic hindrance inside the annular air flow vein when the door is in the closed position, which reduces the overall performances of the turbojet engine.
[0013] Rotationally mobile spoilers along a plane perpendicular to the plane of the door, called a “deflection plane”, are known from application FR 2916484.
[0014] In spite of the advantages provided by the operation of such spoilers, it may prove to be of interest to increase the front surface area of each spoiler in contact with the deflected air flow in order to improve the orientation of the whole of the deflected air flow.
SUMMARY
[0015] According to a first aspect of the present disclosure, a door for a thrust reverser of an aircraft nacelle is capable of being pivotally mounted on a fixed structure of the nacelle comprising an internal surface designed in order to be integrated to an annular circulation vein of an airflow and an external surface designed for ensuring the outer aerodynamic continuity of the nacelle intended to be equipped with said thrust reverser.
[0016] The door is equipped with means for deflecting the air flow positioned at an upstream end of the door and moveably mounted in a deflection plane substantially perpendicular to the plane of the door between a first retracted position in which the deflection means do not penetrate the annular vein when the door is in the closed position, and a second deployed position in which the deflection means will protrude from the door when the door is in the open position, each deflection means being associated at its ends with an articulation arm rotationally mobile about a pivot axis substantially perpendicular to the deflection plane allowing rectilinear displacement of said deflection means in the deflection plane upon passing from the retracted position to the deployed position.
[0017] Thus, by means of the articulation arm, the deflection means are set into motion according to a substantially rectilinear displacement in the deflection plane. The door of the present disclosure thus has a deflection system which is simple to install, not cumbersome and reliable to use.
[0018] Further, the rectilinear displacement of the deflection means allows the totality of the surface area of the deflection means to be able to be in contact with the deflected air flow. Therefore, by means of the door of the present disclosure, the size of the deflection means may be optimized according to the desired size of the surface area in contact with the deflected air flow.
[0019] Further, advantageously, the adjustment of the kinematics of the deflection means may be simply achieved by adjusting the kinematics of the articulation arms.
[0020] It is also possible to absorb the load of the aerodynamic forces of the deflection means with the articulation arms without resorting to additional devices of the slider or friction shoe type.
[0021] Finally, it is possible to contemplate synchronization of the whole of the deflection means when said means attain the deployed position.
[0022] According to other features of the present disclosure, the door includes one or several of the following optional features considered alone or according to all possible combinations:
[0023] the deflection means each comprise an abutment means positioned at one end of each deflection means so as to block the position of the deflection means in the deployed position with which it is possible to limit the deployment of the deflection means and avoid damaging the neighboring ends of two deflection means;
[0024] the articulation arms include at each end at least one elastic return means, notably as a coil spring, giving the possibility of switching from the retracted position to the deployed position, which gives the possibility in a simple and efficient way of ensuring the return to the deployed position when the nacelle receiving the door of the present disclosure is in the thrust reversal position;
[0025] the door comprises a door actuator allowing the door to pass from the open position to the closed position, said actuator being positioned so as to receive and block the adjacent ends of two deflection means in the retracted position, which allows saving of space and mass while allowing efficient retention of the deflection means in the retracted position;
[0026] the deflection means comprise at least two spoilers or two flaps mounted on either side of a median axis of the door.
[0027] According to another aspect, the present disclosure illustrates a thrust reversal system comprising at least one door and a fixed structure on which said door is pivotally mounted between a closed position in which it closes the thrust reverser and forms a portion of an external cowling, the means for deflecting the flow being in a retracted position, and an open position in which it clears a passage in the fixed structure so as to deflect said one air flow, the deflection means being in a deployed position.
[0028] In one form, the thrust reverser system according to the present disclosure comprises abutment means attached onto the fixed structure so as to receive and block the adjacent ends of two deflection means in the retracted position which gives the possibility in a simple and not very cumbersome way of blocking the deflection means in the retracted position.
[0029] The present disclosure also addresses a nacelle for a turbojet engine comprising at least one thrust reverser system.
[0030] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
[0031] In order that the present disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:
[0032] FIG. 1 is a partly schematic sectional view of a form of a nacelle of the present disclosure;
[0033] FIGS. 2 and 3 are partial schematic cross-sectional views of a door of a thrust reverser according to the present disclosure in a respectively closed and open position;
[0034] FIG. 4 is a partial and schematic perspective view of a door of the present disclosure in the open position (further called <<thrust reversal>> position) mounted on a nacelle corresponding to the form of FIG. 1 ;
[0035] FIG. 5 is a schematic and partial front view of a door used in the form of FIG. 4 with deflection means in the retracted position; and
[0036] FIG. 6 is a schematic and partial front view of a door used in the form of FIG. 4 with deflection means in the deployed position.
[0037] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
DETAILED DESCRIPTION
[0038] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
[0039] As illustrated in FIG. 1 , a nacelle 1 according to the present disclosure has a substantially tubular shape along a longitudinal axis Δ. The nacelle of the present disclosure 1 comprises an upstream section 2 with an air intake lip 13 forming an air intake 3 , a middle section 4 surrounding a fan 5 of a turbojet engine 6 and a downstream section 7 . The downstream section 7 comprises an internal structure 8 (generally called an <<IFS>>) surrounding the upstream portion of the turbojet engine 6 , an external structure (OFS) 9 supporting a moveable cowl (not shown) including thrust reversal means.
[0040] The IFS 8 and the OFS 9 delimit an annular vein 10 allowing circulation of an air flow 12 penetrating the nacelle 1 of the present disclosure at the air intake 3 .
[0041] The nacelle 1 of the present disclosure ends with an ejection nozzle 21 comprising an external module 22 and an internal module 24 . The internal 24 and external 22 modules define a channel for the stream of a hot air flow 25 emerging from the turbojet engine 6 .
[0042] According to the form illustrated in FIGS. 2 and 3 , a door thrust reverser includes doors equipped with a deflection means in the form of a spoiler. In an alternative, the deflection means may be in the form of a plurality of flaps. A flap is distinguished from a spoiler by the fact that it has a lower tilted portion relatively to a planar upper portion, said lower portion also having curvature aiming at optimizing the reorientation of the inverted air flow.
[0043] The thrust inverter with spoiler doors typically comprises three main portions, i.e. a fixed portion in the form of an upper panel 30 located upstream in the OFS 9 , a moveable portion 32 downstream from the upstream panel 30 and a fixed downstream ferrule 33 . The fixed portion 30 comprises an external panel 34 ensuring aerodynamic continuity of the external surface of the nacelle 1 , and an internal panel 35 forming an external panel of the annular vein 10 . The external 34 and internal 35 panels are connected through a front frame 37 which also ensures support of the means for controlling the moveable portion 32 , formed in this case by an actuator 38 .
[0044] The moveable portion 32 typically includes one or several displaceable elements commonly called doors 39 . Each door 39 is pivotally mounted about an axis of rotation substantially co-linear with the plane formed by each door 39 and substantially perpendicular to the longitudinal axis Δ of the nacelle of the present disclosure.
[0045] Consequently, under the action of the control means 38 , each door 39 may switch between a position in which it ensures the structural continuity between the upstream panel 30 and the downstream ferrule 33 and an open position in which said door 39 clears a passage between the upstream panel 30 and the downstream ferrule 33 allowing the air flow to escape through said opening.
[0046] As illustrated in FIG. 3 , during this pivoting, a downstream portion of the door 32 a will at least partly block the annular vein 10 thereby forcing the flow to circulate through the cleared opening.
[0047] From a structural point of view, the door 39 comprises an external panel 40 which will, in the direct thrust mode, be placed in the extension of the external panel of the fixed upstream panel 30 and ensure outer aerodynamic continuity with an external panel 45 of the rear portion (see FIG. 2 ), on the one hand and, an internal panel 41 and an upstream frame 42 connecting the external panel 40 and the internal panel 41 on the other hand.
[0048] The upstream frame 42 is extended at the upstream end with deflection means 43 intended, when the door 39 is open, for reorienting a portion of the air flow towards the front of the nacelle thereby generating a counter-thrust.
[0049] To do this, the deflection means 43 are in a deflection plane substantially perpendicular to the plane of the door between a first refracted position in which the deflection means 43 do not penetrate the annular vein 10 when the door 39 is in a closed position and a second deployed position in which the deflection means 43 will protrude from the door 39 .
[0050] The deflection means 43 may comprise at least two deflection means 43 a and 43 b mounted on either side of a median axis Δm of the door 39 .
[0051] As illustrated in FIGS. 4 to 6 , each deflection means 43 a, 43 b is associated at its ends 51 a, 51 b, 53 a and 53 b with an articulation arm 61 a, 61 b, 63 a and 63 b rotationally mobile about a pivot axis substantially perpendicular to the deflection plane allowing rectilinear displacement of said deflection means 43 a, 43 b in the deflection plane upon switching from the retracted position to the deployed position.
[0052] Thus, by means of the articulation arm 61 a, 61 b, 63 a and 63 b, the deflection means 43 a, 43 b are set into motion according to a substantially rectilinear displacement in the deflection plane. The door of the present disclosure 39 thus has a deflection system which is simple to install, not cumbersome and reliable to use.
[0053] Further, the rectilinear displacement of the deflection means 43 a, 43 b allows the totality of the surface area of the deflection means 43 a, 43 b to be able to be in contact with the deflected air flow. Therefore, by the door of the present disclosure 39 , the size of the deflection means 43 a, 43 b may be optimized depending on the desired size of the surface area in contact with the deflected air flow.
[0054] Advantageously, the adjustment of the kinematics of the deflection means 43 a, 43 b may be simply achieved by adjustment of the kinematics of the articulation arms 61 a, 61 b, 63 a and 63 b.
[0055] It is also possible to absorb the load of the aerodynamic forces of the deflection means 43 a, 43 b with the articulation arms 61 a, 61 b, 63 a and 63 b without resorting to additional devices of the slider or friction shoe type.
[0056] Finally, it is possible to contemplate synchronization of the whole of the deflection means 43 a, 43 b when said means attain the deployed position.
[0057] As illustrated in FIG. 6 , the deflection means 43 a and 43 b may each comprise an abutment means 60 a and 60 b positioned at one end 53 a and 53 b of each deflection means so as to block the position of the deflection means 43 a, 43 b in a deployed position which gives the possibility of limiting the deployment of the deflection means 43 a, 43 b and avoiding damage to the neighboring ends of two deflection means 43 a, 43 b. The abutment means 60 a and 60 b may have a substantially V-shape which advantageously makes it possible to synchronize the deflection means 43 a, 43 b and guarantee symmetry of the trajectory of said means 43 a, 43 b.
[0058] The articulation arms 61 a, 61 b, 63 a and 63 b are attached both onto the door 39 and to each end of a deflection means 43 a, 43 b. The arms 61 a, 61 b, 63 a and 63 b may have a length adapted according to the desired travel followed by each deflection means 43 a and 43 b. In the case of the form of FIG. 2 , the articulation arms 61 a and 63 a have a length which increases with the width of the deflection means 43 a and 43 b, in other words with the increase of the surface area in contact with the air flow. Thus, each fixed articulation arm 61 b and 63 b in proximity to the median axis Δm of the door 39 has a greater length than the articulation arms 61 a and 63 a attached at a distance from said median axis Δm.
[0059] It is thus possible to increase and decrease the surface area in contact with the air flow by modifying the length of each articulation arm 61 a, 61 b, 63 a and 63 b.
[0060] The articulation arms 61 a, 61 b, 63 a and 63 b may include at each end at least one elastic return means, notably in the form of a coil spring, with which it is possible to pass from the retracted position to the deployed position which gives the possibility of ensuring in a simple and efficient way the return to the deployed position when the nacelle 1 of the present disclosure receiving the door 39 is in the thrust reversal position. An articulation arm 61 a, 61 b, 63 a and 63 b may thus include at each end, a plurality of coil springs which allows operation of the articulation arms 61 a, 61 b, 63 a and 63 b even when a spring malfunctions or no longer operates.
[0061] The door actuator 38 allowing the door to pass from the open position to the closed position, may be positioned so as to receive and block one of the ends 61 b and 63 b of two deflection means 43 a, 43 b in a retracted position, which allows saving of space and mass while allowing efficient retention of said deflection means 43 a and 43 b. The ends may be adjacent and in proximity to the median axis Δm.
[0062] In an alternative, the OFS 9 , notably the upstream frame 32 , may comprise abutment means so as to receive and block one of the ends of the two deflection means 43 a, 43 b in the retracted position, notably adjacent ends.
[0063] Although the present disclosure has been described in connection with particular exemplary forms, it is quite obvious that it is by no means limited thereto and that it comprises all the technical equivalents of the means described as well as their combinations if the latter enter the scope of the present disclosure. | A door for a thrust reverser of a nacelle of an aircraft being pivotally amounted on a fixed structure of the nacelle, in particular, the door being fitted with deflectors deflecting air flow is disclosed. The deflectors are arranged at an upstream end of the door and mounted such that they can move in a deflection plane perpendicular to the plane of the door. Each deflector is associated at its ends with an articulation arm capable of rotating about a pivot axis perpendicular to the deflection plane, allowing the deflectors to move in a straight line in the deflection plane. The present disclosure also relates to a thrust reverser system including the door and a fixed structure on which the door is pivotally mounted between a closing position and an open position. | 5 |
BACKGROUND OF THE INVENTION
[0001] This invention relates to mine ventilation structures, such as mine undercasts and mine overcasts of the type shown in U.S. Pat. No. 5,466,187 issued Nov. 14, 1995 to John M. Kennedy and William R. Kennedy, entitled Mine Ventilation Structure, which is incorporated herein by reference.
[0002] Reference may be made to said U.S. Pat. No. 5,466,187 for background on mine overcasts (including their function and prior overcast structures), and to the book titled “Practical Mine Ventilation” by William C. Kennedy, published by Intertec Publishing Corporation, for background on mine ventilation structures in general. This book is also incorporated by reference.
SUMMARY OF THE INVENTION
[0003] The invention is especially concerned with improvement in the decking of a mine ventilation structure such as the mine overcast disclosed in said U.S. Pat. No. 5,466,187, among the several objects of the invention being noted the provision of a deck made up of panels of relatively lighter weight and of equal or even greater strength for their lighter weight than the panels shown in U.S. Pat. No. 5,466,187, the lighter weight making them more readily transportable; the provision of such a deck which is structurally efficient, having superior beam strength and having a surface characteristic enabling walking thereon; the provision of such a deck with the feature of interconnection of the panels for transfer of weight from one panel to an adjacent panel or panels; the provision of such a deck with the feature of panel edge support; and the provision of an improved panel for use in making the aforementioned deck.
[0004] In general, a mine ventilation structure of this invention comprises a deck which includes a plurality of elongate sheet metal panels, each panel being generally of modified inverted channel shape in transverse cross-section having a web at the top and side flanges extending down vertically from opposite sides of the web. The web is modified so as to have a flat horizontal area and an indentation extending down from the flat area between the side flanges lengthwise of the panel. The panels extend in side-by-side relation with the flanges of adjacent panels substantially contiguous one with another and the flat horizontal areas of the panels in generally coplanar relation forming a walking surface. The indentation in each panel is of such depth that the neutral axis of the panel is in the lower two-thirds of the panel depth.
[0005] The present invention is also directed to a plurality of elongate deck panels of the type described above for use in constructing a mine ventilation structure, such as a mine overcast or undercast.
[0006] Other objects and features will be in part apparent and in part pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] [0007]FIG. 1 is a top plan of an overcast structure of the invention, parts being broken away;
[0008] [0008]FIG. 2 is a vertical section taken generally on line 2 - 2 of FIG. 1 on a larger scale than FIG. 1;
[0009] [0009]FIG. 3 is an enlarged fragment of FIG. 2 showing one of the deck panels in transverse section with the neutral axis of the panel indicated in phantom; and
[0010] [0010]FIG. 4 is a view like FIG. 3 illustrating a deck panel such as shown in U.S. Pat. No. 5,466,187 with the neutral axis thereof shown in phantom, for comparison with FIG. 3.
[0011] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0012] Referring first to FIG. 1 of the drawings, a mine overcast of this invention, designated in its entirety by the reference numeral 1 , is shown to comprise a tunnel-forming structure having generally parallel spaced-apart side walls each designated 3 and a deck designated in its entirety by the reference numeral 5 spanning the side walls constituting the roof of the tunnel and the floor of a passage over the tunnel. The overcast is installed at the intersection of two passageways P 1 , P 2 in a mine to maintain the air flowing through the two passageways separate. (In the embodiment shown in FIG. 1, the airflow in passageway P 1 passes through the overcast 1 and the airflow in passageway P 2 passes over the overcast.)
[0013] The deck 5 of the overcast 1 comprises a plurality of elongate sheet metal panels 7 (eight being shown by way of example) extending between (bridging) the side walls 3 . To this extent, the overcast corresponds to that disclosed in U.S. Pat. No. 5,466,187 and reference may be made thereto for detail, but it differs therefrom in that each panel 7 (preferably made of sheet metal) is modified with respect to the cross-section of each panel making up the deck of U.S. Pat. No. 5,466,187 (one of which is illustrated in FIG. 4 side-by-side with FIG. 3 for comparison).
[0014] Thus, each panel 7 is generally of modified inverted channel shape in transverse cross-section, having a web 9 at the top and flanges 11 extending down vertically from opposite sides of the web, the flanges having inwardly turned lips 13 with upturned free edges 15 . The web 9 is modified with respect to the web of the panel of U.S. Pat. No. 5,466,187 so as to have side portions 17 presenting a generally flat horizontal area and an indentation, generally designated 19 , extending down from the flat area between the side walls lengthwise of the panel 7 (i.e. between side portions 17 ). The panels 7 extend between the tunnel side walls 3 in side-by-side relation with the flanges 11 of adjacent panels substantially contiguous one with another and the flat horizontal areas presented by web side portions 17 in generally coplanar relation forming a walking surface. Tie bars 21 and wire ties 23 may be used as in U.S. Pat. No. 5,466,187 to secure the panels 7 in place. The indentation 19 in each panel 7 is of such depth D that the neutral axis N (see FIG. 3) of the panel 7 is preferably in the lower two-thirds of the panel depth D (the width of each of flanges 11 , which is the depth of each flange in the horizontal disposition of the panel). In the particular embodiment shown in FIG. 3 the neutral axis N is at approximately the one-half panel depth level. Thus, the neutral axis N is lower than the neutral axis Na of the panel 7 a of U.S. Pat. No. 5,466,187 (compare FIGS. 3 and 4). This is brought about by the indenting of the web 9 bringing sheet metal down from the web as shown.
[0015] Bringing the neutral axis N down as above noted enables reduction in the gauge of the sheet metal making up a panel 7 and thus a reduction in the weight of the panel without detracting from the strength of the panel acting as a beam. The strength is a function of the section modulus which is defined by the moment of inertia of the cross-sectional area divided by the greatest distance from an “extreme fiber” to the neutral axis. Thus, by bringing the neutral axis N down to the level shown, the distance from the lips 13 (formerly the “extreme fiber”) to the neutral axis is lessened and the moment of inertia divided by this smaller distance (the section modulus) is increased.
[0016] The decrease in the gauge of the sheet metal used is more than enough to offset the increase in cross-sectional area of a panel 7 brought about by the indentation 19 . For example, panel 7 may be made of 14 gauge (0.079 in.) sheet steel with a cross-sectional area of 4.144 in 2 and with a section modulus of 7.726 in 3 , as contrasted with a 5,466,187 panel 7 a of 14 gauge (0.079 in.) sheet steel with a cross-sectional area of 3.503 in 2 having a section modulus of 5.39 in 3 . Thus panel 7 is significantly stronger than the prior design, which permits the panel to be made of lighter gauge material with attendant reduction in material cost. Using one calculation, for example, a panel 7 of the present invention made of sheet steel having a thickness of 0.055 in. and a cross sectional area of 2.884 in 2 would have about the same section modulus (5.399 in 3 ) as the prior panel 7 a described above, yet it would use only about 82% (2.884/3.503) of the material.
[0017] The indentation 19 is generally for the full depth of panel 7 . Preferably, it is generally V-shaped with inclined side walls 19 a and a flat bottom 19 b generally in the horizontal plane of the lower edges of flanges 11 (i.e. of lips 13 ). However, it will be understood that the indentation can have other suitable shapes (e.g., U) without departing from the scope of this invention.
[0018] The improved deck panels of this invention can be used to construct other types of mine structures, such as mine undercasts, bridge crossings (sometimes referred to as “bridgecasts”), and belt crossings.
[0019] In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
[0020] As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
[0021] When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. | A mine ventilation structure with a deck made up of panels of inverted channel shape modified to be of relatively light weight yet strong. | 4 |
This application is a U.S. national stage application of PCT international application PCT/GB08/02625, filed on Aug. 1, 2008, which claims priority to United Kingdom Patent Application No. 0715171.5, filed on Aug. 3, 2007.
FIELD OF INVENTION
The present invention relates to a device for handling samples, in particular clinical samples in preparation for analysis, for instance by means of a nucleic acid amplification method, in particular the polymerase chain reaction (PCR), as well as novel elements and procedures which may be utilised in such devices.
BACKGROUND OF INVENTION
The analysis of fluid samples, for example clinical or environmental samples, may be conducted for several reasons. One current area of interest is the development of a method for positively identifying biological material in a fluid sample, for example a clinical or environmental sample. Such a method would allow for early diagnosis of disease states, which in turn would enable rapid treatment and infection control, or the identification of environmental contaminants and the like. There are many techniques by which very sensitive analysis of samples can be carried out including for example nucleic acid amplification techniques such as the polymerase chain reaction (PCR).
However, the very sensitivity of these techniques mean that they are subject to problems with contamination, as even small amounts of contaminants can mask or give false positive results.
In general, the analysis of clinical or environmental samples is carried out in laboratories or in mobile equipment or analytical devices which may be some distance from the site of collection of the sample. This means that samples need to be collected for example by an operative, and placed in a sealed sample vessel for transport to the analytical device. Once delivered to the analytical device, for example, in a laboratory, the sample vessel is usually opened by a further operator, and the contents removed, for example using a pipette which may be carried out manually or by machine, and placed in a reaction chamber to allow analysis to occur. There is a greater risk that contamination may occur at this stage, in particular since a laboratory or analytical environment is most likely to be contaminated by the target analyte, for example the target nucleic acid.
SUMMARY OF THE INVENTION
According to the present invention there is provided a system for delivering a sample, said system comprising
(i) a cartridge comprising a body section adapted to hold a sealed sample vessel so as to fix the position of a seal of the sample vessel in relation to the cartridge; and (ii) apparatus adapted to receive said cartridge, said apparatus being provided with an opening system for opening a sealed sample vessel contained within the cartridge.
By ensuring that the seal of a sample vessel is only broken once the sample vessel is contained within the apparatus, the risk of contamination from an operator or from the surroundings in the laboratory or in the area of the analytical device is reduced. The breaking of the seal can be accomplished automatically by the operation of the apparatus. The use of a cartridge to precisely position the seal of the sample vessel means that the opening system of the apparatus is able to accurately and effectively interact with it.
The sealed sample vessel may be supported in the body section of the cartridge directly, but in a preferred embodiment, a holder is provided, which can accommodate the sample vessel, and it is then the holder which is insertable into the body section.
The holder is suitably specifically shaped to accommodate the sample vessel. In particular, it may be shaped so that the sample vessel itself is substantially enclosed within the holder. The holder, and preferably the entire cartridge is suitably made from a rigid and durable material such as rigid polymer. When such a material is used to substantially enclose a sample vessel, it provides a further degree protection against accidental breach of the sample vessel, which may be important where this is of a relatively fragile or brittle material such as glass.
Suitably the seal of the sample vessel comprises a plastics or rubber cap, which is preferably held in position by a locking action or screw thread so that it is not easily dislodged. In a particular embodiment, the cap has a piercable membrane such as a rubber membrane or a laminated metal foil in an upper surface of the cap, to facilitate opening once inside the apparatus.
In a particular embodiment, the sample vessel comprises a sealable tube. The dimensions of the tube are suitably such that it may accommodate not only liquid samples of the desired volume, but also if required, swabs.
In this case, the holder is also generally tubular in shape, but with a slightly larger diameter than that of the tube and so that it may fit snugly within the holder. In a particular embodiment, when the tube is sealed with a cap, the diameter of the cap is greater than that of the tube, and also of the internal diameter of the holder, so that, when in position in the holder, the cap rests on the top of the holder. This allows for accurate positioning of the tube within the holder and thus within the cartridge.
A swab support with a swab attached may be integral with the cap of a tube of this type. In this embodiment, in use the cap may be removed for a swab sample to be taken. The swab is then returned to the tube together with sufficient transport medium, or diluent such as sterile water or elution buffer to immerse the swab sample in the tube. The cap is then secured. The swab will generally remain immersed in liquid at this time. Simple shaking of the sealed tube will ensure that at least some sample material is transferred from the swab into the liquid.
Alternatively the swab may be provided as a separate component as part of a sampling kit. These are available with a plastics snap-off feature enabling the swab section to be conveniently separated from the handle section. The shorter, snapped off swab section may then be transferred into the foiled tube containing the transport medium, diluent or elution buffer and treated as above.
Suitably, the holder is integral with or may otherwise be retained within suitable retaining elements on the body of the cartridge in a sample vessel receiving position, in which a sealed sample vessel can be readily inserted into it. However, it should be moveable with respect to the body from a sample vessel receiving position to a closed position in which the desired position of the seal of the sample vessel in relation to the cartridge is achieved. For example, the holder may be pivotal between a sample vessel receiving position and a closed position, or it may be simply lifted manually from the retaining elements on the body and inserted into, for example a suitable recess such as an aperture or channel within the body section of the cartridge, which forms the closed position.
In a particular embodiment, the sample vessel is fixable in the closed position by means of a locking mechanism, such as a snap fit tongue or flange, fitted onto a holder where present, and arranged to engage in a slot provided in the body section of the cartridge.
Suitably, once in the closed position, the seal of the sample vessel is covered and is suitably substantially completely enclosed by the cartridge, holder and/or locking mechanism and so is no longer accessible for removal or breach by an operator. Thus in a particularly preferred embodiment, the locking mechanism, such as the snap fit tongue or flange effectively covers the seal of the reaction vessel once in the closed position, so that it is effectively substantially enclosed by the body section and the tongue or flange.
The locking mechanism is suitably arranged so that it will not operate until the sample vessel is correctly inserted into the holder, where present. This ensures that the seal of the sample vessel is accurately and reliably positioned within the cartridge.
The opening system may take various forms depending upon the nature for example of the sealed sample vessel and the configuration of the apparatus for example. In particular, the opening system provides a means for breaching the seal of the sealed sample vessel, for example by removal or breach of a cap of the sealed sample vessel. In a particular embodiment, the opener comprises an actuator for moving the sample vessel, for example within the holder so as to force the seal of the sealed reaction vessel into piercing contact with a piercing element.
For example, the piercing element may be a needle and piercing of the seal by the needle is facilitated in this case if the seal comprises a piercable membrane as discussed above. In a preferred embodiment, the piercing element comprises a plastics hypodermic needle-shaped tube formed in a recess with an annular seal that interfaces with the face or outside of the sample tube so as to prevent unwanted leakage of the sample material.
Once opened within the apparatus, the sample may be subject to chemical, physical, biochemical, analytical or assay procedures as required. At least some of these may be carried out in the sample vessel itself, but more usually, the sample will be transferred to one or more reaction chambers for further processing. In this case, a delivery device for delivering a liquid sample contained within the sample vessel to a reaction chamber is suitably provided.
The reaction chamber may be provided in the apparatus or it may be contained on the cartridge, depending upon the configuration of the apparatus and the cartridge.
Similarly, the delivery device may be integral with the apparatus or the cartridge, depending upon the nature of the opening system.
In a particular embodiment, both the reaction chamber and the delivery device are contained on the cartridge, so that at least the first subsequent processing steps are conducted on the cartridge.
In a particular embodiment, a piercing needle or piercing element which either forms part of the opening system of the apparatus or, where provided in the cartridge, acts in conjunction with the opening system of the apparatus to breach the seal, forms the delivery device. The piercing needle or piercing element used comprises an internal channel and the end of the needle or piercing element remote from the piercing end is positioned in the reaction chamber. In this way, when the piercing needle or piercing element enters the sample vessel, liquid sample may flow directly out through the same needle or piercing element into the reaction chamber, so ensuring that the sample is enclosed and protected from contamination from the surroundings for as long as possible. A second needle or piercing element, situated above the first, may be employed in parallel where the second needle or piercing element allows the passage of air to displace the liquid drained from the sample tube.
The liquid sample may be drawn along the delivery device such as the piercing needle or piercing element for instance using a reduced pressure or vacuum. However, preferably the cartridge and the apparatus are configured so that when a sample vessel is in position within the cartridge and the cartridge is in position within the apparatus, the sample vessel is inclined with the piercable end lower than the base of the tube so that the liquid flows under the action of gravity out through the delivery device.
Suitably, the delivery device is arranged to ensure that a predetermined volume of sample is delivered to the reaction chamber. This may be achieved by the incorporation of liquid measurement devices within or associated with the delivery device. However, when the delivery device comprises a gravity fed piercing needle or piercing element as described above, a predetermined sample volume can be delivered by ensuring that the volume of liquid placed in the sample vessel during the collection stage is constant (within a set range), and then ensuring that the needle or piercing element enters the sample vessel such that an open end is in a predetermined and appropriate relationship to the meniscus of the liquid within the sample vessel.
In a particular embodiment, both the delivery device, such as the piercing needle or piercing element, and the reaction chamber are contained within the cartridge. In this arrangement, care needs to be taken to ensure that a sealed sample vessel may not inadvertently come into seal-breaching contact with an element of the opening system such as the piercing needle or piercing element prior to the initiation of the opening system within the apparatus. This may be done by using a holder for the sealed sample vessel and ensuring that the actuator is of a relatively small cross sectional area, and the holder is provided with an opening of a size which is sufficient to allow access to the actuator only. In this way, an operator's fingers for example, may be excluded from the inside of the holder so that inadvertent movement of the sample vessel within the holder may be avoided. Suitably also the sample vessel fits into the holder in a snug manner, so that movement with respect to the holder and towards any piercing needle or piercing element can only take place under the action of direct pressure from the actuator. Furthermore, the nature of the seal, for example the thickness of the rubber membrane is selected so that it is only piercable by the needle or piercing element when a significant amount of direct pressure, such as that supplied by the actuator of the apparatus, is applied.
The apparatus suitably contains further elements which allow the analysis or further investigation of the sample to be continued. Thus it may for example include elements suitable for carrying out a variety of chemical or biochemical reactions, analysis or assays on the sample. For instance, the apparatus may comprise a device which carries out sample preparation procedures to make samples such as clinical or environmental samples suitable for procedures such as immunoassays or nucleic acid amplification reactions. In particular the apparatus may contain all the elements required both to prepare the sample and to carry out the subsequent analysis. An example of apparatus of this type is contained for example in WO2005/019836 the content of which is incorporated herein by reference.
The cartridge also suitably contains further elements which are useful in the subsequent procedures to which the sample are required to be subjected.
Such further elements may include one or more reagent chambers for holding reagents or materials required to continue the analysis of the sample. These reagents or materials, which include wash solutions, diluents or buffers as well as reagents used in the subsequent procedure, are suitably predispensed into the reagent chambers.
Where this involves sample preparation, for example to extract nucleic acid from samples suspected of containing cells, such reagents may include lysis reagents for example chaotrophic salts, bacteriophage, enzymes which may lyophilised, detergents, antibiotics the like. Where the subsequent procedure involves sample analysis, other reagents such as dyes, antibodies, enzymes (including for example polymerase enzymes for PCR), buffers, salts such as magnesium salts, may be included in further reaction chambers on the cartridge. However, the range of possible reagents is very large and they will be selected on a “case-by-case” basis, depending on the nature of the chemical or biochemical reaction or analysis or assay to which the sample is subjected.
The reagents may be present in solid or liquid form. When they are predispensed in solid form, these may be as a solid powder, bead, capsule or pressed tablet form, or they may be adhered to magnetic particles or beads, such as silica beads as is well known in the art.
Reagent chambers containing predispensed reagents are suitably sealed for example using foil seals which may be piercable within the apparatus using cutters. These may be integral with the apparatus, but in a particularly preferred embodiment, a cutter is removeably housed in the cartridge, for example within an appropriately shaped recess or aperture in the body section, so that it is available for use in relation to the particular chemical or biochemical reaction, analysis or assay being carried out.
Other mechanical elements in addition to the cutter, in particular those which may be of a disposable nature, which are useful in or otherwise facilitate further chemical or biochemical reaction, physical processing, analysis or assay of the sample, may also be removeably housed on the cartridge. Such elements may include devices required to move samples, reagents or materials from one chamber to another, such as pipettors, magnets or sheaths therefore, as well as small devices such as filters, stoppers, mixers, caps etc. which may require to be introduced into chambers in the course of the chemical, biochemical or analytical procedures or assays.
Particular examples of suitable pipettors are described in WO 2007/028966 the contents of which are incorporated therein by reference, whereas examples of sheaths for magnets useful in transferring magnetic beads or particles and thus any reagents attached thereto are described for example in WO2005/019836.
If desired also, processing components such as heaters, sonicators etc. which may be required to treat reagents or reagent mixtures to ensure that they are in a desired physical state and any time during the procedure, may also be removeably housed on the cartridge.
Mechanical elements such as cutters, pipettors, magnets or sheaths therefore, as well as other sheaths as detailed more fully below, and processing components as described above, will collectively be referred to hereinafter as “moveable components”.
In such cases, the apparatus is provided with means for accessing these moveable components and for moving them as necessary so that they can fulfil the required function in the chemical, biochemical, analytical or assay procedure. In particular, the apparatus may comprise a moveable arm which is able to interact with any moveable component on the cartridge.
The moveable arm, which is for example, a robotic arm, is suitably provided with a grab device, so that it can pick up any moveable components housed on the cartridge and lift it up out of its associate recess or aperture. Suitable grab devices are known in the art. The may include forked elements which are arranged to removeably interact with appropriately positioned flanges on the moveable components, but may also comprise controllable grabbing arms, able to close around an exposed upper portion of one of the moveable components. Again, the moveable components may include particular adaptations such as flanges or recesses which are arranged to interact with grabbing arms to facilitate movement.
The apparatus is designed such that a moveable component held on the arm may be positioned above an appropriate reaction or reagent chamber within the cartridge. The arm may be moveable laterally as well as vertically in order to achieve this. However, in a particular embodiment, the arm itself is moveable only in a single dimension which is vertically, and a transport means for the cartridge is provided, suitably as part of the apparatus, so as to allow it to be moved in a lateral direction that the arm may be positioned directly above each element on the cartridge including reaction chambers, reagent chambers as well as moveable components, so as to allow the desired sequence of events to occur.
When electrically operated processing components such as a heater or sonicators are supplied in this way, it may be useful if the connection between the processing component and the arm of the apparatus were also to provide an electrical connection sufficient to provide power to the processing component during use. However, such elements may be more conveniently housed within the apparatus itself, and arranged to be delivered for example to the appropriate chamber on the cartridge at the required time. The arm itself or an adjunct to the arm on which the processing component such as the heater or sonicator is fitted, may be used in order to ensure that the component can be positioned as necessary in relation to a chamber on the cartridge.
Where components such as sonicators or heaters are fitted to the apparatus in this way, they are generally intended for repeated use and for immersion in a sample, in particular a liquid sample within a chamber.
This in itself, may cause some problems as the use of a non-disposable device in such a way that it comes into direct contact with a sample liquid brings the risk of contamination. Over time, these components may become soiled or tarnished, thus increasing the risk of such contamination.
The applicants have found that this risk can be minimized by placing a sheath, which is disposable, over the processing component before use. In particular, where a processing component such as a heater is used repeatedly during a particular chemical, biochemical procedure or assay, a new disposable sheath is suitably applied on each occasion.
Sheaths of this type are suitably removeably housed on the cartridge in a similar manner to the mechanical elements described above, so that they are readily available and can be accessed and positioned using the arm in a similar fashion. Thus, for example, the sheath may be provided with a lip or flange, able to interact with a fork on the moveable arm of the apparatus and lifted into position around the processing component as necessary.
After use, they may be returned to the cartridge for disposal or disposed of directly.
The sheath is suitably made of a plastics or elastomeric material, and where they are intended for use in conjunction with reusable heaters, they are preferably made of a thermally conducting plastic, for example plastic filled with boron nitride or a commercially available “cool polymer” material, so as to minimize any loses in heater efficiency.
Such sheaths form a further aspect of the invention.
Where heaters are provided in the apparatus, they suitably incorporate temperature sensors, so that the temperature of a reagent or sample in which they are immersed can be determined. When a sheath as described above is used, some calibration of the apparatus will be necessary to ensure that these readings are accurate.
In a particular embodiment, where the apparatus includes both a magnet to facilitate removal of beads or particles from one chamber to another, a heater may be incorporated into the magnet so that the same element may fulfil both functions. For example, heating elements may be incorporated into a core of a bar magnet and this may be used both for the transport of beads or particles, or the heating of vessel or chamber contents.
In that instance, any disposable sheath utilised to cover the magnet when it is deployed in the apparatus is suitably of a heat conducting polymer as described above. Such combined magnet/heaters form a further aspect of the invention.
The apparatus may also comprise devices such as thermal cyclers, optical readers such as fluorimeters, as well as data processing devices arranged to collect, analyse and/or record signals from any chamber within the cartridge or apparatus. The selection and arrangement of suitable devices within the apparatus will depend upon the nature of the chemical and biochemical reaction or assay being conducted, and will be within the ambit of the skilled person.
The inclusion of multiple moveable components and chambers on a cartridge opens up the possibility that the sample preparation and/or analysis may be carried out in a largely self-contained unit comprising the cartridge. Such units, including where all chambers are moveable components, may be readily disposable after use to avoid further contamination risks. Furthermore, by conducting an assay in a single cartridge, it is possible to reduce the risk of errors in sample labelling since the cartridge itself may be labelled at the time of introduction of the sample, for example using a standard bar code labelling system, and the label will remain with the sample throughout the analytical procedure.
All processes are suitably carried out automatically by programming the apparatus to move the relevant components, reagents etc. into contact with each other in an appropriate sequence. For example, as described in WO2005/019836 the sample can be subject to a nucleic acid extraction procedure, followed by a PCR reaction. However, many other procedures in which safe sample delivery is required may be undertaken using the invention by appropriately designing the apparatus and programming it accordingly. The application of such robotic techniques is well known in the art.
When the process includes a thermal cycling step such as a PCR, the apparatus will suitably include a thermal cycling device. The vessel in which the thermal cycling is carried out may be positioned on the cartridge if required. However, alternatively, where the arrangement of the cartridge and the apparatus is such that the preparation of the sample only is carried out on the cartridge, a particularly suitable arrangement is that the prepared sample ends up in a removeable reaction chamber, which is then transferred to a specific thermal cycling area (as illustrated for example in WO2005/019836). However, this may not always be necessary and the incorporation of a chamber which may be thermally cycled on the cartridge would be advantageous in that it would allow further simplification of the apparatus.
Use of electrically conducting polymer as a heater for thermal cycling in particular in PCR reactions, as described and claimed in WO 9824548 (the content of which is incorporated herein by reference), provides a particularly compact and versatile system for use in conjunction with the system of the present application, since the ECP may be readily incorporated into a reaction chamber which is housed, if necessary removeably housed) on the cartridge.
Generally, the ECP is used to coat a reaction vessel which comprises essentially two parts, a relatively wide-mouth upper section for receiving the sample, and a lower sealed capillary tube which then acts as the reaction vessel. At least the lower sealed capillary tube comprises ECP which effectively acts as a highly controllable resistance heater, when electrical contacts are placed across it.
In particular, the reaction vessels used to carry out PCR reactions in particular rapid PCR reactions comprise a capillary tube. Capillary tubes, open at both ends, are used routinely to acquire defined volumes of (eg blood) samples for analysis. They are self-filling by capillary attraction and are generally used as a transfer means.
Capillary tubes are used for rapid PCR applications to provide the optimum profile for heat transfer by providing a minimised distance from the sample to the source of heating or cooling. (Flattened tube formats may also be used for the same reason). Because they need to contain and prevent evaporation from aqueous samples that are being heated, these capillary tubes are sealed at one end, filled and then stoppered.
Filling such capillaries with one end closed presents a problem: surface tension holds the sample to the walls of the tube making a seal that prevents the air in the tube escaping. To overcome this surface tension effect, capillary tubes usually have to be filled by centrifugation to force the liquid into the tube, and such an arrangement is illustrated in for example in WO2005/019836.
For real-time PCR applications where fluorimetry is used to measure optically the formation of product, in addition to the difficulty of filling the tube per se, the presence of residual bubbles of air inside the capillary is problematic because these can move, and expand and contract, and possibly expel portions of the liquid sample, all of which can have optical effects which manifest themselves as noise in the data.
Preparing a capillary tube for PCR normally requires the user to pipette a sample (typically 10-30 microlitres in volume) into a cup formed at the top of the capillary, to place the capillary in a centrifuge, to spin the capillary at around 3,000 rpm for a few seconds (eg 20 seconds), to remove the capillary from the centrifuge, press in a cap and then place the capillary in a thermal cycler. This process can be automated in a single device, also as described in WO2005/019836.
In some circumstances, for example when space is at a premium or when the appropriate configuration of components is not possible, centrifugation may not be available as an option for transferring reaction mixes into capillaries. Another method of filling narrow aspect tubes in a way that avoids the formation of air bubbles is therefore required.
In particular, when using the system of the present invention however, it may be desirable to make the cartridge a different shape to more conveniently accommodate a sample vessel such as a tube. In a particular embodiment for example, the cartridge is generally rectangular in plan view, so that a tube may be accommodated lengthwise through the centre.
The cartridge may contain multiple parallel sample processing units stacked side by side. A non-centrifugal capillary-filling means was needed to fit in with the narrow aspect ratio of the individual modules.
The assay cartridge as described herein, generally uses a pipettor and in particular a pipettor as described in WO 2007/028966 for example to carry out steps such as the rehydration of freeze-dried PCR mix using a buffer containing purified nucleic acid from the sample.
The applicants have found that by modifying the pipettor to make the tip much longer and thinner (for example with an additional about 15-20 mm extension with an outside diameter of less than about 1 mm), it may be used to fill capillary sections of vessels. This is further facilitated by profiling the inside of the capillary section of the reaction chamber so that the upper part tapers smoothly inwards so as to guide the long capillary tip into place, the capillary section of the reaction chamber can be successfully filled without needing to carry out a centrifugation step.
The filling operation can successfully be executed by holding the reaction chamber in a fixed position for example on the cartridge. The pipettor is removeably held in an actuator which can be moved under fine control in a vertical direction. The actuator which holds the pipettor additionally has a co-axial plunger, also under fine control, that can be used to compress the diaphragm on the pipettor so as to draw in or expel liquid samples. The fine control is provided by stepper motors. The actuators can be programmed so that:
1) The pipettor fills with a set volume of PCR reaction mix approximately equal to the empty volume of the capillary 2) The pipettor is then positioned so that the open tip is positioned just above the bottom of the inside of the capillary tube 3) The pipettor is then slowly withdrawn and, as it rises up the capillary, the plunger is controllably depressed onto the diaphragm so as to expel the reagent mix into the capillary so that the capillary is filled without bubbles being formed.
Such methods for filling capilliary tubes have applications outside of the system described above, and thus this forms a further aspect of the invention.
Thus in a further aspect, the invention provides a method for filling a reaction vessel comprising a capillary tube which comprises introducing a filled pipettor with an elongated tip of a diameter less than that of the capillary tube into the tube, and depressing a plunger of the pipettor in a controlled manner so as to expel the contents into the capillary tube and concurrently, withdrawing the elongate tip of the pipettor from the capilliary tube at a speed commensurate with the delivery rate of liquid from the tube.
Modified pipettors, with elongate tips as well as modified reaction vessels with tapering sides above a capillary section of the vessel form yet further aspects of the invention.
The pipettor may take any suitable form, but in particular is a pipettor having an integrated cap member arranged to sealingly close the body, said cap member comprising a resilient diaphragm which is deformable in a downwards direction, as described for example in WO 2007/028966. Such pipettors are particularly suitable for use with mechanical actuators, such as may be found in robotic devices such as those of the preferred embodiments of the system of the present invention.
The invention will now be particularly described by way of example with reference to the accompanying diagrammatic drawings in which:
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows a plan view of a cartridge useful in the system of the invention;
FIG. 2 is a schematic perspective view of a cartridge useful in the system of the invention which is about to receive a sample vessel;
FIG. 3 is a perspective view of the cartridge of FIG. 2 with a sample vessel in place within the holder;
FIG. 4 is a perspective view of the cartridge of FIG. 3 in a “closed” position;
FIG. 5 is an end view of the cartridge of FIG. 4 ;
FIG. 6 is an end view of the cartridge of FIG. 3 ;
FIG. 7 is a schematic diagram showing how a cartridge of the invention may be introduced into a apparatus in which a chemical, biochemical or other type of assay or processing may be conducted;
FIG. 8 illustrates a cartridge of the invention in position in a receiving section of an apparatus;
FIG. 9 is a schematic diagram illustrating a system for filling a capillary tube, which forms a further aspect of the invention; and
FIG. 10 illustrates a piercing element suitable for the cartridge shown in FIGS. 1-6 .
FIG. 11 shows a plan view of the cartridge of FIG. 1 with a sample vessel entering the cartridge.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The cartridge shown in FIG. 1 includes a body section ( 1 ) which is of a rigid plastic material and is of generally oblong section. A clip feature is provided to facilitate location of the cartridge when it is placed in the instrument. A central longitudinal channel ( 2 ) is provided in the upper surface ( 3 ) of the body section ( 1 ). The channel ( 2 ) is open at one end but is does not extend the full length of the body section ( 1 ) so that it terminates in an end ridge ( 4 ) of the body section. The channel ( 2 ) has a generally curved base ( 5 ) and is shaped so that it could accommodate a tube ( 6 ) with a sealing cap ( 7 ). The channel 2 is inclined downwards towards the ridge ( 4 ) so that a liquid sample contained within the tube ( 6 ) will flow towards the cap ( 7 ).
In the illustrated embodiment, the tube accommodates a swab ( 8 ) which is fixed to the cap ( 7 ) by way of a support ( 9 ).
The cartridge also contains a reaction chamber ( 10 ). A piercing needle (not shown) or other piercing element extends between the chamber ( 10 ) towards the cap ( 7 ) with a piercing tip at the end adjacent the cap ( 7 ). The cap ( 7 ) suitably includes a piercable membrane ( 11 ) ( FIG. 2 ) in the upper surface thereof.
When the tube ( 6 ) is in position in the channel ( 2 ), the cap ( 7 ) is sufficiently far removed from the piercing needle or element to ensure that it is not breached. However, the cartridge ( 1 ) is designed to be positioned within an apparatus (not shown), which is provided with an actuator able to apply pressure to the base of the tube ( 6 ) in the direction of the arrow. This forces the membrane ( 11 ) of the cap ( 7 ) against the piercing needle or element, which passes through the membrane ( 11 ) and thus breaches the seal.
Any liquid within the tube ( 6 ) is able to flow out through a channel in the needle or piercing element into the reaction chamber 10 , where it may be subject to further processing. However, no operator contact with the contents of the tube ( 6 ) has taken place at this point and so the risk of contamination is minimised.
FIG. 10 illustrates a piercing element suitable for use in the cartridge. The piercing element ( 40 ) is made from plastics material and has a cylindrical body ( 42 ) with one end cut obliquely to form a sharp point ( 46 ). A slit ( 44 ) runs along the top of the piercing element, which prevents an air lock being formed when the piercing element ( 40 ) pierces the cap of the tube, preventing the sample from flowing through the piercing element into the reaction chamber. This piercing element forms a neat hole of round cross section. However, piercing element s of other cross section could be used.
The cartridge ( 1 ) also includes in side sections a number of components or elements which may be utilised in an automated analytical process. For instance, it contains a number of foil sealed reservoirs ( 12 ) which may contain liquid reagents such as buffers, washes etc. which may be required for the desired processing of a sample. Others ( 13 ) may contain reagents such as solid reagents such as PCR beads useful in the subsequent processing of the sample.
In addition in this instance, the cartridge includes a series of movable components including two pipettors 14 , a stopper 15 and a sheath 16 which may fit for example over a magnet used to move magnetic reagent beads from one chamber to another on the cartridge as required. These moveable components are accommodated within appropriately shaped apertures in the upper surface ( 3 ) of the body section ( 1 ). They are arranged so that an upper region projects above the upper surface ( 3 ) so that they are accessible for a grabbing arm of an apparatus. They may be provided with suitable annular flanges to facilitate this, or to assist in the lifting operation, for example as described in WO2005/019636.
In this case also, there is a provided in the cartridge ( 1 ), a reaction vessel ( 17 ) which is coated with an electrically conducting polymer, and so which, when connected to a suitable electrical supply, can subject the contents to a thermal cycling procedure such as that required for PCR.
The arrangement of this vessel will discussed in more detail hereinafter in relation to other illustrated embodiments.
The cartridge illustrated in FIG. 2 contains many common elements although these are slightly differently arranged to suit the particular apparatus and chemical, biochemical or analytic procedure or assay being carried out. However, in this case, a holder ( 18 ) for the tube ( 6 ) is provided. The holder ( 18 ) is also tubular in shape and is capable of holding the tube ( 6 ) such that the cap ( 7 ) abuts against the end ( FIG. 3 ).
The holder ( 18 ) may be retained against the cartridge body ( 1 ) in an upright sample vessel receiving position by means of a clasp ( 20 ) ( FIGS. 5 and 6 ) disposed at the free end of the channel ( 2 ).
Once a tube ( 6 ) has been loaded into the holder ( 18 ), it is removed from the clasp ( 20 ), and inserted into the channel ( 2 ). A flange ( 19 ) provided on the side of the holder ( 18 ) is arranged to engage in a snap fit locking arrangement with a corresponding groove in the ridge ( 4 ) of the body section ( 1 ), but only if the tube ( 6 ) is snugly fitted into the holder ( 18 ) ( FIG. 4 ).
At this point, the tube ( 6 ) and the cap ( 7 ) are substantially completely encased within the cartridge and holder and so are not accessible for fracture etc. A space ( 22 ) for a label for a bar-code reader to identify the cartridge and a window ( 23 ) to allow a bar-code on the sample tube to be read may be provided on the flange ( 19 ) and holder ( 18 ) respectively.
Sample labels may be applied at this point to the cartridge for example bar code labels which may be applied to an end region ( 21 ) of the body section ( 1 ), so as to facilitate tracking of the sample through the analytical procedure.
The base of the holder ( 18 ) includes a small aperture ( 24 ) ( FIG. 5 ). The aperture ( 24 ) is shaped to allow an actuator of the apparatus into which the cartridge is introduced to pass through and so urge the tube ( 6 ) towards the piercing needle or piercing element provided at the region of the ridge ( 4 )
Once the actuator has passed through the aperture ( 24 ), the cartridge is effectively “locked” and cannot then be opened. The actuator is then withdrawn whilst the sample tube remains in position at least until the end of the analytical procedure.
The cartridge ( 1 ) is shaped so that it may be received into a receiving section of a suitable apparatus. This is illustrated schematically in FIG. 7 . In that case, the cartridge receiving section of the apparatus ( 36 ) comprises a support ( 37 ) provided with a recess ( 38 ), into which the cartridge ( 1 ) snugly fits. The support ( 37 ) is retractable into the body of the apparatus ( 36 ), for processing. The support ( 36 ) is itself moveable (see arrows) so as to align any particular part of the cartridge ( 1 ) with an interacting element ( 39 ), which may be moveable in a vertical direction.
A similar arrangement, is illustrated in FIG. 8 . In this case, the cartridge ( 1 ) is provided with a lip ( 40 ) which engages the upper surface of the support ( 37 ) when the cartridge is in position within the recess ( 38 ). The holder ( 18 ) is arranged so that when the support ( 37 ) is retracted into the body of the apparatus, the actuator for opening the tube ( 6 ) and can enter through the aperture ( 11 ) to release sample into the sample vessel ( 10 ) prior to the processing procedure. If required, locking or other engagement means may be provided to fix the cartridge ( 1 ) in position on the support ( 37 ).
Thus in use, a sample is collected for example for chemical, biochemical analysis, investigation or assay. If the sample is a liquid sample, it is suitably placed directly in a tube ( 6 ) which is sealed with a cap ( 7 ). Preferably the volume of the sample is known or is measured, in particular if the nature of the investigation being carried out is qualitative in nature. The sample tube may be inscribed with maximum and minimum fill lines to facilitate the dispensing of the liquid sample and to provide a means of checking that the sample volume is within the required limits. If the sample has been collected on a swab, then the swab ( 8 ) itself is placed in the tube together with a suitable and preferably known volume of eluent and the tube ( 6 ) is then sealed with a cap ( 7 ). The tube is then suitably shaken to ensure that any sample is transferred from the swab ( 8 ) to the eluent, although this may not be necessary if the volume of the liquid is sufficient to ensure that the swab remains immersed in the liquid.
Then either directly, or when it reaches a laboratory, the tube ( 6 ) is placed in a holder ( 18 ) of a cartridge. The holder is then inserted into the channel ( 2 ) of the body section ( 1 ) of a cartridge and the cartridge itself is labelled, before being placed into an appropriate cartridge receiving section of an apparatus (designed to effect the necessary procedures so as to effect the chemical, biochemical or analytical procedures or assays on the sample).
At this point, an actuator on the apparatus is caused to pass through the aperture ( 24 ) in the base of the holder ( 18 ) so as to urge the tube ( 7 ) towards the hollow piercing needle or other piercing element at the ridge end of the cartridge. Sufficient pressure is applied to the tube ( 6 ) by the actuator ( 24 ) to ensure that the rubber seal ( 11 ) in the cap ( 7 ) is breached by the needle or piercing element.
Because the tube ( 6 ) is inclined downwards towards the ridge ( 4 ), the liquid contained therein will run through the hollow piercing needle or piercing element directly into the reaction chamber ( 10 ) on the cartridge.
The apparatus is then able to effect processing, for example using robotic procedures known in the art. A vertically moveable arm is suitably used to effect the processing, whilst the cartridge is moveable, for example by Cartesian motion, so that the appropriate chamber or component on the cartridge is aligned with the arm at any one time.
The possibility for assay design using this procedure is limitless, as all that it is necessary to do in any particular case is to ensure that reagent containers on the cartridge and that suitable other components such as the moveable components described hereinbefore, are provided either on the cartridge or integrated appropriately into the apparatus.
A particular example of such a procedure is illustrated in WO2005/019836.
To summarise that procedure however, a sample within the chamber 10 which is known or suspected of containing cells of interest is subject to cell lysis. This may be achieved for example by preloading the chamber 10 with a chemical lysis agent such as guanidine hydrochloride, by adding such a reagent taken from a reagent container for example using a pipettor 14 , by introduction of a sonicator which is suitably intergral with the apparatus or a combination of these. Where reagents are obtained from a sealed container 12 on the cartridge, they may be accessed following piercing of the foil lids with a cutter, which itself may be a moveable component on the cartridge or an integral part of the apparatus.
Magnetic beads which are suitably coated with a binding agent such an antibody specific for a particular target analyte or nucleic acid generically, such as “Magnesil®” silica beads are then introduced, for example using a magnet which is inserted into a sheath 16 and brought into contact with beads when it attraction is required (for example to pick the beads out of a container) and removed from the sheath when the beads are required to be deposited, for instance once the sheath has been positioned inside the reaction chamber 10 .
After allowing the analyte such as any nucleic acid to become adhered to the beads, they may be removed from the reaction chamber ( 10 ) and placed into a different reaction chamber, which may have been foil sealed until the seal was broken by a suitable cutter before addition of the analyte. The beads may be moved through one or more wash chambers, optionally present on the cartridge, at this time if required.
Analyte may then be eluted from the beads for example by adding eluent, which is preferably hot, to a chamber containing the beads. Heating of the eluent may take place by introducing a heater provided on the apparatus, which is preferably encased within a protective disposable sheath 16 as described above. However, in the event that it is not, it may be subject to washing steps using wash liquids which may be contained in reagent chambers which are optionally on the cartridge.
Reagents suitable for carrying out a PCR reaction may also be prepared in a reaction chamber, for example by addition of a suitable buffer, in particular one containing purified nucleic acid extracted from the sample, to lyophilised beads of PCR reagents. Again, such procedures may be effected automatically within the apparatus by moving elements such as the cutter, pipettors etc so as to ensure that the appropriate reagent transfers occur.
Once a PCR reaction mixture has been prepared on the cartridge, it is suitably transferred into the reaction chamber 17 , which is thermally cyclable as a result of an ECP (electrically conductive polymer) coating. Filling is achieved by means of a modified pipettor and the procedure is illustrated in FIG. 9 .
As illustrated, the pipettor comprises a plastics body ( 25 ) provided with a series of annular flanges ( 26 ) which facilitate the collection of the pipettor by an arm of the apparatus. A cap member ( 27 ) has a resilient upper diaphragm ( 28 ) with a projection ( 29 ) intended to interact with an actuator provided on the apparatus, so as to allow controlled operation of the pipettor.
The lower section ( 30 ) of the pipettor is substantially elongate and of a sufficiently small diameter to enter a capillary tube ( 31 ). The capillary tube ( 31 ) is sealed at the lower end ( 32 ) and so forms a closed reaction vessel. The lower surface ( 32 ) is suitably transparent so that the progress of any reaction carried out in the vessel can be viewed. This means that, for example where the PCR is carried out in the presence of a fluorescent signalling system, it can be monitored throughout (real-time PCR). The upper portion ( 33 ) of the reaction vessel is of a wider cross section, but the walls in the region of the juncture of the upper portion ( 33 ) and capillary tube ( 31 ) are tapered so as to provide a guide for the lower section of the pipettor ( 30 ) as it enters the capillary tube ( 31 ).
An electrically conducting polymer layer ( 34 ) surrounds the capillary tube, and is connectable to an electrical supply by way of upper and lower electrical contacts ( 35 , 36 ).
In use, the pipettor 14 is raised out of its housing with the cartridge by the interaction of the arm with the flanges 26 , and lowered into a reaction chamber containing the prepared PCR reaction mixture. The pipettor actuator, driven by a stepper motor is deployed to depress the diaphragm ( 28 ) so as to draw the reaction mixture up into the pipettor body ( 25 ).
The pipettor is then raised out of the chamber by the moveable arm of the apparatus, the cartridge is moved so that the pipettor is located above the reaction vessel ( 17 ), and then lowered, until the lower section ( 30 ) of the pipettor ( 14 ) is substantially at the base ( 32 ) of the capillary tube.
The actuator for the diaphragm ( 28 ) is once again activated to expel the contents into the reaction vessel ( 17 ). At the same time, the arm is deployed to raise the pipettor ( 14 ) out of the reaction vessel ( 17 ). The movement of the arm and the actuator are co-ordinated so that the pipettor ( 14 ) leaves the capillary tube ( 31 ) at a suitable rate to provide bubble free filling.
The accuracy and controllability of the actuator and the arm as a result of the use of suitable controlling stepper motors, means that such an operation is possible.
Once the reaction vessel ( 17 ) has been filled in this way, a suitable cap or stopper may be applied to the upper section ( 33 ) to close the vessel. The electrical contacts 35 , 36 may be connected so as to allow a thermal cycling process, for example a PCR reaction, to be conducted, within the reaction vessel ( 17 ) without further movement.
Suitably, the PCR includes one of the conventional signalling systems such as the Taqman™ or ResonSense™ methodologies and this is monitored through a transparent base ( 32 ) of the tube.
Once complete, the cartridge may be removed from the apparatus and discarded.
The systems and elements described herein therefore provide an effective and efficient way of conducting a variety of procedures, in particular chemical, biochemical or analytical assays, whilst minimising risks of contamination and false positive results which this may introduce. | A sample delivery system comprising (i) a cartridge comprising a body section adapted to hold a sealed sample vessel so as to fix the position of a seal of the sample vessel in relation to the cartridge; and (ii) apparatus adapted to receive said cartridge, said apparatus being provided with an opening system for opening said sealed sample vessel contained within the cartridge. | 1 |
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of my copending application Ser. No. 576,031, filed May 9, 1975, now U.S. Pat. No. 4,002,116, issued Jan. 11, 1977.
BACKGROUND OF INVENTION
One type of conventional floor truss which is used for supporting building floor surfaces, roof decks, and the like, is formed of a pair of parallel, wooden chords, such as 2×4 wood strips, arranged one above the other, and interconnected by diagonally arranged webs or struts made of sheet metal. The webs are fastened, at their opposite ends, to the respective chords by means of nailing or by overlapping them with so-called "connector plates" which are flat plates having struck-out teeth which extend through holes in the web ends, for embedding within the wooden chords. Such types of trusses are normally manufactured in a factory building and transported to a construction site for installation as part of a building.
In the manufacture of such trusses, it is important to utilize as inexpensive a construction as possible, consistent with providing desired strengths. It is also important to utilize the truss in a manner which will reduce the shear stress in the chord.
Thus, the invention herein relates to an improved web device which requires minimum handling and which is of a construction that provides maximum strength to the truss, and also an improved structure including such a web device.
SUMMARY OF INVENTION
The invention herein relates first to an improved metal web which is of approximately V-shape or chevron-shaped, formed of flat sheet metal, to provide a pair of diverging legs forming webs, and an integral apex and web end connector plate portions each having struck-out teeth for embedding within the wooden chords. The combination web-connector construction is for applying against the sides only of a pair of vertically aligned chords and is so configured as to easily absorb, transmit and neutralize the various compressive and tensile forces applied to the completed truss.
The chevron construction permits the manufacture of the webs out of a single flat sheet of metal, such as steel, by stamping or slitting successive nested webs, thereby minimizing scrap losses in the manufacturing process. Thus, the completed web construction is relatively inexpensive, easy to handle and easily positionable in place upon aligned chords for assembly thereto.
The invention herein also is concerned with the relationship of the chords and the web. Specifically, the web plate is offset inwardly from the end of the chord. The web plate is positioned to overlap a beam, stud or columnar support to reduce shear stress in the chords.
These and other objects and other advantages of this invention will become apparent upon reading the following description, of which the attached drawings form a part.
DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of a section of the truss which forms a floor or roof deck joist.
FIG. 2 is an enlarged, fragmentary, cross-sectional view of one chord and the attached webs.
FIG. 3 is an enlarged elevational view of a single web-connector and
FIG. 4 is a side elevational view of the web-connector.
FIG. 5 is a cross-sectional view taken in the direction of arrows 5--5 of one web, and
FIG. 6 is a cross-sectional view taken in the direction of arrows 6--6 of FIG. 3 of the apex connector portion of the web-connector.
FIG. 7 illustrates the nesting relationship of the webs as they are formed into blanks from a sheet of metal.
FIG. 8 is a partial front elevation of a joist with the upper chord and web plate bearing on a columnar support;
FIG. 9 is a partial cross-section as seen in the plane of arrows 9--9 of FIG. 8.
FIG. 10 is a partial front elevation of a joist with the lower chord and web plate bearing on a columnar support; and
FIG. 11 is a partial cross-section as seen in the plane of arrows 11--11 of FIG. 10.
DETAILED DESCRIPTION
FIG. 1 illustrates a section of a truss type joist formed of a pair of vertically spaced apart wood chord members 11 which may be of conventional 2×4 lumber. The chords are interconnected by diagonally arranged struts or webs formed of sheet metal. Such metal webs 12 are made in a chevron or V-shape to provide web legs 13, an apex connector plate portion 14 and enlarged leg connector portions 15. The connector portions are provided with struckout spikes or teeth 16 for embedding into the chord members.
The edges of the web legs are bent to form a continuous inner flange 17 which extends substantially the full length of each leg and continues around the arc forming the apex between the legs, and an outer flange 18.
A channel or groove 19 is formed along the length of each leg by bending or impressing for rigidifying the legs in conjunction with the flanges.
As shown in FIG. 7, the web-connectors may be formed by starting with an elongated sheet of metal, such as suitable sheet steel of adequate strength and then blanks 12a may be stamped or slit from the sheet. These blanks are in effect, nested, one within the other. To form the complete web-connectors, the blanks are first, partially lanced; second, formed or flanged; third, teeth punched; and last, finally cut off the sheet, while the sheet passes through a progressive die. Thus, as can be seen, in the manufacturing process for forming the web-connectors, there is a minimum of waste material, which obviously reduces the overall cost of manufacture.
The size, i.e., the height of the web-connectors may be varied in the manufacturing process by using stamping dies which have fixed inserts for the connector portions and teeth and removable leg-forming portions which can be interchanged with other leg-forming portions to make the legs longer or shorter, as desired. Thus, the die expense, due to the configuration of the web-connector, is substantially reduced.
As best illustrated in FIGS. 2, 4 and 5 the central rib 19 is raised above the plane of the legs in a first direction. The inner and outer flanges 17, 18 and the teeth 16 all extend below the plane of the legs in the opposite direction.
As seen in FIGS. 3 and 7 the inner edge or inner flange 17 of each leg extends in a substantially straight line to form the interior edge of the enlarged end portion. This interior edge of the enlarged end is commonly referred to as the heel. Each enlarged end portion extends outwardly from its corresponding heel to its outer edge in a direction transverse of the central axis of the respective leg. This minimizes the waste in the aforementioned manufacture of successive nested webs as illustrated in FIG. 7.
The locator holes 65, as set forth in the aforementioned copending application, receive locator pins during assembly of the joists so that the webs are properly aligned relative to the chords.
As can be seen in FIGS. 1 and 2, the web-connectors are applied in pairs, one on each vertical face of the aligned chords, and their teeth are embedded only into the side faces of the chords. This permits forming the truss by laying one web-connector down upon a horizontal surface, with its teeth upwardly, laying the chords above it and then placing the second or opposing web-connector upon the exposed upper surfaces of the chords, teeth down, so that a single compression or clamping operation at each overlapped connector portion can cause the teeth thereof to move into the wood from opposite sides. Thus, the assembly of the web-connectors to the wood chords is simplified to a considerable extent and permits the use of the apparatus therein.
With the specific design of the web-connector, edge flanges, apex arrangement, etc., the loads applied upon the joist which is formed by this truss, places one leg of each web-connector in compression and the other leg in tension, with the resulting force component, longitudinal of each chord. The net result is balancing or approximate cancellation of vertical force components, and absorbtion of longitudinal force components, as well as resistance against torque or twisting forces. Hence, a good, strong joist is provided using minimal materials.
Referring now to FIGS. 8-11 the utilization of the truss of the present invention will be explained. FIGS. 8 and 9 illustrate a first embodiment of a truss having upper and lower chords 11,11 1 interconnected by a web-connector 12. The end plate 15 is offset inwardly from the end 25 of the upper chord 11 approximately two and a half inches. The upper chord bears on a stud or beam 26, preferably of wood, which in turn bears on a columnar support 27. Support 27 is illustrated as a brick wall but may be any type of support wall, beam, or stud, etc. The end 28 of the end connector plate 15 overlaps the stud 26 by approximately one inch.
By providing this overlap of the end plate 15, the load bears directly from the web-connector plate into the stud 26 and then to the support column. This substantially reduces the shearing forces and shear stress on the upper chord 11.
As illustrated in FIGS. 10 and 11, the inventive concept of overlapping the end plate to bear on a support column may be employed on the bottom chord. FIGS. 10 and 11 illustrate such a construction with the end 30 of the connector end plate 15 overlapping a beam or stud 26 so that the load bears on the support column 27 and shear is reduced in the lower chord 11 1 . A cross strut 31 may be used to interconnect chords 11 and 11 1 . | A V-shaped, substantially flat, sheet metal, combined web-connector plate having diverging web-forming legs and integral apex and leg end connector portions provided with struck-out teeth for embedding within spaced apart wooden chord members to form a wood chord-metal web type truss. The connector plate is offset inwardly from the end of the chord and the connector plate is positioned to slightly overlap a beam or columnar support to reduce shear stress in the chord. | 4 |
[0001] This invention was made with U.S. Government support under Contract Number DE-FC26-05NT42644 awarded by the U.S. Department of Energy. The U.S. Government has certain rights to this invention.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a disc seal assembly for use in a turbine engine, and more particularly, to a disc seal assembly including a plurality of sealing flange members that define a labyrinth flow path to limit leakage between a disc cavity and a hot gas passage in the turbine engine.
BACKGROUND OF THE INVENTION
[0003] In multistage rotary machines used for energy conversion for example, a fluid is used to produce rotational motion. In a gas turbine engine, for example, a gas is compressed in a compressor and mixed with a fuel source in a combustor. The combination of gas and fuel is then ignited for generating combustion gases (hot gas) that are directed to turbine stage(s) to produce rotational motion. Both the turbine stage(s) and the compressor have stationary or non-rotary components, such as vanes, for example, that cooperate with rotatable components, such as rotor blades, for example, for compressing and expanding the operational gases. Many components within the machines must be cooled by cooling air to prevent the components from overheating.
[0004] Cooling air and hot gas leakage between a hot gas path and a disc cavity in the machines reduces performance and efficiency. Cooling air leakage from the disc cavities into the hot gas path in airfoil channels can disrupt the flow of the hot gas and increase heat losses. Further, as more cooling air is leaked into the hot gas path, the higher the primary zone temperature in the combustor must be to achieve the required engine firing temperature. Additionally, hot gas leakage into the disc cavities yields higher disc and blade root temperatures and may result in reduced performance and reduced service life and/or failure of the components in the disc cavities.
[0005] In view of higher pressure ratios and higher engine firing temperatures implemented in modern machines, it is increasingly important to limit leakage between the hot gas path and the disc cavity in the machines to maximize performance and efficiency thereof.
[0006] In view of the foregoing considerations it would be desirable to provide a seal arrangement for use in a rotary machine, whereby the placement and configuration of sealing flanges in the arrangement limits leakage between the hot gas path and the disc cavity to thereby improve performance and efficiency of the rotary machine.
SUMMARY OF THE INVENTION
[0007] In accordance with a first aspect of the present invention, a seal assembly is provided for limiting gas leakage between a hot gas path and a disc cavity in a turbine engine comprising a plurality of stages, each stage comprising a plurality of stationary components connected by an annular inner shroud and a rotating disc supporting a plurality of blades. The seal assembly comprises a wing member extending axially from a side of the disc toward a radial surface of the annular inner shroud. The wing member includes an inner side and an outer side and a first wing flange extending radially outwardly from the outer side of the wing member toward an axial surface of the inner shroud. A first shroud flange extends radially inwardly from the axial surface of the inner shroud toward the outer side of the wing member to form, with the first wing flange, a labyrinth path between the hot gas path and the disc cavity.
[0008] In accordance with a second aspect of the present invention, a seal assembly is provided for limiting gas leakage between a hot gas path and a disc cavity in a turbine engine comprising a plurality of stages, each stage comprising a plurality of stationary components connected by an annular inner shroud and a rotating disc supporting a plurality of blades. The seal assembly comprises a wing member extending axially from a side of the disc toward a radial surface of the annular inner shroud. The wing member includes an inner side and an outer side, and a first wing flange extending radially outwardly from the outer side of the wing member toward an axial surface of the inner shroud. A second wing flange extends radially inwardly from the inner side of the wing member opposite from the first wing flange. A first shroud flange extends radially inwardly from the axial surface of the inner shroud toward the outer side of the wing member to form, with the first wing flange, a labyrinth path between the hot gas path and the disc cavity.
[0009] In accordance with a third aspect of the present invention a seal assembly is provided for limiting gas leakage between a hot gas path and a disc cavity in a turbine engine comprising a plurality of stages, each stage comprising a plurality of stationary components connected by an annular inner shroud and a rotating disc supporting a plurality of blades. The seal assembly comprises a wing member extending axially from a side of the disc toward a radial surface of the annular inner shroud. The wing member includes an inner side and an outer side, and a first wing flange extending radially outwardly from the outer side of the wing member toward an axial surface of the inner shroud. The first wing flange is curved extending in the radial direction and having a concave side facing the disc. A second wing flange extends radially inwardly from the inner side of the wing member opposite from the first wing flange. The second wing flange is curved extending in the radial direction and having a concave side facing the disc. A first shroud flange extends radially inwardly from the axial surface of the inner shroud toward the outer side of the wing member to form, with the first wing flange, a labyrinth path between the hot gas path and the disc cavity, wherein the first shroud flange includes a lip member extending axially from a distal end of the first shroud flange toward the first wing flange. A second shroud flange extends axially from the radial surface of the inner shroud toward the disc at a radial location generally between the first wing flange and the second wing flange.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying Drawing Figures, in which like reference numerals identify like elements, and wherein:
[0011] FIG. 1 is a diagrammatic sectional view of a portion of a gas turbine engine including a disc seal assembly in accordance with the invention;
[0012] FIG. 2 is an enlarged sectional view of the disc seal assembly illustrated in FIG. 1 ; and
[0013] FIG. 3 is an enlarged sectional view of a disc seal assembly in accordance with another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0014] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, and not by way of limitation, specific preferred embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention.
[0015] Referring to FIG. 1 , a portion of a turbine engine 10 is illustrated diagrammatically including adjoining stages 12 , 14 , each stage comprising an array of stationary components, illustrated herein as vanes 16 , supported on inner shrouds 17 , and an array of rotating blades 18 supported on platforms 40 mounted to rotor discs 20 . The vanes 16 and the blades 18 are positioned circumferentially within the engine 10 with alternating vanes 16 and blades 18 located in the axial direction of the engine 10 . The rotor discs 20 are secured to adjacent discs 20 with spindle bolts 22 . The vanes 16 and the blades 18 extend into an annular gas passage 24 , and hot gases directed through the gas passage 24 flow past the vanes 16 and the blades 18 to remaining rotating elements.
[0016] First disc cavities 26 and second disc cavities 28 are illustrated located radially inwardly from the gas passage 24 . Purge air is provided from cooling gas passing through internal passages (not shown) in the vanes 16 and inner shrouds 17 to the disc cavities 26 , 28 to cool the blades 18 . The purge air also provides a pressure balance against the pressure of the hot gases flowing in the gas passage 24 to counteract a flow of the hot gases into the disc cavities 26 , 28 . In addition, interstage seals comprising labyrinth seals 30 may be supported at the radially inner side of the inner shrouds 17 and are engaged with surfaces defined on paired annular disc arms 32 , 34 extending axially from opposed portions of adjoining discs 20 . An annular cooling cavity 36 is formed between the opposed portions of adjoining discs 20 on an inner side of the paired annular disc arms 32 , 34 . The annular cooling cavity 36 receives cooling air passing through disc passages (not shown) to cool the discs 20 .
[0017] Structure on the discs 20 and the inner shrouds 17 cooperate to form annular disc sealing assemblies 38 between the gas passage 24 and the disc cavities 26 , 28 , as more clearly shown in FIG. 2 . For exemplary purposes, only one disc sealing assembly 38 formed between the gas passage 24 and the first disc cavity 26 will be described. However, it is understood that the other disc sealing assemblies 38 formed between the gas passage 24 and other disc cavities 26 , 28 within the engine 10 are generally identical to or are substantially mirror images of the disc sealing assembly 38 described.
[0018] FIG. 2 shows an enlarged view illustrating the disc sealing assembly 38 . A wing member 44 extends axially from a first side 46 of the disc 20 toward a radial surface 48 of the inner shroud 17 . In the embodiment shown, the wing member 44 is formed from a high temperature alloy, such as for example an INCONEL alloy (INCONEL is a registered trademark of Special Metals Corporation), although any suitable material may be used to form the wing member 44 as desired.
[0019] Although only a single wing member 44 is shown, it should be understood that a plurality of wing members 44 may be employed to form the disc sealing assembly 38 as desired. If multiple wing members 44 are used to form the disc sealing assembly 38 , the wing members 44 are preferably located adjacent to each other extending circumferentially about the disc 20 , and the wing members 44 may include cooperating ramped or angled overlapping edges (not shown) to reduce spacing between adjacent wing members 44 and provide a sealing interface for restricting passage of gases between adjacent wing members 44 .
[0020] The wing member 44 includes an outer side 50 facing radially outwardly from the wing member 44 and an inner side 52 facing radially inwardly from the wing member 44 . The outer side 50 and inner side 52 may be generally arcuate shaped in the circumferential direction to substantially correspond to the arcuate shape of the disc 20 when viewed axially.
[0021] A first wing flange 54 extends radially outwardly from the outer side 50 of the wing member 44 toward an axial surface 56 of the inner shroud 17 , the axial surface 56 of the inner shroud 17 is located adjacent to and extends in a transverse direction from the radial surface 48 of the inner shroud 17 . In the embodiment shown, the first wing flange 54 is formed from a high temperature alloy, such as an INCONEL alloy, for example, although any suitable material may be used to form the first wing flange 54 as desired. The first wing flange 54 may be arcuate shaped in the circumferential direction to substantially correspond to the arcuate shape of the disc 20 when viewed axially. In addition, the first wing flange 54 may be curved in the radial direction and include a concave side 58 facing the disc 20 . A distal end 60 of the first wing flange 54 is located adjacent to the axial surface 56 of the inner shroud 17 .
[0022] A second wing flange 62 extends radially inwardly from the inner side 52 of the wing member 44 . In the embodiment shown, the second wing flange 62 is formed from a high temperature alloy, such as an INCONEL alloy, for example, although any suitable material may be used to form the second wing flange 62 as desired. The second wing flange 62 may be arcuate shaped in the circumferential direction to substantially correspond to the arcuate shape of the disc 20 when viewed axially. In addition, the second wing flange 62 may be curved in the radial direction and include a concave side 64 facing the disc 20 .
[0023] The inner shroud 17 includes a first shroud flange 66 that extends radially inwardly from the axial surface 56 of the inner shroud 17 toward a location adjacent the outer side 50 of the wing member 44 . The first shroud flange 66 may be arcuate shaped in the circumferential direction to substantially correspond to the arcuate shape of the inner shroud 17 when viewed axially. In the embodiment shown, the first shroud flange 66 is located at an axial location between the first wing flange 54 and the disc 20 . The first shroud flange 66 includes a lip member 68 that extends axially from a distal end 70 of the first shroud flange 66 toward the first wing flange 54 . A first fluid pocket P 1 is formed between the first shroud flange 66 and the disc 20 . A second fluid pocket P 2 is formed between the first wing flange 54 and the first shroud flange 66 .
[0024] The inner shroud 17 also includes a second shroud flange 74 that extends axially from the radial surface 48 of the inner shroud 17 toward the wing member 44 . The second shroud flange 74 may be arcuate shaped in the circumferential direction to substantially correspond to the arcuate shape of the inner shroud 17 when viewed axially. In the embodiment shown, the second shroud flange 74 is located at a radial location generally between the first wing flange 54 and the second wing flange 62 and includes a distal end 75 located adjacent to a wing flange midpoint 69 between the first and second wing flanges 54 , 62 . A third fluid pocket P 3 is formed by the first wing flange 54 , the inner shroud 17 , and the second shroud flange 74 . The first wing flange 54 , the first shroud flange 66 , and the lip member 68 cooperate to form a labyrinth path in the second fluid pocket P 2 , extending between the first fluid pocket P 1 and the third fluid pocket P 3 and indicated by the dashed line 72 in FIG. 2 .
[0025] It should be noted that the surfaces of the wing member 44 , including the surfaces of the first and second wing flanges 54 , 62 , may be hardened or coated with a hard material in order to prevent or reduce abrasion and wear of these surfaces in the event that rubbing contact occurs with adjacent stationary surfaces.
[0026] During operation of the engine 10 , the cooling air in the disc cavity 26 is pumped radially outwardly by the rotation of the disc 20 . The curved configuration of the second wing flange 62 acts as an aerodynamic break and deflects the outward flowing disc boundary layer flow of air away from the disc 20 and forcing it to turn 180 degrees to pass around the edge of the second wing flange 62 . That is, the air of the boundary layer flow must flow in a direction radially inwardly toward the rotational axis of the disc 20 and then turn 180 degrees around the edge of the second wing flange 62 in order to flow radially outwardly past the wing member 44 along an outer convex side 65 of the second wing flange 62 . A limited gap or passage area is defined between the distal end 75 of the second shroud flange 74 and the wing flange midpoint 69 which operates to further restrict radial outward flow of cooling air from the disc cavity 26 into the third fluid pocket P 3 .
[0027] Once cooling air or gas passes into the third fluid pocket P 3 , it must follow a tortuous path defined by the labyrinth path 72 in order to escape into the gas passage 24 . Specifically, gas located within the third fluid pocket P 3 must pass around the distal end 60 of the first wing flange 54 and turn 180 degrees to enter the second fluid pocket P 2 , moving in a direction counter to the centrifugal outward pumping forces associated with the fluid boundary layer of the first wing flange 54 . Gas in the second fluid pocket P 2 must again turn 180 degrees to pass out of the second fluid pocket P 2 and into the first fluid pocket P 1 and the gas passage 24 . It should be noted that the lip 68 forces gas in the second fluid pocket P 2 to move toward an outwardly moving boundary layer associated with the concave side 58 of the first wing flange 54 to further counteract movement of gas from the second fluid pocket P 2 toward the gas passage 24 . It should also be understood that the restricted passages defined adjacent the distal end 60 of the first wing flange 54 and adjacent the distal end 70 of the first shroud flange 66 further act to restrict passage of gas through the labyrinth path 72 to the gas passage 24 .
[0028] In addition to restricting a flow of cooling air into the gas passage 24 , the sealing assembly 38 also provides a tortuous labyrinth path 72 that hot gases from the gas passage 24 must overcome in order to enter the disc cavity 26 . In addition, a pressure rise associated with the restricted seal clearances defined at the distal ends 60 , 70 , 75 of the first wing flange 54 and the first and second shroud flanges 66 , 74 , respectively, further counteracts movement of the hot gases into the disc cavity 26 .
[0029] FIG. 3 shows an enlarged view illustrating a disc sealing assembly 138 in accordance with another embodiment of the invention, wherein corresponding structure to that described above with reference to FIGS. 1 and 2 is identified by the same reference increased by 100. With the exception of a cover plate 147 , a first flexible seal 159 , a second flexible seal 163 and the particular structure of a portion of the a blade platform 140 associated with each of the blades 118 , the disc sealing assembly 138 is substantially identical to the disc sealing assembly 38 discussed above with reference to FIGS. 1 and 2 . Accordingly, only these components and their associated functions will now be described.
[0030] The blade platform 140 supports a blade 118 thereon and includes a circumferentially extending annular groove 141 located adjacent an outer lip 143 thereof. The cover plate 147 may be provided as a cover for the axial end of the blade root of one or more blades 118 and is shown as including a radial outer edge 149 . The radial outer edge 149 is received in the annular groove 141 of the blade platform 140 and the cover plate 147 may be further mechanically secured in place, such as by clamping, peening, screwing, or other mechanical securing means, for example. It should be understood that a plurality of cover plates 147 may be provided around the circumference of the disc 120 , and that each cover plate 147 may include one or more wing members 144 to form the disc sealing assemblies 138 . The wing member 144 extends from the cover plate 147 toward a radial surface 148 of an inner shroud 117 .
[0031] The first flexible seal 159 is disposed on a concave side 158 of a first wing flange 154 near a distal end 160 thereof and may be attached to the first wing flange 154 , such as by welding. In the embodiment shown, the first flexible seal 159 is formed from a high temperature alloy, such as an INCONEL alloy, for example, although any suitable material may be used to form the first flexible seal 159 as desired. A thickness of the first flexible seal 159 in the embodiment shown is approximately 0.040 inches (approximately ⅓ of a thickness of the first wing flange 154 ), although the first flexible seal 159 may have other thicknesses as desired. The first flexible seal 159 may be arcuate shaped to substantially correspond to the arcuate shape of the disc 120 when viewed axially. In the embodiment shown, the first flexible seal 159 is curved in the axial direction and has a concave side 161 facing an axial surface 156 of the inner shroud 117 . Also in the embodiment shown, the first flexible seal 159 extends around a distal end 170 of a first shroud flange 166 , including a lip member 168 .
[0032] The second flexible seal 163 is disposed on a convex side 165 of a second wing flange 162 , is curved in the radial direction and extends axially toward a radial surface 148 of the inner shroud 117 . In the embodiment shown, the second flexible seal 163 is formed from a high temperature alloy, such as an INCONEL alloy, for example, although any suitable material may be used to form the second flexible seal 163 as desired. A thickness of the second flexible seal 163 in the embodiment shown is approximately 0.040 inches (approximately ⅓ of a thickness of the second wing flange 162 ), although the second flexible seal 163 may have other thicknesses as desired. The second flexible seal 163 may be arcuate shaped to substantially correspond to the arcuate shape of the disc 120 when viewed axially. In the embodiment shown, the second flexible seal 163 has a convex side 167 facing the axial surface 156 of the inner shroud 117 . Also in the embodiment shown, the second flexible seal 163 extends into axially overlapping relationship to an inner surface 173 of a second shroud flange 174 . The reduced thickness of the first and second flexible seals 159 , 163 relative to the respective first and second wing flanges 164 , 162 contributes to flexing movement of the seals 159 , 163 in response to a centrifugal force applied during rotation of the disc 120 , as is additionally described below.
[0033] The first wing flange 154 , the first flexible seal 159 , the first shroud flange 166 , and the lip member 168 of the first shroud flange 166 cooperate to form a first labyrinth path between a gas passage 124 and a disc cavity 126 , as indicated by the dashed line 172 in FIG. 3 . The first wing flange 154 , the second wing flange 162 , the second flexible seal 163 , and the second shroud flange 174 cooperate to form a second labyrinth path between the gas passage 124 and the disc cavity 126 , as indicated by the dotted line 176 in FIG. 3 .
[0034] It should be noted that the surfaces of the wing member 144 , including the surfaces of the first and second wing flanges 154 , 162 and the surfaces of the first and second flexible seals 159 , 163 , may be hardened or coated with a hard material in order to prevent or reduce abrasion and wear of these surfaces in the event that rubbing contact occurs with adjacent stationary surfaces.
[0035] The sealing assembly 138 operates in a manner substantially similar to that described for the sealing assembly of the first embodiment. However, the flexible seals 159 , 163 operate to further restrict passage of gas, such as cooling air from the disc cavity 126 to the gas passage 124 . In particular, rotation of the disc 120 , and the resulting centrifugal force applied to the flexible seals 159 , 163 , causes the flexible seals 159 , 163 to move outwardly to locations closely adjacent to the distal end 170 of the first shroud flange 166 and the inner surface 173 of the second shroud flange 174 , respectively. Hence, the flexible seals 159 , 163 additionally restrict the flow area for the respective labyrinth paths 172 , 176 . It should also be noted that the flexible seal 163 provides an additional location for causing gas to change direction, i.e., 180 degrees, in order to pass between the disc cavity 126 and the third fluid chamber P 3
[0036] While FIGS. 1 and 2 illustrate the wing member 44 incorporated into the sides of the discs 20 and FIG. 3 illustrates the wing member 144 extending from the cover plate 147 , it should be understood that other configurations for supporting wing members may be provided. For example, wing members may be formed by being cast onto blade platforms and machined to desired specifications. In such a configuration, each blade platform may be provided with a separate wing member. Hence, it should be understood that although particular structure has been illustrated and described for supporting the wing members 44 , 144 to extend from the side of the disc 20 , 120 , as defined by either the disc structure itself or elements mounted to the side of the disc structure, other structure or additional structure for supporting the wing members 44 , 144 may be provided.
[0037] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention. | A disc seal assembly for use in a turbine engine. The disc seal assembly includes a plurality of outwardly extending sealing flange members that define a plurality of fluid pockets. The sealing flange members define a labyrinth flow path therebetween to limit leakage between a hot gas path and a disc cavity in the turbine engine. | 5 |
This invention claims priority to the provisional patent application entitled “Apparatus and Method for Rendering Synthetic Objects into Real Scenes”, Ser. No. 60/093,257, filed Jul. 17, 1998.
This invention was made with Government support under Grant No. FDN00014-96-1-1200 awarded by the Office of Naval Research (ONR BMDO). The Government has certain rights to this invention.
BRIEF DESCRIPTION OF THE INVENTION
This invention relates generally to computer graphics. More particularly, this invention relates to techniques for rendering synthetic objects into real scenes in a computer graphics context.
BACKGROUND OF THE INVENTION
The practice of adding new objects to photographs dates to the early days of photography in the simple form of pasting a cut-out from one picture onto another. While the technique conveys the idea of the new object being in the scene, it usually fails to produce an image that as a whole is a believable photograph. Attaining such realism requires a number of aspects of the two images to match. First, the camera projections should be consistent, otherwise the object may seem too foreshortened or skewed relative to the rest of the picture. Second, the patterns of film grain and film response should match. Third, the lighting on the object needs to be consistent with other objects in the environment. Lastly, the object needs to cast realistic shadows and reflections on the scene. Skilled artists found that by giving these considerations due attention, synthetic objects could be painted into still photographs convincingly.
In optical film compositing, the use of object mattes to prevent particular sections of film from being exposed made the same sort of cut-and-paste compositing possible for moving images. However, the increased demands of realism imposed by the dynamic nature of film made matching camera positions and lighting even more critical. As a result, care was taken to light the objects appropriately for the scene into which they were to be composited. This would still not account for the objects casting shadows onto the scene, so often these were painted in by artists frame by frame. Digital film scanning and compositing helped make this process far more efficient.
Global illumination work has recently produced algorithms and software to realistically simulate lighting in synthetic scenes, including indirect lighting with both specular and diffuse reflections. Some work has been done on the specific problem of compositing objects into photography. For example, there are known procedures for rendering architecture into background photographs using knowledge of the sun position and measurements or approximations of the local ambient light. For diffuse buildings in diffuse scenes, the technique can be effective. The technique of reflection mapping (also called environment mapping) produces realistic results for mirror-like objects. In reflection mapping, a panoramic image is rendered or photographed from the location of the object. Then, the surface normals of the object are used to index into the panoramic image by reflecting rays from the desired viewpoint. As a result, the shiny object appears to properly reflect the desired environment. (Using the surface normal indexing method, the object will not reflect itself. Correct self-reflection can be obtained through ray tracing). However, the technique is limited to mirror-like reflection and does not account for objects casting light or shadows on the environment.
A common visual effects technique for having synthetic objects cast shadows on an existing environment is to create an approximate geometric model of the environment local to the object, and then compute the shadows from various manually specified light sources. The shadows can then be subtracted from the background image. In the hands of professional artists this technique can produce excellent results, but it requires knowing the position, size, shape, color, and intensity of each of the scene's light sources. Furthermore, it does not account for diffuse reflection from the scene, and light reflected by the objects onto the scene must be handled specially.
Thus, there are a number of difficulties associated with rendering synthetic objects into real-world scenes. It is becoming particularly important to resolve these difficulties in the field of computer graphics, particularly in architectural and visual effects domains. Oftentimes, a piece of furniture, a prop, or a digital creature or actor needs to be rendered seamlessly into a real scene. This difficult task requires that the objects be lit consistently with the surfaces in their vicinity, and that the interplay of light between the objects and their surroundings be properly simulated. Specifically, the objects should cast shadows, appear in reflections, and refract, focus, and emit light just as real objects would.
Currently available techniques for realistically rendering synthetic objects into scenes are labor intensive and not always successful. A common technique is to manually survey the positions of the light sources, and to instantiate a virtual light of equal color and intensity for each real light to illuminate the synthetic objects. Another technique is to photograph a reference object (such as a gray sphere or a real model similar in appearance to the chosen synthetic object) in the scene where the new object is to be rendered, and use its appearance as a qualitative guide in manually configuring the lighting environment. Lastly, the technique of reflection mapping is useful for mirror-like reflections. These methods typically require considerable hand-refinement and none of them properly simulates the effects of indirect illumination from the environment.
Accurately simulating the effects of both direct and indirect lighting has been the subject of research in global illumination. With a global illumination algorithm, if the entire scene were modeled with its full geometric and reflectance (BRDF) characteristics, one could correctly render a synthetic object into the scene simply by adding to the model and re-computing the global illumination solution. Unfortunately, obtaining a full geometric and reflectance model of a large environment is extremely difficult. Furthermore, global illumination solutions for large complex environments are extremely computationally intensive.
Moreover, it seems that having a full reflectance model of the large-scale scene should be unnecessary: under most circumstances a new object will have no significant effect on the appearance of most of the distant scene. Thus, for such distant areas, knowing just its radiance (under the desired lighting conditions) should suffice.
The patent application entitled “Apparatus and Method for Recovering High Dynamic Range Radiance Maps from Photographs”, Ser. No. 09/126,631, filed Jul. 30, 1998, (hereinafter referred to as “the Debevec patent”) introduces a high dynamic range photographic technique that allows accurate measurements of scene radiance to be derived from a set of differently exposed photographs. The patent application is assigned to the assignee of the present invention and is incorporated by reference herein. The technique described in the patent application allows both low levels of indirect radiance from surfaces and high levels of direct radiance from light sources to be accurately recorded. When combined with image-based modeling and rendering techniques such as view interpolation, projective texture mapping, and possibly active techniques for measuring geometry, these derived radiance maps can be used to construct spatial representations of scene radiance.
The term light-based model refers to a representation of a scene that consists of radiance information, possibly with specific reference to light leaving surfaces, but not necessarily containing reflectance property (BRDF) information. A light-based model can be used to evaluate the 5D plenoptic function P(θ, φ, V x , V y , V z ,) for a given virtual or real subset of space, as described in Adelson, et al., “Computational Models of Visual Processing”, MIT Press, Cambridge, Mass., 1991, Ch. 1. A material-based model is converted to a light based model by computing an illumination solution for it. A light-based model is differentiated from an image-based model in that its light values are actual measures of radiance, whereas image-based models may contain pixel values already transformed and truncated by the response function of an image acquisition or synthesis process.
It would be highly desirable to provide a technique for realistically adding new objects to background plate photography as well as general light-based models. The synthetic objects should be able to have arbitrary material properties and should be able to be rendered with appropriate illumination in arbitrary lighting environments. Furthermore, the objects should correctly interact with the environment around them; that is, they should cast the appropriate shadows, they should be properly reflected, they should reflect and focus light, and they should exhibit appropriate diffuse inter-reflection. Ideally, the method should be carried out with commonly available equipment and software.
SUMMARY OF THE INVENTION
A method of placing an image of a synthetic object into a scene includes the step of establishing a recorded field of illumination that characterizes variable incident illumination in a scene. A desired position and orientation of a synthetic object is specified within the scene with respect to the recorded field of illumination. A varying field of illumination caused by the synthetic object is identified within the scene. Synthetic object reflectance caused by the synthetic object is simulated in the scene. The synthetic object is then constructed within the scene using the varying field of illumination and the synthetic object reflectance.
The technique of the invention allows for one or more computer generated objects to be illuminated by measurements of illumination in a real scene and combined with existing photographs to compute a realistic image of how the objects would appear if they actually had been photographed in the scene, including shadows and reflections on the scene.. A photographic device called a light probe is used to measure the full dynamic range of the incident illumination in the scene. An illumination technique (for example, a global illumination technique) is used to illuminate the synthetic objects with these measurements of real light in the scene. To generate the image of the objects placed into the scene, the invention partitions the scene into three components. The first is the distant scene, which is the visible part of the environment too remote to be perceptibly affected by the synthetic object. The second is the local scene, which is the part of the environment that will be significantly affected by the presence of the objects. The third component is the synthetic objects. The illumination algorithm is used to correctly simulate the interaction of light amongst these three elements, with the exception that light radiated toward the distant environment will not be considered in the calculation. As a result, the reflectance characteristics of the distant environment need not be known—the technique uses reflectance characteristics only for the local scene and the synthetic objects. The challenges in estimating the reflectance characteristics of the local scene are addressed through techniques that result in usable approximations. A differential rendering technique produces perceptually accurate results even when the estimated reflectance characteristics are only approximate. The invention also allows real objects and actors to be rendered into images and environments in a similar manner by projecting the measured illumination onto them with computer-controlled light.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which:
FIG. 1 illustrates the processing steps associated with an embodiment of the invention.
FIG. 2 illustrates the operation of acquiring a background photograph in accordance with an embodiment of the invention.
FIG. 3 illustrates the operation of using a light probe in accordance with an embodiment of the invention.
FIG. 4 illustrates the construction of a light based model in accordance with an embodiment of the invention.
FIG. 5 illustrates the operation of computing a global illumination solution in accordance with an embodiment of the invention.
FIG. 6 illustrates an apparatus that may be used to implement the method of the invention.
Like reference numeral refer to corresponding parts throughout the drawings.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates the processing steps associated with an embodiment of the invention. As shown in the figure, a scene is partitioned into three components. The first is the distant scene 20 , which is the visible part of the environment too remote to be perceptibly affected by the synthetic object. The second is the local scene 22 , which is the part of the environment which will be significantly affected by the presence of the objects. The third component is the synthetic object or objects 24 .
Global illumination is used to correctly simulate the interaction of light amongst these three elements, with the exception that light radiated toward the distant environment will not be considered in the calculation. As a result, the BRDF of the distant environment need not be known—the technique uses BRDF information only for the local scene and the synthetic objects.
The method of the invention is disclosed in connection with the specific case of rendering synthetic objects into particular views of a scene (such as background plates) rather than into a general image-based model. In this method, a light probe is used to acquire a high dynamic range panoramic radiance map near the location where the object will be rendered. A simple example of a light probe is a camera aimed at a mirrored sphere, a configuration commonly used for acquiring environment maps. An approximately geometric model of the scene is created (via surveying, photogrammetry, or 3D scanning with lasers or structured light) and mapped with radiance values measured with the light probe. The distant scene, local scene, and synthetic objects are rendered with global illumination from the same point of view as the background plate, and the results are composited into the background plate with a differential rendering technique.
The invention is disclosed by addressing the following topics. Attention initially turns to the basic technique of using acquired maps of scene radiance to illuminate synthetic objects. Next, the general method of rendering synthetic objects into real scenes is described. Afterwards, a practical technique based on this method using a light probe to measure incident illumination is described. Subsequently, a discussion ensues regarding a differential rendering technique for rendering the local environment with only an approximate description of its reflectance. A simple method to approximately recover the diffuse reflectance characteristics of the local environment is then discussed.
Ideally, computer-generated objects are lit by actual recordings of light from the scene, using global illumination or a related computer graphics illumination technique, such as radiosity or ray-tracing. Performing the lighting in this manner provides a unified and physically accurate alternative to manually attempting to replicate incident illumination conditions.
Accurately recording light in a scene is difficult because of the high dynamic range that scenes typically exhibit; this wide range of brightness is the result of light sources being relatively concentrated. As a result, the intensity of a source is often two to six orders of magnitude (i.e., from one hundred to one million times) larger than the intensity of the non-emissive parts of an environment. However, it is necessary to accurately record both the large areas of indirect light from the environment and the concentrated areas of direct light from the sources since both are significant parts of the illumination solution.
Using the technique of the previously cited Debevec patent, one can acquire correct measures of scene radiance using conventional imaging equipment. The images, called radiance maps, are derived from a series of images with different sensor integration times and a technique for computing and accounting for the imaging system response function ƒ. These measures are used to illuminate synthetic objects exhibiting arbitrary material properties. New digital photographic methods are also able to achieve high dynamic range via logarithmic (or similarly nonlinear) response image sensor elements.
A high-dynamic range lighting environment with, for example, electric, natural, and indirect lighting can be obtained by taking a full dynamic range photograph of a mirrored ball on a table. Alternate techniques to acquire an omni-direction view of the scene involve using fisheye lenses, or by using a mosaic of photographs looking in different directions, by scanning the scene with a linear image sensor, or by photographing a curved mirror of non-spherical shape. In other words, an omni-directional high dynamic range illuminated scene may be acquired by a series of images with varying exposure amounts, by a series of images from electronic imaging devices aimed in different directions, from a series of images from digital cameras aimed in different directions, a wide angle refractive lens system, or from a reflective curved object covering a wide field of view.
A digital camera can be used to acquire a series of images in, for example, two-stop exposure increments from ¼ to {fraction (1/1000)} second. The images may then be fused using the technique described in the previously cited Debevec patent application. A single low-dynamic range photograph would be unable to record the correct colors and intensities over the entire scene. However, using the technique of the Debevec patent, recovered RGB radiance values for all the points in the scene including the light sources can be achieved.
Attention now turns to extending the technique of using radiance maps to illuminate synthetic objects to a technique of computing the proper photometric interaction of the objects with the scene. How high dynamic range photography and image-based modeling combine in a natural manner to allow the simulation of arbitrary (non-infinite) lighting environments is also discussed.
Adding new objects to light-based scene representations also involves partitioning a scene into three parts: the distant scene, the local scene, and the synthetic objects. The geometric and photometric requirements for each of these components can be described as follows.
A light-based model is used for the distant scene. The distant scene is constructed as a light-based model. The synthetic objects will receive light from this model, so it is necessary that the model store true measures of radiance rather than low dynamic range pixel values from conventional images. The light-based model can take on any form, using very little explicit geometry, some geometry, moderate geometry, or be a full 3D scan of an environment with view-dependent texture-mapped radiance. What is important is for the model to provide accurate measures of incident illumination in the vicinity of the objects, as well as from the desired viewpoint. The discussion below presents a convenient procedure for constructing a minimal model that meets these requirements.
In the illumination computation, the distant scene radiates light toward the local scene and the synthetic objects, but ignores light reflected back to it. It is assumed that no area of the distant scene will be significantly affected by light reflecting from the synthetic objects; if that were the case, the area should instead belong to the local scene, which contains the BRDF information necessary to interact with light.
An approximate material-based model of the local scene is then established. The local scene consists of the surfaces that will photometrically interact with the synthetic objects in a visually significant manner. It is this geometry onto which the objects will cast shadows and reflect light. Since the local scene needs to fully participate in the illumination solution, both its geometry and reflectance characteristics should be known, at least approximately. If the geometry of the local scene is not readily available with sufficient accuracy from the light-based model of the distant scene, there are various techniques available for determining its geometry through active or passive methods. In the common case where the local scene is a flat surface that supports the synthetic objects, its geometry is determined easily from the camera pose.
Usually, the local scene will be the part of the scene that is geometrically close to the synthetic objects. When the local scene is mostly diffuse, the rendering equation shows that the visible effect of the objects on the local scene decreases as the inverse square of the distance between the two. Nonetheless, there are a variety of circumstances in which synthetic objects can significantly affect areas of the scene not in the immediate vicinity. Some common circumstances are:
If there are concentrated light sources illuminating the object, then the object can cast a significant shadow on a distant surface collinear with it and the light source. If there are concentrated light sources and the object is flat and specular, it can focus a significant amount of light onto a distant part of the scene. If a part of the distant scene is flat and specular (e.g. a mirror on a wall), its appearance can be significantly affected by a synthetic object.
If the synthetic object emits light (e.g. a synthetic laser), it can affect the appearance of the distant scene significantly.
These situations should be considered in choosing which parts of the scene should be deemed local and which parts distant. Any part of the scene that will be significantly affected in its appearance from the desired viewpoint should be included as part of the local scene.
Since the local scene is a full BRDF model (that is, it is imbued with surface reflectance characteristics), it can be added to the illumination computation as would any other object. The local scene may consist of any number of surfaces and objects with different material properties. For example, the local scene could consist of a patch of floor beneath the synthetic object to catch shadows as well as a mirror surface hanging on the opposite wall to catch a reflection. The local scene replaces the corresponding part of the light-based model of the distant scene.
Since it can be difficult to determine the precise BRDF characteristics of the local scene, it is often desirable to have only the change in the local scene's appearance be computed with the BRDF estimate; its appearance due to illumination from the distant scene is taken from the original light-based model. This differential rendering method is presented below.
Complete material-based models of the objects must also be considered. The synthetic objects themselves may consist of any variety of shapes and materials supported by the global illumination software, including plastics, metals, emitters, and dielectrics such as glass and water. They should be placed in their desired geometric correspondence to the local scene.
Once the distant scene, local scene, and synthetic objects are properly modeled and positioned, the global illumination software can be used in the normal fashion to produce renderings from the desired viewpoints.
Attention now turns to the operation of compositing with the use of the light probe. This section presents a particular technique for constructing a light-based model of a real scene suitable for adding synthetic objects at a particular location. This technique is useful for compositing objects into actual photography of a scene.
It was previously mentioned that the light-based model of the distant scene needs to appear correctly in the vicinity of the synthetic objects as well as from the desired viewpoints. This latter requirement can be satisfied if it is possible to directly acquire radiance maps of the scene from the desired viewpoints. The former requirement, that they appear photometrically correct in all directions in the vicinity of the synthetic objects, arises because this information comprises the incident light which will illuminate the objects.
To obtain this part of the light-based model, one acquires a full dynamic range omnidirectional radiance map near the location of the synthetic object or objects. One technique of acquiring this radiance map is to photograph a spherical first-surface mirror, such as a polished steel ball, placed at or near the desired location of the synthetic object. FIG. 2 illustrates a set-up to acquire the background of a photograph. FIG. 2 includes a camera 26 and a set of objects 28 . FIG. 3 illustrates a set-up for a light probe. In particular, the figure illustrates a camera 26 , a set of objects 28 , and a reflective ball 30 .
The radiance measurements observed in the ball 30 are mapped onto the geometry of the distant scene. In many circumstances this model can be very simple. In particular, if the objects are small and resting on a flat surface, one can model the scene as a horizontal plane for the resting surface and a large dome for the rest of the environment. FIG. 4 illustrates the image from the ball 30 mapped onto a table surface and the walls and ceiling of a finite room
The next step is to map from the probe to the scene model. To precisely determine the mapping between coordinates on the ball and rays in the world, one needs to record the position of the ball 30 relative to the camera 26 , the size of the ball 30 , and the camera parameters such as its location in the scene and focal length. With this information, it is straightforward to trace rays from the camera center through the pixels of the image, and reflect rays off the ball into the environment. Often a good approximation results from assuming the ball is small relative to the environment and that the camera's view is orthographic.
The data acquired from a single ball image will exhibit a number of artifacts. First, the camera 26 (and possibly the photographer) will be visible. The ball 30 , in observing the scene, interacts with it, the ball (and its support) can appear in reflections, cast shadows, and can reflect light back onto surfaces. Lastly, the ball will not reflect the scene directly behind it, and will poorly sample the area nearby. If care is taken in positioning the ball and camera, these effects can be minimized and will have a negligible effect on the final renderings. If the artifacts are significant, the images can be fixed manually in image editing program or by selectively combining images of the ball taken from different directions. It has been observed that combining two images of the ball taken ninety degrees apart from each other allows one to eliminate the camera's appearance and to avoid poor sampling.
To render the objects into the scene, a synthetic local scene model is created. Images of the scene from the desired viewpoint(s) are taken, for example as shown in FIG. 2, and their position relative to the scene is recorded through pose-instrumented cameras or photogrammetry. The location of the ball in the scene is also recorded at this time. The global illumination software is then run to render the objects, local scene, and distant scene from the desired viewpoint, as shown in FIG. 5 .
The objects and local scene are then composited onto the background image. To perform this compositing, a mask is created by rendering the objects and local scene in white and the distant scene in black. If objects in the distant scene (which may appear in front of the objects or local scene from certain viewpoints) are geometrically modeled, they will properly obscure the local scene and the objects as necessary. This compositing can be considered as a subset of the general method wherein the light-based model of the distant scene acts as follows: if (V z , V y , V x ,) corresponds to an actual view of the scene, return the radiance value looking in direction (θ, φ). Otherwise, return the radiance value obtained by casting the ray (θ, φ, V z , V y , V x ,) onto the radiance-mapped distant scene model.
In the next section a more robust method of compositing the local scene into the background image is described. The method presented so far requires that the local scene be modeled accurately in both its geometry and its spatially varying material properties. If the model is inaccurate, the appearance of the local scene will not be consistent with the appearance of an adjacent distant scene.
Suppose that an illumination solution is computed for the local and distant scene models without including the synthetic objects. If the BRDF and geometry of the local scene model were perfectly accurate, then one would expect the appearance of the rendered local scene to be consistent with its appearance in the light-based model of the entire scene. Call the appearance of the local scene from the desired viewpoint in the light-based model LS b , which is simply the background image. Let LS noobl denote the appearance of the local scene, without the synthetic objects, as calculated by the global illumination solution. The error in the rendered local scene (without the objects) is thus: Err 18 =LS noobl −LS b . This error-results from the difference between the BRDF characteristics of the actual local scene as compared to the modeled local scene.
Let LS obj denote the appearance of the local environment as calculated by the global illumination solution with the synthetic objects in place. The error can be compensated if the final rendering LS final is computed as:
LS final =LS obj −Err 18
Equivalently, one can write:
LS final =LS b +( LS obj −LS noobl )
In this form, it can be observed that whenever LS obj and LS noobl are the same (i.e. the addition of the objects to the scene had no effect on the local scene) the final rendering of the local scene is equivalent to LS b (e.g. the background plate). When LS obj is darker than LS noobl light is subtracted from the background to form shadows, and when LS obj is lighter than LS noobl light is added to the background to produce reflections and caustics.
Stated more generally, the appearance of the local scene without the objects is computed with the correct reflectance characteristics lit by the correct environment, and the change in appearance due to the presence of the synthetic objects is computed with the modeled reflectance characteristics as lit by the modeled environment. While the realism of LS final still benefits from having a good model of the reflectance characteristics of the local scene, the perceptual effect of small errors in albedo or specular properties is considerably reduced.
It is important to stress that this technique can still produce arbitrarily wrong results depending on the amount of error in the estimated local scene BRDF and the inaccuracies in the light-based model of the distance scene. In fact, Err 18 may be larger than LS obj , causing LS final to be negative. An alternate approach is to compensate for the relative error in the appearance of the local scene: LS final =L sb (LS obj/LS noobl ). Inaccuracies in the local scene BRDF will also be reflected in the objects.
Techniques for estimating the BRDF of the local scene will now be described. Simulating the interaction of light between the local scene and the synthetic objects requires a model of the reflectance characteristics of the local scene. Recent work has presented methods for measuring the reflectance properties of materials through observation under controlled lighting configurations. Furthermore, reflectance characteristics can also be measured with commercial radiometric devices.
It would be more convenient if the local scene reflectance could be estimated directly from observation. Since the light-based model contains information about the radiance of the local scene as well as its irradiance, it actually contains information about the radiance of the local scene as well as its irradiance, it actually contains information about the local scene reflectance. If reflectance characteristics for the local scene are hypothesized, the local scene can be illuminated with its known irradiance from the light-based model. If the hypothesis is correct, then the appearance should be consistent with the measured appearance. This suggests the following iterative method for recovering the reflectance properties of the local scene:
1. Assume a reflectance model for the local scene (e.g. diffuse only, diffuse+specular, metallic or arbitrary BRDF, including spatial variation).
2. Choose approximate initial values for the parameters of the reflectance model.
3. Compute a global illumination solution for the local scene with the current parameters using the observed lighting configuration or configurations.
4. Compare the appearance of the rendered local scene to its actual appearance in one or more views.
5. If the renderings are not consistent, adjust the parameters of the reflectance model and return to step 3.
Assuming a diffuse-only model of the local scene in step 1 makes the adjustment in step 5 straightforward, one has:
L rl (θ r, φr )=∫ 0 2π ∫ 0 π/2 ρ d L i (θ i , φ i ) cos θ i sinθ i dθ i dφ i =ρ 2 ∫ 0 2π ∫ 0 π/2 (θ i ,φ i ) cosθ i sinθ i dθ i dφ i
If the local scene is initialized to be perfectly diffuse (ρ d =1) everywhere, one has:
L r2 (θ r , φ r )=∫ 0 2π ∫ 0 π/2 L i (θ i , φ i ) cosθ i sinθ i dθ i dφ i
The updated diffuse reflectance coefficient for each part of the local scene can be computed as: ρ ′ d = L r1 ( θ r , φ r ) L r2 ( θ r , φ r )
In this manner we use the global illumination calculation to render each patch as a perfectly diffuse reflector and compare the resulting radiance to the observed value. Dividing the two quantities yields the next estimate of the diffuse reflection coefficient ρ 1 d . Thus, diffuse reflectance characteristics of a scene are determined by dividing the measured amount of radiance leaving a surface within the scene by the cosine-weighted integral of the incident radiance at the surface.
If there is no inter-reflection within the local scene, then the ρ d estimates will make the renderings consistent. If there is inter-reflection, then the algorithm should be iterated until there is convergence. For a trichromatic image, the red, green, and blue diffuse reflectance values are computed independently. In the standard “plastic” illumination model, just two more coefficients—those for specular intensity and roughness—need to be specified.
In sum, a technique for adding new objects to light-based models with correct illumination has been described. The method leverages a technique of using high dynamic range images of real scene radiance to synthetically illuminate new objects with arbitrary reflectance characteristics. This technique is leveraged in a technique to simulate interplay of light between synthetic objects and the light-based environment, including shadows, reflections, and caustics. The method can be implemented with standard global illumination techniques.
For the particular case of rendering synthetic objects into real scenes (rather than general light-based models), a practical instance of the method that uses a light probe to record incident illumination in the vicinity of the synthetic objects is presented. In addition, a differential rendering technique is described that can convincingly render the interplay of light between objects and the local scene. An interactive approach was presented for determining reflectance characteristics of the local scene based on measured geometry and observed radiance in uncontrolled lighting conditions.
The technique of the invention allows synthetic objects to be realistically rendered into real scenes with correct lighting. A variant of the technique can be used to render real objects, such as real actors or actual product samples, into a real scene. For synthetic objects, the computer computes the appearance of the synthetic object under the measured illumination of the scene. For a real object, it is illuminated directly using an apparatus to project a field of light onto it using a computer-controlled bank of illumination. The object is then photographed, and when isolated from the photograph using a matte extraction technique, the object is composited into the scene as would a synthetic object in the technique described earlier. The computer-controlled bank of lighting takes on at least two forms. One is an array of lights of different colors positioned around and pointing toward the real object or actor. Another is an image projection device, such as a digital light projector aimed or focused at the person or object using a mirror. In either case, the light projection device is used to project onto the real person or object the appropriate illumination as recorded at the desired scene to be rendered into. Note finally that the image of the person or object under the desired illumination can be constructed by taking a linear combination of its appearance under a set of basis lighting configurations.
FIG. 6 illustrates an apparatus 50 that may be used to implement the method of the invention. The apparatus 50 includes standard computer components of a central processing unit 52 , a memory 54 , and a system bus 56 for data communication between the central processing unit 52 and the memory 54 . The memory 54 stores an executable program, namely a synthetic object insertion program 60 that has executable instructions to implement the techniques described herein. The synthetic object insertion program 60 operates on image data received through input/output devices 62 connected to an image acquisition device 64 . The result of the processing of the synthetic object insertion program 60 is an image with an inserted synthetic object 66 .
The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. In other instances, well known circuits and devices are shown in block diagram form in order to avoid unnecessary distraction from the underlying invention. Thus, the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following Claims and their equivalents. | A method of placing an image of a synthetic object into a scene includes the step of establishing a recorded field of illumination that characterizes variable incident illumination in a scene. A desired position and orientation of a synthetic object is specified within the scene with respect to the recorded field of illumination. A varying field of illumination caused by the synthetic object is identified within the scene. Synthetic object reflectance caused by the synthetic object is simulated in the scene. The synthetic object is then constructed within the scene using the varying field of illumination and the synthetic object reflectance. | 6 |
BACKGROUND OF THE INVENTION
The present invention relates to a level shift circuit and more particularly to a small signal level shift circuit for shifting the level of a small signal without distortion.
Generally, in circuits or devices for processing a signal generated from a signal source such as a sensor, a monitoring circuit, a signal generating circuit and a level sensing circuit, etc., the levels of the generated signals required in the above circuits are different. A signal level is shifted by a level required in a level shift circuit shown in FIG. 1. In FIG. 1, the collector terminal of transistor 2 is coupled to a power source voltage Vcc, its base terminal is coupled to a signal Vs generated from a signal source, and its emitter terminal is grounded through serially connected resistors 4 and 6, thereby obtaining an output signal Vo at a node between the resistors 4 and 6. If a signal Vs such as FIG. 2A is supplied to the base terminal of the transistor 2, the transistor 2 amplifies the signal Vs. At this time, at the node between resistors 4 and 6, a level shifted signal Vo such as FIG. 2B is generated by adding the amplified signal to a signal level obtained by dividing the power source voltage Vcc. Accordingly, the signal Vs is shifted by a predetermined voltage level V SET .
As described above, the conventional level shift circuit generates the following problems according to the use of transistor. First, when a signal level is shifted largely, a transistor having a large small-signal current amplification rate h fe should be used. But, in this case, noise level is also increased, thereby generating a false operation, so that an extra circuit for preventing the false operation is needed. Secondly, when the signal level is very low, the transistor is in a cut-off region, so that the transistor does not operate. Thirdly, distortion caused by several operation characteristics of transistor is generated.
Meanwhile, in a switching mode power supply (hereinafter referred to as SMPS) widely used as power supply of several electric or electronic devices, signal transfer is needed, which is described in detail as follows. With reference to FIG. 3 showing an example of multi-output SMPS, a schematic operation useful for understanding of the present invention is described. An input rectifying circuit 12 rectifies an AC (alternating current) power source through an AC input power source 10 and supplies the rectified power source to a transformer 14 and a switching control unit 16. Generally, as the switching control unit 16, one-chip IC such as UC1842 which is a PWM controller of UNITRODE company in U.S.A. is used. The switching control, unit 16 is operated by the DC (direct current) power source supplied from the input rectifying circuit 12, thereby generating a pulse width modulation (hereinafter referred to as PWM) signal having a predetermined frequency. A switching circuit 18 coupled between a primary side of the transformer 14 and the switching control unit 16 induces power source at a secondary side of the transformer 14, by switching the DC power source supplied to the primary side of the transformer 14 in response to the PWM signal. The induced power source is rectified and smoothed in first and second output rectifying circuits 22 and 24, and then is supplied to a load through first and second DC output power sources 26 and 28, respectively. An insulating circuit 30 and a feedback circuit 32 feed back the output power source voltage of the second DC power source 28 to the switching control portion 16. According, the switching control unit 16 varies duty of PWM signal according, to the state of feedback voltage, thereby stabilizing the output power source.
And, a current sensing circuit 20 senses the state of the primary side current flowing through the switching unit 18 and supplies the sensed current state to the switching control unit 16. At this time, if current over a regulated value is sensed due to abnormality of input power source or the abnormality of load or SMPS, the switching control unit 16 is shut down, thereby stopping the generation of PWM signal to protect load or SMPS from overcurrent.
FIG. 4 is a diagram of a conventional current sensing circuit for sensing a current state of primary side as described above, where a switching control unit 16, a switching unit 18, a current sensing circuit 20, and lines 101 to 104 correspond to the corresponding circuits of the FIG. 3, respectively. The switching control unit 16 is constituted by a PWM controller as described above. A field effect transistor (hereinafter referred to as FET) 36 of the switching unit 18 switches a primary-side power source in response to a PWM signal, such as that of FIG. 5A, outputted from an output terminal OUTPUT of the switching control unit 16. In the line 101 which is a primary side of transformer 14, a voltage waveform such as FIG. 5B is shown by the FET 36. Resistors 32 and 34 are coupled between the output terminal OUTPUT of the switching control unit 16 and a gate terminal of the FET 36, to properly set on/off time of FET 36. A resistor 42 of the current sensing circuit 20 is a current sensing resistor, which limits current flowing through the FET 36 and at the same time, generates a voltage corresponding to the amount of current in the line 103. The generated voltage shows a waveform such as FIG. 5C and is supplied to a current sensing terminal I SENSE of the switching control unit 16 through a resistor 40 as a current sensing voltage having the waveform such as FIG. 5D.
Generally, a shut-down voltage where the switching control unit 16 senses overcurrent and is shut down is set as 1 V, and accordingly, a current sensing resistance Rs according to a maximum current Ismax for sensing overcurrent is determined by the following equation (1):
Ismax˜1.0V/Rs (1)
Thus, if a current sensing voltage supplied to the current sensing terminal I SENSE of the switching control unit 16 through the resistor 40 reaches 1 V as the current passing through the FET 36 increases, the switching control unit 16 is shut down. At this time, since power proportional to the current flowing through the FET 36 is consumed on the resistor 42, heat loss is generated. For instance, when a maximum current Ismax where the current sensing voltage becomes 1 V, is 15A, a duty D of PWM signal is 0.8, and a resistance R 42 of resistor 42 is 65 mΩ, the power consumption Pt is given by the following equation (2): ##EQU1##
That is, to obtain the current sensing voltage of 1V, loss of 11.7 W is generated. Accordingly, when large current such as 15A is sensed, excessive heat loss is generated, so that additional radiating processing is required. Also, there is a problem in that the efficiency of SMPS is deteriorated by the generation of heat loss. Also, the resistor 42 should be a resistor having rated dissipation which is sufficiently large with respect to the power of 11.7 W, so that there are problems of occupying large space and raising the cost.
Accordingly, another current sensing circuit constituted by a transformer (troidal core transformer) 44 for sensing current by a magnetic element instead of the resistor 42, as shown in FIG. 6 is used. In FIG. 6, the switching control unit 16, the switching unit 18, the current sensing circuit 20, and the lines 101 to 104 correspond to the corresponding circuits of FIGS. 3 and 4, respectively. And, the switching unit 18 switches the primary-side power source in response to a PWM signal, such as FIG. 7A, outputted from the switching control unit 16 as described above. Then, the voltage waveform such as FIG. 7B is shown in the line 101. A resistor 46 converts magnetic current induced in the secondary side of the transformer 44 into a voltage, which is generated with the waveform such as FIG. 7C in the line 105. The voltage of the line 105 appears in the line 106 without negative voltage, as shown in FIG. 7D, through a diode 48, and is supplied to the current sensing terminal I SENSE of the switching control unit 16 through the resistor 52 as a current sensing voltage having the waveform such as FIG. 7E. A resistor 50 stabilizes the voltage of the line 106.
In this case, the power proportional to the current flowing through the switching unit 18 is consumed also in the resistor 46, so that heat loss is generated. For instance, when a maximum magnetic current Imax where the current sensing voltage becomes 1 V, is 150 mA and a resistance R 46 of resistor 46 is 15Ω, the maximum voltage V 105 in the line 105 is given by the following equation (3):
i V.sub.105 =150×10.sup.-3 ×15=2.25V (3)
Thus, when the duty D of PWM signal is 0.8, the power consumption Pt dissipated in the resistor 46 is given by the following equation (4): ##EQU2##
That is, the loss of 270 mW which is greatly reduced compared with the circuit of FIG. 4 is generated to obtain the current sensing voltage of 1 V. However, according to the use of magnetic element, the following problems are generated. First, the number of steps in manufacturing of products is increased and the automatic insert machine cannot be used. Secondly, in the design of the magnetic element, saturation of magnetic core should be considered, so that its realization is difficult.
As described above, in SMPS, since the conventional current sensing circuit uses a resistor element or a magnetic element to sense current state, the above-mentioned problems are generated and also there is another problem of causing a false operation since noise level with respect to large current is transferred as a current sensing voltage, as it is, during the transfer of current sensing voltage.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a small signal level shift circuit which can solve the aforementioned problems.
It is another object of the present invention to provide a small signal level shift circuit which can exactly and precisely control a device by shifting a small signal by a predetermined level without distortion.
It is still another object of the present invention to provide a small signal level shift circuit which can prevent a false operation of a device by reducing noise level generated during transmitting signal.
It is yet another object of the present invention to provide a small signal level shift circuit which can minimize heat loss by controlling the sensing of large current only by a small signal, in a current sensing circuit of SMPS.
It is yet still another object of the present invention to provide a small signal level shift circuit which can sense current without using a resistor element or a magnetic element having large rated dissipation.
(*To achieve the objects, the present invention comprises signal coupling means for DC-coupling a signal generated from a signal source and level shift means for shifting the DC-coupled signal by a predetermined shift level.*)
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:
FIG. 1 is a conventional level shift circuit;
FIGS. 2A and 2B are waveforms according to operation of FIG. 1;
FIG. 3 is a block diagram of a general switching mode power supply;
FIG. 4 is a current sensing circuit according to a conventional embodiment;
FIGS. 5A to 5D are waveforms at the respective circuits of FIG. 4;
FIG. 6 is a current sensing circuit according to another conventional embodiment;
FIGS. 7A to 7E are waveforms at the respective circuits of FIG. 6;
FIG. 8 is a level shift circuit of an embodiment according to the present invention;
FIGS. 9A and 9B are waveforms of FIG. 8 according to the present invention;
FIG. 10 is a level shift circuit of another embodiment according to the present invention;
FIG. 11 is a circuit diagram as an example where the level shift circuit according to the present invention is applied to that of FIG. 3; and
FIGS. 12A to 12D are waveforms at the respective circuit of FIG. 11 according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 8, resistors 62 and 64 are serially coupled between a power source voltage Vcc and a ground, and constantly divide the power source voltage Vcc. A capacitor 60 which is a capacitive element is coupled between a signal source Vs and a connection point of the resistors 62 and 64, and DC-couples the signal Vs. An output signal Vo is obtained at the connection point of the resistors 62 and 64.
An operational example of FIG. 8 is described with reference to the waveform view of FIG. 9 as follows. Assuming that the signal Vs generated from a signal source is such as that of FIG. 9A, the signal Vs appears as a level-shifted signal Vo such as FIG. 9B by being shifted by a shift level set by resistors 62 and 64 through the capacitor 60. That is, the signal Vs is shifted to a set voltage level V SET . The shift level V SFT is given by the following equation (5) according to resistances R 62 and R 64 of resistors 62 and 64. That is,
V.sub.SFT ={R.sub.64 /(R.sub.62 +R.sub.64)}×Vcc (5)
And, the level shifted output signal Vo is given by the following equation (6):
Vo=Vs+{R.sub.64 /(R.sub.62 +R.sub.64)}×Vcc (6)
Accordingly, when the output signal Vo is equal to or smaller than the power source voltage Vcc, the resistances of resistors 62 and 64 can be adjusted, thereby shifting the level of signal Vs to a desired level. As described above, the circuit of FIG. 8 does not amplify the level of signal Vs generated from a signal source and shifts only the level, so that the distortion of signal or the increase of noise level is prevented, thereby preventing a false operation of device. Also, the signal Vs of a very small level can be shifted. Here, the capacitor 60 performs the DC cut-off between the signal source and the resistors 62 and 64, thereby preventing the shift level voltage from being supplied to the signal source.
FIG. 10 is a level shift circuit of another embodiment according to the present invention, which is an example of replacing the capacitor 60 of FIG. 8 by a diode 66 which is a DC cut-off element. Accordingly, the resistors 62 and 64 are the same as those of FIG. 8, and the diode 66 is forwardly coupled to a connection point between resistors 62 and 64 from the signal source Vs. Accordingly, the diode 66 performs the DC-cut off of the signal source side from the resistors 62 and 64, thereby preventing the shift level voltage from being supplied to the signal source side.
Meanwhile, FIG. 11 shows an example where the level shift circuit of FIG. 8 according to the present invention is applied in the current sensing circuit 20 of SMPS shown in FIG. 3. In FIG. 11, a resistor 70 is coupled between the switching unit 18 and a ground. The resistor 70 is a current sensing resistor, which converts the current flowing through the switching unit 18 into a voltage of level corresponding to the current. A capacitor 72 is coupled between a connection point of switching unit 18 and resistor 70, and a connection point of resistors 74 and 76, and DC-couples the converted voltage level. The resistors 74 and 76 are serially coupled between a reference voltage terminal Vref of the switching control unit 16 and a ground, and constantly divide the reference voltage to set a shift level. Also, the connection point of resistors 74 and 76 are coupled between the capacitor 72 and a current sensing terminal I SENSE of the switching control unit 16. Here, the level shift circuit 78 having the capacitor 72 and the resistors 74 and 76 corresponds to that of FIG. 8. The switching control unit 16, the switching unit 18, the current sensing circuit 80 and the lines 101 to 104 correspond to the corresponding circuits of FIGS. 3 and 4 described above, respectively.
In FIG. 11, contrarily to the conventional one, the resistance of resistor 70 is set to a very small value, thereby generating in the line 103 a small voltage level, which is shifted by the shift level through the capacitor 72, and then is supplied to the current sensing terminal I SENSE of the switching control unit 16 as a current sensing voltage.
Meanwhile, a reference voltage Vref of generally 5.1 V (±1%) is generated in a reference voltage terminal Vref of the switching control unit 16. Accordingly, assuming that the shut-down voltage of the switching control unit 16 is set to 1.0 V as described above, for example, the shift level is set to 0.95 V. In this state, if the current sensing voltage of line 103 generated in the resistor 70 reaches 0.05 V, it becomes 1.0 V by being shifted by the shift level 0.95 V through the capacitor 72, and is supplied to the current sensing terminal I SENSE of the switching control unit 16. Accordingly, the switching control unit 16 senses overcurrent state and is shut down, thereby stopping the generation of PWM signal to protect the load or SMPS from overcurrent. Here, when the PWM signal outputted in the switching control unit 16 is identical to that of FIG. 12A, voltage waveform such as FIG. 12B appears in the line 101, and voltage waveform such as FIG. 12C appears by the resistor 70 in the line 103. The voltage of the line 103 is shifted by the shift level, and is generated in line 104 as a current sensing voltage such as FIG. 12D. At this time, if it is assumed that the maximum current Ismax where the current sensing voltage becomes 1 V is set to be 15A as shown in FIG. 4, the resistance R 70 of the resistor 70 is determined as 50 mV/15 A=3.3 mΩ. In this state, when the duty D of PWM signal is 0.8 as in the above case, the power consumption Pt of the resistor 70 is given by the following equation (7): ##EQU3##
That is, to obtain the current sensing voltage of 1 V, the loss of 0.6 W is generated, so that the loss is greatly reduced, compared with the aforementioned circuit of FIG. 4. Accordingly, even if large current is sensed, the heat loss is minimized, thereby improving the efficiency of SMPS, and the current can be sensed without using a resistor element or a magnetic element of rated dissipation. Moreover, noise level is reduced, and also, current can be exactly and precisely limited without distortion.
While the aforementioned description of the present invention describes a preferred embodiment, several variations can be made without departing from the spirit of the invention. Particularly, FIG. 8 illustrates that the shift level is set using only two resistors 62 and 64, but the shift level can be set by dividing a power source voltage Vcc by a plurality of resistors, and can be differently set using a variable resistor as shown in FIG. 8, if necessary. Similarly, only one capacitor 60 of FIG. 8 or one diode of FIG. 10 is used in the present invention, but a plurality of capacitors or diodes can be used if necessary, and other capacitive element or one-directional DC cut off means can be used. **Also, FIG. 11 illustrates that a shift level is set from a reference voltage of switching control unit 16. But, the shift level can be set by dividing a power source voltage as shown in FIG. 8 and instead of using the level shift circuit of FIG. 8, that of FIG. 10 can be used to obtain the same effect.
As described above, according to the present invention, a variation of small signal is transmitted without distortion and fine control can be made, thereby exactly and precisely controlling a device. Also, there is an advantage of preventing a false operation of device by reducing noise level in signal transmission process. Also, in SMPS, even if large current is sensed, heat loss is minimized, thereby improving the efficiency of SMPS, and a resistor element or a magnetic element of rated dissipation is not used, thereby realizing the miniaturization of device and the cost reduction. Also, current can be exactly and precisely limited by reducing noise level and being transmitted without distortion.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that modifications in detail may be made without departing from the spirit and scope of the invention. | When a signal having a large shifted level is needed in a level shift circuit, a false operation is generated by the increase of noise level. And, when the signal level is very low, the circuit does not operate and generates distortion. The present circuit improves such problems. To do this, a capacitor or diode for coupling a signal generated from a signal source and level shifter for shifting the DC-coupled signal by a predetermined shift level is utilized. Accordingly, a variation of a small signal is transmitted without distortion to exactly and precisely control a device and noise level is reduced in a source signal transmission process, thereby preventing false operation of the device. | 7 |
This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 03075838.7, filed in Europe on Feb. 26, 2003, which is herein incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a printing method for a printer containing a transport system for a recording medium, and a printhead with a plurality of print units, each of which is capable of printing a pixel line when the printhead is scanned over the recording medium, wherein a failure compensation unit controls the print operation and compensates for a failure of a print unit.
An example of a printer of this type is disclosed in EP-A-0 981 105, which relates to an ink jet printer. In the printhead of this printer, the print units are formed by ink jet nozzles which are arranged in a linear array extending in the direction in which the recording medium is transported. Thus, when the printhead is scanned over the recording medium, a swath of an image can be printed, and the number of pixel lines in the swath corresponds essentially to the number of nozzles present in the printhead.
Such a printer can generally operate in different print modes. In a single-pass mode, each nozzle of the printhead prints the complete image information of a pixel line during a stroke in which the printhead is moved over the paper. Then, the paper is transported over the width of the swath that has been printed, and the next swath is printed in a return stroke of the printhead. As an alternative, a two-pass mode may be applied, in which each nozzle prints only every second pixel of the corresponding line during the first stroke, and the missing pixels are inserted in the return stroke of the printhead. In this mode, the paper may be transported in steps which correspond to only half the length of the nozzle array. Then, one half of the nozzles will be used for printing every second pixel of a new swath, whereas the other half of the nozzles is used for inserting the missing pixels in the swath that had been printed in the previous stroke. As a result, two different nozzles will be involved in printing all the pixels of a given pixel line.
If a nozzle of the printhead becomes clogged or fails for any other reason, the pixels that would have been printed with the inoperative nozzle will be missing in the printed image, and the image quality will be impaired. A variety of failure compensation strategies are known for avoiding or mitigating this undesirable effect.
For example, the above-mentioned document proposes a compensation strategy which employs the two-pass mode. Here, the job of the inoperative nozzle is taken over by the nozzle which is normally utilized only for inserting the missing pixels. Of course, if the scanning speed of the printhead is not reduced, this requires that the nozzle that is used for failure compensation is capable of printing pixels with twice the normal frequency.
EP-A-1 060 896 discloses a failure compensation strategy which is also applicable in a single-pass mode. When, in the event of breakdown of a nozzle, a specific pixel should but cannot be printed with the inoperative nozzle, this pixel is transferred to an addressable position in the vicinity of the designated pixel position, so that it can be printed with another nozzle. This strategy helps to prevent loss of information but will not fully compensate the nozzle failure and is in many cases sufficient for suppressing the visual effect of the nozzle failure below acceptable limits.
Another known failure compensation strategy is particularly applicable to the case where a breakdown of a nozzle or, more generally, a print unit occurs near the end of the nozzle array. Then, an end section of the nozzle array, which section includes the inoperative nozzle, is cut-off, i.e. the nozzles of this section are disabled. As a result, the usable length of the nozzle array is somewhat reduced, and the swath of the image that is printed in a single stroke is reduced in width. By adapting the transport width of the recording medium to the reduced width of the swath, a defect-free image can be printed, although at the cost of productivity.
In general, unless redundant nozzles are present in the printhead, failure compensation involves a tradeoff between productivity and image quality.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a printing method and a printer that are capable of optimizing the failure compensation strategy in terms of productivity and image quality for a large variety of images to be printed.
To this end, the printing method according to the present invention includes the steps of
storing a plurality of failure compensation strategies, dividing an image to be printed into segments containing different types of image information, and selecting different ones of the stored compensation strategies for printing different segments of the image.
As is generally known in the art, a segmentation process may be employed for analyzing the contents of an image to be printed and for identifying different types of image information such as text, CAD graphics, photographs and the like. In this way, it is possible for example to identify those parts of a page to be printed which contain photographs for which a halftone processing of the print data is necessary, whereas other parts of the page, e.g., text, do not need halftone processing. A segmentation process may also be used for automatically adapting the operation mode of the printer to the type of image information to be printed, so that different segments of a page may respectively be printed with the most suitable operation mode of the printer. For example, U.S. Pat. No. 6,149,264 discloses a printer in which a page to be printed is segmented into text areas and graphic areas, and a single-pass mode is adapted for text, whereas graphic data are printed in a two-pass mode.
According to the present invention, segmentation is employed for automatically switching between different failure compensation strategies, so that each segment of the image will be printed with a failure compensation strategy that is most suitable for the type of image information contained in the respective segment.
For example, the shift-type failure compensation strategy disclosed in EP-A-1 060 896, in which the black pixels that cannot be printed are shifted to neighboring locations, will be most suitable for relatively bright image areas, i.e. image areas in which the density of black pixels is comparatively low, so that a sufficient number of white pixel locations is available to which the black pixels may be shifted. In contrast, in a relatively dark image area, e.g. a solid black area, this compensation strategy is likely to lead to a visible defect in the printed image. In order to achieve a high image quality in such dark image areas, it would therefore be preferable to adopt one of the other failure compensation strategies discussed above which are capable of fully compensating the defect but which will generally lead to certain losses in productivity. It is a main advantage of the present invention that, when a page to be printed contains both, dark and bright image areas, it is not necessary to use a relatively slow failure compensation strategy, which assures a good image quality in the dark areas, for the whole page, but it is possible to use this slower strategy only where it is actually needed, whereas other parts of the page, i.e. the bright image areas, can be printed with a more productive failure compensation strategy which nevertheless provides a sufficient image quality in these areas. As a result, it is possible to achieve a satisfactory image quality and nevertheless to increase the overall productivity of the print operation.
Although it would be feasible to change the failure compensation strategy even within a single stroke of the printhead, it will generally be more efficient to retain one and the same compensation strategy for a complete printhead stroke. Thus, the segments identified in the segmentation process will preferably consist of swaths or bands that extend over the whole width of the page and correspond to an integral number of strokes of the printhead. Then, the part of the segment that is most sensitive to failure of a print unit will determine the compensation strategy to be adopted.
In a preferred embodiment, the printer comprises a failure detection system which automatically detects failures of print units, so that appropriate failure compensation strategies may be activated automatically. Failure detection and compensation may even be performed “on the fly”, i.e. while the printer is operating. Then, when a nozzle failure occurs at a time when the printer has printed a part of a page, the failure compensation unit will be activated immediately, so that the printer can continue with printing average number of black pixels contained in a given basic area. The minimum requirement for image quality and hence the failure compensation strategy to be applied may then be determined simply by setting threshold values to which the primary image classifiers are compared. In order to increase the sensitivity of the segmentation process, there may be provided a set of different primary image classifiers which differ from one another in the size of the basic area. Each classifier may then be compared to an associated threshold value, and the comparison results may be filtered with an appropriate filter in order to determine the ultimate compensation strategy.
It has been observed that a defect in the printed image, which defect may be the result of an incomplete failure compensation, is less perceptible to the human eye when there exists a high level of high-frequency contrast in the vicinity of the defect. In order to take advantage of this effect, it is preferable to employ a context filtering procedure in the segmentation process. The context filter may be applied to the primary classifiers or, alternatively, to the associated threshold values, e.g. by shifting the threshold values depending on the level of contrast in the basic area or the vicinity thereof.
The size of the segments determined in the segmentation process will naturally be adapted to the pattern of swaths printed by the printhead, i.e. the length of the nozzle array in the direction of paper transport. Since a frequent switching between different failure the rest of the page with failure compensation. Thus, visible defects in the printed image will only occur in the relatively short delay time between the detection of a nozzle failure and the time when the failure compensation unit becomes effective.
In some cases, however, even a short delay time between failure detection and failure compensation may lead to an unacceptable loss of image information. This is particularly the case when a thin horizontal line has to be printed, i.e. a line which extends in the scanning direction of the printhead and has a width of only a single pixel. Then, when the nozzle that is responsible for printing this pixel line becomes defective, the whole line will disappear. If, in that instant, the printer is in the single-pass mode, there will be no efficient way to compensate for this defect.
This problem may be solved according to the present invention by configuring or programming the segmentation unit to search for critical (nozzle failure sensitive) image items such as thin horizontal lines, so that an appropriate failure compensation strategy may be applied proactively or precautionarily. Of course, the ultimate failure compensation strategy can only be determined when the exact location is known where the nozzle failure has occurred, and this information will be available only a certain time after the failure has been detected. However, it is possible and advisable to proactively adopt a multi-pass print mode for such critical segments, so that the powerful failure compensation strategies that require a multi-pass mode are readily available. Then, when a nozzle failure is detected in the first pass of a two-pass mode, the defect may be compensated in the second pass. If the failure is detected only in the second pass, at least every second pixel in the defective line will have been printed already in the first pass, so that the visible effect of the failure is at least mitigated and complete loss of information is avoided.
According to another optional feature of the present invention, at least two and preferably more than two different failure compensation strategies are implemented in the printer, e.g. by storing appropriate compensation programs in the memory of the failure compensation unit, and these compensation strategies are ordered in a sequence with increasing image quality and decreasing productivity. Then, the segmentation process comprises a step of specifying for each segment a minimum requirement for image quality, depending on the image information contained in the segment, and the controller selects the first compensation strategy in the sequence that fulfils this minimum requirement.
As has been mentioned already, the darkness or brightness of an image area is an important criterion for selecting the failure compensation strategy. In the segmentation process, this criterion may be quantified by measuring a primary image classifier which is a measure for the darkness or the brightness of the image area. In the case of a bi-level print process in which a single pixel can only be printed either in black or in white, a suitable primary image classifier may, for example, be the compensation strategies and, especially, a frequent switching between single-pass and multi-pass, may itself lead to a loss in productivity, it is preferable to apply a low-pass filter to the segments in order to reduce the number of switch operations.
The present invention is not only applicable to black and white printers but also to color printers. In a color printer, the hybrid failure compensation process described above may be applied individually to each color separation image, preferably with different segmentation criteria for the different colors, because, for example, a defect in a yellow color separation will be less visible than one in cyan. In case of a color printer, it is also possible to employ additional inter-color failure compensation strategies. For example, in four color printing with the basic colors yellow, cyan, magenta and black with subtractive color composition, a failure of a black nozzle may be compensated by superimposing yellow, magenta and cyan pixels. Consequently, a failure of a cyan nozzle, for example, may be compensated to some extent by inserting black pixels so as to reproduce at least the grey level of the surroundings.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1 is a diagram showing essential parts of an ink jet printer to which the present invention is applicable;
FIGS. 2 to 5 show images of a page to be printed, for illustrating the effect of a segmentation process;
FIG. 6 is a block diagram of a failure compensation unit of the printer;
FIGS. 7–12 are diagrams for explaining different failure compensation strategies;
FIG. 13 is a diagram illustrating a step in the segmentation process; and
FIG. 14 is a flow chart of a process for selecting a failure compensation strategy in a print process.
DETAILED DESCRIPTION OF THE INVENTION
As is shown in FIG. 1 , an ink jet printer comprises a platen 10 driven for rotation in the direction of an arrow A for transporting a paper sheet 12 which serves as an image recording medium. A printhead 14 is mounted on a carriage 16 which is guided on guide rails 18 and travels back and forth in the direction of an arrow B along the platen 10 so as to scan the paper sheet 12 . The printhead 14 comprises four nozzle heads 20 , one for each of the basic colors yellow, cyan, magenta and black. On the side facing the sheet 12 , each nozzle head 20 has a linear array of nozzles 22 . The nozzle heads 20 are energized in accordance with image information of an image to be printed on the sheet 12 . Each nozzle 22 can be energized separately so as to eject an ink droplet which will form a dot at a corresponding pixel position on the sheet 12 . Thus, when the printhead 14 performs a single stroke along the platen 10 , each nozzle 22 can be energized to draw a single pixel line of the intended image. As a result, during each forward or backward stroke of the carriage 16 , the printhead 14 will print a swath or band of the image, and the number of pixel lines of the swath will correspond to the number of nozzles 22 present in each nozzle array. Although only eight nozzles 22 have been shown per nozzle head 20 in FIG. 1 , in practice, the number of nozzles will be considerably larger.
Each nozzle head 20 has an electronic failure detector 24 capable of detecting failure of a nozzle in the associated nozzle head. The failure detector will also indicate the location of the nozzle or nozzles that have become inoperative. As an alternative, a failure detector may be provided near one end of the platen 10 in a position outside of the area of the sheet 12 , and when the carriage has reached the position of this detector at the end of a stroke, the detector will check whether ink droplets have actually been expelled from each of the nozzles 22 .
When a failure of one or more of the nozzles 22 has been detected by the failure detectors 24 , one of a plurality of failure compensation strategies will be called-up in order to compensate for the breakdown of the nozzle or nozzles, as will be explained in detail below.
FIG. 2 shows an example of an image of a page 26 to be printed. In this simplified example, the image comprises a number of image items 28 , 30 , 32 and 34 which include different types of image information. In the example shown, item 28 is a relatively dark narrow horizontal bar, item 30 is a photograph with comparatively large dimensions and a comparatively high average darkness, item 32 is a thin horizontal line which has only a width of a single pixel, and item 34 is a text item.
The photograph 30 is relatively sensitive to nozzle failure, because a missing pixel line would be clearly visible on the dark background. The thin horizontal line 32 is also very sensitive to nozzle failure, because a failure of the pertinent nozzle would lead to a complete loss of image information. In contrast, the items 28 and 34 are less sensitive to nozzle failure, because a missing pixel line would always be located in the vicinity of a borderline where there exists a sharp contrast between dark and bright which would somewhat shield the image defect so that the latter is less perceptible. Under these circumstances, items 30 and 32 would require a failure compensation strategy which results in a high image quality and avoids a complete loss of image information, respectively. Such compensation strategies will generally require a slower operation mode of the printhead, so that the time required for printing the page 26 would be increased. On the other hand, the items 28 and 34 would permit a failure compensation strategy which only mitigates the effect of the nozzle failure rather than completely compensating for the same, and such failure compensation strategies permit a higher printing speed.
In order to be able to adopt an optimal failure compensation strategy in terms of image quality and productivity for each of the items 28 – 34 , a segmentation process is applied to the image in order to identify the different image items and to evaluate the type of image information contained therein. In FIG. 2 , two preliminary segments 36 and 38 corresponding to the items 30 and 32 are indicated in dot-dashed lines. Since a failure compensation strategy will always apply to one or more complete strokes of the printhead 14 , the segments 36 and 38 each extend over the whole width of the page 26 . For simplicity, it is assumed here that the rest of the page 26 , i.e. the areas outside of the segments 36 and 38 form segments that can be printed with a simple, relatively fast failure compensation strategy.
FIG. 3 shows the page 26 divided into a number of swaths 40 which are each printed in a single stroke of the printhead 14 . It is assumed here that the printer operates in a single-pass mode, so that the swaths 40 do not or seldom overlap, and the sheet 12 will be transported by the width of a single swath after each stroke of the printhead.
In FIG. 4 , the size of the segments 36 , 38 has been matched to the raster of swaths 40 . It can be seen that the segments 36 and 38 are separated only by a single swath. As an example, it shall be assumed that the failure compensation strategy adopted for the segments 36 and 38 requires a two-pass mode, in which there is an overlap of 50% between the swaths covered by the printhead in the forward stroke and the rearward stroke. This has been symbolized by dot-lines 42 above and below the segment 38 . When the print mode is switched from single-pass to two-pass or vice versa, one half of a swath must be wasted. It would therefore not be efficient to switch over to the single-pass mode for the one swath existing between the segments 38 and 36 . For this reason, the pattern of segments is subjected to a low-pass filtering in order to avoid a too frequent and inefficient switching between the print modes. The result is shown in FIG. 5 where the segments 36 and 38 have been united to a single segment 44 .
FIG. 6 is a block diagram of a failure compensation unit 46 for the printer. The failure compensation unit may be configured as a physical unit comprising one or more processors, memories and the like or may be implemented in the general control software of the printer. The image data to be printed are input as a pixel bit stream 48 and are buffered in a print data file 50 . A memory 52 includes a number ( 5 in the given example) of failure compensation strategies, e.g. in the form of program code. The failure compensation strategies will be described below.
A segmentation unit 54 receives detection signals from the failure detectors 24 and has access to the data file 50 so as to perform the segmentation process described above with reference to FIGS. 2 to 5 . The result is a strategy file 56 which assigns one of the failure compensation strategies stored in the memory 52 to each of the (single-pass) swaths 40 . The swaths are counted from the bottom of the page 26 in FIG. 5 . In the example shown, swaths No. 6 to 11 form the segment 44 for which the compensation strategy No. 5 is applied, whereas strategy No. 1 is applied to the rest of the page.
A controller 58 reads the strategy file 56 and calls-up the failure compensation strategies from the memory 52 as determined by the strategy file. The controller also reads the image data file 50 , modifies the image data in accordance with the pertinent failure compensation strategy and outputs the modified image data 60 to the nozzle heads 20 and generates control data 62 to be output to other components of the printer such as carriage drive, paper transport and the like, so that the image will be printed in accordance with the failure compensation strategies as scheduled in the strategy file.
The various failure compensation strategies stored in the memory 52 will now be explained in conjunction with FIGS. 7 to 13 .
Strategy No. 1 , which is called “single-pass and shift” is illustrated in FIG. 7 . By way of example, it is assumed that the image of the pertinent segment consists of two slanting lines having each a width of two pixels and separated by a gap of three white pixels. The printer operates in the single-pass mode, so that all the information of a given pixel line has to be printed with only one nozzle of the nozzle head 20 for the respective color. It is assumed that a nozzle failure has occurred in pixel line 64 . Consequently, the pixels in line 64 and columns 66 , 68 , 70 and 72 should but cannot be printed with the pertinent nozzle, and a defect in the form of a white pixel line occurs in the printed image. In order to mitigate the visual impression of this defect, the pixels in columns 66 – 72 are shifted either upwards into the line above line 64 or downward into the line below line 64 . In column 66 , the pixel cannot be shifted upwards because the pixel thereabove would be black anyway. This is why this pixel is shifted downward to the location 74 . In contrast, the pixel in column 68 is shifted from line 64 into the line immediately thereabove. The same holds true for the pixels in columns 72 and 70 , respectively. Thus, the average darkness of the image is conserved even in the vicinity of the line 64 . Keeping in mind that the pixel size is largely exaggerated in FIG. 7 and will in practice be close to the limit of spatial resolution of the human eye, the resulting visual impression is fully acceptable. This failure compensation strategy also conserves the full productivity of the printer, because the operating speed of the printhead need not be reduced. However, this strategy would be less effective if the segment to be printed would consist of a solid black area.
Failure compensation strategy No. 2 “single-pass and cut” is slightly less productive but permits a complete failure compensation. This strategy, which is illustrated in FIG. 8 , is applicable when a nozzle failure occurs in a top or bottom end portion of the nozzle array of a nozzle head 20 . In FIG. 8 , the nozzle head 20 is symbolized by a rectangle, and an end portion 76 containing the inoperative nozzle has been hatched. The compensation strategy consists of cutting away, i.e. disabling the nozzles in the end portion 76 , so that the swath 40 ′ that is actually printed has a slightly reduced width. The paper transport distance at the end of a printhead stroke is reduced accordingly, so that the swaths 40 are seamlessly butted together, as can be seen in FIG. 8 .
FIG. 9 illustrates a modification of this strategy, which is even less productive but permits compensation for a nozzle failure in a central portion 78 of the nozzle head 20 . In this case, the central portion 78 having a length of one third of the complete nozzle array is disabled, so that the swath printed in a single stroke consists of two separate sub-swaths 40 a , 40 b . The gap between these swaths is inserted in the return stroke by the swath 40 a , i.e. the swaths 40 a and 40 b are interleaved. In the example shown in FIG. 6 , this strategy has not been implemented.
Failure compensation strategy No. 3 “two pass fast and shift” will now be explained in conjunction with FIGS. 10 and 11 . This strategy employs the shift mechanism that has already been described in conjunction with FIG. 7 , but now in a fast two-pass mode. A two-pass mode or, more generally, a multi-pass mode has the advantage that two or more nozzles are involved in printing a single pixel line, so that a nozzle failure will affect only some of the pixels in the line. This is illustrated in FIG. 10 , where, in lines 1 – 8 , all pixels having an odd column number have been printed in a forward pass n. In lines 1 – 4 , even-numbered pixels had been already printed in a previous return pass n− 1 . Due to a breakdown of a nozzle 22 ′, pixels are missing in lines 3 , 7 and 3 ′. However, as can be seen in line 7 , every second pixel can still be printed with an operative nozzle 22 ″. The black pixels in line 3 have been printed in the same way. Thus, switching to a two-pass mode has the effect that, even in case of a nozzle failure, the corresponding pixel line will not be missing completely but is still printed with an optical density of 50%.
By adopting the shift mechanism discussed above, the result can be improved further, as has been shown in FIG. 11 . This figure shows the same image as FIG. 7 , but now only the pixels in columns 68 and 70 need to be shifted, and the optical impression is improved significantly.
In the fast two-pass mode, the carriage 16 travelling along the platen 10 is driven with twice the normal speed, while the dot generation frequency of the nozzles 22 is kept at the original value. Thus, although two passes are needed for printing a complete swath, the productivity is almost as high as in the single-pass mode. However, a certain loss in productivity is caused by the necessity to decelerate the carriage 16 and to reverse its direction of movement more frequently. This is why strategy No. 3 is less productive than strategy No. 1 and even less productive than strategy No. 2 , if the cut-away portion 76 of the nozzle array is relatively short. On the other hand, a multipass mode leads to an improvement in the overall image quality because defects resulting from dot position errors, for example, can be made smooth.
The failure compensation strategy No. 4 shown in FIG. 6 , “two-pass fast and cut” employs the fast two-pass mode in combination with the cut procedure illustrated in FIG. 8 .
The failure compensation strategy No. 5 “single pass slow and insert” is illustrated in FIG. 12 . Here, the two-pass mode is adopted, but the carriage is moved only with normal speed, and the dot generation frequency of most of the nozzles 22 is reduced to 50%. As a consequence, the productivity of the print process is also reduced to 50%. On the other hand, this strategy has the advantage that a complete failure compensation can be achieved even in cases where nozzle failure occurs in a central portion of the nozzle array, so that the cut strategy of FIG. 8 would not work, or in cases where nozzle failure occurs for two adjacent nozzles, so that the shift strategy would not work. To compensate for the failure of nozzle 22 ′ in FIG. 12 , the complementary nozzle 22 ″ is operated with the normal drop generation frequency, i.e. twice the frequency of the other nozzles, so that all the pixels missing in line 7 can be filled-in with the nozzle 22 ″.
In a modified embodiment, it is possible that the printer operates with a nominal dot generation frequency of 10 kHz, for example, but is also capable of operating with twice the nominal dot generation frequency, i.e. 20 kHz. The mode with nominal frequency will then be used, for example, in a quality mode in order to achieve an optimal image quality, whereas the mode with double frequency, in which the image quality may be slightly less, will be adopted in a draft mode, for example. Then, in the quality mode, the strategy shown in FIG. 12 may be applied with the nominal dot generation frequency and double carriage speed, and only the nozzle 22 ″ will be operated with double frequency, so that a higher productivity can be achieved.
Of course, other failure compensation strategies that are known in the art may also be implemented, and the set of selectable compensation strategies may be varied depending upon the operating mode (draft, normal or quality) of the printer.
Details of the segmentation process employed in the segmentation unit 54 will now be explained with reference to FIG. 13 . This figure shows a pixel pattern of a portion of an image to be printed, as specified in the data file 50 . In the example shown, most of the area has a grey level of 50%, i.e. one half of the pixels is black and the other half is white. The image area is divided into square basic areas of, preferably, 32×32 pixels, although only 8×8 pixels have been shown in the drawing. One basic area 80 has been highlighted in FIG. 13 by a white borderline.
A first step in the segmentation process consists of measuring the average brightness of each basic area by counting the number of white pixels. This average brightness will be taken as a primary image classifier for determining the failure compensation strategy to be applied. The value 0 is assigned to black pixels, and the value 255 is assigned to white pixels. Thus, the average image value of the basic area 80 will be 127. In general, a high value of the primary image classifier means that a rather productive failure compensation strategy, e.g. strategy No. 1 , can be applied, whereas a low primary image classifier means that one of the high quality strategies, e.g. strategy No. 5 , has to be applied.
In the next step, the primary image classifiers are subjected to context filtering in view of the fact that a defect caused by a nozzle failure will be less visible when it occurs near a border between the dark area and an adjacent bright area. To this end, a square window of 5×5 basic areas is shifted over the image, with the basic area 80 that is currently inspected being in the center of this window. In FIG. 13 , the 5×5 window surrounding the basic area 80 is indicated as the base of a pyramid 82 . The primary image classifiers measured for each of the 25 basic areas in the window 82 are subjected to maximum filtering. Since, in the example shown, all 25 basic areas have the primary image value of 127, the maximum is also 127, as is indicated on the top of the pyramid symbolizing the window 82 . However, when the window is shifted by one basic area to the right, in order to inspect a basic area 84 , the window, which is now symbolized by a pyramid 86 shown in dashed lines, includes also a brighter basic area 88 which has a basic image classifier of 191. Then, maximum filtering leads to a filtered image value of 191 for the basic area 84 . In this way, by shifting the window over the whole page 26 , a filtered primary classifier is obtained for each basic area.
In a simplified version of the segmentation process, the next step consists of comparing the filtered primary classifiers to appropriate threshold values. When the filtered primary classifiers of all basic areas in a row extending over the whole width of the page 26 exceed the highest threshold value, then this row of basic areas can be classified as part of a segment to which the failure compensation strategy No. 1 applies. On the other hand, if none of the filtered primary classifiers in this row exceeds the lowest threshold value, then this row will be classified as part of a segment to which failure compensation strategy No. 5 applies. In this way, the provisional segment 36 shown in FIG. 2 can be obtained, whereas the items 28 , 32 and 34 have passed the context filtering procedure for strategy No. 1 . The segment 38 corresponding to the single pixel line 32 is obtained by a different process, as will be explained below.
FIG. 14 is a flow chart illustrating a more elaborated segmentation process.
In step 100 , the data file 50 is read-in. In step 101 , the whole image of the page 26 is checked for thin horizontal lines such as the line 32 in FIG. 2 . This is achieved by conventional image processing techniques that are known in the art. If one or more of such horizontal lines are found, a proactive failure compensation strategy is scheduled in step 102 . This step includes the identification of the segment 38 , as in FIG. 2 , and the matching of the segment to the swath width, as in FIG. 4 . In the example shown, the steps 100 – 102 are performed before the operation of the printhead 14 starts. It is further specified in step 102 that the failure compensation strategy No. 5 shall be adopted for the segment 38 , even though it is not known at that instant whether a nozzle failure will actually occur and which nozzle will be affected. In any case, a two-pass mode will be scheduled for this segment. This has the advantage that the failure compensation process can readily be activated if the demand occurs. Thus, a complete loss of information can reliably be avoided.
In a modified embodiment, it would also be possible to schedule the failure compensation process No. 3 for horizontal lines having a width of two pixels, for example.
It should further be observed here that it would also be possible to employ the failure compensation strategy No. 1 (shift) for single-pixel lines. Then, the line as a whole would be shifted by one pixel. However, in the case of high quality printing of CAD graphics, where positional accuracy is important, this strategy may not be acceptable.
Subsequent to step 102 , the printhead 14 is started to operate in step 104 . If no thin horizontal lines have been found in step 101 , then the step 102 is skipped.
In step 105 , it is checked by means of the failure detectors 24 whether or not a nozzle failure has occurred, and the location of the nozzle failure or failures is communicated to the segmentation unit 54 . If no nozzle failure has been detected, the step 105 is repeated in a loop while the page is being printed.
As soon as a nozzle failure occurs, threshold values Tij for the segmentation process are set in step 106 . The index i (i=1, . . . , 5) identifies the failure compensation strategy to which the threshold value applies. It will be noted that, as is shown in FIG. 6 , the compensation strategies are ordered in a sequence with increasing image quality and decreasing productivity. Thus, i=1 means highest productivity and i=5 means highest quality.
In the segmentation process of this embodiment, primary image classifiers Bj are measured for basic areas (such as 80) with different sizes, e.g. with sizes of 8†×†8, 16×16, 32×32 pixels and so on (and possibly also for different window sizes such as 5×5 or 3×3 basic areas). The second index j of the classifiers Bj and of the threshold values Tij identifies the type or size of basic area to which the classifiers and threshold values apply.
In step 107 , the primary classifiers Bj are measured for the various sizes of the basic areas, of course always for rows of basic areas extending over the whole width of the page 26 .
In step 108 , context filtering is applied individually to each set of primary classifiers Bj.
In step 109 , the index i is set to 1. In step 110 , it is checked whether all the filtered primary classifiers Bj for all sizes of the basic areas and for all basic areas in the row are larger than the maximum max j (Tij) of the threshold values Tij. Since, in the present instant, i has been set to 1, the maximum is taken over the threshold values Tij. If the condition checked in step 110 is fulfilled, the failure compensation strategy i ( 1 ) is adopted in step 111 . Since the values Bj have been compared to the maximum of the threshold values Tij in step 110 , the failure compensation strategy No. 1 with the highest productivity will be applied only if the values Bj for all sizes of the basic areas have passed the test in step 110 .
If the test in step 110 has failed, it is checked in step 111 whether the index i has reached the maximum value 5 . If this is not the case, i is incremented in step 113 , and the process loops back to step 110 . Thus, the loop consisting of the steps 110 , 111 , 112 and 113 identifies the failure compensation strategy with the highest productivity which still provides a sufficient image quality for the segment that is being inspected. If none of the strategies No. 1 – 4 has passed the test in step 110 , the loop is exited with step 114 where the strategy No. 5 for highest quality is scheduled.
Subsequent to step 111 or step 114 , the process loops back to step 105 , where it is checked whether a new nozzle failure has occurred while the print process proceeds. It will be understood that the steps 105 through 114 are repeated until the whole page 26 or at least a certain number of adjacent swaths 40 has been examined with basic areas of all sizes, thereby determining the dimensions of the segments 36 , 38 as in FIG. 4 . Finally, although this is not shown in FIG. 14 , the segments are subjected to low-pass filtering in order to remove unreasonably small gaps between segments of the same type, as has been shown in FIG. 5 .
The threshold values Tij determined in step 106 may of course depend upon the locations of the defective nozzles as detected in step 105 . Thus, step 106 should be performed after step 105 . However, the steps 107 and 108 may be performed prior to step 106 or to step 105 or even before the print process has started in step 104 . This will reduce the processing time needed after a nozzle failure has been detected and will therefore permit a quicker reaction time when a nozzle failure occurs.
On the other hand, the nozzle failures detected in step 105 may be stored in a nonvolatile memory, so that they are readily available when the printer has been switched off and is switched on again at a later time.
Due to the powerful and yet productive failure compensation mechanism according to the present invention, it is possible to extend the cleaning or maintenance intervals for the printer and/or to reduce the number of instances where service personal has to be called for mending nozzle failures.
With increasing resolution of printers, and hence with increasing numbers of nozzles or other print units and decreasing dimensions of the print units, the likelihood of nozzle failures becomes larger, not only when the printer is in use but already in the production process of the printhead. The present invention may also tolerate a certain number of nozzle failures for a virgin printhead, thereby increasing the yield in the manufacturing process of the printhead.
The invention being 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 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. | A printer including a transport system for a recording medium, a printhead containing a plurality of print units each of which being capable of printing a pixel line when the printhead is scanned over the recording medium, and a failure compensation unit for controlling the print operation such that a failure of a print unit is compensated, wherein a segmentation unit is provided for dividing an image to be printed into segments containing different types of image information, and wherein the failure compensation unit includes a memory for storing a plurality of compensation strategies and a controller for selecting one of said compensation strategies in accordance with the segment to be printed. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is continuation application of U.S. application Ser. No. 12/801,952, filed Jul. 2, 2010, now U.S. Pat. No. 7,942,026 which was a continuation of U.S. application Ser. No. 12/659,980, filed Mar. 26, 2010, which issued as U.S. Pat. No. 7,797,970, which was a divisional of U.S. application Ser. No. 11/806,245, filed May 30, 2007, which issued as U.S. Pat. No. 7,743,633, which in turn claims the benefit of Korean Patent Application Nos. 2006-49501 and 2006-49482, both filed on Jun. 1, 2006, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference.
BACKGROUND
1. Field
The present invention relates generally to a washing machine having at least one balancer, and more particularly to a washing machine having at least one balancer that increases durability by reinforcing strength and that is installed on a rotating tub in a convenient way.
2. Description of the Related Art
In general, washing machines do the laundry by spinning a spin tub containing the laundry by driving the spin tub with a driving motor. In a washing process, the spin tub is spun forward and backward at a low speed. In a dehydrating process, the spin tub is spun in one direction at a high speed.
When the spin tub is spun at a high speed in the dehydrating process, if the laundry leans to one side without uniform distribution in the spin tub or if the laundry leans to one side by an abrupt acceleration of the spin tub in the early stage of the dehydrating process, the spin tub undergoes a misalignment between the center of gravity and the center of rotation, which thus causes noise and vibration. The repetition of this phenomenon causes parts, such as a spin tub and its rotating shaft, a driving motor, etc., to break or to undergo a reduced life span.
Particularly, a drum type washing machine has a structure in which the spin tub containing laundry is horizontally disposed, and when the spin tub is spun at a high speed when the laundry is collected on the bottom of the spin tub by gravity in the dehydrating process, the spin tub undergoes a misalignment between the center of gravity and the center of rotation, thus resulting in a high possibility of causing excess noise and vibration.
Thus, the drum type washing machine is typically provided with at least one balancer for maintaining a dynamic balance of the spin tub. A balancer may also be applied to an upright type washing machine in which the spin tub is vertically installed.
An example of a washing machine having ball balancers is disclosed in Korean Patent Publication No. 1999-0038279. The ball balancers of a conventional washing machine include racers installed on the top and the bottom of a spin tub in order to maintain a dynamic balance when the spin tub is spun at a high speed, and steel balls and viscous oil are disposed within the racers to freely move in the racers.
Thus, when the spin tub is spun without maintaining a dynamic balance due to an unbalanced eccentric structure of the spin tub itself and lopsided distribution of the laundry in the spin tub, the steel balls compensate for this imbalance, and thus the spin tub can maintain the dynamic balance.
However, the ball balancers of the conventional washing machine have a structure in which upper and lower plates formed of plastic by injection molding are fused to each other, and a plurality of steel balls are disposed between the fused plates to make a circular motion, so that the ball balancers are continuously supplied with centrifugal force that is generated when the steel balls make a circular motion, and thus are deformed at walls thereof, which reduces the life span of the balancer.
Further, the ball balancers of the conventional washing machine do not have a means for guiding the ball balancers to be installed on the spin tub in place, so that it takes time to assemble the balancers to the spin tub.
In addition, the ball balancers of the conventional washing machine have a structure in which a racer includes upper and lower plates fused to each other, so that fusion scraps generated during fusion fall down both inwardly and outwardly of the racer. The fusion scraps that fall down inwardly of the racer prevent motion of the balls in the racer, and simultaneously result in generating vibration and noise.
SUMMARY
Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a washing machine having at least one balancer that increases durability by reinforcing the strength of the balancer, which is installed on a rotating tub in a rapid and convenient way.
Another object of the present invention is to provide a washing machine having at least one balancer, in which fusion scraps generated by fusion of the balancer are prevented from falling down inward and outward of the balancer.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.
In order to accomplish these objects, according to an aspect of the present invention, there is provided a washing machine having a spin tub to hold laundry to be washed and at least one balancer. The balancer includes first and second housings, the first housing having at least one support for reinforcing a strength of the balancer. The first and second housings have an annular shape and are fused together to form a closed internal space.
Here, the first housing may have the cross section of an approximately “C” shape, and the support protrudes outwardly from at least one of opposite walls of the first housing.
Further, the spin tub may include at least one annular recess corresponding to the balancer such that the balancer is able to be coupled to the spin tub by being fitted within the recess.
Further, the support may protrude from the first housing and comes into contact with a wall of the recess, and guides the balancer to be maintained in the recess in place.
Also, the supports may be continuously formed along and perpendicular to the opposite walls of the first housing.
Further, the supports may be disposed parallel to the opposite walls of the first housing at regular intervals.
Meanwhile, the washing machine may be a drum type washing machine. A front member may be attached to a front end of the spin tub and a rear member may be attached to a rear end of the spin tub. The recesses may be provided at the front and rear members of the spin tub, and the balancers may be coupled to opposite ends of the spin tub at the recesses of the front and rear members.
The foregoing and/or other aspects of the present invention can be achieved by providing a washing machine having at least one balancer. The balancer includes a first housing and a second housing fused to the first housing, and the first and second housings are fused together to form at least one pocket between the first housing and the second housing, the pocket capable of collecting fusion scraps generated during fusion.
Here, the first housing may include protruding fusion ridges protruding from ends of the first housing, and the second housing may include fusion grooves receiving the fusion ridges of the first housing when the first housing and the second housing are fused together.
Further, the first housing may further include inner pocket ridges protruding from the first housing and spaced inwardly apart with respect to the fusion ridges of the first housing.
Further, the second housing may further include outer pocket flanges protruding from the second housing and being situated on outer sides of the fusion grooves when the first housing is fused together with the second housing so the outer pocket flanges are spaced apart from the fusion ridges of the first housing by a predetermined distance, causing an outer pocket to be formed between the fusion ridges and the outer pocket flanges.
Further, the second housing may include guide ridges protruding from the second housing and protruding toward the first housing to closely contact the inner pocket ridges of the first housing when the first and second housings are fused together.
Also, the balancer may further include a plurality of balls disposed within an internal space formed by fusing the first and second housings together, the balls performing a balancing function.
In addition, the washing machine may further include a spin tub disposed horizontally, and the balancers may be installed at front and rear ends of the spin tub.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which
FIG. 1 is a sectional view illustrating a schematic structure of a washing machine according to the present invention;
FIG. 2 is a perspective view illustrating balancers according to the present invention, in which the balancers are disassembled from a spin tub;
FIG. 3 is a perspective view illustrating a balancer according to a first embodiment of the present invention;
FIG. 4 is an enlarged view illustrating section A of FIG. 1 in order to show the sectional structure of a balancer according to a first embodiment of the present invention;
FIG. 5 is a perspective view illustrating a balancer according to a second embodiment of the present invention;
FIG. 6 is an enlarged view illustrating the sectional structure of a balancer according to the second embodiment of the present invention;
FIG. 7 is a perspective view illustrating a disassembled balancer according to a third embodiment of the present invention;
FIG. 8 is a perspective view illustrating an assembled balancer according to the third embodiment of the present invention;
FIG. 9 is a partially enlarged view of FIG. 7 ; and
FIG. 10 is a sectional view taken line A-A of FIG. 8 .
DETAILED DESCRIPTION OF THE EMBODIMENTS
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.
Hereinafter, exemplary embodiments of the present invention will be described with reference to the attached drawings.
FIG. 1 is a sectional view illustrating the schematic structure of a washing machine according to the present invention.
As illustrated in FIG. 1 , a washing machine according to the present invention includes a housing 1 forming an external structure of the washing machine, a water reservoir 2 installed in the housing 1 and containing washing water, a spin tub 10 disposed rotatably in the water reservoir 2 which allows laundry to be placed in and washed therein, and a door 4 hinged to an open front of the housing 1 .
The water reservoir 2 has a feed pipe 5 and a detergent feeder 6 both disposed above the water reservoir 2 in order to supply washing water and detergent to the water reservoir 2 , and a drain pipe 7 installed therebelow in order to drain the washing water contained in the water reservoir 2 to the outside of the housing 1 when the laundry is completely done.
The spin tub 10 has a rotating shaft 8 disposed at the rear thereof so as to extend through the rear of the water reservoir 2 , and a driving motor 9 , with which the rotating shaft 8 is coupled, installed on a rear outer side thereof. Therefore, when the driving motor 9 is driven, the rotating shaft 8 is rotated together with the spin tub 10 .
The spin tub 10 is provided with a plurality of dehydrating holes 10 a at a periphery thereof so as to allow the water contained in the water reservoir 2 to flow into the spin tub 10 together with the detergent to wash the laundry in a washing cycle, and to allow the water to be drained to the outside of the housing 1 through a drain pipe 7 in a dehydrating cycle.
The spin tub 10 has a plurality of lifters 10 b disposed longitudinally therein. Thereby, as the spin tub 10 rotates at a low speed in the washing cycle, the laundry submerged in the water is raised up from the bottom of the spin tub 10 and then is lowered to the bottom of the spin tub 10 , so that the laundry can be effectively washed.
Thus, in the washing cycle, the rotating shaft 8 alternately rotates forward and backward by of the driving of the driving motor 9 to spin the spin tub 10 at a low speed, so that the laundry is washed. In the dehydrating cycle, the rotating shaft 8 rotates in one direction to spin the spin tub 10 at a high speed, so that the laundry is dehydrated.
When spun at a high speed in the dehydrating process, the spin tub 10 itself may undergo misalignment between the center of gravity and the center of rotation, or the laundry may lean to one side without uniform distribution in the spin tub 10 . In this case, the spin tub 10 does not maintain a dynamic balance.
In order to prevent this dynamic imbalance to allow the spin tub 10 to be spun at a high speed with the center of gravity and the center of rotation thereof matched with each other, the spin tub 10 is provided with balancers 20 or 30 according to a first or a second embodiment of the present invention (wherein only the balancer 20 according to a first embodiment is shown in FIGS. 1-4 ) at front and rear ends thereof. The structure of the balancers 20 and 30 according to the first and second embodiments of the present invention will be described with reference to FIGS. 2 through 6 .
FIG. 2 is a perspective view illustrating balancers according to the present invention, in which the balancers are disassembled from a spin tub.
As illustrated in FIG. 2 , the spin tub 10 includes a cylindrical body 11 that has open front and rear parts and is provided with the dehydrating holes 10 a and lifters 10 b , a front member 12 that is coupled to the open front part of the body 11 and is provided with an opening 14 permitting the laundry to be placed within or removed from the body 11 , and a rear member 13 that is coupled to the open rear part of the body 11 and with the rotating shaft 8 (see FIG. 1 ) for spinning the spin tub 10 .
The front member 12 is provided, at an edge thereof, with an annular recess 15 that has the cross section of an approximately “C” shape and is open to the front of the front member 12 in order to hold any one of the balancers 20 . Similarly, the rear member 13 is provided, at an edge thereof, with an annular recess 15 (not shown) that is open to the rear of the front member 12 in order to hold the other of the balancers 20 .
The front and rear members 12 and 13 are fitted into and coupled to the front or rear edges of the body 11 in a screwed fashion or in any other fashion that allows the front and rear members 12 and 13 to be maintained to the body 11 of the spin tub 10 .
The balancers 20 , which are installed in the recesses 15 of the front and rear members 12 and 13 , have an annular shape and are filled therein with a plurality of metal balls 21 performing a balancing function and a viscous fluid (not shown) capable of adjusting a speed of motion of the balls 21 .
Now, the structure of the balancers 20 and 30 according to the first and second embodiments of the present invention will be described with reference to FIGS. 3 through 6 .
FIG. 3 is a perspective view illustrating a balancer according to a first embodiment of the present invention, and FIG. 4 is an enlarged view illustrating part A of FIG. 1 in order to show the sectional structure of a balancer according to a first embodiment of the present invention.
As illustrated in FIGS. 3 and 4 , a balancer 20 according to a first embodiment of the present invention has an annular shape and includes first and second housings 22 and 23 that are fused to define a closed internal space 20 a.
The first housing 22 has first and second walls 22 a and 22 b facing each other, and a third wall 22 c connecting ends of the first and second walls 22 a and 22 b , and thus has a cross section of an approximately “C” shape. The second housing 23 has opposite edges that protrude toward the first housing 22 and that are coupled to corresponding opposite ends 22 d of the first housing 22 by heat fusion.
The opposite ends 22 d of the first housing 22 protrude outward from the first and second walls 22 a and 22 b of the first housing 22 , and the edges of the second housing 23 are sized to cover the ends 22 d of the first housing 22 .
Thus, when the balancer 20 is fitted into the recess 15 of the front member 12 of the spin tub 10 , the first and second walls 22 a and 22 b are spaced apart from a wall of the recess 15 because of the ends and edges of the first and second housings 22 and 23 which protrude outward from the first and second walls 22 a and 22 b . Further, because the first and second walls 22 a and 22 b are relatively thin, the first and second walls 22 a and 22 b are raised outward when centrifugal force is applied thereto by the plurality of balls 21 that move in the internal space 20 a of the balancer 20 in order to perform the balancing function.
In this manner, the plurality of balls 21 make a circular motion in the balancer 20 , so that the first and second walls 22 a and 22 b are deformed by the centrifugal force applied to the first and second walls 22 a and 22 b of the first housing 22 . In order to prevent this deformation, the second housing 22 is provided with supports 24 according to a first embodiment of the present invention.
The supports 24 protrude from and perpendicular to the first and second walls 22 a and 22 b of the first housing 22 which are opposite each other, and may be continued along an outer surface of the first housing 22 , thereby having an overall annular shape.
The supports 24 have a length such that they extend from the first housing 22 to contact the wall of the recess 15 . Hence, the first and second walls 22 a and 22 b are further increased in strength, and additionally function to guide the balancer 20 so as to be maintained in the recess 15 in place.
Here, when the plurality of balls 21 make a circular motion in the first housing 22 , the centrifugal force acts in the direction moving away from the center of rotation of the spin tub 10 . Hence, the centrifugal force acts on the first wall 22 a to a stronger level when viewed in FIG. 4 . Thus, the supports 24 may be formed only on the first wall 22 a.
In the balancer 20 according to the first embodiment of the present invention, when the first and second housings 22 and 23 are fused together and fitted into the recess 15 of the spin tub 10 , the supports 24 are maintained in place while positioned along the wall of the recess 15 . Finally, the balancer 20 is coupled and fixed to the front member 12 of the spin tub 10 by screws (not shown) or in any other fashion that allows the balancer 20 to be coupled to the front member 12 .
Although not illustrated in detail, the balancer 20 is similarly installed on the rear member 13 of the spin tub 10 .
The ends 22 d of the first housing 22 include fusion ridges 42 a that protrude toward the second housing 23 . The fusion ridges 42 a are inserted within fusion grooves 43 a of the second housing 23 .
FIGS. 5 and 6 correspond to FIGS. 3 and 4 , and illustrate a balancer 30 according to a second embodiment of the present invention.
The balancer 30 according to the second embodiment of the present invention has an annular shape and includes first and second housings 32 and 33 that are fused together forming an internal space 30 a therebetween in which a plurality of balls 31 are disposed. The balancer 30 according to the second embodiment of the present invention is similar to that of balancer 20 according to the first embodiment of the present invention, except the structure of supports 34 of balancer 30 is different from that of the structure of the supports 24 of balancer 20 .
As illustrated in FIGS. 5 and 6 , the supports 34 according to the second embodiment of the present invention protrude parallel to first and second walls 32 a and 32 b of a first housing 32 which are opposite each other, and the supports 34 are disposed at regular intervals along the first and second walls 32 a and 32 b . The first housing 32 further includes a third wall 32 c . Ends 22 d of the first housing 32 extend from an end of the first and second walls 32 a and 32 b.
Similar to the supports 24 according to the first embodiment, the supports 34 of the second embodiment have a length such that the supports 34 extend from the first housing 32 to contact the wall of the recess 15 . The surfaces of the supports 34 thereby abut portions of the front member 12 . Hence, the first and second walls 32 a and 32 b are further increased in strength, and additionally function to guide the balancer 30 so as to be maintained in the recess 15 in place.
Next, the construction of a balancer 40 according to a third embodiment of the present invention will be described with reference to FIGS. 7 through 10 .
FIGS. 7 and 8 are perspective views illustrating disassembled and assembled balancers according to the third embodiment of the present invention, FIG. 9 is a partially enlarged view of FIG. 7 , and FIG. 10 is a sectional view taken along line A-A of FIG. 8 .
As illustrated in FIGS. 7 and 8 , a balancer 40 includes a first housing 42 having an annular shape and a second housing 43 having an annular shape that is fused to the first housing 42 , thereby forming an annular housing corresponding to the recess 15 (see FIG. 2 ) of the spin tub 10 . The first and second housings 42 and 43 may be, for example, formed of synthetic resin, such as plastic by injection molding.
As illustrated in FIG. 9 , the first housing 42 has a cross section of an approximately “C” shape, includes fusion ridges 42 a protruding to the second housing 43 at opposite ends thereof which are coupled with the second housing 43 , and inner pocket ridges 42 b protruding to the second housing 43 spaced inwardly apart from the fusion ridges 42 a.
The second housing 43 has a first surface 431 facing the first housing 42 and a second surface 432 opposite to the first surface 431 . The second housing 43 , which is coupled to opposite ends of the first housing 42 in order to form a closed internal space 40 a for holding a plurality of balls 41 and a viscous fluid, includes fusion grooves 43 a recessed along edges thereof so as to correspond to the fusion ridges 42 a , outer pocket flanges 43 b and guide ridges 43 c . The outer pocket flanges protrude to the first housing 42 on outer sides of the fusion grooves 43 a so as to be spaced apart from the fusion ridges 42 a of the first housing 42 by a predetermined distance. The guide ridges 43 c protrude from the first surface 431 to the first housing 42 on inner sides of the fusion grooves 43 a and closely contact the inner pocket ridges 42 b of the first housing 42 . Grooves 433 are formed on the second surface 432 at positions corresponding to the guide ridges 43 c , respectively. As shown in FIG. 9 , the grooves 433 extend in a circumferential direction of the balancer 40 . Each of the grooves 433 includes an inclination surface 434 that is inclined toward a bottom thereof. Meanwhile, the first surface 431 of the second housing 43 includes a portion 435 that protrudes toward the first housing 42 . The guide ridges 43 c protrudes from the protruding portion 435 of the first surface 431 toward the first housing 42 .
The guide ridges 43 c of the second housing 43 move in contact with the inner pocket ridges 42 b of the first housing 42 when the second housing 43 is fitted into the first housing 42 , to thereby guide the fusion ridges 42 a of the first housing 42 to be fitted into the fusion grooves 43 a of the second housing 43 rapidly and precisely.
Thus, when the fusion ridges 42 a of the first housing 42 are fitted into the fusion grooves 43 a of the second housing 43 in order to fuse the first housing 42 with the second housing 43 , as shown in FIG. 10 , an inner pocket 40 b having a predetermined spacing is formed between the fusion ridges 42 a and inner pocket ridges 42 b , and an outer pocket 40 c having a predetermined spacing is formed between the fusion ridges 42 a and the outer pocket flanges 43 b.
In this state, when heat is generated between the fusion ridges 42 a of the first housing 42 and the fusion grooves 43 a of the second housing 43 , the fusion ridges 42 a and the fusion grooves 43 a are firmly fused with each other. At fusion, fusion scraps that are generated by heat and fall down inward of the first housing 42 are collected in the inner pocket 40 b , so that the scraps are not introduced into the internal space 40 a of the balancer 40 in which the balls 41 move. Fusion scraps falling down outward of the first housing 42 are collected in the outer pocket 40 c , and thus are prevented from falling down outward of the balancer 40 .
In the embodiments, the balancers 20 , 30 and 40 have been described to be installed on a drum type washing machine by way of example, but it is apparent that the balancers can be applied to an upright type washing machine having a structure in which a spin tub is vertically installed.
As described above in detail, the washing machine according to the embodiments of the present invention has a high-strength structure in which at least one balancer is provided with at least one support protruding outward from the wall thereof, so that, although the strong centrifugal force acts on the wall of the balancer due to a plurality of balls making a circular motion in the balancer, the wall of the balancer is not deformed. Thus, the plurality of balls can make a smooth circular motion without causing excess vibration and noise, and thus increasing the durability and life span of the balancer.
Further, the washing machine according to the embodiments of the present invention has a structure in which the balancer can be rapidly and exactly positioned in the recess of the spin tub by the supports, so that an assembly time of the balance can be reduced.
In addition, the washing machine according to the present invention has a structure in which fusion scraps generated when the balancer is fused are collected in a plurality of pockets, and thus are prevented from falling down inward and outward of the balancer, so that the internal space of the balancer, in which a plurality of balls are filled and move in a circular motion, has a smooth surface without the addition of fusion scraps. As a result, the balls are able to move more smoothly, and excess noise and vibration are minimized. The balancer may have a clear outer surface to provide a fine appearance without the fusion scraps, so that it can be exactly coupled to the spin tub without obstruction caused by the fusion scraps.
Although a few embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims and their equivalents. | A front loading washing machine including a housing; a water reservoir installed in the housing for containing washing water; a spin tub provided in the water reservoir to hold laundry to be washed, the spin tub having an annular recess and rotating with respect to a horizontal axis of the washing machine; and at least one balancer installed in the annular recess of the spin tub, the balancer comprising an annular shaped race formed of a plastic material. | 3 |
FIELD OF THE INVENTION
Although this invention is directed primarily toward providing a product that is utilized to make containers and packaging with cushioning and insulating characteristics, it may have application to other areas of use such as for toys. However, the invention will be described herein as it is used for packaging.
DESCRIPTION OF THE PRIOR ART
In the packaging industry it has been the practice to use shock-absorbing somewhat rigid or stiff plastic foam members to place around an article in its shipping container, such as a cardboard box, to cushion it to prevent damage during delivery. These members usually are provided in two different forms. One is in the form of individual flat pieces made by molding each piece separately or by die cutting the pieces out of a slab or sheet of plastic foam. The pieces are then placed individually around the article and may be cemented or attached together in some other fashion and then the packaged article is placed in the shipping container. This requires that the fabricator of the protective material first make the separate pieces and then ship them to the packer who selects the proper pieces, puts them together in the right order and attaches them together around the article. The pieces must be made separate because the material is too stiff to fold or bend around an article. This invention provides means whereby the stiff plastic foam effectively becomes foldable. Another way is to mold the protective package in its desired end shape and then place the article inside the package which is then placed in the shipping container. There are a number of difficulties with this latter type of system. For one since generally the protective package is manufactured by a fabricator it has to be shipped to the packer or user. If it is in the package form as described above it is usually quite bulky and, therefore, costly to ship as compared to the first described system where all the pieces are flat and can be stacked for efficient shipping. A second problem is where the protective package has an internal boss or projection. This adds to the cost of the mold and to the cost of the molding operation because the mold cavity would have to be separated in order to remove the molded part or the parts would have to be made separately and then joined together.
A partial solution to the problems with the first described system has been to attach the individual flat members to a flat layer of some suitable flexible material which serves as a hinge connection so that the various pieces are kept together and folded into position to form the protective container. U.S. Pat. No. 1,645,765 dated Oct. 18, 1927 by McCree shows a product of this nature having two layers or pieces of material (which assumedly could be protective cushioning material) with a flexible woven fabric or cloth between the layers to provide a hinge connection. While the patent does not describe the manner in which the intermediate layer is attached to the two other separate layers it is assumed that it is done with some suitable adhesive. A drawback of this system is that it requires the steps of making separate pieces for the two separate layers and then adhesively attaching them to opposite sides of a separate layer. Another drawback is that since the end product is made up of individual layers there is the danger of the layers separating, especially as the adhesive deteriorates.
SUMMARY OF THE INVENTION
A slab or sheet of relatively stiff or rigid plastic material, preferably a shock-absorbing cushioning foam, has an embedded flat mesh to provide a hinging layer. The base material is molded into a unitary body by the material fusing together on each side of the mesh through the mesh openings so that the mesh is secured solidly in place and is made a part of the composite body during the molding operation. This eliminates the need for the steps of forming individual pieces, placing a hinging layer between the separate layers of these individual pieces and attaching them together in some fashion. In addition, by molding the plastic material so that it fuses together through the openings in the mesh there is no danger of separation of layers. Either during the molding process or afterwards elongated cutlines are formed through the plastic material down to the mesh so that the plastic sheet is separated into sections which are still hingedly joined to one another so that they can be folded with respect to one another to form the walls of a protective container. Initially the product is made in flat sheet or slab form which can be efficiently stored and shipped and can be later quickly and conveniently folded into the desired package as needed. In addition, if there is a need or desire to have an opening in the protective package for viewing its contents some of the plastic can be eliminated in an area on both sides of the mesh to provide a see-through opening without losing any support or protection for the contents and without substantially weakening the package.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a break-away section view of the preferred embodiment of the invention illustrating in detail the molded form of the plastic sheet or slab;
FIG. 2 shows overlying slots or grooves making the sheet into separate hingedly joined sections;
FIG. 3 illustrates an embodiment having a cutline or groove from only one surface of the sheet;
FIG. 4 shows the two hingedly joined sections of FIG. 2 bent with respect to one another to form walls of a package;
FIG. 5 illustrates the two hingedly joined sections of FIG. 3 folded to form walls of a package;
FIG. 6 illustrates a packaging product made according to the teachings of this invention; and
FIG. 7 illustrates a container made according to the teachings of the invention having a see-through opening for viewing the contents of the container.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The base sheet or board or slab identified by reference numeral 10 is of unitary construction and is molded in the illustrated flat form using a suitable plastic material which has the desired characteristics. Preferably the material is expanded polystyrene foam (EPS) which has cushioning or shock-absorbing characteristics to serve the purpose of protective packaging although polyurethane foam or open cell polyethylene foam are examples of other usable materials. Embedded in the base plastic material between the top and bottom surfaces is a generally flat relatively thin bendable layer of mesh 11. Although the base material 10 is formed into a single integral body, for convenience and for purposes of explanation there may be reference from time to time to a top portion 10A and a bottom portion 10B. FIG. 1 illustrates how the top section 10A and the bottom section 10B are fused together through the openings in the mesh 11. The mesh 11 substantially retains its separate identity and is tenaciously held in place within the body 10 by virtue of the fusing of the upper and lower portions 10A and 10B. The body 10 can be formed in conventional fashion by first placing the mesh into a mold cavity then filling the remainder of the cavity with polystyrene beads. The bead size and mesh size are such to permit the beads to go through the mesh openings. In a conventional fashion hot steam that is used to expand the polystyrene beads in the mold passes through the mesh openings and causes the beads to flow and fuse together through the mesh openings and around the mesh lines which define the mesh openings thereby embedding the mesh solidly within the base plastic material.
Either during molding or by use of suitable dies, hot wires or other cutting devices after molding, grooves or slots 12 are formed as desired or as required through the top 10A and bottom 10B portions of the base material in an overlaying relationship down to the web 11. For example, if the sheet were rectangular, grooves 12 extending from one side edge to the other would cut the sheet into two separate pieces which would still be hingedly attached to one another. If, for example, a sheet is to be made into a square box with top and bottom, then a series of slots or grooves 12 would be made in the sheet to form it into the required number of equal dimensioned sections to provide the separate hinged-together pieces. The separate sections, such as 13 and 14, can then be folded along the slots 12 to form the walls of a container with the pieces held together by the mesh 11 as illustrated in FIG. 3. For shipping, the grooved sheets can be laid out flat and stacked and only after arrival at their destination prior to use do they have to be folded to form the desired container or package.
Alternatively, the relatively stiff foam board can be made foldable in the manner illustrated in FIGS. 3 and 5. The plastic mesh 11 is embedded in the foam plastic closer to the lower surface than the upper surface. A cutline or groove 15 is made either during molding or by a suitable cutting tool after molding in the upper section 10A of the plastic board down to the mesh 11. The uncut lower section 10B is now thin enough so that it has some degree of flexibility so that the two sections 16 and 17 can now be folded along slot 15 in the manner illustrated in FIG. 5 and the bottom portion 10B forms a fillet at the corner junction of sections 16 and 17. The location of mesh 11 is determined by the type of material forming the plastic sheet and can be set and controlled to stay in place at this location during the molding process using well-known molding techniques.
FIG. 6 illustrates a particularly advantageous feature of the invention. As an example, the base sheet 10 is molded with a substantially flat upper and lower surface except for upwardly protruding bosses 18 which are needed to hold in place the article which is to be packaged up. The sheet with the bosses can be molded flat as shown in heavy lines in FIG. 6 so the molding process is not any more costly than it would be for a smooth surfaced article. After the grooves 12 are appropriately formed in the base 10 the separate outer sections 19 can be folded 90° upward, as illustrated in dashed line, to form the walls of a container in which the bosses 18 are appropriately located to hold a particularly shaped article in place within the package.
FIG. 7 illustrates a three sided package (three sides were selected only for purposes of illustration) which is initially molded and formed in accordance with the teachings of the invention as described earlier. In this instance, however, in the areas generally designated by reference numeral 20 in each of the two side panels the plastic has been eliminated thereby providing a see-through opening in these two sidewalls so that the contents of the package can be observed through the openings in mesh 11. This is done without the package losing its ability to hold its contents in place. The opening can be formed either during the molding process or the plastic can be removed later using any conventional means.
As a feature of the invention, it has been found that the embedded mesh 11 also serves to reinforce the plastic so that it is less likely to crack or break or fragment if subjected to undue stress. Even if the plastic cracks the mesh tends to hold the pieces together.
Mesh 11 is preferably made of a suitable plastic but the material must be such so that it does not change substantially when subjected to the temperatures and pressures used in the molding process. Mesh 11 can be made from other materials such as metals but must have enough flexibility to be folded or bent along the grooves to provide the hinging effect.
Although EPS is mentioned as being preferred, one can use liquid plastic material which will flow through the openings in the mesh and be fused together during the molding process. It is also possible that the molding can be done by extrusion whereby the component parts are brought together and the plastic material fused through the mesh openings. Typically, a suitable EPS is a material identified as Arco Chemical D-195B and a suitable plastic mesh is identified as Conwed No. XV-4680.
In addition to its characteristics which make it useful for packaging or for insulated containers, foam plastic is quite bouyant so an article made in accordance with the teachings of this invention can be utilized as a float having a number of hingedly attached sections formed as described hereinabove which would undulate with the waves on water.
While in the illustrations mesh 11 is shown located about half way between the top and bottom surfaces of the base plastic, in some instances it may be preferable to have the mesh located closer to one of the surfaces as described earlier.
Although layer 11 is referred to as mesh, there is no intent to limit it to material which is only known as "mesh". Other perforated materials can be used provided they have the necessary characteristics, such as having openings through which the plastic material can be fused, having at least some degree of flexibility so that it can be bent along the slots or grooves, not reacting adversely with the plastic sheet material and not being subject to major alteration during molding or cutting.
Although the invention described showing a single hinging mesh embedded in the plastic material multiple additional mesh layers can be utilized. Also, the mesh need not be continuous throughout the molded sheet. Mesh need only be present where the slots or grooves are formed to provide the hinging effect. | A thin mesh is embedded in a relatively rigid molded plastic sheet which has cushioning and insulating characteristics with cutlines formed through the plastic to the mesh so that the sheet is separated into hingedly attached sections which can then be folded as desired to make containers or packages or the like. As an additional feature the plastic can be eliminated over certain areas on both sides of the mesh to provide a see-through opening. | 1 |
RELATED APPLICATIONS
This application claims the benefit of United States Provisional Application Ser. No. 60/038,966 filed Feb. 24, 1997.
BACKGROUND OF THE INVENTION
This invention relates generally to an apparatus used to clean an aqueous solution of unwanted particulate and more particularity relates to a magnetic separator apparatus used to clean an aqueous solution of unwanted magnetic particulate by using a conveyor chain with polypropylene bars having an unique configuration of barium ceramic magnets incorporated therein. This magnetic separator apparatus may be continuously run through the "dirty" solution. In particular, such an aqueous solution is used to clean car and truck bodies and other component parts prior to being immersed into zinc phosphate and zinc chromate baths used to coat the surfaces of these parts and assemblies.
There are many common methods and means used in the prior art to clean aqueous solutions of unwanted particulate. One traditional method is the insertion of magnetic rods directly into the aqueous solution. This type of cleansing system, however, is flawed because of the necessity to frequently manually remove the rods with accumulated metal particulate deposits. These rods must then be cleansed of unwanted particulate and then inserted back into the aqueous solution. As can be appreciated by those skilled in the art, this method of cleaning is time-consuming and labor-intensive. It will be understood that another flaw found in this prior art methodology is that the effectiveness of the magnets used to remove dirt and the like from the solution is greatly diminished as magnetic dirt deposits accumulate on the rods.
Another type of system known in the art that is used to cleanse aqueous solutions of unwanted particulate is the passage of a stainless steel conveyor belt impregnated with magnets through the solution. This type of cleaning system, however, does not adequately and efficiently clean the aqueous solution of all unwanted particulate. This cleaning process is not efficient because the effectiveness of the magnets is drastically reduced by the total encasement of the magnets in the stainless steel conveyor belt. Thus, this type of design reduces the strength of the magnetic fields emanating from the magnets.
Accordingly, these limitations and disadvantages of the prior art are overcome with the present invention, and improved means and techniques are provided which are useful for cleaning an aqueous solution of unwanted magnetic particulate.
SUMMARY OF THE INVENTION
The present invention provides an improved magnetic separator apparatus that overcomes deficiencies in the prior magnetic separator art. As will be hereinafter described in detail, the present invention teaches an unique configuration of magnets impregnated into polypropylene bars that are, in turn, disposed in a spaced-apart relationship upon a conveyor belt disposed in an aqueous solution.
Under the present invention, barium ceramic magnets are impregnated into a plurality of polypropylene bars. The added strength of the barium ceramic magnet means and the unique configuration of these magnets optimize the field penetration and holding strength engendered by these magnets.
It is an object of the present invention to provide an apparatus for continuously cleaning aqueous solutions containing unwanted magnetic particulate.
It is another object of the present invention to provide a magnetic separator apparatus for purging magnetic particulate from an aqueous solution.
It is still another object of the present invention to provide an apparatus for purging magnetic particulate materials from an aqueous solution without requiring human intervention to remove accumulated dirt from the magnetic separation means.
It is yet another object of the present invention to provide an apparatus for purging magnetic particulate materials from an aqueous solution while requiring only minimal maintenance attributable to accumulated dirt forming on the magnetic separation means.
It is an object of the present invention to provide a magnetic separation apparatus for cleaning magnetic particulate materials from an aqueous solution which engenders maximum reach of the magnetic field.
It is a specific object of the present invention to provide an apparatus for separating unwanted magnetic particulate from an aqueous solution, said apparatus comprising: a plurality of spaced-apart magnetic means disposed upon a conveyor belt means for attracting said magnetic particulate; said conveyor belt means disposed within said aqueous solution and configured for movement therethrough; each of said plurality of magnetic means constructed of polypropylene embedded with a like plurality of pairs of magnetic bars disposed on each side of a longitudinal axis of said conveyor belt means; and scraper means fixedly attached to said conveyor belt means for removing said particulate from said plurality of magnetic means for deposit into collection means.
It is another specific object of the present invention to provide an apparatus for separating unwanted magnetic particulate from an aqueous solution, said apparatus comprising: a plurality of spaced-apart magnetic means disposed upon a conveyor belt means for attracting said magnetic particulate; said conveyor belt means disposed within said aqueous solution and configured for movement therethrough; each of said plurality of magnetic means constructed of polypropylene embedded with a like plurality of pairs of magnetic bars disposed on each side of a longitudinal axis of said conveyor belt means; each of said plurality of pairs of magnetic bars having: a first barium ceramic magnet having a top and bottom surface; a second barium ceramic magnet having a top and bottom surface; and with said bottom surface of said first barium ceramic magnet disposed abutably of said top surface of said second barium ceramic magnet, so that the South Pole of said first barium ceramic magnetic is aligned and contiguous with the South Pole of said second barium ceramic magnet; and scraper means fixedly attached to said conveyor belt means for removing said particulate from said plurality of magnetic means for deposit into collection means.
It is still another specific object of the present invention to provide an apparatus for separating unwanted magnetic particulate from an aqueous solution, said apparatus comprising: a plurality of spaced-apart magnetic means uniformly disposed upon a conveyor belt means for attracting said magnetic particulate; said conveyor belt means disposed within said aqueous solution and configured for movement therethrough; each of said plurality of magnetic means constructed of polypropylene embedded with a like plurality of pairs of magnetic bars disposed on each side of a longitudinal axis of said conveyor belt means; each of said plurality of pairs of magnetic bars having: a first barium ceramic magnet having a top and bottom surface; a second barium ceramic magnet having a top and bottom surface; and with said bottom surface of said first barium ceramic magnet disposed abutably of said top surface of said second barium ceramic magnet, so that the South Pole of said first barium ceramic magnetic is aligned and contiguous with the South Pole of said second barium ceramic magnet; each of said sets of pairs of said plurality of pairs of magnetic bars embedded in each of said plurality of spaced-apart magnetic means is disposed symmetrically of said longitudinal axis of said conveyor belt means; and scraper means fixedly attached to said conveyor belt means for removing said particulate from said plurality of magnetic means for deposit into collection means.
These and other objects and features of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings with like numerals referring to like components.
IN THE DRAWINGS
FIG. 1 depicts a right side elevation view of the preferred embodiment of the present invention.
FIG. 2 depicts a right side elevation view of a portion of the preferred embodiment depicted in FIG. 1.
FIG. 3 depicts a right side isolated elevation view of a portion of the preferred embodiment depicted in FIG. 2.
FIG. 4 depicts an isolated plan view of a portion of the preferred embodiment depicted in FIG. 2.
FIG. 5 depicts another right side isolated elevation view of a portion of the preferred embodiment depicted in FIG. 2.
FIG. 6 depicts a simplified frontal perspective view of a pair of magnetic means under the present invention.
FIG. 7 depicts a frontal perspective view of the preferred embodiment of the polypropylene bars depicted in FIGS. 1-3, showing the disposition of magnetic means therein.
DETAILED DESCRIPTION
Referring now collectively to FIGS. 1-5, there is illustrated the preferred embodiment of a magnetic separator device of the present invention. Magnetic separator device 100 of the present invention consists of preferably stainless steel conveyor belt means 50 continuously moving through a vessel (not shown) holding aqueous solution. It will be understood that U.S. Pat. No. 4,055,497 generally describes the state of the conveyor belt art applicable to a settling tank. Thus, conveyor belt means 50 passes through upper housing 60 and lower housing 70 in a manner well known in the art. As will be hereinafter described, according to the teachings of the present invention, stainless steel conveyor belt means 50 should preferably be configured with a plurality of spaced-apart magnetic means 80 comprising plurality of barium ceramic magnet means 90 impregnated into a polypropylene bar. Motor and concomitant gearbox 22 driving conveyor belt means 50 are located in upper housing 60. A conventional external power supply line provides the electrical or pneumatic power to drive motor 22. As will be appreciated by those skilled in the art, blade scraper assembly 19 containing plurality of scraper blade means 18 is also located in the interior of upper housing 60.
It will further be seen that preferred embodiment 100 comprises frame with lid 1, mounting clip means 2, adjustable bottom support means 3, bushing block cover means 4, tension adjustment clip means 5, plurality of spaced-apart magnetic block means 6A, B, C, D, . . . N, O and idler shaft 7 and associated idler chain 8, magnetic block means 9, secondary sprocket means (including return, guide, and feed) 10, drive sprocket means 11 and associated drive shaft 12 and concomitant drive shaft bearings 13, guide shaft 14, guide shaft bushing block means 15, feed shaft 16 and associated feed shaft bearings 17, plurality of scraper blade means 18 and associated plurality of blade holder assemblies 19, scraper sludge collection drawer means 20, excess fluid drain plug means 21, motor and associated gearbox shelf 22, filter means 23, regulator 24, lubricator 25, pressure gauge 26, air or electric line kit 27 and associated air or electric motor 28, motor riser block 29, motor/reducer coupling means 30 and concomitant reducer gearbox 31, reducer/drive shaft coupling means 32, silencer/reclassifier 33, and coupling guard assembly 34.
As will be evident to those skilled in the art, motor 22 drives conveyor belt means 50 with plurality of spaced-apart magnet means 80 downwardly at an angle into the vessel holding the aqueous solution, so that the solution may be cleansed of metal particulate. After passing through the solution, the metal particulate will naturally adhere to plurality of sections 6A, B, C, D, E, F, G, H, I, J, K, L, M, N, and O of conveyor belt means 50 having the magnet means taught by the present invention contained thereon. The motor continues to drive conveyor belt means 50 and simultaneously drives the unwanted metal particulate up and out of the vessel and towards upper housing 60. In a manner common in the art, plurality of scraping means 18 located in upper housing 60 will then scrape the accumulated metal particulate off the conveyor belt and into collection bin 20. Collection bin 20, of course, may be emptied at a later time whenever necessary.
It has been found that the infirmity of the prior art, wherein unwanted particulate deposits upon magnetic separation means thereby adversely affecting the separation capability, may be effectively overcome by a combination of a novel arrangement of the magnetic separation means and by suitably coating this magnetic separation means. According to the preferred embodiment of the present invention, by configuring conveyor belt means 50 with plurality of spaced-apart permanent magnetic means 80 comprising barium ceramic material, separation of metal particulate contemplated hereunder may be accomplished with an efficiency heretofore unknown in the art.
Now referring to FIGS. 6 and 7, there is illustrated the unique configuration of the plurality of polypropylene bars 6A-O attached to stainless steel conveyor belt means 50. FIG. 7 illustrates the configuration of each of the polypropylene bars 80 impregnated with ceramic barium magnet means M, illustrated in FIG. 6. Each of the barium ceramic magnet pair M--depicted in FIG. 7 as M' and M" for clarity--is embedded into each respective open area 95 disposed on either side of polypropylene bar 80 shown in FIG. 7. It should be evident that space 95 is configured to abuttably receive magnetic means M.
Referring specifically to FIG. 6, there is illustrated the unique configuration of each of the plurality of ceramic barium magnet means impregnated into plurality of polypropylene bars 6A-O attached to stainless steel conveyor belt means 50. Thus, magnet means pair M, comprising upper magnet means M1 and lower magnet means M2--having similar height, width and length--are oriented so that the magnetic poles normal to the widest surface are forced together against like poles. In particular, the bottom surface of magnet block M1 is disposed upon the top surface of magnet block M2 so that their respective South Poles are contiguous.
Accordingly, the North Pole of magnet block M1 is directed normally away from its top surface and the North Pole of magnet block M2 is directed normally away from its bottom surface. The unique configuration taught by this invention, wherein magnetic means are imbedded into a plurality of polypropylene bars, has been found to increase the field strength or holding power and reaching power of the pairs of barium ceramic magnets M1 and M2. It has also been found that, for the configuration shown in FIGS. 6 and 7, a 10 inch field reach has been achieved at 1 Gauss unit. More particularly, for the preferred embodiment, M1 and M2 are composed of two 3/8 inch tall by 3/4 inch wide by 2 inches long barium ceramic magnets having the polarization normal to the 3/4 inch wide surfaces that are forced together with the respective South Poles turned in. During testing, the field strength of this magnetic configuration was compared to the field strength of a conventional single 3/4 inch tall by 3/4 inch wide by 2 inches long solid barium ceramic magnet with poles normal to the 3/4 inch surfaces. Both magnet arrangements had very good field strength.
Similarly, the linear reaching power of these two test magnet configurations was tested. While the linear reaching power of the conventional single solid barium ceramic magnet was only eleven inches, the linear reaching power of the pair of barium ceramic magnets having the unique configuration taught by the present invention was 20 inches. Ergo, it will be appreciated that the magnetic pair of solid barium ceramic magnet means taught by the present invention delivers almost double the linear reaching power of a conventional single similar magnet means.
Other variations and modifications will, of course, become apparent from a consideration of the structures and techniques hereinbefore described and depicted. Accordingly, it should be clearly understood that the present invention is not intended to be limited by the particular features and structures hereinbefore described and depicted in the accompanying drawings, but that the concept of the present invention is to measured by the scope of the appended claims herein. | A magnetic separator apparatus having a configuration of barium ceramic magnets impregnated into polypropylene bars interspersed onto a conveyor belt which passes through an aqueous solution containing unwanted magnetic particulate. A plurality of spaced-apart magnet pairs embedded in each polypropylene bar are configured to provide maximum field penetration and holding strength of the magnets. Particulate attracted to the plurality of magnet pairs are scraped from the conveyor belt into a collection drawer. | 1 |
[[0001]] The invention was made with Government support under Contract DE-FC36-00G10596, A000, awarded by the U.S. Department of Energy. The Government has certain rights in the invention.
TECHNICAL FIELD
[0002] The present invention pertains to methods of processing plant material and methods of producing compounds from plant material.
BACKGROUND OF THE INVENTION
[0003] Industrial processing of corn material and other plant material currently produces primarily starch with an accompanying large volume of fiber byproduct. Despite the presence of useful components within the fiber byproduct, most of the fiber byproduct is utilized only as a low value component in livestock feed. The usefulness of the plant fiber byproduct is currently limited by a lack of developed methods for processing the plant fiber material to produce the useful compounds contained therein.
[0004] It would be desirable to develop methods of producing useful compounds from plant materials.
SUMMARY OF THE INVENTION
[0005] In one aspect, the invention encompasses a method of processing plant material. Depending upon the initial water content, an amount of water can be added to the plant material to form a mixture. The mixture is separated into a liquid component and a solid-containing component. At least one of the liquid component and the solid-containing component undergoes additional processing. Processing of the solid component produces oils, and processing of the liquid component produces one or more of ethanol, glycerol, ethylene glycol propylene glycol and lactic acid.
[0006] In one aspect, the invention encompasses a process of forming one or more of glycerol, ethylene glycol, lactic acid and propylene glycol from plant matter. Water can be added to plant matter as needed to form a mixture. The mixture is heated and filtered and the filtrate is retained. The filtrate contains hemicellulose, fragments of hemicellulose and starch. At least some of the hemicellulose and fragments of the hemicellulose are converted to diols, linear polyalcohols and/or lactic acid. At least some of the linear polyalcohols are cleaved to produce one or more of glycerol, ethylene glycol, propylene glycol and lactic acid.
[0007] In one aspect, the invention encompasses a method of recovering sterols. A material containing plant fiber can be mixed with water to form a mixture. The mixture is heated and filtered to produce a filtrate and a solid-containing portion. The solid-containing portion is treated with one or more solvents to extract a material containing one or more free or complexed sterols, stanols or triglycerides.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Preferred embodiments of the invention are described below with reference to the following accompanying drawings.
[0009] FIG. 1 is a flowchart diagram of a preliminary processing method of the present invention.
[0010] FIG. 2 is a flowchart diagram of step 100 depicted in FIG. 1 .
[0011] FIG. 3 is a flowchart diagram of a processing method of the present invention.
[0012] FIG. 4 is a flowchart diagram of step 300 of the processing method shown in FIG. 3 .
[0013] FIG. 5 is a flowchart diagram of a particular processing sequence of the present invention.
[0014] FIG. 6 is a flowchart diagram of step 800 of the processing sequence shown in FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The invention encompasses methods which can be utilized for generating compounds from plant materials. A preliminary processing method encompassed by the present invention is described with reference to FIG. 1 . In an initial solubilization step 100 of the preliminary processing, plant material is at least partially is solubilized. In a separation step 200 , the plant material solubilized in step 100 is separated into liquid and solid-comprising components.
[0016] Step 100 of FIG. 1 is described in greater detail with reference to FIG. 2 . The plant material solubilization step 100 initially involves a plant material providing step 110 . The plant material provided in step 110 is not limited to a specific plant type and can include, for example, material from one or more of corn, soybean, rice, barley, oats, chicory, wheat, and sugar beet. A mixture comprising the provided plant material and a liquid can be formed in an optional mixture formation step 130 . Preferably, step 130 comprises the addition of water to form an aqueous mixture having a final water content of from about 50% to about 90%, by weight. Where the plant material provided in step 110 comprises a water content within the desired range, step 130 can be omitted.
[0017] Mixture formation step 130 can comprise forming the mixture to have a pH of from about 1 to about 11, preferably from about 1.5 to about 6.0. Although the pH of the mixture will typically fall within the desired range without adjustment after the addition of water, it is to be understood that the pH of the resulting mixture can be adjusted to fall within this range of pH by addition of one or more of an acid and a base.
[0018] As shown in FIG. 2 , providing plant material can optionally comprise destarching the plant material in a destarching step 120 . The present invention encompasses methods that utilize both step 120 and step 130 , methods that utilize only one of step 120 and step 130 , and methods that omit both step 120 and step 130 . It is to be understood that methods of the present invention can be used to treat either destarched plant material or plant material that has not undergone a destarching treatment.
[0019] For purposes of the present invention, destarched plant material can comprise plant material which has at least some of the original starch content removed. In particular aspects, destarched plant material can have greater than or equal to about 80% of the original starch content removed. Removal of starch from plant material can be achieved by a variety of conventional methods known to those of ordinary skill in the art. After the destarching step 120 , the destarched plant material can be used in step 130 to form an aqueous mixture of destarched plant material.
[0020] As shown in FIG. 2 , a hydrolysis step 140 can be performed during plant material solubilization. Hydrolysis step 140 can hydrolyze at least some of the polysaccharides in the plant material mixture. Hydrolysis step 140 can comprise, for example, heating of the plant material. Step 140 can alternatively or additionally comprise addition of an acid in an amount appropriate to adjust the pH of the mixture to a pH of from about 1 to about 3. Numerous acids are available for use in hydrolysis step 140 such as, for example, sulfuric acid, carbonic acid, phosphoric acid, lactic acid, nitric acid, acetic acid, hydrochloric acid, and mixtures thereof.
[0021] In embodiments of the present invention where it is desirable to selectively produce polysaccharides such as, for example, partially-hydrolyzed hemicellulose, it is advantageous to avoid addition of acid or base during solubilization step 100 of the preliminary processing. When the solubilization step 100 is performed utilizing an aqueous mixture comprising a pH between about 1 and about 12 (preferably from about 1.5 to about 6.0), greater than or equal to about 75% of hemicellulose comprised by the mixture can be solubilized while predominantly retaining a polymeric form throughout solubilization step 100 .
[0022] The plant material mixture formed in step 130 can undergo solubilization from between about 1 minute to about 2 hours, preferably from between about 5 minutes to about 1 hour. Where acid has not been added, the temperature during solubilization can be from about 100° C. to about 200° C., preferably from between about 120° C. to about 180° C., and more preferably from about 140° C. to about 160° C. If acid is added during step 140 , the solubilization temperature can be from about 100° C. to about 200° C., preferably from 120° C. to about 180° C., and more preferably from 120° C. to 160° C.
[0023] As shown in FIG. 1 , a separation step 200 can be performed after solubilization step 100 . Separation step 200 can comprise, for example, one or more of centrifugation, pressing, and filtration. Separation step 200 can produce a liquid-comprising portion or filtrate, and a solid-comprising component. The liquid component 210 and the solid-comprising component 220 can independently undergo further processing as discussed below.
[0024] The filtrate or liquid component produced by the separation step 200 can comprise, for example, one or both of polysaccharides and monosaccharides. As discussed above with respect to plant material solubilization step 100 depicted in FIG. 2 , the relative amount of monosaccharides and polysaccharides present in the liquid component will depend upon conditions utilized during the solubilization step. The saccharides present in the liquid component can comprise, for example, partially hydrolyzed starch, partially hydrolyzed hemicellulose, polymeric fragments of hemicellulose, and monosaccharide components of hemicellulose. The filtrate can also comprise polysaccharides and monosaccharides of non-hemicellulose origin such as, for example, monosaccharide and polysaccharide breakdown products of starch and cellulose present in the plant material. As shown generally in FIG. 3 , liquid component can be subjected to reduction step 400 to chemically reduce at least some of the saccharides present in the filtrate.
[0025] As indicated generally in FIG. 3 , processing of the liquid component 210 can comprise an initial processing step 300 prior to saccharide reduction step 400 . Step 300 is described in more detail with reference to FIG. 4 . The liquid portion of separation step 200 can be collected in liquid collection step 310 and a neutralization step 320 can be performed if necessary, to adjust the pH of the collected liquid to between about 3 and 8, preferably to a pH of from about 4.5 to about 6.5. Neutralization step 320 can be utilized, for instance, when the preceding processing comprises an addition of acid. It can be advantageous to perform neutralization step 320 prior to a reduction step 400 or a hydrogenolysis step 500 shown in FIG. 3 (discussed below) to alleviate or avoid detrimentally effecting catalyst activity during the reduction or hydrogenolysis.
[0026] Referring again to FIG. 4 , the liquid collected in step 310 can optionally undergo a pretreatment step 330 . As shown in FIG. 4 , pretreatment can occur prior to neutralization step 320 . Alternatively, pretreatment step 330 can be performed after neutralization step 320 . Pretreatment step 330 can comprise, for example, at least one of ultra filtration, carbon filtration, anion exchange chromatography, cation exchange chromatography, and a treatment comprising chemical adjustment followed by precipitation and subsequent separation, where chemical adjustment can include but is not limited to affecting solubility by changing the pH or by addition of a divalent cation. When pretreatment comprises ultra filtration, the ultra filtration can comprise filtration using a molecular weight cutoff filter size of from 2,500 to 50,000. Pretreatment step 330 can remove greater than or equal to 90% of any protein, hydrolyzed protein and/or amino acids present in the liquid solution. It can be advantageous to remove protein from the solution prior to subsequent reduction or hydrogenolysis steps (discussed below) to alleviate or avoid detrimentally effecting or deactivating a catalyst utilized in the reduction or the hydrogenolysis.
[0027] In addition to the feature described above, the formation of liquid component step 300 can optionally include a hydrolysis step 340 . As shown in FIG. 4 , hydrolysis step 340 can be utilized in addition to pretreatment step 330 or can be utilized when pretreatment step 330 is omitted. Where hydrolysis step 340 is utilized in conjunction with pretreatment step 330 , hydrolysis step 340 can occur prior to or subsequent to pretreatment step 330 . Hydrolysis step 340 can hydrolyze at least some of any polysaccharides present in the liquid collected in step 310 . In some instances, it can be advantageous to perform hydrolysis step 340 to hydrolyze polysaccharides present in the solution and thereby minimize any detrimental effect polysaccharides may have on the activity of a catalyst used in subsequent processing steps.
[0028] Hydrolysis step 340 can comprise an addition of an acid or a base. Preferably, hydrolysis step 340 utilizes an acid which can comprise, for example, one or more of sulfuric acid, carbonic acid, phosphoric acid, lactic acid, nitric acid, acetic acid, hydrochloric acid, and mixtures thereof. It can be preferable in some instances to use an acid other than sulfuric acid to alleviate detrimental effects sulfate may have on catalysts utilized in subsequent processing steps according to the present invention. In embodiments utilizing acidic hydrolysis step 340 , the pH of the solution during the hydrolysis step can preferably be between about pH 1 and about pH 5, and more preferably between about pH 1.5 and pH 2.5.
[0029] An effective temperature for purposes of hydrolysis step 340 can be between from about 100° C. to about 200° C., preferably from about 120° C. to about 160° C., and more preferably from between about 120° C. through about 140° C. It can be beneficial to perform hydrolysis step 340 to decrease the high temperature requirements during a subsequent reduction step, discussed below. In embodiments of the present invention where hydrolysis step 340 is utilized, neutralization step 320 can comprise to readjustment of the pH of the liquid to between about 3 and 7, preferably to a pH of from about 4.5 to about 6.5, prior to subsequent processing steps.
[0030] Referring again to FIG. 3 , initial processing of the liquid component can be followed by reduction step 400 . Reduction step 400 can comprise chemical reduction of saccharides by, for example, hydrogenation conditions which can convert at least some of any monosaccharides and polysaccharides present in the liquid component into the respective linear polyalcohols. In addition, if polysaccharides are present in the liquid component, hydrolysis to form the respective monosaccharides can occur during the reduction and can be enhanced by an increased reaction temperature.
[0031] Reduction step 400 can comprise catalytic hydrogenation. Catalytic hydrogenation can comprise exposing saccharides to a catalyst comprising a support and one or more members of the groups consisting of Ru, Ni, Pt, and Pd. The catalyst support can comprise carbon and/or other insoluble support material, such as titania and zirconia. Catalytic hydrogenation can comprise a temperature from about 80° C. to about 300° C., preferably from about 100° C. to about 250° C. and more preferably from about 120° C. to about 200° C. A hydrogen pressure during hydrogenation can be from about 100 psig H 2 to about 3,000 psig H 2 , preferably from between about 1,000 psig H 2 and about 2,200 psig H 2 and most preferably from about 1,200 psig H 2 to about 1,800 psig H 2 . Hydrogenation can be performed over a time range of from about 1 minute to about 8 hours, preferably from between about 1 minute and about 4 hours.
[0032] Hydrogenation according to methods of the present invention can produce a total amount of linear polyalcohols which can comprise sorbitol, xylitol and arabinitol as the major polyalcohols present. Sorbitol can comprise from 0% to 100% of the total amount of linear polyalcohols produced, xylitol can comprise from 0% to 100% of the total amount of linear polyalcohols produced, and arabinitol can comprise from 0% to 100% of the total amount of linear polyalcohols produced.
[0033] Referring again to FIG. 3 , after the reduction of saccharides in reduction step 400 , the liquid component can be subjected to a hydrogenolysis step 500 . Hydrogenolysis step 500 can cleave at least some of the linear polyalcohols produced by reduction step 400 to form a group of products that can be collected by collection step 600 (discussed below).
[0034] Hydrogenolysis step 500 can comprise catalytic hydrogenolysis. Catalytic hydrogenolysis can utilize a catalyst such as, for example, a catalyst comprising a support and one or more members of the group consisting of Ru, Ni, Re, and Co. The support can comprise for example, one or more of carbon, titania and zirconia. Catalytic hydrogenolysis step 510 can further comprise utilization of an added base. Assuming a neutral starting pH of from about pH 5 to about pH 8, an appropriate pH for catalytic hydrogenolysis step 510 can be achieved by, for example, an addition sodium hydroxide to a final concentration of from about 0% to about 10% by weight, and preferably from about 0.5% to about 2% by weight, relative to the weight of the final solution.
[0035] As shown in FIG. 3 , reduction reaction step 400 and hydrogenolysis reaction step 500 can be performed individually. Alternatively, the reduction reaction can be combined with hydrogenolysis within a common reaction vessel (not shown) and can utilize a common catalyst. For purposes of a combined hydrogenation/hydrogenolysis, a common catalyst can be, for example, Ru on a carbon support. The conditions for the combined hydrogenation and hydrogenolysis reactions can comprise initial conditions identical to the conditions discussed above with respect to reduction reaction 400 as conducted independently. In the combined reaction, hydrogenolysis can be induced by, for example, an addition of sodium hydroxide into the common reaction chamber. Assuming the solution was neutralized prior to the hydrogenation conditions, sodium hydroxide can be added according to the conditions discussed above with respect to hydrogenolysis reaction step 500 , as conducted independently. The appropriate amount of sodium hydroxide to be utilized for hydrogenolysis reaction, either as performed independently or as combined with reduction reaction 400 , can be varied within the ranges discussed above based upon the pH of the solution prior to addition of the base and the sugar concentration in the solution.
[0036] As shown in FIG. 3 , a product collection step 600 can be performed after hydrogenolysis reaction 500 to collect a group of products. The group of products can comprise one or more of lactic acid, propylene glycol, ethylene glycol and glycerol. A combined amount of ethylene glycol, propylene glycol and glycerol in the liquid component after hydrogenolysis reaction 500 can comprise from about 50% to about 100% of the total amount of carbon present in the liquid component.
[0037] In addition to the features described above, methods of the present invention can include processing of a solid-comprising portion 220 obtained by the separation step 200 shown in FIG. 1 . Methods for processing of the solid-comprising portion according to the present invention are discussed generally with reference to FIG. 5 . An initial processing step 700 can optionally be utilized to remove at least some of any liquid portion present in the solid-comprising component. Initial processing step 700 can comprise removal of some or all of any water present in the component utilizing one or more of filtration, air drying, vacuum drying and heating. Alternatively, subsequent processing of the solid-comprising component can be performed in an absence of any further removal of liquid or additional drying.
[0038] As shown in FIG. 5 , whether or not initial processing step 700 is performed, processing of the solid-comprising component can include an extraction step 800 . Extraction step 800 is discussed in more detail with reference to FIG. 6 . Extraction step 800 can include a first solvent addition step 810 . Numerous suitable solvents are available for purposes of the extraction step, and can include but are not limited to one or more of hexane, ethyl acetate, methylene chloride, and acetone. Solvent can be added to provide a volume to mass ratio of from about 1:1 to about 20:1, where the volume is the volume of the added solvent and the mass is the mass of the solid-comprising component prior to solvent addition. In particular processing events, the volume to mass ratio can preferably be about 10:1. The extraction can be conducted for a time of from a few seconds to several hours. Additionally, the extraction can be conducted batchwise or utilizing a continuous process. Extraction step 800 can comprise a first solvent separation step 820 to separate the first solvent from a non-solubilized portion of the solid component. A collection step 830 can be utilized to collect a solubilized component in the separated first solvent.
[0039] As shown in FIG. 6 , the non-solubilized portion of solvent separation step 820 can be retained in a retention step 840 . An optional second solvent addition step 850 can be performed and can utilize the conditions discussed above with respect to the first solvent addition. After a second solvent addition, a second solvent separation step 860 can be performed and the second solvent portion containing a second solubilized component can be recovered. The second solubilized component can be combined with the first solubilized component in a combination step 870 which combines the solvent collected in step 830 with the solvent collected from separation step 860 . Alternatively the first solvent collected in 830 and the second solvent collected in 860 can remain separate. It is to be noted that the solvent used for addition of solvent step 810 and the solvent used for the second solvent addition step 850 can be identical or can be different. Further, the first solvent collected in step 830 can comprise a product material that is different than the product material extracted by the second solvent addition.
[0040] As shown in FIG. 6 , extraction step 800 can comprise one or two additions of solvent steps 810 and 850 . It is to be understood that the present invention can encompass methods utilizing greater than two solvent addition steps (not shown). It can be advantageous to utilize a plurality of solvent additions and separation steps to maximize product extraction.
[0041] Referring again to FIG. 5 , after extraction step 800 , the extracted products can be collected in a collection step 900 . The extracted products collected in step 900 can be from about 3% to about 5% of the initial plant material by weight, or alternatively up to 100% of available extractables. The extracted product can comprise, for example, one or more of campesterol, campestanol, stigmasterol, sitosterol, sitostanol, tocopherols and triglycerides.
[0042] In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents. | The invention includes methods of processing plant material by adding water to form a mixture, heating the mixture, and separating a liquid component from a solid-comprising component. At least one of the liquid component and the solid-comprising component undergoes additional processing. Processing of the solid-comprising component produces oils, and processing of the liquid component produces one or more of glycerol, ethylene glycol, lactic acid and propylene glycol. The invention includes a process of forming glycerol, ethylene glycol, lactic acid and propylene glycol from plant matter by adding water, heating and filtering the plant matter. The filtrate containing starch, starch fragments, hemicellulose and fragments of hemicellulose is treated to form linear poly-alcohols which are then cleaved to produce one or more of glycerol, ethylene glycol, lactic acid and propylene glycol. The invention also includes a method of producing free and/or complexed sterols and stanols from plant material. | 2 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to semiconductor devices such as integrated circuits, and more particularly to the thermal management of such devices.
[0003] 2. Description of the Related Art
[0004] It is well known that many semiconductor packages, whether containing integrated circuits or individual devices such as power transistors, dissipate sufficient heat to require thermal management utilizing heat sinks. In particular, there has been increased emphasis on thermal management in integrated circuit (IC) packaging design stemming from the rapid growth of the number of active circuit elements per chip or die without a corresponding increase in die surface area. The resulting closer spacing of the circuit elements coupled with their higher switching speeds have led to dramatic increases in heat densities. The objective of thermal management in the design of IC packaging is to maintain the operating temperature of the active circuit or junction side of the IC die low enough (for example, 110° C. or below) to prevent premature component failure.
[0005] Traditional methods of reducing the maximum junction temperature include lowering the thermal resistance attachment between the die and the package cover/heat spreader, improving heat sink efficiency, increasing package cover thermal conductivity, reducing the thermal resistance between the package cover and heat sink, and/or improving the cooling air flow inside the electronic system incorporating the IC package. For a device with extreme cooling requirements, an active or passive refrigeration system thermally coupled to the cover of the package is sometimes used. These traditional thermal management techniques, however, often increase the size and weight of the electronic system, can be expensive to implement and may risk compromising device reliability.
[0006] When surfaces having different thicknesses and conductivities are joined together as in an IC device package, the concept of thermal resistance is useful for analyzing the heat flow. Thus, the overall thermal resistance can be modeled as the sum of three thermal resistances arranged in series between the junction or active circuitry side of the IC die and the outside surface of the cover: the thermal resistance of the die itself, the thermal resistance of the die/cover attachment interface material, typically a conductive epoxy, and the thermal resistance of the cover. The thermal resistances are functions of the thermal conductivities of the materials involved which, for the materials used in IC device packaging, have a broad range. Metals, of course, are the best conductors of heat while the conductive epoxies used, for example, to bond the die to the inside surface of the device cover are the poorest heat conductors. Thus, the thermal bottleneck in removing heat from an IC device is the interface between the IC die and the package cover. The problem of heat dissipation is exacerbated in the case of large, high power IC devices such as very large scale integration (VLSI) integrated circuit central processing units (CPUs). Because the dies of such units are relatively thin (for example, 0.76 mm thick), the IC die itself can provide only limited heat spreading. This can cause significant variations in local heat dissipation on the die surface leading to large surface temperature gradients in the case of a VLSI integrated circuit die having high power circuits along an edge or adjacent a corner thereof. This asymmetry, illustrated by prior art FIGS. 1 - 4 , tends to diminish or may completely eliminate heat spreading through the die in one or two directions.
[0007] [0007]FIG. 1 shows a simplified cross section view of a conventional integrated circuit device package 10 containing an IC die 12 in the form of a flip-chip VLSI CPU. FIG. 2 is a bottom plan view of the IC die 12 . The IC device package 10 includes a package substrate 14 made of a ceramic such as alumina and having an upper surface 16 carrying the IC die 12 .
[0008] The die 12 basically comprises a substrate 18 of semiconductor material, typically lightly-doped silicon, having a periphery 20 and opposed, parallel, major surfaces, namely, an upper surface 22 and a lower surface 24 , also referred to as the junction side or underside of the die 12 . In accordance with a typical example of a conventional VLSI CPU, the IC die 12 has a square configuration measuring 22×22 mm, with the periphery 20 thus comprising four edges 20 a - 20 d.
[0009] With reference to FIG. 2, formed within an area 26 on the underside 24 of the semiconductor substrate 18 using well-known integrated circuit fabrication techniques, are numerous circuit features including regions defining junctions of active circuit elements. The circuit area 26 occupies essentially the entire surface area of the underside 24 of the semiconductor substrate 18 . Thus, the circuit area 26 has a boundary 28 substantially congruent with the periphery 20 of the semiconductor substrate 18 . (A very small inactive semiconductor border, that is, a border devoid of active circuit elements typically having a width of about 50-200μ for a 22×22 mm die, may exist around the area 26 .) In the example under consideration, high power active circuit elements, shown schematically as a block 29 , within the area 26 adjoin the portion of the boundary 28 immediately adjacent the edge 20 a.
[0010] With reference again to FIG. 1, the IC die 12 is mechanically and electrically connected to the upper surface 16 of the package substrate 14 by means of an underfilled control collapse chip connection (C4) 30 coupling the junction side 24 of the die 12 to metalization on the upper surface 16 of the package substrate 14 . The space between the die underside 24 and the upper surface 16 of the package substrate is filled with a compliant, non-conductive epoxy 32 . As is known in the art, in C4 technology the die is flipped upside down to provide direct, very low inductance electrical connections between the circuit elements on the underside 24 of the die and the package substrate 14 .
[0011] In the example under consideration, the underside 24 of the IC die has a land grid array (LGA) of signal pads or contacts in registration with a matching array of pads or contacts on the upper surface 16 of the package substrate 14 . The package substrate 14 typically comprises a multilayer assembly that interconnects the LGA on the upper surface of the package substrate 14 with a larger LGA of signal pads on the underside of the package substrate. This physically larger LGA may be connected to a host or higher assembly such as a printed circuit board 36 by means of an LGA interposer socket 38 .
[0012] A cover 40 is attached to the package substrate 14 and includes an inner surface 42 defining with the upper surface 16 of the package substrate 14 an interior cavity or space 44 enclosing the IC die 12 . The cover 40 is fabricated of a heat conductive material such as aluminum silicon carbide. A compliant heat transfer interface 46 , such as a silver filled epoxy, is interposed between and thermally couples the upper surface 18 of the semiconductor die 12 and the inner surface 42 of the cover 40 .
[0013] [0013]FIG. 3 shows an example of the asymmetric power distribution seen on the junction side 24 of the large integrated circuit die 12 depicted in FIGS. 1 and 2 and having high power circuits along the edge 20 a . As can be seen from the power map in FIG. 3, there are large variations in power density or heat flux across the integrated circuit die underside, with the highest concentration thereof existing along the edge 20 a adjacent the high power circuits.
[0014] Through the use of thermal modeling, the temperature distribution across the junction side of the IC die can be mapped, as shown (in ° C.) in FIG. 4, based on the power map of FIG. 3. As expected, the higher power densities along the edge 20 a of the die 12 result in higher temperatures along that edge, and operating temperature gradients of 30 to 40° C., or more, across the die are not uncommon.
SUMMARY OF THE INVENTION
[0015] The present invention reduces the overall thermal resistance of a semiconductor device package so as to improve the thermal performance of the package without any modification of the basic package structure.
[0016] Broadly, in accordance with one exemplary embodiment of the invention, there is provided a semiconductor die comprising a pair of opposed parallel major surfaces and a periphery; an active circuit area within a boundary on one of the major surfaces of the semiconductor die, the active circuit area comprising at least one active circuit element that dissipates heat during operation; and a heat spreading extension disposed between at least a portion of the boundary and at least a portion of the die periphery adjacent the boundary portion, the extension being operable to establish a heat flow path to conduct heat away from the at least one heat dissipating active circuit element.
[0017] Pursuant to another specific embodiment of the invention, there is provided a semiconductor package comprising a package substrate having an upper surface; a thermally conductive cover secured to the package substrate, the cover including an inner surface, the inner surface of the cover and the upper surface of the package substrate defining a space; and a semiconductor die enclosed within the space, the semiconductor die having a major surface and a periphery, the surface of the semiconductor die including an active circuit area comprising at least one active circuit element dissipating heat during operation of the semiconductor package, the active circuit area having a boundary, the surface of the semiconductor die being thermally coupled to the inner surface of the cover and wherein the die includes a heat spreading extension integral with the die, the heat spreading extension being disposed between the boundary of the active circuit area and the periphery of the die, the heat spreading extension being operable to establish a heat flow path to conduct heat away from the at least one active circuit element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Further objects, features and advantages of the present invention will become apparent from the detailed description of the preferred embodiments, below, when taken in conjunction with the accompanying drawings in which:
[0019] [0019]FIG. 1 is a schematic side elevation view, in cross section, showing a conventional integrated circuit package;
[0020] [0020]FIG. 2 is a bottom plan view of the junction side of the IC die incorporated in the package of FIG. 1, as seen along the line 2 - 2 in FIG. 1;
[0021] [0021]FIG. 3 is a power density map for a conventional IC die such as that shown in FIGS. 1 and 2;
[0022] [0022]FIG. 4 is the predicted junction temperature map for the power density map of FIG. 3;
[0023] [0023]FIG. 5 is a schematic side elevation view, in cross section, of an integrated circuit package in accordance with a first preferred embodiment of the invention;
[0024] [0024]FIG. 6 is an enlarged, side elevation view of a portion of the package shown in FIG. 5;
[0025] [0025]FIG. 7 is a bottom plan view of the junction side of the IC die incorporated in the package of FIG. 1, as seen along the line 7 - 7 in FIG. 5;
[0026] [0026]FIG. 8 is a graph showing a specific example of the cooling effect derived from the present invention;
[0027] [0027]FIG. 9 is a bottom plan view of the junction side of an IC die in accordance with a second preferred embodiment of the invention; and
[0028] [0028]FIG. 10 is a bottom plan view of the junction side of an IC die in accordance with a third preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Although the invention will be described in detail in the context of a flip-chip VLSI integrated circuit device package, it will be obvious to those skilled in the art that the invention has broader utility, being applicable to a wide range of semiconductor packages including those for individual high power density semiconductor devices such as high power transistors and laser diodes.
[0030] In the description of FIGS. 5 , et seq., which follows, the same reference numerals used in connection with prior art FIGS. 1 and 2 will be used to designate like elements.
[0031] [0031]FIG. 5 shows, in simplified form, a semiconductor device package 50 in accordance with a first, preferred embodiment of the invention, enclosing a semiconductor die 52 which, as before, may take the form of an integrated circuit such as a flip-chip VLSI CPU. Except for the die 52 , the package 50 , structurally and dimensionally, is basically the same as the conventional package 10 , thus including a package substrate 14 having an upper surface 16 ; a cover 40 ; and an interior space 44 . The IC die 52 device is mounted on the upper surface 16 of the package substrate 14 within the space 44 in the manner described earlier.
[0032] Referring now also to FIGS. 6 and 7, the IC die 52 basically comprises a semiconductor substrate 53 including upper and lower major sides 54 and 56 , respectively, and a periphery 58 . In accordance with the specific example under consideration, the IC die 52 has a rectangular or square configuration in plan view, including four edges 58 a - 58 d . The underside 56 of the IC die 52 comprises the junction side of the die, that is, the side incorporating the active circuitry of the integrated circuit. As in the conventional IC described in connection with FIGS. 1 and 2, the active circuitry is contained within an area 60 having a boundary 62 . The area 60 , in accordance with the specific example under consideration, has a square or rectangular configuration bounded by four lines 62 a - 62 d paralleling respective ones of the peripheral edges 58 a - 58 d of the die 52 . The boundary lines 62 b - 62 d substantially coincide with the edges 58 b - 58 d , respectively.
[0033] The active circuit area 60 , including its dimensions and circuit contents, is conventional and the same as already described. Thus, high power dissipation active circuit elements, represented by a block 63 , are disposed along one the boundary line 62 a paralleling the peripheral edge 58 a of the die 52 .
[0034] In accordance with the invention, the portion of the die between the boundary line 62 a and the edge 58 a comprises a heat spreading extension 64 of inactive semiconductor substrate material. The extension 64 extends along the entire length of the boundary line 62 a and has a width, w, which may measure 1 mm by way of example and not limitation, for an IC die 0.76 mm thick and having an active circuit area 60 measuring 22×22 mm. The extension 64 serves during operation of the integrated circuit package 50 to establish a thermal energy flow path to spread and conduct heat away from the active circuit area 60 and to transfer that heat to the cover 40 via a heat transfer interface 66 for dissipation to the ambient environment. A similar heat transfer interface 68 couples the underside of the die and the upper surface 16 of the package substrate 14 .
[0035] As before, the heat transfer interface 66 comprises a compliant, conductive epoxy such as a silver filled epoxy, while the interface 68 comprises a compliant, non-conductive epoxy. The thermal interfaces 66 and 68 above and below the IC die extend across the entire upper and lower major surfaces 54 and 56 of the integrated circuit die 52 including the heat-spreading extension 64 formed thereon. As shown in the enlargement of FIG. 6, heat, represented by the arrows 70 , is thus transferred from the active circuit area 60 into the extension 64 and from there through the heat transfer interface 66 to the cover 40 of the device package.
[0036] The extension 64 is created during the manufacture of the die in the wafer form. During the wafer sawing operation, the wafer is cut in such a manner that an inactive margin of semiconductor remains adjacent to the high power circuit boundary 62 a to form the extension 64 .
[0037] In some cases this approach might increase the cost of the integrated circuit by reducing the number of dies that can be placed on a single wafer. However, any increased cost is outweighed by the device cooling made available through the present invention which reduces or may even eliminate the need for any of the cooling enhancements mentioned earlier.
[0038] As will be evident to those skilled in the art, the cooling benefits afforded by the present invention will vary with the design and power distribution of the semiconductor device. FIG. 8 is a graph showing the cooling effect imparted by an extension of inactive semiconductor material for a 0.76 mm thick VLSI CPU of a specific design and a specific power distribution across an active circuit area having a high temperature region adjoining one of the boundaries. It will be seen that for the specific example that is the subject of FIG. 8, the addition of an extension of even a modest width, w, of, for example, 1 mm to 1.5 mm by itself significantly decreases the maximum junction temperature.
[0039] [0039]FIG. 8 shows that for a given die thickness, the cooling benefit obtained diminishes as the width of the extension increases. Also, it will be evident that the increased amount of heat spreading provided by the extension is a function of both the die thickness and the width of the extension. Thus, as another example, a die having a thickness of 0.38 mm would benefit substantially from an extension having a width of only 0.4 to 0.5 mm.
[0040] [0040]FIGS. 9 and 10 show alternative, preferred embodiments of the invention. FIG. 9 depicts a die 80 having extensions 82 and 84 of inactive semiconductor material projecting from two adjacent boundaries 86 and 88 of an active circuit area 90 , as well as from the corner 92 shared by those boundaries. FIG. 10 shows a square die 100 having four extensions 102 - 105 provided around an entire active circuit area 106 , including the corners thereof. The addition of extensions about the entire boundary of an active circuit area may be especially advantageous for small, high power semiconductor devices such as high power transistors and laser diodes that are individually packaged. Additional extension configurations will suggest themselves to those skilled in the art depending upon the heat transfer requirements of a particular device.
[0041] It will be evident to those skilled in the art that instead of forming the die extension(s) from inactive semiconductor material that is completely inactive, low power dissipation circuit elements could be carried by the extension. Significant heat spreading benefits could thereby still be obtained. | The overall thermal resistance of a semiconductor device package containing a semiconductor die such as a VLSI IC die is reduced so as to improve the thermal performance of the package without any modification of the basic package structure. An extension of inactive or substantially inactive semiconductor material is added to the die adjacent to the boundary of a heat dissipating active circuit area on the die thereby increasing the effective heat transfer area of the die and establishing a heat spreading flow path to conduct heat away from the active circuit area. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of bandpass sampling using single sideband conversion, and more particularly, to a method of bandpass sampling using single sideband conversion which is capable of improving an efficiency of bandpass sampling by performing a bandpass sampling after converting a double-sideband RF signal to a single-sideband signal in the bandpass sampling process which down-converts the RF signal to a baseband in the frequency domain, which is obtained by removing either upper-sideband or lower-sideband spectrum from a double-sideband spectrum of an RF signal.
2. Description of the Related Art
With current mixture of various wireless communication schemes, researches for a terminal structure which can accommodate multi standards have been in progress. Among other things, a software defined radio (SDR) technique which can reconfigure the entire function of a wireless communication system by reconfiguration of software based on a highly advanced digital signal processing technique. Such SDR can allow to accommodate multiple wireless communication standards in an integrated fashion as a single transmission/receipt system platform by only changing appropriate software modules. Such an SDR technique is standing out as a core terminal technique covering the forthcoming wireless techniques.
An RF hardware platform like in the SDR technique that is designed to handle multiple RF standards together requires a processing capability over a wideband frequency band. However, development and module implementation of the related RF devices having such a wideband frequency characteristic needs to be developed further to satisfy the actual practicability in technical and economical terms. Accordingly, the methods of converting and processing wideband RF signals using advanced signal processing techniques have emerged recently, one of which is the software-based bandpass sampling scheme which down-converts an RF signal into a baseband signal.
A bandpass sampling scheme is a method of shifting a frequency of a modulated bandpass signal by sub-sampling the modulated signal, thereby allowing a lower sampling frequency to be utilized.
FIG. 1 shows an example process of frequency down-conversion of one RF signal in a conventional bandpass sampling technique.
As shown in the figure, a signal input through a wideband antenna 10 is amplified by a wideband low noise amplifier (LNA) 11 and then a signal having a desired RF band is extracted from the amplified signal by bandpass filter 12 . An analog-digital converter (ADC) 13 converts an analog signal into a digital signal which is then processed by a subsequent digital signal processor (DSP) 14 for restoration of the originally-transmitted signal.
In addition to the conversion of the analog signal into the digital signal, the ADC 13 performs a frequency down-conversion for converting the RF band signal into a signal at a low frequency band close to DC through the bandpass sampling. This allows a RF bandpass signal to be converted into a baseband signal using a sampling frequency lower than one which can be obtained according to a Nyquist sampling theorem. Accordingly, conventional complicated RF signal processing parts which were used for frequency down-conversion of RF signals can be omitted and a sampling frequency required for ADC can be lowered, thereby a processing burden of a digital processor and a cost can be reduced.
An RF signal consists of an upper sideband spectrum and a lower sideband spectrum, both of which in fact contain the same information. Since the sampling frequency of the bandpass sampling used in frequency down-converting of an RF signal is lower than the Nyquist sampling frequency, a very careful exercise in the sampling should be performed so that the wanted RF signal spectrum is shifted to the predetermined low-frequency baseband while completely avoiding overlapping with any other spectrum that could also be shifted by down-converting bandpass sampling. In particular, if multiple RF signals are to be frequency down-converted simultaneously through one bandpass sampling process, there is much higher possibility of spectrum overlapping with one another in the down-converted baseband. Accordingly, a more strict bandpass sampling process is required for the frequency down-conversion process.
Since a higher sampling frequency is required for bandpass sampling of multiple RF signals, there is a need of a more efficient bandpass sampling method which is capable of lowering the bandpass sampling frequency leading to a reduced burden to ADC performance as well as a reduced processing load to the subsequent signal processing processes.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a bandpass sampling method using a single sideband conversion, which is capable of alleviating a frequency overlap problem in down-conversion and lowering a high sampling frequency in conventional bandpass sampling methods in order to increase a signal processing efficiency by converting multiple RF bandpass signals into signals having a single sideband spectrum obtained by removing either upper or lower sideband spectrum of the RF bandpass signals before sampling the multiple RF bandpass signals.
It is another object of the present invention to provide a bandpass sampling method using a single sideband conversion, which is capable of alleviating a burden of a digital signal processing for wideband signals by transforming multiple RF bandpass signals into single sideband signals using a Hilbert transformer before being bandpass sampled, and performing a bandpass sampling process of converting the single sideband signals into baseband signals simultaneously.
It is still another object of the present invention to provide a bandpass sampling method using a single sideband conversion, which is capable of easily obtaining a low sampling frequency for multiple RF bandpass signals by converting the multiple RF bandpass signals into single sideband signals, obtaining effective sampling frequency domains by combining two of the converted single sideband signals, obtaining a common effective sampling frequency domain, and determining the minimum sampling frequency in the common effective sampling frequency domain.
To achieve the above-mentioned objects, according to an aspect of the invention, there is provided a bandpass sampling method of an analog RF signal receiving system which receives an analog RF signal and converts the analog RF signal into a digital signal by bandpass sampling with a single sideband signal conversion, including: a bandpass filtering step of selecting one or more analog RF signal of a desired frequency band; a converting step of converting the bandpass filtered signals into complex signals which contain only a single-sideband spectrum by removing either negative or a positive frequency components in the frequency domain; and a bandpass sampling step of bandpass sampling the complex signals with a lower sampling frequency that can down-convert RF bandpass signals to baseband signal.
Preferably, the bandpass sampling step includes a step of selecting the minimum frequency of a common region of the obtained one or more effective sampling frequency domains as a sampling frequency and performing bandpass sampling with the selected sampling frequency.
Preferably, the bandpass sampling step includes a step of configuring the filtered signal obtained in the bandpass filtering step as an I channel signal and configuring the complex signals obtained in the converting step as a Q channel signal to form a complex single sideband signal I(t)+jQ(t) with no spectrum in a negative frequency domain.
Preferably, the bandpass filtering step includes a step of using a plurality of bandpass filters to filter a desired frequency band of the one or more analog RF signal.
Preferably, the sampling step includes: a step of configuring all combinations of two signals from the two or more complex single sideband signals; a step of obtaining effective sampling frequency domains for the configured signal combinations and obtaining a common effective sampling frequency domain which is common to the obtained effective sampling frequency domains; and a step of selecting the minimum frequency in the obtained common effective sampling frequency domain as a sampling frequency.
ADVANTAGES OF THE INVENTION
According to one aspect of the invention, the bandpass sampling method using a single sideband conversion provides an advantage of alleviating a frequency overlap problem in down-conversion and lowering a high sampling frequency by converting multiple RF bandpass signals into signals having a single sideband spectrum obtained by removing either upper or lower sideband spectrum of the RF bandpass signals before sampling the multiple RF bandpass signals, which results in lowering the required ADC performance and hence decrease in costs for ADC design and related parts, and processing for various kinds of signals at a lower digital data rate.
According to another aspect of the invention, the bandpass sampling method using a single sideband conversion provides an advantage of alleviating a burden of a digital signal processing for wideband signals with an additional simple configuration by transforming multiple RF bandpass signals into single sideband signals using a Hilbert transformer before being bandpass sampled, and performing a bandpass sampling process of converting the single sideband signals into baseband signals simultaneously.
According to still another aspect of the invention, the bandpass sampling method using a single sideband conversion provides an advantage of easily obtaining a low sampling frequency for multiple RF bandpass signals by converting the multiple RF bandpass signals into single sideband signals, obtaining effective sampling frequency domains for combinations of two single sideband signals, obtaining a common effective sampling frequency domain, and determining the minimum sampling frequency in the common effective sampling frequency domain.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 shows a conventional example bandpass sampling system structure which down-converts a single RF signal;
FIG. 2 shows a bandpass sampling system configuration according to an embodiment of the present invention;
FIG. 3 shows a bandpass sampling system configuration for multiple RF signals according to an embodiment of the present invention;
FIG. 4 shows an example spectrum distribution in a frequency domain of N RF signals;
FIG. 5 shows a spectrum distribution with only positive frequency domain components as a result of single sideband conversion for the signals shown in FIG. 4 ;
FIG. 6 shows a spectrum distribution of two RF band signals;
FIG. 7 shows an example frequency down-converted signal spectrum distribution obtained when two RF signals of FIG. 6 are subjected to bandpass sampling;
FIG. 8 shows a spectrum distribution of three RF signals; and
FIG. 9 is a flow chart showing a bandpass sampling process according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter, preferred embodiments of the present invention will be described in detail with the accompanying drawings.
FIG. 2 shows a structure of a system which performs bandpass sampling for one RF signal after being converted into a single sideband signal. An RF signal input through a wideband antenna 21 is amplified by a wideband low noise amplifier (LNA) 22 and then only a signal having a desired RF band is extracted from the amplified signal and signals having different RF bands are removed from the amplified signal by a bandpass filter 23 . In FIG. 2 , the bandpass filtered signal is separated into two signals, one being directly applied to an ADC 26 to form an I(t) channel signal and the other being applied to an ADC 25 through a Hilbert transformer 24 to form a Q(t) channel signal. After the Q(t) channel signal is made to be a complex signal, the I(t) channel signal and the complex Q(t) channel signal are summed to give a final complex signal I(t)+jQ(t).
The complex signal I(t)+jQ(t) becomes an analytic signal having no spectrum in a negative frequency domain. The complex Q(t) channel signal may be expressed as follows.
Q
(
t
)
=
I
(
t
)
*
1
π
t
[
Equation
1
]
Where, a symbol * represents a convolution operation, which means that an impulse response function of the Hilbert transformer 24 is 1/πt.
In other words, the signal Hilbert-transformed by the Hilbert transformer 24 has a complex function and is summed with the non-Hilbert-transformed signal to form a single sideband signal (I(t)+jQ(t)). The Hilbert transformer 24 and the ADC 25 and 26 may be implemented by hardware separately from a DSP 27 or, in some cases, may be integrated with the DSP 27 . When a software configuration is more widened in the future, even the shown bandpass filter 23 could be implemented by software.
FIG. 3 shows a bandpass sampling system configuration for frequency down-converting N RF signals simultaneously. This configuration for frequency down-converting N RF signals simultaneously employs N different carrier frequencies allocated according to different communication standards and N bandpass filters 30 fitting to bandwidths of signal carried on the respective carrier frequencies. The remaining configurations are similar to those shown in FIG. 2 .
That is, even in the case of the configuration for frequency down-converting N RF signals simultaneously, an additional component to the basic configuration is only the Hilbert transformer 24 , giving insignificant increase in the entire hardware configuration. The related cost increase could be low as compared to the advantages caused by the lowered sampling frequency in frequency down-conversion, which will be described later.
FIG. 4 shows an example spectrum distribution where N signal are arranged on N carrier frequencies in a frequency domain. More specifically, FIG. 4 shows a typical form of multiple RF signals where N bandpassed signal X k (f) (k=1, 2, . . . , N) are arranged on respective different carrier frequencies f ck (k=1, 2, . . . , N) in a non-overlapping manner). At this time, the signal arrangement a symmetrical form 41 and 42 in a double sideband.
FIG. 5 shows a spectrum distribution 41 without components 42 of a negative frequency domain component, which is obtained when the I(t) channel signal and the Q(t) channel signal formed by the inserted Hilbert transformer 24 in FIG. 3 are summed in the DSP 27 . This embodiment addresses a method of achieving bandpass sampling by sub-sampling a signal whose spectrum exists in only one negative or positive frequency domain with the other negative or positive frequency domain removed as shown in FIG. 5 .
FIG. 6 shows parameters set to represent an RF spectrum signal for the purpose of deriving a process of obtaining an effective sampling region. In this figure, two signal spectrums 50 and 51 separated from each other are used for the purpose of simplicity of description.
X m (f) 50 represents a spectrum of a signal X m (t) and X n (f) 51 represents a spectrum of a signal X n (t). f Lm and f Um represent a lower limit frequency and an upper limit frequency of the signal X m (t), respectively. f Ln and f Un represent a lower limit frequency and an upper limit frequency of the signal X n (t), respectively. BW m (=f Um −f Lm ) represents a bandwidth of the signal X m (t) and BW n (=f Un −f Ln ) represents a bandwidth of the signal X n (t). A parameter fs related to the bandpass sampling represents a sampling frequency. Here, the upper limit frequency f Uk =f Ck +(BW k /2) and the lower limit frequency f Lk =f Ck −(BW k /2).
FIG. 7 shows an example spectrum distribution where two spectrum signals which are frequency down-converted by the bandpass sampling in FIG. 5 do not overlap with each other. To this end, an effective sampling frequency has to satisfy the following two constraints. First, as a constraint on an upper value of a sampling frequency, f Ln,r (A) of a signal 61 obtained by left shifting X n (f) 51 to (r m,n ) th by the bandpass sampling has to be larger than f Um of X m (f) 50 of a different RF signal. Second, as a constraint on a lower value of a sampling frequency, f Un,r+1 (B) of a signal 62 obtained by left shifting X n (f) 51 of an RF signal to (r m,n +1) th has to be smaller than f Um of the RF signal X m (f) 50 . These two constraints may be expressed by the following equations, respectively.
f
C
n
-
BW
n
2
-
r
m
,
n
f
S
≥
f
C
m
+
BW
m
2
[
Equation
2
]
f
C
n
+
BW
n
2
-
(
r
m
,
n
+
1
)
f
S
≤
f
C
m
-
BW
m
2
[
Equation
3
]
The above two equations may be added to give the following equation.
f
C
n
-
m
+
(
BW
m
+
n
/
2
)
r
m
,
n
+
1
≤
f
S
m
,
n
≤
f
C
n
-
m
-
(
BW
m
+
n
/
2
)
r
m
,
n
[
Equation
4
]
Where, f Cn−m =f Cn −f Cm , BW m+n =BW m +BW n , and r m,n is an integer which is defined by the following range.
0
≤
r
m
,
n
≤
⌊
f
C
n
-
m
-
(
BW
m
+
n
/
2
)
BW
m
+
n
⌋
[
Equation
5
]
An effective sampling frequency range for bandpass sampling of the two RF spectrum signals X m (f) and X n (f) can be obtained from Equation 4. That is, since the minimum sampling frequency corresponds to the largest value of the parameter in the denominator of the left term of Equation 4, Equation 4 may be arranged as follows.
f
S
m
,
n
_
min
=
f
C
n
-
m
+
(
BW
m
+
n
/
2
)
⌊
f
C
n
-
m
-
(
BW
m
+
n
/
2
)
BW
m
+
n
⌋
+
1
[
Equation
6
]
FIG. 8 shows a spectrum distribution of three bandpass RF signals. A method of obtaining an effective sampling region required in a process of frequency down-converting the three RF signals simultaneously will be described below. When signals 70 and 75 in negative and positive frequency domains as shown in FIG. 8 are passed through the configuration described with reference to FIG. 3 , signals in only one of the negative and positive frequency domains are left. When combinations of two among such three RF signal components are set and Equation 3 is applied thereto, it is possible to obtain effective sampling frequency range for two signal components, i.e., a sampling frequency range f S1,2 for X 1 (f) 71 and X 2 (f) 72 , a sampling frequency range f S1,2 for X 1 (f) 71 and X 3 (f) 73 , and a sampling frequency range f S2,3 for X 2 (f) 72 and X 2 (f) 73 . A frequency range corresponding to a common overlapping portion of the three frequency regions obtained thus is an effective sampling frequency range. This may be expressed by the following equation.
f S,three =f S 1,2 ∩f S 1,3 ∩f S 2,3 [Equation 7]
Where, a symbol ∩ represents an intersection which means a common portion of two domains. In addition, the minimum value which can be obtained within the effective sampling frequency range obtained in the above process is the minimum sampling frequency which may be expressed by the following equation.
f S,three,min =min{ f S,three } [Equation 8]
The above process may be expanded to N RF signals for generalization. A generalized effective sampling frequency range for N RF signals can be expressed by the following equation.
f
S
,
all
=
f
S
_
1
⋂
f
S
_
2
⋂
f
S
_
3
⋂
…
⋂
f
S
_
N
-
1
In
this
equation
,
f
S
_
1
=
f
S
1
,
2
⋂
f
S
1
,
3
⋂
f
S
1
,
4
⋂
…
⋂
f
S
1
,
N
f
S
_
2
=
f
S
2
,
3
⋂
f
S
2
,
4
⋂
f
S
2
,
5
⋂
…
⋂
f
S
2
,
N
f
S
_
3
=
f
S
3
,
4
⋂
f
S
3
,
5
⋂
f
S
3
,
6
⋂
…
⋂
f
S
3
,
N
⋮
f
S
_
N
-
1
=
f
S
N
-
1
,
N
[
Equation
9
]
In other words, when sampling frequency ranges for all combinable pairs of two RF signals of N spectrum signals are obtained using Equation 4 and then a common overlapping portion of these sampling frequency ranges is obtained as shown in FIG. 9 , this portion is just an effective sampling frequency domain for N signals. In this case, the minimum value, i.e., f S,min =min{f S,all }, in the effective sampling frequency range is the minimum sampling frequency.
FIG. 9 is a flow chart showing a process of determining the above-mentioned minimum sampling frequency. As shown, RF signals passed through a wideband antenna and a low noise amplifier are bandpass-filtered into N RF signals through N bandpass filters (S 10 ).
The filtered N RF signals are directly provided to one ADC to form an I channel signal, and at the same time, are transformed into a complex signal using a Hilbert transformer (or a corresponding different kind of transformer or its variant) and then provided to another ADC to form a Q channel signal, both of which are summed to form a single sideband signal I(t)+jQ(t) (S 20 ).
All combinations of two of N signals in the single sideband with an overlap permitted are obtained (S 30 ).
Effective sampling frequency ranges are calculated for the obtained combinations using Equation 4 (S 40 ).
A common effective sampling frequency range is calculated from the effective sampling frequency ranges for the obtained combinations (S 50 ).
The smallest frequency in the obtained common effective sampling frequency range is determined to be the minimum sampling frequency (S 60 ).
The above-described embodiments addressed the configuration and a method which are capable of significantly lowering a sampling frequency using a bandpass sampling technique, required for a software defined radio (SDR) system and the like. This can be employed for most cases where N wireless communication standards are simultaneously received by one radio device and are down-converted into baseband signals to extract a desired signal.
Even if a sampling frequency even lower than a Nyquist sampling rate is selected when N signals are simultaneously down-converted, the use of the above-described embodiments enables a signal processing at an intermediate frequency (IF) stage without any aliasing which is a distortion due to signal overlapping. In addition, since the complex bandpass sampling scheme of the embodiments of the present invention can obtain a wider and more flexible effective sampling region and even lower minimum sampling rate than those in conventional real number bandpass sampling schemes, which results in lowering of required ADC performance and hence decrease in costs, and data processing at a lower digital data rate and hence reduction of signal processing burden and provision of a margin for a variety of signal processing.
While the present invention has been particularly shown and described with reference to exemplary 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 spirit and scope of the present invention. The exemplary embodiments are provided for the purpose of illustrating the invention, not in a limitative sense. 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. | The present invention provides a method of bandpass sampling which particularly includes the single-sideband signal conversion procedure prior to the sampling process in the purpose of lowering the required sampling frequency. Conversion of the bandpass RF signal into a single-sideband spectrum signal which has the spectrum components only in either the positive or the negative frequency domain is accomplished by bandpass-filtering, or more effectively by using a Hilbert transformer. This invention includes a method of finding the minimum sampling frequency for simultaneous frequency down-conversion of multiple RF bandpass signals. It is expected from this invention that the components additionally required in the RF receiver due to the proposed bandpass sampling method is the bandpass filters or the Hilbert transformer for single-sideband conversion, but the benefits from this invention could be the reduced ADC speed performance and the subsequent digital processing load in the receiver system because of the reduced data rates. | 7 |
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to an apparatus for explosively severing tubular members and more specifically to an apparatus for severing tubular members below a body of waer, such as, for example, an offshore rig platform pile.
During offshore drilling and production operations, it is sometimes necessary to move a platform to a different location, retrieving as much of the equipment as possible. An offshore platform is usually supported by a number of piles which extend from the platform downwardly through the body of water and below a mudline. It is usually there, below the mudline, that the piles have to be severed in order to the platform to be transported to a new, preselected location.
At present, the most commonly used explosive severing method utilizes a bulk explosive which is delivered to a level below the mudline through the interior of the pile, where it is detonated to produce an explosive charge. The results of such explosion are extremely unsatisfactory, since the unfocused charge not only creates signficant shock waves which create hazardous conditions for sea life, but the bottom of the so severed pile becomes flared, which makes it difficult for operators to remove the severed portion through the jacket which surrounds the pile circumferentially.
The currently used bulk explosive methods utilize approximately 60 lbs. of explosive or 1 lb. per diametric inch of the pile plus 10% or 15% of additional explosive.
Other devices and methods utilized to severe piles below the mudline include the use of a 2 point explosive, wherein a circular body carries a pair of diametrically positioned explosive units for detonating them at a point where the severing of the pile is desired.
The use of such an explosive also creates problems, one of the problems being a noncomplete severance of the pile or significant shock waves, which consequently effects the sealife.
There are also a number of methods which utilize ring-shaped explosive charges wherein the detonation is initiated at one point of the circle, allowing the detonation to spread out through the circle in a sporadic manner.
None of the above-noted devices can be utilized to create a focused charge which will accomplish severing of the pipe in the beneficial manner afforded by the present invention. It is therefore an object of the present invention to provide an apparatus wherein detonation is accomplished to create a focused charge, so that the pile or a tubular member is severed at an exact chosen location, without creating flare to the pile or unnecessary excessive shock waves affecting the sealife.
It is a further object of the present invention to provide an apparatus for creating a focused, uniform explosion for severing tubular objects wherein the detonation occurs at a plurality of points substantially simultaneously adjacent to the inner periphery of the tubular member being severed.
SUMMARY OF THE INVENTION
This and other objects which will be apparent to those skilled in the art are achieved by the present invention and the problems of the prior art are solved in a simple and straight-forward manner. The apparatus for severing tubular members comprises a frame with a pair of spaced-apart circular deflection plates held in parallel relationship to each other by a plurality of bolts, the apparatus also comprising a sleeve portion having a smaller diameter than the deflection plates and positioned perpendicularly to the deflection plates. A ring-shaped explosive is wrapped around the sleeve, on the outside thereof, with a plurality of detonating points equidistantly, circumferentially positioned in electrical communication with the detonation charge control means.
A pair of compression plates are attached in parallel to the deflection plates to insure a stable position of the deflection plates in relation to the explosive during detonation.
A stabilizing positioning assembly is attached to the bottom compression plate to insure proper alignment of the apparatus when it is being lowered into the pile. A central conduit passing through the top compression and deflection plates serves to house an electrical cable or transfer explosive for delivering an initiation means to the explosive for detonating it at a plurality of detonation points, thus insuring a substantially simultaneous detonation of the explosive around the inner periphery of the charge.
A second embodiment provides for the use of a ring shaped explosive "sandwiched" between a pair of deflection plates, with the radially extending explosive conduit communicating with the central conduit for delivering the electrical current or transfer explosive substantially simultaneously throughout the inner periphery of the explosive charge. A plurality of centralizers are mounted on the bottom and upper compression plates to allow for aligned lowering and positioning of the severing apparatus into the pile to a predetermined location below the mudline.
Other objects and purposes of the invention will be clear from the following detailed description of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational side view of the first embodiment of the apparatus in accordance with the present invention.
FIG. 2 is a cross-sectional view of the embodiment shown in FIG. 1.
FIG. 3 is a bottom view of the embodiment shown in FIGS. 1 and 2.
FIG. 4 is a top view of the embodiment shown in FIGS. 1-3.
FIG. 5 is an elevational view of a second embodiment of the present invention.
FIG. 6 is a top view of the apparatus of FIG. 5.
FIG. 7 is a cross-sectional view of the apparatus shown in FIGS. 5 and 6.
FIG. 8 is a schematic view of an offshore platform showing the water level and mudline into which piles of a platform are embedded.
FIG. 9 is a schematic view of an interior of a platform pile, with the apparatus of the present invention lowered to the level, wherein a severing of a tubular member is to take place.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference is now being made to FIGS. 1-4 which illustrate the first embodiment of the apparatus of the present invention. In this embodiment, the apparatus of the present invention is designated by numeral 10. The severing apparatus comprises a frame, comprised of a top compression plate 12, a parallel bottom compression plate 14, each being attached in parallel relationship to its corresponding deflection plate 16 and 18, respectively, through the use of spacer bars 20 fixedly attached substantially equidistantly at the peripheral edges of plates 12, 16 and 14, 18. The deflection plates 16, 18 and compression plates 12, 14 are circular in shape, having substantially identical diameters with the distances between the upper compression plate 12 and upper deflection plate 16 being substantially equal to the distance between the lower deflection plate 18 and the lower compression plate 14. The compression plate 12, spaced from the deflection plate 16 through the use of spacer elements 20 form the top portion of the apparatus, while the lower deflection plate 18 and the lower compression plate 14 spaced apart with the help of spacer elements 20 form the middle portion of the apparatus of the present invention. The top portion and the middle portion are secured in a fixed, spaced relationship through the use of securing bolts 22 equidistantly spaced about a circumference of a diameter smaller than the total diameter of the plates 12, 14, 16 or 18.
An annular sleeve 24 is positioned between the outer periphery of the deflection plates 16 and 18 and securing bolts 22, so that an annular space is provided between the sleeve 24 and the outer edges 26 and 28 of the deflection plate 16 and 18. The sleeve 24 is affixed perpendicularly to the deflection plates 16 and 18, in parallel to the securing bolts 22. A plastic explosive (not shown) is subsequently wrapped around the sleeve 24, on the exterior thereof, in the annular space 25 between the sleeve 24 and the outer edges 26 and 28 of deflection plates 16 and 18.
A central conduit 30 houses an electrical cable 32 which is connected in the usual manner, herein not shown, to an electrical detonation control unit positioned on the surface. Electrical current delivered through the cable 32 is supplied to a plurality of equidistantly spaced points throughout the circumference of the explosive wrapped about the sleeve 24, so that when the charge is detonated at the surface, the explosion will take place substantially simultaneously throughout the circumference of the explosive charge.
The bottom portion of apparatus 10 is designated by numeral 40 in the drawings and has a generally conical shape, with the apex 44 of the cone facing downwardly, and with the base of the cone being formed by a bottom surface of the compression plate 14. The conical portion 40 is formed by a plurality of elongated bars 42 radiating from the apex 44 of the conical portion 40 and extending to the periphery of the compression plate 14.
The conical portion 44 allows an easy alignment of the apparatus 10 when it is being lowered into the opening of a platform pile and adds structural support to the middle portion of the apparatus. The apparatus can be suspended through the use of conventional suspension means (not shown) attached to a pair of pad-eyes 46 and 48 affixed to the top surface of compression plate 12.
It should be noted that the diameter of the plates 12, 14, 16 and 18 could be varied in accordance with the diameter of the pile to be severed, the only requirement being that the diameter of the plates 12, 14, 16 and 18 be at least slightly smaller than the diameter of the central opening within the pile. Likewise, the diameter of the sleeve 24 can be varied depending on the amount of explosive to be utilizied at a particular cutting job, so that greater or less annular space 25 is left between the edges 26, 28 of the deflection plates 16 and 18 to the exterior of the sleeve 24.
Reference will now be made to the embodiment shown in Figs. 5-7, wherein numeral 50 designates the second emboidment of the apparatus in accordance with the present invention. Similar to the embodiment shown in FIGS. 1-4, the explosive cutting device 50 comprises a frame having a pair of parallel compression plates 52 and 54 connected to each other by a plurality of spaced-apart, peripherally mounted securing bolts 56 which extend through correspondingly aligned openings made in the compression plates 52 and 54. A pair of parallel deflection plates 58 and 60 are mounted between the compression plates 52 and 54 in parallel relationship thereto, so that the bolts 56 extend through the plates 58 and 60 through similarly co-aligned openings. The deflection plates 58 and 60 have a slightly smaller diameter than that of compression plates 52, 54. An explosive charge 62 is "sandwiched" between complementary mating surfaces of the deflection plates 58 and 60, first in explosive transfer channel 64.
The explosive transfer channel 64 is formed by complementary lower surface of the upper deflection plate 58 and upper surface of the lower deflection plate 60. The explosive transfer channel 64 is created by a plurality of spacers 65 which are filled in grooves in the lower surface of the upper deflection plate 58 and the upper surface of the lower deflection plate 60. The explosive transfer channel 64 communicates with an annular space 63 formed at the peripheries of the deflection plates 58 and 60, so that the main explosive charge 66 annularly encompasses the periphery of the deflection plates 58 and 60. To prevent the explosive charge 66 from releasing from the confines of the channel 64, a holding member 68 is provided adjacent the outer edges of the plates 58 and 60. The holding member 68 is attached perpendicularly to the deflection plates 58 and 60, closing the annular space 63 on the exterior thereof.
A central conduit 70 serves to house an electrical cable, or detonating cord or other suitable initiating means 72 which is designed to deliver detonating signal to the explosive charge 62. An explosive transfer channel 64 facilitates delivery of the detonating signal to a plurality of radially equidistantly spaced locations within the explosive charge 62, so that one detonating signal delivered to the center of the circular explosive charge, will create a "rippling" effect delivering detonating signal to a plurality of locations of the main explosive charge 66, thus causing a substantially simultaneous explosion within the apparatus 50, so that a focused charge is created to sever the tubular member substantially about its circumference as required.
A plurality of spring centralizing means 74 are securedly attached about the periphery of the top compression plate 52, extending upwardly therefrom and to the bottom compression plate 54, extending downwardly therefrom. The spring stabilizing means 74 can be attached for example, by bolts or by welding to the compression plates 52 and 54, the stabilizing means being in the form of C-shaped metal bands curved inwardly, in the direction to the center of the compression plates 52 and 54. The stabilizing means 74 assist in positioning and securing position of the apparatus 50 within a tubular member to be severed.
It is designed that the curved portion of the spring centralizing means 74 contacts the interior of the tubular member to be severed, so that the curved portion is in frictional engagement with the interior of the tubular member, preventing misalignment of the apparatus 50 within the tubular member. The spring centrailizing means 74 can be compressed, moving the metal bands inwardly, when the curved portion of the C-shaped stabilizing means contacts the interior of the tubular member, thus facilitating positioning the apparatus 50 at the designated level.
FIG. 8 schematically illustrates an offshore structure 78, with the water level designated by numeral 80 in the drawing.
As can be seen in the drawing, piles 82 extend below the mudline 84 within the surrounding jackets 86.
As schematically shown in FIG. 9, an apparatus 10 is lowered into the pile to approximately 20' below the mudline 84, it is designed for the pile to be severed. A detonation signal is sent from the surface in a conventional manner in order to initiate the explosion.
Many modifications and variations of the present invention will be come apparent to those skilled in the art in the light of the above teachings. It is therefore intended that the scope of the present invention be limited only by the scope of the appended claims. | The invention relates to an apparatus for explosively severing tubular members at a pre-designated severance level. The apparatus is designed to deliver a detonation signal to a ring-shaped explosive charge, to an annularly formed detonation signal receiving locations, so that explosion takes place substantially simultaneously about the circumference of the explosive charge about internal periphery of the tubular member at the severance level. | 4 |
[0001] Proteins have a strong affinity for the surfaces with which they come in contact. In pharmaceutical packages and medical devices this affinity often results in the loss of valuable proteins due to surface adsorption. Surface adsorption is governed by many factors including the nature of a protein, the character of the surface and the additives in the protein solution. Pharmaceutical packagers frequently overfill a container to account for protein loss due to absorption. Many attempts have been made to provide surfaces that resist protein adsorption. No one product can meet the needs of all protein solutions and package performance is highly unpredictable partly because the amount of protein absorption is dependent upon so many factors such as, for example, the pH of the solution, the surface coating and the nature and concentration of the protein. In the past, each new pharmaceutical solution was tested against specific packages or devices and the amount of protein left in the solution was measured to determine the protein loss due to absorption.
[0002] Proteins are a heterogeneous class of biomolecules with widely varying physico-chemical characteristics. Some general observations regarding the strength of interaction between proteins and surfaces can be made.
[0000]
TABLE I
Ideal characteristics of surfaces resistant to protein adsorption/denaturation
Desirable Surface
Characteristic
Rationale
Non-Ionic
A non-ionic surface is electrostatically neutral and will not attract or
ionically bind to proteins, which contain both positively and negatively
charged motifs.
Sterically
A surface containing, e.g., flexible polymeric dendrites provides a flexible,
hindering
protective barrier at the glass suface and precludes intimate glass/protein
contact, thus preventing adhesion and denaturation.
Hydrophilic
A hydrophilic surface promotes the formation of a compact H 2 O-rich layer
(Stern layer) at the surface of the substrates, e.g., glass which prevents
the more hydroscopic proteins in solution from coming into direct contact
with the, e.g., glass substrate.
Hydrogen bond
A hydrogen bond accepting surface will form hydrogen bonds with H 2 O
accepting
molecules found within the Stern layer, which will further prevent proteins
from interacting directly with the substrate.
[0003] A problem with current pharmaceutical packaging products or medical devices is that no one product possesses each of the positive traits that are needed to provide comprehensive, protein-deterring characteristics. This “mixed bag” of desirable/undesirable characteristics (Table II) renders the performance of products highly unpredictable for universal, protein-based pharmaceutical packaging applications. This unpredictability is evident when considering the highly contradictory results from various “protein adsorption” or “protein loss” studies, which date back to at least 1998. This unpredictability and lack of knowledge about how to truly prevent protein adsorption/loss is ultimately manifested in the inability of the pharmaceutical packaging or medical device industries to develop a single low-loss, protein inhibiting packaging product or device for the pharmaceutical or medical device industry.
[0000]
TABLE II
Assessing surface characteristics
Desirable
Type I/Type I-Plus
Siliconized
Characteristic
Glass
Glass/Plastic
TopPac Plastic
Non-Ionic
High negative surface
relatively
relatively non-ionic
charge at neutral pH
non-ionic
that promotes
interaction with
proteins
Sterically
No steric hindrance
Steric hindrance
No steric hindrance
hindering surface
characteristics
possible from
characteristics
characteristics
silicone chains
Hydrophilic
Cleaned glass
Silicone oils are
TopPac is an aliphatic,
surfaces are
generally highly
aromatic co-block polymer
hydrophilic
hydrophobic
and thus hydrophobic
Hydrogen bond
A glass surface will
Poor hydrogen
Poor hydrogen bonding
accepting
accept hydrogen
bonding
characteristics
bonding
characteristics
Type I is a product line of Schott-forma vitrum made from borosilicate glass with the highest class of hydrolytic resistance; Type I Plus is product line of Schott-forma vitrum with glass receptacles with a silicon oxide coating; TopPac is a product line of Schott-forma vitrum with polymer receptacles made of cyclic olefin copolymer like Topas (marked by Ticona)
[0004] The contradictory and sometimes confusing results from previous “protein loss” and “protein adsorption” studies have been further compounded by differences in the testing procedures and assays utilized for assaying “loss” and/or “adsorption”. In previous testing, variability in the testing parameters, including duration of the study, concentration of the protein, testing temperature, pH, use of detergents/additives, etc. have rendered final interpretation and comparison of results difficult or impossible. Further, most “protein loss” assays were conducted using techniques, such as the Bicinchoninic acid (BCA) technique which only allows for the determination of the protein concentration after an adsorption process, but provides no insight into where the proteins were preferentially adsorbed within the pharmaceutical package.
[0005] The assay of the present invention will enable drug formulators, medical device developers and pharmaceutical packaging developers to optimize formulations and material surfaces to inhibit the irreversible adsorption of drug compound while utilizing small quantities of compound containing solutions (<<1 ml) and small amounts of potential pharmaceutical packaging or device materials (surface areas <1 mm 2 ). Further, such testing can be achieved in a multiplexed manner (i.e., 2 to 10,000's of formulation/well surface combinations can be assessed on a single, chip-based platform) as shown in FIG. 1 . Further, such testing can be combined with more thorough testing in actual full scale pharmaceutical packages to fully characterize the performance and stability of a drug compound, e.g., with respect to an identified surface candidate, as shown in FIG. 4 , thus providing a total solution for pharmaceutical packaging or medical device optimization.
[0006] The assay enables a pharmaceutical packager to simultaneously directly compare the adsorption behavior of a specific protein (e.g., recombinant drug, cytokine, enzyme etc.) in a solution containing various specific additives (e.g., buffers etc.) under various specific conditions (e.g., pH, temperature etc.) against a variety of potential substrate surface coatings (e.g., silica, polymer coated glass etc.). The multiplexed assay enables the packagers to simultaneously target the specific packaging conditions (e.g., surface coating, pH, additives) that will result in the least amount of protein adsorption and thus product loss.
[0007] Generally, the present invention relates to a multiplexed assay that allows simultaneous measurement of the adsorption interaction of one or more protein solutions with one or more substrate surfaces. Briefly, a substrate is divided into multiple wells, each of which has a surface to be tested, e.g., the substrate surface per se or one which is coated or treated in some fashion. Each well of the multiple well substrates is then subjected to, i.e., exposed to a protein solution and the level of protein adsorption in each of said wells is determined. (The term “adsorption” is not intended to place any limitation on the nature of the interaction between the assayed component of a solution and the test surface. As long as the interaction is sufficient to keep the component in association with the surface sufficiently to be detected in an assay, it is included within the scope of the term.)
[0008] Preferably, the substrate is a glass slide or microtiter plate. Each substrate may contain from 2 to greater than 10,000 wells that are created, e.g., with a hydrophobic patterning material. Preferably, the substrate contains greater than 4 wells per substrate. More preferably, the substrate contains greater then 8 wells per substrate. Most preferably, the substrate contains greater then 16 wells per substrate. The protein solutions may contain buffers, salts, stabilizers, preservatives, acids and/or bases, etc., as are common in the pharmaceutical industry. Typically, the protein to be tested is an antibody, an enzyme, recombinant erythropoietin, a recombinant hormone, polypeptides in general, peptides, vaccines, etc. The level of protein adsorption in each of said wells may be determined by, for example, incubating the wells with labeled antibodies and scanning to determine the amount of protein bound. Alternatively, the level of protein adsorption in each of said wells may be determined by, for example, interrogation with an enzyme conjugated antibody and measuring the signal amplification. Thus, the amount of protein that adsorbs to the substrate surfaces under various conditions and various solution parameters can be easily determined.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0009] Various features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
[0010] FIG. 1 shows an image of a partitioned microscope slide format (left) and microtiter plate format (right). Such formats can be designed to contain from about 2 to >1000 individual wells.
[0011] FIG. 2 shows a pictorial representation that demonstrates how treated well surfaces can interact with drug compounds immersed in solution.
[0012] FIG. 3 depicts the steps involved in a typical assay. First (top left) a silicone-based superstructure is applied to the patterned substrate. Second (top right); solutions containing the protein drug compound(s) are added. Third (bottom left), a sealing strip is applied to the top of the device to inhibit evaporation. Finally (bottom, right), after washing and labeling, the amount of adsorbed protein is quantified via fluorescent scanning.
[0013] FIG. 4 shows a pictorial representation of one possible total pharmaceutical packaging development process, whereby multiplexed assays are first used to screen for optimal packaging conditions, and later followed by packaging-specific tests to achieve a final formulation.
[0014] FIG. 5 is a pictorial representation showing how different techniques could be used in conjunction to quickly and efficiently provide packaging/formulation solutions to the pharmaceutical industry.
[0015] FIG. 6 depicts a variety of contemplated patterning designs for use in the assaying applications of the present invention.
[0016] FIG. 7 depicts direct and indirect assay methods developed to determine protein adsorption to surfaces.
[0017] FIG. 8 shows the effect of different pHs on the ionic attraction of IgG to glass surfaces.
[0018] FIG. 9 shows the adsorption of different proteins to glass. Five proteins are used: IgG (G), Insulin (I), Histone (H), Fibrinogen (F), C. Anhydrase (C). They are incubated at 10 μg/ml at 3 different pHs ( 5 , 7 and 9 ).
[0019] FIG. 10 shows the effect of positively charged surfaces on the binding of positive and negative charged proteins.
[0020] FIG. 11 depicts the optimization of protein formulations on incubated glass slide wells with a protein in different buffers (A) and with and without Tween 20 (B).
[0021] Surfaces susceptible to protein adsorption include pharmaceutical packaging components (e.g., glass vials, ampoules, stoppers, caps, ready to fill syringes—glass and plastic, cartridge-based syringes, pure silica-surfaced vials, plastic-coated glass vials, plastic and glass storage bottles, pouches, pumps, sprayers and pharmaceutical containers of all types) and medical devices (e.g., catheters, stents, implants, syringes etc). Any candidate surface which is considered for contact with a protein and is susceptible to protein adsorption can be assayed.
[0022] Typically, the assay substrate material is glass or plastic. Preferably the substrate material is a SiO 2 based glass slide. Most preferably the glass comprises a commercially relevant glass which is used in pharmaceutical packaging applications such as, for example, one comprising 65-85 wt % SiO 2 , 3-20 wt % B 2 O 3 , 0-20 wt % Al 2 O 3 , 1-15 wt % Na 2 O, 1-15 wt % K 2 O, 0-10 wt % MgO, 0-10 wt % CaO and 0-10 wt % BaO.
[0023] A variety of known commercially available patterning compositions such as PTFE polymer (Poly Tetra Flourine Ethylene), fluoropolymers or silicone can be applied to the substrate to create hydrophobic boundary regions thereby creating wells. The boundary regions (i.e., walls) provide a barrier between each well surface (bottom, typically) where assaying reactions can be conducted. FIG. 6 depicts numerous well patterns that would be useful in the assay and methods of the present invention. The pattern design itself is flexible, being limited only to the human imagination and the limitations of graphics programs used to make symmetrical or unsymmetrical geometric patterns (repeating or non-repeating over the substrate surface) that include ovals, squares, rectangles, stars, etc. that can be adapted to the experimental assaying design as needed. The wells may or may not be interconnected to provide a means for interaction between two or more wells on a substrate. The patterning of the substrate into wells allows processing of multiple assays in parallel rather than serially. Patterned substrates, such as those disclosed in U.S. Ser. No. 10/778,332 titled “Low-Fluorescent, Chemically Durable Hydrophobic Patterned Substrates for the Attachment of Biomolecules,” ensure physical separation between the various relevant protein solutions being tested without the worry of cross contamination between assays. The patterning material is deposited by methods known in the art. Preferably the patterning material is screen-printed onto a glass substrate to provide distinct boundary and well regions.
[0024] It is contemplated that wells of the patterned substrate can in one embodiment remain uncoated and untreated, with just the underlying substrate composition exposed to the various protein solutions. When the well area has not been additionally coated or treated, then the substrate surface for that well will be an untreated substrate surface. Alternatively, each well can be treated or coated with a different test coating or surface treatment. It is also contemplated that each well can be treated or coated with the same substrate treatment or coating or multiplexed treatments and/or coatings. Or some of the wells may be treated and others may be coated. Obviously a large variety of combinations of well coatings and/or treatments can be tested on a single substrate.
[0025] Substrate surfaces comprise uncoated, coated, treated or untreated well surface areas such as, for example:
[0000] 1) Glass (e.g., silicates, borates, borosilicates, phosphates, etc);
2) Glass that has been heat-treated with an oxy-fuel flame to emulate the processing utilized to convert glass tubing into pharmaceutical packaging;
3) Polymeric materials, such as acrylics, polycarbonates, polyesters, polypropylenes, polyacetals, polystyrenes, polyamides, polyacrylamides, polyimides, polyolefins, cyclic olefin copolymers, especially bicyclic olefin copolymers, or polymeric films;
4) Organic coatings having the following functional group(s) present at the well surface: amine, epoxide, isocyanate, isothiocyanate, acyl azide, N-hydroxysuccinimide (NHS) ester, sulfo-NHS ester, sulfonyl chloride, imidoester, carbodiimide, acid anhydride, iodoacetyl, malemide, aziridine, acryloyl, disulfide, diazoacetate, aryl azide, thiol (sulfhydryl), mercapto, acetate, hydroxyl, carbonate, aldehyde, alkane, alkene, carboxylate, esters, ethers, etc.—(this is a non-exhaustive list of potential functional groups); organic coatings/films composed of dendrimers, polymers (polyethylene glycols—PEG), nanoparticles, and hyper-branched polymers, e.g., that contain the aforementioned functional groups;
5) Metallic coatings such as gold, silver, platinum, palladium, etc; and/or
6) Inorganic oxide coatings such as SiO 2 , TiO 2 , ZrO 2 , Al 2 O 3 , etc.
[0026] Many other possibilities exist, e.g., other surfaces used in the pharmaceutical packaging and medical device fields.
[0027] Other typical surface treatments or coatings include polymer coated surfaces, native glass, etched glass, thermal treated glass, borosilicate glass coated with a PEG layer, Hyal, siliconized glass or plastic, TopPac, Type 1, Type 1 plus. It is contemplated that any pharmaceutical packaging or medical device surface, surface treatment or coating can be tested against the various parameters of protein solutions. There is a wealth of general knowledge regarding surfaces and or coatings that resist protein adsorption. See, for example, Emanuele Ostuni, Lin Yan, George M. Whitesides— Colloids and Surfaces Biointerfaces 1999, 15, 3-30. Additionally, there is a wealth of general knowledge regarding surfaces that are designed to decrease protein adsorption. See, for example, Emanuele Ostuni, Robert G. Chapman, R. Erik Holmin, Shuichi Takayama, George M. Whitesides— Langmuir 2001, 17, 5605-5620. A large variety of surface coating combinations can exist on a single substrate. All of these represent the large number of available surface treatment and/or coating possibilities.
[0028] As used herein, the term “protein solution” refers to a particular protein of interest in the presence of (typically) an aqueous solution that may contain various additives. Typical protein solutions to be tested include pharmaceutically relevant moieties such as cells, tissues, and derivatives thereof. Among the proteins are included any polyaminoacid chain, peptides, protein fragments and different types of proteins (e.g., structural, membrane, enzymes, antigens, monoclonal antibodies; polyclonal antibodies, ligands, receptors) produced naturally or recombinantly, as well as the derivatives of these compounds, etc. Specific protein drugs include antibodies (e.g. Remicade and ReoPro from Centocor; Herceptin from Genentech; Mylotarg from Wyeth, Synagis from MedImmune), enzymes (e.g. Pulmozyme from Genentech; Cerezyme from Genzyme), recombinant hormones (e.g., Protropin from Genentech, Novolin from Zymogenetics, Humulin from Lilly), recombinant interferon (e.g., Actimmune from InterMune Pharmaceutical; Avonex from Biogenldec, Betaseron from Chiron; Infergen from Amgen; Intron A from Schering-Plough; Roferon from Hoffman-La Roche), recombinant blood clotting cascade factors (e.g., TNKase from Genentech; Retavase from Centocor; Refacto from Genetics Institute; Kogenate from Bayer) and recombinant erythropoietin (e.g., Epogen from Amgen; Procrit from J&J), and vaccines (e.g., Engerix-B from GSK; Recombivax HB from Merck & Co.).
[0029] Typically drug compounds to be tested will be immersed within an aqueous solution that may contain various additives. Such additives have an influence on the binding of a protein drug to a packaging or device surface. Typical additives include buffers (e.g., phosphate, Tween, citrate, and/or acetate), salts such as sodium chloride at physiological concentrations, stabilizers (e.g., anti-oxidants such as histadine, chelators such as EDTA, human albumin or glycerin etc.), preservatives (e.g., phenol, metacresol, benzyl alcohol etc.), and acid or bases (e.g., citric acid, sodium hydroxide, hydrochloric acid, acetic acid etc) to adjust the pH of the formulation to physiologically safe levels.
[0030] The patterned and treated substrate can be used to simultaneously investigate the interaction between multiple relevant protein solution parameters (duration, temperature, concentration, pH, etc.) and a variety of surface coatings/treatments using very small amounts of protein. After the assay is completed, the amount of protein adsorbed on each well of the patterned substrate can be detected using known commercially available detection methods for protein adsorption.
[0031] The most common analytical techniques for determining protein adsorption take advantage of the change in optical and/or electrical properties of a surface that has adsorbed proteins. These techniques provide a measurement of the presence/absence of species on a surface. Some techniques allow determination of additional information as to the amount or thickness of adsorbed protein (SPR; ellipsometry; QCM; XPS; radioactive isotopic labeling; solute depletion; fluorescence emission spectroscopy), conformation (ATR FT-IR; Raman scattering; XPS; low angle X-ray reflectivity; scanning force microscopy), or binding energy to the surface (scanning force microscopy). Surface plasmon resonance (SPR) is very sensitive to changes in the index of refraction at and near the surfaces of metal films. SPR can measure the before/during/after protein adsorption to determine kinetic and thermodynamic information regarding the adsorption of proteins. See, for example, Jennifer M. Brockman, Anthony G. Frutos, Robert M. Corn— J. Am. Chem. Soc. 1999, 121, 8044-8051. Ellipsometry can be used to determine if proteins have adsorbed to a surface by measuring the change in the index of refraction before/after protein adsorption to give an experimental thickness of the layer of proteins adsorbed. This detection method is useful if a substrate has a refractive index different from the coating. See, for example, Delana A. Nivens, David W. Conrad— Langmuir 2002, 18, 499-504; M. Mrksich, L. E. Dike, J. Tien, D. E. Ingber, G. M. Whitesides— Exp. Cell Res. 1997, 235, 305-313; and Kevin L. Prime, George M. Whitesides— J. Am. Chem. Soc. 1993, 115, 10714-10721. Quartz crystal microbalance (QCM) measures changes in the fundamental frequency of vibration for a quartz crystal for protein adsorption via the piezoelectric effect, yielding adsorbed protein layer thickness. Surface acoustic wave (SAW) and acoustic plate mode (APM) devices takes advantage of changes in surface acoustic waves (velocity and amplitude) when proteins adsorb to the surface of a crystal modified with electrodes, detecting the presence or absence of protein binding. See, for example, Robert Ros Seigel, Philipp Harder, Reiner Dahint, Michael Grunze, Fabien Josse— Anal. Chem. 1997, 69, 3321-3328). X-ray photoelectron spectroscopy (XPS) uses X-rays to eject electrons from atoms; each atom has different XPS spectrum and allows determination of the number and type of atoms per unit area. XPS can also be used to determine if protein has adsorbed to a surface by measuring the spectrum from a protein adsorbed to a surface vs a non-protein adsorbed surface. Attenuated total internal reflectance fourier transfer infrared (ATR FT-IR) spectroscopy examines the twisting, bending, rotating, and vibrational motions of molecules. The spectra provide information that can be used to determine the presence or absence of a protein and give information regarding its conformation on the surface. Low-angle X-ray reflectometry may be used to determine the variations in electron density at an interface and allows resolution of packing differences in layers. Radioactive isotope labeling can be used to quantify the amount of protein adsorbed by ionization detection (Geiger counter) or liquid scintillation. See, for example, Y. S. Lin, V. Hlady and J. Janatova— Biomaterials, 13, (1992), p. 497. Solute depletion measures the amount of protein in solution before or after exposure to a surface. Scanning force microscopy uses a probe tip with a known position to characterize a surface species. The probe tip may be coated with specific molecules to determine chemical and physical interactions with a surface. See, for example, J. N. Lin, B. Drake, A. S. Lea, P. K. Hansma, and J. D. Andrade— Langmuir, 6, (1990), p. 509. Fluorescence emission spectroscopy measures the inherent fluorescence of a molecule or the fluorescence of a fluorescent label on a molecule. Proteins may be fluorescently labeled and detected using fluorimeters. See, for example, V. Hlady, Applied Spectroscopy 1991, 45, 246 and D. J. Sbrich and R. E. Imhof in Topics in Fluorescence Spectroscopy , J. R. Lakowicz Ed., Plenum, New York, (1991), p. 1. Circular dichroism measures the magnitude of polarized light rotation and detects the presence or absence of proteins. See, for example, C. R. McMillin and A. G. Walton— J. Colloid Interface Sci., 84, (1974), p. 345. Raman scattering is complimentary to infrared and measures the vibrational spectrum of molecules that undergo change in polarizability. It is used to determine the presence or absence of specific molecules/functional groups. See, for example, T. M. Cotton in Surface and Interfacial Aspects of Biomedical Polymers, 2, J. D. Andrade Ed., Plenum Press, New York, (1985), p. 161. In general, this invention is not limited in any way by the nature of the forces holding the protein molecules to the substrates.
[0032] Fluorescent detection can be utilized as a direct indication as to the amount of a protein bound to a surface. In this method the protein to be studied is conjugated to a fluorescent dye, such as those typically used in DNA and protein microarrays (e.g., Cy-dyes from GE Healthcare, Alexa-flour dyes from Molecular Probes, or other dyes available commercially and used typically to label proteins (dansy/amide, flouresceine)). These dyes are normally conjugated to the protein through amine-reactive groups (typically, NHS-esters, aldehydes or epoxides) and can be easily detected. The quantitative amount of labeled antibody can be measured after washing via laser scanning, utilizing any one of the various commercial scanners from Axon, Perkin Elmer, Alpha Innotech, Tecan, Agilent, Affymetrix, etc. utilized for microarray analysis (as shown pictorially in FIG. 3 ). This method is easy to apply to many different proteins, with the major caveat being that the protein is modified, which in some instances may lead to interactions with the surface that may not occur in the unmodified protein. It will also change the charge distribution on the protein since the reactions mostly involve the epsilon-amino group of lysine as well as the amino terminal. An alternative method involves detecting the adsorbed proteins with a labeled antibody. This indirect method involves obtaining specific antibodies to a protein and labeling them with the same fluorophores described above.
[0033] If desired, the multiplexed assay of the present invention can be used in conjunction with other protein loss/adsorption assays such as those described in Table III. Once the multiplexed assay has identified desirable formulation and surface combinations, the following assays can be used to test protein loss within a full scale pharmaceutical package or medical device.
[0000]
TABLE III
Techniques identified for assessing protein loss/adsorption
TECHNIQUE
DESCRIPTION
PROS
CONS
Multiplexed
Fluorescent-labeled
High throughput,
Useful for
Utilize this test for rapid
assay
proteins are deposited
low cost,
primary
investigation of multiple
into the wells of a flat
extremely low
screening, as
protein-adsorption
substrate, incubated
protein amounts
testing is not
mechanisms.
and protein adsorption
required, direct
conducted within
is measured by
assay.
a true pharma
fluorescent scanning.
package.
BCA test
Staining technique
Simple, fast,
Does not allow
Utilize in conjunction
based on Cu 2+
accurate
one to
with the Amino Acid
reduction to Cu + in the
technique, which
determine where
Assay described below
presence of proteins.
is highly
the proteins
when conducting tests
Test is performed on
accepted in the
were “lost”
within actual full scale
protein-containing
industry.
within the
pharmaceutical
solutions after being
pharma
packages.
tested within
package.
pharmaceutical
packaging.
Amino Acid
Assay for remnant
Accurate and
Not amenable to
Utilize this technique in
Assay
protein adsorbed within
accepted assay
high throughput
conjunction with the
the package by
can be used to
screening.
BCA test when
hydrolyzing proteins
detect what
conducting testing
and measuring for
amount of
within actual full scale
amino acid
protein was lost
pharmaceutical
concentration using
within a package
packages.
column
and determine
chromatography.
where the
majority of
protein adhesion
occurred.
[0034] The techniques described above can be used in the approach pictorially described in FIG. 5 to accelerate testing and to provide packaging support and therefore solutions to the pharmaceutical and medical device industries.
[0035] Thus, the assay of the present invention is useful in allowing packaging and medical device scientists to study the stability of novel new drug compounds such as, for example, small molecules, antibodies, proteins (natural or recombinant), cytokines, vaccines, under a multitude of different packaging and formulation conditions, while consuming very limited amounts of a precious drug compound. Tens of thousands of formulation/well surface combinations can be assessed on a single, chip-based platform. Thus, one can rapidly identify the optimal combination of material surface and product formulation for a given protein-based pharmaceutical compound. The ability to tailor the surface properties of materials and optimize formulations will reduce or eliminate loss of valuable protein due to surface adsorption and allow easy scale-up from assay into a tangible, scalable prototype or a commercial batch.
[0036] Although this application is written primarily in terms of proteins, polypeptides or peptides, it can also be applied to other biomolecules such as nucleic acids, polynucleotides (e.g., DNA, RNA, mRNA, pDNA, etc., oligonucleotides), protein/nucleic acid complexes, etc. by straightforward extension application of the invention to biomolecules is routine. Application of this invention to biomolecules is routine. Assay methods and techniques (reagents, signaling methodology, detection methodology, etc.) are all well known.
[0037] By “biological specificity” is meant the normal type of biological lock and key type of bonding which is sufficiently unique to identify a species from all others, e.g., antibody-antigen (protein) interactions, receptor-ligand interactions, highly stringent hybridization, etc. Instead, the surface differences here are designed not to identify proteins but to vary adsorption of a protein entity to a treated surface.
[0038] Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.
[0039] The entire disclosure[s] of all applications cited herein are incorporated by reference herein.
EXAMPLE I
Multiplexed Formulation Optimization Protocol
[0040] a) Choose a substrate which is ideally in the general shape of a microscope slide (nominally 25×75×1 mm 3 ) or a microtiter plate (substrate within the MTP frame has nominal dimensions of 74×110×1 mm 3 ).
[0041] b) Partition off the substrate into individual wells (of any shape) with cross sections that can range from <100 μm to several mm. These wells may be formed by, for example, screen-printing a hydrophobic pattern onto the starting substrate, as described in patent application U.S. Ser. No. 10/778,332 titled “Low Fluorescent, Chemically Durable Patterned Substrates for the Attachment of Biomolecules.” The resulting patterned substrate can take on the general appearance shown by the examples in FIG. 1 .
[0042] c) Interrogate each individual well ( FIG. 1 ) with various drug compounds as shown in FIG. 2 . The drug-compound-containing solution may be placed into each well via milliliter, microliter or nanoliter pipeting.
[0043] d) Allow solutions to interact with the well surfaces from a time ranging from 1 sec to 12 months or longer, based on the intent of the study; (e.g., some aging studies may require interaction times of >1 year). During aging, a sealed superstructure can be utilized to inhibit evaporation, as shown in FIG. 3 . If desired, the polymeric-based superstructure can be applied before the aqueous solution is deposited into the wells, followed by the application of a sealing strip that eliminates the risk of evaporation.
[0044] e) Characterize or measure the amount of drug compound that has irreversibly adsorbed to the well surfaces. This can be done by various methods described above, such as, for example:
i) After the protein has been allowed to adsorb, the wells may be incubated with labeled antibodies, washed, and then scanned to determine the amount of protein bound; or ii) After the protein has been allowed to adsorb, the wells may be interrogated with enzyme conjugate antibodies, so as to allow for signal amplification similar to an ELISA assay; or iii) Different types of probes can be used to detect the adsorbed proteins including antibodies (mono- and polyclonal), affibodies, antibody fragments, oligonucleotides, amine reactive fluorophores and dyes (e.g. Cy-dyes and others as described above), specific ligands (e.g. detecting biotinylated proteins with fluor-labeled streptavidin), and small molecules that specifically bind to the protein of interest.
EXAMPLE II
[0048] Two types of assays demonstrate the adsorption of proteins in solution to glass surfaces. The use of glass slides divided into wells with a silicone superstructure allows incubation of 100 μL volumes of protein solution. To detect and quantify the protein bound to the surface fluorescent dyes are used to ensure adequate sensitivity. Two types of assays, a direct and an indirect assay are discussed.
[0049] The direct assay is based on protein solutions, where the protein is modified to contain Cyanine dye (Cy3) (see FIG. 7A ). The protein solution is incubated in the slides wells and then removed. The excess protein:dye conjugate is washed with water for injection (WFI); the slide is dried and then scanned using a 532 nm laser scanner. The amount of fluorescent signal is measured throughout the well and the amount of protein is calculated using calibration curves.
[0050] In the indirect assay (see FIG. 7B ), unlabelled protein is incubated in the wells. After the incubation period the protein solution is removed and the wells are washed with WFI. A fluorescent dye that contains an NHS-ester is incubated in the well. The dye NHS-ester reacts with the amine groups on the protein and the fluorescent moiety becomes attached to the proteins adsorbed to the surface. The excess unreacted dye is then washed from the well, the well is dried and the slide is scanned as above. The quantification of the protein bound is also done by calibration curves for each specific protein.
EXAMPLE III
[0051] A multiplexed assay is used to assess the adsorption of a protein formulated at different pHs. Proteins have an isoelectric point (pI), which is the pH at which the net charge of the protein is zero. At any pH below the pI the protein will be positively charged, while at pH above the pI the net charge will be negative. Meanwhile the zeta potential for glass is negative at any pH above 3, therefore the glass will be negatively charged above that pH.
[0052] Human IgG labeled with Cy3 fluorescent dye (Excitation 532 nm, emission: 535 nm) in a 100 mM Phosphate buffer at pH 5, 6, 7, 8, and 9 is formulated. The pI of IgG is 7.8, therefore at most pH's the protein would be positively charged. 100 μL of the protein solution is incubated in wells formed on slides as described for a period of 72 hours. After incubation the slide wells are washed with 100 μL of water for injection (WFI) three times. The slides are then scanned in a laser scanner.
[0053] The images shown in FIG. 8 show the adsorption of the IgG solutions on two types of glass. It can be observed that as the pH increases the amount of IgG-Cy3 adsorbed to the surface decreases due to the increase in negative charge that repels the protein from the negatively charged glass surface. The optimal formulation in this case should be done at pH of around 9 to minimize de binding due to ionic interactions.
EXAMPLE IV
[0054] Given the different nature of proteins in general it is to be expected that different proteins will adsorb to a varying degree to the same surface. In this example the adsorption of different proteins all formulated in the same solutions is tested.
[0055] Different aspects of protein characteristics in the proteins selected including large (Fibrinogen, molecular weight 340,000) to small (insulin, molecular weight 5600), acidic pI (albumin, pI 5.2) to basic pI (histone, pI 11.5) are covered. All are formulated in a 100 mM phosphate buffer at pH 5, 7, and 9, and incubated as described in the previous example.
[0056] The results shown in FIG. 9 show that highly basic proteins (histone) and large proteins (fibrinogen) tend to adsorb the most. This makes sense considering the ionic attraction between the large amount of positive charges from histone, and the size of fibrinogen which allows for the simultaneous interaction of many residues of the protein at once.
EXAMPLE V
[0057] The effect of the surface charge will also modify the adsorption of the proteins. As the negative charges on glass tend to attract positively charged proteins. Positively charged surfaces should tend to repel them and attract negatively charged proteins. Applying an aminosilane coating to the surface of the slides tests this theory. The coating results in a surface of packed amino groups that are protonated. The surface is then incubated with both basic (histone) and acidic (albumin) proteins. As can be seen in FIG. 10 the positively charged proteins adsorb less onto the positive surface, while the negatively charged proteins adsorb more when compared to a non-coated control.
EXAMPLE VI
[0058] The optimization of the formulation of a protein therapeutic can consider many types of buffers at different pH and concentrations. The methods described within are aimed at increasing the throughput with which these variables are tested.
[0059] Protein solutions are made with different buffers and incubated in slide wells as describe in Example I. The proteins are then washed and the slides scanned. The results in FIG. 11A demonstrate the effect of the different buffer compositions and concentrations when compared to incubating the wells with protein solutions in WFI (water for injection). It can be clearly seen that some buffers can reduce the adsorption of proteins to the surface by as much as 60%.
[0060] In another case the same protein solution is compared in terms of adsorption with and without the presence of a surfactant typically used in the pharmaceutical industry (Tween-20). The results in FIG. 11B clearly show that the addition of the surfactant reduces the binding of the protein by at least 50%.
[0061] This example shows the utility of the methods in deterring protein adsorption, since just two multiplexed experiments can optimize the conditions to reduce the adsorption of the protein by a factor of 10.
[0062] In the foregoing and in the examples, all temperatures are set forth uncorrected in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.
[0063] The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.
[0064] From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. | A multiplexed assay method capable of measuring the interaction of one or more protein, polypeptide or peptide solutions with one or more substrate surfaces comprises contacting each of the wells of a multiwell substrate with the same or different protein solution, the surfaces of said wells being the same as that of said substrate or being substrate surface treated and/or coated to provide test surfaces, and determining the level of protein adsorption in each of said wells. | 1 |
FIELD OF THE INVENTION
[0001] The present invention is generally directed to catalytic combustion, and more specifically to a method and an apparatus for use therewith for the reformation of methane into partial oxidation products and the oxidation of those products at a temperature below the adiabatic temperature thereof.
BACKGROUND OF THE INVENTION
[0002] Methane is an abundant hydrocarbon that is used as a source of fuel in numerous applications, such as industrial radiant heaters, gas turbines, home furnaces and cooking equipment. While methane can be made available in a relatively pure form, it is more commonly provided as a constituent of natural gas, of which it is the primary component.
[0003] Natural gas is typically combusted in an open flame, a process referred to as diffusion burning, which generates certain pollutants. One particularly undesirable class of pollutants formed during diffusion burning is nitrous oxides, i.e. NOx. In diffusion burning, NOx can be formed by any one of three possible mechanisms: thermal, prompt, and fuel bound. The production of NOx by the thermal and the prompt mechanisms, however, far exceeds that produced from the fuel bound mechanism. Consequently, efforts to reduce NOx pollution focus on reducing NOx formation by the thermal and/or the prompt mechanisms.
[0004] NOx produced by the thermal mechanism, i.e. thermal NOx, is often the dominant mechanism. Thermal NOx is formed when the heat being released by diffusion burning is sufficient to provide the necessary energy for the nitrogen in the air to combine with the oxygen in the air. Generally, at flame temperatures below 1700 K, the production of thermal NOx is insignificant. However, as flame temperatures increase, the production of thermal NOx increases sharply.
[0005] Thermal NOx production can be controlled by regulating reactant stoichiometry. To burn a fuel it must be mixed with an oxidant. For example, to burn methane oxygen must be provided. The ratio of the fuel and oxidant, that is methane and oxygen, is the reactant's stoichiometry. Reactant stoichiometry is expressed in terms of a fuel/oxidant equivalence ratio, or where the oxidant is oxygen as a constituent of air—fuel/air ratio. The fuel/oxidant equivalence ratio is the ratio of the actual fuel/oxidant ratio to the stoichiometric fuel/oxidant ratio. For example in the case of methane (CH 4 ), the combustion reaction is CH 4 +2O 2 →CO 2 +2H 2 O. Therefore, a stoichiometric fuel/oxidant ratio is one part CH 4 and two parts O 2 . Thus, if a mixture had this ratio of CH 4 and O 2 , the reactant stoichiometry as expressed by the fuel/oxidant ratio of the mixture would be 1.0 (an actual mixture having these proportions would be referred to as stoichiometric).
[0006] A mixture having an equivalence ratio greater than 1.0 is fuel rich, i.e., in the case of the above methane reaction more than one part fuel for each two parts of oxygen, and a mixture having an equivalence ratio less than 1.0 is fuel lean, i.e. in the case of the above methane reaction less than one part fuel for each two parts of oxygen. When combustion is adiabatic, stoichiometric mixtures burn relatively hotter than non-stoichiometric mixtures and the further away the mixture is from stoichiometric the relatively cooler it burns.
[0007] NOx production by the prompt mechanism, i.e. prompt NOx, is a fuel-rich, gas-phase phenomenon. The reaction is quick and completes within the diffusion flame. The production of NOx by the prompt mechanism can only be controlled if the diffusion flame is eliminated, in whole or in part.
[0008] NOx formation from the combustion of methane could be greatly reduced if methane could be combusted at temperatures below 1700 degrees K and diffusion flame could be avoided. It is well known in the art that if methane is catalytically combusted, i.e. oxidized in the presence of a catalyst, the energy within the methane can be released without the formation, or limited formation, of thermal and/or prompt NOx.
[0009] A problem, however, with the catalytic combustion of methane is that methane is a very stable molecule. Thus, it is more difficult to oxidize than higher order hydrocarbons, such as propane. Methane can be catalytically combusted under fuel lean conditions producing combustion temperatures below 1700 degrees K. When a palladium-based catalyst is used the reaction may become unstable due to properties of Pd-PdO transformation of the catalyst. Hysteresis in the catalyst activity makes controlling the reaction extremely difficult. Platinum based catalysts on the other hand can provide more stable operation. However, volatility of Pt at the desired temperatures under lean conditions is very high. Thus, platinum catalyst lacks durability.
[0010] Based on the foregoing, it is an object of the present invention to develop a method and an apparatus for the combustion of methane that overcomes the problems and drawbacks associated with the prior art.
SUMMARY OF THE INVENTION
[0011] The present invention is directed in one aspect to a method for the combustion of methane. In the method, a fluid stream including fuel having methane and oxygen that is in fuel rich proportions, i.e. having a fuel/oxidant equivalence ratio greater than 1.0, is provided. The fluid stream flows into a reformation reactor having a catalyst therein that promotes the reformation of methane (CH 4 ) into carbon monoxide (CO) and hydrogen (H 2 ).
[0012] The catalyst reforms at least a portion of the methane in the fluid stream into carbon monoxide and hydrogen creating an exhaust stream exiting the reformation reactor having various fuel constituents therein, such as unreformed methane, CO and H 2 . The exhaust stream is then divided into a plurality of exhaust streamlets by passing the exhaust stream into a manifold having a plurality of discrete discharges. As a portion of the exhaust gas exits through a discharge, an exhaust streamlet is formed. Sufficient oxygen is then added to the exhaust streamlet such that the fuel constituents therein and the oxygen are in fuel-lean proportions. Same amount of oxygen should be added to each streamlet, such that variations in the equivalence ratios between the streamlets are small. The exhaust and second fluid are added together, not mixed. In the present invention, it is desired that the exhaust and the second fluid enter the porous media as distinct flow steams. It is understood however, that the two fluids will be in contact along an interface and that incidental diffusion of one fluid into another will occur. It is expected that if sufficient time is provided the diffusion combustion would occur at the interface before the two streamlets can mix. To avoid gas phase flame oxidation of the exhaust stream, which is undesirable in this invention, combined stream formed after adding the second stream to the exhaust stream should be passed into the porous media before combustion takes place. Finally, at least a portion of the CO, H 2 and CH 4 in the exhaust streamlets is oxidized by passing the combined stream through a porous media that absorbs and then radiates some of the heat generated by the oxidation.
[0013] A catalytic burner suitable for performing the above method includes a reformation reactor incorporating a catalyst. A manifold that receives the exhaust stream from the reformation reactor and passes the exhaust stream through a plurality of discharges forming part of the manifold thereby creating a plurality of exhaust streamlets. The exhaust streamlets then enter a flow path where the exhaust streamlets are directed into a proximally located porous media. Means for introducing a second fluid into the flow path are also provided.
[0014] The reformation reactor is a partial oxidation reactor. In a partial oxidation reactor, the catalyst and its associated geometry, e.g. substrate and dispersion thereon, defines an activity relative to the flow rate, i.e., residence time, of the methane/oxygen thereover such that when the catalyst and the methane/oxygen interact partial oxidation products and not complete oxidation products are predominantly formed. In the case of methane and oxygen, partial oxidation products are H 2 and CO, while the compete oxidation products are H 2 O and CO 2 . An example of a reformation reactor for methane suitable for this application is disclosed in U.S. Pat. No. 5,648,582, the disclosure of which is incorporated herein in its entirety.
[0015] As those skilled in the art will appreciate, the selectivity, i.e. the ability to produce one product in favor of another, in the reformation process can be manipulated by controlling the temperature of the fluid stream. In the case of a fluid stream including methane and oxygen in fuel rich proportions, preheating of the fluid stream increases the selectivity in the reformation of methane in favor of H 2 and CO versus CO 2 and H 2 O. Therefore, an enhancement to both the method and the catalytic burner incorporates heating the fuel stream prior to its entry into the reformation reactor.
[0016] The exhaust and the second fluid are mixing and reacting inside the porous media to further oxidize at least part of the exhaust stream to the complete oxidation products. The porous media absorbs some of the heat created by the exothermic oxidation reaction and emits it in the form of IR radiation, assuring that the temperature remains below the adiabatic flame temperature defined by the reactant stoichiometry of the fuel constituents and oxygen. A porous media can be any media through which a gas can flow, while continuously encountering solid surfaces. In other words, porous media is comprised of alternating regularly or randomly empty volumes and filled volumes. Empty volumes should form a continuous network, such that the porous media remains permeable to permit the flow of a fluid therethrough. The porous media should have a pore size, which describes the average size of the empty volume (if the pores size in not round the smaller dimension), that is generally uniform, but small deviations are acceptable. Porous media having a few large empty volumes and otherwise generally uniform smaller volumes could be problematic. The precise pore size, porosity (ratio of open volume to total volume) and material is application dependent.
[0017] The material for the porous media should be chosen to withstand the temperatures generated in the exothermic oxidation process and effectively emit heat in the form of infrared radiation (IR). Pore size and porosity are chosen large enough to minimize pressure drop induced by the porous media but small enough when compared to the total volume in which the oxidation reaction between the exhaust and the second stream takes place.
[0018] As those skilled in combustion will readily appreciate, the reformation reactor requires that the catalyst therein be at a certain temperature to perform the reformation. The catalyst can be brought to this temperature by any one or a combination of well know procedures, such as heating the fluid stream, or direct heating of the catalyst.
[0019] Regardless of the method chosen, the exhaust gas will have a temperature upon exiting the catalyst equal to the operational temperature chosen for the reformation reactor plus the exothermal resulting from the exothermic oxidation process taking place therein. It should be remembered that the proportions of fuel constituents to oxygen within the exhaust stream are still be quite rich, i.e., the initial stream had fuel rich proportions and oxidant was consumed along with fuel creating a progressively richer fuel stream as it passed through the reformation reactor. Therefore, although the fuel constituents in the exhaust gas will be quite hot, oxidation will not occur within the exhaust stream until additional oxidant is added.
[0020] Where the fuel/oxygen stoichiometry, flow rate and IR radiation are such that porous media is hot enough, oxidation of fuel inside the porous media will occur upon contact with an oxidant. Where the porous media is not hot enough to support oxidation on contact with an oxidant, the porous media can utilize a suitable oxidation catalyst to sustain the oxidation reaction. It is understood that a catalyst can be used even if the fuel constituents are hot enough to support combustion.
DESCRIPTION OF THE DRAWINGS
[0021] [0021]FIG. 1 is a side view of the catalytic burner of the present invention.
[0022] [0022]FIG. 2 is a top view of the manifold of the present invention taken along line 2 - 2 of FIG. 1.
[0023] [0023]FIG. 3. is a side view of a second embodiment of the catalytic burner of the present invention.
[0024] [0024]FIG. 4 is a top view of the catalytic burner taken along the line 4 - 4 of FIG. 3 showing the heat exchanger.
DETAILED DESCRIPTION
[0025] As shown in FIG. 1, the catalytic burner, generally referred to by the reference number 10 , is comprised of a reformation reactor 12 , a manifold 14 and a porous media 16 . An inlet stream 18 enters the reformation reactor 12 by means of a flow path 20 creating an exhaust stream 24 . The manifold 14 and reformation reactor 12 are connected by a flow path 26 such that the exhaust stream 24 enters the manifold 14 to exit through a plurality of discharges 28 (See FIG. 2). Exhaust streamlets 30 are formed by the discharges 28 . The discharges 28 are positioned proximate the porous media 16 , and connected by a flow path 32 , such that upon exiting the discharges 28 the exhaust streamlets 30 enter an inlet face 15 of the porous media 16 .
[0026] An oxidant 34 flows around the manifold 14 permitting the oxidant 34 to flow into the flow path 35 connecting the discharges 24 to the porous media 16 . As shown in FIG. 2, the discharges 28 are positioned to disperse uniformly the exhaust stream 24 as exhaust streamlets 30 over a dispersion area 36 , defined by a perimeter 38 . The hub and spoke design of the manifold 14 assists in distributing the exhaust streamlets 30 uniformly under the porous media 16 across the inlet face 15 , but the manifold 14 and discharges 28 therefrom could be of any design, such as port injectors positioned in the housing 12 , thus the invention should not be considered limited to the manifold 14 shown.
[0027] The flow path 32 and manifold 14 should cooperate to uniformly disperse the oxidant 34 and exhaust stream 24 across the inlet face 15 of the porous media 6 . It is a feature of this invention that the oxidant 34 and exhaust streamlets 30 be associated, but not mixed in the flow path 32 . Associated means that the exhaust streamlets 30 and oxidant 34 are brought in contact but are not provided sufficient time to inter-defuse, and therefore, the exhaust streamlets 30 and oxidant 34 generally enter the porous media 16 as discrete streams.
[0028] In the method of the present invention, the inlet stream 18 has methane and oxygen in fuel rich proportions. Preferably, the oxygen is provided as a constituent of air. If desired, the methane can be provided as a constituent of a blended fuel, such as natural gas. Preferably, the methane and oxygen are highly mixed. The operational perimeters of the reformation reactor 12 , including the catalyst therein, are selected such that some, or for all practical purposes all, of the methane is converted primarily into CO and H 2 instead of CO 2 and H 2 O. This creates an exhaust stream 24 from the reformation reactor 12 having therein at least the fuel constituents CO, and H 2 .
[0029] The fuel constituents in the exhaust stream 24 define an adiabatic temperature. The exhaust stream 24 is then divided into exhaust streamlets 30 . The exhaust streamlets 30 are then associated with additional oxygen, generally as a constituent of air, in fuel lean proportion (exhaust stream to oxygen). It is preferred that exhaust and oxygen are mixed in a proportion close to stoichiometric with small excess oxygen. The exhaust streamlets 30 and additional oxygen then pass into the porous media 16 where mixing and oxidation, which is exothermic, takes place. The porous media 16 is constructed of materials that absorb some of the heat of reaction, such that the oxidation occurring in the porous media 16 is below the adiabatic temperature of the fuel constituents. The heat of reaction absorbed by the porous media 16 is radiated therefrom in the form of infrared radiation.
[0030] As discussed above and shown in FIGS. 1 and 2, the catalytic burner 10 has a plurality of discharges 28 that divide the exhaust stream 24 into exhaust streamlets 30 . In the context of the method, the exhaust stream 24 , which is in fuel rich proportion, has associated with it a certain amount of energy. The energy density of the exhaust stream is proportional to the amount of fuel passing through a certain cross-sectional area per unit of time, i.e. to the volumetric flow rate of the exhaust stream 24 . U.S. Pat. No. 5,648,582 suggests that one essential feature of the reformation reactor 12 is that the inlet stream 18 enters the reactor at very high space velocity and the reformation reaction occurs at short residence time. This provides that flow space velocity and associated energy density in the exhaust stream 24 will also be high. If the exhaust stream 24 were to be exposed to additional oxidant as a single stream, excessive amount of heat, associated with the oxidation reaction, would be released in a small volume of the porous media 16 . This excessive heat could cause deterioration, or failure, of the porous media 16 . The manifold 14 distributes the exhaust stream 24 over the larger cross-sectional area, effectively decreasing the energy density in the stream. The energy density associated with individual exhaust streamlets 30 and any diffusion flame that maybe associated therewith is considerably lower and may be adjusted depending on the application. The discharges 28 can also act as diffusers to reduce further the power density, i.e., power per area, of the exhaust stream 24 .
[0031] [0031]FIG. 3 is a second embodiment of the catalytic burner which is similar to the previous embodiment, therefore, like reference number preceded by the number 1 are used to indicate like elements. In this embodiment, the catalytic burner 110 is positioned in an interior area 140 of a housing 142 . Also positioned within the interior area 140 is a heat exchanger 144 . The reformation reactor 112 is positioned within the porous media 116 as opposed to under it. In this embodiment, the inlet stream 118 enters a heat exchanger 144 positioned within the interior area 140 adjacent the porous media 116 . The porous media 116 has a catalyst 146 deposited on the surface thereof. The catalyst 146 is selected to support the continued oxidation of the H 2 , CO and CH 4 in the exhaust streamlets 130 . The inlet stream 118 flows through the heat exchanger 144 prior to entering the reformation reactor 112 .
[0032] As explained above, in the method of the present invention an oxidation reaction occurs in the porous media 116 . As such, some of the heat of reaction 147 leaves the porous media 116 and is conducted into contact with heat exchanger 144 , where some of the heat of reaction is transferred into the inlet stream 118 flowing therein. Referring to FIG. 4, the heat exchanger 144 is comprised of a tube 148 that has been formed into a flat coil about a center point on an axis designated by the letter A.
[0033] The heat exchanger 144 could be of any other design, which allows part of heat released in porous media 116 to be transferred into the inlet stream 118 , thus, the invention should not be considered limited to the heat exchanger 144 shown.
[0034] Continuing with FIG. 3, the manifold 114 is adapted to receive the exhaust stream 130 from the reformation reactor 112 . In this embodiment, the means for introducing additional oxidant 134 between the discharges 128 and the porous media 116 is by the introduction of additional oxidant 134 into the housing 142 below the discharges 128 . Depending upon the method of operation, the flow of additional oxidant 134 may be by natural convection or a pump, such as a fan. In most cases, the introduction point is not critical as oxygen as a constituent of air will be the oxidant 134 and the air will naturally flow to the desired location. Therefore, the means could include passages in the housing, or the additional oxidant 134 could flow from a point above the porous media 116 into the housing 142 .
[0035] In this embodiment, the reformation reactor 112 is shown positioned within the porous media 116 . This is not a requirement of the invention, as the reformation reactor 112 could be positioned anywhere including outside the interior area 40 .
[0036] In the method of the present invention, this embodiment is designed to provide the additional step of preheating of the inlet gas stream 118 using some of the heat of reaction produced by the exothermic reaction in the porous media 116 . Preheating the inlet stream 118 offers the advantage of increasing the selectively to CO and H 2 within the reformation reactor 12 . This is but one method of preheating, therefore the invention should not be considered so limited. Preheating of the inlet stream 118 by other means such as electric resistance are considered within the scope of the invention. Preheating of the inlet stream can assist in starting the catalytic burner.
[0037] The porous media 16 , 116 is a media through which a gas can flow. In the preferred embodiment, the porous media 16 , 116 was made from a plurality of stacked short-channel screens. The invention should not be considered so limited however, as other media could be used such as pellets, foams or gauzes and even a single screen. Generally, porous media are graded by “pore size.” Another important parameter for this invention, however, is consistency of pore size. The porous media 16 , 116 is designed to promote interaction of the fuel constituents within the exhaust stream 24 with the additional oxidant 34 , 134 , extract heat from the ongoing oxidation, and radiate infrared radiation. Further, the porous media 16 , 116 continually assures that the exhaust stream 24 , 124 and oxidant 34 , 134 are divided into small pockets. In other words, the exhaust stream 24 , 124 and oxidant 34 , 134 cannot reform into a large volume. These requirements mean that preferably the pores within the porous media 16 , 116 are generally uniform. Pore size is chosen such that the pores are large enough to minimize pressure drop but small enough to assure an acceptable heat release within a pore.
[0038] Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible, particularly versions having more than two catalysts. Therefore, the spirit and scope of the invention should not be limited to the description of the preferred versions contained herein. | The invention is a method and apparatus for use therewith for the combustion of methane. The method employs reformation of methane and oxygen in fuel-rich proportions into carbon monoxide and hydrogen and residual methane. The carbon monoxide, hydrogen and residual methane is then combined with oxidant in fuel lean proportions to continue oxidation in a porous media that absorbs some of the heat of oxidation and radiates the heat as infrared radiation. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to semiconductor memory devices, and more particularly to a high speed programmable read only memory (PROM) device.
2. Description of the Prior Art
Semiconductor programmable read only memories (PROMs) are well-known in the prior art. A PROM consist of an array of memory cells, each cell in which may be programmed to store a binary "0" or "1" (a so-called binary "bit") after the PROM has been completely fabricated and assembled. Once an individual cell is programmed, it may not later be changed or "reprogrammed".
One common method of constructing PROMs is to use a bipolar transistor as the programming means. Such a bipolar transistor is shown in cross-section in FIG. 1a. Transistor 9 includes collector 13 formed in the semiconductor substrate using an impurity of a first conductivity type, base 12 formed in the collector 13 using an impurity of a conductivity type opposite to that of collector 13, and emitter 11, formed in base 12 using an impurity the same conductivity type as, but of a higher concentration than in collector 13. In this fashion, either an NPN or a PNP transistor is formed. In order to program this type of cell to represent a first binary state such as a "1" or "0" (the unprogrammed cell represents the other state), sufficient emitter-collector current must be applied to form an electrical short (i.e., a low resistance path) between emitter 11 and collector 13 through base 12. This short is shown in FIG. 1b and is labeled 14. Typical emitter-collector currents required to form short 14 depend upon a number of factors (such as base doping concentration and base width) and are in the range of 70 to 150 milliamps. It is therefore generally recommended by manufacturers of such PROMs that a programming current on the order of 200 milliamps be used, in order to ensure that desired shorts are formed in selected cells, thereby programming these cells. Due to the high programming current required, access devices associated with the programming means of each cell must be capable of handling such currents without themselves being physically damaged. For this reason, bipolar transistors, which have high current carrying ability, are used as access devices in prior art PROM devices.
FIG. 2 shows a schematic diagram of a portion of a prior art PROM device utilizing bipolar transistors as the programming means. PROM device 100 contains bit lines B 1 and B 2 , and word lines W 1 and W 2 . The cell accessed by word line W 1 and bit line B 1 is labeled 11. The cell accessed by word line W 1 and bit line B 2 is labeled 12. Similarly, the cell accessed by word line W 2 and bit line B 1 is labeled 21, and the cell accessed by word line W 2 and bit line B 2 is labeled 22. Each cell is similarly constructed, and thus the following discussion of cell 11 applies equally to all cells in the memory array 100.
Memory cell 11 comprises access transistor T 11 having collector 1, base 2, and emitter 3. Collector 1 is connected to bit line B 1 , and base 2 is connected to word line W 1 . Emitter 3 is connected to collector 4 of programming transistor P 11 as shown. P 11 is the transistor which is to be programmed to reflect the state of the cell to which it is a party. Base 5 of programming transistor P 11 is floating, and emitter 6 is connected to bias line 91. Connected to bit line B 1 is sense amplifier A 1 having output terminal O 1 .
During the programming of memory cell 11, a short is created between collector 4 and emitter 6 of programming transistor P 11 in the following manner. Bias line 91 is connected to ground. All other bit lines at this time are kept low. Word line W 1 is accessed by applying to it a logical high sufficient to forward bias the base-emitter junction of transistor T 11 . All other word lines are kept low at this time. Bit line B 1 is connected to a source of high positive potential sufficient to cause enough current to flow through transistor P 11 to short the collector-emitter junction of transistor P 11 . With a high on word line W 1 , access transistor T 11 turns on. The source of high potential connected to bit line B 1 is connected to collector 4 of programming transistor P 11 through access transistor T 11 . Programming transistor P 11 conducts, due to the high potential connected to its collector 4, a current sufficient to cause reverse breakdown of its collector-base junction. With emitter 6 being connected to bias line 91, which is at ground, the base-emitter junction is forward biased. Programming transistor P 11 is constructed such that sufficient current is applied during programming from bit line B 1 to cause a permanent short to be created between collector 4 and emitter 6. Access transistor T 11 is constructed such that it can carry this programming current without itself becoming damaged. Because access transistor T 11 is rather large, the speed of cell 11 is rather low. Each cell in memory array 100 which is to be programmed is programmed by this method.
During the read operation of memory cell 11, bias line 91 is connected to ground, bit line B 1 is accessed by applying to it a logical high (i.e. a positive voltage sufficient to allow reading of cell 11, but insufficient to generate enough current through transistor P 11 to short the collector-emitter junction of transistor P 11 ), and word line W 1 is accessed by applying to it a logical high sufficient to forward bias the base-emitter junction of transistor T 11 . With bit line B 1 and word line W 1 high, access transistor T 11 will conduct, applying the logical high from bit line B 1 to collector 4 of programming transistor P 11 . If programming transistor P 11 has been programmed, the high applied to collector 4 will cause current to flow through the short created between collector 4 and emitter 6 of programming transistor P 11 to bias lead 91, which is at ground. The current flow through access transistor T 11 and programming transistor P 11 to ground causes bit line B 1 to be pulled low. This low is applied to sense amplifier A 1 , resulting in an output signal being applied to output terminal O 1 indicative of the fact that programming transistor P 11 has been programmed (i.e. has a short circuit). On the other hand, if programming transistor P 11 had not been programmed, current would not flow between collector 4 and emitter 6 of programming transistor P 11 , because base 5 is not high. Thus, when an unprogrammed cell 11 is accessed, bit line B 1 will remain high. This high is applied to amplifier A 1 , and the output signal available at O 1 is indicative of memory cell 11 being unprogrammed.
A major difficulty associated with this prior art method of utilizing bipolar transistors as programming means is that each access transistor associated with a single programming transistor must be capable of carrying the high programming current without itself being damaged. Since the current required to program a bipolar transistor is on the order of 200 milliamps, the access transistor of prior art PROMs must be constructed to be rather large in order to be able to handle 200 milliamps without incurring any damage when the memory cell is programmed by fusing a transistor junction. Because of the required large size of the access transistors of such prior art PROMs, the speed of such prior art PROMs is rather low.
Another prior art method of constructing PROMs is to utilize refractory metal, such as nichrome, titanium-tungsten, or polycrystalline silicon, in such a manner as to form a fusible link. Such a fusible link is shown in FIGS. 3a and 3b. Fusible link 71 contains narrow region 72 such that region 72 acts as a fuse. When sufficient current is caused to flow through narrowing 72, the material is melted, thus forming opening 73 as shown in FIG. 3b. The circuit of FIG. 2 can be used to construct a PROM utilizing fusible links, where each programming transistor P 11 , P 12 , P 21 , and P 22 is replaced by a single fusible link. Programming and reading takes place in precisely the same manner as in the circuit shown in FIG. 2, with the exception that programmed cells contain open fuses rather than shorted transistors. Typical current required to blow open a fusible link is again on the order of 70 to 200 milliamps. Thus, this technique also requires that each access transistor be rather large in order to carry the current required to program each fusible link without itself incurring any damage; the speed of such prior art PROM devices utilizing fusible links is rather slow.
Prior art PROMs are disclosed, for example, in U.S. Pat. Nos. 3,191,151; 3,733,690; 3,742,592 and 3,848,238.
SUMMARY OF THE INVENTION
In accordance with this invention, prior art difficulties in the manufacture of high speed programmable read only memories are overcome by utilizing a programming transistor capable of switching high programming currents, and a read transistor capable of sensing the state of the cell (i.e. programmed or unprogrammed). The programming transistor, utilized only when programming the cell, being rather large, is rather slow. The read transistor, utilized only when reading the cell, is constructed to be as small as possible, thereby achieving a substantially increased reading speed over prior art PROM devices which utilize a single transistor per memory cell for both programming and reading.
DESCRIPTION OF THE DRAWING
FIGS. 1a and 1b show in cross-section a bipolar transistor of the prior art before and after programming;
FIG. 2 shows a schematic diagram of a prior art PROM device which utilizes a single accessing transistor per cell for both programming and read operations;
FIGS. 3a and 3b show a top-view of a prior art fusible link;
FIG. 4 is a schematic diagram of a PROM device constructed in accordance with this invention; and
FIG. 5 is a detailed schematic diagram of portions of the circuit of FIG. 4.
DETAILED DESCRIPTION
A schematic diagram of a PROM device constructed in accordance with this invention is shown in FIG. 4. PROM device 100 comprises a plurality of N word lines, W 1 , W 2 , . . . W N and a plurality of M bit lines, B 1 , B 2 . . . B M . A plurality of N X M cells are formed, with each cell being formed at the "intersection" of a single word line and a single bit line. For example, cell 11 is formed at the "intersection" of word line W 1 and bit line B 1 . Note that word line W 1 and bit line B 1 are not directly connected, but rather are connected only through transistor T 11 and fusible link F 11 . Fusible link F 11 may comprise nichrome, polycrystalline silicon, titanium tungsten, a fusible diode or a transistor junction, or any suitable means which is capable of being changed from one state to another state (such as from a short circuit to an open circuit) during programming. Each of the cells of the array functions in indentical manner to cell 11. Thus only the operation of cell 11 will be discussed.
Connected to bit line B 1 is programming and sensing means 200. Programming and sensing means 200 serves to program the various fusible links F 11 , F 21 , . . . F N1 connected to bit line B 1 . Programming and sensing means 200 also serves to sense the logical state (i.e, programmed or unprogrammed) of each fusible link F 11 through F N1 connected to bit line B 1 . It is to be understood that programming and sensing means identical to means 200 is connected to each bit line B 1 , B 2 , . . . B M in order to provide programming and sensing functions for each cell of the array. However, in this specification only the operation of programming and sensing means 200 will be described.
Typically the structure shown schematically in FIG. 4 is formed as an integrated circuit on a single chip of silicon semiconductor material.
The programming of cell 11 will now be described. It is to be understood that each cell within the array of PROM 100 is programmed in a similar manner. The collector of transistor T 11 is connected to a positive voltage supply V CC , as are the collectors of each of the N x M transistors contained in the N x M memory cells of PROM device 100. The base of transistor T 11 is connected to word line W 1 . Word line W 1 , which connects to the to-be-programmed memory cell 11, is enabled by connection to a positive voltage (logical 1) (not shown). All other word lines W 2 through W N are disabled by connection to a low voltage (logical 0). This low voltage applied to disable word lines W 2 -W N turns off each transistor connected to word lines W 2 -W N , thus disabling all transistors connected to word lines W 2 -W N .
During programming of cell 11, the positive supply voltage V CC applied to the collector of T 11 is increased to approximately 12 volts, as compared with the typical value of 5 volts used during the read operation of the device. During programming of cell 11, the output terminal O 1 (part of programming and sensing means 200) is also connected to 12 volts if it is desired to change fusible link F 11 to an open circuit, and the output terminal O 1 is connected to ground (or a voltage less than approximately 6-7 volts, the breakdown voltage of zener diode 56) if it is desired to maintain fusible link F 11 as a short circuit.
The application of V CC of 12 volts to the PROM device causes inverter 57 to become disabled, with the input lead and the output lead of inverter 57 floating. The disabling circuitry of inverter 57 is of a type well known to those skilled in the art. An example of a circuit which is used as inverter 57 is shown in FIG. 5, discussed below. During programming, V CC =12 volts is also applied to terminal 50. Terminal 50 is connected to the base of transistor 53 through resistor 51 (approximately 3000 ohms). During programming, the input lead of inverter 57 is disabled, thus causing the emitter of transistor 53 to float. Thus, transistor 53 remains turned off during programming.
During the programming operation, an entire word accessed by word line W 1 is programmed simultaneously. Thus, each fusible link accessed by word line W 1 is programmed simultaneously by the application of bits forming the word to be stored on word line W 1 applied to output terminals O 1 through O M . Of importance, if the PROM device of this invention is in the programming mode (i.e. V CC raised to approximately 12 volts) each fusible link connected to the enabled word line will be programmed, or changed from a short circuit to an open circuit, only if the voltage on its associated output terminal O 1 . . . O M is equal to approximately 12 volts.
To program cell 11 to a logical 1 (open fusible link F 11 ), word line W 1 is accessed and a programming voltage of approximately 12 volts is applied to output terminal O 1 . During programming (V CC ≅12 volts ), the input lead of inverter 57 is floating (high impedance). Thus, inverter 57 will not sink emitter current from NPN transistor 53, thus keeping transistor 53 turned off during programming. Zener diode 56, having a zener breakdown voltage of approximately 6 volts, conducts, thus forward biasing the base-emitter junction of transistor 55, thereby causing transistor 55 to conduct. At the same time, V CC is supplied to terminal 50. With V CC =12 volts applied to terminal 50, zener diode 52, having a zener breakdown voltage of approximately 6 volts, conducts, thus forward biasing the base-emitter junction of transistor 54, thereby turning on transistor 54. Approximately 50 milliamps of current then flows from the collector of transistor T 11 contained within memory cell 11 (connected to V CC =12 volts), through transistor T 11 , through fusible link F 11 , and through transistors 54 and 55 to ground. During programming, which takes approximately 1 millisecond, fusible link F 11 is changed from a short circuit (a first selected state such as a logical 0) to an open circuit (a second selected state such as a logical 1).
On the other hand, when it is desired to program word line W 1 and maintain cell 11 in the first selected state (arbitrarily defined to be a logical 0 corresponding to a shorted fusible link F 11 ), a programming voltage of approximately 0 volts (or any voltage less than the zener breakdown voltage of zener diode 56) is applied to output node O 1 . Zener diode 56 wil not conduct, transistor 55 will not be turned on, and thus current will not be drawn through fusible link F 11 . Fusible link F 11 will thus remain a short circuit indicating that a logical 0 is stored in memory cell 11.
Each word stored within PROM 100 is programmed in a similar manner, by applying V CC ≅12 volts to the collector of the transistors corresponding to T 11 in each cell connected to the word line W i ; enabling the corresponding word line W i (where i is an integer given by 1≦i≦N) to be programmed, and applying a high voltage of approximately 12 volts to those output terminals O 1 -O M corresponding to those bits of the selected word which are to be stored as logical ones (i.e. those bits to have the link corresponding to link F 11 open-circuited), with all other output terminals being connected to a low voltage of approximately zero volts.
During the read operation of the PROM device of this invention, the positive supply voltage V CC applied to the PROM device is equal to approximately 5 volts. Approximately 5 volts is thus available on the collector of transistor T 11 of cell 11 and all other corresponding transistors of the memory array. V CC of 5 volts is also applied to terminal 50. Because the voltage applied to terminal 50 is less than the six (6) volt zener breakdown voltage of zener diode 52, zener diode 52 does not conduct and programming transistor 54 is not turned on during the read operation. Similarly, the highest output voltage available from inverter 57 is approximately V CC =5 volts; thus zener diode 56, having a zener breakdown voltage of 6 volts, does not conduct and transistor 55 is not turned on during the read operation.
However, during the read operation, the V CC of 5 volts applied to terminal 50 is also applied through resistor 51 (approxmately 3000 ohms) to the base of transistor 53. This voltage applied to the base of transistor 53 is sufficient to forward bias the base-emitter junction of transistor 53, thus causing transistor 53 to turn on. Using suitable well-known addressing techniques, the desired word line W i is enabled by connection to a logical one (a positive voltage), and all other word lines are disabled by connection to a logical zero. For example, if it is desired to read the contents of memory cell 11, word line W 1 is enabled by placing a positive voltage on word line W 1 . All other word lines W 2 through W N are disabled by their connection to a logical low, typically zero volts. If fusible link F 11 is intact (i.e. unprogrammed, or a short circuit), with the base of access transistor T 11 connected to a logical high, the base-emitter junction of access transistor T 11 will be forward biased and transistor T 11 will conduct, thereby applying a positive voltage on the collector of transistor 53. With approximately 5 volts applied to the collector of transistor 53, and transistor 53 turned on during the read operation, as previously described, sufficient current is provided to the input of inverter 57 to generate a logical low signal on the output lead of inverter 57, which serves as the output signal on output terminal O 1 representing the state of cell 11.
On the other hand, if fusible link F 11 in cell 11 has been programmed to be an open circuit, transistor T 11 cannot turn on, and the positive voltage applied to the collector of transistor T 11 will not be applied to the collector of transistor 53. With the collector of transistor 53 floating, the current applied to the input lead of inverter 57 is due to the forward biased base-emitter junction of transistor 53. This base-emitter current is negligible (approximately 400 microamps) thus causing the output voltage of inverter 57 to go high, thereby providing a logical 1 of approximately 5 volts on the output terminal O 1 , thus indicating that the fusible link F 11 in cell 11 is programmed to be an open circuit. As previously mentioned, this output voltage of 5 volts is insufficient to cause zener breakdown of zener diode 56, which has a zener breakdown voltage of approximately 6 volts. Thus, zener diode 56, and programming transistor 55 remain non-conducting during the read operation.
In order to allow for high speed reading, the read transistor 53 of this invention is preferably a Schottky transistor, such as is well known in the semiconductor arts. The operation of a Schottky transistor is well known an provides increased switching speeds over conventional bipolar and MOS transistors.
Thus, it is seen that during the reading of the PROM of this invention, the slow transistors which are capable of handling large programming currents (such as transistors 54 and 55 used to program the cells in column 1) are inactive and the reading is carried out by smaller, fast transistor 53. On the other hand, when a cell is being programmed, read transistor 53 and inverter 57 are disabled and thus not exposed to potential damage by the large currents used during the destruction of fusible link F 11 .
In another embodiment of this invention, the subcircuit 157 comprising NPN transistor 55 and zener diode 56 of programming and sensing means 200 (FIG. 4) is replaced by circuit 157 shown in FIG. 5. When a programming voltage (typically 12 volts) is applied to output terminal O 1 which exceeds the zener breakdown voltage of zener diode Z 11 (typically 6 volts), diode Z 11 conducts, thus providing base current through resistor R 66 (3K ohms) to transistor Q 58 . The base of NPN transistor Q 58 is normally kept low by transistor R 67 (10K ohms) connected to ground, and the emitter of transistor Q 58 is connected to ground through resistor R 68 (5K ohms). The base current to transistor Q 58 provided by a programming voltage on output terminal O 1 turns transistor Q 58 on, thus drawing current from V CC to ground through collector resistor R 65 (750 ohms) and emitter resistor R 68 (5K ohms). This causes the base of NPN transistor Q 59 to go high, thus turning on transistor Q 59 . Transistor Q 59 thus draws collector current from V CC to ground through collector resistor R 65 and emitter resistor R 69 (1K ohm). This causes a high voltage to be placed on the base of NPN transistor Q 60 . Because the emitter of transistor Q 60 is grounded, transistor Q 60 thus turns on, thus drawing a large amount of programming current (approximately 50 ma) from terminal 157A. As shown in FIG. 4, terminal 157A is connected to the emitter of transistor 54, which as previously described is on during programming. Thus, this programming circuit is drawn from V CC , through access transistor T 11 , through fusible link F 11 , through bit line B 1 , through transistor 54, and sub-circuit 157 to ground, thus causing the fusion, or opening of fusible link F 11 , when memory cell 11 is programmed. Resistor R 64 (8K ohms) connected between V CC and the collector of transistor Q 60 serves to provide a high voltage (V CC ) to terminal 157A when transistor Q 60 is turned off (i.e. during nonprogramming and during programming when a low voltage is applied to output terminal O 1 ). This high voltage on terminal 157A is applied to the emitter of transistor 54 (FIG. 4) thus keeping transistor 54 turned off and reducing the capacitance of transistor 54, thus increasing the speed of the circuit when transistor Q 60 is off. The zener diode Z 11A , having a zener breakdown voltage of approximately 6 volts, is connected between the collector of transistor Q 60 and ground, and serves to maintain the voltage on terminal 157A at approximately 6 volts during programming (V CC ≅12 volts) when transistor Q 60 is off (logical low on output terminal O 1 , or enable terminal 159 low), in order to prevent breakdown of the emitter-base junction of transistor 54 (FIG. 4). Schottky diode D 28 , having a forward voltage of approximately 0.4 volts is connected between the base of transistor Q 58 and enable terminal 159 and serves to keep transistors Q 58 , Q 59 and Q 60 turned off during times when a high enable signal is not present on enable terminal 159. With a low voltage (0 volts) applied to enable terminal 159, a high voltage (12 volts) applied to the output terminal O 1 will not cause the base of transistor Q 58 to exceed approximately 0.4 volts, thus keeping transistor Q 58 turned off. With transistor Q 58 off, transistors Q 59 and Q 60 also remain turned off. Thus, programming does not take place when a logical low is applied to enable terminal 159.
A detailed schematic diagram of inverter 57 (FIG. 4) is shown in FIG. 5. Resistor R 61 (4.5K ohms) is connected to the collector and base of NPN transistor Q 56 , whose emitter is connected to ground. This causes transistor Q 56 to turn on, and provide a substantially constant bias voltage to the base of NPN transistor Q 55 . The emitters of transistor Q 55 are connected to ground and transistor Q 55 serves as a current source tending to pull down node 141 to ground. When V CC is raised to the programming voltage (approxmately 12 volts), zener diode Z 12 (having a zener breakdown voltage of approximately 6 volts) conducts, thus supplying current to resistors R 62 (6K) and R 63 (3K), thus providing a base voltage to NPN transistor Q 57 . This causes transistor Q 57 to conduct thus grounding the bases of transistors Q 55 and Q 56 , thus turning off transistors Q 55 and Q 56 . With transistor Q 55 turned off during programming input terminal 142 provides a high impedance input lead of inverter 57. Node 141, connected to terminal 142, serves as the input node of inverter 57, as shown in FIG. 4.
During reading (V CC ≅5 volts), with a low voltage placed on input terminal 142 of inverter 157, input node 141 is pulled low by current source transistor Q 55 . The low voltage on node 141 causes Schottky diode D 25 to conduct current from V CC through resistor R 51 (8K), thus maintaining the bases of NPN Schottky transistors Q 48 and Q 49 low. Thus, transistors Q 48 and Q 49 do not conduct, and the voltage applied to the base of transistor Q 53 is kept low by resistor R 57 (900 ohms) connected between the base of transistor Q 53 and ground. Thus, transistor Q 53 does not conduct. However, with transistor Q 49 turned off, a high voltage is placed on the base of NPN transistor Q 51 from V CC through resistor R 53 (3K). The emitter of transistor Q 51 is connected to the base of NPN transistor Q 52 and to ground through resistor R 58 (5K). Thus, transistor Q 51 turns on, thus drawing collector current from V CC through resistor R 54 (50 ohms), and thus providing a high voltage on the base of NPN transistor Q 52 . Thus, transistor Q 52 turns on, providing a low impedance path between V CC through resistor R 54 (50 ohms) through transistor Q 52 to output terminal O 1 . Thus, with a low signal applied to input terminal 142 of inverter 57, a high-voltage signal is placed on output terminal O 1 of inverter 57. In fact, with a logical zero applied to input terminal 142, transistor Q 49 is not completely off, but rather conducts a small amount of current. Resistor R 57 may be replaced by a resistor of approximately 6000 ohms, and an additional NPN Schottky transistor (not shown) having its emitter grounded, its base connected to the emitters of transistors Q 48 and Q 49 through a first 900 ohm resistor and its collector connected to the emitters of transistors Q 48 and Q 49 through a second 900 ohm resistor. With transistor Q 49 non-conducting (logical zero on input terminal 142), this alternative circuitry decreases the collector current through transistor Q 49 , thus decreasing the voltage drop across resistor R 53 , thereby increasing the voltage applied to the base of transistor Q 51 . Because the output voltage corresponding to a logical one on terminal O 1 is two forward biased diode voltage drops less than the voltage on the base of transistor Q 51 (i.e. the base-emitter voltage drops of transistors Q 51 and Q 52 ), the output voltage corresponding to a logical one on terminal O 1 is increased as compared to the logical one output voltage of the circuit of FIG. 5.
On the other hand, if during reading (V CC ≅5 volts) a logical high signal is placed on input terminal 142 of inverter 57, current source Q 55 is unable to maintain node 141 at ground, and thus Schottky diode D25 does not conduct. Thus, a high voltage is placed on the bases of transistors Q 48 and Q 49 from V CC through resistor R 51 , thus causing transistors Q 48 and Q 49 to turn on. With transistors Q 48 and Q 49 conducting, a voltage sufficient to forward bias the base-emitter junction of transistor Q 53 is applied to the base of transistor Q 53 , thus causing transistor Q 53 to conduct, which in turn grounds output node O 1 . With transistor Q 53 conducting, the voltage on the base of transistor Q 53 (approximately 0.6 volts), and the voltage on the collector of transistor Q 49 (approximately 0.7 volts) are sufficiently low to prevent transistors Q 51 and Q 52 from turning on. Thus, with a logical high placed on input terminal 142 of inverter 57, a low impedance logical low is placed on output terminal O 1 inverter 57.
During programming, V CC is raised to approximately 12 volts. This causes zener diode Z 12 , having a zener breakdown voltage of approximately 6 volts, to conduct thus causing current to flow through resistors R 1 (6000 ohms) and R 2 (3 Kohms) to ground. The voltage at the node between R 1 and R 2 is applied as a base voltage to NPN transistor Q 47A , causing transistor Q 47A to conduct and saturate, thus decreasing the voltage on the bases of transistors Q 48 and Q 49 to approximately zero volts. Similarly, during programming, a logical low is placed on enable terminal 159, thus causing Schottky diodes D 26 and D 27 to pull down the voltages on the bases of transistors Q 48 and Q 49 , and the voltage on the base of transistor Q 51 , respectively. Thus, during programming transistors Q 48 , Q 49 , and thus transistor Q 53 are turned off. Also during programming, transistors Q 51 and thus transistor Q 52 , are turned off. Thus, during programming, output terminal O 1 is neither a logical low or a logical high, but rather is floating such that a high impedance is presented between output terminal O 1 and V CC and ground within inverter 57. The fact that output terminal O 1 is floating during programming means that the programming signal applied externally to output node O 1 is applied to subcircuit 157 without being influenced by inverter 57. Thus, during programming a high or low programming signal is not generated on output terminal O 1 by inverter 57, but rather must be applied externally in accordance with the program desired to be stored within the PROM device of this invention.
While one embodiment of this invention has been described, this description is not intended to be limiting and other embodiments will be obvious to those skilled in the art based on this disclosure. Thus, while this invention has been described as using a fusible link 11, the principles of this invention apply equally well to the use of any other fusible element, such as one or more PN junctions or a dielectric. | A semiconductor memory device (100) utilizing a programming transistor (54) capable of switching high programming currents, and a read transistor (53) capable of sensing the state of the cell (i.e. programmed or unprogrammed). The programming transistor, utilized only when programming the cell, being rather large, is rather slow. The read transistor, utilized only when reading the cell, is constructed to be as small as possible, thereby achieving a substantially increased reading speed over prior art PROM devices which utilize a single transistor per memory cell for both programming and reading. | 6 |
FIELD OF THE INVENTION
[0001] The present invention relates generally to optical discs and methods and arrangements for labeling the same.
BACKGROUND OF THE INVENTION
[0002] Direct disc labeling techniques have recently been introduced in optical disc drive (ODD) recorders, and this has provided an advanced capability to “burn” high quality monochromatic labeling information directly onto recordable optical discs using the drive recorder's existing data read/write laser optics system. Presently, two methods are generally employed to implement such direct disc labeling systems.
[0003] In a first method, an organic dye polymer coating is utilized on the label side of the disc. When the disc is then inserted into the drive recorder “upside down”, this enables the “burning” of selected portions of the disc by the drive's data recording laser to create contrasting elements in the dye, thus realizing text and art images that are visible to the naked eye. Hewlett-Packard employs this method in its “LIGHTSCRIBE” direct disc labeling technology.
[0004] In a second method, as employed in Yamaha's “LABELFLASH” direct disc labeling technology, a visible image is created by utilizing an organic dye data layer on the opposite side of double-sided recordable media. Instead of recording data on the opposite side, a label image is recorded. The end result is that the label image is actually beneath the surface of the media, whereas with the first method the image is on the surface of the media.
[0005] Both conventional implementations outlined above are limited in that the images created on the disc are monochromatic, since the effect of heating the label or data dye layer is to cause any existing colored dye to turn gray or black. So while the original color of the dye is selectable (albeit within limits), the contrasting areas created by the localized heating of the focused recording laser will be grayscale; thus the created image ends up being monochromatic.
[0006] U.S. Pat. No. 6,778,205, assigned to Hewlett-Packard, largely describes monochromatic processes of the type utilized in “LIGHTSCRIBE” products as discussed above. At the same time, any conceivable manner of effecting colored labels with such technology would likely be cumbersome, inefficient and lacking in versatility.
[0007] In view of the foregoing, a compelling need has been recognized in connection with providing a direct disc labeling technique that improves upon conventional efforts, especially by way of improving upon the monochromatic images brought about by such efforts.
SUMMARY OF THE INVENTION
[0008] Broadly contemplated herein, in accordance with at least one presently preferred embodiment of the present invention, is a full-color direct disc labeling method that solves the monochromatic limitation associated with current direct disc labeling techniques. The techniques disclosed herein provide a unique, cost-effective method of implementing full-color direct disc labeling in the emerging class of blue laser optical drive recorders, known by trade names such as Blu-ray and HD DVD.
[0009] In summary, one aspect of the invention provides an apparatus comprising: a disk drive; the disk drive comprising a plurality of lasers, each laser acting to read and record data from and to a disc; a detection module which ascertains a position of a disc in the disk drive; each laser acting to alter an appearance of a portion of a disc in the disk drive; the lasers cooperating with the detection module to impart a predetermined pattern to a disc.
[0010] Another aspect of the invention provides a method comprising the steps of: inserting a disc into a disk drive; ascertaining a position of the disc within the disc drive; imparting a predetermined, position-based pattern to the disc; the imparting comprising: activating a first laser to alter an appearance of a first portion of the disc; and activating a second laser to alter an appearance of a second portion of the disc.
[0011] Furthermore, an additional aspect of the invention provides a program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform a method comprising the steps of: inserting a disc into a disk drive; ascertaining a position of the disc within the disc drive; imparting a predetermined, position-based pattern to the disc; the imparting comprising: activating a first laser to alter an appearance of a first portion of the disc; and activating a second laser to alter an appearance of a second portion of the disc.
[0012] For a better understanding of the present invention, together with other and further features and advantages thereof, reference is made to the following description, taken in conjunction with the accompanying drawings, and the scope of the invention will be pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1A schematically illustrates a computer system.
[0014] FIG. 1 graphically illustrates dye sensitivities as a function of the wavelengths of different lasers.
[0015] FIG. 2 provides a cross-sectional view of a three-layer full-color direct label disc.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] For a better understanding of the present invention, together with other and further features and advantages thereof, reference is made to the following description, taken in conjunction with the accompanying drawings, and the scope of the invention will be pointed out in the appended claims.
[0017] It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the apparatus, system, and method of the present invention, as represented in FIGS. 1A through 2 , is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.
[0018] One or more functional units described in this specification may be labeled as a “module”, in order to more particularly emphasize their implementation 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.
[0019] 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.
[0020] Indeed, a module of executable code could 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.
[0021] Reference throughout this specification to “one embodiment” or “an embodiment” (or the like) 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” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.
[0022] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
[0023] The illustrated embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals or other labels throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the invention as claimed herein.
[0024] One possible implementation of at least one embodiment of the present invention is in the disk drive of a computer system, though of course other disk drives (e.g., stand-alone disc players and recorders) can serve as an environment for one or more embodiments of the present invention. Referring now to FIG. 1 , there is depicted a block diagram of an illustrative embodiment of a computer system 12 . The illustrative embodiment depicted in FIG. 1 may be a notebook computer system, such as one of the ThinkPad® series of personal computers sold by Lenovo (US) Inc. of Morrisville, N.C., however, as will become apparent from the following description, the present invention is applicable to any data processing system.
[0025] As shown in FIG. 1 , computer system 12 includes at least one system processor 42 , which is coupled to a Read-Only Memory (ROM) 40 and a system memory 46 by a processor bus 44 . System processor 42 , which may comprise one of the AMD™ line of processors produced by AMD Corporation or a processor produced by Intel Corporation, is a general-purpose processor that executes boot code 41 stored within ROM 40 at power-on and thereafter processes data under the control of operating system and application software stored in system memory 46 . System processor 42 is coupled via processor bus 44 and host bridge 48 to Peripheral Component Interconnect (PCI) local bus 50 .
[0026] PCI local bus 50 supports the attachment of a number of devices, including adapters and bridges. Among these devices is network adapter 66 , which interfaces computer system 12 to LAN 10 , and graphics adapter 68 , which interfaces computer system 12 to display 69 . Communication on PCI local bus 50 is governed by local PCI controller 52 , which is in turn coupled to non-volatile random access memory (NVRAM) 56 via memory bus 54 . Local PCI controller 52 can be coupled to additional buses and devices via a second host bridge 60 .
[0027] Computer system 12 further includes Industry Standard Architecture (ISA) bus 62 , which is coupled to PCI local bus 50 by ISA bridge 64 . Coupled to ISA bus 62 is an input/output (I/O) controller 70 , which controls communication between computer system 12 and attached peripheral devices such as a keyboard, mouse, and disk drive 72 . In addition, I/O controller 70 supports external communication by computer system 12 via serial and parallel ports. Of course, it should be appreciated that the system 12 may be built with different chip sets and a different bus structure, as well as with any other suitable substitute components, while providing comparable or analogous functions to those discussed above.
[0028] Disk drive 72 may preferably be configured to accommodate CD, DVD and Blu-ray discs as discussed herebelow not only for reading purposes but also for recording (“burning”) purposes. Disk 72 may preferably be functionally integrated with a disc position detection module 74 to be described more fully below. As discussed herebelow, a disk drive 72 may preferably include three lasers for reading and/or burning purposes, and these may be employed for imparting a colored label to a disc in manners now to be described.
[0029] Generally, optical disc drive recorders utilizing 405 nm wavelength blue-violet lasers have been developed to achieve much higher recording densities compared to the predecessor 650 nm red laser DVD and 780 nm infrared laser CD recorders. However, for full backward compatibility with existing CD and DVD media, integrated optical pickup (OPU) units utilizing three laser optics systems (405, 650, and 780 nm) are now being implemented on most commercially available drives.
[0030] Another technology recently developed is that of semi-transparent organic dye polymers that are used for two-layer DVD+/-R recording. These polymers allow unfocused laser light to pass through a top layer to enable a focused spot on the underlying second layer for data recording and playback.
[0031] Accordingly, in accordance with at least one presently preferred embodiment of the present invention, the aforementioned triple-wavelength integrated optical systems and semi-transparent organic dye layers may be employed to create full-color human-readable labels directly on recordable discs.
[0032] As part and parcel of a process according to at least one embodiment of the present invention, organic dyes currently used in one-time recordable CD (CD-R), DVD (DVD-R and DVD+R), and Blu-ray/HD DVD (BD-R/HD DVD-R) discs are wavelength sensitive; i.e., they are “tuned” to react to a narrow wavelength band surrounding the recording laser wavelength. To illustrate this phenomenon, FIG. 1 graphically illustrates dye sensitivities as a function of the wavelengths of the three lasers in question.
[0033] Furthermore, semi-transparent versions of these dyes can be made that allow unfocussed laser light to pass through them; these are currently utilized in DVD, HD DVD, and Blu-ray multi-layer recordable media. Preferably, such properties are utilized in accordance with at least one presently preferred embodiment of the present invention to create full-color visible images on specially-prepared recordable media, and as can be seen in FIG. 2 (a cross-sectional view of a three-layer full-color direct label disc). Preferably, one side of the medium, the “data” side 0 , contains the traditional CD, DVD, or Blu-ray/HD DVD data recording layer(s). The opposite side of the medium, however (“label” side 0 ′) preferably contains three layers of semi-transparent organic dye ( 1 , 2 , 3 ), with each layer corresponding to one of three primary colors red, green, blue, or their complements magenta, yellow, cyan (before burning). These three layers are sandwiched between a fully-transparent top protective layer 4, and a fully reflective bottom layer 5.
[0034] Accordingly, each of the three dye layers 1/2/3 is preferably sensitive to one of the three laser wavelengths (405, 650, or 780 nm), and will darken when focused light of sufficient power in the sensitive range is applied. By modulating the three drive lasers (blue 5 , red 6 and infra-red 7 ) as they pass over the label side 0 ′ of the disc (either serially or in parallel, depending on the OPU design), areas of each primary color can be selectively neutralized (darkened or “burned”) to create a full-color image from the three primary color layers on the disc, analogous to the way wavelength-sensitive silver halides are selectively darkened in three-layer photographic film emulsions to create full-color images. Non-coherent white light ( 8 ) will of course pass through all three layers 1/2/3 and be reflected back from bottom layer 5.
[0035] In brief recapitulation, it should be appreciated and understood, with reference to FIG. 2 , that preferably there may be three stacked layers of dye 1 / 2 / 3 provided on a “label” side 0 ′ of a disc, and each of the three layers 1/2/3 is preferably responsive to a different one of the three lasers 5 / 6 / 7 of a disc drive. Since shorter wavelengths translate to shorter focus depths, the layer 1 responsive to blue laser 5 is preferably provided on top, followed by the layer 2 responsive to red laser 6 , followed by a layer 3 responsive to infrared laser 7 . Since the dyes in layers 1/2/3 are configured to be sensitive solely to specific wavelengths (or wavelength ranges), then a given laser 5 / 6 / 7 will not be fully focused when passing through one or more specific layers other than the “target” layer for that laser. For instance, the infra-red laser 7 will not be in full focus when passing through dye layers 1 and 2, since these layers are not sensitive (and thus not responsive to) the characteristic infrared laser wavelength(s).
[0036] In an alternative implementation in accordance with the present invention, dyes may preferably be provided for layers 1, 2 and 3 that turn clear when exposed to given laser lights (rather than going opaque as in the case outlined just above).
[0037] An alternative implementation is also conceivable, wherein a single-layer emulsion of three primary color dyes is applied to the label side, with each dye component reacting to its respective laser wavelength sensitivity to create full-color images in a single layer using the three wavelengths available in the drive OPU. Using these techniques, cost-effective full-color direct disc labeling can be achieved to improve upon conventional monochromatic arrangements. Though a wide variety of implementations are possible, a favorable implementation could preferably involve the combination of the three colors into a single emulsion, whereby primary color component would react only to its specific wavelength sensitivity.
[0038] In order to implement one or more embodiments as broadly contemplated herein in accordance with the present invention, a disk drive 72 (see FIG. 1 ) may preferably include a capability ( 74 ) for detecting the position of a disc inserted into the drive. This “disc position detection” module 74 can be implemented as new or modified software incorporated into (or in functional connection with) drive 72 , or via a suitable sensor, or both. As such, a disc may include some type of encoding on its inner radius to “mark” a specific “home” or “zero” rotational position of the disc, while module 74 can preferably be configured to detect or ascertain the position of this “home” or “zero” at any time. Alternatively, a disc may include one or more “wobble grooves” distinct from the “spiral” grooves that normally contain data. This “wobble groove” could be embodied by a closed groove (i.e., it describes an arc about the disc's center of rotation of no more than 360 degrees) that defines a varying radius with respect to the disc's center of rotation. If the varying radius is in the form of, e.g., a sine wave, then preferably module 74 may be configured to count sine wave excursions so as to ascertain the rotational position of a disc. In any of these cases, ascertaining the rotational position of a disc will assist in imparting a desired, predetermined pattern or “label” to “label” side 0 ′ of a disc, e.g., by selectively activating and deactivating one or more of the lasers 5 / 6 / 7 at different times and in different positions (with respect to the disc) as the disc rotates.
[0039] It is to be understood that the present invention, in accordance with at least one presently preferred embodiment, includes elements that may be implemented on at least one general-purpose computer running suitable software programs. These may also be implemented on at least one Integrated Circuit or part of at least one Integrated Circuit. Thus, it is to be understood that the invention may be implemented in hardware, software, or a combination of both.
[0040] If not otherwise stated herein, it is to be assumed that all patents, patent applications, patent publications and other publications (including web-based publications) mentioned and cited herein are hereby fully incorporated by reference herein as if set forth in their entirety herein.
[0041] Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention. | A full-color direct disc labeling method that solves the monochromatic limitation associated with current direct disc labeling techniques. The techniques disclosed herein provide a unique, cost-effective method of implementing full-color direct disc labeling in the emerging class of blue laser optical drive recorders, known by trade names such as Blu-ray and HD DVD. | 1 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of abandoned U.S. application Ser. No. 08/234,032, filed Apr. 28, 1994, for Pressurized Fluidized Bed Combustion System and Method with Integral Recycle Heat Exchanger, incorporated herein by reference.
BACKGROUND OF THE INVENTION
This invention relates to a pressurized fluidized bed combustion system and method and, more particularly, to such a system incorporating a integral heat exchanger for recycling solids from the combustor.
According to prior art fluidized bed combustion systems and methods, air is passed through a bed of particulate material, including a fossil fuel, such as coal, and a sorbent for the oxides of sulfur generated as a result of combustion of the coal, to fluidize the bed and to promote the combustion at a relatively low temperature. These types of systems are often used in steam generators in which water is passed in a heat exchange relationship to the fluidized bed to generate steam and permit high combustion efficiency, fuel flexibility, high sulfur adsorption and low nitrogen oxides emissions. These types of systems often utilize a "circulating" fluidized bed in which the entrained solid particles of fuel and sorbent (hereinafter referred to as "solids") from the furnace are separated from the mixture of fluidizing air and combustion gases (hereinafter referred to as "flue gases") and are recycled back to the furnace.
In these circulating beds, the fluidized bed density is relatively low when compared to other types of fluidized beds, the fluidizing air velocity is relatively high, and the flue gases passing through the bed entrain a substantial amount of the fine solids to the extent that they are substantially saturated therewith.
The relative high solids recycling is achieved by disposing a cyclone separator at the furnace section outlet to receive the flue gases, and the solids entrained thereby, from the fluidized bed. The solids are separated from the flue gases in the separator and the flue gases are passed to a heat recovery area while the solids are recycled back to the furnace. This recycling improves the efficiency of the separator, and the resulting increase in the efficient use of sulfur adsorbent and fuel residence times reduces the adsorbent and fuel consumption. Also, the relatively high internal and external solids recycling makes the circulating bed relative insensitive to fuel heat release patterns, thus minimizing temperature variations and, therefore stabilizing the sulfur emissions at a low level.
When the circulating fluidized bed combustors are utilized in a steam generating system, the combustor is usually in the form of a conventional, water-cooled enclosure formed by a welded tube and membrane construction so that water and steam can be circulated through the wall tubes to remove heat from the combustor. However, in order to achieve optimum fuel burn-up and emissions control, additional heat must be removed from the system. This heat removal has been achieved in the past by several techniques. For example, the height of the furnace has been increased or heat exchange surfaces have been provided in the upper furnace to cool the entrained solids before they are removed from the furnace, separated from the flue gases and returned to the furnace. However these techniques are expensive and the heat exchange surfaces are wear-prone. Other techniques involve the deployment of an additional, separate heat exchanger between the outlet of the separator and the recycle inlet of the furnace. Although heat can be removed from the recycled solids in this separate heat exchanger before the solids are passed back into the furnace, these type of arrangements are not without problems. For example, it is difficult to precisely control the heat transfer rates in the recycle heat exchanger. Also, during startup or load low conditions, it is often difficult to bypass the heat exchange surfaces in the recycle heat exchanger. Further, in situations when the recycle heat exchanger is formed integrally with the furnace, there is often an increase in boiler plan area which adds to the cost of the system.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a fluidized bed combustion system in which a recycle heat exchanger is provided to remove heat from the recycled solids.
It is a further object of the present invention to provide a fluidized bed combustion system of the above type in which the amount of heat removed from the recycled solids can be precisely controlled.
It is a still further object of the present invention to provide a fluidized bed combustion system of the above type in which the recycle heat exchanger can be bypassed during startup and low load conditions.
It is a still further object of the present invention to provide a fluidized bed combustion system of the above type in which a pressurized system utilizing an outer pressure vessel is utilized to enable the above to be achieved without an increase in the size of the enclosing pressure vessel.
Towards the fulfillment of these and other objects, the fluidized bed combustion system of the present invention features a recycle heat exchanger disposed adjacent the furnace of a fluidized bed combustor. The recycle heat exchanger includes a plurality of stacked sections for receiving the recycled solids and cooling the solids. The heat exchanger sections are arranged in such a manner that the recycled solids are introduced into an upper level of the sections and pass through these sections to a lower level of sections before returning to the furnace.
BRIEF DESCRIPTION OF THE DRAWINGS
The above objects and summary, as well as further objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of the presently preferred, but nevertheless illustrative, embodiments of the present invention when taken in conjunction with the accompanying drawings wherein:
FIG. 1 is a schematic representation depicting the combustion system of the present invention;
FIG. 2 is a cross-sectional view taken along the line 2--2 of FIG. 1;
FIGS. 3 and 4 are cross-sectional views taken along the lines 3--3 and 4--4, respectively, of FIG. 2; and
FIG. 5 is a cross-sectional view taken along the line 5--5 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The drawings depict the fluidized bed combustion system of the present invention used for the generation of steam and including an upright pressure vessel 10 in which is disposed a water-cooled furnace enclosure, referred to in general by the reference numeral 12. The furnace enclosure 12 includes a front wall 14, a rear wall 15 and two sidewalls 16a and 16b (FIG. 3). As shown in FIG. 1, the lower portions 14a and 15a of the walls 14 and 15, respectively, converge inwardly for reasons to be explained. The upper portion of the enclosure 12 is enclosed by a roof 18a and a floor 18b defines the lower boundary of the enclosure. An air inlet duct 19 connects to the lower portion of the pressure vessel 10 for introducing pressurized air from an external source, such as a compressor driven by a gas turbine or the like.
A plurality of air distributor nozzles 20 are mounted in corresponding openings formed in a horizontal plate 22 extending across the lower portion of the enclosure 12. The plate 22 is spaced from the floor 18 to define an air plenum 24 which is adapted to receive air contained in the vessel 10 and selectively distribute the air through the plate 22 and to portions of the enclosure 12, as will be described.
It is understood that a fuel feeder system (not shown) is provided for introducing particulate material including fuel into the enclosure. The particulate material is fluidized by the air from the plenum 24 as it passes upwardly through the plate 22. The air promotes combustion of the fuel and the flue gases thus formed rise in the enclosure 12 by forced convection and entrain a portion of the solids to form a column of decreasing solids density in the enclosure to a given elevation, above which the density remains substantially constant.
A cyclone separator 26 extends adjacent the enclosure 12 inside the vessel 10 and is connected to the enclosure by a duct 28 extending from an outlet provided in the rear wall 15 of the enclosure to an inlet provided through the separator wall. The separator 26 receives the flue gases and the entrained particulate material from the enclosure in a manner to be described and operates in a conventional manner to disengage the particulate material from the flue gases due to the centrifugal forces created in the separator.
The separated flue gases, which are substantially free of solids enter a duct 30 projecting upwardly through the upper portion of the separator 26 and the vessel 10 for passage into a hot gas clean-up and a heat recovery section (not shown) for further treatment. The lower portion of the separator includes a hopper 26a which is connected to a conventional "J-valve" 32 by a dip leg 34.
A heat exchanger 38 is located adjacent the enclosure 12 and within the vessel 10, and is connected to the outlet of the J-valve 32 by a duct 39. The heat exchanger 38 includes an enclosure 40 formed by a front wall 42, a rear wall 43, two sidewalls 44a and 44b (FIG. 2), a roof 46a and a floor 46b. As shown in FIG. 1, the front wall 42 forms a lower extension of that portion of the rear enclosure wall 15 that extends just above the converging portion 15a. As shown in FIGS. 1 and 5, the plate 22 extends to the wall 42 to form a solids outlet compartment 50 defined above the latter extension and between the converging portion 15a of the enclosure rear wall 15 and the front wall 42 of the enclosure 40.
Two horizontally-extending, vertically-spaced, plates 54 and 56 (FIGS. 1 and 2) are disposed in the enclosure 40 and receive two groups of air distributor nozzles 58a and 58b, respectively. A third horizontally-extending plate 60 is disposed in the enclosure 40 and extends between the plates 54 and 56 to generally divide the enclosure into an upper portion and a lower portion. As shown in FIG. 2, a plenum section 61 is defined between the plates 54 and 60 for supplying air to the nozzles 58a, and a plenum section 62 is defined between the plate 56 and the floor 46b for supplying air to the nozzles 58b.
As shown in FIGS. 2 and 3, a pair of spaced, parallel vertical plates 64 and 66 extend between the rear wall 43 of the enclosure 40 and the wall 15 (and the wall 42) in a spaced parallel relationship to the sidewalls 44a and 44b. The plates 64 and 66 thus divide the upper portion of enclosure 40 into two heat exchange sections 68 and 70, respectively extending to the sides of a inlet/bypass section 72 (FIGS. 2 and 3). The plates 64 and 66 also divide the lower portion of the enclosure 40 into two heat exchange sections 74 and 76 respectively extending to the sides of a bypass section 78 (FIGS. 2 and 4). As shown in FIG. 2, three openings 64a, 64b, and 64c are formed in the plate 64 and three openings 66a, 66b and 66c are formed in the plate 66 to permit the flow of solids between the upper sections 68, 70, and 72, as well as between the lower sections 74, 76 and 78 as will be described.
The plates 64 and 66 also divide the plenum 61 into three sections respectively extending below the sections 74, 76, and 78 and, in addition, divide the plenum 62 into three sections respectively extending below the sections 74, 76, and 78.
It is understood that pressurized air from the vessel 10 is selectively introduced into the aforementioned plenum sections at varying velocities in a conventional manner, for reasons to be described.
As shown in FIG. 3, a vertical partition 80 extends from the horizontal plate 60 (FIG. 2) to the roof 46a and divides the inlet/bypass compartment 72 into two sections 72a and 72b. As shown in FIG. 5, the portion of the plate 54 that defines the compartment 60, as well as the corresponding portion of the plate 60, terminates at the partition 80 and thus do not extend to the wall 15 thus connecting the section compartment section 72b with the section 78 for reasons that will be described.
Four bundles 82a, 82b, 82c, and 82d of heat exchange tubes (FIGS. 2-4) are disposed in the heat exchange sections 68, 70, 74, and 76, respectively and are connected in a conventional manner to a fluid flow circuit (not shown) to circulate cooling fluid through the tubes to remove heat from the solids in the sections, in a conventional manner.
With reference to FIG. 5, an opening 80a is provided in the partition 80, a plurality of openings 42a are provided across the wall 42 and an opening 15b is provided in the wall 15 and as shown in FIGS. 2 and 5, three spaced openings 42a, 42b and 42c are provided through the wall 42 communicating with the sections 74, 78 and 76, respectively. The opening 80a is in the upper portion of the enclosure 40 and the opening 42a is at a higher level than the opening 15b, for reasons to be described. Also, two optional openings 15c and 15d can be provided in the upper portion of the wall 15a for venting the fluidizing air to the furnace at a higher level than the level of the opening 15b, as will be described.
It is understood that all of the foregoing walls, plates and partitions are formed of a conventional welded membrane and tube construction shown and described in U.S. Pat. No. 5,069,171 assigned to the assignee of the present application, the disclosure of which is incorporated by reference. It is also understood that a steam drum is provided adjacent the vessel and a plurality of headers, downcomers and the like are provided to establish a fluid flow circuit including the foregoing tubed walls. Thus, water is passed in a predetermined sequence through this flow circuitry to convert the water to steam by the heat generated by the combustion of the fuel solids in the furnace enclosure 12.
In operation, the solids are introduced into the furnace enclosure 12 in any conventional manner where they accumulate on the plate 20. Air is introduced into the pressure vessel 10 and passes into the plenum 24 and through the plate 20 before being discharged by the nozzles 22 into the solids on the plate 20, with the air being at sufficient velocity and quantity to fluidize the solids.
A lightoff burner (not shown), or the like, is provided to ignite the fuel material in the solids, and thereafter the fuel portions of the solids is self-combusted by the heat in the furnace enclosure 12. The flue gases pass upwardly through the furnace enclosure 12 and entrain, or elutriate, a quantity of the solids. The quantity of the air introduced, via the plenum 24, through the nozzles 22 and into the interior of the enclosure 12 is established in accordance with the size of the solids so that a circulating fluidized bed is formed, i.e., the solids are fluidized to an extent that substantial entrainment or elutriation thereof is achieved. Thus, the flue gases passing into the upper portion of the furnace enclosure are substantially saturated with the solids and the arrangement is such that the density of the bed is relatively high in the lower portion of the furnace enclosure 12, decreases with height throughout the length of this enclosure and is substantially constant and relatively low in the upper portion of the enclosure.
The saturated flue gases in the upper portion of the furnace enclosure 12 exit into the duct 28 and pass into the cyclone separator 26. The solids are separated from the flue gases in the separator 26 in a conventional manner, and the clean gases exit the separator and the vessel 10 via the duct 30 for passage to hot-gas clean-up and heat recovery apparatus (not shown) for further treatment as described in the above-cited patent.
The separated solids in the separator 26 fall into the hopper 26a and exit the latter, via the dip leg 34 before passing through the J-valve 32 and, via the duct 39, into the enclosure 40 of the heat exchanger 38.
The separated solids from the duct 39 enter the inlet/bypass compartment section 72a of the enclosure 40 as shown by the flow arrow A in FIG. 3. In normal operation, air is introduced at a relatively high rate into the sections of the plenum 61 extending below the heat exchange sections 68 and 70 while air at a relatively low rate is introduced into the section of the plenum extending below the section 72a. As a result, the solids from the section 72a flow through the openings 64b and 66b (FIG. 2) in the partitions 64 and 66, respectively, and into the sections 68 and 70, as shown by the flow arrows B1 and B2 in FIGS. 2 and 3. The solids flow under and up through the heat exchange tube bundles 82a and 82b in the sections 68 and 70, as shown by the arrows C1 and C2 in FIGS. 2 and 3. The solids thus build up in the sections 68 and 70 and spill through the openings 64a and 66a in the partitions 64 and 66 respectively, into the inlet/bypass compartment section 72b, as shown by the flow arrows D1 and D2 in FIGS. 2 and 3. The solids then fall, by gravity through the openings in the plates 54 and 60, respectively, and into the lower section 78, as shown by the flow arrows E in FIG. 2.
Air at a relatively high rate is introduced into the sections of the lower plenum 62 extending below the lower heat exchange sections 74 and 76 while air at a relatively low rate is introduced into the section of the plenum 62 extending below the section 78. This promotes the flow of the solids from the section 78, through the openings 64c and 66c in the partitions 64 and 66, and into the heat exchange sections 74 and 76, as shown by the flow arrows F1 and F2, respectively, in FIGS. 2 and 4. The solids thus flow up through the tube bundles 82c and 82d in the sections 74 and 76, respectively, to transfer heat to the fluid flowing through the latter tubes. As shown in FIGS. 4 and 5 by the flow arrows H1 and H2, the solids exit the sections 74 and 76 via openings 42a and 42b, respectively, in the wall 42 and pass into the outlet compartment 50 where they mix before passing, via openings 15b in the lower portion of the wall 15, back into the furnace enclosure 12. The fluidizing air from all of the heat exchange sections 68, 70, 74 and 76 also flows into the furnace enclosure 12 through the openings 42a and 15b.
Feed water is introduced into, and circulated through, the flow circuit described above including the water wall tubes and the steam drum described above in a predetermined sequence to convert the water to steam and to superheat and reheat (if applicable) the steam.
During low loads, emergency shutdown conditions or start-up, a bypass operation is possible by terminating all air flow into the sections of the plenums 61 and 62 extending below the sections 68, 70, 74 and 76 and thus allowing the solids to build up in the inlet section 72a until their level reaches that of the weir port 80a in the partition 80, as shown in FIG. 5. Thus, the solids spill over into the section 72b of the inlet/bypass compartment 72 and fall down through the openings in the plates 54 and 60 and into the section 78. The solids thus build up in the section 78 until their level reaches that of the opening 42a in the wall 42 and enter the outlet compartment 50 before passing, via the opening 15b, back to the enclosure 12 at substantially the same temperature as when the solids entered the heat exchanger 38.
By selective control of the respective velocities of the air discharging into the heat exchange sections 68, 70, 74 and 76, the respective heat exchange with the fluid passing through the walls and partitions of the enclosure 40 can be precisely regulated and varied as needed. For example, in the bypass operation described above, instead of completely defluidizing the sections 68, 70, 74 and 76 and thus allowing all of the solids to bypass through the sections 72b and 78 as described above, the sections 68, 70, 72a, 74 and 76 can be partially fluidized so that only a portion of the solids bypass directly through the sections 72b and 78, and thus pass directly into the enclosure 12. The remaining portion of the solids would thus pass in the standard manner through one or more of the sections 68, 70, 74 and 76 to remove heat therefrom, as described above, resulting in less heat removal from the solids when compared to the standard operation described above in which all of the solids pass through the sections 68, 70, 74 and 76. Also, the fluidization could be varied so that the solids bypass one of the sections 68 and 70 as described in the bypass operation, above, and pass through the other as well as bypass one of the sections 74 and 76 and pass through the other. Moreover, during the standard operation, the fluidization, and the resulting heat removal, can be varied between the sections 68 and 70 and between the section 74 and 76, especially if these sections perform different functions (such as superheat, reheat, and the like). For example, the respective fluidization can be controlled so that 70% of the solids pass through the section 68 and 30% pass through the section 70 and so that 60% of the solids pass through the section 74 and 40% pass through the section 76, with these percentages being variable in accordance with particular design requirements.
In addition to providing the flexibility of operation discussed above, the present invention enjoys several other advantages. For example, a significant amount of heat can be removed from the solids circulating through the recycle heat exchanger 38 to maintain the desired temperature within the furnace for optimum fuel burn-up and emissions control. Also, the aforementioned selective fluidization, including the bypass modes, is done utilizing non-mechanical techniques. Moreover, the use of a pressurized system enables the separator to be relatively small, thus making room for the stacked heat exchange sections in the enclosure 40 to minimize the pressure vessel diameter.
It is understood that several variations can be made in the foregoing without departing from the scope of the invention. For example, an optional opening 15c can be provided in the wall 15a which permits the fluidizing air from all of the heat exchange sections 68, 70, 74 and 76 to be vented into the furnace enclosure instead of through the opening 15b with the solids. This venting of the air through the opening 15c would enable the air to enter the furnace at a higher level and function as secondary air. In this arrangement, the solids would still be returned to the enclosure 12 through the opening 15b but would be allowed to build up to a sufficient level to balance the pressure difference between the openings 15b and 15c. According to another arrangement, the openings 42c would be eliminated and an opening 15d would be provided in the lower portion of the well 15. As a result, the solids and the fluidizing air from the upper sections 68, 70, and 72 would be discharged through the opening 15d. The level of the solids in the section 78 would thus be sufficient to balance pressure, and the fluidizing air from the outlet compartment 50 would vent to the furnace through openings 15b (or 15c). With this arrangement, and especially the elimination of the opening 42c, the ability to bypass the lower sections 74 and 76 is eliminated and the amount of air returning to the lower furnace is reduced. Thus, this arrangement can be applied to designs that have economizer or steam generating tube coils in sections 74 and 76 which do not need the bypass capability for protection from overheating.
It is also understood that the number and location of the various other openings in the walls of the enclosures 12 and 40 can be varied, and more than one separator can be utilized. Further, although the present invention has been described in connection with a pressurized fluidized bed boiler, it is understood that it is equally applicable to an atmospheric fluidized bed boiler. Examples of the latter are fully disclosed in U.S. Pat. Nos. 5,133,943 and No. 5,140950, both assigned to the assignee of the present invention. Further, although a J-valve 32 was utilized in the preferred embodiment described above, it is understood that it could be replaced with another type of pressure sealing device within the scope of the invention. Examples of pressure sealing devices that would be applicable in this context are an L-valve, a seal pot, an N-valve or any other non-mechanical sealing device. Finally, although the preferred embodiment described above utilized two upper heat exchange sections 68 and 70 and two lower heat exchange sections 74 and 76, it is within the scope of the present invention to vary the number of these sections. Thus, in smaller systems one upper and/or lower heat exchange section can be used while larger systems may employ three or more.
Other variations in the present invention are contemplated and in some instances, some features of the invention can be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly in a manner consistent with the scope of the invention. | A fluidized bed combustion system and method in which a recycle heat exchanger is disposed integrally with the furnace of a fluidized bed combustor. The recycle heat exchanger includes a plurality of stacked sections for receiving the recycled solids and are arranged in such a manner that the recycled solids are introduced into an upper level of the sections and pass through these sections to a lower level of sections before returning to the furnace. A portion of the stacked sections contain heat exchange surfaces for removing heat from the solids therein while another portion does not. The solids in the various sections are selectively fluidized to control the flow of the solids through the sections to control the temperature of the solids accordingly. | 5 |
BACKGROUND OF THE INVENTION
It is known that α,α'-bis(t-butylperoxy) diisopropylbenzene having the formula: ##STR1## may be used as a crosslinking agent for a variety of polymers including low and high density polyethylene, ethylenepropylene copolymer, ethylene-propylene terpolymer rubber, natural rubber, butadiene-styrene rubber, polybutadiene, polyisoprene, polychloroprene, sulfochlorinated polyethylene, chlorinated polyethylene, silicone rubbers, and blends of these polymers or blends with other polymers. This peroxide is particularly effective as a crosslinking agent for ethylene-propylene terpolymer rubbers and blends of ethylene-propylene terpolymer rubbers with silicone rubbers.
While α,α'-bis(t-butylperoxy) diisopropylbenzene is an effective crosslinking agent for the polymers listed above, the resulting crosslinked product may be subject to blooming. Blooming is the migration to the surface of the cross-linked product of white, normally crystalline materials which causes nonuniform coloration in crosslinked articles, particularly in those which are dark colored due to the presence of fillers, pigments or dyes.
SUMMARY OF THE INVENTION
This invention is directed to a method for prevention of blooming in polymers crosslinked by α,α'-bis(t-butylperoxy) diisopropylbenzene. In particular, it is directed to novel compositions comprising a polymer crosslinkable by a peroxide, having incorporated therein a crosslinking amount of α,α'-bis(t-butylperoxy) diisopropylbenzene and an antiblooming agent, phthalic anhydride. It is further directed to compositions comprising a mixture of the peroxide crosslinker, α,α'-bis(t-butylperoxy) diisopropylbenzene, and the antiblooming agent, phthalic anhydride which mixture may be supported on an inorganic particulate carrier.
DETAILED DESCRIPTION OF THE INVENTION
This invention is concerned with a method of preventing undesirable blooming on the surface of articles prepared by crosslinking polymers with α,α'-bis(t-butylperoxy) diisopropylbenzene. This blooming is believed to be due principally to migration of crystalline bis(dimethylhydroxymethyl)benzene, a by-product of the crosslinking reaction, to the surface of the crosslinked article. In accordance with this invention, it has been discovered that when a quantity of phthalic anhydride at least approximately twice the stoichiometrical equivalent to the amount of peroxide present is included in the uncrosslinked composition, i.e., two moles of phthalic anhydride for each mole of peroxide, blooming does not occur in the crosslinked article. While not intending to be bound by any theory, it is thought that the phthalic anhydride reacts with the crystalline bis(dimethylhydroxymethyl)benzene during the crosslinking reaction, resulting in the formation of a material which is noncrystalline and which does not migrate to the surface of the crosslinked polymer.
U.S. Pat. No. 3,317,454 to Pedretti discloses the use of various materials as antiblooming agents to suppress blooming in ethylene copolymers which have been crosslinked with α,α'-bis(t-butylperoxy) diisopropylbenzene. Included among these materials are polyalcohols, polyalkylene oxides, and mixtures of polyalcohols with silicic acid, an alkylene glycol or polyalkylene oxide. There is, however, no teaching nor suggestion of the use of an anhydride to prevent blooming.
The peroxide employed in this invention is α,α'-bis-(t-butylperoxy) diisopropylbenzene. The meta or para isomers may be used, as well as mixtures of the two isomers. This peroxide is a very effective crosslinking agent for saturated and unsaturated hydrocarbon polymers. It is used at concentrations of about 0.1% to about 6%, preferably about 0.5% to about 3%, by weight based on the weight of the polymer, the quantity employed depending on the ease of crosslinking of the polymer being treated. This peroxide is effective at crosslinking temperatures of about 150° C. to about 200° C., preferably about 170° C. to about 180° C. The time of crosslinking may vary from a few seconds to several hours, depending on the temperature and the polymer employed.
As stated above, the peroxide may be used in the form of its para isomer, meta isomer, or mixture of the meta and para isomers. The peroxide may be used neat; as a solution in a suitable solvent; as a blend with a polymer or solubilizing resin; or as a concentrate deposited on an inorganic particulate carrier, clay and carbon black being preferred. If an inorganic particulate carrier is employed, it will constitute from about 50% to about 90% by weight, preferably about 50% to about 70% by weight, of the peroxide-carrier composition.
The crosslinkable polymers and polymer blends useful in this invention include ethylene-propylene terpolymer rubbers and blends of such rubbers with silicone rubbers (also known as polysiloxanes), which blends contain about 20% to about 100% by weight based on the weight of blend of ethylene-propylene terpolymer rubber. The eythylene-propylene terpolymer rubbers (also known as EPDM rubbers) are commercially available elastomeric copolymers containing about 40-70% ethylene units, up to about 5% of unconjugated diolefin units with the remainder being propylene units. The diolefinics normally employed are dicyclopentadiene, methylenenorbornene and 1,4-hexadiene.
This invention is particularly useful with polymer compositions containing dark colored dyes or fillers such as carbon black, iron oxide, lead chromate, and organic pigments since the undesirable blooming is more apparent on the surface of such dark colored materials.
The amount of phthalic anhydride needed to suppress blooming is about 2.0 to about 6.0, preferably about 3.0 to about 5.0 moles of anhydride per mole of peroxide employed, or, expressed on a weight basis, from about 88 to about 260, preferably from about 130 to about 220 parts by weight of anhydride per 100 parts by weight peroxide.
If desired, polyunsaturated curing coagents, such as trimethylolpropane trimethacrylate, which are employed to increase the level of crosslinking in peroxide-cured systems may be added to the crosslinkable composition. In addition, other additives normally present in polymer compositions, such as antioxidants, antiozonants, light stabilizers and plasticizers, may also be present, provided they do not interfere with the function of the peroxide.
The compositions of this invention may be prepared by any of the known methods for compounding additives with polymers or rubbers. Preferred methods are by use of a two roll mill or a Banbury mixer. Care should be exercised in keeping the mixing temperature below 120° C. so as to avoid decomposition of the peroxide during compounding.
EXAMPLE 1
The following formulations were prepared by blending on a two roll mill at a temperature of 60°-65° C. for 10 minutes.
______________________________________ Parts by WeightIngredients Formulation A Formulation B______________________________________EPDM Rubber (Vistalon2504, Enjay Co.) 100 100Zinc Oxide 5 5Age-Rite Resin D, 1.5 1.5R. T. Vanderbilt Co.(antioxidant)FEF Carbon Black 40 40Trimethyolpropane 1.5 1.5trimethacrylate curingcoagentα,α'-bis(t-butylperoxy) diiso- 3.8 3.8propylbenzene on claysupport(40% by weight peroxide;meta/para isomer ratioabout 2.0/1)Phthalic anhydride -- 1.33______________________________________
Both formulations were cured into sheets 0.075 inch thick by heating in a compression press for 20 minutes at 177° C. The sheets were stored at room temperature and blooming was observed as indicated below.
______________________________________ Formulation A Formulation B______________________________________After 2 days Slight NoneAfter 10 days Very much NoneAfter 30 days Very much None______________________________________
EXAMPLE 2
The following formulations were prepared by blending on a two roll mill at a temperature of 60°-65° C. for 10 minutes.
______________________________________ Parts by WeightIngredients Formulation C Formulation D______________________________________Blend of EPDM rubber 100 100(Nordel 1320, DuPont) andvinyl modified silicone rubber(SWS 727, SWS SiliconesCorp.(25% EPDM rubber, 75% vinylmodified silicone rubber)Magnesium oxide 5 5α,α'-(t-butylperoxy) diiso- 1.8 1.8propylbenzene on clay support(40% by weight peroxide;meta/para isomer ratioabout 2.0/1)Phthalic anhydride -- 0.6______________________________________
Both formulations were cured into sheets 0.075 inch thick by heating in a compression press for 15 minutes at 177° C. The sheets were stored at room temperature and blooming was observed as indicated below.
______________________________________ Formulation C Formulation D______________________________________After 5 days Slight NoneAfter 30 days Very much None______________________________________
EXAMPLE 3
Formulations the same as those shown in Example 1 were prepared according to the procedure in Example 1 except that the peroxide was used in unsupported form rather than supported on clay.
______________________________________ Parts by WeightIngredients Formulation E Formulation F______________________________________EPDM Rubber (Vistalon 100 1002504, Enjay Co.)Zinc Oxide 5 5Age-Rite Resin D, 1.5 1.5R. T. Vanderbilt Co.(antioxidant)FEF Carbon Black 40 40Trimethyolpropane 1.5 1.5trimethacrylate curingcoagentα,α'-bis(t-butylperoxy) diiso- 1.52 1.52propylbenzene (meta/paraisomer ratio about 2.0/1)Phthalic anhydride -- 1.33______________________________________
The formulations were cured as described in Example 2 and stored at room temperature. Bloom was observed as indicated below.
______________________________________ Formulation E Formulation F______________________________________After 2 days Slight NoneAfter 30 days Very much None______________________________________
EXAMPLE 4
The following formulations were prepared by blending on a two-roll mill at 60°-65° C. for 10 minutes.
______________________________________ Parts by WeightIngredients Formulation G Formulation H______________________________________EPDM Rubber (Minnesota 60 60Rubber Co. 557N M.B.)FEF Carbon Black 40 40Zinc Oxide 5 5α,α-bis(t-butylperoxy) diiso- 5.75 --propylbenzene on clay support(40% by weight peroxide;meta/para isomer ratioabout 2.0/1)Peroxide 40 NB -- 5.75(4 parts α,α'-bis(t-butylperoxy) diisopropylbenzene;2.5 parts Burgess KE clay;3.5 parts phthalic anhydride)______________________________________
Both formulations were cured into sheets 0.075 inch thick by heating in a compression press for 20 minutes at 177° C. The sheets were stored at room temperature and blooming was observed as indicated below.
______________________________________ Formulation G Formulation H______________________________________After 1 day Slight NoneAfter 4 days Moderate NoneAfter 5 days Moderate NoneAfter 8 days Very much NoneAfter 11 days Very much None______________________________________
EXAMPLE 5
The following formulations were prepared by blending on a two-roll mill at a temperature of 60°-65° C. for 10 minutes.
______________________________________ Parts by WeightIngredients Formulation I Formulation J______________________________________EPOM Rubber (Minnesota 60 60Rubber Co. 559N M.B.)FEF Carbon Black 40 40Zinc Oxide 5 5α,α'-bis(t-butylperoxy) 2.3 2.3para-diisopropylbenzenePhthalic anhydride 2.0 --______________________________________
The formulations were cured into sheets 0.075 inch thick by heating in a compression press for 15 minutes at 177° C. The sheets were stored at room temperature and blooming was observed as indicated below.
______________________________________ Formulation I Formulation J______________________________________After 1 day None NoneAfter 3 days None SlightAfter 7 days None ModerateAfter 11 days None Very much______________________________________
EXAMPLE 6
The following formulations were prepared as in Example 5:
______________________________________ Parts by WeightIngredients Formulation K Formulation L______________________________________EPDM Rubber (Minnesota 60 60Rubber Co. 559N M.B.)FEF Carbon Black 40 40Zinc Oxide 5 5α, α'-bis(t-butylperoxy) 2.3 2.3meta-diisopropylbenzenePhthalic anhydride 2.0 --______________________________________
The formulations were cured as in Example 5 and blooming was observed as indicated below.
______________________________________ Formulation K Formulation L______________________________________After 1 day None NoneAfter 3 days None ModerateAfter 7 days None ModerateAfter 11 days None Very much______________________________________
As indicated by Example 4, the peroxide and phthalic anhydride may be admixed prior to addition to the crosslinkable polymer. The amount of peroxide and phthalic anhydride used in the mixture will be the same as when they are added to the polymer separately, i.e., the quantity of phthalic anhydride is at least approximately twice the stoichiometric equivalent to the amount of peroxide used. The mixture may be deposited on an inorganic particulate carrier, clay and carbon black being preferred. When a carrier is used, it will generally comprise about 10% to about 50% by weight, preferably 20% to about 35% by weight, of the peroxide-phthalic anhydride-carrier composition. | Disclosed are nonblooming, crosslinkable compositions comprising crosslinkable elastomer, a peroxide crosslinker selected from α,α'-bis(t-butylperoxy) meta-diisopropylbenzene, α,α'-bis(t-butylperoxy) para-diisopropylbenzene and mixtures thereof, and phthalic anhydride. | 2 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 12/235,072 filed Sep. 22, 2008, the contents of which are incorporated by reference herein in their entirety, which is a continuation of U.S. patent application Ser. No. 11/087,905 filed Mar. 23, 2005, now U.S. Pat. No. 7,433,456, the contents of which are incorporated by reference herein in their entirety, which is a continuation of U.S. patent application Ser. No. 09/873,943 filed Jun. 4, 2001, now U.S. Pat. No. 6,914,970, the contents of which are incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to a system and method for a user to monitor and override a backup call receiving system or service to which an incoming telephone call intended for the user has been forwarded.
BACKGROUND
[0003] A call to a telephone user is sometimes forwarded to a service such as messaging service or assisting agent service. Such services are typically provided by a telephony service system external to the switch that serves the user's telephone line. Compared to a home answering machine, these service systems may be advantageous since they can provide more storage capacity and enable record tracking and post-call processing such as information redistribution.
[0004] Unlike the home answering machine, however, these service systems typically do not provide a way for the user to listen to the forwarded call while the interaction between the caller and the service system is in progress, e.g., while the caller is leaving a message with a messaging service system. Thus, the user cannot monitor and/or override the handling of the call like they would be able to do on a home answering machine. Yet, the user of the messaging service or assisting agent service often desires such monitoring and/or overriding of the service.
[0005] Some switch vendors provide a screening function from a serving switch which alerts the user about a call intercepted by a messaging or attendant system, and allows the user to screen the call. The cost of this switch function, however, is typically prohibitive. Another difficulty of the switch approach is that a switch operator cannot determine whether a call has been forwarded to a backup service system for which screening options are desired, or to another destination where such options are not desired. Moreover, most switches today do not include a call screening function and the call screening function is not available to users and/or call backup service providers served by such switches.
[0006] Thus, there is a need for an improved call monitoring and overriding system and method to handle the calls forwarded to a service system.
BRIEF SUMMARY
[0007] A system and method are disclosed for a user to monitor on a call-by-call basis a call forwarded to a system or service, such as a remote messaging system. In addition, the user may elect to override the service to which the call has been forwarded, i.e., to connect to the caller and disconnect the system service. Typically, the forwarded call was initially an incoming call from a calling party to the user and thereafter forwarded to a remote service system. Since the service system is remotely located, the user cannot otherwise screen the forwarded call as he or she could with a home answering machine. A monitoring and service system overriding function can be added as a component of the service system or it can be an independent subsystem used in conjunction with the service system.
[0008] Thus, after an incoming call is forwarded, the monitoring and service system overriding function determines a redirecting number of the user from which the incoming call was forwarded. The monitoring and service system overriding function then initiates a second call to the user and establishes a one-way voice path connecting the forwarded call to the second call. Thereafter, the user is notified, for example, with a distinct ring at the user's telephone, that the user may monitor the forwarded call via the established one-way voice path. The user may pick up the phone to do so, and may then choose to connect directly to the caller via a two-way voice path, and disconnect the forwarded call from the remote service.
[0009] Further aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a block diagram of an exemplary system for providing a monitoring and service system overriding feature according to the preferred embodiments.
[0011] FIG. 2 is a block diagram of an alternate system for providing the monitoring and service system overriding feature according to the preferred embodiments.
[0012] FIG. 3 is a state diagram illustrating the functionality of an application that provides the monitoring and service system overriding feature according to the preferred embodiments.
DETAILED DESCRIPTION
[0013] A call monitoring and service system overriding system is provided in a communication environment that allows a system user (“user”) to monitor and, at the user's option, connect to a call that has been forwarded to a remote service system. The remote service system may be, for example, a backup system such as a messaging system, an answering service, a third party's phone and a unified messaging system. For simplicity of description, the term telephone system is used herein where the term communication environment could also be used. Also, the term telephone line is used herein, where the term communication line could be otherwise used. The telephone line can be a line shared by telephone and data network access services, or can be another telephone line, or other lines, physically or logically separate.
[0014] FIG. 1 illustrates a communication environment, such as telephone system 100 . The telephone system 100 connects via telephone lines a calling party (“caller”) 110 to a called party, i.e., a user 120 of monitoring and overriding service. A serving switch 130 connects a calling party telephone line 125 to the called party's telephone line 123 to direct an incoming call from the caller 110 to the user 120 .
[0015] When the user's telephone is busy, the user does not otherwise answer the incoming call, or as set up by the user, the incoming call is forwarded to a remote service system 140 . Telephony trunks capable of conveying caller and redirecting numbers, such as Integrated Services Digital Network (ISDN) trunks, connect the serving switch 130 to the remote service system 140 . The remote service system 140 includes a message system, for example, voice-mail, and an answering service automatic call distribution system, such as when a call center agent answers the forwarded call and takes a message. Other types of remote service systems 140 could also be used, such as, automatically sending the call to a third party's phone, e.g., a colleague's phone, or sending the call to a unified messaging service. The unified messaging service is a service that allows for the storage and retrieval of message in various media formats and that, for example, converts an e-mail text message to a voice message or vice versa.
[0016] To provide for the monitoring and service system overriding service without a screening function included in the serving switch, a bridge and control component 150 is added to the remote service system 140 . The bridge and control component 150 determines if the called party of a given forwarded call has the monitoring and/or overriding service registered and activated. The bridge and control component 150 also alerts the user about the monitoring opportunity. The bridge and control component 150 bridges the user 120 into the monitoring session and can detect the user's intention to override the service system. If the user 120 indicates a desire to override the service system, the bridge and control component 150 sets up two-way voice path between the caller and the user and requests the serving switch 130 to directly connect the caller 110 and user 120 . The user 120 can signal his or her election to override the forwarded call by, for example, pressing a telephone key or speaking into the telephone handset.
[0017] FIG. 2 shows an alternate communication environment, such as telephone system 200 , that also uses the call monitoring and overriding service of the preferred embodiments. The caller 110 connects to the user 120 via the telephone system 200 . Telephone line 125 connects the caller 110 to the serving switch 130 and the serving switch 130 connects the caller 110 to the user 120 via the telephone line 123 . Unlike the configuration shown in FIG. 1 , the serving switch 130 is not directly connected to the remote service system 140 , but connects through a bridge and control subsystem 210 . The bridge and control subsystem 210 contains hardware, software, and data necessary to accomplish the monitoring and service system overriding functions of the forwarded call without modifying the original remote service system 140 . The bridge and control subsystem 210 functions similarly to the bridge and control component 150 in FIG. 1 .
[0018] FIG. 3 shows a state diagram illustrating an application 300 that enables call monitoring and service system overriding functions according to the preferred embodiments. It should be noted that this diagram depicts a state machine for a single user handled by the monitoring and service overriding function, but the function can simultaneously handle multiple independent users. The application 300 includes a program or process that resides on software, firmware or hardware, or combinations thereof. The application preferably resides with the bridging and control function as a subsystem 210 or as a component 150 in the remote service system 140 .
[0019] To utilize the monitoring and overriding service, the user 120 preferably registers via a registration procedure. The registration procedure records that the user desires the ability to monitor and override calls forwarded from their telephone line 123 . The user 120 preferably can also deregister from the monitoring and overriding service, and can activate or deactivate the service when registered. Various mechanisms can be used to register with or deregister (or activate or deactivate) from the monitoring and overriding service, including the user manually registering or deregistering with the service using a telephone. Other methods for registering and deregistering the user 120 could also be used, such as the user 120 using a world-wide web session to register with or deregister from the service.
[0020] Returning to FIG. 3 , at state 310 , the application 300 resides in an idle state before a call is forwarded to the remote service system 140 . At block 320 , the call arrives at the bridging and control subsystem 210 or component 150 with the condition that the called party is not registered as a monitoring service user 120 or the user has deactivated the monitoring service. In this case the service system interacts with the caller 110 normally, and the monitoring and overriding service is not invoked. The application 300 remains at the idle state (state 310 ).
[0021] In a preferred embodiment, to determine whether the called party is registered with the service and the service is activated, call-processing logic located at the bridging and control subsystem 210 or component 150 determines the called party's telephone number. For example, the call-processing logic can recognize a redirecting number in a call-setup-signaling message, which is the called party's telephone number. Thereafter, the called party's telephone number is compared with active registered users' telephone numbers to determine whether the called party is registered for the monitoring and overriding service.
[0022] At block 330 , a call arrives at the bridging and control subsystem 210 or the remote service system 140 and the called party is a registered and active user 120 . The application 300 initiates a second call to the user's telephone line 123 and connects the second call with the caller 110 via a one-way voice path. The one-way voice path allows the voice of the caller 110 to be audible to the user 120 without making the user's voice audible to the caller 110 . The user 120 can be notified of the second call with a distinct ring as directed by the application 300 and provided by the serving switch 130 . If the telephone line of user 120 is equipped with a caller identification (ID) device, the calling party's telephone information may appear as provided by the bridging and control subsystem 210 or component 150 .
[0023] At state 335 , the application 300 waits for a user interaction or for a timeout to occur while the caller 110 leaves a message with the remote service system 140 and the second call is being sent to the user 120 . At block 340 , when the user 120 fails to answer the second call before a determined time out period elapses or the caller 110 disconnects from the call, the application terminates the one-way voice path connection with the caller 110 and returns to the idle state (state 310 ).
[0024] At block 350 , the user 120 answers the second call upon receipt of the second call. Thereafter, the user 120 can listen to the forwarded call, e.g., the interaction between the caller 110 and the remote service system 140 via the one-way voice path. The voice path can be implemented by the bridge and control subsystem 210 or the bridge and control component 150 . Those skilled in the art with appreciate that that voice path can be implemented in other ways, such as with digital signaling processing and packet voice transmission and processing. At state 355 , the application 300 waits while the user 120 monitors the caller's call to the remote answering service 140 .
[0025] Upon listening to the caller 110 , the user 120 can elect to override the forwarded call or disconnect from the call. At block 360 , if the user 120 disconnects from the forwarded call or the caller interaction with the remote service system 140 ends, the application 300 terminates the one-way voice path and enters the idle state (state 310 ).
[0026] At block 370 , the user 120 elects to override the forwarded call. The user 120 can signal his or her election to override the forwarded call by, for example, pressing a telephone key or speaking into the telephone handset. The user may speak a command into the telephone handset or merely say anything, depending on how the application 300 is set up. The application 300 , upon detecting the pressed key or the user's voice, provides a two-way voice path between the user 120 and the caller 110 . The application 300 also preferably detaches the caller 110 from the remote service system 140 , for example, the recording or attendant leg of the forwarded call.
[0027] The bridge and control subsystem 210 or component 150 can request the serving switch 130 to bridge out the forwarded call and connect the caller 110 directly with the user 120 . At block 375 , the application 300 waits for the serving switch 130 to bridge out. At block 380 , when the serving switch 130 bridges out the forwarded call and connects the caller 110 directly with the user 120 , the application 300 can return to the idle state (state 310 ). The application 300 also returns to the idle state (state 310 ) if the caller 110 or the user 120 disconnects from the call before the bridging out occurs.
[0028] While the invention has been described above by reference to various embodiments, it will be understood that many changes and modifications can be made without departing from the scope of the invention. It is therefore intended that the foregoing detailed description be understood as an illustration of the presently preferred embodiments of the invention, and not as a definition of the invention. It is only the following claims, including all equivalents, which are intended to define the scope of this invention. | A system and method are disclosed for a user to monitor and/or override a forwarded call. Typically, the forwarded call was initially an incoming call from a caller to the user and thereafter forwarded to a remote service system, such as a remote messaging system. The system and method determine a redirecting number from which the incoming call was forwarded. The system and method then initiates a second call to the user and a voice path is established connecting the forwarded call to the second call. Thereafter, the user is notified, for example, with a distinct ring at the user's telephone, of the option that the user may monitor and override the forwarded call. The system and method can also execute procedures to actuate the options elected by the user. | 7 |
FIELD OF THE INVENTION
This invention relates to protective sheathes for tobacco pipes, cigar and cigarette holders and the like, and more particularly to a protective sheath which is adjustable to closely receive various size pipes and holders and which eliminates staining of the sheath interior itself.
BACKGROUND OF THE INVENTION
Since tobacco pipes, cigar and cigarette holders are held in the mouth during the burning of the tobacco, moisture from the mouth tends to penetrate the interior of the tobacco pipe and cigarette holder, and particularly the stem area in the immediate vicinity of the smoker's mouth. Conventionally, when the smoker terminates the smoking of tobacco, either in a pipe, cigar or cigarette holder form, the pipe or holder is simply inserted in the smoker's shirt or coat pocket. The liquid accumulating within the pipe or holder interior as well as the moisture from the mouth adhering to the external surface of the pipe stem or holder contacts immediately or by gravity movement seeps into the clothing of the smoker providing unsightly stains to the clothes which are additionally difficult to remove.
Attempts have been made to employ pouches, wrappings or similar implements as protective devices for the tobacco pipe, cigar or cigarette holder. Where the protective device envelopes the complete pipe including the bowl, they are of a size essentially determined by the size of the pipe in toto, are relatively bulky and while the protector itself prevents the staining of the clothing, the liquid accumulates within the interior of the protective device, rendering it unsightly and malodorous and making the tobacco smoker repugnant or reluctant to place the pipe or holder after use, back into a previously stained and wet protective device interior. Further, these devices have been manufactured in terms of given holder or tobacco pipe size and are not universally adapted for receiving various size pipes or cigar and cigarette holders.
It is, therefore, a primary object of the present invention to provide an improved tobacco pipe, cigar or cigarette holder sanitary protector which constitutes a complete unit, protects itself from external foreign matter and which insures a clean and dirt free receptacle for various size tobacco pipes, cigar and cigarette holders.
It is a further object of this invention to provide an improved sanitary protector particularly applicable to tobacco pipes and to accommodate most pipe stems in terms of conventional size and shape from straight to full bend.
It is a further object of the present invention to provide a pipe, cigar and cigarette holder sanitary protector of this type having an internal, removable and disposable absorbent material liner for easy replacement when soiled or at the smoker's discretion.
SUMMARY OF THE INVENTION
The invention is directed to a sanitary protective sheath assembly for a smoker's pipe, cigar, cigarette holder or the like, such protective sheath assembly comprising an elongated tubular sheath being closed at one end and open at the other to form a mouth for receiving the stem portion of the smoker's pipe or the like. A tubular absorbent liner sized to fit within the sheath and also being closed at one end is insertably received within the sheath interior retrievably coupled to a line coupled to the liner at one end and to the mouth of the sheath at the other, permitting the liner to be withdrawn after use. An adjustably sized closure band or strap surrounds the sheath adjacent the mouth for adjustably closing off the mouth about the upper end of a pipe stem adjacent the pipe holder to secure the sheath to the pipe. A closed cover pouch may be borne by the strap with a cylindrical plug carried internally of the pouch along with a replacement liner. The pouch is sized and is carried adjacent the bowl to one side of the sheath rendering it unobtrusive. Preferably, the strap bears a belt buckle and the strap carries holes to permit the strap to be buckled so as to close off the mouth of the sheath and to frictionally grip the pipe stem adjacent the pipe bowl, regardless of stem diameter variation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of the sanitary protective sheath assembly of the present invention forming one embodiment of the present invention and a smoker's pipe having its stem inserted within the same.
FIG. 2 is a side elevational view of the protective sheath assembly and the pipe of FIG. 1.
FIG. 3 is a bottom plan view of a portion of the assembly and pipe of FIGS. 1 and 2 showing the buckling of the strap carried by the sheath.
FIG. 4 is a longitudinal sectional view of the assembly and pipe of FIG. 2 taken about line 4--4.
FIG. 5 is a transverse sectional view of the assembly and pipe of FIG. 2 taken about line 5--5.
FIG. 6 is a side elevational view of a portion of the protective sheath assembly of the present invention with the pipe removed and the plug inserted within the mouth of the protective sheath.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, there is shown in the figures a tobacco pipe, cigar and cigarette holder sanitary protector assembly indicated generally at 10, as applied to a tobacco pipe, indicated generally at 12, of conventional construction and configuration. The pipe 12 is comprised of two basic parts, a stem indicated generally at 14 and a bowl 16; the stem 14 in this case being arbitrarily designated as the portion of the pipe 12 acting as an extension to the bowl 16 and being generally at right angles to the axis of that bowl. Thus, the stem 14 includes insofar as this description is concerned, or an inner stem section 14a and an outer stem section 14b which may in fact be mechanically joined for separation as by way of separation line 14c. The outer section 14b remote from the bowl 16 terminates in a flat tip 14b. It is from the tip 14d that the majority of liquid seepage occurs, when the pipe is stored in vertically upright position, as shown in FIGS. 1, 2 and 4, within the sanitary protective sheath assembly 10, normally with the pipe (or alternatively a cigarette or cigar holder) being inserted within the breast pocket of the shirt or coat of the smoker.
Turning to the sanitary protective sheath assembly 10, it in turn is comprised of major elements including an elongated tubular sheath or cover indicated generally at 18, a tubular absorbent liner 20 insertably carried within the sheath 18, an adjustably sized strap or band indicated generally at 22 supported adjacent the open end of sheath end and an auxiliary pouch 24 carried by the strap 22 and thus supported on the exterior of the sheath 18.
The sheath or cover 18 preferably comprises a molded product consisting of a round, open at one end and closed at the other, cylindrical tube, and provided with diametrically opposed loops 32 adjacent the open end as defined by lip or bead 30, lip 30 defining a mouth M for reception of the pipe stem 14. The sheath 18 is preferably formed of a non-porous material such as rubber, being provided with the flexibility needed to accommodate the inserted tobacco pipe, cigar or cigarette holder and permitting the wall of the sheath to be compressed radially to frictionally fit the sheath to the stem 14 of the pipe. The annular wall of the sheath 18 is of ample thickness to give support to and assist the strap 22 to provide a firm liquid seal about the circumference of the pipe stem 14 during use. The lower end 28 of the sheath 18 is rounded and closed, while its opposite end is open as provided by lip or bead 30. The bead or lip 30 additionally serves the purpose to firmly hold a connector 56, FIG. 4, associated with the removable absorbent liner 20. The molded tubular resilient sheath 18 may have integrally molded, diametrically opposed loops 32 adjacent the mouth M which extends parallel to the axis of the sheath, the loops 32 receiving the narrow elasticized fabric band or strap 22 which strap or band in turn supports the pouch 24 of the assembly. The elasticized fabric band 22 constitutes a flexible fastening and contains spaced eyelets or holes 38 adjacent one end 40 of the strap, the opposite end bearing a buckle 34 which buckle is provided with a pivotable finger 36 which projects through a given eyelet or hole 38, thus reducing the diameter of the circular loop defined by the band 22 and causing the sheath to be compressed radially about stem 14 of the pipe.
A cylindrical device is thus frictionally held within the sheath 18, that device may be a smoker's appliance such as the tobacco pipe 12 shown, alternatively a cigar or cigarette holder as indicated previously as well as a cylindrical protective plug 26 which includes an enlarged diameter portion 26a at one end of a size corresponding to rim 30 and seating on the rim 30, when inserted, FIG. 6, and buckled into frictional contact by the utilization of the strap or band 22. The width of the band or strap 22 is generally equal to the axial length of the plug 26.
The pouch 24 is manufactured of the same material as the sheath 18 or alternatively may be a different material which could be leather, plastic, cloth, canvas, and in size sufficient to accommodate not only the plug 24 but also a spare absorbent liner as at 20', FIG. 2, and additional elements may be carried therein such as a pipe smoker's wire, etc. The pouch 24 is also of tubular construction and includes integrally a flap 44 constituting a cover for the open end of the pipe and the pouch proper being provided with snap connectors or fitting members 48 and 50 respectively to snap the cover and maintain it in closed position except when access is required for either the plug 26 or the spare liner 20'. Preferably, a loop as at 46 is carried by the pouch 24, the loop being sized similar to loops 32 and receiving the strap or band 22, thus maintaining the pouch on the strap or band and the band or strap on the sheath at all times. The buckle simply adjusts the frictional force and gripping capability of the sheath with respect to the inserted pipe stem 14. The material for the loop 46 may be leather or plastic or the like.
The protector plug 26 may be formed of leather, rubber or plastic and is solid. The enlarged diameter portion or rim 26a permits it to be inserted to the extent of lip 30 of sleeve 18 and tightening of the belt of the band or strap 22 effects the closure of the sheath absent the pipe 12, FIG. 6, as shown. In order to prevent loss of the plug 26, the plug itself may be coupled to the pouch by a suitable tether which could be formed of waxed twine, plastic or fisherman's line of a length sufficient to permit the plug to be fully inserted within the interior of the pouch 24, one end of the tether to the pouch cover 44 and the other to the plug on the end carrying rim 26a.
The absorbent liner indicated generally at 20 is soft, pliable and absorbent, may constitute a paper material and is thus able to conform to the shape of the device such as the pipe stem 14 inserted therein. Preferably, the absorbent liner material is chemically treated so as to be both safe to the user and to improve or at least not diminish absorbing capability. The liner is in tubular form, being closed at its lower end 20a and open at its upper end 20b. Further, the length of the liner is somewhat shorter than that of the sheath 18, partially because the liquid is in the vicinity of the tip 14d of the pipe stem 14. In this respect, upon insertion of the liner 20, it is required that it be easily removed from the sheath 18. In that respect, a small C-shaped metal clip 50 attaches to the open end 20b of the liner 20 and one end of a pull line 52 is connected thereto while the opposite end bears the connector 56 which is of U-shaped configuration and simply snaps to the bead or rim 30 of sheath 18. The length of the line 52 is essentially the difference between the axial length of the liner and that of the sheath. The connector 56 is preferably formed of spring steel and shaped to fit over the lip 30 of the sheath. It acts as a retreiver along with line 52 for the liner 20 and also constitues a preventive measure against the liner 20 accidentally dropping out of the sheath or cover 18. This prevents not only the liner from being lost but also from being soiled. The pull or retrieving line 52 may comprise waxed twine, a strip of leather cloth or a plastic cord. The clip 54 is provided with a prong which projects through the absorbent liner 20 and mechanically locks the pull line at its lower end to the upper end 20b of the liner 20.
The sanitary protective sheath assembly for a smoker's pipe or the like from the description may be seen to function quite capably in absorbing moisture and sedimentation emitted through the mouthpiece, thereby keeping the external areas of the mouthpiece dry while the sheath restricts the moisture from the mouthpiece to the interior wall of the sheath, thus forming a very safe carrier for the smoker's appliance and eliminating all possibility of soiling clothing or other wearing apparel such as jackets, trousers, shirt pockets or other clothing or articles within which the pipe may be carried and make contact such as in drawings and suitcases. Additionally, the sheath maintains the inserted mouthpiece of the smoker's appliance completely free and safe from the possibility of contact with any external liquid or from entering the interior thereof as well as other external foreign matter such as dust particles and the like. Further, by use of the plug 26 the cigar and cigarette holder may be carried by the sheath with the plug in place keeping the holder protected from external liquids, dirt, dust and other matter. This is also possible with respect to a pipe stem.
While the invention has been particularly shown and described with reference to a preferred embodiment 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 spirit and scope of the invention. | A tubular, open ended elongated liquid impervious sheath bears internally, a removable tubular absorbent material liner. A buckled strap borne by the sheath adjacent its mouth permits the sheath to be frictionally clamped to the pipe stem adjacent the bowl ensuring retention of the stem within the lining which absorbs any liquid. The strap bears a pouch holding a cylindrical plug employed in closing off the sheath absent a pipe, and a replacement liner. | 0 |
BACKGROUND OF THE INVENTION
This invention is concerned with economically converting low BTU gas to high BTU gas. More particularly, methane is produced by reacting carbon monoxide separated from purified low BTU gas with hydrogen produced by the steam-iron process using the deoxidizing properties of the low BTU gas. This also removes nitrogen from the final product.
This disclosure relates to a process for producing methane from a low BTU gas containing hydrogen, carbon monoxide, nitrogen and relatively small amounts of the other materials found in the gas produced by the gasification of carbonaceous materials with air. This gaseous product is sometimes called producer gas. By way of example, a producer gas produced from the gasification of coal with air may contain on a dry basis 15% hydrogen, 29% carbon monoxide, 50% nitrogen, 5% carbon dioxide and 1% methane.
The shortage of natural gas, which is predominantly methane, has greatly increased the need for economic production of synthetic natural gas. Gasification of carbonaceous materials, for example coal, produces a low BTU gas generally having a fuel value below 300 BTU/std. ft 3 which is too low for most natural gas uses. Methane has a heat of combustion of 1013 BTU/ft 3 . A large number of processes have been proposed for enhancing the heat value of low BTU gases. Many of these processes produce what is called an intermediate BTU gas because the final product is diluted with low heat value gases. Low BTU gases lack sufficient hydrogen. The economics of converting low BTU gases to methane is affected by the cost of hydrogen and process steps required to produce a good quality methane gas. This is affected by the purity of the various reaction streams and final product.
Accordingly, it is an object of this invention to provide a method of producing a high BTU product in a way that effectively uses the carbon monoxide in the feed gas and the remaining low BTU gas to reduce the cost of producing hydrogen in a way that produces a final pipeline product that requires no further treatment other than water removal.
SUMMARY OF THE INVENTION
A low BTU feed gas comprised predominantly of carbon monoxide, hydrogen and nitrogen is processed to produce a high BTU methane-rich gas. The feed gas is divided into two streams. One stream is passed to the reducing stage of an iron-steam generation process. The other stream is treated to removed carbon monoxide which is used as one of the reactants in a CO--H 2 methanator. After CO removal the remaining H 2 --N 2 feed gas is also passed to the iron oxide reduction unit. Nitrogen, the major undesirable diluent, is removed at the hydrogen production stage of the process. Hydrogen produced in the iron oxidation stage of the process is used as the other reactant in the methanator. Water produced in the methanator is easily removed. This process, therefore, produces a methane product suitable for use as natural gas in few steps with efficient use of the unreacted part of the low BTU feed gas and with efficient nitrogen removal. When present, undesirable impurities and diluents like hydrogen sulfide, and carbon dioxide may be removed first.
BRIEF DESCRIPTION OF THE DRAWING
The drawing is a schematic representation of a process for converting low BTU gas to high BTU gas with impurity and partial carbon monoxide separation and with efficient utilization of the remaining feed gas.
DETAILED DESCRIPTION
The following description is concerned with a particular sequence of known process stages to economically produce high BTU gas from low BTU gas comprised predominantly of CO, H 2 and N 2 . Since low BTU gases derived from coal and some other carbonaceous fuels contain H 2 S and CO 2 , the process hereinafter described in detail will also allow for the presence of these unwanted materials. Accordingly as shown in the drawing, a low BTU feed gas comprised of CO, CO 2 , H 2 S, H 2 and N 2 in line 11 is passedthrough impurity removal zone 13 where acid gases and other impurities are removed from the feed gas without significant removal of carbon monoxide and hydrogen in the feed gas. Otherwise, any conventional H 2 S and CO 2 removal process may be used. For example, absorption, chemical conversion, or a combination thereof, with di- or mono-ethanolamine, hot potassium carbonate, propylene carbonate, tetrahydrothiophene dioxide and alkanolamine, or polyglycol-ether.
After acid gas removal, the remaining feed gas is divided into two streams. One stream is passed through line 15 to carbon monoxide removal and recovery zone 17 where carbon monoxide is separated from the feed gas to produce a CO-rich stream in exit line 21 and an H 2 --N 2 -rich stream in exit line 25. Any suitable conventional process may be used for separating the carbon monoxide from the low BTU feed gas. Cryogenic cooling or physical absorption with copper ammonium acetate or cuprous aluminum chloride solutions in an absorption column may be employed. Generally, absorption is carried out at temperatures below 100° F. and pressures between 50 to 60 atmospheres. After absorption, heating (for example to 170° F.) and changing the pressure (for example, 50 or more atmospheres) of the copper liquor releases a relatively high quality carbon monoxide. After the desorption step, the resulting CO-rich stream in line 21 is passed to methanation zone 23.
As shown, the other stream of feed gas bypasses the CO-removal and recovery zone through bypass line 19 where it is combined with the H 2 --N 2 -rich stream in line 25 and is passed into iron oxide reduction unit 27. In the iron reduction unit, these combined streams react with particles of iron oxides fed into the unit through line 29. The reducing reaction may be conducted at atmospheric pressure or any desired higher pressure. For the process of this invention it is preferred that iron oxide be reduced to free metal without the formation of iron carbides or free carbon. The preferred reactions are as follows:
Fe.sub.3 O.sub.4 +4CO→3Fe+4CO.sub.2 (1)
FeO+CO→Fe+CO.sub.2 (2)
The hydrogen in the combined streams is also effective in reducing iron oxides to iron. This provides better balance between the hydrogen produced in a subsequent iron oxidation unit and the carbon monoxide previously separated and passed to the methanation zone. Moreover, in the oxidizing unit, carbides and carbon would react to form methane and the oxides of carbon. These oxides would need to be removed. Higher temperatures, for example 1100° F. and above, favor the formation of free iron and carbon dioxide in the reducing unit while lower temperatures like 850° F. to 1000° F. favor carbide and carbon formation.
In the reducing unit, the iron oxide particles, for example 20 mesh and smaller, and reducing gas are reacted preferably at a temperature of between 1100° F. and 1650° F. for sufficient time to reduce the iron oxides to free iron and lower oxides. These reactions except for the reduction of oxides with hydrogen are exothermic and require no additional heat. The upper part of the reduction unit is usually hotter than the lower part. For illustrative purposes, the reduction unit is shown as a continuous flow system, but a batch system may be used. The reducing feed gas passes upward through iron oxide solids and the spent feed gas which is predominantly nitrogen and carbon dioxide is removed overhead through vent line 31.
The reduced iron and iron oxide exits the reduction unit through line 33 and is passed into iron oxidizing unit 35 where it is reacted with steam introduced into the bottom of the oxidizing unit through steam inlet line 37. In this unit, the reduced iron oxide and free iron react with steam to form higher oxides of iron and hydrogen in accordance with the following reactions:
Fe+H.sub.2 O→FeO+H.sub.2 (3)
3FeO+H.sub.2 O→Fe.sub.3 O.sub.4 +H.sub.2 (4)
Other reactions will occur. For example, some CO 2 carried over with reduced iron particles from the reduction unit may react with free iron to form iron oxide and carbon monoxide as follows:
Fe+CO.sub.2 →FeO+CO (5)
The carbon monoxide may then react with free iron and hydrogen or with hydrogen to form methane and iron oxide as follows:
Fe+CO+2H.sub.2 →CH.sub.4 +FeO (6)
2H.sub.2 +2CO→CH.sub.4 +CO.sub.2 (7)
By the same token, the carbon dioxide may react with free iron and hydrogen to methane and iron oxide as follows:
2Fe+CO.sub.2 +2→CH.sub.4 +2FeO (8)
Reactions 3, 4, 6, 7 and 8 are exothermic. This plus the low cost of iron illustrates the special utility of using iron to produce hydrogen. The hydrogen is removed overhead through line 39 where it is passed through dryer 41 to remove water through line 43. The dried hydrogen is then passed through line 45 to be combined with the carbon monoxide in Line 21 in the appropriate H 2 /CO ratio, for example 3.0, for reaction in methanation zone 23 to produce CH 4 -rich product gas in line 47. Generally, it will be unnecessary to purify the hydrogen gas of other gases before introduction into the methanation zone.
In the methanation zone, therefore, a high BTU single product methane gas and water is produced in product line 47. The water is readily removed. Any conventional single or multiple stage process for forming methane from carbon monoxide and hydrogen may be used. In this process, since the reactants are of high quality and in the appropriate ratio, methane may readily be formed in one stage. Multiple beds may be used for temperature control. As used herein, methanation is a catalytic reaction between carbon monoxide and hydrogen to produce methane according to the following equation:
CO→3H.sub.2 →CH.sub.4 +H.sub.2 O+heat (1)
Much has been written on this process. The process is typically carried out by passing the gaseous reactants through a bed of catalyst, for example, nickel or nickel alloyed with platinum, or by fluidizing the catalyst at temperatures between 600° and 1300° F. and at pressures above 200 psig. Space velocities vary over a wide range, for example, between 1800 and 12,000 v/v/hr.
EXAMPLE
A low BTU feed gas is processed in accordance with the process of this invention with initial CO 2 removal zone 13 with the results shown in Table 1.
TABLE 1______________________________________Line Moles Mole PercentNo. Per Hr. N.sub.2 CO CO.sub.2 H.sub.2 CH.sub.4 H.sub.2 O______________________________________11 46.8 46.8 17.5 13.0 21.0 1.7 --15 87.65 53.4 20.0 0.7 24.0 1.9 --21 7.38 -- 100 -- -- -- --25 80.27 58.3 12.6 0.8 26.2 2.1 --31 80.27 58.3 3.7 9.8 7.5 2.1 --37 80.01 -- -- -- -- -- 10039 80.01 -- -- -- 28.6 -- 71.445 22.86 -- -- -- 100 -- --47 15.92 -- 0.002 1.4 10.0 45.0 43.6______________________________________
After removing the water, the final pipeline gas is 79.7 mol percent methane, 17.8 mol percent hydrogen, 2.4 mol percent carbon dioxide, and 0.003 mol percent carbon monoxide.
Reasonable variations and modifications are practical within the scope of this disclosure without departing from the spirit and scope of the appended claims. | Low BTU feed gas formed by gasification of carbonaceous materials with air is converted to high BTU gas by partial carbon monoxide separation and by using the reducing characteristic of the remaining feed gas in the iron reduction unit of a standard iron-steam process for manufacturing hydrogen. The hydrogen manufacturing stage also removes nitrogen which is a primary cause of low heat value in upgraded gases. The separated CO and the manufactured H 2 are converted to a high quality methane. In the process, other undesirable impurities and diluents like hydrogen sulfide and carbon dioxide may be removed first. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to the art of powder metallurgy and, more particularly, it relates to dispersion strengthened metals. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).
Certain metals may be strengthened by adding to them relatively small quantities of particular materials in such a manner that the added materials do not mix with the metal to form a homogeneous phase, but are uniformly dispersed in particulate form throughout the metal. The material which is added may be referred to as a dispersoid, while the metal it is dispersed in is referred to as the matrix metal; the combination is known as dispersion-strengthened metal. Oxides make good dispersoids because of their high hardness, stability at high temperatures, insolubility in matrix metals, and availability in fine particulate form.
The present invention is dispersion strengthened copper, where the dispersed particles are of copper oxide or copper having a coating of copper oxide. A unique aspect of strengthening copper by means of a dispersed phase, in contrast with the conventional methods of solid solution hardening or precipitation hardening, is that a significant increase in strength is available while retaining a substantially pure metal matrix with very little or virtually no alloying element remaining in solid solution. This has the advantage of giving markedly higher strength without significant loss in electrical or thermal conductivity or in corrosion resistance.
Copper which is dispersion-strengthened with aluminum oxide is commercially available. Prior to the present invention, the use of copper oxide as a dispersoid in copper was unknown.
Additional information may be found in "DispersionStrengthened Materials," 7 Powder Metallurgy, 9th Ed., Metals Handbook, American Society for Metals, 710-727 (1984)
SUMMARY OF THE INVENTION
This invention is a composition of matter comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide, and a method for making this composition of matter.
The method comprises oxidizing at least a portion of copper which is in the form of a powder to form particles, each particle consisting of copper having a thin film of copper oxide on its surface; consolidating said powder and particles to form a workpiece; and exposing said workpiece to microwave radiation in an inert atmosphere until a surface of said workpiece reaches a temperature of at least 500° C.
It is an object of this invention to provide dispersion-strengthened copper in which the dispersoid is copper oxide and a process for making said copper.
It is also an object of this invention to provide a dispersion-strengthening process for copper in which less energy is required in comparison to conventional processes.
It is also an object of this invention to provide a copper dispersion-strengthening process which is less complex and can be accomplished in a shorter time than prior art processes.
It is a further object of this invention to provide a copper dispersion-strengthening process which can be accomplished in an inert gas atmosphere rather than a hydrogen atmosphere.
DETAILED DESCRIPTION OF THE INVENTION
Pure copper powder having a nominal particle size of 1 micron was obtained from Sherritt-Gordon Mines, Ltd. In experimentation on the present invention, copper powder was exposed to the atmosphere in order to form a very thin copper oxide film on at least a portion of the copper particles of the powder. Air penetrates the mass of powder, so that a copper oxide film forms on at least a portion of the particles located in the interior of the mass as well as the exterior. After oxidation, the particles were consolidated into a 1 in. diameter by 1 in. long (2.5 cm×2.5 cm) cylinder by pressing atmospheric temperature and a pressure of 10,000 psi (68.9 MPa). A binder substance to aid in consolidation was not required. The cold pressed workpiece was then placed in a plastic pressing sack and isostatically pressed at atmospheric temperature and 50,000 psi slightly less than (344.7 MPa), thereby forming a workpiece having a diameter of 1 in. 2.54 cm) and a length of slightly less than one in. (2.5 cm). The density of the workpiece after isostatic pressing was 4.8 g/cm 3 .
The workpiece was placed in a low density alumina holder which is transparent to microwaves and has a 1/8 in. (0.3175 cm) diameter aperture, so that the temperature of the workpiece could be determined by means of an infrared optical pyrometer. The holder was placed in a Litton Model 1521 microwave oven and exposed to microwaves at a frequency of 2.45 GHz. The oven was operated at its maximum power of 700 W. During microwaving, an argon-rich atmosphere was maintained within the oven. Though large pieces of copper are opaque to microwaves, fine copper particles couple with 100% of incident microwave radiation. The oxides, cuprous oxide and cupric oxide, couple only partially with microwave radiation at room temperature. However, the copper oxide film has the effect of increasing the effective half power depth of penetration of the composite copper/copper oxide system by the electromagnetic field, resulting in more efficient coupling of the workpiece to the microwave radiation.
The workpiece was microwaved for 35 minutes, reaching a surface temperature of about 650° C. It was held at this temperature for 1 minute and then allowed to cool. The workpiece was cut and polished; the polished surface appeared as an extremely fine grain copper structure with uniform dispersion of very fine particles which, it is believed, were of copper oxide and copper coated with copper oxide. There was a small amount of copper oxide located at the grain boundaries. The microstructure was that of dispersion-strengthened copper. The density of the workpiece was 6.2 g/cm 3 . Another workpiece was prepared in the same manner and had a density of 6.8 g/cm 3 .
The electrical resistivities of several workpieces prepared in a similar manner were measured. The resistivities of pressed workpieces before microwaving ranged from about 10 6 to about 10 8 ohm-cm. After microwaving, the room temperature resistivities ranged from about 0.01 to about 1 ohm-cm. The oxygen content of the workpieces was from less than 1 to about 10 wt %.
Two different workpieces were tested for strength and hardness; the results are shown in the Table. The Brinnell hardness was determined using a 500 kg load. The Rockwell hardness is based on the E scale.
TABLE______________________________________ Ultimate Modulus of Compressive Rockwell BrinnellSample Elasticity Strength Hardness Hardness______________________________________1 12,580,000 psi 25,159 psi 70 62 (86,726 MPa) (173.4 MPa)2 21,220,000 psi 52,640 psi 57 55 (146,290 MPa) (362.9 MPa)______________________________________
It is expected that the temperature of a workpiece should be raised to at least 500° C. in the practice of this invention and it may be raised to just under the melting point of copper. It may be necessary to use a holding period, at 500° C. or above, of from about 1 minute to about 2 hours. The sizes of the particles dispersed in the workpieces were quite small and ranged up to about 5 microns. Consolidation of the powder after oxidation can be accomplished by means other than pressing, such as plasma spraying or extruding. The pressure applied in consolidating a workpiece may range from about 10,000 to about 70,000 psi (68.9-482.6 MPa).
It is expected that the particle sizes of copper powder used as a starting material may range from less than 1 micron up to about 5 or even to 10 microns. Particle sizes mentioned herein are as determined by a Fisher Sub-sieve Sier. Powder may be defined as consisting of particulate material of small size. It is expected that the microwave radiation used in the practice of this invention will have a frequency of from about 500 MHz to about 500 GHz and be supplied at a power level of from about 50 W to about 1 MW.
As mentioned above, there was copper oxide at the grain boundaries, between the grains, of the workpieces which were cut and polished. The references herein to particles and particulate matter herein are intended to include such copper oxide at the grain boundaries.
In the practice of the present invention, it is believed that it is crucial to condition the surface of at least a portion of the particles of the copper powder. In general, metals, such as copper, are opaque to microwave radiation and will not be heated when subjected to microwaves. However, a metal particle of a sufficiently small size will couple to microwaves and be heated. A particle of sufficiently small size to couple will have a diameter less than or equal to the skin depth for a particular wave length of incident radiation. The depth of penetration of microwave radiation (skin depth) can be calculated from the frequency of the radiation, the magnetic permeability of the metal, and the electrical conductivity of the metal. In the present case, the depth of penetration is about 1.4 microns; thus, a copper particle having at least one dimension less than 1.4 microns can be heated by microwaves.
However, a mass of powder, even if it has particles of sizes less than 1.4 microns, will behave as a solid when subjected to microwave radiation. But, if the surfaces of the metal particles are conditioned by coating a surface with a substance which is transparent to microwave radiation, the particles will couple. In the present case, the thin films of copper oxide on at least a portion of the particles of copper powder is substantially transparent and, therefore, facilitates electronic heating of the copper particles. Copper oxide usually consists of cuprous oxide and cupric oxide. These do not couple well with microwave radiation at room temperature, given the low electric field intensity in the microwave oven used in this experimentation, but require much higher temperature before being capable of heating by microwave. For an oven with a higher electric field intensity, they would couple well at low temperatures. The amount of coupling with microwave radiation increases greatly at a temperature of about 500° C. for cuprous oxide and about 600° C. for cupric oxide. Thus, in the practice of the present invention, when heating a workpiece to high temperatures, the copper oxide is heated electronically.
It is emphasized that the present invention does not employ a coupling agent, which is a substance capable of electronic heating. When a coupling agent is used, the agent is heated by microwaves and the heat then flows to another substance not susceptible to microwaves by conduction and, perhaps, convection.
It is expected that the use of microwave radiation to heat substances which are normally opaque to microwaves by conditioning the surfaces of particles of the substances will be useful in numerous applications in addition to the present invention.
The foregoing description of invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is intended that the scope of the invention be defined by the claims appended hereto. | A composition of matter comprised of copper and particles which are dispersed throughout the copper, where the particles are comprised of copper oxide and copper having a coating of copper oxide, and a method for making this composition of matter. | 2 |
FIELD OF THE INVENTION
[0001] The present invention generally relates to agricultural equipment and machines, particularly, cotton harvesting machines (cotton pickers); and, more particularly, to cotton picker systems and apparatus for detecting overloads, overruns, or slow downs, at the picking drum.
BACKGROUND OF THE PRIOR ART
[0002] In conventional cotton pickers, for each row of cotton to be picked, there is provided a picker drum, which supports at least one vertical rotor assembly, which assembly consists of a plurality of radially extending, cotton-picking spindles. Each rotor, and its associated drive gears, are protected against damage by a slip clutch, which removes drive from the rotor when an overload occurs, e.g. when debris becomes lodged in the drum. That is, a rotor shaft extends downwardly through the slippable portion, or inner hub, at the center of the slip clutch, and then through the drum. The rotor drive gear is mounted to the external, driven portion, i.e. housing, of the slip clutch. As the slip clutch is driven by a conventional power source, via the drive gear, the rotor also rotates on its vertical axis, in tandem with the clutch.
[0003] During the overloaded condition, ratcheting or clicking sounds are generated as the cams and lobes on the drive and driven portions, of the gear train and clutch respectively, slip past each other. Absent a slippage detection system, an operator, seated in the cab of the cotton picker, must rely upon hearing the slipping sounds. However, he may not immediately hear the sounds because cabs tend to isolate the operator from the noise of the picker unit. This inability to immediately recognize the overload condition can result in damage to the drum and its drive, as well as reduced productivity from the loss of cotton.
[0004] Before now, the slippage detection systems measured the speed differential between the rotor assemblies of the picking drums. The drum rotor assembly normally comprises two rotor shafts per picking drum. Each rotor shaft of each drum, has a speed sensor, therefore there are 12 sensors on a 6 row machine. Each sensor measures the revolutions per minute (RPM) from its respective shaft and sends the signal to a computer processing unit that calculates the speed differential between the two shafts. A microprocessor captures the speed differential at each rotor assembly and the resulting average differential speed after comparing all six assemblies. The processor sends a fault warning if any rotor speed and/or speed differential deviates from the average by more than ±10′.
[0005] There are many factors influencing this fault warning. Typically, the shaft must spin a minimum number of RPMs before the computer processing unit can detect any degree of change. Most computer processors need a certain minimum number of cycles and time to process and validate signals from the speed sensor. Since damage continues to occur, during at least that minimum number of cycles, and during the processor cycle validation time, the delayed detection or late warning of the slippage leads to, inter alia, aggravation of the deterioration of various fine-tuned components of the harvester machines.
[0006] Identifying and repairing the damage to these fine-tuned components may exceed the troubleshooting capabilities of the average operator.
SUMMARY OF THE INVENTION
[0007] In a cotton-picking unit of a cotton harvester, or in other agricultural or construction equipment or in machine tools there can be an overrunning clutch having an input driven by rotable power and an output driven by the individual unit. The input and output are engaged such that the input and output are rotable relative to one another along the path of rotational movement when in an overrunning condition. The invention comprises negating the need for a complicated algorithm or use of a microprocessor unit to detect such overrunning condition, and generally comprises the following components of a non-contact detection system:
(a) a sensor operable in a first state when a predetermined magnetic field is absent, and operable in a second state when the predetermined magnetic field is present; and (b) a magnetic actuator mounted and operable for emitting the predetermined magnetic field; and (c) a shield disposed on the input or the output in a position for shielding the sensor from the actuator when the input and the output are jointly rotating in the normal condition, and such that when the input and the output are in the overrunning condition the shield will be at least intermittently positioned to expose the sensor to the magnetic field and to change the state of the sensor.
[0011] A principal aspect of the present invention employs a magnetic reed switching system having three components, i.e. an actuator magnet, a magnetic reed switch sensor, and a metallic shield therebetween. The state of the switch, i.e. “open” or “closed” changes by shielding or unshielding the magnetic flux between the sensor and the magnet.
[0012] In this invention, each rotor slippage can be detected independently, without the need for comparing average speed differentials to that of its neighboring rotor. Error due to speed averaging is avoided.
[0013] In yet another aspect of the invention, a strong slippage signal can be created without computer processing. Thus, the cost of this control system is only a fraction of the cost of prior art systems.
[0014] Also, the detection system of the present invention is easy to troubleshoot, allowing the operator to test and adjust a magnetic sensor by using a basic test-light, without the need to rotate the drums as fully nor to run the harvester engine at as high a risk. That is, the present invention allows fault detection within, for example, the first faulty ⅛ of a revolution and at near zero speed, as compared to the prior art systems where fault detection requires more movement and speed.
[0015] These aspects and others in their most preferred embodiment will become apparent from the following Detailed Description which will relate more detail regarding components of a detection system which comprise the following components:
(a) a drive gear, powered by the engine drive shaft and mounted to the external drive portion of the slip clutch; (b) a magnetic actuator element also tied to said external drive portion of the slip clutch; (c) an internal hub portion of said slip clutch, being keyed to the rotor shaft, and having a cover shield designed to intermittently shield magnetic flux emanating from the magnetic actuator; and (d) at least one magnetic reed sensor switch mounted to receive magnetic flux from the actuator unless shielded by the cover shield.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a front perspective view of the clutch slippage detection system of this invention.
[0021] FIG. 2 is a top perspective view of the clutch slippage detection system of this invention, showing the shielded mode.
[0022] FIG. 3 is also a top perspective view of the clutch slippage detection system of this invention, but showing the unshielded mode as the drum is in the fault condition.
[0023] FIG. 4 is another top perspective view of an embodiment of the drum clutch slippage system of this invention which illustrates an auxiliary sensor.
[0024] FIG. 5 a - 5 c are illustrations of reed switch modes a) actuated (unshielded), b) unactuated by virtue of being out of range, and c) unactuated by being shielded.
[0025] FIG. 6 is an illustration of the worst case scenario with an auxiliary sensor.
[0026] FIG. 7 is a graph of the sensor signals of the present invention.
[0027] FIG. 8 a is a top view of the drum clutch of the present invention without either the reed switch or the magnetic actuator.
[0028] FIG. 8 b is a perspective view of the drum clutch.
[0029] FIG. 8 c is a perspective view of the drum clutch having its hub portion separated from the external drive portion.
[0030] FIG. 9 is a from cross-sectional view of the clutch and top portion of the rotor assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] Referring now to FIGS. 1 through 9 , a rotor shaft 1 protrudes vertically through a cylindrically shaped clutch 10 . The rotor shaft 1 is affixed by key slot 11 (see FIGS. 2 and 9 ) to the internal hub 102 of clutch 10 (see FIG. 8 c ), and the hub can ratchet within the external housing 8 , which is the driven portion of clutch 10 . A cover shield 2 , shown with broken view in FIGS. 1 and 2 , is fitted over the top end of rotor shaft 1 and is keyed to rotate in engagement with rotor shaft 1 (see FIG. 9 ) at the same absolute RPMs (N 2 ) and within the same axis of rotation A ( FIG. 1 ). Cover shield 2 , along its periphery, is defined by downwardly extending fins 21 at regular intervals.
[0032] The external housing 8 , forms the outside of clutch 10 , and has mounted to its bottom, the rotor drive gear 7 , and has affixed at its edge an actuator support 6 , which carries actuator 5 . These components all rotate together, biased against clutch internal ratcheting mechanism 100 (see FIGS. 8 and 9 ). All share the same absolute input drive RPMs (N 1 ) rotating in the axis of rotation A, from the power delivered via the drive gear 7 .
[0033] When the rotor assembly 200 (see FIG. 9 ) and thus, the rotor shaft 1 , are rotating freely and without fault, the N 1 and N 2 are equal. However, when the rotor shaft 1 encounters an abnormal load or slows down due to rock, debris or branches caught in the rotor spindles, the N 1 and N 2 no longer are equal because the clutch hub 102 starts to slip within the housing 8 as springs 103 , which load pins 104 , release, leading to ratcheting sounds. That is, as the rotation of rotor shaft 1 hangs up, the clutch hub 102 begins to ratchet against the torque, of the clutch external housing 8 , provided by drive gear 7 .
[0034] The internal ratcheting hub 102 of the clutch allows a limited number of stops “n”, via pins 104 , which stops are preferably keyed to coincide with each of the fins 21 of the shield 2 , so that each stop “n” position allows one of the fins 21 , going at rate N 2 , to shield the actuator 5 when it rotates at N 1 equals N 2 . The cover shield 2 and hub 102 are keyed to the rotor shaft 1 .
[0035] A bracket 4 is fixed on the drum chassis 201 so as not to rotate. The bracket 4 supports a reed switch sensor 3 mounted to said bracket 4 so as to face the actuator 5 , for at least a certain minimum interval, during every revolution of the drive gear sprocket 7 and clutch housing 8 . Thus when N 1 and N 2 are equal, the ratchet system of the clutch hub 102 is most preferably at a stable position and therefore actuator 5 is shielded from sensor 3 , by one of the fins 21 , and, as such cannot be activated until N 1 does not equal N 2 .
[0036] Referring more particularly to FIG. 3 , a fault condition is shown, i.e. when N 1 does not equal N 2 . The rotor shaft 1 is encountering an excessive load, and the hub 102 of clutch 10 is slipping and ratcheting and the magnetic flux's pathway from actuator 5 to sensor 3 is unshielded by virtue of the fins 21 moving out of the pathway, allowing the magnetic field emitted at actuator 5 to contact the reed switch sensor 3 . The sensor 3 is thus enabled to send a fault signal. The signal is strong and can drive a load ranging from 250 milliamps to 1 amp, depending on the size of the reed switch sensor 3 . For example, the signal can drive an indicator light 300 (see FIGS. 5 a , 5 b , 5 c and 6 ) that will blink, indicating to the operator that there is a problem at the rotor in question.
[0037] FIG. 5 ( a ) graphically illustrates the reed switch sensor's ( 3 ) actuated mode for the unshielded position where the circuit is closed and a light 300 indicates warning that the clutch is slipping. At FIG. 5 ( b ) the state of the switch changes, opening the circuit and the light 300 shuts off by virtue of the actuator's ( 5 ) magnetic field being out of range of the sensor ( 3 ). FIG. 5 ( c ) shows an open circuit also, but it is open by virtue of the actuator 5 being shielded from its sensor ( 3 ) by shield ( 2 ).
[0038] Referring now to FIGS. 4 and 6 , an especially preferred embodiment of the present invention comprises a second sensor 9 mounted onto bracket 4 . Sensor 9 is a fail-safe element for the worst case scenario when N 2 =0, which means that there is complete blockage of rotor shaft 1 . That is rotor shaft 1 has completely stopped. One of the fins ( 21 ) on cover 2 is stuck at a position shielding sensor 3 , while the sprocket 7 is still spinning at N 1 RPMs which is not zero. The actuator 5 continuously passes near sensor 3 but is shielded from actuating it. The fault situation would be undetected but for sensor 9 which is clear to receive the magnetic signal when actuator 5 passes near by during revolution. FIG. 6 illustrates the open circuit at sensor 3 but successfully closing sensor 9 .
[0039] Referring now to FIG. 7 , a simple delay function is used to produce a signal that can be buffered to drive a variety of kinds of loads. The cost of producing this system, including the process controller mechanism is substantially less than prior art systems. | An improved clutch slippage detection system, comprising a magnetic actuator and at least one reed switch sensor located at a slip clutch, which reed switch changes its state, at the instant the clutch begins to overrun. | 5 |
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2011-66475, filed on Mar. 24, 2011, the entire contents of which are incorporated herein by reference.
FIELD
The embodiments discussed herein are related to methods of manufacturing semiconductor devices.
BACKGROUND
Examples of a method for mounting a semiconductor element on a circuit board or the like by flip-chip bonding include a method for soldering a semiconductor element, a method in which conductive particles are sandwiched between electrode terminals so as to be in contact with each other and are fixed with resin so as to be coupled, and a similar method.
Japanese Laid-open Patent Publications Nos. 04-309474 and 05-131279 disclose the related art.
SUMMARY
According to an aspect of the embodiments, a method of manufacturing a semiconductor device includes: forming a first layer including crystals by processing a surface of a first electrode of a semiconductor element; forming a second layer including crystals by processing a surface of a second electrode of a mounting member on which the semiconductor element is mounted; reducing a first oxide film present over or in the first layer and a second oxide film present over or in the second layer at a first temperature, the first temperature being lower than a second temperature at which a first metal included in the first electrode diffuses in a solid state and being lower than a third temperature at which a second metal included in the second electrode diffuses in a solid state; and bonding the first layer and the second layer to each other by solid-phase diffusion.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 illustrates an exemplary method for manufacturing a semiconductor device;
FIGS. 2A and 2B illustrate an exemplary method for manufacturing a semiconductor device;
FIGS. 3A to 3D illustrate an exemplary electron diffraction pattern;
FIGS. 4A and 4B illustrate an exemplary method for manufacturing a semiconductor device;
FIGS. 5A and 5B each illustrate an exemplary surface of an electrode;
FIGS. 6A , 6 B, and 6 C illustrate an exemplary method for manufacturing a semiconductor device;
FIG. 7 illustrates an exemplary semiconductor element;
FIGS. 8A and 8B each illustrate an exemplary sample;
FIGS. 9A and 9B each illustrate an exemplary fracture;
FIG. 10A illustrates an exemplary relationship between bonding temperature and die shear strength;
FIG. 10B illustrates an exemplary relationship between bonding temperature and percentage of bulk fractures;
FIGS. 11A to 11D each illustrate an exemplary chip sample;
FIGS. 12A and 12B illustrate an exemplary electrode; and
FIGS. 13A and 13B illustrate an exemplary electrode.
DESCRIPTION OF EMBODIMENTS
For example, when the pitch between electrodes is fine, the soldering of semiconductor elements may be difficult. When a semiconductor element is thin, a junction is fixed to reduce the warpage until cooling is finished, whereby treatment time may be increased.
Anisotropic conductive films prepared by dispersing conductive particles in filmy insulating resins are used to couple specific semiconductor elements such as drivers for liquid crystal displays (LCDs). The reliability of connection may be low at a temperature not lower than the glass transition temperature (Tg) of each insulating resin.
Thermocompression bonding may damage circuits in semiconductor elements because high temperature and high pressure for solid-phase diffusion are applied to electrodes.
After surfaces of electrodes are planarized by chemical mechanical polishing (CMP), the electrode surfaces are activated by argon plasma or the like in a vacuum and solid-phase diffusion bonding is performed at low temperature (surface activation bonding). When performing surface activation bonding at a temperature at which circuits in semiconductor elements are not damaged, sufficient bonding strength may not be obtained. The use of expensive vacuum equipment may cause an increase in cost.
FIG. 1 illustrates an exemplary method for manufacturing a semiconductor device.
In an operation S 1 , surfaces of electrodes of a semiconductor element and surfaces of electrodes of a mounting member for mounting the semiconductor element are machined, whereby a microcrystalline layer with a reduced grain size due to machining is provided on a surface of each electrode. The electrodes may include at least one of, for example, Cu, Sn, Al, and Ni. Cu, Sn, Al, and Ni may be likely to be oxidized. A material for forming the electrodes of the semiconductor element may be different from a material for forming the electrodes of the mounting member. The mounting member includes, for example, a lead frame, a circuit board, or the like.
FIGS. 2A and 2B illustrate an exemplary method for manufacturing a semiconductor device. As illustrated in FIG. 2A , for example, a semiconductor element 10 includes a circuit section 11 and electrodes 12 and a resin 13 is embedded between the electrodes 12 . As illustrated in FIG. 2B , surfaces of the electrodes 12 and the resin 13 are cut off with a diamond turning tool 15 including a base section 15 a and a cutting section 15 b . A microcrystalline layer including a large number of dislocations is formed on a surface of each electrode 12 . The mounting member may be treated in substantially the same or similar way. The microcrystalline layer may have a thickness of about 100 nm.
FIGS. 3A to 3D illustrate an exemplary electron diffraction pattern. The electron diffraction pattern illustrated in FIGS. 3A to 3D may be an electron diffraction pattern of the cut-off electrodes illustrated in FIG. 2A . FIG. 3A illustrates a figure corresponding to a transmission electron microscope (TEM) photograph of the cut-off electrodes. FIG. 3B illustrates an electron diffraction pattern of a site P 1 illustrated in FIG. 3A . FIG. 3C illustrates an electron diffraction pattern of a site P 2 illustrated in FIG. 3A . FIG. 3D illustrates an electron diffraction pattern of a site P 3 illustrated in FIG. 3A . With reference to FIG. 3A , a large number of dislocations are present in a region close to the surface. As illustrated in FIGS. 3B , 3 C, and 3 D, the crystal orientation of a region closer to the surface is more disordered. Although being not illustrated, the dislocation density of each electrode is substantially uniform before cutting. The electron diffraction patterns of the sites P 1 and P 2 may be substantially the same as the electron diffraction pattern of the site P 3 . A microcrystalline layer with a reduced grain size due to cutting may be present on a surface of each cut-off electrode.
Machining may be grinding, sand blasting, or the like in addition to cutting.
In an operation S 2 illustrated in FIG. 1 , after the machining of the electrode surfaces, the electrode surfaces are reduced at a temperature lower than a temperature at which solid-phase diffusion occurs in the electrodes. FIGS. 4A and 4B illustrate an exemplary semiconductor device-manufacturing method. As illustrated in FIG. 4A , for example, a circuit board 31 including electrodes 32 and the semiconductor element 10 including the electrodes 12 , are placed on a stage 22 placed in a housing 21 . A formic acid gas is introduced into the housing 21 and the housing 21 is heated to 120° C. The surfaces of the electrodes 12 and the electrodes 32 , which have the microcrystalline layers formed by machining, are reduced.
When the formic acid gas is used to perform reducing treatment, the treatment temperature may be 100° C. to 150° C. When the treatment temperature is lower than 100° C., a reducing reaction may not proceed. When the treatment temperature exceeds 150° C., the number of crystals larger than fine crystals present on a surface of each electrode may be increased because the fine crystals are recrystallized. FIGS. 5A and 5B each illustrate an exemplary surface of an electrode. The electrode surface illustrated in FIG. 5A may be a surface of a reduced electrode. In FIG. 5A , reducing treatment is performed at 120° C. In FIG. 5B , reducing treatment is performed at 180° C. Grain boundaries between relatively large crystals formed by recrystallization may be present in the electrode surface illustrated in FIG. 5B .
Formic acid, hydrogen radicals, or a carbon monoxide gas may be used as a reductant. When such hydrogen radicals are used, the treatment temperature may be 25° C. to 150° C. When the treatment temperature exceeds 150° C., the number of crystals larger than fine crystals present on the surface of each electrode may be increased because the fine crystals are recrystallized. When such a carbon monoxide gas is used, the treatment temperature may be 50° C. to 150° C. When the treatment temperature is lower than 50° C., a reducing reaction may not proceed. When the treatment temperature exceeds 150° C., the number of crystals larger than fine crystals present on the surface of each electrode may be increased because the fine crystals are recrystallized.
In an operation S 3 illustrated in FIG. 1 , after reducing treatment, the electrodes 12 of the semiconductor element 10 are aligned with the electrodes of the mounting member at a temperature lower than a temperature at which solid-phase diffusion occurs in the electrodes. FIGS. 6A , 6 B, and 6 C illustrate an exemplary semiconductor device-manufacturing method. As illustrated in FIG. 6A , for example, the electrodes 12 of the semiconductor element 10 are horizontally aligned with the electrodes 32 of the circuit board 31 in such a manner that the electrodes to be bonded to each other are arranged opposite to each other. A microcrystalline layer 12 b is located closer to the surface of each electrode 12 than a base section 12 a of the electrode 12 . A microcrystalline layer 32 b is located closer to the surface of each electrode 32 than a base section 32 a of the electrode 32 . The microcrystalline layer 12 b and the microcrystalline layer 32 b are arranged opposite to each other.
In an operation S 4 illustrated in FIG. 1 , the electrodes are bonded to each other by solid-phase diffusion in such a manner that voltages are applied between the electrodes and the electrodes are heated to a temperature at which solid-phase diffusion occurs. Solid-phase diffusion bonding may be performed in a non-oxidizing atmosphere, for example, in a vacuum or in an inert gas atmosphere. For example, the electrode 12 and electrodes 32 illustrated in FIG. 4B are brought into contact with each other, whereby the microcrystalline layer 12 b and the microcrystalline layer 32 b contact with each other as illustrated in FIG. 6B . Pressurizing and heating are performed and metal atoms in the microcrystalline layer 12 b and metal atoms in the microcrystalline layer 32 b diffuse in a solid state. A temperature at which solid-phase diffusion occurs may be about 150° C. to 250° C. As illustrated in FIG. 6C , the boundary between the electrodes 12 and 32 disappear and a connection member 30 including a bonding section 30 a is formed in a region corresponding to a region in which the microcrystalline layers 12 b and 32 b are present. When the electrodes include substantially the same kind of metal, solid-phase diffusion tends to occur as a grain size reduces. Therefore, high bonding strength may be obtained at a temperature lower than or substantially equal to the temperature of surface activation bonding performed using bumps planarized by chemical mechanical polishing.
Since solid-phase diffusion bonding is performed between the reduced microcrystalline layers, high bonding strength may be obtained even at relatively low temperatures. In surface activation bonding performed using bumps planarized by chemical mechanical polishing, for example, heating is performed at about 250° C. to 300° C. and sufficient bonding strength may not be obtained. In the solid-phase diffusion bonding of the reduced microcrystalline layers, sufficient bonding strength may be obtained by heating at about 150° C. to 250° C.
Since no solder is used, no barrier metal such as Ti or Ni is used; hence, costs and man-hours may be reduced. Since similar metals are bonded to each other, the formation of voids due to alloying is reduced, whereby high reliability may be achieved.
The semiconductor element may be, for example, a large-scale integration (LSI) chip, a memory, or a transistor such as a GaN high electron mobility transistor (HEMT). FIG. 7 illustrates an exemplary semiconductor element. The semiconductor element illustrated in FIG. 7 may be a GaN HEMT 42 mounted on a circuit board 41 . The circuit board 41 and the GaN HEMT 42 are coupled to each other with a source connection member 43 s , a drain connection member 43 d , and a gate connection member 43 g . The source connection member 43 s , the drain connection member 43 d , and the gate connection member 43 g are coupled to a source, drain, and gate, respectively, of the GaN HEMT 42 . The circuit board 41 may include, for example, a copper-clad laminate.
FIGS. 8A and 8B each illustrate an exemplary sample. For example, a chip sample 51 a illustrated in FIG. 8A may be prepared by cutting, reduction, alignment, and solid-phase diffusion bonding as described above. For example, a chip sample 51 b illustrated in FIG. 8B may be prepared by CMP instead of cutting and by reduction, alignment, and solid-phase diffusion bonding.
As illustrated in FIG. 8A , the chip sample 51 a and a circuit board sample 61 a are bonded together. In the preparation of the chip sample 51 a , conductive layers 53 and an insulating layer 54 are formed on a surface of a S 1 substrate 52 and bumps 55 a are formed on the conductive layers 53 . The surface of each bump 55 a is cut off, whereby a microcrystalline layer is formed. In the preparation of the circuit board sample 61 a , conductive layers 63 and an insulating layer 64 are formed on a surface of a S 1 substrate 62 and a plate bump 65 a is formed on the conductive layers 63 . The surface of the plate bump 65 a is cut off, whereby a microcrystalline layer is formed. A Cu electrode may be used as a bump material. Since the hardness of the Cu electrode is higher than the hardness of an Au electrode, a thick microcrystalline layer may be formed. As for cutting, a fly cutting process using a single-crystalline diamond turning tool may be used. In the fly cutting process, all workpieces, for example, bumps, formed on a wafer are machined at substantially the same speed, whereby a microcrystalline layer on the surface of each bump may have substantially a uniform thickness. An R-shaped diamond turning tool with a nose diameter of 10 mm may be used. The edge of the turning tool may have a nose radius of 50 nm to 300 nm.
As illustrated in FIG. 8B , the chip sample 51 b and a circuit board sample 61 b are bonded together. In the preparation of the chip sample 51 b , conductive layers 53 and an insulating layer 54 are formed on a surface of a S 1 substrate 52 and bumps 55 b are formed on the conductive layers 53 . Surfaces of the bumps 55 b are subjected to CMP. In the preparation of the circuit board sample 61 b , conductive layers 63 and an insulating layer 64 are formed on a surface of a S 1 substrate 62 and a plate bump 65 b is formed on the conductive layers 63 . A surface of the plate bump 65 b is subjected to CMP. In CMP, a hydrogen peroxide slurry and an abrasive pad made of polyurethane may be used.
The chip samples 51 a and 51 b may have a size of 5 mm×5 mm×0.6 mm. In the chip sample 51 a , 392 of the bumps 55 a are arranged on a peripheral section of the chip sample 51 a . In the chip sample 51 b , 392 of the bumps 55 b are arranged on a peripheral section of the chip sample 51 b . The pitch between the bumps 55 a and the pitch between the bumps 55 b may be 40 μm. The bumps 55 a and 55 b may have a size of 25 mm×25 mm×0.008 mm. The circuit board samples 61 a and 61 b may have a size of 5 mm×5 mm×0.6 mm. The plate bumps 65 a and 65 b may have a size of 10 mm×10 mm×0.6 mm and may be arranged one by one. In order to avoid errors due to misalignment, a large plate bump may be used. The accuracy of alignment may not be taken into account depending on a plate bump used.
The chip samples 51 a and 51 b are reduced at a temperature of 120° C. for 30 minutes using a formic acid gas. Since the plate bumps 65 a and 65 b are used, alignment may be simply performed. In solid-phase diffusion bonding (thermocompression bonding), two different bonding temperatures may be used, the bonding time may be set to 30 minutes, and the bonding pressure may be set to 300 MPa.
The chip samples 51 a and 51 b are subjected to a die shear test and bonding interfaces are observed. In the die shear test, for example, the shear strength is measured and the fracture mode percentage is investigated. FIGS. 9A and 9B each illustrate an exemplary fracture. FIG. 9A illustrates a bulk fracture in which a breakage 70 is caused in one of the bumps 55 a or 55 b . FIG. 9B illustrates an interface fracture in which a breakage 70 is caused at the interface between one of the bumps 55 a or 55 b and the plate bump 65 a or the 65 b , respectively. In the investigation of the fracture mode percentage, the percentage of the number of bulk fractures in the sum of the number of the bulk fractures and the number of interface fractures. In the observation of a bonding interface, a region near the bonding interface is processed with a focused ion beam (FIB) and a cross section including the bonding interface is observed with a scanning electron microscope (SEM).
FIG. 10A illustrates an exemplary relationship between bonding temperature and die shear strength. FIG. 10B illustrates an exemplary relationship between bonding temperature and percentage of bulk fractures. As illustrated in FIG. 10A , the chip sample 51 a has a shear strength that is about two times that of the chip sample 51 b at a bonding temperature of 200° C. and 250° C. As illustrated in FIG. 10B , in the chip sample 51 a , the percentage of bulk fractures is close to 100% at a bonding temperature of 200° C. and 250° C. In the chip sample 51 b , the percentage of bulk fractures is low at a bonding temperature of 200° C. In the chip sample 51 a , high bonding structure may be obtained by solid-phase diffusion bonding at about 200° C.
FIGS. 11A to 11D each illustrate an exemplary chip sample. FIGS. 11A to 11D may be illustrations corresponding to SEM photographs. FIG. 11A illustrates a chip sample 51 a prepared at a bonding temperature of 200° C. FIG. 11B illustrates a chip sample 51 a prepared at a bonding temperature of 250° C. FIG. 11C illustrates a chip sample 51 b prepared at a bonding temperature of 200° C. FIG. 11D illustrates a chip sample 51 b prepared at a bonding temperature of 250° C. Circles illustrated in FIGS. 11A to 11D indicate the presence of voids. As illustrated in FIG. 11A , most bonding interfaces are lost, slight bonding interfaces are observed, and slight voids may be present at a bonding temperature of 200° C. As illustrated in FIG. 11B , a small number of voids are present and bonding interfaces are, however, lost at a bonding temperature of 250° C. Since voids adjacent to bonding surfaces migrate due to solid-phase diffusion and recrystallization, voids may be scattered. Bonding interfaces may be lost due to the recrystallization of fine crystals. As illustrated in FIGS. 11C and 11D , in the chip sample 51 b , bonding interfaces are observed in wide regions independently of bonding temperature. The number of microcrystalline layers is reduced by the action of a treatment solution after CMP and therefore no recrystallization may occur.
FIGS. 12A and 12B each illustrate an exemplary electrode. FIGS. 12A and 12B may correspond to TEM photographs of electrodes of a chip sample 51 a . FIGS. 13A and 13B each illustrate an exemplary electrode. FIGS. 13A and 13B may correspond to TEM photographs of electrodes of a chip sample 51 b . A region illustrated in FIG. 12B and a region illustrated in FIG. 13B may correspond to a quadrangle illustrated in FIG. 12A and a quadrangle illustrated in FIG. 13A , respectively. As illustrated in FIGS. 12A and 12B , in the chip sample 51 a , a region including fine crystal grains is present in a surface section. As illustrated in FIGS. 13A and 13B , large crystal grains are present over the whole chip sample 51 b . The possibility of recrystallization depends on the difference between structures and therefore differences between bonding strengths may be caused.
All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. | A method of manufacturing a semiconductor device includes: forming a first layer including crystals by processing a surface of a first electrode of a semiconductor element; forming a second layer including crystals by processing a surface of a second electrode of a mounting member on which the semiconductor element is mounted; reducing a first oxide film present over or in the first layer and a second oxide film present over or in the second layer at a first temperature, the first temperature being lower than a second temperature at which a first metal included in the first electrode diffuses in a solid state and being lower than a third temperature at which a second metal included in the second electrode diffuses in a solid state; and bonding the first layer and the second layer to each other by solid-phase diffusion. | 7 |
FIELD OF THE INVENTION
The present invention relates to golf balls, and, more particularly, to golf ball dimples.
BACKGROUND OF THE INVENTION
It has long been known that the flight of a golf ball is dramatically improved if depressions or “dimples” are impressed on the surface of the golfball sphere. Aerodynamic studies and fluid mechanics principles attribute this improvement to the fact that the surface roughness produced by the dimples create turbulence at the surface of the sphere and hence what is known as a turbulent boundary layer. This turbulent boundary layer decreases the aerodynamic drag of the ball, thus allowing it to travel much farther than a smooth ball.
With conventionally dimpled golf balls, the creation of a turbulent boundary layer is highly velocity dependent. This is illustrated in FIGS. 1-4, labeled as prior art, which consider the flow of air or fluid over the surface of a portion of a golf ball 20 . FIG. 1 shows the cross section of a typical, spherically concave golf ball dimple 22 which would be on the surface of the golf ball 20 . In FIG. 2, air 24 passes slowly over the dimple 22 of FIG. 1 in the direction as indicated by the arrows. The air 24 conforms to the shape of the dimple 22 at its surface and has insufficient velocity or direction change to create turbulence or vortices.
FIG. 3 is a view of the same dimple 22 with the air 24 passing over the surface at a high enough velocity such that the air 24 cannot conform to the shape of the dimple 22 . Instead, the air 24 slams into the back wall of the dimple 22 and quickly changes direction. As it exits the dimple 22 , the air 24 cannot quickly re-conform to the spherical surface 26 of the golf ball 20 . This results in the generation of turbulence and vortices, and thus the creation of the turbulent boundary layer.
FIG. 4 is a view of the same dimple 22 with the air 24 passing over the dimple at an intermediate velocity. The air 24 cannot perfectly conform to the surface of the dimple 22 , but is in much greater contact than the air in FIG. 3 where the velocity is higher. As the air 24 exits the dimple 22 , its velocity is such that it soon re-conforms to the surface 26 of the golf ball 20 . Since this is the case, a turbulent boundary layer cannot be maintained even though some turbulence is generated at the intersection of the trailing edge of the dimple and the surface of the sphere.
The number, size, shape, and depth of the dimples all have an influence on the amount of distance improvement a dimpled golf ball will exhibit. Specifically, as the depth, diameter, and number of the dimples is gradually increased, the frictional drag of the ball is increased by the surface roughness of the dimples, and the aerodynamic drag is decreased. Up to a certain point, the effect of the reduction in aerodynamic drag far exceeds the effect of the increase of the frictional drag, and the golf ball exhibits significant distance improvement. Once this point is reached, though, further increases in dimple volume results in decreasing distance performance. This is because there is an increase in the frictional drag and an increase in aerodynamic drag due to the thickness of the generated boundary layer.
Those skilled in the art of designing golf balls have long known that the ideal dimple for a golf ball would change its shape during the flight of the ball. The ball would have low surface roughness when the velocity was high and turbulence was easy to generate. The roughness would increase gradually as the velocity decreased so as to maintain a uniform boundary layer, and would again decrease gradually to lower surface roughness during the descent of the ball, when one of the drag components would tend to keep the ball in flight. Unfortunately, there is no existing technology which allows golf balls to have such a feature.
Many attempts have been made to simulate at least a portion of the aforementioned ideal dimple characteristics. While there have been some improvements, these have been very modest in nature.
For example, triangle- or hexagon-shaped dimples having sharp edges have been used on golf balls. While these sharp edges assist in generating vortices and turbulence, they are located at the surface of the sphere and arc hence in the airflow during the entire flight of the ball. Their effect must therefore be regulated so as not to produce too much turbulence early on in the flight, making them ineffectual during later portions of the flight.
Other dimple shapes have also been proposed. U.S. Pat. No. 5,470,076 to Cadorniga discloses providing dimples inside dimples, wherein each dimple includes an outer concentric portion having a shallow spherical concavity and an inner concentric portion having a deeper spherical concavity, but these offer no projections in the airstream for generating vortices. Also, U.S. Pat. No. 5,536,013 to Pocklington discloses a toroidal dimple with a center projection extending up to the surface of the sphere. Since this projection reaches the surface of the sphere, it suffers from the same problems as the sharp edged dimples described above.
Turning now to the prior art shown in FIG. 5, U.S. Pat. No. 4,877,252 to Shaw discloses pairs of normal sized dimples 28 , 30 that overlap by as much as twenty percent. A single projection 32 below the level of the golf ball surface 26 is formed where the two dimples 28 , 30 overlap. Theoretically, during flight at intermediate velocities, air strikes the projection 32 , further helping to create a turbulent boundary layer. However, because the dimples 28 , 30 overlap by no more than twenty percent, they form a large area on the surface of the golf ball whose width is at least 1.8 times the diameter of a single dimple. This can be seen by comparing the indicated diameter D of the dimple 22 in FIG. 1 to the indicated diameter (1.8D) of the overlapping dimples 28 , 30 in FIG. 5 . Aerodynamically, the overlapping dimples 28 , 30 in FIG. 5 will behave approximately as two independent dimples with only a slight improvement in flight characteristics. This is because the projection 32 is so far from the edges of the dimples 28 , 30 that the air passing over the golf ball during flight will still have a chance to conform to the shape of the dimples even at relatively high velocities, e.g., as shown in FIG. 4 .
U.S. Pat. No. 4,960,282, also to Shaw, discloses pairs or chains of dimples that preferably overlap one another by at least 0.02 inches (0.508 mm) or twenty percent. Although this disclosed structure potentially reduces the velocity at which a turbulent boundary layer is formed, it still does not provide enhanced flight characteristics at lower velocities. This is because the projection is still quite far from the edges of the dimples, and because the turbulent boundary layer producing effect of the overlapping pairs of dimples is highly directionally dependent. That is, with reference to FIG. 5, when air 24 flows in either of the directions indicated by the arrows, a turbulent boundary layer will potentially be formed, depending on the velocity of the golf ball 20 and the particular dimensions of the overlapping dimples. However, if the air flows along (instead of across) the projection 32 (e.g., normal to FIG. 5 ), no boundary layer effects will be produced.
Accordingly, it is a primary object of the present invention to produce a golf ball with unique dimples that overcomes the deficiencies of the prior art to increase the flight of the ball.
Another object is to provide golf ball dimples having a common cross-sectional structure wherein a turbulent boundary layer is formed at low, medium, and high velocities.
Yet another object is to provide golf ball dimples wherein the creation of a turbulent boundary layer is not dependent upon the direction air flows over the dimples.
Still another object is to provide golf ball dimples wherein a turbulent boundary layer can be produced without a resultant increase in frictional drag.
SUMMARY OF THE INVENTION
In order to solve the aforementioned problems and meet the stated objects, the present invention discloses a plurality of vortex generating golf ball dimples for producing a turbulent boundary layer on the surface of the golf ball during a longer portion of the golf ball's flight, without unnecessarily increasing the size of the boundary layer in the early portions of the flight. This results in the golf ball traveling a longer distance.
Each dimple is a composite of a plurality of overlapping smaller concave sections, with the dimple preferably being dimensioned to lie within a circumscribed circle having about the same diameter as a conventional dimple. The preferred embodiments of the dimple comprise a plurality of peripheral spherical sections overlapping a central spherical section to form a ridge-like polygon. The polygon, the top edge of which lies below the outer edges of the dimple, acts as a vortex generating structure within the dimple con-cavity for producing the turbulent boundary layer. In fact, each pair of opposite or near opposite sides of the polygon has a common cross-sectional shape or structure. The aerodynamic characteristics of the cross-sectional structure are such that the turbulent boundary layer is formed about the dimple at even relatively low velocities. Also, because the cross-sectional structure is seen across the dimple from a plurality of orientations, the boundary layer producing effects of the dimple are directionally independent.
To generate air vortices, and thus the turbulent boundary layer, the opposite or near opposite sides of the polygon act as spaced apart vortex generating projections extending up from the bottom of the dimple. At high velocities, because the projections lie below the outer edge of the dimple, air, which can only slightly conform to the shape of the dimple, passes over the projections and only hits the trailing edge of the dimple, as in a conventional spherical dimple. This provides sufficient air vortices to create a turbulent boundary layer, without the projections unnecessarily and detrimentally contributing. At intermediate velocities, the air conforms a bit more to the shape of the dimple, and vortices are created as the air encounters at least one of the projections. Although these vortices are not necessarily strong enough to create a boundary layer by themselves, when combined with the now less forceful vortices at the trailing edge of the dimple, they are sufficient. Finally, at low velocities, the air generally conforms to the shape of the dimple, and encounters both the projections. The resultant vortices are sufficient, when combined with the vortices at the trailing edge of the dimple, to create the turbulent boundary layer.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the present invention will become better understood with respect to the following description, appended claims, and accompanying drawings, in which:
FIG. 1 is a cross-sectional view of a golf ball dimple according to the prior art;
FIG. 2 is a conceptual view of air flow over the dimple of FIG. 1 at a low velocity;
FIG. 3 is a conceptual view of air flow over the dimple of FIG. 1 at a high velocity;
FIG. 4 is a conceptual view of air flow over the dimple of FIG. 1 at an intermediate velocity;
FIG. 5 is a cross-sectional view of overlapping golf ball dimples according to the prior art;
FIG. 6 is a view of a cross-sectional structure common to a plurality of complex dimples of the present invention and as shown in FIGS. 10-13;
FIG. 7 is a conceptual view of air flow over the cross-sectional structure of FIG. 6 at a high velocity;
FIG. 8 is a conceptual view of air flow over the cross-sectional structure of FIG. 6 at an intermediate velocity;
FIG. 9 is a conceptual view of air flow over the cross-sectional structure of FIG. 6 at a low velocity;
FIG. 10 is a top plan view of a first complex dimple having the cross-sectional structure shown in FIG. 6;
FIG. 11 is a top plan view of a second complex dimple having the cross-sectional structure shown in FIG. 6;
FIG. 12 is a top plan view of a third complex dimple having the cross-sectional structure shown in FIG. 6;
FIG. 13 is a top plan view of a fourth complex dimple having the cross-sectional structure shown in FIG. 6; and
FIG. 14 is a perspective view of a golf ball incorporating the complex dimples shown in FIGS. 11 and 13 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to FIGS. 6-14, a preferred embodiment of a complex dimple cross-sectional structure 42 and complex dimples 40 a - 40 d having the cross-sectional structure, according to the present invention, will now be given. When a golf ball 20 (e.g., as seen in FIG. 14) is provided with the dimples 40 a - 40 d , it exhibits superior driving length. This is because the dimples have unique aerodynamic features 42 , 48 , 56 a - 56 l , etc., as described below, that substantially improve and enhance the flight characteristics of the golf ball when it travels at low, medium, and high velocities after being struck by a golfer.
Various complex dimples 40 a - 40 d of the present invention are shown in FIGS. 10-13, respectively. By “complex,” it is meant that each dimple, as a result of being a composite of a plurality of smaller, spherically (or otherwise) shaped sections, has a vortex generating structure within the dimple concavity for producing a turbulent boundary layer. Each of the complex dimples 40 a - 40 d has the cross-sectional structure 42 as shown in FIGS. 6-9. The aerodynamic characteristics of the cross-sectional structure 42 , as explained below, are such that a turbulent boundary layer is formed about the complex dimples 40 a - 40 d at even relatively low velocities. Thus, the golf ball 20 provided with a plurality of the complex dimples 40 a - 40 d (see FIG. 14) will exhibit superior distance and flight characteristics.
With reference to FIG. 6, the complex dimples 40 a - 40 d are similar in cross-section (from the perspective shown) to the spherical dimple 22 in FIG. 1, to the extent that they both have the same diameter D and define an at least partially spherical concavity. However, the cross-sectional structure 42 of the complex dimples 40 a - 40 d includes first and second edged projections or “vortex generators” 44 a , 44 b extending upwards from the dimple bottom. The tips or edges 46 a , 46 b of the vortex generators 44 a , 44 b , respectively, lie below a plane which would be coincident with the intersection of the outer edges of the dimple with the spherical surface 26 of the golf ball 20 .
FIG. 7 shows the effect of the vortex generators 44 a , 44 b on the flow of air 24 across one of the complex dimples 40 a - 40 d at high velocities. The air 24 passes over the vortex generators 44 a , 44 b and collides with the rear wall of the dimple without being affected by the vortex generators. Hence, the dimple will perform essentially the same as the conventional spherical dimple 22 in FIG. 3 .
FIG. 8 shows the cross-sectional structure 42 of FIG. 6 with air 24 passing over the dimple at an intermediate velocity. The air 24 hits the first vortex generator 44 a and must quickly change direction. This abrupt change generates turbulence which is then additive to the turbulence created by the trailing edge of the dimple. Hence, a turbulent boundary layer is maintained at this velocity.
FIG. 9 shows the effect of air 24 passing over the vortex generators 44 a , 44 b at a low velocity. The air now strikes both of the vortex generators 44 a , 44 b at the bottom of the dimple. Even though the air 24 is traveling at low velocity, some turbulence is generated by the passage of the air 24 over the vortex generators 44 a , 44 b due to the air's necessary abrupt direction change.
As mentioned above, the top edges 46 a , 46 b of the vortex generators lie below the outer edge of the complex dimples 40 a - 40 d . This is because a golf ball's velocity is constantly changing during flight, and the vortex generators are not needed in the early, high velocity portion of the flight. Note that if the vortex generators extended upwards as far as the outer edge of the dimple, frictional drag would be greatly increased without much additional benefit resulting from the stronger turbulent boundary layer.
A first of the complex dimples 40 a is shown in FIG. 10, and is the simplest construction available by which to provide the cross-sectional structure 42 . The first dimple 40 a is merely a spherical section 48 intersecting a toroidal section 50 . However, vortex generators function best if their upper edges are substantially linear in nature rather than being arced. Therefore, the first complex dimple 40 a , although functional in providing improved flight characteristics, is not preferred over the remaining complex dimples 40 b - 40 d described herein.
FIGS. 11-13 show second, third and fourth complex dimples 40 b - 40 d , respectively. Each of these complex dimples comprises a plurality of spherical sections or concave walls which overlap in such a manner that the peripheral or outer sections 54 a - 54 l (as applicable) form a polygon when they intersect a central section 52 a - 52 c (as applicable.) This requires that all the peripheral sections be essentially the same distance radially from the center P of the central section 52 a - 52 c , and further that the peripheral sections be essentially equally spaced (at equal angles) around the perimeter of the central section 52 a - 52 c.
FIG. 11 shows the second complex dimple 40 b created by the central spherical section 52 a being intersected by three outer spherical sections 54 a - 54 c . Specifically, the three outer spherical sections 54 a - 54 c are symmetrically arranged 120° apart from one another about the center point P of the central spherical section 52 a . This results in three linear segments 56 a - 56 c forming a triangle and three additional linear segments 58 a - 58 c which project from the apices of the formed triangle to the intersection of two adjacent outer spherical sections. Any two adjacent linear segments of the triangle ( 56 a - 56 b , 56 b - 56 c , or 56 c - 56 a ) provide the preferred linear edges of the vortex generators. For example, as can be seen from the indicated cross-section line 6 — 6 , the linear segments 56 a , 56 b form the vortex generator edges 46 a , 46 b.
It should be noted that the lengths of all the linear segments for the complex dimples 40 b - 40 d described herein are dependent upon the relationship of the radii of all the spherical sections. Although the spherical sections FIGS. 11-13 have been given equal radii for convenience and clarity of illustration, the spherical sections could also have differing radii. If this were done, the polygon would be irregular. While it is not necessary that the sides of the polygons be the same length, this is preferred since it offers the most aesthetically pleasing appearance.
FIG. 12 shows the third complex dimple 40 c created by the central spherical section 52 b being intersected by four peripheral spherical sections 54 d - 54 g . Specifically, the four outer spherical sections 54 d - 54 g are symmetrically arranged 90° apart from one another about the center point P of the central spherical section 52 b . This results in four linear segments 56 d - 56 g forming a square and four additional linear segments 58 d - 58 g which project from the apices of the formed square to the intersection of two adjacent outer spherical sections. Any two opposed linear segments of the square ( 56 d - 56 e or 56 f - 56 g ) provide the preferred linear edges of the vortex generators and the requisite cross-sectional structure 42 . For example, as can once again be seen from the indicated cross-section line 6 — 6 , two of the linear segments 56 d , 56 e form the vortex generator edges 46 a , 46 b.
FIG. 13 shows the fourth complex dimple 40 d created by the central spherical section 52 c being intersected by five outer spherical sections 54 h - 54 l . Specifically, the five outer spherical sections 54 h - 54 l are symmetrically arranged 72° apart from one another about the center point P of the central spherical section 52 c . This results in five linear segments 56 h - 56 l forming a pentagon and five additional linear segments 58 h - 58 l which project from the apices of the formed pentagon to the intersection of two adjacent outer spherical sections. Any two non-adjacent linear segments of the pentagon (e.g., 56 h - 56 i , 56 h - 56 k , 56 j - 56 l ) provide the preferred linear edges of the vortex generators. For example, as seen from the indicated cross-section line 6 — 6 , two of the linear segments 56 h , 56 i form the vortex generator edges 46 a , 46 b . Again, the length of the segments is dependent on the relationship of the radii of all of the spherical sections 52 c , 54 h - 54 l , and again, in FIG. 13 all the spherical sections have equal radii for convenience.
By incorporating further outer spherical sections around the central section 52 a - 52 c , it is possible to provide further complex dimples having both the desired cross-sectional structure 42 and central polygons having any number of sides as desired.
Each of the complex dimples 40 a - 40 d is preferably the same overall size as a conventional dimple. In other words, the complex dimples should be dimensioned to be circumscribed by a circle having the same diameter as a conventional dimple, about 0.100 to 0.185 inches (2.540 to 4.699 mm), with the radii of the circles generated by the intersection of the spherical dimple sections with the sphere of the ball preferably being between about 0.025 to 0.047 inches (0.635 to 1.194 mm) in length. If the complex dimples are dimensioned much wider, the projections 46 a , 46 b will become spaced too far apart and their vortex generating characteristics will diminish.
Any combination of the complex dimples 40 a - 40 d (or further complex dimples made according to the present invention) can placed on the surface 26 of the golf ball 20 to either enhance the performance of the golf ball or to improve the aesthetics of the ball. All the dimples on the golf ball do not need to have vortex generators. Rather, it is anticipated that a uniform disbursement of vortex-generating complex dimples over the surface of the golf ball, intermingled with traditional dimples, will give both the best performance and the best aesthetics. As an example, FIG. 14 shows a polar view of the golf ball 20 with the second and fourth of the above described vortex-generating complex dimples 40 b , 40 d interspersed among traditional dimples 22 .
Although the present invention has been illustrated as having spherically concave sections, one of ordinary skill in the art will appreciate that the sections can be non-spherical without departing from the spirit and scope of the invention.
Since certain changes may be made in the above described golf ball dimple structures with vortex generators, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention. | A vortex generating golf ball dimple for producing a turbulent boundary layer on the surface of a golf ball during its flight is a composite of a plurality of overlapping smaller concave sections. Preferably, the dimple is a plurality of peripheral spherical sections overlapping a central spherical section to form a ridge-like polygon. The polygon, the top edge of which lies below the outer edges of the dimple, acts as a vortex generating structure within the dimple concavity for producing the turbulent boundary layer. Each pair of opposite or near opposite sides of the polygon has a common cross-sectional shape or structure. The aerodynamic characteristics of the cross-sectional structure are such that the turbulent boundary layer is formed about the dimple at even relatively low velocities without any unnecessary interference being produced at high velocities. Because the cross-sectional structure is seen across the dimple from a plurality of orientations, the boundary layer producing effects of the dimple are directionally independent. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 09/095,829, filed Jun. 11, 1998 now U.S. Pat. No. 6,177,659.
FIELD OF THE INVENTION
The present invention relates to a rice cooker having a microcomputer for general household or professional use.
BACKGROUND OF THE INVENTION
Recently, rice cookers for cooking rice with high power for enhancing the rice cooking performance have been developed and distributed widely. There are also rice cookers capable of cooking rice at different levels of softness by the same amount of water.
Conventionally, this kind of rice cooker was composed as shown in FIG. 12 In FIG. 12, a body (rice cooker main body) 1 is a cylindrical structure having an open top, and inside of the body 1 is disposed a protective frame 2 which accommodates an inner pan 3 . The protective frame 2 is a cylindrical structure with a bottom made of nonmetallic material, and the upper end of the protective frame 2 is engaged with the inner circumference of the upper end of the body 1 .
The inner pan 3 has a flange 4 projecting outside at the opening of the upper end, and this inner pan 3 is disposed detachably in the protective frame 2 , by mounting the flange 4 on the top of an upper frame 5 in a suspended state. At the outside of the protective frame 2 , an induction coil 6 for heating the inner pan 3 is disposed, and this induction coil 6 is supported by a coil cover 7 formed of a heat resistant resin material in the lower part of the outer circumference of the protective frame 2 so that the distance to the outer circumference of-the inner pan 3 may be constant. In the center of the induction coil 6 , a pan sensor 8 for detecting the temperature of the inner pan 3 is disposed.
An outer lid 9 made of synthetic resin is rotatably supported on a hinge member 10 formed integrally on the top of the upper frame 5 through a pin 11 . An inner cover 12 is affixed at the inside of the outer lid 9 . A heat releasing plate 13 , being a heating element, is fixed to the inner cover 12 , and an induction coil 15 supported by a coil support stand 14 is positioned on the top of this heat releasing plate 13 . By the electromagnetic action of this induction coil 15 , the heat releasing plate 13 generates heat. To this heat releasing plate 13 , a lid sensor 16 for detecting the temperature of the heat releasing plate 13 is directly adhered with an aluminum tape, and the temperature of the heat releasing plate 13 is detected.
An engaging member 17 is positioned on the opposite side of the hinge member 10 and is formed integrally on the upper end of the protective frame 2 , and confronting to this engaging member 17 , an engaging lever 18 is rotatably supported on the outer lid 9 through a lever pin 19 . A pan packing 20 is to enclose the inner pan 3 by pressing to the flange 4 of the inner pan 3 when the outer lid 9 is closed. A steam tube 21 provided in the center of the outer lid 9 is to prevent rice gruel from boiling over to outside.
A control board 22 is to control power feed to the induction coils 6 , 12 , and also control input and output of signals from the pan sensor 8 and lid sensor 16 and signal of operation display unit 23 provided before the top of the body 1 . A cooling fan 24 is to cool the induction coil 6 and control board 22 . The control board 22 judges the amount of rice and water in the inner pan 3 in the rice cooking amount judging process while cooking rice by the temperature detection signal from the lid sensor 16 , and determines the power feed state to the induction coil 6 depending on the result of judging.
In the conventional rice cooker having such constitution, however, the size of the body 1 is large for the inner pan 3 of the rice cooker, and it is not convenient for carrying or installing, or owing to the recent increase in the number of cooking software, the number of operation keys increases and when large keys are used for the ease of handling, the size of the entire rice cooker further becomes larger.
On the other hand, when much water is used in cooking rice, it boils over, and the power supply in cooking is stopped before boiling over. However, unless power is supplied in cooking, the temperature rise of rice is not sufficient, and the taste may be sometimes slightly inferior.
Besides, when detaching or attaching the inner pan 3 , it is necessary to open or close the outer lid 9 , and particularly when closing the outer lid 9 , the front side of the body 1 on the top of the outer lid 9 must be held down, and if the operation display unit 23 is located on the top of the outer lid 9 in a range possibly held by hand, an operation key may be pressed by mistake.
Moreover, since the heat is high, to cook the rice soft, in particular, if more water is added than usual for cooking rice, it often causes boiling-over.
SUMMARY OF THE INVENTION
It is hence a first object of the invention to realize a rice cooker of compact structure which does not boil over.
It is a second object of the invention to realize a rice cooker constituted so as to prevent wrong operation if the operation unit is touched by mistake when closing the lid.
It is a third object of the invention to realize a rice cooker capable of preventing boiling-over, without lowering the rice cooking performance, by detecting rice gruel rising over the inner pan.
To achieve the objects, the rice cooker of the invention comprises a rice cooker main body (hereinafter called main body), an inner pan detachably accommodated in the main body, a lid to cover the upper opening of the main body, and rice gruel detecting means for detecting flow of rice gruel in cooking rice. Preferably, the rice gruel detecting means is composed of a float and a float detecting unit, and the rice gruel detecting means is preferably provided in the lid, or in a passage of rice gruel, that is, in the steam tube of the lid or in the upper part of the inner pan.
In this constitution, the entire rice cooker is made compact, and the convenience of installation and carrying is much improved, and since the steam tube can be easily detached from the lid and cleaned, so that an easy-to-clean and easy-to-handle rice cooker is presented. Still more, by adjusting the heating amount depending on the rising state of rice gruel, boiling-over can be prevented, and a favorable rice cooking performance is always obtained.
In the rice cooker of the invention, it is preferred to be constituted so as to supply electric power to the inner pan continuously until the rice gruel detecting means operates, to supply again when rice gruel is no longer possible to flow out of the rice cooker. In this constitution, when finishing cooking, sufficient heating can be applied to rice and water, and tasty rice is cooked, and the taste of the cooked rice is improved.
The rice cooker of the invention is preferred to comprise a bottom heating coil for induction heating of the inner pan, control means for controlling supply of high frequency power to the bottom heating coil, a steam tube disposed in the lid for exhausting the steam generated in the inner pan, and rice gruel detecting means disposed in the steam tube. By controlling the power supply amount to the bottom heating coil depending on the detecting state of the rice gruel detecting means, boiling-over of rice gruel can be effectively prevented in a compact steam tube size.
Preferably, the rice gruel detecting means is constituted so as to make use of the move of a float moving due to opening and closing of the lid and expansion and contraction of rice gruel generated in the inner pan. As a result, generation of rice gruel can be detected in a simple constitution. Preferably, the rice gruel detecting means comprise a float made of columnar or spherical ferrite disposed so as to roll over a slope provided in the bottom of the steam tube, and a float detecting unit composed of a lead switch for detecting the float. Moreover, preferably, the slope has a groove for flow of rice gruel, and also has a convex portion for the float to move along the groove. Therefore, the structure is also suited to counter-flow of rice gruel. When the float has such a weight as not to be moved by the steam and to be moved by the passing of rice gruel, still more, rice gruel and steam can be distinguished securely.
In the rice cooker of the invention, preferably, the control means has an operation unit for instructing selection of rice cooking function, and is constituted so as to inhibit input of operation signal from the operation unit for a specific time after the lid is closed. As a result, malfunction in opening and closing of lid can be prevented securely. Preferably, an input switch of high frequency of manipulation should be disposed ahead of the top of the lid. As a result, malfunction in closing of lid can be avoided more effectively.
In the rice cooker of the invention, the rice gruel detecting means comprises a float and a float detecting unit, and the moving portion of the float should preferably has a slope of 5° to 15° in the case of expansion or contraction of the rice gruel generated in the inner pan. Hence the float rolls over the rice gruel. Preferably, the passage of rolling of the float is provided in a steam path of nearly tubular form in a steam tube disposed in the lid, the outline of the float is circular, grooves are provided in upper and lower sides of the steam path, the float and the lateral side of the steam path are formed so as not to contact with each other, a clearance between the steam path and the float is provided widely in the upper part of the float, blow outlets of the steam path are disposed at the lateral side and lower side, and the sectional area of the clearance of the steam path and the float is defined at about 60 to 90 mm 2 when the weight of the float is 2 to 4 g. Therefore, in a simple constitution, the float is not moved by the steam, but is moved by passing of the rice gruel, so that the rice gruel and steam can be distinguished securely. Also preventing dull action due to surface tension of the float and steam path lateral side, the float rolls easily and moves smoothly.
In the rice cooker of the invention, the steam tube is provided detachably in the lid, and the steam path in the float sliding portion can be cleaned easily. The float is made of a magnetic member having an elastic material such as rubber on the surface, and the impact of moving of the float is lessened, and therefore crack or cut of the float can be prevented, and the moving noise can be lowered. Moreover, a slope is provided in the bottom of the steam tube, and the lower end of the slope is provided at a higher position than the upper opening of the steam path, and therefore reflux valve of rice gruel is not necessary in the bottom of the steam tube, so that the constitution may be simplified.
In the rice cooker of the invention, preferably, the lid has a float detecting unit composed of a lead switch near the steam tube and at the front side of the main body, the steam path is formed so as to incline downward to the float detecting unit, a flange is provided in the rear part of the steam tube so as to be mounted on the lid only in one direction, the control means has an operation unit for instructing selection of rice cooking function, and the operation unit is constituted to inhibit input of operation signal when the steam tube is not mounted on the lid, or the lid is open. Therefore, malfunction can be prevented securely when the steam tube is not mounted or when the lid is open.
Preferably, the float detecting unit is designed to detect presence or absence of move of the float at a position moving about 1⅓ of the moving distance of the float on the slope or in the steam path. Therefore, if the rice gruel is weak when cooking a small amount of rice, rice gruel can be detected securely. Or, by using a lead switch in the float detecting unit, and forming the lead switch in a V-form along the steam tube, the detecting precision of the float detecting unit can be enhanced.
In the rice cooker of the invention, the steam vent on the top of the steam tube is formed obliquely above and in the rear direction of the main body, so that the steam is exhausted to the back side of the main body. As a result, dew condensation of steam and drop of splashes on the operation unit disposed ahead of the lid can be prevented.
In the rice cooker of the invention, preferably, a hinge for supporting the main body and the lid by the shaft is provided in the rear part of the main body, and a steam vent is preferred to be disposed ahead of the main body on the steam tube. Therefore, drop of water drops by dew condensation in the steam tube when opening the lid to outside of the steam tube can be prevented.
In the rice cooker of the invention, upper frame caps for supporting the inner pan provided at three equal positions on the top of the main body, and locking rubber pieces for positioning the inner pan provided at three equal positions in the center of the inner circumference of the protective frame are alternately disposed so as to form an angle of 60°. As a result, the inner pan can be held uniformly, and set position deviation of the inner pan into the main body can be decreased.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of a rice cooker in a first embodiment of the invention.
FIG. 2 is a sectional view of steam tube of this rice cooker.
FIG. 3 is a sectional view showing essential parts of this steam tube.
FIG. 4 is a sectional view showing a steam path of this steam tube.
FIG. 5 is a schematic view of float detecting unit and surrounding seam tube of this rice cooker.
FIG. 6 is a schematic view of the top of the lid of this rice cooker.
FIG. 7 is a schematic perspective view of rice gruel detecting means of a rice cooker in a second embodiment of the invention.
FIG. 8 is a schematic perspective view of rice gruel detecting means of a rice cooker in a third embodiment of the invention.
FIG. 9 is a power control diagram of this rice cooker.
FIG. 10 is other power control diagram of this rice cooker.
FIG. 11 is a top view of appearance of essential parts near the inner pan accommodating area of a rice cooker in a fourth embodiment of the invention.
FIG. 12 is a longitudinal sectional view of a conventional rice cooker.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, preferred embodiments of the invention are described in detail below.
Embodiment 1
A first embodiment of the invention is described by referring to FIG. 1 to FIG. 4 . As shown in these diagrams, in the first embodiment, boiling-over is prevented by a sensor in the steam tube, and the rice cooker is easier to use. That is, to keep low the height of a lid 36 , a steam tube 47 is also lower in the longitudinal direction than in the prior art, and the function for detecting rice gruel and the function for detecting opening and closing of the lid 36 are combined.
More specifically, the steam tube 47 incorporating a float 48 movable when opening or closing the lid 36 , and a float detecting unit 49 for detecting move and presence or absence of the float 48 are disposed ahead of the main body around the steam tube 47 , and by making use of the move of the float 48 to the hinge 38 side when the lid 38 is opened, opening or closing of the lid 36 is detected, while detaching or attaching of the steam tube 47 is detected by the presence or absence of the float 48 .
As shown in FIG. 2 to FIG. 4, the float 48 is, when the lid 36 is closed, disposed so as to cover the top of a blow outlet 68 of steam, and the float 48 is formed of a magnet in cylindrical or spherical form, that is, in a shape small in contact resistance. On the other hand, the steam tube 47 is provided with a steam path 70 keeping a wide clearance at the upper side of the float 48 , and the float 48 is formed so as to move in the steam path 70 . In an upper inner side 70 a and a lower inner side 70 b of the steam path 70 , grooves 67 for guiding the move of the float 48 are provided, and the float 48 has a convex portion 48 a to be guided along the recessed grooves 67 provided along the enter circumference of the float 48 .
The rice gruel blow outlet 68 of the steam path 70 is disposed not only in the bottom but also in the lateral side, so that the float 48 is easy to roll by the steam pressure from the lateral side. The groove 67 forms a passing route for rice gruel, and also prevents impossibility of move of the float 48 due to rice gruel.
Concerning the constitution of the float 48 , for example, by using a magnetic material for the float 48 , a lead switch 49 a is used in the float detecting unit 49 , or, as mentioned later, a photo sensor is used in the float detecting unit 49 , so that the presence of the float 48 may be detected by the presence or absence of its reflection. Anyway, however, the float 48 is defined by the weight of the float itself not to be moved by steam but to be moved along with rise of the rice gruel, inclination angle of the slope 47 a of the bottom of the steam tube 47 , and the clearance between the steam path 70 and float 48 . The relation between the weight and the rice gruel was experimentally disclosed as follows: by using a columnar float (14 mm in diameter, 10 mm in width), when the sectional area of the clearance of the float 48 and steam path 70 is about 75 square millimeters (mm 2 ), and the angle of the bottom slope 47 a is about 12°, the weight of about 2 to 4 grams (g) is suitable for adequate action to rise of rice gruel when boiling over in the rice cooking process. In this condition, it was confirmed that the operation is secure without malfunction in the range of the sectional area of the clearance of 60 to 90 mm 2 and the bottom angle of about 5 to 15°.
Further, in the lower part of the steam tube 47 , by forming a slope 47 b in the upper part of the steam path 70 , the rice gruel collected in the steam tube 47 refluxes into the inner pan 32 through the steam path 70 . Therefore, reflux valve is not needed at the lower side of the steam tube 47 . Although the inner volume of the steam tube 47 is small for compact design, by detecting the move of the float 48 by the float detecting unit 49 , power supply to the heating element (heating means) is controlled depending on the detection result. In this embodiment, since it is designed to control supply of high frequency power to the bottom heating coil 33 a , the steam tube 47 of smaller space than in the prior art can be used. That is, along with the rise of the rice gruel in the steam path 70 , the rice gruel is collected in the lower part of the float 48 and the steam path 70 is clogged, and the internal pressure climbs up, the float 48 moves, and the float detecting unit 49 detects the move of the float 48 , so that the above effects are obtained.
At this time, the internal pressure of the rice gruel clogging the steam path 70 is about 2 to 3 cm on water column in this constitution, and there is no risk of deformation of the lid by high pressure.
In this embodiment, the difference between rice gruel and steam is detected by the motion of the float, but this detection may not depend on the dynamic motion, but may be realized by making use of physical difference such as viscosity of rice gruel or thermal capacity.
Moreover, in order to avoid breakage of the internal parts of the float 48 , steam tube 47 and steam path 70 due to sudden move of the float 48 by sudden opening or closing of the lid 36 , the surface of the float 48 is covered with buffer material 69 such as rubber or other elastic member or synthetic resin, and it is reinforced by disposing a rib at the side of the steam tube 47 near the end point of the move of the float 48 . In this constitution, breakage of steam tube 47 , steam path 70 and float 48 can be prevented, and since the float 48 is covered with an elastic member, moving noise of the float 48 may be suppressed low.
As shown in FIG. 5 and FIG. 6, the steam tube 47 can be detached and washed by the user same as in the prior art, but in order that the float 48 when mounting the steam tube 47 and the float detecting unit 49 may always confront, at the opposite side of the float detecting unit 49 , a flange 71 is disposed on the top of the steam tube 47 and a recess 72 corresponding to the flange 71 is disposed on the lid 36 , so that detachability of the steam tube 47 and detecting precision of rice gruel can be assured, and the front operation unit 73 can be formed widely. Moreover, since the blow outlet 68 is provided at the lowest position of the bottom, the water after washing hardly remains within the steam tube 47 , and the cleanliness can be maintained.
The float detecting unit 49 detects move of the float 48 at a point of short moving distance of rising of about ⅓ of the moving distance (slope) of the float 48 in the steam path. 70 , and therefore rice gruel can be detected even in the case of soft rice cooking course or soup rice cooking course by small amount and low heat.
As shown in FIG. 5, the lead switch 49 a for composing the float detecting unit 49 is accommodated in a lead switch case 49 b , and it is fixed as being filled with elastic member such as silicone rubber, and is disposed near the steam tube 47 . The lead switch 49 a is easier to detect as the magnetic force of the magnet is stronger or the distance to the magnet is shorter, but as the lead switch 49 a is formed nearly in a V-form, the distance of the float 48 and lead switch 49 a is shortened, and the detecting precision of the lead switch 49 a is enhanced, and the rice gruel can be detected more securely.
As shown in FIG. 1 and FIG. 2, by forming the steam vent 74 backward of the main body 31 with the opening direction obliquely upward, disposing at the front side of the main body on the top of the steam tube 47 , the steam generated while cooking rice can be exhausted backward of the main body 31 . As a result, dew condensation and drop of splashes on the operation unit 73 disposed in the lid 36 can be prevented, and water drops of dew condensation in the steam tube 47 are prevented from dropping out of the steam tube 47 when opening the lid 36 .
Opening or closing of the lid 36 is detected as the float 48 provided inside the steam tube 47 departs from the float detecting unit 49 when the lid 36 is opened, but when closing the lid 36 , it may be also considered to close by pressing down the upper part of the lid 36 . On the other hand, in the upper part of the lid 36 , an operation board (control board) 42 is provided, and it may be likely that the lid 36 is closed while pressing an operation button by mistake. Accordingly, for a specific time after closing of the lid 36 , key input accepting on the operation board 42 is inhibited, and unintended manipulation of the user is inhibited. At this time, in order that the user can easily know the reason why key operation is not accepted, it is indicated in a display unit 75 . In the operation board 42 used as the control means, the display unit 75 is provided, and an input switch 76 is incorporated therein.
If the lid 36 is closed by mistake, assuming that the lid 36 is being pressed for a long time, the key of which execution is hard to understand for the user, for example, the rice cooking course selection key 76 a is disposed away from the front central area. On the other hand, in case key operation is accepted, the cooking start key 76 b or other key of which acceptance is relatively easy to understand for the user is disposed in the upper front part of the lid 36 , at a position easily pressed by the user when closing the lid 36 .
As mentioned herein, the rice gruel detector makes use of move of the float when opening or closing the lid, or due to expansion or contraction of rice gruel generated in the pan, and rice gruel can be detected in a simple constitution. Besides, a slope is provided in the bottom of the steam tube, and the float is formed of columnar or spherical ferrite disposed so as to be free to roll over the slope, and the float detecting unit is formed of a lead switch, so that the structure of the float may be suited to detection of rice gruel.
Embodiment 2
A second embodiment is described below. In FIG. 7, reference numeral 79 shows the inside of the steam tube 47 . A hole 80 is provided at the lower side of the steam tube 47 , and a hole 81 is formed at the upper side. The rice gruel passes through the hole 80 at the lower side, and further passes between an emitter 82 and a detector 83 of photo sensor, and goes up. At this time, the light is shielded and the rice gruel detector functions, and power supply to the inner pan 32 is stopped. By this stopping, for example, in the case of induction heating (IH), generation of rice gruel disappears soon. By the rice gruel detecting means of such constitution, boiling-over can be prevented.
Embodiment 3
A third embodiment is described. In this embodiment, instead of the photo sensor in embodiment 2, a pair of electrodes are provided. In FIG. 8, when the rice gruel passes through the hole 80 at the lower side and is collected between a pair of electrodes 84 , 84 , a current flows between the electrodes 84 , 84 . By detecting this current, boiling-over can be prevented same as in embodiment 2.
Besides, for example, a PTC heater for detecting temperature change by evaporation heat is provided in a passage of rice gruel, and it may be used as rice gruel detecting means.
In the constitution having the rice gruel detecting means provided in the lid, for example, by disposing the rice gruel detecting means in the steam tube, mounting is easy and cleaning is easy, and clean rice gruel detecting means can be composed. Moreover, by disposing the rice gruel detecting means in the passage of rice gruel, for example, in the upper part of the inner pan 32 , easy-to-clean rice gruel detecting means is obtained.
As shown in FIG. 9 and FIG. 10, when rice gruel is generated, power supply to the inner pan 32 is stopped by a signal from the rice gruel detecting means. On the other hand, when generation of rice gruel is stopped, the float 48 returns to the initial position, and by detecting it, power supply to the inner pan is resumed, so that the power supply to the inner pan may be always full power. Thus, by turning on and off the power supply to the inner pan by detecting generation of rice gruel, rice and water can be sufficiently heated when cooking, so that tasty rice can be cooked.
Embodiment 4
The structure around the accommodating part of the inner pan 32 is described by referring to FIG. 1 and FIG. 11 . The inner pan 32 is accommodated in a protective frame 85 disposed in the main body 31 . The accommodated inner pan 32 is supported by upper frame caps 86 disposed at three equal positions at the upper end of the protective frame 85 , and positioned by pan locking rubber pieces 87 disposed at three equal positions in the center of the inner circumference of the protective frame 85 . Herein, the upper frame caps 86 and pan locking rubber pieces 87 are alternately disposed at an angle of 60°. In this constitution, the inner pan 32 is accommodated in the protective frame 85 without bias, and the distance of the inner pan 32 and bottom heating coil 33 a is uniform in all parts, and therefore generation of local strong bubbling rice gruel in the inner pan 32 is decreased, and rise of rice gruel into the steam tube 47 is reduced.
The invention is not limited to those illustrated embodiments, and various changes and modifications are possible. All modifications existing within the scope or true spirit of the invention are included in the scope of the claims of the invention. | A compact rice cooker with excellent rice cooking performance while preventing boiling-over is presented. This rice cooker includes a main body 31, a lid for covering the top of the main body, an inner pan detachably accommodated in the main body, a bottom heating coil for induction heating of the inner pan, a control unit for controlling high frequency power to be supplied to the bottom heating coil, and a rice gruel detecting unit disposed in a steam tube of the lid, and therefore electric power supply is controlled by the control unit depending on the detection state by the rice gruel detecting unit. The rice gruel detecting unit makes use of movement of the float due to the rise of rice gruel, and the lid is formed in a compact size, and boiling-over is prevented, so that tasty rice can be cooked. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to new and useful containers for precursor materials used as source materials in atomic layer deposition (ALD) or metalorganic chemical vapor deposition (MOCVD) processes and to methods related thereto.
BACKGROUND OF THE INVENTION
[0002] Atomic layer deposition (ALD) is an enabling technology for next generation conductor barrier layers, high-k gate dielectric layers, high-k capacitance layers, capping layers, and metallic gate electrodes in silicon wafer processes. ALD has also been applied in other electronics industries, such as flat panel display, compound semiconductor, magnetic and optical storage, solar cell, nanotechnology and nano materials. ALD is used to build ultra thin and highly conformal layers of metal, oxide, nitride, and others up to one monolayer at a time in a cyclic deposition process. Oxides and nitrides of many main group metal elements and transition metal elements, such as aluminum, barium, cerium, dysprosium, hafnium, lanthanum, niobium, silicon, strontium, tantalum, titanium, tungsten, yttrium, zinc and zirconium have been produced by ALD processes using oxidation or nitridation reactions. Pure metallic layers, such as Ru, Cu, Ti, Ta, W, and others may also be deposited using ALD processes through reduction or combustion reactions.
[0003] A typical ALD process is based on sequential applications of at least two precursors to the substrate surface with each pulse of precursor separated by a purge. Each application of a precursor is intended to result in up to a single monolayer of material being deposited on the surface. These monolayers are formed because of the self-terminating surface reactions between the precursors and surface. In other words, reaction between the precursor and the surface should proceed until no further surface sites are available for reaction. Excess precursor will not react with same type of precursor that has already reacted at the surface site and the excess precursor is then purged from the deposition chamber. Following the purge, the second precursor is introduced and reacts with the first precursor on the surface. Any excess second precursor is purged after surface saturation. Each precursor pulse and purge sequence comprises one ALD half-cycle that theoretically results in up to a single additional monolayer of material. Because of the self-terminating nature of the process, even if more precursor molecules arrive at the surface, no further reactions will occur. It is this self-terminating characteristic that provides for high uniformity, conformality and precise thickness control when using ALD processes.
[0004] Chemical vapor deposition (CVD) is a chemical process used to produce high-purity, high performance solid materials, particularly in the semiconductor and microelectronic industries for the production of thin films with greater growth rates than ALD processes. A typical CVD process comprises exposing a wafer to one or more volatile precursor materials that react or decompose on the wafer surface to produce the desired layer deposit continuously. Volatile by-products are usually produced that must be removed by gas flow through the reaction chamber. CVD is used in a wide variety of forms, including metalorganic chemical vapor deposition (MOCVD) to deposit materials such as monocrystalline, polycrystalline, amorphous and epitaxial layers of silicon, carbon fiber, carbon nanofibers, filaments, carbon nanotubes, silicon dioxide, silicon germanium, tungsten, silicon carbide, silicon nitride, silicon oxynitride, titanium nitride, high-k dielectrics, etc. MOCVD techniques are based upon the use of metalorganic precursor materials for the formation of the desired layers.
[0005] There are a wide variety of precursor materials that can be used in ALD and MOCVD processes. For example, new solution based precursors have been proposed in Published US patent application 2006-0269667, hereby incorporated in its entirety by reference. These solution based precursors allow greater choice in precursor materials and because they are comprised of a dissolved metal precursor in a solvent mixture, can also enhance chemical utilization and reduce costs.
[0006] In particular, disclosed in the above published patent application are precursor solutions comprised of one or more low volatility precursors (including solid precursors) dissolved in a solvent. For example, the precursor may be a halide, alkoxide, β-diketonate, nitrate, alkylamide, amidinate, cyclopentadienyl, or other organic or inorganic metal or non-metal compound. More specifically, the precursor may be Hf[N(EtMe)] 4 , Hf(NO 3 ) 4 , HfCl 4 ,HfI 4 , [(t-Bu)Cp] 2 HfMe 2 , Hf(O 2 C 5 H 11 ) 4 , Cp 2 HfCl 2 , Hf(OC 4 H 9 ) 4 , Hf(OC 2 H 5 ) 4 , Al(OC 3 H 7 ) 3 , Pb(OC(CH 3 ) 3 ) 2 , Zr(OC(CH 3 ) 3 ) 4 , [(t-Bu)Cp] 2 ZrMe 2 , Ti(OCH(CH 3 ) 2 ) 4 , [(t-Bu)Cp] 2 TiMe 2 , [(i-Prop)Cp] 3 La, Ba(OC 3 H 7 ) 2 , Sr(OC 3 H 7 ) 2 , Ba(C 5 Me 5 ) 2 , Sr(C 5 i-Pr 3 H 2 ) 2 , Ti(C 5 Me 5 )(Me 3 ), Ba(thd) 2 *triglyme, Sr(thd) 2 *triglyme, Ti(thd) 3 , RUCP 2 , Ta(NMe 2 ) 5 or Ta(NMe 2 ) 3 (NC 9 H 11 ). The concentration of the precursor in the precursor solution is generally from 0.01 M to 1 M and the precursor solution may include stabilizing additives with concentrations from 0.0001 M to 1 M, such as oxygen containing organic compounds, e.g. THF, 1,4-dioxane, or DMF. The solvent used has a boiling point selected to ensure no solvent loss during vaporization. In particular, the solvent may be dioxane, toluene, n-butyl acetate, octane, ethylcyclohexane, 2-methoxyethyl acetate, cyclohexanone, propylcyclohexane, 2-methoxyethyl ether(diglyme), butylcyclohexane or 2,5-dimethyloxytetrahydrofuran. Specifically disclosed precursor solutions include aluminum i-propoxide dissolved in ethylcyclohexane or octane; [(t-Bu)Cp] 2 HfMe 2 dissolved in ethylcyclohexane or octane; Tetrakis(1-methoxy-2-methyl-2-propoxide)hafnium (IV) dissolved in ethylcyclohexane or octane; hafnium tert-butoxide or hafnium ethoxide dissolved in ethylcyclohexane or octane; a mixture of Ba(O-iPr) 2 , Sr(O-iPr) 2 , and Ti(O-iPr) 4 dissolved in ethylcyclohexane or octane; and RuCp 2 dissolved in dioxane, dioxane/octane or 2,5-dimethyloxytetrahydrofuran/octane.
[0007] Further solution based precursors are disclosed in pending U.S. patent application Ser. No. 12/261,169, hereby incorporated in its entirety by reference. This application discloses precursors comprising lanthanum alkyl cyclopentadienyl compounds. Specific examples of such compounds include lanthanum(III)isopropoxide; tris(N,N-bis(trimethylsilyl)amide)lanthanum; tris(cyclopentadienyl)lanthanum; or tris(isopropyl-cyclopentadienyl)lanthanum.
[0008] These solution based precursors are delivered by direct liquid injection (DLI) methods, which means the precursor liquid can remain at ambient temperature, thereby providing long stability and dosage control. The solution precursor is vaporized in a vaporizer before deliver to the process chamber. When a standard liquid precursor container is used as the container for the source material precursors, the liquid material is pushed into the DLI system through a dip-tube by head-space gas pressure. The liquid precursor in pure chemical form or the dissolved metal precursor in solution form might disadvantageously interact with downstream DLI metal surfaces, such as particle filters, liquid mass flow controllers, valves, and pipes to form thin film layers on the surfaces thereof. If such interaction occurs, particles could form from the adsorbed metal complex when the DLI system pressure and temperature change. In addition, air and moisture contamination during the source change or system service may promote unwanted surface reactions to form thin film or particles. This thin film and particle formation leads to problems with the DLI system, particularly, making it difficult to control liquid flow, and eventually causing system clogging.
[0009] The source condensed film or absorbed metal organic precursors cannot be purged out of the system with inert gases and vacuum cycles because of the surface bonding that occurs. Therefore, removal of surface molecules generally requires washing and dissolving in a cleaning solvent before purge with air or moisture. Such a system requires additional piping be included in the standard DLI system or disconnection of the precursor source container to enable cleaning.
[0010] Therefore, there remains a need in the art for improvements to the use of liquid based precursors in ALD and MOCVD processes.
SUMMARY OF INVENTION
[0011] The present invention provides new and useful containers for precursor materials that are used as source materials in ALD or MOCVD processes. In particular, one solution to alleviate problems related to the build up of thin films or particles in the DLI system is to perform pre-cleaning and post-cleaning of the DLI system using a rinse by a solvent or solvent mixture that is the major component of the solution-based precursor material. Such a solvent or solvent mixture can re-dissolve surface adsorbed metal complexes in the DLI system. The solvent or solvent mixture can also be used to clean absorbed metalorganic precursors from downstream surfaces when using pure ALD or MOCVD precursor sources.
[0012] However, because of limited working space, the use of a source container, additional piping and a separate container for holding rinse solvent, is impractical. Therefore, the present invention provides a new container for holding both the precursor liquid and the rinse solvent that will fit within the available space.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a cut away plan view of a container for precursor source material and solvent rinse in accordance with one embodiment of the present invention.
[0014] FIG. 2 is a three dimensional view of a container for precursor source material and solvent rinse in accordance with one embodiment of the present invention.
[0015] FIG. 3 is a three dimensional cut away view showing the interior of a container for precursor source material and solvent rinse in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The present invention will be described in detail with reference to the drawing figures. In particular, FIG. 1 , is a schematic view of the container system according to a first embodiment of the present invention, and shows a container system 100 , that holds both a precursor source solution and a solvent rinse separately. The system 100 , includes a container 10 , having two separate chambers defined by an outer wall 12 , and an inner wall 14 . The container 10 , can be of any desirable shape or size, but preferably is cylindrical in shape and sized to fit within the existing space of a fabrication area. For example, the outer wall 12 , may be defined by a first cylinder of a first diameter and the inner wall 14 , may be defined by a second cylinder having a second diameter smaller than that of the first cylinder, such that the second cylinder fits concentrically or in an offset manner within the first cylinder. The two cylinders are welded to two planer circular disks having a diameter equal to the diameter of the first cylinder and arranged so as to provide a top 16 , and bottom 18 , for the container 10 .
[0017] By constructing the container 10 , in the manner described above, two chambers are formed. In FIG. 1 , the innermost chamber is used to contain a liquid precursor or precursor solution 20 (hereinafter referred to as precursor solution 20 ) and the outermost chamber contains solvent rinse 25 . The volume ratio of precursor solvent rinse to precursor solution can range from ten percent (10%) up to one hundred percent (100%) depending on the desired manufacturing application. It is also possible to reverse the location of the solutions, i.e. the precursor solution can be in the outermost chamber and the solvent rinse in the innermost chamber.
[0018] Either of the precursor solution 20 , or the solvent rinse 25 , can be delivered to a DLI system 30 , through the use of dip tubes and the maintenance of head pressure within the two chambers of the container 10 . In particular, a precursor solution dip tube 40 , equipped with an optional particle filter 42 , is located in the inner chamber of the container 10 , submerged within the precursor solution 20 . Further, a rinse solvent dip tube 50 , equipped with an optional particle filter 52 , is located in the outer chamber of container 10 , and submerged within the rinse solvent 25 . The precursor solution dip tube 40 , and the rinse solvent dip tube 50 , each provide their respective solutions to the DLI system 30 , through appropriate piping and valves. In particular, a three way valve system can be employed so that the supply of appropriate solution can be switched as needed for processing, i.e. precursor solution 20 , will be supplied to the DLI 30 , during a deposition stage, and rinse solvent 25 , will be supplied to the DLI 30 , during a cleaning stage. Optional check valves can be included for added control and to prevent back flow to the container 10 . The dip tubes, connection piping and valves can be constructed of any inert material, preferably electro-polished stainless steel.
[0019] Head pressure is maintained within the two chambers of the container 10 , by providing an inert gas to the head space in each chamber. In particular, an inert gas source 35 , provides inert gas, such as nitrogen, argon or helium, through appropriate piping and valves to the head space of both the inner chamber and the outer chamber of the container 10 . Optional check valves can be used to prevent back-flow of the solutions. Alternatively, a three way valve can be employed to isolate separate ports for introduction of the inert gas to the head space areas. In addition, a connection can be provided between the piping and valve system for delivery of the solutions to the DLI 30 , and the piping and valve system for delivery of the inert gas. This connection allows inert gas to be supplied to the DLI 30 , as a purge gas. In addition, cleaning solution can be provided through this connection for cleaning of the system. The connection piping and valves can be constructed of any inert material, preferably electro-polished stainless steel.
[0020] The container 10 , is also provide with filler ports 70 , 72 , that allow for additional solution to be provided to the different chambers of the container 10 . In particular, additional precursor solution can be added to the inner chamber through filler port 70 , and additional rinse solvent can be added to the outer chamber through filler port 72 . Optionally, each chamber of the container 10 , can have a level sensor to measure the liquid level of the solution in the chamber. In particular, level sensor 80 , can be used to measure the liquid level of the precursor solution in the inner chamber, and level sensor 82 , can be used to measure the liquid level of the rinse solvent in the outer chamber.
[0021] FIGS. 2 and 3 show further views of the container according to the present invention. In particular, FIG. 2 is a three dimensional view showing the container for precursor source material and solvent rinse according to the present invention. FIG. 3 is another three dimensional view that has been cut away to show the interior of the container for precursor source material and solvent rinse according to the present invention.
[0022] The system 100 , of the present invention would operate as follows. Prior to deposition processing, the container would be filled with precursor solution 20 , and rinse solvent 25 . Desired liquid levels could be set by using the optional level sensors 80 , 82 . The head space in both chambers of the container 10 , could then be pressurized by flowing inert gas from the inert gas source 35 , into the two chambers through the piping and valves. The piping and valve system for the solutions would then be set to provide rinse solvent 25 , from the rinse solvent dip tube 50 , to the DLI system 30 . This serves to pre-clean the DLI system 30 . The piping and valve system would then be set to provide precursor solution 20 , from the precursor solution dip tube 40 , to the DLI system 30 , for use in carrying out the desired deposition process. After the initial deposition stage, the system can again be rinsed with rinse solvent 25 , by resetting the valves to provide rinse solvent 25 , through the rinse solvent dip tube 50 , to the DLI system 30 . This rinse serves to re-dissolve any liquid precursor that has adhered to piping and other surfaces and then to remove such along with particles or thin films that may have built up from the precursor solution 20 , during the deposition stage, from the system. The process can then continue in similar fashion, switching as desired between precursor solution 20 , delivery and rinse solvent 25 , delivery to the DLI system 30 .
[0023] The system of the present invention provides several advantages. In particular, this system allows for the pre-cleaning of the DLI system using pure rinse solvent (or solvent mixture) before deposition processes begin. Further, calibration and check of liquid flow rates can be carried out using the rinse solvent. In addition, the DLI system can be cleaned at the end of the deposition process or when the chemistry or deposition process parameters change. The system of the present invention provides a compact design that minimizes the need for additional space and connection piping. Moreover, the system of the present invention includes minimum dead space that cannot be cleaned with rinse solvent.
[0024] It is anticipated that other embodiments and variations of the present invention will become readily apparent to the skilled artisan in the light of the foregoing description, and it is intended that such embodiments and variations likewise be included within the scope of the invention as set out in the appended claims. For example, many different piping and valve arrangements can be utilized without departing from the invention. Further, virtually any arrangement of the container and chambers within the container is possible. For example, a cylinder within cylinder arrangement that requires only a single inert gas feed for pressurization of the head space for both chambers is possible. | Precursor source containers to hold precursor materials used in thin film deposition processes, such as ALD and MOCVD methods are described. In particular, the container holds both a liquid precursor or a dissolved precursor solution and a rinse solvent in separate chambers, and reduces the overall space requirement. In one embodiment, a cylinder within a cylinder arrangement provides two separate chambers, one for the precursor solution and the other for the rinse solvent. | 2 |
FIELD OF THE INVENTION
This invention pertains to methods and apparatus for obtaining improved CT images employing apparatus and methods which simulate the geometry of an X-ray therapy machine.
CROSS-REFERENCED APPLICATIONS
Reference is made to the following copending U.S. Patent Applications, owned by the assignee of this invention, which are incorporated herein by reference. This is a continuation-in-part of the following applications:
(1) "Computed Tomography Apparatus using Image Intensifier Detector", Ser. No. 07/547,450, filed Jul. 2, 1990.
(2) "Electronically Enhanced X-ray Detector", Ser. No. 07/547,449, filed Jul. 2, 1990.
(3) "Method for Improving the Dynamic Range of an Imaging System", U.S. Pat. No. 5,168,532.
(4) "Method for Increasing the Accuracy of a Radiation Therapy Apparatus", U.S. Pat. No. 5,099,505.
(5) "Partial Fan Beam Tomographic Apparatus and Data Reconstruction Method", Ser. No. 07/547,596, filed Jul. 2, 1990.
BACKGROUND OF THE INVENTION
Computed tomography scanners (CT) are not well known for providing cross sectional slice X-ray images of a sample. X-rays are made to transit through the sample from various directions and to impinge on a detector so that the detector is responsive to those X-ray photons which are not absorbed. The geometric relationship between the X-ray source and the detector is fixed so that the paired source and detector can be rotated with the sample or patent near the center of rotation while a new set of data is taken at many angular positions around the sample. The data is processed by a high speed computer using known algorithms to provide a reconstruction of the matrix of the density function of the sample with the ability to display this density function in selective planes or slices across the sample.
Diagnosticians study such cross sectional images and can non-invasively evaluate the sample, such as a cancer patient.
In early CT apparatus, the images were frequently blurry, primarily due to the breathing or other movement of the patient during scanning. Several improvements overcome these problems in standard diagnostic CT. Specifically, high power X-ray tubes were developed which made possible higher speed scanning at adequate dose for imaging. This reduced the amount of patient movement between adjacent slices. Additionally, faster and improved algorithms capable of direct fan beam reconstruction without reordering, made real time imaging a meaningful reality. However, these standard diagnostic CT scanners are not optimum for planning radiation therapy for cancer patients. Because high levels of radiation are to be used in treating a cancer patient, it is extremely important that the therapists be able to precisely locate sites of interest for planning and treating. However, the standard diagnostic CT scanner does not configure the patient in exactly the same relationship to the X-ray source as in the radiation therapy machine. Specifically, the position of organs are not the same in the two instruments and this introduces a difficulty in using standard CT Scanners for Radiation Therapy Planning.
Because of this problem, another class of X-ray planning device has become known, called a Simulator. As the term implies, the Simulator is a radiographic/fluoroscopic X-ray device which is shaped and outfitted to simulate the geometry of a radiation therapy treatment machine so that the images formed on the simulator can be interpreted more precisely in terms of the therapy machine. These simulator machines have traditionally been less expensive instruments and did not provide CT scanner capability. As described in the patent applications listed above as CROSS REFERENCED APPLICATIONS, a quality CT scanner capability is now available in simulators as well as in diagnostic CT. However, one major distinction between the CT simulator as compared to the standard diagnostic CT scanner is that the simulator was built to mimic the radiation therapy accelerator and like the radiation therapy accelerator is not capable of high speed scanning. For example, a diagnostic CT scanner X-ray source and detector complete a scan of a 360 degree rotation in about 1-2 seconds. In contrast, the Radiation Therapy Simulator takes about 60 seconds to complete one scan. This is close to the treatment exposure time. This is close to the treatment exposure time. However, because the Simulator scan rate is slower, movement of the patient between and during slices can cause significant deterioration of the data. Also, in order to obtain sufficient patient data for analysis it is not unusual to require as many as ten slices. At a minimum due to patient repositioning and scan processing this requires thirty minutes with the patient required to remain in frequently uncomfortable position for the entire time.
SUMMARY OF THE INVENTION
It is an object of this invention to minimize deterioration effects of patient movement on X-ray scanner data in an X-ray Therapy Simulator.
It is still a further object to increase the rate of data taking in a Radiation Therapy Simulator to shorten total patient time of discomfort during treatment planning.
It is a further object to provide a Radiation Therapy Simulator with improved three dimensional CT having improved point spread correction functions.
It is a feature of this invention to provide n simultaneous fan beams and 2n+1 simultaneously operating array detectors.
It is a still further object to provide this invention as an accessory for use with Radiation Therapy Scanners so that all of the important features and capabilities of those instruments can be retained while relatively inexpensively adding the benefits of volumetric scanning where breathing and other patient motions are correlated across a large number of images.
It is a still further object to provide an instrument and method which enables improved calculation and prediction of dose and dose configuration for radiation therapy.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is prospective view of a Radiation Therapy Simulator;
FIG. 2 is a block diagram of the inventive system;
FIG. 3A is a side view of an embodiment of a multiple fan beam X-ray target anode used in this invention.
FIG. 3B is a front view of an embodiment of a multiple fan beam X-ray target anode and pre and post collimators;
FIG. 4 is a detail of the front view of the relationship of the X-ray target anode and the pre and post collimator;
FIG. 4A is a detail of section AA of FIG. 3;
FIG. 4B is a detail of section BB of FIG. 3;
FIG. 5 is a drawing of an X-ray tube having multiple filaments.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, a portion of a prior art Radiation Therapy Simulator, assigned to the same assignee, is described in the References Applications cited above. The gantry is comprised of a drive unit 10 of welded steel fabrication which is bolted to a base which is cast into the floor. In the drive structure 10 is a mechanism for driving the rotating arm 12 with precision around the isocenter axis 2. On the arm 12 are mounted the carriages 14 and 16 for the X-ray head assembly 18 and image assembly 24 including an image intensifier 20, an imaging extension detector 45 mounted slightly obliquely to the image intensifier, a flip mirror assembly 42 for selectively providing the output from the image intensifier to the photodiode linear array 44 or to the television camera 56. In the X-ray head 18 is a high voltage generator in conjunction with a double focus (0.6 mm and 1 mm) X-ray tube containing a lead bladed collimator which can be manually adjusted. Also included in the prior art X-ray head is a motorized cross wire assembly. The treatment couch 26 includes a steel framework supported on a large precision bearing ring mounted into the floor. The frame carries a telescopic ram assembly 28 for the couch 26, and slides 27 for longitudinal movement of the patient as well as a sub chassis for lateral movement.
The above prior art Simulator provided a computerized tomography capability and is more fully shown in FIG. 5 of the copending application Ser. No. 07/547,451 (90-33), referenced above. This prior system, is capable of quality CT scans which are close to the quality of those produced by the very much more expensive and faster diagnostic CT scanners. However, because of the fact that the gantry of the radiation therapy simulator is rotated much more slowly around the patient, i.e. 60 sec vs. 3 second, the breathing and/or movement of the patent causes blurring of the images.
FIG. 2 illustrates schematically the elements of our inventive simulator improvement to minimize the image blurring due to sample or patient movement. We have provided a modified X-ray source tube, 50 in FIG. 5, having a rotating anode 61 having and a large number of filaments, to produce simultaneously X-ray source spots, 61-1 through 61-7, FIG. 2, FIG. 3B and FIG. 4. The X-ray source tube has the same number of separate filaments, FIG. 5, 100-1 though 100-7, as separate source spots. The required close spacing of the filaments in the tube, i.e., 1.5 cm on center, limits the number of filaments. In this embodiment, seven X-ray fan beams are generated simultaneously, 67-1 through 67-7. The fan beams are shaped by precollimator 88, FIG. 2, and post collimator 89 which are described more fully subsequently. The plurality of fan beam 67-1 through 67-7 fall on the image intensifier tube (IIT) 65 and imaging extension 2-D detector array preferably made from a cadmium tungstate scintillator.
In the simulator of copending application Ser. No. 547,450 referenced above, the extension detector was a linear array of 32 discrete detectors of CdW0 4 scintillating crystals mounted atop and optically coupled to a UV enhanced silicon photodiode. Our new array of this invention consists of 7×32 discrete detectors. Our array photodiode has an active area of 6 mm 2 and the crystal has an active face of 24 mm 2 . The slice thickness is on the other of 1 cm.
The plural fan beams 67-1 through 67-7 fall on the IIT as explained more fully in the referenced application Ser. No. 547,450. The fan beam in the referenced applications is converted to visible light in the (IIT) and transmitted through lens 68 and right angle mirror 69 to lens 73 and then to a one dimensional photodiode array. In this invention, the photodiode array 44 can be a stack of a plurality of linear arrays 44-1 through 44-7, or it could be a single two dimensional charged coupled detector (CCD). To obtain a spatial resolution of 1 mm on an object, it is necessary to achieve at least 0.9 line pairs/mm. Commercially available CCD arrays with this resolution, such as Texas Instruments TC 215 (1024×1024) or Tektronic (512×512), are available.
A multichannel scanning charge preamplifier, as described in copending Ser. No. 547,450 is used to introduce data from each of the fan beam from the extension detector 45 and multiplex this data with the ITT data from the 2D detectors 44-1 through 44-7.
Preferably, the projection from all the fans are accumulated in computer 80 and simultaneously processed to construct the density function plots for each slice. Algorithms to perform the reconstruction for each fan beam are disclosed in the referenced Parent Application Ser. No. 07/547,596.
To produce images within the same general time as in the prior art, since 7 times the amount of data is being taken, simultaneously, computation speed increases on the order of 7 would be needed. The commercially available array processors such as Intel i 860 have speeds of 4 times that of previous chips, on the order of 80 mega floating point operations per second. By combining N such cards it is possible to increase computational speed by a factor of 4N over the single scan system of copending Reference Application Ser. No. 07/547,596. Alternatively, the data for treatment planning does not necessarily need to be available in real time and the simultaneous collected images can be reconstructed off-line without using the program and the same speed computer as in the system described in Cross Reference Application Ser. No. 07/547,596, filed Jul. 2, 1990.
To enable the operator to view images in real time, or to retain the alternative of operating the system in the single fan beam mode without changing the X-ray tube, a power supply 83, FIG. 2, is provided with the capability to switch off the excitation of the X-ray tube filaments except for the single central filament, 61-4. To retain the same number of pins in the base of the modified X-ray tube, as in a normal two filament X-ray tube, all the filaments of our X-ray Tube are in series and the central filament is tapped on both sides so that it can be excited exclusively. Since the scanning rate for the Simulator is slower than a standard diagnostic X-ray tube, it is only necessary to provide 15 ma current for each filament at 125 KV to obtain the required X-ray dosage. Current X-ray tubes can provide this power level.
With reference to FIG. 3A, the X-ray tube motor 101 rotates the tungsten target 61 at high speed, i.e., near 10,000 RPM and the X-ray fan 102 is shown in relation to the isocenter 2 and the normal position for scanning a patient's head 103. FIG. 3B discloses the relationship of the spots 61-1 through 61-7 on the rotating anode target bevel as seen from the front. The lead collimator 88, shown more fully in FIGS. 4 and 4A, is seen to define the width of each of the fans 67-1 through 67-7 which impinge on the patent. The collimator 89 defines the width of the fan beams as they leave the post collimator 89 and enter the detector. FIG. 4, 4A and 4B define the details of the geometry of the relationship between the X-ray target 61 and the collimators 88 and 89. In particular, the central spot 61-4, is 100.0 cm from the isocenter and 55.0 cm from collimator 88. The collimator gaps are on 1.50 cm centers, and each gap is 7 mm. The collimator 89 is also on 1.50 cm centers where the collimator wall portion is 0.2 cm wide.
The post collimator 89 gaps and dimensions and the precollimator 88 gaps and dimensions need to be configurated so that no source spot on the rotating anode has a direct line of sight to any portion of the detector except the portion of the detector which lies on the ray containing the source spot, the center of the corresponding pre collimator gap and the center of the corresponding post collimator gap. Between the collimator 89 and the IIT 65 is an antiscatter focus grid 38 which further rejects X-rays other than line-of-sight X-rays including X-ray scatter from the patient.
Further with respect to FIG. 4, below the collimator 89 is schematically illustrated a series of detector arrays 44' and 45'. As described earlier, the number of detector arrays 44 equaled the number of fan beams. In FIG. 4, we disclose the alternative of employing twice the number of detectors plus 1 times the number of fan beams.
In the copending referenced parent application, Ser. No. 547,799, we describe a crosstalk error as a two dimensional point spread function. This error is seen to arise when a portion of the amplitude received at a detector did not follow the pencil beam path from the source to the detector. This comes from short range scatter and long range scatter (or crosstalk) from X-rays that are along other paths. Although in our earlier patent we provided a correction for the spread function, it was based on theoretical assumption of the model which are not always highly accurate. In this invention, by providing 2N+1 detectors and placing the detectors such that alternative detectors are shielded from the direct X-ray beam by the post collimators 89 we can improve the point spread function correction. Thus, the amplitude received by detectors in the valleys located between the high photon intensity directly receiving detectors corresponds to the crosstalk only. Accordingly, this crosstalk data can be smoothed, interpolated, averaged involving appropriate numerical manipulations to provide a correction for the detector readings from the ridges by subtracting out a position interpolated reading based on the nearby valley position detectors. This provides a much improved point spread correction since it is based on nearby measurement under identical conditions at identical times.
This invention is not intended to be restricted to the particulars of the embodiment disclosed, and it is understood that it can be accomplished by alternate equivalent means. The scope of the invention should be construed by the following claims. | A slow scanning CT Scanner providing slice data simultaneously for a plurality of slices so as to avoid blurring between adjacent slices due to patient movement. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to the field of electrical assist of traditionally human powered vehicles, e.g., bicycles, scooters, etc. More particularly, the present invention relates to bicycles equipped with a braking system that utilizes brake rotors and calipers. Specifically, the present invention relates to retrofitting electric assist to pedal-powered bicycles that use brake rotors and calipers.
2. Discussion of the Related Art
Riding bicycles is a popular pastime for physical exercise as well as a means of transportation. In an effort to promote the utilitarian benefits of bicycle riding, electric bicycles have become popular in recent times. Electric bicycles allow individuals to use the same bicycle to get physical exercise as well as a means of transportation while avoiding exhaustion. This may be done by allowing the operator to pedal as the sole means of propulsion, use an electric drive as the sole means of propulsion, or use the electric drive to assist the pedaling efforts of the operator. Electric bicycles supplement the riders pedaling motion to minimize fatigue, increase the distance the operator can travel, and provide a more relaxing means of transportation.
One drawback to electric bicycles is that they are considerably expensive. When the bicycle is designed from the ground up to incorporate electronic controls, an electric, motor, a battery pack, and the necessary hardware, it imposes a significant financial burden that many consumers are not willing to absorb. As a result, retrofitting existing bicycles with electric drives has become popular.
When retrofitting a bicycle with an electric drive, there are a number of possible locations to mount the electric equipment on the bicycle. One problem is that there is limited space available on a bicycle frame to accommodate the electric drive equipment. It is therefore desirable to minimize the components needed as well as minimize the required space needed for the electric drive. It is also desirable to improve existing electric bicycle retrofit packages by utilizing existing components of the pedal drive.
Another drawback to existing electric drive retrofits is that they utilize their own components to transfer the assisted power from the electric motor to the bicycle. For example, one popular retrofit uses a completely new rear wheel with an electric motor incorporated into the central hub of the wheel. This solution is typically very expensive and wheel damage is harder to repair as it is not a common “off the shelf” item. Other common electric retrofits add an electric motor to the bicycle frame and transfer power with a series of belts and/or chains. The added gear may be added directly to the crank or to the gears on the rear wheel. An added chain or belt is then used, providing additional weight, complexity, and maintenance to the bicycle.
What is therefore needed is an electric bicycle retrofit that utilizes existing components of the bicycle. What is also needed is a way to transfer the electric assist power to the bicycle without additional chains or gears. What is also needed is an improved electric retrofit that utilizes less space on the bicycle frame.
SUMMARY AND OBJECTS OF THE INVENTION
A pedal-powered bicycle frame may be retrofitted with an electric assist that attaches to the frame of the bicycle. More specifically, the electric assist may attach to the brake system of the bicycle. The brake system may include a device for attaching the brake system to the frame, a brake rotor with rotor gear teeth rotatably attached to the flame, and a brake caliper configured to selectively engage the rotor. In order to provide rotational force to the wheels of the bicycle, an electric motor may be attached to the device and also configured to engage the brake rotor gear teeth thus providing rotational force to the brake rotor and propelling the bicycle.
The electric retrofit assembly, including the electric motor and brake rotor, may be configured to retrofit onto the bicycle frame without modification of the brake caliper, frame, or the wheels attached to the frame.
In one embodiment, the brake rotor gear teeth may extend from the outer circumference of the brake rotor and selectively engage and disengage with a motor gear attached to the electric motor. In another embodiment, the brake rotor gear teeth may be between the outer circumference and a center point of the brake rotor. In this embodiment, each gear tooth consists of a hole in the side of the brake rotor. A plurality of holes, or gear teeth, may form multiple circumferential rings in the face of the brake rotor, each circumferential ring having a distinct diameter which produces a distinct gear ratio for each circumferential ring.
In the embodiment where the brake rotor includes circumferential rings, a shifting device may be configured to selectively engage and disengage the motor gear with each one of the circumferential rings while the bicycle is in motion and the brake rotor is turning. The motor gear may include an angle gear configured to engage the plurality of circumferential rings at a 90-degree angle to a face of the brake rotor.
In any embodiment, the electric motor may also provide braking by utilizing electrical regenerative braking, wherein the motor converts kinetic energy into electrical energy. Also in any embodiment, the electric motor may attach to the attachment device of the brake caliper, or may attach to the rear dropout, or axle, portion of the rear wheel of the bicycle. Regardless of the attachment point, the bicycle frame, wheels, and brake caliper do not require modification.
These and other aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
A clear conception of the advantages and features constituting the present invention, and of the construction and operation of typical mechanisms provided with the present invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings accompanying and forming a part of this specification, wherein like reference numerals designate the same elements in the several views, and in which:
FIG. 1 illustrates a side view of an electric motor and brake rotor drive gear attached to a bicycle frame according to one embodiment of the invention;
FIG. 1A illustrates a side view of an electric motor and brake rotor drive gear attached to the front fork of a bicycle frame according to another embodiment of the invention;
FIG. 2 illustrates a side view of an electric motor and brake rotor drive gear attached to a frame of a bicycle according to another embodiment of the invention; and
FIG. 3 illustrates a side view of an electric motor and brake rotor drive gear attached to a frame of a bicycle according to yet another embodiment of the invention;
In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the words “connected”, “attached”, or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.
DETAILED DESCRIPTION OF EMBODIMENTS
The present invention and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments described in detail in the following description. While the invention is directed toward use with bicycles, it is not limited to just traditional bicycles. The term “bicycle” is used to include any multi-wheeled form of transportation which may or may not include a seat. For example, scooters that support a rider in an upright, standing position are also included in the term “bicycle”. The “bicycle” may be chain driven, belt driven, pulley driven, gear driven, or any other form of rotational motion delivery.
An electric drive 8 retrofit is shown in FIG. 1 attached to a frame 10 of a bicycle. Bicycle frames 10 commonly include a seat stay tube 12 and a chain stay tube 14 that converge at a rear wheel dropout 16 . The electric drive may also attach to any other bicycle regardless of the frame design. While it is preferred that the electric drive 8 be utilized on a frame 10 equipped with disc brakes, the electric drive 8 may be used on any wheeled vehicle. The electric drive 8 may also be used as a braking device through regenerative braking, where the kinetic energy of the rotating rotor 22 is converted into potential energy, or electricity, for storage in a battery pack on board the frame 10 .
The electric drive 8 consists of an electric motor 26 that powers a motor gear 32 . The motor gear 32 includes a plurality of motor gear teeth 34 that extend from the outer diameter of the motor gear 32 forming a spur gear. While a spur gear is shown, any other type of gear may be used such as internal ring gears, helical gears, face gears, worm gears, or the like.
In order to provide the frame 10 with forward momentum, the gear teeth 34 mesh with a mating gear incorporated in the brake rotor 22 . The brake rotor 22 may include rotor vents 38 which serve to cool the rotor 22 as well as lighten it. The brake rotor 22 may also be solid without vents 38 . Preferably, the rotor 22 mounts to the frame 10 about the rear wheel dropout 16 without any kind of modification to the rear wheel dropout 16 , the center axle 40 , the caliper 20 , bicycle drive chain 36 , or any other component of the bicycle. The electric drive 8 may also be attached to the frame 10 on the front fork 11 or front wheel portion of the bicycle in any of the mentioned embodiments. For example, FIG. 1A shows the electric drive 8 attached to the front fork 11 using a motor bracket 52 , similar to FIG. 1 . Any of the embodiments shown in FIGS. 2 and 3 may also be similarly located on the front fork 11 . All other components of the electric drive 8 remain the same, but locating the electric drive 8 on the front fork 11 improves bicycle performance when a suspension 13 is used. In bicycles with a suspension 13 , such as a shock absorber and/or spring, in the front portion, the un-sprung weight of the bicycle is reduced. Contrary to the rear wheel portion of the bicycle, the rear wheel dropout 16 is not commonly sprung when a suspension is used. However, the front fork 11 portion where the brake rotor 22 is located is often sprung with a suspension 13 . By locating the electric drive 8 on the front fork 11 , the un-sprung weight is reduced and the performance of the suspension 13 is increased.
By utilizing the rotor 22 as the drive gear for the electric drive 8 , the typical necessity of adding an additional gear, chain, belt, pulley, or any other device for an electrical, assist retrofit is eliminated. Also, the bicycle chain drive 36 and related gears are not tampered with.
In previous electric bicycle retrofits installation required a bicycle expert to disassemble the rear wheel and chain drive 36 from the frame 10 . By using the brake rotor 22 as the drive gear for the electric motor 26 , installation is simplified. The caliper 20 and brake line 18 may also remain in their original location. As a result, the electric drive 8 reduces the weight, cost, complexity, and installation difficulty of known electric drives.
For bicycles originally equipped with brake rotors, the rotor 22 may be furnished as a direct retrofit and not require any adjustment to the caliper 20 . For bicycles that do not have brake rotors, a conventional “disc brake” retrofit kit may be used that implements the rotor 22 with rotor gear teeth 28 . Additionally, the motor 26 may include a mounting attachment such as the motor mount eyes 30 or any other suitable fastening means. The motor 26 may either attach directly to the frame 10 by affixing to the caliper mount eyes 24 or with a motor bracket 52 to give the motor 26 the proper offset and clearance, thus allowing the motor gear 32 to mesh with the rotor 22 . On bicycles that use threaded bosses for caliper attachment, a similar motor bracket 52 may be used or the motor 26 may be designed with a housing allowing attachment without a motor bracket 52 .
While FIG. 1 shows the caliper 20 attached to the seat stay tube 12 of the frame 10 , the caliper 20 may also attach to the chain stay tube 14 with or without a motor bracket 52 . According to FIG. 2 , the electric motor 26 may also attached to the rear wheel dropout 16 with a fastener attached to the center axle 40 or other existing fastener.
When mounting the motor 26 to the rear wheel dropout 16 , a different type of gear on the motor 26 may be used. As shown in FIG. 2 , the same rotor 22 may be used with rotor teeth 28 on the outer circumference of the rotor 22 . The motor 26 may include an angle gear 44 that meshes with the rotor gear teeth 28 at approximately a 90-degree angle. The angle gear 44 may extend from the motor 26 with a shaft 42 to provide optimal clearance or may be directly attached to the motor 26 without an extended shaft 42 . In this embodiment, the caliper 20 and caliper mount eyes are not used to retain the motor 26 . As a result, the motor bracket 52 shown in FIG. 1 may be eliminated.
Transitioning now to FIG. 3 , an alternative embodiment is shown wherein an alternative rotor 23 is used that does not include teeth on the outer circumference of the rotor 23 . The rotor 23 instead has a series of gear teeth circumferences 47 formed with concentric rings of holes 46 formed in the face of the rotor 23 . Each gear teeth circumference 47 forms an independent gear in the rotor 23 . The holes 46 allow for teeth on the angle gear 44 to insert into the holes 46 . As the motor 26 rotates the angle gear 44 , the rotor may be rotated thus providing forward momentum to the frame 10 of the bicycle.
The plurality of gear teeth circumferences forms a first gear teeth circumference 48 , a second gear teeth circumference 50 , and a third gear circumference 54 . Each gear circumference has a unique circumference, which means each gear teeth circumference 47 also has a different amount of holes 46 . As a result, the larger the gear teeth circumference, the taller the gear ratio. Similarly, the smaller the gear teeth circumference, the shorter the ratio.
The motor 26 may include a movable angle gear 44 which may move along the face of the rotor 23 along the shaft 42 or with any other suitable positioning device. In this configuration, multiple gear ratios may be attained allowing an operator to shift the angle gear 44 along a path and mesh with each gear teeth circumference 47 while the bicycle is in motion. As a result, the electric power stored onboard the frame 10 (not shown), may be conserved and utilized more efficiently by shifting the angle gear to a desired gear ratio for different inclines, terrains, or level of electrical assistance. The shifting may be used in combination with electronic controls (not shown) that can automate the shifting resulting in an automatic transmission, or the user may be able to selectively engage each gear teeth circumference 47 . Shifting may also be accomplished with mechanical means such as cables, linkages, or the like. The motor 26 may also mount to the rear wheel dropout 16 as shown in FIG. 2 and utilize the rotor 23 with holes 46 and a shifting mechanism.
While the motor gear 32 is shown as a traditional spur gear that transfers rotational force from the motor 26 to the brake rotor 22 , the motor gear 32 may also perform the function of the caliper 20 . In such an embodiment, the motor gear 32 would include a split perpendicular to the gear teeth 32 dividing the motor gear 32 in half. A small spacing may be included between each motor gear 32 half with the rotor gear teeth 22 and a portion of the rotor 22 between the motor gear 32 halves. As the motor gear 32 is turned by the motor 26 , a portion of the motor gear 32 may engage the rotor gear teeth 28 to drive the brake rotor 22 . For example, the central axis of the motor gear 32 may include motor gear teeth 34 . When the operator engages the brakes via brake line 18 or other engagement means, each half of the motor gear 32 may “pinch” or clamp onto the rotor 22 which brings the rotation of the rotor 22 to a stop.
In a slightly different embodiment, the motor gear 32 is not split in half as mentioned above but may have a frictional device on each side of the motor gear 32 which acts just like pistons in a caliper slow the rotor's rotation.
In yet another embodiment, the motor gear 32 may be eliminated and replaced with drive wheels that engage each face of the rotor 22 with a frictional material exerting a clamping force of the rotor 22 . Each wheel may be rotated by the motor 26 to deliver rotational force. As a result, the brake rotor gear teeth 28 and caliper 20 may be eliminated. In order to provide braking, the motor 26 may be switched to a generator and provide regenerative braking power. The rotational force of the rotor 22 may be converted into electrical energy by the motor 26 which may then be stored in a storage device such as a battery. Also, the wheel may simply “lock-up” or provide added friction to the face of the rotor 22 in order to slow the rotation of the rotor 22 .
Although the best mode contemplated by the inventors of carrying out the present invention is disclosed above, practice of the present invention is not limited thereto. It will be manifest that various additions, modifications, and rearrangements of the features of the present invention may be made without deviating from the spirit and scope of the underlying inventive concept. It is intended that the appended claims cover all such additions, modifications, and rearrangements. Expedient embodiments of the present invention are differentiated by the appended claims. | An apparatus and method for an electric bike retrofit for a disc brakes vehicle include an electric motor coupled with a rotor brake. The apparatus and method provide advantages in that the drive gear for the electric motor may be integrated with the brake rotor decreasing weight and minimizing necessary parts. The electric motor may mount to the existing brake caliper mounts and drive the brake rotor without the use of a chain, belt, or the like. Multiple gear ratios may be incorporated into the brake rotor allowing for shifting and increased efficiency of the electric drive system. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation application of U.S. application Ser. No. 13/064,987, filed Apr. 29, 2011, which was a continuation of U.S. application Ser. No. 12/801,952, filed Jul. 2, 2010, which was a continuation of U.S. application Ser. No. 12/659,980, filed Mar. 26, 2010, which issued as U.S. Pat. No. 7,797,970, which was a divisional of U.S. application Ser. No. 11/806,245, filed May 30, 2007, which issued as U.S. Pat. No. 7,743,633, which in turn claims the benefit of Korean Patent Application Nos. 2006-49501 and 2006-49482, both filed on Jun. 1, 2006, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference.
BACKGROUND
1. Field
The present invention relates generally to a washing machine having at least one balancer, and more particularly to a washing machine having at least one balancer that increases durability by reinforcing strength and that is installed on a rotating tub in a convenient way.
2. Description of the Related Art
In general, washing machines do the laundry by spinning a spin tub containing the laundry by driving the spin tub with a driving motor. In a washing process, the spin tub is spun forward and backward at a low speed. In a dehydrating process, the spin tub is spun in one direction at a high speed.
When the spin tub is spun at a high speed in the dehydrating process, if the laundry leans to one side without uniform distribution in the spin tub or if the laundry leans to one side by an abrupt acceleration of the spin tub in the early stage of the dehydrating process, the spin tub undergoes a misalignment between the center of gravity and the center of rotation, which thus causes noise and vibration. The repetition of this phenomenon causes parts, such as a spin tub and its rotating shaft, a driving motor, etc., to break or to undergo a reduced life span.
Particularly, a drum type washing machine has a structure in which the spin tub containing laundry is horizontally disposed, and when the spin tub is spun at a high speed when the laundry is collected on the bottom of the spin tub by gravity in the dehydrating process, the spin tub undergoes a misalignment between the center of gravity and the center of rotation, thus resulting in a high possibility of causing excess noise and vibration.
Thus, the drum type washing machine is typically provided with at least one balancer for maintaining a dynamic balance of the spin tub. A balancer may also be applied to an upright type washing machine in which the spin tub is vertically installed.
An example of a washing machine having ball balancers is disclosed in Korean Patent Publication No. 1999-0038279. The ball balancers of a conventional washing machine include racers installed on the top and the bottom of a spin tub in order to maintain a dynamic balance when the spin tub is spun at a high speed, and steel balls and viscous oil are disposed within the racers to freely move in the racers.
Thus, when the spin tub is spun without maintaining a dynamic balance due to an unbalanced eccentric structure of the spin tub itself and lopsided distribution of the laundry in the spin tub, the steel balls compensate for this imbalance, and thus the spin tub can maintain the dynamic balance.
However, the ball balancers of the conventional washing machine have a structure in which upper and lower plates formed of plastic by injection molding are fused to each other, and a plurality of steel balls are disposed between the fused plates to make a circular motion, so that the ball balancers are continuously supplied with centrifugal force that is generated when the steel balls make a circular motion, and thus are deformed at walls thereof, which reduces the life span of the balancer.
Further, the ball balancers of the conventional washing machine do not have a means for guiding the ball balancers to be installed on the spin tub in place, so that it takes time to assemble the balancers to the spin tub.
In addition, the ball balancers of the conventional washing machine have a structure in which a racer includes upper and lower plates fused to each other, so that fusion scraps generated during fusion fall down both inwardly and outwardly of the racer. The fusion scraps that fall down inwardly of the racer prevent motion of the balls in the racer, and simultaneously result in generating vibration and noise.
SUMMARY
Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a washing machine having at least one balancer that increases durability by reinforcing the strength of the balancer, which is installed on a rotating tub in a rapid and convenient way.
Another object of the present invention is to provide a washing machine having at least one balancer, in which fusion scraps generated by fusion of the balancer are prevented from falling down inward and outward of the balancer.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.
In order to accomplish these objects, according to an aspect of the present invention, there is provided a washing machine having a spin tub to hold laundry to be washed and at least one balancer. The balancer includes first and second housings, the first housing having at least one support for reinforcing a strength of the balancer. The first and second housings have an annular shape and are fused together to form a closed internal space.
Here, the first housing may have the cross section of an approximately “C” shape, and the support protrudes outwardly from at least one of opposite walls of the first housing.
Further, the spin tub may include at least one annular recess corresponding to the balancer such that the balancer is able to be coupled to the spin tub by being fitted within the recess.
Further, the support may protrude from the first housing and comes into contact with a wall of the recess, and guides the balancer to be maintained in the recess in place.
Also, the supports may be continuously formed along and perpendicular to the opposite walls of the first housing.
Further, the supports may be disposed parallel to the opposite walls of the first housing at regular intervals.
Meanwhile, the washing machine may be a drum type washing machine. A front member may be attached to a front end of the spin tub and a rear member may be attached to a rear end of the spin tub. The recesses may be provided at the front and rear members of the spin tub, and the balancers may be coupled to opposite ends of the spin tub at the recesses of the front and rear members.
The foregoing and/or other aspects of the present invention can be achieved by providing a washing machine having at least one balancer. The balancer includes a first housing and a second housing fused to the first housing, and the first and second housings are fused together to form at least one pocket between the first housing and the second housing, the pocket capable of collecting fusion scraps generated during fusion.
Here, the first housing may include protruding fusion ridges protruding from ends of the first housing, and the second housing may include fusion grooves receiving the fusion ridges of the first housing when the first housing and the second housing are fused together.
Further, the first housing may further include inner pocket ridges protruding from the first housing and spaced inwardly apart with respect to the fusion ridges of the first housing.
Further, the second housing may further include outer pocket flanges protruding from the second housing and being situated on outer sides of the fusion grooves when the first housing is fused together with the second housing so the outer pocket flanges are spaced apart from the fusion ridges of the first housing by a predetermined distance, causing an outer pocket to be formed between the fusion ridges and the outer pocket flanges.
Further, the second housing may include guide ridges protruding from the second housing and protruding toward the first housing to closely contact the inner pocket ridges of the first housing when the first and second housings are fused together.
Also, the balancer may further include a plurality of balls disposed within an internal space formed by fusing the first and second housings together, the balls performing a balancing function.
In addition, the washing machine may further include a spin tub disposed horizontally, and the balancers may be installed at front and rear ends of the spin tub.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which
FIG. 1 is a sectional view illustrating a schematic structure of a washing machine according to the present invention;
FIG. 2 is a perspective view illustrating balancers according to the present invention, in which the balancers are disassembled from a spin tub;
FIG. 3 is a perspective view illustrating a balancer according to a first embodiment of the present invention;
FIG. 4 is an enlarged view illustrating section A of FIG. 1 in order to show the sectional structure of a balancer according to a first embodiment of the present invention;
FIG. 5 is a perspective view illustrating a balancer according to a second embodiment of the present invention;
FIG. 6 is an enlarged view illustrating the sectional structure of a balancer according to the second embodiment of the present invention;
FIG. 7 is a perspective view illustrating a disassembled balancer according to a third embodiment of the present invention;
FIG. 8 is a perspective view illustrating an assembled balancer according to the third embodiment of the present invention;
FIG. 9 is a partially enlarged view of FIG. 7 ; and
FIG. 10 is a sectional view taken line A-A of FIG. 8 .
DETAILED DESCRIPTION OF THE EMBODIMENTS
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.
Hereinafter, exemplary embodiments of the present invention will be described with reference to the attached drawings.
FIG. 1 is a sectional view illustrating the schematic structure of a washing machine according to the present invention.
As illustrated in FIG. 1 , a washing machine according to the present invention includes a housing 1 forming an external structure of the washing machine, a water reservoir 2 installed in the housing 1 and containing washing water, a spin tub 10 disposed rotatably in the water reservoir 2 which allows laundry to be placed in and washed therein, and a door 4 hinged to an open front of the housing 1 .
The water reservoir 2 has a feed pipe 5 and a detergent feeder 6 both disposed above the water reservoir 2 in order to supply washing water and detergent to the water reservoir 2 , and a drain pipe 7 installed therebelow in order to drain the washing water contained in the water reservoir 2 to the outside of the housing 1 when the laundry is completely done.
The spin tub 10 has a rotating shaft 8 disposed at the rear thereof so as to extend through the rear of the water reservoir 2 , and a driving motor 9 , with which the rotating shaft 8 is coupled, installed on a rear outer side thereof. Therefore, when the driving motor 9 is driven, the rotating shaft 8 is rotated together with the spin tub 10 .
The spin tub 10 is provided with a plurality of dehydrating holes 10 a at a periphery thereof so as to allow the water contained in the water reservoir 2 to flow into the spin tub 10 together with the detergent to wash the laundry in a washing cycle, and to allow the water to be drained to the outside of the housing 1 through a drain pipe 7 in a dehydrating cycle.
The spin tub 10 has a plurality of lifters 10 b disposed longitudinally therein. Thereby, as the spin tub 10 rotates at a low speed in the washing cycle, the laundry submerged in the water is raised up from the bottom of the spin tub 10 and then is lowered to the bottom of the spin tub 10 , so that the laundry can be effectively washed.
Thus, in the washing cycle, the rotating shaft 8 alternately rotates forward and backward by of the driving of the driving motor 9 to spin the spin tub 10 at a low speed, so that the laundry is washed. In the dehydrating cycle, the rotating shaft 8 rotates in one direction to spin the spin tub 10 at a high speed, so that the laundry is dehydrated.
When spun at a high speed in the dehydrating process, the spin tub 10 itself may undergo misalignment between the center of gravity and the center of rotation, or the laundry may lean to one side without uniform distribution in the spin tub 10 . In this case, the spin tub 10 does not maintain a dynamic balance.
In order to prevent this dynamic imbalance to allow the spin tub 10 to be spun at a high speed with the center of gravity and the center of rotation thereof matched with each other, the spin tub 10 is provided with balancers 20 or 30 according to a first or a second embodiment of the present invention (wherein only the balancer 20 according to a first embodiment is shown in FIGS. 1-4 ) at front and rear ends thereof. The structure of the balancers 20 and 30 according to the first and second embodiments of the present invention will be described with reference to FIGS. 2 through 6 .
FIG. 2 is a perspective view illustrating balancers according to the present invention, in which the balancers are disassembled from a spin tub.
As illustrated in FIG. 2 , the spin tub 10 includes a cylindrical body 11 that has open front and rear parts and is provided with the dehydrating holes 10 a and lifters 10 b , a front member 12 that is coupled to the open front part of the body 11 and is provided with an opening 14 permitting the laundry to be placed within or removed from the body 11 , and a rear member 13 that is coupled to the open rear part of the body 11 and with the rotating shaft 8 (see FIG. 1 ) for spinning the spin tub 10 .
The front member 12 is provided, at an edge thereof, with an annular recess 15 that has the cross section of an approximately “C” shape and is open to the front of the front member 12 in order to hold any one of the balancers 20 . Similarly, the rear member 13 is provided, at an edge thereof, with an annular, recess 15 (not shown) that is open to the rear of the front member 12 in order to hold the other of the balancers 20 .
The front and rear members 12 and 13 are fitted into and coupled to the front or rear edges of the body 11 in a screwed fashion or in any other fashion that allows the front and rear members 12 and 13 to be maintained to the body 11 of the spin tub 10 .
The balancers 20 , which are installed in the recesses 15 of the front and rear members 12 and 13 , have an annular shape and are filled therein with a plurality of metal balls 21 performing a balancing function and a viscous fluid (not shown) capable of adjusting a speed of motion of the balls 21 .
Now, the structure of the balancers 20 and 30 according to the first and second embodiments of the present invention will be described with reference to FIGS. 3 through 6 .
FIG. 3 is a perspective view illustrating a balancer according to a first embodiment of the present invention, and FIG. 4 is an enlarged view illustrating part A of FIG. 1 in order to show the sectional structure of a balancer according to a first embodiment of the present invention.
As illustrated in FIGS. 3 and 4 , a balancer 20 according to a first embodiment of the present invention has an annular shape and includes first and second housings 22 and 23 that are fused to define a closed internal space 20 a.
The first housing 22 has first and second walls 22 a and 22 b facing each other, and a third wall 22 c connecting ends of the first and second walls 22 a and 22 b , and thus has a cross section of an approximately “C” shape. The second housing 23 has opposite edges that protrude toward the first housing 22 and that are coupled to corresponding opposite ends 22 d of the first housing 22 by heat fusion.
The opposite ends 22 d of the first housing 22 protrude outward from the first and second walls 22 a and 22 b of the first housing 22 , and the edges of the second housing 23 are sized to cover the ends 22 d of the first housing 22 .
Thus, when the balancer 20 is fitted into the recess 15 of the front member 12 of the spin tub 10 , the first and second walls 22 a and 22 b are spaced apart from a wall of the recess 15 because of the ends and edges of the first and second housings 22 and 23 which protrude outward from the first and second walls 22 a and 22 b . Further, because the first and second walls 22 a and 22 b are relatively thin, the first and second walls 22 a and 22 b are raised outward when centrifugal force is applied thereto by the plurality of balls 21 that move in the internal space 20 a of the balancer 20 in order to perform the balancing function.
In this manner, the plurality of balls 21 make a circular motion in the balancer 20 , so that the first and second walls 22 a and 22 b are deformed by the centrifugal force applied to the first and second walls 22 a and 22 b of the first housing 22 . In order to prevent this deformation, the second housing 22 is provided with supports 24 according to a first embodiment of the present invention.
The supports 24 protrude from and perpendicular to the first and second walls 22 a and 22 b of the first housing 22 which are opposite each other, and may be continued along an outer surface of the first housing 22 , thereby having an overall annular shape.
The supports 24 have a length such that they extend from the first housing 22 to contact the wall of the recess 15 . Hence, the first and second walls 22 a and 22 b are further increased in strength, and additionally function to guide the balancer 20 so as to be maintained in the recess 15 in place.
Here, when the plurality of balls 21 make a circular motion in the first housing 22 , the centrifugal force acts in the direction moving away from the center of rotation of the spin tub 10 . Hence, the centrifugal force acts on the first wall 22 a to a stronger level when viewed in FIG. 4 . Thus, the supports 24 may be formed only on the first wall 22 a.
In the balancer 20 according to the first embodiment of the present invention, when the first and second housings 22 and 23 are fused together and fitted into the recess 15 of the spin tub 10 , the supports 24 are maintained in place while positioned along the wall of the recess 15 . Finally, the balancer 20 is coupled and fixed to the front member 12 of the spin tub 10 by screws (not shown) or in any other fashion that allows the balancer 20 to be coupled to the front member 12 .
Although not illustrated in detail, the balancer 20 is similarly installed on the rear member 13 of the spin tub 10 .
The ends 22 d of the first housing 22 include fusion ridges 42 a that protrude toward the second housing 23 . The fusion ridges 42 a are inserted within fusion grooves 43 a of the second housing 23 .
FIGS. 5 and 6 correspond to FIGS. 3 and 4 , and illustrate a balancer 30 according to a second embodiment of the present invention.
The balancer 30 according to the second embodiment of the present invention has an annular shape and includes first and second housings 32 and 33 that are fused together forming an internal space 30 a therebetween in which a plurality of balls 31 are disposed. The balancer 30 according to the second embodiment of the present invention is similar to that of balancer 20 according to the first embodiment of the present invention, except the structure of supports 34 of balancer 30 is different from that of the structure of the supports 24 of balancer 20 .
As illustrated in FIGS. 5 and 6 , the supports 34 according to the second embodiment of the present invention protrude parallel to first and second walls 32 a and 32 b of a first housing 32 which are opposite each other, and the supports 34 are disposed at regular intervals along the first and second walls 32 a and 32 b . The first housing 32 further includes a third wall 32 c . Ends 22 d of the first housing 32 extend from an end of the first and second walls 32 a and 32 b.
Similar to the supports 24 according to the first embodiment, the supports 34 of the second embodiment have a length such that the supports 34 extend from the first housing 32 to contact the wall of the recess 15 . The surfaces of the supports 34 thereby abut portions of the front member 12 . Hence, the first and second walls 32 a and 32 b are further increased in strength, and additionally function to guide the balancer 30 so as to be maintained in the recess 15 in place.
Next, the construction of a balancer 40 according to a third embodiment of the present invention will be described with reference to FIGS. 7 through 10 .
FIGS. 7 and 8 are perspective views illustrating disassembled and assembled balancers according to the third embodiment of the present invention, FIG. 9 is a partially enlarged view of FIG. 7 , and FIG. 10 is a sectional view taken along line A-A of FIG. 8 .
As illustrated in FIGS. 7 and 8 , a balancer 40 includes a first housing 42 having an annular shape and a second housing 43 having an annular shape that is fused to the first housing 42 , thereby forming an annular housing corresponding to the recess 15 (see FIG. 2 ) of the spin tub 10 . The first and second housings 42 and 43 may be, for example, formed of synthetic resin, such as plastic by injection molding.
As illustrated in FIG. 9 , the first housing 42 has a cross section of an approximately “C” shape, includes fusion ridges 42 a protruding to the second housing 43 at opposite ends thereof which are coupled with the second housing 43 , and inner pocket ridges 42 b protruding to the second housing 43 spaced inwardly apart from the fusion ridges 42 a.
The second housing 43 , which is coupled to opposite ends of the first housing 42 in order to form a closed internal space 40 a for holding a plurality of balls 41 and a viscous fluid, includes fusion grooves 43 a recessed along edges thereof so as to correspond to the fusion ridges 42 a , outer pocket flanges 43 b and guide ridges 43 c . The outer pocket flanges protrude to the first housing 42 on outer sides of the fusion grooves 43 a so as to be spaced apart from the fusion ridges 42 a of the first housing 42 by a predetermined distance. The guide ridges 43 c protrude to the first housing 42 on inner sides of the fusion grooves 43 a and closely contact the inner pocket ridges 42 b of the first housing 42 .
The guide ridges 43 c of the second housing 43 move in contact with the inner pocket ridges 42 b of the first housing 42 when the second housing 43 is fitted into the first housing 42 , to thereby guide the fusion ridges 42 a of the first housing 42 to be fitted into the fusion grooves 43 a of the second housing 43 rapidly and precisely.
Thus, when the fusion ridges 42 a of the first housing 42 are fitted into the fusion grooves 43 a of the second housing 43 in order to fuse the first housing 42 with the second housing 43 , as shown in FIG. 10 , an inner pocket 40 b having a predetermined spacing is formed between the fusion ridges 42 a and inner pocket ridges 42 b , and an outer pocket 40 c having a predetermined spacing is formed between the fusion ridges 42 a and the outer pocket flanges 43 b.
In this state, when heat is generated between the fusion ridges 42 a of the first housing 42 and the fusion grooves 43 a of the second housing 43 , the fusion ridges 42 a and the fusion grooves 43 a are firmly fused with each other. At fusion, fusion scraps that are generated by heat and fall down inward of the first housing 42 are collected in the inner pocket 40 b , so that the scraps are not introduced into the internal space 40 a of the balancer 40 in which the balls 41 move. Fusion scraps falling down outward of the first housing 42 are collected in the outer pocket 40 c , and thus are prevented from falling down outward of the balancer 40 .
In the embodiments, the balancers 20 , 30 and 40 have been described to be installed on a drum type washing machine by way of example, but it is apparent that the balancers can be applied to an upright type washing machine having a structure in which a spin tub is vertically installed.
As described above in detail, the washing machine according to the embodiments of the present invention has a high-strength structure in which at least one balancer is provided with at least one support protruding outward from the wall thereof, so that, although the strong centrifugal force acts on the wall of the balancer due to a plurality of balls making a circular motion in the balancer, the wall of the balancer is not deformed. Thus, the plurality of balls can make a smooth circular motion without causing excess vibration and noise, and thus increasing the durability and life span of the balancer.
Further, the washing machine according to the embodiments of the present invention has a structure in which the balancer can be rapidly and exactly positioned in the recess of the spin tub by the supports, so that an assembly time of the balance can be reduced.
In addition, the washing machine according to the present invention has a structure in which fusion scraps generated when the balancer is fused are collected in a plurality of pockets, and thus are prevented from falling down inward and outward of the balancer, so that the internal space of the balancer, in which a plurality of balls are filled and move in a circular motion, has a smooth surface without the addition of fusion scraps. As a result, the balls are able to move more smoothly, and excess noise and vibration are minimized. The balancer may have a clear outer surface to provide a fine appearance without the fusion scraps, so that it can be exactly coupled to the spin tub without obstruction caused by the fusion scraps.
Although a few embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims and their equivalents. | A drum type washing machine including a housing, a spin tub, and a ball balancer coupled to the spin tub, the ball balancer including a first plastic member and a second plastic member joined to each other to form an annular-shaped race, the first plastic member including a first side wall, a second side wall and a connecting wall to form a three-sided annular-shaped structure having an open side, and the second plastic member adapted to cover the open side, the three-sided annular-shaped structure having a U-shaped cross-section with a first rounded inside corner formed between the first side wall and the connecting wall and a second rounded inside corner formed between the second side wall and the connecting wall. A radius of curvature of each of the first and second rounded inside corners is greater than a radius of curvature of opposite diagonal inside corners of the annular-shaped race. | 3 |
FIELD OF THE INVENTION
[0001] The present invention relates to a double winding type electrode assembly, and, more particularly, to a double winding type electrode assembly constructed in a structure in which a cathode and an anode are opposite to each other while a separator is disposed between the cathode and the anode, wherein the electrode assembly is manufactured by preparing a plurality of cell units, each cell unit having a cathode sheet and an anode sheet, of a predetermined size, wound, while a separator is disposed between the cathode sheet and the anode sheet, each cell unit being elliptical in section, and sequentially winding the cell units while arranging the cell units on a long separator sheet.
BACKGROUND OF THE INVENTION
[0002] As mobile devices have been increasingly developed, and the demand for such mobile devices has increased, the demand for batteries has also sharply increased as an energy source for the mobile devices. Accordingly, much research on batteries satisfying various needs has been carried out.
[0003] In terms of the shape of batteries, the demand for prismatic secondary batteries or pouch-shaped secondary batteries, which are thin enough to be applied to products, such as mobile phones, is very high. In terms of the material for batteries, the demand for lithium secondary batteries, such as lithium ion batteries and lithium ion polymer batteries, having high energy density, high discharge voltage, and high output stability, is very high.
[0004] Furthermore, secondary batteries may be classified based on the construction of an electrode assembly having a cathode/separator/anode structure. For example, the electrode assembly may be constructed in a jelly-roll (winding) type structure in which long-sheet type cathodes and anodes are wound while separators are disposed respectively between the cathodes and the anodes, a stacking type structure in which pluralities of cathodes and anodes having a predetermined size are successively stacked one on another while separators are disposed respectively between the cathodes and the anodes, or a stacking/folding type structure in which pluralities of cathodes and anodes having a predetermined size are successively stacked one on another, while separators are disposed respectively between the cathodes and the anodes, to constitute a bi-cell or a full-cell, and then the bi-cell or the full-cell is wound. The details of the stacking/folding type electrode assembly are disclosed in Korean Patent Application Publication No. 2001-0082058, No. 2001-0082059, and No. 2001-0082060, which have been filed in the name of the applicant of the present patent application.
[0005] However, the conventional electrode assemblies have several problems.
[0006] First, the jelly-roll type electrode assembly is manufactured by densely winding long-sheet type cathodes and anodes with the result that the jelly-roll type electrode assembly is circular or elliptical in section. Consequently, stress, generated by the expansion and contraction of the electrodes during the charge and discharge of the electrode assembly, accumulates in the electrode assembly, and, when the stress accumulation exceeds a specific limit, the electrode assembly may be deformed. The deformation of the electrode assembly results in the nonuniform gap between the electrodes. As a result, the performance of the battery is abruptly deteriorated, and the safety of the battery is not secured due to an internal short circuit of the battery. Furthermore, it is difficult to rapidly wind the long-sheet type cathodes and anodes while maintaining uniformly the gap between the cathodes and anodes, and therefore, the productivity is lowered.
[0007] Secondly, the stacking type electrode assembly is manufactured by sequentially stacking pluralities of unit cathodes and anodes. As a result, it is additionally necessary to provide a process for transferring electrode plates, which are used to manufacture the unit cathodes and anodes. Furthermore, a great deal of time and effort is required to perform the sequential stacking process, and therefore, the productivity is lowered.
[0008] Thirdly, the stacking/folding type electrode assembly considerably makes up for the defects of the jelly-roll type electrode assembly and the stacking type electrode assembly. However, a stacking process is necessary to manufacture the bi-cell or the full-cell. Consequently, the stacking/folding type electrode assembly is not a complete solution.
[0009] In conclusion, the jelly-roll type electrode assembly is preferred in the aspect of productivity, and the stacking type electrode assembly and the stacking/folding type electrode assembly are preferred in the aspect of operational performance and safety of the battery. Nevertheless, there is high necessity for a new electrode assembly that is capable of providing higher productivity and operational performance of a battery while making up for the defects of the conventional electrode assemblies.
[0010] Especially, a large-sized battery module, which is used for middle- or large-sized devices, such as electric vehicles or hybrid electric vehicles, which have lately attracted much attention, needs a large number of battery cells (unit cells). Furthermore, it is required that the large-sized battery module have a long service life characteristic. Consequently, a new electrode assembly that can solve all the above-mentioned problems is seriously needed.
SUMMARY OF THE INVENTION
[0011] Therefore, the present invention has been made to solve the above problems, and other technical problems that have yet to be resolved.
[0012] As a result of a variety of extensive and intensive studies and experiments to solve the problems as described above, the inventors of the present invention have developed an electrode assembly constructed in a structure in which winding type cell units, as unit bodies, are wound while the cell units are arranged on a long separator sheet, and found that the double winding type electrode assembly is manufactured with a high productivity equivalent to that of the conventional jelly-roll type electrode assembly, and, in addition, the double winding type electrode assembly exhibits a high operational efficiency and safety equivalent to the conventional stacking type or stacking/folding type electrode assembly even after the electrode assembly according to the present invention is used for a long period of time. The present invention has been completed based on these findings.
[0013] In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a double winding type electrode assembly constructed in a structure in which a cathode and an anode are opposite to each other while a separator is disposed between the cathode and the anode, wherein the electrode assembly is manufactured by preparing a plurality of cell units, each cell unit having a cathode sheet and an anode sheet, of a predetermined size, wound, while a separator is disposed between the cathode sheet and the anode sheet, each cell unit being elliptical in section, and sequentially winding the cell units while arranging the cell units on a long separator sheet.
[0014] The electrode assembly according to the present invention is basically based on the winding structure, and therefore, it is possible to manufacture the electrode assembly according to the present invention with a higher productivity than the stacking structure. On the other hand, each cell unit is constructed in a structure in which the cathode and the anode are wound by the reduced number of winding times, with the result that stress, generated by the expansion and contraction of the electrodes during the continuous charge and discharge of the electrode assembly, does not accumulate in the electrode assembly, and therefore, the electrode assembly according to the present invention is not deformed even after the electrode assembly is used for a long period of time. For the jelly-roll type electrode assembly, the number of winding times of the electrode sheets is very large, and therefore, a large frictional force is generated in the longitudinal direction of the electrode sheets during the winding process. Furthermore, the stress, generated in the longitudinal direction of the electrode sheets by the expansion and contraction of the electrodes, is not removed due to the frictional force but accumulates in the electrode assembly. However, each cell unit of the present invention is constructed in a structure in which the electrode sheets are wound by the reduced number of winding times. Consequently, only a small frictional force is generated in the longitudinal direction of the electrode sheets during the winding process, and therefore, the stress accumulation does not occur.
[0015] The cell units are small-sized winding type unit cells, which are elliptical in section. The cell units may be manufactured by winding the cell units in a circular shape in section and then compressing the wound cell units such that the cell units are formed in the elliptical shape, or winding the cell units in an elliptical shape from the beginning. Preferably, the separator, disposed between the cathode and the anode, extends longer than the outer winding end of each electrode, such that the occurrence of a short circuit due to the contact between the cathode and the anode is prevented during the winding process or the operation of the electrode assembly. The elliptical sectional structure is substantially similar to a thin stacked sheet structure.
[0016] The number of winding times of each cell unit is, preferably 1 to 5, more preferably 2 to 4, based on the number of bending times of the respective electrode sheets in the elliptical structure. When the number of winding times of each cell unit is too large, the stress accumulation may occur, during the charge and discharge of the electrode assembly, due to the increase of the frictional force in the longitudinal direction of the electrode sheets.
[0017] When the winding process is performed to manufacture of each cell unit, the inside winding end of the cathode and the inside winding end of the anode may be located at approximately the same winding start point, or the inside winding end of the cathode and the inside winding end of the anode may be opposite to each other at the winding start point. Here, the term “inside winding end” means the end, of each electrode sheet, located at the inside of the each cell unit when each electrode sheet is wound in the circular or elliptical shape. Whereas, the term “outside winding end” means the end, of each electrode sheet, located at the outside of the each cell unit when each electrode sheet is wound.
[0018] The cell units may be constructed in various structures depending upon the location of the outside winding ends of the electrode sheets constituting each cell unit. For example, each cell unit may be a cell unit constructed in a structure in which the upper end electrode and the lower end electrode have different polarities (hereinafter, referred to as an ‘A-type cell unit’) or a cell unit constructed in a structure in which the upper end electrode and the lower end electrode have the same polarity (hereinafter, referred to as an ‘B-type cell unit’).
[0019] The A-type cell unit may be constructed in a structure in which the outside winding end of the cathode and the outside winding end of the anode are located on the same plane or a structure in which the outside winding end of the cathode and the outside winding end of the anode are not located on the same plane. Preferably, opposite round sides of each cell unit are surrounded by the anode sheet. This is because the anodes occupy a relatively large area, when a plurality of cell units are stacked in a cathode/anode facing structure, and therefore, when the electrode assembly according to the present invention is used, for example, in a lithium secondary battery, the dendritic growth of lithium metal at the anode is maximally retrained during the charge and discharge of the lithium secondary battery.
[0020] The B-type cell unit may be constructed in a structure in which the anode forms the outer winding surface or a structure in which the cathode forms the outer winding surface. Preferably, however, the outside winding end of the anode extends longer than the outside winding end of the cathode such that the dendritic growth of lithium metal is retrained.
[0021] As described above, the cell units are located on the long separator sheet, and are then wound, such that the cathodes and the anodes face each other at the interfaces of the cell units, to manufacture a double winding type electrode assembly according to the present invention.
[0022] In a preferred embodiment, the first cell unit, with which the winding process is initiated, and the second cell unit, among the cell units arranged on the separator sheet, are spaced apart from each other by a length sufficient such that the lower end electrode of the first cell unit is brought into contact with the upper end electrode of the second cell unit after the outer surface of the first cell unit is completely covered by the separator sheet during the winding process. Specifically, the first cell unit and the second cell unit are located on the separator sheet while the first cell unit and the second cell unit are spaced apart, by a distance corresponding to the width of at least one cell unit, from each other, and then the process for winding the cell units is performed.
[0023] As a result, the cell units are wound in a structure in which the upper end electrode of the first cell unit and the upper end electrode of the third cell unit have opposite polarities, the lower end electrode of the second cell unit and the upper end electrode of the fourth cell unit have opposite polarities, and the lower end electrode of the third cell unit and the upper end electrode of the fifth cell unit have opposite polarities. Based on this winding structure, it is possible to arrange the cell units in various structures as described above.
[0024] Preferably, the electrode assembly is constructed in a structure in which the lower end electrode of the last cell unit on the separator sheet (n th cell unit) and the lower end electrode of the n−1 th cell unit adjacent to the n th cell unit are anodes. The lower end electrode of the last cell unit and the lower end electrode of the n−1 th cell unit form the outer surface of the electrode assembly, i.e., the upper and lower end surfaces of the electrode assembly. Consequently, it is possible to maximally restrain the dendritic growth as previously described.
[0025] In this connection, several exemplary arrangements of the cell units are possible as follows.
[0026] In a first exemplary arrangement, the first cell unit and the second cell unit are A-type cell units whose upper end electrodes are cathodes (hereinafter, referred to as ‘Ac-type cell units’), the third cell unit is an A-type cell unit whose upper end electrode is an anode (hereinafter, referred to as an ‘Aa-type cell unit’), the fourth cell unit and the following cell units are sequentially disposed in a structure in which the Ac-type cell units and the Aa-type cell units are alternately arranged, and the n th cell unit is a B-type cell unit whose outer surface is an anode (hereinafter, referred to as a ‘Ba-type cell unit’).
[0027] In a second exemplary arrangement, the first cell unit and the second cell unit are Aa-type cell units, the third cell unit is an Ac-type cell unit, the fourth cell unit and the following cell units are sequentially disposed in a structure in which the Aa-type cell units and the Ac-type cell units are alternately arranged, the n−1 th cell unit is a Ba-type cell unit, and the n th cell unit is an Ac-type cell unit.
[0028] In a third exemplary arrangement, the first cell unit is a Ba-type cell unit, the second cell unit and the third cell unit are B-type cell units whose outer surfaces are cathodes (hereinafter, referred to as ‘Bc-type cell units’), the fourth cell unit and the following cell units are sequentially disposed in a structure in which the Bc-type cell units and the Ba-type cell units are alternately arranged two by two, and the n−1 th cell unit and the n th cell unit are Ba-type cell units.
[0029] However, other arrangements are also possible, and they must be interpreted to be within the scope of the present invention.
[0030] The number of cell units, wound while being located on the separator sheet, may be decided depending upon various factors, such as the number of winding times of each cell unit and the desired capacity of each cell unit. Preferably, the number of cell units is 2 to 10.
[0031] The separator sheet is not particularly restricted so long as the separator sheet is insulative and is constructed in a porous structure to allow the movement of ions like the separator disposed between the cathode and the anode of each cell unit.
[0032] In a preferred embodiment, the cell units are bonded to the separator sheet before the commencement of the winding process, such that the process for winding the cell units is easily performed on the separator sheet. At this time, the bonding of the cell units to the separator sheet may be accomplished, for example, by applying a solution, having a polymer, such as PVDF, HFD, PMMA, PEO, or PMMA, which is easily laminated at a low glass temperature (TG) and electrochemically stable at a potential range of 0 to 5 V, dissolved in a predetermined solvent, to a separator and drying the solution applied to the separator, to manufacture a separator sheet coated with a binder, placing cell units on the separator sheet, and applying predetermined pressure and heat to the cell units and the separator sheet.
[0033] The binder-coated separator sheet may be used as the separator material of each cell unit. The binder-coated separator sheet serves to maintain the elliptical sectional shape of each cell unit, during the manufacture of the electrode assembly, due to the coupling force between the binder-coated separator sheet and the electrodes.
[0034] The electrode assembly manufactured as described above may be applied to an electrochemical cell to generate electricity through the electrochemical reaction between the cathode and the anode. Typically, the electrode assembly is applied to a secondary battery.
[0035] The secondary battery is constructed in a structure in which an electrode assembly, which can be charged and discharged, is mounted in a battery case, while the electrode assembly is impregnated with an ion-containing electrolyte. In a preferred embodiment, the secondary battery is a lithium secondary battery.
[0036] Recently, the lithium secondary battery has attracted much attention as a power source of large-sized devices as well as small-size mobile devices. When the lithium secondary battery is applied to such devices, it is preferable for the lithium secondary battery to be light in weight. Preferably, a solution for reducing the weight of the secondary battery is to mount the electrode assembly in a pouch-shaped case made of an aluminum laminate sheet.
[0037] Furthermore, when the secondary battery is used as a power source for middle- or large-sized devices, as described above, it is preferable that the deterioration of the operational performance of the secondary battery be maximally restrained even after the secondary battery is used for a long period of time, the service life characteristics of the secondary battery be excellent, and the secondary battery be mass-produced with low costs. In this connection, the secondary battery including the electrode assembly according to the present invention is preferably used in a middle- or large-sized battery module as a unit cell.
[0038] The middle- or large-sized battery module is manufactured by connecting a plurality of unit cells in series or in series/parallel with each other such that the middle- or large-sized battery module provides high output and large capacity. The structure of the middle- or large-sized battery module is well known in the art to which present invention pertains, and therefore, a related description thereof will not be given.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0040] FIGS. 1 to 4 are vertical sectional views illustrating exemplary A-type cell units that can be used in an electrode assembly according to an embodiment of the present invention;
[0041] FIGS. 5 to 8 are vertical sectional views illustrating exemplary B-type cell units that can be used in an electrode assembly according to an embodiment of the present invention;
[0042] FIGS. 9 to 12 are typical views illustrating various arrangements of cell units when manufacturing an electrode assembly according to the present invention;
[0043] FIGS. 13 and 14 are typical views illustrating the electrode facing relationships during the stacking process of the cell units through the winding operation of the cell units based on the arrangement of FIG. 10 and the arrangement of FIG. 12 , respectively; and
[0044] FIG. 15 is a vertical sectional view typically illustrating an electrode assembly according to an embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0045] Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted, however, that the scope of the present invention is not limited by the illustrated embodiments.
[0046] FIGS. 1 to 3 are vertical sectional views typically illustrating exemplary A-type cell units that can be used in an electrode assembly according to an embodiment of the present invention, and FIGS. 5 to 7 are vertical sectional views typically illustrating exemplary B-type cell units that can be used in an electrode assembly according to an embodiment of the present invention. For convenience of description, separators, which are disposed respectively between cathodes and anodes, are omitted from the accompanying drawings. In addition, although the cell units, which are elliptical in section, are constructed in a substantially thin stacked sheet structure, as previously described, the cell units are exaggeratingly shown in the accompanying drawings for easy understanding.
[0047] Referring to these drawings, cell units 100 , 100 a , 200 , 300 , 300 a , and 400 are constructed in a flat elliptical structure in section. The cell units 100 , 100 a , 200 , 300 , 300 a , and 400 have electrode sheets, which are wound three or four times based on the number of bending times of the respective electrode sheets. Consequently, a large frictional force is not generated in the longitudinal direction of the electrode sheets, as compared to the conventional jelly-roll type electrode assembly, and therefore, stress accumulation does not occur during the charge and discharge of the electrode assembly.
[0048] Referring to FIG. 1 , the cell unit 100 is constructed in a structure in which the inside winding end 122 of an anode 110 is opposite to the inside winding end of a cathode 120 at the winding start point.
[0049] As in the cell unit 100 a of FIG. 3 , on the other hand, the inside winding end 112 of the anode 110 and the inside winding end 122 of the cathode 120 may be located at approximately the same winding start point. At this time, the inside winding end 112 of the anode 110 extends longer than the inside winding end 122 of the cathode 120 so as to further restrain the dendritic growth of lithium metal, as previously described. Also, no active material is applied to the extension region.
[0050] Although the winding start points are located at the same position, however, as in the cell unit 100 b of FIG. 4 , the inside winding end 112 of the anode 110 may extend longer than the inside winding end 122 of the cathode 120 , while the anode 110 is partially overlapped at the winding start region.
[0051] The winding structure of the cell unit may be confirmed through the cell unit 300 a of FIG. 7 and the cell unit 300 b of FIG. 8 , both of which are modifications of the cell unit 300 of FIG. 5 . Specifically, the inside winding end 312 of an anode 310 and the inside winding end 322 of a cathode 320 are located at approximately the same winding start point, while the inside winding end 312 of the anode 310 extends longer than the inside winding end 322 of the cathode 320 . However, the cathode 320 may be partially overlapped at the winding start region, as shown in FIG. 7 , or the anode 310 may be partially overlapped at the winding start region, as shown in FIG. 8 .
[0052] On the other hand, the cell units 100 , 200 , 300 , and 400 may be constructed in various structures based on the location of the outside winding ends of the electrode sheets constituting the cell units 100 , 200 , 300 , and 400 .
[0053] First, the A-type cell unit 100 of FIG. 1 and the A-type cell unit 200 of FIG. 2 are constructed in a structure in which the upper end electrode and the lower end electrode have different polarities. Specifically, the A-type cell unit 100 is constructed in a structure in which the outside winding ends 114 and 124 of the anode 110 and the cathode 120 are located on the same plane, whereas the A-type cell unit 200 is constructed in a structure in which the outside winding ends 214 and 224 of the anode 210 and the cathode 220 are not located on the same plane. Opposite round sides a of the A-type cell unit 100 are surrounded by the anode sheet 110 , and therefore, it is possible to further restrain the dendritic growth of lithium metal.
[0054] On the other hand, the B-type cell unit 300 of FIG. 5 and the B-type cell unit 400 of FIG. 6 are constructed in a structure in which the upper end electrode and the lower end electrode have the same polarity. Specifically, the Ba-type cell unit 300 is constructed in a structure in which the anode 310 forms the outer winding surface, whereas the Bb-type cell unit 400 is constructed in a structure in which the cathode 420 forms the outer winding surface. In the B-type cell units 300 and 400 , the outside winding ends 314 and 414 of the anodes 310 and 410 extend longer than the outside winding ends 324 and 424 of the cathodes 320 and 420 .
[0055] Separators (not shown) of the cell units 100 , 200 , 300 , and 400 extend at least longer than the outside winding ends 314 and 414 of the anodes 310 and 410 so as to prevent the occurrence of a short circuit due to the contact between the cathodes and the anodes. Also, the separators, the cathodes, and the anodes are preferably bonded to each other using a specific binder so as to maintain the wound state of the respective cell units 100 , 200 , 300 , and 400 .
[0056] FIGS. 9 to 12 are typical views illustrating various arrangements of cell units when manufacturing an electrode assembly according to the present invention.
[0057] Referring first to FIG. 9 , cell units are arranged on a long separator sheet, and then the cell units are sequentially wound from the right-side cell unit, so as to manufacture an electrode assembly.
[0058] The first cell unit 501 and the second cell unit 502 are located on the separator sheet while the first cell unit 501 and the second cell unit 502 are spaced apart by at least a distance corresponding to the width of one cell unit from each other. Consequently, when the outer surface of the first cell unit 510 is completely covered by the separator sheet 910 according to the winding operation, the lower end electrode of the first cell unit 501 is brought into contact with the upper end electrode of the second cell unit 502 .
[0059] During the sequential stacking process through the winding operation, the application length of the separator sheet 910 increases. For this reason, the cell units 502 , 503 , 504 , and 505 are arranged such that the distance between the respective cell units 502 , 503 , 504 , and 505 is gradually increased in the winding direction.
[0060] Also, during the stacking process, the respective cell units are constructed such that the cathodes and the anodes face each other at the stacked interfaces. Specifically, the first cell unit 501 and the second cell unit 502 are Ac-type cell units whose upper end electrodes are cathodes, the third cell unit 503 is an Aa-type cell unit whose upper end electrode is an anode, the fourth cell unit 504 is an Ac-type cell unit, and the final fifth cell unit 505 is a B-type anode cell unit whose outer surface is an anode.
[0061] Referring to FIG. 10 illustrating another example, the first cell unit 601 and the second cell unit 602 are Aa-type cell units, the third cell unit 603 is an Ac-type cell unit, the fourth cell unit 604 is a B-type anode cell unit, and the final fifth cell unit 605 is an Ac-type cell unit.
[0062] Referring to FIG. 11 illustrating a further example, the first cell unit 701 is a Ba-type cell unit, the second cell unit 702 and the third cell unit 703 are Bc-type cell units, the fourth cell unit 704 is a Ba-type cell unit, and the final fifth cell unit 705 is a Ba-type cell unit.
[0063] The arrangement of FIG. 12 is the same as the arrangement of FIG. 11 ; however, the respective cell units 801 , 802 , 803 , 804 , and 805 are wound by a reduced number of winding times, specifically, the number of winding times which is one time less than that of FIG. 11 .
[0064] For clearer understanding about the above-described arrangement modes, the electrode facing relationships during the stacking process of the cell units through the winding operation of the cell units based on the arrangement of FIG. 10 and the arrangement of FIG. 12 are illustrated respectively in FIGS. 13 and 14 .
[0065] Referring first to FIG. 13 , the first cell unit 601 and the second cell unit 602 are wound while the first cell unit 601 and the second cell unit 602 are spaced apart by a distance corresponding to the width of one cell unit. As a result, the upper end electrode (anode) of the first cell unit 601 is brought into contact with the upper end electrode (cathode) of the third cell unit 603 . Also, the lower end electrode (cathode) of the first cell unit 601 is brought into contact with the upper end electrode (anode) of the second cell unit 602 . Consequently, when the first cell unit 601 is an Aa-type cell unit, the second cell unit 602 must be an Aa-type cell unit or a Ba-type cell unit, and the third cell unit 603 must be an Ac-type cell unit or a Bc-type cell unit.
[0066] On the other hand, the second cell unit and the following cell units 602 , 603 . . . are sequentially stacked without a distance corresponding to the width of one cell unit. As a result, the lower end electrode (cathode) of the second cell unit 602 is brought into contact with the upper end electrode (anode) of the fourth cell unit, and the lower end electrode (anode) of the third cell unit 603 is brought into contact with the upper end electrode (cathode) of the fifth cell unit. Consequently, it is necessary for the cell units to be alternately arranged two by two, and therefore, the second cell unit 602 must be an Aa-type cell unit, and the third cell unit 603 must be an Ac-type cell unit.
[0067] Meanwhile, the lower end electrode of the n th cell unit 600 n and the lower end electrode of the n−1 th cell unit 600 n −1 form the outer surface of the electrode assembly at the final position. Preferably, therefore, the lower end electrode of the n th cell unit 600 n and the lower end electrode of the n−1 th cell unit 600 n −1 are anodes.
[0068] Referring now to FIG. 14 , the upper end electrode (anode) of the first cell unit 801 is brought into contact with the upper end electrode (cathode) of the third cell unit 803 , and the lower end electrode (anode) of the first cell unit 801 is brought into contact with the upper end electrode (cathode) of the second cell unit 802 . Consequently, when the first cell unit 801 is a Ba-type cell unit, the second cell unit 802 and the third cell unit 803 must be an Ac-type cell unit or a Bc-type cell unit.
[0069] Also, in the same principle as the previous description, the lower end electrode of the second cell unit 802 is brought into contact with the upper end electrode of the fourth cell unit, and the lower end electrode of the third cell unit 903 is brought into contact with the upper end electrode of the fifth cell unit. Consequently, the electrodes at the interfaces therebetween must have different polarities, and therefore, the second cell unit 802 and the third cell unit 803 must be a Bc-type cell unit.
[0070] An exemplary electrode assembly manufactured by the process described above is typically illustrated in FIG. 15 .
[0071] Referring to FIG. 15 , various kinds of unit cells 901 , 902 , 903 . . . are sequentially wound, while the unit cells 901 , 902 , 903 . . . are arranged on a separator sheet 901 in a specific combination, to constitute an electrode assembly 900 . The separator sheet 901 has a length sufficient to cover the electrode assembly 900 once after the completion of the winding process.
[0072] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
INDUSTRIAL APPLICABILITY
[0073] As apparent from the above description, the electrode assembly according to the present invention is manufactured with a high productivity equivalent to that of the conventional jelly-roll type electrode assembly. Furthermore, the electrode assembly according to the present invention exhibits a high operational efficiency and safety equivalent to the conventional stacking type or stacking/folding type electrode assembly even after the electrode assembly according to the present invention is used for a long period of time. | Disclosed herein is a double winding type electrode assembly constructed in a structure in which a cathode and an anode are opposite to each other while a separator is disposed between the cathode and the anode, wherein the electrode assembly is manufactured by preparing a plurality of cell units, each cell unit having a cathode sheet and an anode sheet, of a predetermined size, wound, while a separator is disposed between the cathode sheet and the anode sheet, each cell unit being elliptical in section, and sequentially winding the cell units while arranging the cell units on a long separator sheet. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a machine for machining workpieces of wood, plastic, and the like, in particular, a molding machine, comprising a transport path for the workpieces, at least one driven spindle on which a tool is seated, and further at least one adjustable element. The invention also relates to a method for adjusting such a machine.
2. Description of the Related Art
In known woodworking machines, in particular, molding machines, the adjustment or retooling for the purpose of machining different workpieces is a time-consuming and complex process. Accordingly, pressing elements, which are correlated with the tools, or stops and tabletops must be adjusted in addition to the tools themselves. For this purpose, first the tool is placed onto the spindle. Subsequently, the pressing elements, the stops, or the tabletops can be adjusted relative to this tool. Because of this process, the adjustment of the machine is time-consuming. Moreover, it is not ensured that, based on the adjustment, the workpiece to be machined by the tool will fulfill the required machining precision. Accordingly, it is conventional to run at least one workpiece in a preliminary run through the machine to compare the resulting profile of the workpiece with a nominal profile, and, in the case of deviations, to readjust the corresponding elements of the machine. In particular, the precise adjustment of the pressing elements relative to the tool is complex and time-consuming. After the preliminary run of the workpiece, the pressing elements must often be readjusted in order to obtain the desired high machining precision of the workpiece. The pressing elements are to be moved as closely as possible toward the workpiece in order to guide the workpiece during machining as precisely and stably as possible.
SUMMARY OF THE INVENTION
It is an object of the present invention to design the machine and the method of the aforementioned kind such that the adjustment and/or retooling on the machine can be performed within the shortest amount of time with high precision.
In accordance with the present invention, this is achieved in regard to the machine in that the machine has at least one data storage in which data at least of the tool are stored, which data are used to determine the position to be adjusted of the adjustable element relative to the tool, and that the data can be retrieved for positioning the adjustable element.
In accordance with the present invention, this is achieved in regard to the method in that the characteristic data of the tool are measured and stored in a data storage and that the data are supplied to a control unit which, under consideration of these data, calculates and makes available for further processing the position for the adjustable element.
In the machine according to the invention, characteristic data of the tool are measured external to the machine and are stored in a data storage. Based on the tool data stored in the data storage the adjustable element, such as pressing elements, pressing guides or rules etc., can be precisely positioned without the tool being seated in the machine.
When adjusting the machine, the characteristic data of the tool are supplied to a control unit which, based on the tool data, calculates and makes available for further processing the required position of the corresponding adjustable element.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
FIG. 1 is a schematic illustration of a side view of a machine according to the invention;
FIG. 2 is a plan view onto the machine according to FIG. 1, through which a wide workpiece is guided;
FIG. 3 is a plan view of the machine according to the invention in an illustration corresponding to FIG. 2, through which a narrow workpiece is guided;
FIG. 4 shows on an enlarged scale an upper spindle on which a tool with a large diameter is seated;
FIG. 5 shows the upper spindle according to FIG. 4 on which a tool with a small diameter is seated;
FIG. 6 shows on an enlarged scale a left spindle on which a tool with a large diameter is seated;
FIG. 7 shows the left spindle according to FIG. 6, on which a tool with a small diameter is seated;
FIG. 8 shows an axial control for the upper spindle of the machine according to the invention;
FIG. 9 shows in a schematic illustration the circuit diagram of the axial control; and
FIG. 10 shows a tool which is to be fastened on the spindles of the machine according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The machine according to the invention is a molding machine with which workpieces are profiled when passing through the machine. The workpieces are used, for example, for manufacturing window frames or door frames. The machine has a machine bed 1 on which the workpieces 3 to be machine are transported by means of at least one feeding unit 4 on the upper side 2 of the machine bed 1 . The feeding unit 4 has a transport beam 5 which is positioned at a spacing above the machine bed 1 and which has feeding rollers 6 for transporting the workpieces 3 through the machine. The feeding rollers 6 are seated on horizontal shafts 7 which are supported on free ends of feeding pendulums 8 . The feeding pendulums 8 are supported on a pendulum holder 10 pivotable about a parallel axle 9 positioned between them. The pendulum holder 10 is fastened to the transport beam 5 . Pressure cylinders 11 engage the free ends of the feeding pendulums 8 and are supported on the transport beam 5 . They force the feeding rollers 6 onto the workpiece 3 to be transported. The transport beam 5 can be adjusted in the vertical direction.
In the area below the feeding roller pair 6 shown in the right half of FIG. 1, a horizontal planing or dressing spindle 12 is provided. It has a planing table 13 arranged upstream thereof which can be adjusted in the vertical direction in order to adjust the cutting removal or cutting depth on the workpiece 3 . The planing or dressing spindle 12 is rotatably supported in the machine bed 1 . The two feeding rollers 6 are arranged in the area above the planing or dressing spindle 12 such that the shafts 7 of the feeding roller 6 are positioned on opposite sides of the axis of rotation of the planing spindle 12 , when viewed in a plan view. In FIG. 1, for reasons of simplifying the drawing, the tool, with which the underside of the workpiece 3 is machined and which is seated on the planing spindle, is illustrated only schematically in the form of its cutting circle.
The feeding roller pair 6 shown to the right in FIG. 1 has arranged downstream thereof a vertical spindle 14 on which a tool, illustrated only schematically, is seated with which the right side of the workpiece 3 is machined when viewing the workpiece 3 in the transport direction.
In the transport direction of the workpieces 3 behind the right vertical spindle 14 a vertical spindle 15 is arranged on which a tool, schematically illustrated, is seated with which the left side of the workpiece 3 , when viewed in the transport direction, is machined. At the level of this left spindle 15 a feeding roller pair 6 , illustrated at the center of FIG. 1, is positioned.
In the feeding direction, at a spacing behind this central feeding roller pair 6 , the machine is provided with an upper horizontal spindle 16 . The tool seated thereon machines the upper side of the workpiece 3 .
In the feeding direction of the workpiece 3 , at a minimal spacing behind the upper spindle 16 , a lower spindle 17 is provided in the machine bed 1 which has arranged with minimal spacing downstream thereof a table roller 18 supported in the machine bed. A tool, only schematically illustrated, is seated on the lower spindle 17 and machines the underside of the workpiece 3 when passing through the machine.
The feeding roller 6 shown to the left in FIG. 1 is positioned with minimal spacing in the feeding direction of the workpieces 3 behind a suction hood 19 below which the spindle 16 is arranged. In the area of the suction hood 19 adjustable pressing elements 20 and 21 are provided which are arranged with minimal spacing before and behind the tool seated on the spindle 16 and rest against the upper side of the workpiece 3 when the workpiece 3 is fed through the machine. The corresponding adjusting device is known (German patent document 43 32 281 A1) so that it will be explained only briefly in the following. In FIG. 1, the corresponding adjusting devices 22 to 25 are illustrated schematically. By adjusting the pressing elements 20 , 21 in these directions 22 to 25 , an optimal adaptation of the position of the pressing elements relative to the tool seated on the spindle 16 is realized, i.e., the pressing elements are advanced as closely as possible toward the tool. FIG. 10 shows in an exemplary fashion a tool 26 to be fastened on the spindle 16 and provided with profiled blades 27 . The blade profile 28 defines a maximum radius R max as well as a minimal radius R min of the tool 26 . The maximum radius R max determines the maximum cutting circle radius, and the smallest radius R min determines the minimum cutting circle radius of the tool 26 . The pressing elements 20 , 21 (FIG. 1) are adjusted relative to the maximum radius R max and the minimum radius R min of the tool 26 seated on the spindle 16 . It is also possible to adjust the pressing elements 20 , 21 relative to the maximum radius R max and the fluting depth (groove depth) of the profile produced on the workpiece 3 by means of the profiled blade 27 . The fluting depth (groove depth) is defined by R max −R min In this case, the pressing elements 20 , 21 are adjusted by adjustment in the direction 23 and 24 relative to the maximum radius R max and by adjustment in the direction 22 and 25 relative to the fluting depth (R max −R min ).
The tool 26 which is illustrated as an example can be placed onto any suitable spindle of the machine.
The transport beam 5 of the feeding unit 4 can be adjusted also in the vertical direction 29 , in order to adjust the feeding rollers 6 relative to the thickness of the workpiece 3 to be transported. However, it is also possible to adjust the transport beam 5 relative to the minimal cutting circle radius R min of the tool 26 which is seated in this case on the upper spindle 16 and relative to the workpiece thickness together with the upper spindle 16 .
The unmachined workpieces 3 are guided into the machine (FIG. 2) along a stop rule or stop guide 30 against which the workpieces 3 rest with their right side. The stop rule or guide 30 is adjustable transversely to the feeding direction of the workpiece 3 for adjusting the cutting depth or cutting removal of the tool seated on the right spindle 14 . The required cutting removal depends on the curvature and the oversize of the workpiece 3 . The term oversize in this connection is to be understood as the ratio of the workpiece blank width to the finished workpiece width. In the area downstream of the right spindle 14 a stop guide or rule 30 ′ is provided. In the feeding direction directly behind the right spindle 14 a stop 31 is positioned which is adjustable in the adjusting direction 32 relative to the tool seated on the right spindle 14 . The adjusting direction 32 is positioned parallel to the feeding direction of the workpiece 3 . The stop 31 is adjusted relative to the radii R max and R min of the tool seated on the spindle 14 .
The right spindle 14 is located on a slide 35 which is adjustable in the direction of arrow 34 perpendicularly to the feeding direction of the workpiece 3 . By moving the slide 35 in the adjusting direction 34 , the right spindle 14 can be adjusted precisely relative to the workpiece 3 or the stop guide 30 ′ as a function of the tool seated on the spindle 14 .
A tabletop 33 is positioned on the slide 35 and is also adjustable in the direction of arrow 34 . The tabletop 33 can also be adjusted relative to the slide 35 as well as the tool seated on the spindle 14 as a function of its maximum cutting circle radius R max .
The right spindle 14 is positioned underneath a suction hood (not illustrated) with which the cuttings that are produced during machining of the workpiece 3 are removed. The left spindle 15 has also correlated therewith a suction hood 36 . Upstream and downstream of the left spindle 15 viewed in the feeding direction, pressing elements 37 and 38 are provided which rests against the left side of the workpiece 3 when viewed in the feeding direction and, like the pressing elements 20 , 21 of the upper spindle 16 (FIG. 1 ), can be adjusted relative to the tool seated on the spindle 15 . The left spindle 15 is also supported on a slide 39 which is adjustable in the direction of arrow 40 perpendicularly to the feeding direction of the workpiece 3 in order to adjust the tool seated on the spindle 15 relative to the workpiece 3 . A tabletop 39 ′ is provided on the slide 39 which, like the tabletop 33 , is also adjusted relative to the maximum radius R max of the respective tool.
In the feeding direction at a spacing behind the left spindle 37 , two pressing rules or guides 41 and 42 are provided which are adjustable perpendicularly to the advancing direction of the workpiece 3 in the direction of arrows 43 and 44 . Accordingly, the pressing guides 41 , 42 can be adjusted relative to the width of the workpiece 3 . The adjustment can also be realized relative to the minimal radius R min of the tool seated on the left spindle 15 . The pressing guides 41 , 42 can then be adjusted to the workpiece width together with the tool seated on the left spindle 15 .
The feeding rollers 6 seated on the shafts 7 are adjusted such that they, in a plan view according to FIG. 2, rest in the direction of their width on the workpiece 3 whose width is, for example, larger than the width of the feeding rollers 6 . When advancing the workpiece 3 in the machine, first its underside is dressed with the tool seated on the planing or dressing spindle 12 . The planing table 13 (FIG. 1) is adjusted relative to the desired cutting removal (cutting depth) relative to the tool seated on the planing spindle 12 . Upon moving farther, the right side, in the feeding direction, is machined with the tool seated on the right spindle 14 . The tool seated on the left spindle 15 machines the left side of the workpiece 3 when moving farther through the machine. The upper side of the workpiece 3 is subsequently machined by the tool seated on the upper spindle 16 . By means of the tool seated on the lower spindle 17 , the underside of the workpiece 3 is finally machined again.
FIG. 3 shows that also very narrow workpieces 3 , whose width is substantially smaller than the width of the feeding rollers 6 , can be processed in the machine. Because of the narrow width of the workpiece 3 , the left spindle 15 and the pressing rules 41 , 42 must be adjusted perpendicularly to the feeding direction in the direction toward the stop rule or guide 30 . The slide 39 which supports the left spindle 15 is moved accordingly. In order to prevent a collision with the oppositely positioned feeding rollers 6 , the rollers 6 are axially returned according to the workpiece width and the radius R max of the tool seated on the spindle 15 . In a plan view according to FIG. 3, the feeding rollers 6 are positioned only with a portion of their width above to the transport path of the workpiece 3 . The left spindle 15 with the suction hood 36 and the adjusting device for the pressing elements 37 , 38 are arranged in the feeding direction of the workpiece 3 such that in the disclosed adjustment they will not collide with the feeding rollers 6 at the level of the planing spindle 12 and the neighboring stop rule 42 . The central feeding rollers 6 are adjusted in the direction of arrow 45 perpendicularly to the feeding direction together with the shafts 7 and/or the feeding pendulums 8 and the pendulum axle 9 and/or the pendulum holder 10 .
As illustrated in FIGS. 2 and 3, the pressing elements 37 , 38 of the left spindle can be adjusted in the same way as the pressing elements 20 , 21 of the upper spindle 16 . In this way, a simple adjustment of the pressing elements 37 , 38 relative to the tool seated on the left spindle 15 is possible.
FIG. 4 shows on an enlarged scale the upper spindle 16 which is positioned in a suction chamber 46 of the suction hood 19 . The size of the suction chamber 46 is matched to the diameter of the tool seated on the spindle 16 . This is achieved in that the walls of the suction chamber 46 are formed at least partially of the carriers 47 to 49 of the pressing elements 20 , 21 . The inner wall 50 of the suction chamber 46 extends approximately coaxially to the cutting circle diameter. The inner wall 50 has only a minimal spacing from the cutting circle diameter so that the cuttings, which are produced by machining the workpieces 3 , can reach optimally a suction channel 51 of the suction hood 19 .
FIG. 5 shows the situation when the upper spindle 16 has a tool with a small cutting circle diameter seated thereon. According to this small cutting circle diameter, the pressing elements 20 , 21 have been correspondingly adjusted. The carrier 49 for the pressing element 21 is moved downwardly in the direction of arrow 25 . The suction hood 19 has been moved in the direction of arrow 24 and the carrier 47 in the direction of arrows 22 and 23 . In this way, the size of the suction chamber 46 has been automatically decreased with the adjustment of the pressing elements 20 , 21 and thus matched to the smaller tool on the spindle 16 . The boundary of the suction chamber 46 , which is formed by the inner walls of the carriers 47 to 49 , is thus adjusted correspondingly when an adjustment of the pressing elements 20 , 21 is carried so that an automatic volume adaptation of the suction chamber 46 is achieved. In this way, it is possible that the cuttings, produced by a tool having a smaller cutting circle diameter, can be optimally removed by suction into the suction channel 51 . FIG. 5 shows as an example the situation when the tool seated on the spindle 16 has no fluting depth, i.e., the blades of this tool have a constant outer cutting diameter across their length. FIG. 4, on the other hand, shows the situation when the tool seated on the spindle 16 is a profiled blade with a fluting depth.
FIG. 6 shows in a plan view the left spindle 15 on which a tool with a large cutting circle diameter is seated. The tool seated on the left spindle 15 has in the described embodiment no profiled blade but a blade with straight cutting edge so that this blade does not have a profile depth. The tool or the spindle 15 is positioned in a suction chamber 52 of the suction width 36 . The two pressing elements 37 , 38 upstream and downstream of the spindle 15 are adjusted in the same way as the pressing elements 20 , 21 of the upper spindle 16 . In accordance with the suction hood 19 , the suction chamber 52 is delimited by the carriers 53 to 55 of the pressing elements 37 , 38 . At the level of the suction channel 56 an adjusting element 57 is provided that is pivotable about an axis 58 extending parallel to the spindle axis. The adjusting element 57 has a curved slot 59 engaged by a guide element 60 which is provided on the suction hood 36 . The adjusting element 57 has an end face 61 facing the spindle 15 and forming a part of the inner wall 62 of the suction chamber 52 . As in the case of the suction hood 19 , the suction chamber 52 is delimited also by the end faces 63 and 64 of the pressing elements 37 , 38 facing the spindle 15 . The suction channel 56 as well as the suction channel 51 adjoin tangentially the suction chamber 52 . An inlet opening 65 extends between the end face 61 of the adjusting element 57 and the oppositely positioned inner wall portion 66 . Accordingly, the inner wall 62 of the suction chamber 52 is matched approximately to the cutting circle diameter of the tools seated on the spindle 15 . The inner wall 62 has only a minimal spacing from the cutting circle diameter. Accordingly, the cuttings which are produced during machining of the workpiece 3 are guided via the inlet opening 65 reliably into the suction channel 56 . The end face 61 of the adjusting element 57 is formed by a cuttings guide plate which ensures that the cuttings are guided reliably to the inlet opening 65 .
FIG. 7 shows the situation in which on the spindle 15 a tool with a small outer cutting circle diameter is positioned. This tool has also blades with straight cutting edges. The pressing elements 37 , 38 are matched to the new outer cutting circle diameter by corresponding adjustments. Moreover, the adjusting element 58 is pivoted counter-clockwise about the axis 58 . The end face 61 is then no longer approximately tangentially positioned relative to the outer cutting circle diameter, as was the case in the position according to FIG. 6, but approximately radially. Otherwise, the carriers 53 to 55 have been moved for adjusting the pressing elements 37 , 38 in the same way as has been explained in connection with the pressing elements 20 , 21 .
As a result of the adjustment of the adjusting element 57 it is ensured that the inlet opening 65 is positioned close to the circumference of the tool. By doing so, the cuttings which are produced by machining the workpiece 3 are reliably sucked into the suction channel 56 . The pressing elements 37 , 38 are positioned with their end faces 63 , 64 so as to be adjacent to the outer cutting diameter of the tool.
FIG. 8 shows the axial control with the aid of the example of the upper spindle 16 of the machine. The tool 26 with which the upper side of the workpiece can be machined is seated on the spindle 16 . The workpiece 26 or the spindle 16 is positioned at a spacing above a machine table 67 of the machine. It is provided on a machine frame 68 which is part of the machine bed 1 . For adjustment to different workpieces of different thickness, respectively, to different outer cutting circle diameters of the tool, the spindle 16 must be adjusted in the radial direction 69 relative to the machine table 67 . For this purpose, in the machine bed a positioning motor 70 is provided which drives by means of the gear box 71 , preferably a bevel gear pair, a vertically arranged spindle 72 . The spindle 72 is preferably a trapezoidally threaded spindle. On the spindle 72 , a spindle slide 73 carrying the spindle 16 is supported by means of a nut 74 , preferably having a trapezoidal thread. By rotating the spindle 72 , the spindle slide 73 is adjusted by means of the nut 74 in the vertical direction 69 in order to adjust the spindle 16 in the desired position.
In order to be able to reliably adjust and/or read the displacement travel of the spindle slide 73 and thus of the spindle 16 , a travel measuring system 75 is provided. It has a read head 76 fastened on the machine frame 68 and has correlated therewith a graduation 77 provided on the spindle slide 73 . The read head 76 is connected by electrical lines 78 to a computer, a monitor or the like. In order to define final positions for the spindle slide 73 limit switches (not illustrated) can be provided.
A control system 79 is positioned upstream of the positioning motor 70 (FIG. 9 ). The control system 79 receives from a control unit 80 nominal values 81 which can be compared in the control system 79 with actual values 83 provided by the measuring system 75 . Moreover, the control system 79 receives from the positioning motor 70 signals 82 which characterize the rotational speed of the positioning motor 70 . As soon as the spindle slide 73 and thus the spindle 16 have reached a certain position, which is determined by the measuring system 75 , the rotational speed of the motor 70 is reduced. This is illustrated in the rotational speed/travel diagram of FIG. 9 . It is shown here that the motor 70 first adjusts at a high rotational speed the spindle slide 73 up to a certain position. As soon as this position has been reached, the rotational speed of the motor 70 is lowered, wherein the spindle slide 73 and spindle 16 can be moved position-controlled via the measuring system 75 into the desired position. In the control system 79 the comparison of the nominal values 81 provided by the control unit 80 and of the actual values 82 and 83 provided by the motor 70 and the measuring system 75 is carried out. As a result of the described position-controlled movement of the spindle 16 , a high positioning precision is achieved. As soon as the spindle 16 has reached its desired position, the position control is switched off.
In conventional machines the adjustment or retooling with regard to other workpieces is time-consuming and complicated. In particular, at least one workpiece must be transported through the machine in a preliminary run in order to compare the produced profile with the nominal profile and to perform readjustments should deviations occur. In the described machine the tool data are measured external to the machine and are stored in a data storage of the control unit in the form of data values. The tool data are the radial dimensions as well the axial dimension of the tool. FIG. 10 shows the tool 26 whose profiled blades 27 have the blade profile 28 . As a result of this profile 28 , the tool 26 has a minimum radius R min as well as a maximum radius R max . The fluting depth (groove depth) of the profiled blade 27 is defined by R max −R min . Moreover, the axial dimension A of the tool 26 is measured. This tool dimension A is the spacing of a characteristic location of the blade profile 28 from a contact surface 84 of the tool 26 on the spindle 16 . The above-mentioned tool data are measured external to the machine directly on the tool and stored. Moreover, the data storage stores the workpiece data, such as thickness, width, and respective profiled dimensions. Based on these tool and workpiece data stored in the storage device it is possible to adjust the adjustable spindles of the machine in the axial and radial direction, the corresponding pressing elements 20 , 21 ; 37 , 38 , the pressing guides 41 , 42 , the tabletops 33 , 39 ′, the transport beam 5 , the feeding rollers 6 , the dressing or planing table 13 , and the stop rule 30 , without the tool having to be seated in the machine. When subsequently the tool required for machining is placed onto the corresponding spindle with the selected adjustment of the machine, it is possible to immediately perform the desired processing of the workpieces 3 . A preliminary or sample run is not required. The retooling time from one workpiece profile to another is accordingly very short; skilled personnel for machine retooling are not required.
Advantageously, the position adjustment is carried out fully automatically. However, for a simpler embodiment of the machine it is also possible to show the operator on a display of the control unit which adjustment of the machine must be performed. The operator can then manually adjust the corresponding adjustable parts of the machine according to the displayed nominal position values. Also, it is advantageously possible to perform the greatest part of the adjustments fully automatically and to perform an adjustment by hand only for a few elements which must be adjusted seldomly. Such an element is, for example, the stop 31 .
In the case of the upper spindle 16 and the left spindle 15 the fluting depth of the tool (R max −R min ) and the radial dimension (R max ) of the tool are required for adjusting the pressing elements 20 , 21 and 37 , 38 .
In order to adjust the left pressing rules 41 , 42 in the adjusting direction 43 , 44 (FIG. 2 ), the smallest outer cutting circle radius R min of the left tool is used as a basis for the adjustment. The pressing guides 41 , 42 are adjusted such that their contact surfaces 85 , 86 are positioned tangentially to the smallest cutting circle diameter R min of the tool.
When adjusting the machine to the workpiece 3 to be processed, first the pressing elements 20 , 21 ; 37 , 38 as well as the pressing guides 41 , 42 are adjusted to the required position in the manner described. Subsequently, the respective tool, together with the adjustable elements adjusted as described, is adjusted relative to the workpiece to be machined in the axial and radial direction. Alternatively, the feed rollers 6 and the pressing guides 41 , 42 can be directly adjusted relative to the workpiece 3 into their desired or required position. For these adjustments, an adjusting drive is used, respectively, as is illustrated with the aid of FIG. 8 for the upper spindle 16 .
All adjustments are carried out via a control unit and via the operating panel of the machine.
For adjusting the spindles it is possible to provide, for example, CNC axles whose control is however complex and expensive. It is also known to drive a spindle by means of a motor on whose shaft a shaft encoder for position measuring is positioned. The rotational movement of the spindle is transformed by means of a trapezoidal thread into a linear movement of the spindle. Such axles are constructively simple and inexpensive but do not allow a high positional precision because of the play as well as wear and manufacturing tolerances of these axles. Should a high positional precision not be required, for example, in the adjustment of planing or dressing tables 13 or of the stop 30 or transport beam 5 , such simple axles can be used in the described machine. For a high positional precision in the machine described here, the spindle 72 (FIG. 8) is directly driven or driven by means of a gearbox 71 by the motor 70 . The adjusting stroke of the spindle slide 73 is measured directly on the spindle slide 73 by means of the measuring system 75 . The adjusting travel is supplied as an actual signal 83 to the control system 79 (FIG. 9 ). The control system 79 compares the actual value with the nominal value 81 provided by the control unit 80 and controls accordingly the motor 70 so that the spindle slide 73 and thus the spindle can be moved exactly into the nominal position. In this connection, it is unimportant whether the transmission chain from the motor 70 to the spindle slide 73 has elements with play because the measuring system 75 directly measures the adjusting stroke of the spindle slide 73 . For measuring the adjusting stroke a linear graduation (rule) can be used which has the required high measuring precision for the required application, respectively. The measuring system 75 can be in the form of any suitable linear measuring system.
With the aid of FIGS. 8 and 9, the adjustment of the upper spindle 16 has been explained. The other elements of the machine to be adjusted with high precision are adjusted also in the same way, in particular, the spindles and the pressing elements.
A further important feature of the machine is that the feeding rollers 6 have a width which is matched to the maximum possible width dimension of the workpieces 3 to be machined in the machine. Depending on the width of the workpiece 3 guided through the machine, the shafts 7 supporting the feeding rollers 6 are adjusted axially such that the feeding rollers 6 rest with optimal width on the workpiece 3 . FIG. 2 shows the situation in which a very wide workpiece 3 is transported through the machine. The shafts 7 of the feeding rollers 6 are adjusted such that the feeding rollers 6 rest with their entire width on the workpiece 3 .
When narrow workpieces 3 are to be transported through the machine (FIG. 3 ), the feeding rollers 6 or their shafts 7 can be returned in the axial direction 45 so that the feeding rollers 6 rest only over a portion of their width on the workpiece 3 . In FIG. 3 this is illustrated for the feeding rollers 6 positioned opposite the left spindle 15 . Since the feeding rollers 6 must not be positioned highly precisely, a conventionally controlled axle suffices for their adjustment. The feeding rollers 6 are adjusted axially to such an extent that they will not collide with the neighboring tool on the left spindle 15 . The adjusting value depends in this connection on the greatest cutting circle radius R max of the tool 26 . Since for narrow workpieces the left spindle 15 is adjusted transversely to the feeding direction of the workpieces 3 , a corresponding axial movement of the oppositely positioned feeding rollers 6 is required. The feeding rollers 6 correlated with the planing spindle (dressing spindle) 12 must not be axially adjusted but can remain in their position.
As a result of the axial movement of at least some of the feeding rollers 6 , an exchange of feeding rollers is not required as would be the case in conventional machines: depending on the width of the workpieces to be machined, different feeding rollers of different widths are positioned on the shafts in conventional machines. Since machines as described have a large number of feeding rollers, the retooling requires a considerable amount of time. It is also known to adjust the feeding rollers axially by hand. However, the manual adjustment is time-consuming and entails the risk that upon positioning of the left spindle a collision with erroneously adjusted feeding rollers can occur. In the described machine, the corresponding feeding rollers can be quickly axially adjusted so that retooling of the machine is possible within a shortest amount of time with high precision. The corresponding feeding rollers 6 or their shafts 7 are adjusted by the control unit 80 when corresponding workpieces are to be machined. This ensures that no collision will occur between the feeding rollers 6 and the tool.
When axially adjusting the feeding rollers 6 , the largest cutting circle radius R max of the tool and the width of the workpiece 3 to be machined are to be taken into account.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles. | A machine for machining workpieces of wood and plastic has a transport path for transporting workpieces through the machine. One or more driven spindles having a tool for machining the workpieces transported through the machine are provided. An adjustable element that is adjustable relative to the tool is provided. At least one data storage is provided for storing data at least of the tool wherein the data are used to determine a position of the adjustable element relative to the tool and are retrievable. In the method for adjusting the machine, characteristic data of the tool are measured and stored in the data storage. The characteristic data are supplied to a control unit. In the control unit positioning data for the adjustable element are calculated based on the characteristic data and then made available for processing the workpieces. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] None.
FIELD OF THE INVENTION
[0002] The invention relates to a thermal shingle sealing apparatus for applying heat to the thermally activate factory applied sealant on the shingles after their installation in cool weather to facilitate bonding of the layers of shingles. More particularly, the invention relates to an apparatus that may comprise a commercially available heater, a heat directing enclosure and a wheeled chassis, allowing an operator to bond the shingles in cool weather providing more wind protection immediately rather than waiting for sun's heat to activate the sealant.
SUMMARY OF THE INVENTION
[0003] The invention relates to a device for heating the factory installed sealant on the shingles, thereby bonding the shingles together in cool weather upon installation, and providing immediate wind protection. More particularly, the invention relates to a device having a heater and a disperser and a wheeled chassis where the heater is positioned adjacent to the disperser and supported by a wheeled chassis, directing heat downward, allowing the operator to push the device along each course of asphalt shingles heating the sealant underneath thereby bonding the shingles together on the roof.
[0004] Asphalt roof shingles are the most popular type of roofing material used on residential roofs and have been used successfully in United States in cold climates for over ninety years. Current industry practice requires that the activation temperature of the factory applied sealant be balanced with avoiding premature activation during packaging and storage and activation during and after installation. The consequence of this balance is the activation temperature is a compromise which requires interface temperatures to reach 140-160° F. before bonding of the shingles occurs in an installation. However, the activation temperature requirements for installation present an issue in cool weather and cold climates because there may be insufficient solar heating to bond the shingles properly.
[0005] Asphalt shingles are installed in courses, with each upper course overlapping the course below it. To affix the shingles to the roof, the shingles are nailed to the roof and additionally, most asphalt shingles are manufactured with a thermally activated sealant which bonds the shingles together once installed on the roof and exposed to a few weeks of sufficient solar heating to activate the sealant. This sealant works in conjunction with the nails to hold the shingles in place. However, during the winter months, the sun is low on the horizon and the air temperature is too cool for the sun to produce any significant heat to activate the sealant on the shingles, thus preventing the sealant from working properly, and preventing the adhesion of the adjacent shingle courses. As a result, the shingles can easily be lifted up and ripped off the roof when the winds are sufficiently strong.
[0006] During cool weather, one method to ensure wind protection until sufficient solar heating occurs is the hard sealing of the asphalt shingles by adding warm roofing tar or cement to the bottom half, back side, of each shingle prior to nailing it in place. This method increases the labor and material costs and imposes new difficulties to the installation. These difficulties include keeping the tar or cement warm during installation, and applying it to every shingle during installation. Additionally, this method for securing the shingles is inefficient because more manpower is required to accomplish the same job in the same allotted time or using the current manpower will require more time to finish the same job both of which are unacceptable in the industry.
[0007] U.S. Pat. No. 4,559,267 to Freshwater, teaches a factory applied stick-down system for roofing membranes or shingles employing a sealant compound that exhibits high tackiness at ambient temperatures, which permits sealing to occur at significantly reduced temperatures, while still avoiding premature activation during packaging and storage. The activation temperature was reduced to between 90-130° F. using the new compound. However, this invention did not address significantly cooler temperatures while installing the shingles.
[0008] The present invention overcomes these shortcomings in the prior art by providing a simple apparatus for heating and activating the sealant on site during cool weather immediately after shingle installation. The present invention fulfills the industry's need for facilitating cool weather installation by providing a device that can be used to bond the shingles in cool weather giving the home owner immediate wind protection after installation
[0009] There have thus been outlined, rather broadly, 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 the subject matter of the claims appended hereto.
[0010] In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this 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 description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings. 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.
[0011] Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientist, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of the apparatus with a forced air propane heater as a heat source attached to the disperser enclosure and the chassis.
[0013] FIG. 2 is a side view of the left side of the apparatus with an exploded view of the wheel.
[0014] FIG. 3 is a rear view of the apparatus.
[0015] FIG. 4 is a top view of the apparatus illustrating the controls.
[0016] FIG. 5 is an underside view of the apparatus illustrating the cavity defined by the enclosure.
[0017] FIG. 6 is an underside view of the apparatus with radiant heaters replacing the forced air propane heater as a heat source.
[0018] FIG. 7 is a side view of the left side of a second embodiment the apparatus.
[0019] FIG. 8 is a underside view of the second embodiment of the apparatus.
DETAILED DESCRIPTION OF THE INVENTION
[0020] FIG. 1 is a perspective view of the invention, a thermal shingle sealing apparatus 100 highlighting three components: a forced air propane heater 102 , a heat disperser 104 , and a frame 106 . In this embodiment a forced air propane heater 102 sits atop the heat disperser 104 and connects to the top panel 116 by a heater connector 114 . The forced air propane heater 102 may have an inside a blower 502 , a burner, an ignition system to ignite the propane and finally, a controller 108 to regulate the heat and prevent excessive heat during normal operations reducing the possibility of damaging the roof shingles.
[0021] There are at least two methods encompassed within the claims for providing heat. First, the forced air heating method, where a burner heats the air using some type of fossil fuel or an electrical element heats the air and then the air is blown onto the desired shingle area to activate the sealant and bond the shingles. Second, the radiant heating method is another technique where the heating element using fossil fuel or electricity is positioned directly above the desired shingle area and in close proximity to the shingles to heat and bond the shingles.
[0022] Propane may be replaced with other types of fossil fuels such as kerosene, natural gas, and diesel, depending the availability to the operator in their local area. Additionally, a radiant heater can replace the current forced air propane heater 102 used in the present invention to provide the heat source. Finally, the fossil fuel heat source may be replaced by removing the burner and ignition system and replacing them with heating elements where electricity provides the source of heat for the thermal shingle sealing apparatus 100 .
[0023] FIG. 1 further depicts the controller 108 mounted to the side of the forced air propane heater 102 with a temperature control knob 200 depicted later in FIG. 2 , and two connections, a power input 110 and a fuel input 112 . The first connection, the power input 110 preferably provides common household 120 volt electrical power to the thermal shingle sealing apparatus 100 by an electric power cord 136 . This power is supplied to the blower 502 , which provides the forced air and to the controller 108 . The second connection on the controller 108 is a connection for a fuel input 112 where the fuel is supplied to the thermal shingle sealing apparatus 100 through a fuel hose 134 .
[0024] As primarily described, propane is the fuel source utilized and is supplied by a propane tank 132 . Once the propane tank 132 is connected to the fuel input 112 and the power cord 136 is connected to common household power, the apparatus is ready to be utilized. To improve operability and safety, the power supplied to the power input 110 may be replaced by a battery and a power inverter with sufficient power to operate the blower 502 during normal sealing operation. Additionally, solar panels may be used to replenish energy to the battery during normal operations.
[0025] The heat disperser 104 is also shown in FIG. 1 . The forced air propane heater 102 is attached to the top panel 116 of the heat disperser 104 by a heater connector 114 . The heat disperser 104 consists of a top panel 116 , a front angle panel 118 , a front lower panel 120 , left and right side panels 122 , rear angle panel 306 , and a rear lower panel 308 . The rear angle panel 306 and rear lower panel 308 are depicted later in FIG. 3 in more detail. The front angle panel 118 and the rear angle panel 306 assist in deflecting the heat downward toward shingles. The panels of the current invention are fabricated from aluminum but one skilled in the art may use other materials to create the panels. These panels are preferably welded together at the seams to provide structural rigidity and support for the forced air propane heater 102 and to prevent heat loss. Welding is but one method to connect the panels together. One skilled in the art may choose other methods that are just as effective in providing structural rigidity to the disperser and prevent heat loss. These panels come together to create an enclosure by which air from the forced air propane heater 102 is directed down on to the shingles and the heat from the forced air propane heater 102 is contained within the heat disperser 104 thereby raising the temperature in the local area over the shingles covered by the heat disperser 104 in order to activate the sealant to bond the shingles together and provide wind protection for a newly installed roof in cool temperatures.
[0026] The chassis, as depicted in FIG. 1 , preferably consists of a frame 106 , four wheels 126 , and a handle 130 . The chassis is positioned to support the heat disperser 104 and the forced air propane heater 102 . The frame 106 preferably fits the perimeter of the heat disperser 104 , and it must be sufficiently strong to support the weight of the heat disperser 104 and the forced air propane heater 102 . Additionally, the chassis may be designed with sufficient strength to support mounting a propane tank 132 on the chassis.
[0027] At each corner of the chassis 106 is mounted a wheel 126 to allow the thermal shingle sealing apparatus 100 to be moved by a handle 130 during normal operations. The wheels 126 are affixed to the frame 106 by axle chassis connectors 124 where an axle 202 protrudes from the axle chassis connectors 124 through the wheels 126 to provide mobility and maneuverability. The wheel 126 assembly is further described in FIG. 2 . A handle 130 is connected to the frame 106 by a handle collar 128 . The handle collar 128 preferably allows for easy removal of the handle 130 for placement onto the roof before beginning operations. The handle 130 mounting is further described in FIG. 3 . It may be desirable to provide a handle that can be adjusted to a height comfortable for the particular operator.
[0028] FIG. 2 illustrates the left side of the thermal shingle sealing apparatus 100 with an exploded view of the wheel 126 . In this view, several features are illustrated, a temperature control knob 200 , skirts 208 , and wheels 126 . As illustrated above, the controller 108 affixed to the forced air propane heater 102 includes a temperature control knob 200 attached to the side of the controller 108 . The temperature control knob 200 allows the operator to choose a desired setting, which determines the amount of heat generated by the forced air propane heater 102 . This temperature control knob 200 comes standard with a commercially available forced air propane heater. An alternative to controlling the forced air propane heater 102 by the controller 108 is affixing a system control and display unit 220 on the handle 130 where the operator can control the temperature of the forced air propane heater 102 during operations. The details of the system control and display unit 220 are further described in FIG. 4 .
[0029] In order to provide consistent heating over the total area underneath the heat disperser 104 , heat directors 218 inside the cavity 500 are used to divert a portion of the air flow away from the central point directly underneath the forced air propane heater 102 . There are preferably multiple heat directors 218 affixed to the two side panels 122 that distribute the heat more evenly throughout the heat disperser 104 thereby providing more uniform heating under the heat disperser 104 in order to more efficiently activate the sealant and bond the shingles together.
[0030] FIG. 2 depicts the present invention with two wheels 126 on the left side of the thermal shingle sealing apparatus 100 . On the right side further illustrated later in FIG. 4 , is a set of companion wheels 126 . Each wheel 126 is attached to the frame 106 by an axle chassis connector 124 . This axle chassis connector 124 is connected to the front and rear of the frame 106 where an axle 202 protrudes through the wheel 126 allowing it to be positioned on the axle 202 .
[0031] The exploded view of FIG. 2 depicts the positioning of the wheel 126 onto the axle 202 , a wheel retaining washer 204 installed on the axle 202 and a wheel retaining pin 206 inserted in a hole through the axle 202 thus preventing the wheel 126 from departing during operations. The wheel retaining washer 204 is positioned between the wheel 126 and the wheel retaining pin 206 to prevent the wheel retaining pin 206 from interfering with the wheels 126 during normal operations. The wheel retaining pin 206 is known in the industry as a “cotter pin” which prevents the wheel 126 from departing the axle 202 . Other methods to prevent wheel 126 departure are well known to one skilled in the art and may be used to secure the wheel 126 .
[0032] The axle chassis connector 124 is rigidly affixed to the frame 106 by welding the axle chassis connector 124 to the frame 106 but one skilled in the art can choose other known methods for affixing the axle chassis connector 124 to the frame 106 . Additionally, the operator may want to lower or raise the frame 106 with respect to the shingle surface allowing the operator to position the heat closer to the surface of the shingles based on the outdoor weather conditions. This may be accomplished using other methods for affixing the wheel 126 s to the frame 106 instead of welding the axle chassis connector 124 directly to the frame 106 , such as installing standard push lawn mower height type adjustments. The height adjustment is accomplished by adjusting the front height adjustments 214 on both the front left and right side and the rear height adjustments 216 on the rear left and right side. The ability to raise and lower the thermal shingle sealing apparatus 100 allows the operator to control the loss of heat based on the wind and temperature conditions. This is one method to reduce the amount of heat loss. In addition to height adjustments, another method to reduce heat loss is to add skirts 208 .
[0033] FIG. 2 illustrates the preferred availability of a skirt 208 adjustably attached to the frame 106 . The skirt 208 has multiple adjustment slots 210 allowing the skirt 208 to be adjusted vertically enabling an operator to control the air flow under the frame 106 thereby retaining and maintaining the heat within the cavity 500 to provide uniform heating atop the shingles. Connectors protruding from the frame 106 extend through the skirt 208 at the adjustment slots 210 where wing nuts 212 are used to secure the skirts 208 in the desired position of the operator. Other methods may be used to attach the skirts 208 to the frame 106 in order to make readily adjustable. These skirts 208 prevent excessive air flow blowing under the frame 106 and removing heat from desired area with the result of the apparatus taking either longer to heat and bond the shingles or requiring more heat from the forced air propane heater 102 for bonding to occur.
[0034] FIG. 3 illustrates the handle 130 and its connection to the thermal shingle sealing apparatus 100 . The handle 130 is in a T-bar configuration whereupon the upper part of the T provides the operator controls for directing the movement of the apparatus over the shingles to help bond them. Also located at the intersection of the horizontal part of the T-bar intersection is a system control and displaying unit 220 for quick and easy access during normal operations.
[0035] The handle 130 is connected to the frame 106 by a handle collar 128 . The outer diameter of the handle 130 is less than the handle collar's 128 inner diameter and the handle 130 slips inside the handle collar 128 where it is secured in place by the friction of the handle retaining bolt 300 . This handle retaining bolt 300 prevents the handle 130 from coming out of the handle collar 128 and also prevents the handle 130 from rotating inside the handle collar 128 . Other methods of affixing a handle including, but not limited to, other methods of securing the handle 130 inside the handle collar 128 will be apparent to one skilled in the art.
[0036] A handle mount 302 then mounts the handle collar 128 to the frame 106 . The handle 130 and the handle collar 128 pivot around a handle collar mounting bolt 304 which extends horizontally through the handle mount 302 and through the handle collar 128 protruding through the other side of the handle collar 128 and the handle mount 302 and is secured in place by a standard fastener. This handle collar mounting bolt 304 allows the handle collar 128 to pivot up and down freely about the handle collar mounting bolt 304 enabling different operators of varying heights to control the thermal shingle sealing apparatus 100 .
[0037] FIG. 4 depicts all four wheels 126 attached to the frame 106 as viewed from above as was previously mentioned. FIG. 4 also shows the rear angle panel 306 that was previously mentioned but not depicted. The rear angle panel 306 is a companion panel to the front angle panel 118 . These panels work in concert to help project down and deflect the heated air from the forced air propane heater 102 .
[0038] FIG. 4 further describes the system control and display unit 220 , which has three central parts. First, it has a heat setting 400 where the heat settings are predetermined settings where a number corresponds to a specific heat output from the forced air propane heater 102 . Next, it has an over-temperature alarm 404 where the operator can set the alarm to notify operator when the shingle's temperature exceeds a maximum temperature to prevent damage to the shingles when the system is in use. The settings for the over-temperature alarm 404 could be set at the factory or by the operator on site providing more flexibility in the field. Finally, it has a temperature display 402 , which measures the temperature of the shingles on the trailing edge using a temperature sensor 504 mounted to a sensor mount 408 at the rear of the frame 106 next to the handle collar 128 . The system control and display unit 220 receives its information from heat sensor 504 via a sensor cable 406 . Alternately, the sensor cable 406 could be replaced with a transmitter/receiver system with the temperature sensor 504 sending signals to the system control and display unit 220 .
[0039] FIG. 5 is a bottom view of the thermal shingle sealing apparatus 100 , which illustrates the cavity 500 that is created by the heat disperser 104 as defined earlier in FIG. 1 . Additionally, this figure shows the blower 502 of the forced air propane heater 102 , where the blower 502 has a protective grill and a fan for producing the proper air flow to push the heat down onto the surface of the shingles. Also shown in this figure is a heat temperature sensor 504 , which is connected to the sensor mount 408 and the sensor cable 406 . This temperature sensor 504 is typically an infrared sensor, which measures the heat radiating from the shingles after the heat from the apparatus has been applied. The information obtained from the temperature sensor 504 determines when the alarm should be activated thereby alerting the operator to reduce the amount of heat being applied.
[0040] FIG. 6 is a bottom view of the thermal shingle sealing apparatus 100 with radiant heaters 600 . The radiant heaters 600 are suspended from the radiant heater supports 602 , which attach to both side panels 122 . Alternately, the radiant heaters 600 may be supported longitudinally by the radiant heater supports 602 , which would be connected to the front and back of the thermal shingle sealing apparatus 100 . The attachment points should allow the radiant heater supports 602 to be moved, enabling the radiant heaters 600 to be placed closer to the shingles to facilitate bonding or further away from the shingles to prevent damage.
[0041] FIG. 7 illustrates another embodiment of the present invention. While this embodiment could be used on any pitch of roof, it is specifically adapted for use on high-pitched roofs where the embodiment previously discussed herein was designed for lower pitched roofs because use of the previous embodiment would present safety concerns and would not produce the results of heating the sealant and bonding the shingles that is desired. The embodiment shown in FIG. 7 , like the previously-described embodiment, has three components upon which the discussion herein will focus: a forced air electric heater 700 , a disperser 702 and a chassis 704 .
[0042] The forced air electric heater 700 utilizes a blower 706 to force air through an upper blower tube 728 and a lower blower tube 732 into the forced air input 724 wherein the air is heated by heating elements 800 inside the disperser 702 . The air is moved across the heating elements 800 raising the temperature of the air in the disperser cavity 802 and the outgoing air to the desired temperature in order activate the sealant and bond the shingles. The blower 706 is powered by common household electricity through the use of a power cord 708 . The electricity supplied is used to control the airspeed from the blower 706 through an airflow control trigger 718 , which allows a operator to determine the amount of air being forced across the heating elements 800 and onto the shingles by the airflow control trigger 718 positions.
[0043] Additionally, the heat from the heating elements 800 is controlled by a controller 710 attached to the chassis 704 . The controller 710 has two operator controls and a display. The first operator control is the power switch 712 , the second operator control is the heat setting knob 714 , which may be set at various levels depending on the outdoor conditions under which the shingles are being installed and lastly is the temperature display 716 that displays a temperature from the temperature sensor 720 . The temperature sensor 720 is positioned on the trailing edge of the disperser 702 in order to determine whether the heat being applied to the shingles is at an acceptable level to activate the sealant and bond the shingles, too low to activate the sealant or in excess which could damage the shingles. This temperature sensor 720 is typically an infrared sensor, which measures the heat radiating from the shingles after the heat from the apparatus has been applied. A signal is sent from the temperature sensor 720 through a control cable 722 to the temperature display 716 on the controller 710 .
[0044] FIG. 7 further depicts the heat disperser 702 having a forced air input 724 and two wheels 734 that adjust to maintain the height of the disperser 702 above the shingles by wheel height adjustments 736 .
[0045] The chassis 704 in this embodiment comprises the body surrounding the blower 706 described as the chassis 704 , which includes a handle 726 , an upper blower tube 728 , a length adjustment sleeve 730 , and the lower blower tube 732 . These elements comprise a chassis 704 by which wheels 734 attach to the chassis 704 and the disperser 702 enabling the apparatus to be transported by a operator utilizing the handle 726 , positioned on the roof and moved up and down the roof sealing the shingles. This embodiment specifically addresses issues with high-pitched roofs that would not allow the first embodiment to be used due to safety concerns. A operator standing on a ladder as the shingles are being installed can move the apparatus to cover and activate the sealant of the newly installed shingles. Additionally, the wheels 734 attached to the disperser 702 may be adjusted to place the disperser 702 closer to or further from the shingles thereby preventing damage while bonding the shingles together.
[0046] FIG. 8 depicts the underside of the heat disperser 702 , an enclosure that creates a disperser cavity 802 where heat is produced by heating elements 800 affixed inside the heat disperser 702 and is spread over a focused area by the forced air from the blower 706 through the upper blower tube 728 and lower blower tube 732 to the forced air input 724 . The number of heating elements 800 , required is based on the amount of heat that is needed to be able to activate the sealant on the shingles.
[0047] FIG. 8 further depicts the wheel 734 and its component parts, an axle 804 , a wheel retaining washer 806 , and a wheel retaining pin 808 . The axle 804 protrudes through the wheel 734 and the wheel retaining washer 806 and the wheel retaining pin 808 is placed in a hole in the axle 804 securing the wheel 734 .
[0048] These two embodiments enable an operator to heat the sealant and allow the shingles to be bonded on a wide range of roofs varying in pitch as demonstrated by the first embodiment with the four-wheeled chassis apparatus for low-pitched roofs and the second embodiment with the handheld wheeled apparatus for high-pitched roofs, both of which are described above.
[0049] The purpose of the abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientist, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
[0050] While the invention has been shown, illustrated, described, and disclosed in terms of specific embodiments or modifications, the scope of the invention should not be deemed to be limited by the precise embodiments or modifications therein shown, illustrated, described, or disclosed. Such other embodiments or modifications are intended to be reserved especially as they fall within the scope of the claims herein appended. | A thermal shingle sealing apparatus for use in cool weather installations of thermally-activated shingles, the apparatus comprising a heat source having a fuel source, a burner, an ignition means adapted to light fuel from the fuel source to produce heat, and a controller adapted to regulate the heat produced; a heat disperser including an enclosure defining a cavity therein adapted to disperse heat from the heat source onto shingles; a chassis having a frame, and at least one wheel, whereby, the apparatus is placed on a roof atop the asphalt shingles and heat is applied to the shingles to activate the sealant, thereby bonding the shingles to one another in the cool temperatures providing nearly instant wind protection to the building owner in lieu of waiting for heat activation from the sun. sufficiently to activate sealant. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to door lock devices for motor vehicles, and more particularly, to automotive door lock devices of a type which has an interchanger-installed cover plate fixed to a lock proper for operatively connecting various external controllers, such as, outside door handle, inside door handle, locking knob and the like to a lockable latch mechanism of the lock proper.
2. Description of the Prior Art
Hitherto, various types of door lock devices have been proposed and put into practical use particularly in the field of wheeled motor vehicles.
One of them is shown in Japanese Patent First Provisional Publication 64-21186, which generally comprises a lock proper which has a lockable latch mechanism engageable with a striker fixed to a vehicle body and an interchanger-installed cover plate which is fixed to the lock proper for operatively connecting various external controllers of the door (such as, outside door handle, inside door handle, locking knob and the like) to the lockable latch mechanism of the lock proper.
The lock devices of this type can be commonly and widely used in various doors by only changing the cover plate.
However, the common usage of the lock devices of this type is not available in a field wherein two types of connecting members, viz., rod-type connecting member and cable-type connecting member, are selectively used for connecting the external controllers with the latch mechanism of the lock proper.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an automotive door lock device which can be used in both one field wherein the rod-type connecting member is used and another field wherein the cable-type connecting member is used.
According to a first aspect of the present invention, there is provided an automotive door lock device which comprises a lock proper having a latch mechanism installed therein; a main cover plate fixed to the lock proper, the main cover plate having therein an interchanger mechanism operatively engaged with the latch mechanism; a socket structure defined by the main cover plate, the socket structure having a terminal member of the interchanger mechanism exposed to an interior of the socket structure; an auxiliary cover plate having a shape to be detachably held by the socket structure and having an actuating member installed thereto, the actuating member being brought into an operative connection with the terminal member when the auxiliary cover plate is properly held by the socket structure; and latch means for achieving a latched engagement between the auxiliary cover plate and the socket structure when the auxiliary cover plate is fully inserted into the interior of the socket structure.
According to a second aspect of the present invention, there is provided an automotive door lock device which comprises a lock proper having a latch mechanism installed therein; a main cover plate fixed to the lock proper, the main cover plate having therein an interchanger mechanism operatively engaged with the latch mechanism; a single socket structure defined by the main cover, the socket structure having a terminal member of the interchanger mechanism exposed to an interior of the socket structure; a first auxiliary cover plate having a shape to be detachably held by the single socket structure and having a first actuating member installed thereto, the first actuating member being brought into an operative connection with the terminal member when the first auxiliary cover plate is properly held by the single socket structure; a second auxiliary cover plate having a shape to be detachably held by the single socket structure and having a second actuating member installed thereto, the second actuating member being brought into an operative connection with the terminal member when the second auxiliary cover plate is properly held by the single socket structure; and latch means for achieving a latched engagement between either one of the first and second auxiliary cover plates and the single socket structure when the one auxiliary cover plate is fully inserted into the interior of the socket structure.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective view of an automotive door lock device according to the present invention, showing a condition wherein two types (viz., rod-connector type and cable-connector type) of auxiliary cover plates are separated from a main cover plate;
FIG. 2 is a side view of the automotive door lock device having the rod-connector type auxiliary cover plate coupled therewith;
FIG. 3 is a front view of the automotive door lock device in the assembled condition;
FIG. 4 is a back view of the main cover plate;
FIG. 5 is a vertically sectional view of the main cover plate with which the rod-connector type auxiliary cover plate is properly coupled;
FIG. 6 is a vertically sectional view of the main cover plate having the rod-connector type auxiliary cover plate separated therefrom;
FIG. 7 is a vertically sectional but partial view of the main cover plate with which the cable-connector type auxiliary cover plate is coupled; and
FIG. 8 is a vertically sectional view of the main cover plate having the cable-connector type auxiliary cover plate separated therefrom.
DETAILED DESCRIPTION OF THE INVENTION
In the following, the automotive door lock device of the present invention will be described in detail with reference to the accompanying drawings.
Referring to the drawings, particularly FIG. 1, there is shown the automotive door lock device according to the present invention.
The lock device generally comprises a lock proper 1 mounted to an automotive door (not shown) and a unique cover plate 2 mounted to the lock proper 1.
The lock proper 1 has therein a known lockable latch mechanism which includes a latch plate engageable with a striker fixed to a vehicle body, and a locking plate engageable with the latch plate to lock the same at the door latching position.
The unique cover plate 2 comprises a main cover plate 3 which is fixed to the lock proper 1 and two auxiliary cover plates 4 and 5 which are selectively coupled with the main cover plate 3.
The auxiliary cover plate 4 is constructed to connect a rod-type connecting member to the lock proper 1, while the other auxiliary cover plate 5 is constructed to connect a cable-type connecting member to the lock proper 1. Thus, hereinafter, these two auxiliary cover plates will be referred to as "rod-connector type auxiliary cover plate" and "cable-connector type auxiliary cover plate" respectively.
As is seen from FIG. 1, the main cover plate 3 comprises a flat major portion 3a which is intimately attached to the lock proper 1, and first and second raised portions 3b and 3c which are formed at one side of the flat major portion 3a. The second raised portion 3c is formed with a connector part 6 which has a rectangular aperture 6a formed therein.
As will become apparent as the description proceeds, with the connector part 6, there is selectively coupled either one of the rod -connector type and cable-connector type auxiliary cover plates 4 and 5.
The connector part 6 comprises opposed larger flat walls (no numerals) and opposed smaller walls 6b and 6c. The smaller walls 6b and 6c are respectively formed with resilient pawls 6d and 6e each being projected inward.
As is seen from FIG. 6, the rod-connector type auxiliary cover plate 4 is shaped to match with the rectangular aperture 6a of the connector part 6 of the main cover plate 3. The auxiliary cover plate 4 has opposed side walls which have respective stopper gaps 4a and 4b. Within the auxiliary cover plate 4, there is pivotally installed through a pivot shaft 19 an inside lever 18 which has one end 18a and the other end 18b. The one end 18a is pivotally connected to a rod type connecting member 20 (see FIG. 2) which extends from a door inside handle (not shown) mounted to the door. As will be described hereinafter, the other end 18b of the inside lever 18 is brought into an operative connection with an end portion 8c of an after-mentioned outside lever 8 when the auxiliary cover plate 4 is properly coupled with the main cover plate 3.
As is seen from FIG. 8, also the cable-connector type auxiliary cover plate 5 is shaped to match with the rectangular aperture 6a of the connector part 6 of the main cover plate 3. The auxiliary cover plate 5 has opposed side walls which have respective stopper gaps 5a and 5b. Within the auxiliary cover plate 5, there are formed a cable retaining portion 5c and a curved guide passage 5d. The cable retaining portion 5c retains an end of an outer casing 21a of a cable 21, while the curved guide passage 5d slidably receives therein an inner cable 21b of the cable 21. The cable 21 extends from the door inside handle mounted to the door. The inner cable 21b has at its terminal end a round stopper 21c fixed thereto.
As is seen from FIG. 4, the main cover plate 3 is provided, at an inner surface of the flat major portion 3a facing the lock proper 1, with both an outside lever 8 which is pivotally connected thereto through a pivot shaft 7 and a first lock lever 10 which is pivotally connected thereto through another pivot shaft 9. The outside lever 8 has one end 8a pivotally connected to a rod-like connecting member extending from a door outside handle (not shown) mounted to the door, while the first lock lever 10 has one end 10a pivotally connected to a rod-like connecting member extending from a key cylinder (not shown) mounted to the door.
The outside lever 8 is biased to pivot in a clockwise direction in FIG. 4 by a spring The spring 11 has a coiled portion received in a round recess 7a defined by the pivot shaft 7. The spring 11 has one end hooked to a raised part 8b of the outside lever 8 and the other end hooked to a raised portion 3d of the main cover plate 3.
A first sub-lever 13 is pivotally connected at its one end to the outside lever 8 through a pin 12. As shown, the pin 12 is connected to a portion of outside lever 8 defined between the end 8a and the pivot shaft 7. The pin 12 has an extension slidably guided by an arcuate guide slot 3e formed in the main cover plate 3. The other end portion 8c of the outside lever 8 is exposed to the rectangular aperture 6a of the connector part 6 of the main cover plate 3.
For the reason which will become apparent hereinafter, the other end portion 8c of the outside lever 8 is formed with a vertical slit (not shown).
The first sub-lever 13 is formed at the other end portion thereof with an elongate slot 13a with which one end portion 14a of a second sub-lever 14 is slidably engaged. The first sub-lever 13 is formed between the pivoted part and the elongate slot 13a with an engaging portion 13b which is engageable with an open lever 17. The open lever 17 is connected to the locking plate of the lock proper 1 to pivot therewith. The second sub-lever 14 is linearly slidably supported by the main cover plate 3, that is, the second sub-lever 14 is movable upward and downward as viewed in FIG. 4.
As is seen from FIG. 4, the first lock lever 10 has one end 10b pivotally connected to the other end portion 14b of the second sub-lever 14. Thus, upon operation of the key cylinder of the door, the first and second sub-levers 13 and 14 are moved between their unlocking positions as shown in FIG. 4 and their locking positions (not shown). The locking positions are achieved when the first sub-lever 13 is pivoted clockwise from the position of FIG. 4. The second sub-lever 14 has a waved leaf spring 15 fixed thereto. Upon upward and downward movement of the second sublever 14, the spring 15 resiliently contacts against a raised portion 3f of the main cover plate 3 thereby to make the movement in a snap action manner.
As is seen from FIG. 5, within the first raised portion 3b of the main cover plate 3, there is pivotally installed through a pivot shaft 22 a second lock lever 16. The second lock lever 16 is pivoted between its locking and unlocking positions in response to the pivotal movement of the above-mentioned first lock lever 10. One end portion 16a of the second lock lever 16 is pivotally connected to a rod-like connecting member (not shown) which extends from the manual locking knob (or an actuator of a power device) mounted to the door. The other end portion 16b of the second lock lever 16 is pivotally connected to a bent portion 14c of the second sub-lever 14, so that upon operation of the locking knob, the first lock lever 10 and the first and second sub-levers 13 and 14 are moved between their locking positions and unlocking positions.
In the following, operation of the automotive door lock device of the invention will be described with reference to the drawings, particularly FIG. 4.
For ease of understanding, the description will be commenced with respect to a so-called "unlocked latched condition" of the door wherein the latch plate is fully engaged with the striker to latch the door to the vehicle body. Under this condition, the first and second lock levers 10 and 16 assume their unlocking positions as shown in FIG. 4 and the first and second sub-levers 13 and 14 assume the positions as shown in FIG. 4.
When now the door outside handle is manipulated for the purpose of opening the door, the outside lever 8 is pivoted in a counterclockwise direction in FIG. 4. With this, the first sub-lever 13 is moved rightward having the pin 12 guided by the arcuate guide slot 3e of the main cover plate 3. Due to this rightward movement of the first sub-lever 13, the engaging portion 13b of the same abuts against and pivots the open lever 17 and thus the latched engagement between the locking plate and the latch plate is canceled. Thus, the door becomes ready for opening.
When, with the first and second lock levers 10 and 16 assuming their unlocking positions as shown in FIG. 4, the key cylinder is manipulated by a key plate from the outside of the door for the purpose of locking the door, the first lock lever 10 is pivoted clockwise in FIG. 4 and thus the second sub-lever 14 is moved downward. With this, the first sub-lever 13 is pivoted clockwise about the pin 12 moving the engaging portion 13b thereof away from the traveling path of the open lever 17. Under this condition, manipulation of the door outside handle fails to induce engagement of the engaging portion 13b with the open lever. Thus, even when the door outside handle is manipulated, the door can not be opened. It is to be noted that this door locking condition is similarly achieved when the locking knob connected to the second lock lever 16 (see FIG. 6) is manipulated.
In the following, the process for coupling the auxiliary cover plate 4 or 5 (viz., rod-connector type or cable-connector type auxiliary cover plate) with the connector part 6 of the main cover plate 3 will be described with reference to the drawings.
IN CASE OF ROD-CONNECTOR TYPE 4
As is seen from FIG. 6, the auxiliary cover plate 4 is inserted into the rectangular aperture 6a of the connector part 6 in the direction of the arrow. When the auxiliary cover plate 4 is fully inserted into the aperture 6a, the resilient pawls 6d and 6e of the connector part 6 are brought into engagement with the stopper gaps 4a and 4b of the auxiliary cover plate 4 to complete the coupling of the auxiliary cover plate 4 and the main cover plate 3, as is seen in FIG. 5. Upon this, the other end 18b of the inside lever 18 is positioned below the end portion 8c of the outside lever 8 installed in the main cover plate 3. That is, operative connection between the inside lever 18 and the outside lever 8 is achieved. That is, when the door inside handle is manipulated for the purpose of opening the door, the other end 18b of the inside lever 18 raises the end portion 8c of the outside lever 8 inducing a counterclockwise movement of the outside lever 8 (see FIG. 8), which causes the door to become ready for opening, as has been mentioned hereinabove.
IN CASE OF CABLE-CONNECTOR TYPE 5
As is seen from FIG. 8, the auxiliary cover plate 5 is inserted into the rectangular aperture 6a of the connector part 6 in the direction of the arrow. When the auxiliary cover plate 5 is fully inserted into the aperture 6a, the resilient pawls 6d and 6e of the connector part 6 are brought into engagement with the stopper gaps 5a and 5b of the auxiliary cover plate 5 to complete the coupling of the auxiliary cover plate 5 and the main cover plate 3, as is seen from FIG. 7. Upon this, the terminal end portion of the inner cable 21b of the cable 21 is put into the vertical slit of the end portion 8c of the outside lever 8 having the round stopper 21c left below the end portion 8c, as shown. That is, operative connection between the inner cable 21b and the outside lever 8 is achieved. That is, when the door inside handle is manipulated for the purpose of opening the door, the round stopper 21c of the cable 21 raises the end portion 8c of the outside lever 8. As is described hereinabove, such raising causes the door to become ready for opening.
As is understood from the foregoing description, the interchanger-installed cover plate used in the present invention is constructed to connect with either of the rod-type connecting member 20 and the cable type connecting member 21. Thus, the automotive door lock device of the present invention can be commonly and widely used in various types of doors by only selecting the auxiliary cover plate 4 or 5. | An automotive door lock device comprises a lock proper having a latch mechanism installed therein. A main cover plate is fixed to the lock proper. The main cover plate has therein an interchanger mechanism operatively engaged with the latch mechanism. A socket structure is defined by the main cover plate. The socket structure has a terminal member of the interchanger mechanism exposed to an interior of the socket structure. An auxiliary cover plate has a shape to be detachably held by the socket structure and has an actuating member installed thereto. The actuating member is brought into an operative connection with the terminal member when the auxiliary cover plate is properly held by the socket structure. | 8 |
This is a Continuation-In-Part of Utility patent application Ser. No. 08/414,271 filed Mar. 31,1995, (now U.S. Pat. No. 5,557,891), and of Provisional patent application Ser. No. 60/002,017 filed Aug. 8, 1995.
TECHNICAL FIELD
The present invention relates to gutter systems which collect rain water at the lower edges of sloping building roofs, and to gutter protection systems which prevent the accumulation of debris in gutter systems during use, while allowing water to enter thereto. More particularly the present invention relates to hemmed gutter protection system design in combination with mounting clip designs, which simplify installation of gutter protection systems on K-style, Half-Round and Vinyl gutter systems.
BACKGROUND
The use of gutter systems at the lower edges of sloping building roofs to accumulate and direct rain water running-off thereof into downspouts for disposal at intended locations, is known. A problem associated with typical gutter systems during use thereof, however, is that they accumulate debris therein, such as leaves and twigs etc., and become clogged. This can occur as typical gutter systems are open at their upper ends. Clogged gutter systems can overflow and in addition to the nuisance created by the failure of said clogged gutter systems to direct water to intended downspouts for disposal at an intended location, can cause water to come into contact fascia and soffits etc. of the buildings to which they are applied. Constant contact with said water can cause damage to said fascia and soffits etc. In severe cases such, as during freezing weather, clogged gutters can develop ice damns, leading to the presence of sufficient weight in said gutter systems so as to actually dislodge them from said associated building. In even minor cases of clogging users must face the inconvenience of having to clean accumulated debris from the said gutter systems.
Inventors have noted the identified problem and responded with numerous systems which to lesser or greater degrees serve to overcome the identified problems. A very early, (1898), U.S. Pat. No. 603,611 to Nye, for instance describes, in the language of Nye, "an eves hanging trough having its inner wall carried upward above said trough, thence outward over said trough, and backward to the line of attachment to the roof, all in gentle curves . . . ". The Nye system operates by, via capillary action, directing water which runs off the roof of a building to which it is attached onto the portion of the inner wall thereof which is carried outward over the trough thereof and then into said trough, while simultaneously sweeping leaves and other debris off the system, and thereby preventing them from entering said trough. The Nye system is best visualized as comprising a backward "S" shape in side cross section, the upper edge of which is mounted to the eves of a building to which said Nye system is affixed. Another and more recent (1985) U.S. Pat. No. 4,493,588 to Duffy describes a system essentially similar to the Nye system, in which "[T] the curved portion overhangs the trough and a generally vertical screen extends between the trough and the curved portion . . . ". That is, a screen is present to further prevent leaves, twigs and other debris from entering the trough thereof. The upper edge of the Duffy system mounts under shingles on a roof of a building to which said system is affixed. Another more recent (1988) variation of a gutter system which provides benefits similar to those provided by the Nye invention is described in U.S. Pat. No. 4,757,649 to Vahldieck. The Vahldieck invention system comprises "a continuous double-curved convolute curve, generated on a first and second radius, which extends from the back wall, down short of the inside wall of the trough, and inward over the trough". The Vahldieck system is best visualized as being essentially of a squared "C" shape in side cross section, with the edge of the lower extent of said squared "C" shape being bent upward to form said trough, and with the with the upper extent of said squared "C" shape being curved downward in two stages, the second stage of which is defined by a tighter radius of curvature than in the first. In use, water running-off a roof of a building to which the Vahldieck system has been affixed follows, by capillary action, the double curved upper extent of said squared "C" shape and falls into the formed trough. Again, leaves and other debris are directed to locations other than into said trough. A 1989 Patent to Rose et al., U.S. Pat. No. 4,858,396 provides yet another variation on the same general theme "wherein a substantially flat extension which passes beneath the eves terminates in a free edge adjacent a narrow slot in an apex portion of an extended synthetic polymeric tube".
The Patents surveyed to this point serve to provide systems which are particularly applicable to new construction. That is, the Nye, Duffy, Vahldieck and Rose et al. systems provide gutters as a part thereof. Said systems are also applicable as replacements for existing gutter systems, but, said systems are not particularly relevant for retro-fit application to existing gutter systems. Inventors have however, during the 1980's and on into the 1990's, also provided numerous systems applicable for retro-fit to existing gutter systems. For instance, U.S. Pat. Nos. 4,404,775, 4,497,146 and 4,796,390 to Demartini describe systems ". . . which comprise a deflector having a sloped portion, the top edge region of which is adapted for juxtaposition to the roof shingles, and the bottom edge region of which is arcuate through a large radius cross-section. In such embodiments, the farthest outward extension is outside the outermost edge of the associated rain gutter and the lower edge is positioned between the edges of the rain gutter. Embodiments include means for attenuating the force of water and reducing the localized concentrating of water flowing thereover, such as longitudinal ridges and/or means for improving the surface wettability". The system can be visualized as essentially being "hook-shaped", (in side cross-section), in which, during use, the tip of the "hook" is oriented so as to face downward between the edges of an associated gutter system, and the shaft of said "hook" is positioned beneath shingles on the lower edge of the roof of a building to which the system is applied. Importantly, the Demartini Patents also describe numerous mounting means for use in mounting the described system to existing gutter systems. Another U.S. Pat. No. 4,455,791 to Elko et al., provides another system for similar use in retro-fit to existing gutter systems. "A protective structure for a gutter includes an elongated, impervious sheet wide enough to extend across at least about 90% of the width of the gutter and up under a lower edge of roofing material. The outer edge of the cover curls downwardly and the water follows the curvature by surface tension to cascade into the gutter. The cover may be held in place by straps that extend transversley across it and have one end engaged under the inwardly turned lip of the gutter and the other end engaged under roofing material". Alternatively clips can also be used for mounting the cover. Another Patent which describes a system for use in retro-fit to existing gutter systems is U.S. Pat. No. 5,016,404 to Briggs. This system provides that "[A] a sheet layer has an edge beneath the shingles and curves in front of and below the fascia above the gutter mouth forming a relatively small entrance region with the gutter. The apex of the curve extends beyond the gutter so that debris carried by water run off falls to the ground while the run off flows around the layer into the gutter". U.S. Pat. No. 5,189,849 to Collins describes a two piece roof rain gutter debris shield/run-off water control system. In the words of Collins, ". . . a roof slope adaptor and its alternate means accommodate every and all roof slope/gutter juxtaposition, thereby eliminating traditional installation problems, a support stabilizer functions to provide stability and rigidity, while preserving the integrity of critical embodiment dimensions, a slope adaptor affixation clip means provides a plurality of attachment means". In essence, a gutter shield embodiment is attached to and above a gutter by means of a support stabilizer, and provides a horizontally oriented capillary cap portion at an upper aspect thereof. A roof slope adaptor provides continuity between the roof of a building to which the system is affixed and said horizontally oriented capillary cap portion. The upper edge of said roof slope adaptor is placed under shingles at the lower edge of said roof and the lower edge thereof rests atop said horizontally oriented capillary cap portion.
Additional Patents describe the use of slots or openings in gutter shield systems. For instance a Patent to Otto, U.S. Pat. No. 4,866,890 describes "[A] a cover member for mounting on a conventional rain gutter on a building structure, consisting of a one piece thin, longitudinal shield to be inserted under the shingles of the roof and having a serrated outer edge which is bent downward a short distance back from its edge so that it can rest on the flat portion of the inner wall at the top lip of the qutter, the serrations providing small openings which water from the roof can run into the gutter and exclude pine straw or leaves from entering the gutter". Another U.S. Pat. No. 4,876,827 to Williams describes that "[T] the gutter assembly includes a curved water shed surface with a plurality of openings along its vertical portion which selectively allow the water to enter the gutter positioned below while excluding pine needles, leaves and other debris from engaging the gutter". U.S. Pat. No. 5,181,350 to Meckstroth describes that "[A] an elongated strip of extruded plastics material includes a generally flat longitudinally extending inner portion adapted to project under the shingles of a roof and a longitudinally extending outer portion adapted to seat on the outer edge portion of a rain gutter and project outwardly from the gutter to form a drip lip spaced from the gutter. A longitudinally extending intermediate portion of the strip integrally connects the inner portion to the outer portion and has a rounded nose surface above a U-shaped channel for directing water from the inner portion into the gutter and for deflecting leaves and other debris onto the outer portion of the strip for dropping them from the drip lip". U.S. Pat. No. 4,571,896 to Condie describes that "[A] a gutter assembly is provided which comprises an elongated, preferably transversely flexible sheet which when in an installed position extends along a building roof adjacent an edge of it, while extending below the roof edge. A pipe is provided which has a lengthwise extending slot which accommodates a side edge of the sheet through it adjacent an edge of the slot, while leaving room for entry of only water through the slot". "Such a gutter assembly inhibits entry of foreign matter into the pipe". A similar pipe arrangement is described in U.S. Pat. No. 4,551,956 to Axford. A Patent to Kuhns, U.S. Pat. No. 5,216,851 describes a system with an extended flat portion which does not contain any apertures and serves to close the open top of a gutter to which it is applied. The extended flat portion is connected to an apertured portion, which apertures portion connects to the upper lip of the front wall of a gutter via a lip portion thereof. Said apertures are shaped to direct water into the associated gutter while causing debris to simply flow over the outer front wall of the gutter. A Patent to Olsen, U.S. Pat. No. 4,631,875 describes a system with a generally planar surface which has a plurality of spaced parallel apertures which allow the entry of water into an underlying gutter. Patents to Way Sr. et al, U.S. Pat. No. 4,937,986 and to Pond, U.S. Pat. No. 2,847,949 describe gutter protection systems which provide an element which projects at a slope opposite to that of a roof to which the gutter they protect is attached, so that water exiting thereonto is slowed thereby. Both provide perforations in the oppositely sloped element so that water can enter to an underlying gutter.
The above survey of Patents shows that numerous systems for preventing clogging of gutter systems have been invented and Patented. Users of many of said systems, however, have found that there remains need for improvement, particularly as regards ease of system installation and effective operation. The present invention provides a system which demonstrates improvement over the known identified existing art.
DISCLOSURE OF THE INVENTION
The present invention is basically a gutter protection system which in use is affixed between a sloped building roof and a forward upper aspect of a gutter system. Said gutter system being affixed to a sloped roof building at a lower edge of, and below, said sloped roof. A major focus of the said gutter protection system is a hemmed section comprising, as viewed in right side elevation, a first downward and to the left projecting length of construction material which is merged into a first upward and to the right projecting length of construction material by way of an essentially one-hundred-eighty degree relatively tight bend. In use said gutter protection system further comprises at least one mounting clip secured at said hemmed section, said mounting clip being used in interfacing said gutter protection system to said forward upper aspect of said gutter system. Said at least one mounting clip can be placed so as to avoid gutter system mounting spikes and is provided limited three-dimensional rotational capability within said hemmed section.
A preferred embodiment of the present invention gutter protection system, in use, is affixed between a sloped building roof and a forward upper aspect of a gutter system, which gutter system is affixed to a sloped roof building at a lower edge of, and below, said sloped roof. Said gutter protection system, as viewed in right side elevation, prior to affixing to a sloped roof building, generally comprising a hemmed section, said hemmed section comprising a first downward and to the left projecting length of construction material which is merged into a first upward and to the right projecting length of construction material by way of an essentially one-hundred-eighty degree relatively tight bend. Said first upward and to the right projecting length of construction material merging, via a relatively tight bend, into a downward and to the right projecting length of construction material. Said downward and to the right projecting length of construction material being merged, via a relatively tight bend, into an upward and to the right projecting length of construction material. Said upward and to the right projecting length of construction material being comprised of openings which allow water flowing thereonto in use to pass therethrough and enter an underlying gutter system, and being merged, via a relatively tight bend, into an upward and to the left projecting length of construction material to a length such that a leftmost positioned end thereof is vertically above said first upward and to the right projecting length of construction material. Said upward and to the left projecting length of construction material being merged, via a relatively gradual bend, into a left major horizontally projecting length of construction material. Said left major horizontally projecting length of construction material being merged, via a relatively gradual bend, into an upward and to the right projecting length of construction material. Said upward and to the right projecting length of construction material being merged, via a relatively gradual bend, into a downward and to the left projecting length of construction material. Said downward and to the left projecting length of construction material being merged, via a relatively gradual bend, into an upward and to the left projecting length of construction material. Said upward and to the left projecting length of construction material being merged, via a relatively gradual shaped bend, into a right major horizontally to the right projecting length of construction material, and said right major horizontally to the right projecting length of construction material being merged into a horizontally to the left projecting length of construction material via an essentially one-hundred-eighty-degree bend.
In all preferred embodiments, said at least one mounting clip is secured to the hemmed section by causing a projecting lip thereof to be present between the downward and to the left and the upward and to the right lengths of construction material which form said hemmed section.
In the case where a "K-Style" gutter system is present, said mounting clip comprising a projecting lip, said projecting lip being projected upward and to the right, as viewed in right side elevation. Said projecting lip being merged into an arcuate shaped section of construction material which opens generally to the left, by way of a downward and to the right projecting length of construction material, and said arcuate shaped section of construction material is merged into a second upward and to the right projecting length of construction material, optionally via an essentially vertically upward projecting length of construction material. Said second upward and to the right projecting length of construction material is merged into a second downward and to the right length of construction material. The mounting clip elements beyond said projecting lip serving to facilitate interfacing to the forward upper aspect of a "K-style" gutter system in use.
In the case where a "Half-Round" gutter system is present, said mounting clip is secured thereto by causing a projecting lip thereof to be present between the downward and to the left and the upward and to the right lengths of construction material which form said hemmed section. Said projecting lip being projected upward and to the right, as viewed in right side elevation, and being merged into an open arcuate shaped section of construction material which opens generally downward, by way of a downward and typically to the left projecting length of construction material. At least one side said open arcuate shaped section of construction material is present a downward and outward, from a central position within said mounting clip, projecting length of construction material, said at least one mounting clip elements beyond said projecting lip serving to facilitate interfacing to the forward upper aspect of a "half-round" gutter system in use.
In the case where a vinyl gutter system is present said mounting clip is secured thereto by causing a projecting lip thereof to be present between the downward and to the left and the upward and to the right lengths of construction material which form said hemmed section. Said projecting lip being projected upward and to the right, as viewed in right side elevation, and being merged into a common point, by a downward and typically to the left projecting length of construction material. From said common point there are projected a right and a left leg. Said right leg comprises a downward and to the right length of construction material, said downward and to the right length of construction material being merged into an arcuate shaped section of construction material which opens generally to the left, said arcuate shaped section of construction material which opens to the left being merged into an arcuate shaped section of construction material which opens generally to the right. Said left leg comprises a downward and to the left projecting length of construction material. At the end of at least said left leg there is present a length of construction materials which projects generally downward and outward from said common point, said mounting clip elements beyond said projecting lip serving to facilitate interfacing to the forward upper aspect of a "vinyl" gutter system in use.
It is to be understood that a mounting clip is secured to said hemmed section comprised of a first downward and to the left projecting length of construction material which is merged into a first upward and to the right projecting length of construction material by way of an essentially one-hundred-eighty degree bend, by causing an upward and to the right projecting lip thereof to be present between the downward and to the left and the upward and to the right lengths of construction material which form said hemmed section. As viewed from above, it should be appreciated, said mounting clip can be rotated through some angle without being removed from said hemmed section, said rotation serving to facilitate installation of said gutter protection system to gutter systems which present with non-uniform forward upper aspects. As viewed in frontal elevation, it should be appreciated that said mounting clip can rotate through some limited angle by causing a lower portion of said hemmed section to bend.
A method of affixing a gutter protection system to a sloped roof building comprising the steps of:
a. Providing a gutter protection system as described infra herein.
b. Securing at least one mounting clip presenting with a projecting lip to said gutter protection system, by causing a projecting lip thereof to be present between the first downward and to the left and the first upward and to the right lengths of construction material which form said hemmed section.
c. Causing said left major horizontally to the right projecting length of construction material to assume an angle with respect to said major right horizontally to the right projecting length of construction material by a bending about intervening gutter protection system elements, said angle being selected to match the slope of said sloped building roof.
d. Simultaneously causing said at least one mounting clip to interface to a forward upper aspect of a gutter system which is affixed to said building at the edge of, and below, said sloped roof, and said right horizontally to the right projecting length of construction material to be inserted beneath a first row of shingles present at a lower extent of said sloped roof.
The present invention system will be better understood by reference to the Detailed Description Section herein, in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
A purpose of the present invention is to provide a gutter protection system which prevents debris from entering to an underlying gutter system in use, while allowing water to enter thereto.
Another purpose of the present invention is to provide a gutter protection system of a design which facilitates easy mounting thereof to a sloped roof building.
Yet another purpose of the present invention is to provide mounting clips which are of designs which facilitate mounting of the present invention gutter protection system to "K-type", "Half-round" and "Vinyl" gutter systems.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 generally shows a gutter protection system of the present invention mounted to gutter system present at a lower edge of a building sloped roof.
FIG. 2a shows a hemmed section of a present invention gutter protection system for use into which projecting lips of mounting clips are secured during use.
FIG. 2b shows a projecting lip of a mounting clip secured in a present invention gutter protection system hemmed section.
FIG. 3a shows a right side elevational profile of a preferred embodiment of a present invention gutter protection system.
FIG. 3b shows holes in a section of the gutter protection system of FIG. 3a through which water can pass into an underlying gutter during use.
FIG. 4 shows a mounting clip appropriate for use in mounting the gutter protection system of FIG. 3a to a "Type-K" gutter system.
FIG. 5 shows a mounting clip appropriate for use in mounting the gutter protection system of FIG. 3a to a "Half-Round" gutter system.
FIG. 6 shows a mounting clip appropriate for use in mounting the gutter protection system of FIG. 3a to a "Vinyl" gutter system.
FIGS. 7a and 7b demonstrate the flexibility provided by mounting clip projecting lip and gutter protection system hemmed section coordination, in that the projecting lip can essentially rotate a bit within said hemmed section.
DETAILED DESCRIPTION
Turning now to the Drawings, it is indicated in FIG. 1 that the present invention is basically a gutter protection system (GPS) which in use is affixed between a sloped building roof (SR) and a forward upper aspect (FA) of a gutter system (GS). Said gutter system (GS) being affixed to a sloped roof building at a lower edge of, and below, said sloped roof.
FIG. 2a shows that a major focus of the said gutter protection system is a hemmed section comprising, as viewed in right side elevation, a first downward and to the left projecting length of construction material (A) which is merged into a first upward and to the right projecting length of construction material (C) by way of an essentially one-hundred-eighty degree relatively tight bend (B). In use said gutter protection system further comprises at least one mounting clip secured at said hemmed section, said mounting clip being used in interfacing said gutter protection system to said forward upper aspect of said gutter system. FIG. 2b shows an expanded view of the gutter protection system (GPS) of FIG. 2a with a mounting clip (MCK), (see FIG. 4), projecting lip (PLK) secured in the hemmed section (HS), said mounting clip (MCK) being shown situated with respect to the upper forward portion of a gutter system (GS), as generally shown in FIG. 1. It should be appreciate that said projecting lip (PLK) can rotate in said hemmed section (HS), (in the plane of the paper as shown), to a limited degree by causing the lower portion of said hemmed section to bend downward, (indicated by the dotted and solid (A) lengths of construction material in FIG. 2a), and by effecting bending between, for instance, elements (PLK) and (AS1K) in FIG. 2b. This provides mounting facilitating capability where a gutter system is of irregular shape.
FIG. 3a shows that a preferred embodiment of the present invention gutter protection system can be disclosed by description of a right side elevational view thereof, prior to mounting thereof to a sloped roof building. Such a right side elevational view provides that said first downward and to the left projecting length of construction material (A) which is merged into a first upward and to the right projecting length of construction (C) material by way of an essentially one-hundred-eighty degree bend (B) involving construction material of approximately 0.093 inches long, is approximately 0.346 inches long, and said first upward and to the right projecting length of construction material (C), being approximately 0.383 inches long and merges, via a relatively tight bend (D) involving construction material of approximately 0.039 inches long, into a downward and to the right projecting length of construction material (E) of approximately 0.544 inches long. Said downward and to the right projecting length of construction material (E) is merged, via a relatively tight bend (F) involving construction material of approximately 0.0.086 inches long, into an upward and to the right projecting length of construction material (G) of approximately 0.231 inches long. Said upward and to the right projecting length of construction material (G) is comprised of openings (GH) (see FIG. 3b), which allow water flowing thereonto in use to pass therethrough and enter an underlying gutter system, and is merged, via a relatively tight bend (H) involving construction material of approximately 0.0.085 inches long, into an upward and to the left projecting length of construction material (I) of approximately 0.841 inches long, said length providing that a leftmost positioned end thereof, (at (J)), is vertically above said first upward and to the right projecting length of construction material (C). Said upward and to the left projecting length of construction material (I) being merged, via a relatively gradual bend (J) involving construction material of approximately 0.25 inches long, into a left major horizontally projecting length of construction material (K) of approximately 3.435 inches long. Said left major horizontally projecting length of construction material (K) is merged, via a relatively gradual bend (L) involving construction material of approximately 0.014 inches long, into an upward and to the right projecting length of construction material (M) of approximately 0.271 inches long. Said upward and to the right projecting length of construction material (M) is merged, via a relatively gradual bend (N) involving construction material of approximately 0.183 inches long, into a downward and to the left projecting length of construction material (O) of approximately 0.245 inches long. Said downward and to the left projecting length of construction material (O) is merged, via a relatively gradual bend (P) involving construction material of approximately 0.019 inches long, into an upward and to the left projecting length of construction material (Q) of approximately 0.125 inches long. Said upward and to the left projecting length of construction material (Q) is merged, via a relatively gradual shaped bend (R) involving construction material of approximately 0.139 inches long, into a right major horizontally to the right projecting length of construction material (S) of approximately 3.689 inches long, and said right major horizontally to the right projecting length of construction material (S) is merged into a horizontally to the left projecting length of construction material (U) of approximately 0.220 inches long via an essentially one-hundred-eighty-degree bend (T) involving construction material of approximately 0.104 inches long.
It is to be understood that the provided length dimensions are provided as demonstrative, and are not to be interpreted as limiting.
Continuing, in all preferred embodiments, said at least one mounting clip is secured to the hemmed section by causing a projecting lip thereof to be present between the downward and to the left and the upward and to the right lengths of construction material which form said hemmed section.
FIG. 4 shows that, in the case where a "K-Style" gutter system is present, said mounting clip (MCK) comprises a projecting lip, said projecting lip (PLK) being projected upward and to the right, as viewed in right side elevation. Said projecting lip (PLK) is caused to be present between the downward and to the left (A) and the upward and to the right (C) lengths of construction material which form said hemmed section in use. Said projecting lip (PLK) is merged into an arcuate shaped section (AS1K) of construction material which opens generally to the left, by way of a downward and to the right projecting length of construction material (DR1K), and said arcuate shaped section (AS1K) of construction material is merged into a second upward and to the right projecting length of construction material (UR1K) via an essentially vertically upward projecting length of construction material (UR2K). Said second upward and to the right projecting length of construction material (UR1K) is merged into a second downward and to the right length of construction material (DR1K'). Note that said essentially vertically upward projecting length of construction material (UR2K) can be eliminated in a modified embodiment and/or element (AS1K) can be more arcuate in shape with element (DR1K) less pronounced, (as shown in FIG. 2 for instance). The mounting clip elements beyond said projecting lip serving to facilitate interfacing to the forward upper aspect of a "K-style" gutter system in use.
Turning now to FIG. 5, in the case where a "Half-Round" gutter system is present, said mounting clip (MCR) is shown as secured thereto by causing a projecting lip (PLR) thereof to be present between the downward and to the left (A) and the upward and to the right (C) lengths of construction material which form said hemmed section. Said projecting lip (PLR) being projected upward and to the right, as viewed in right side elevation, and being merged into an open arcuate shaped section (AS1R) of construction material which opens generally downward, by way of a downward and typically to the left projecting length of construction material (DL1R). At least one side said open arcuate shaped section of construction material is present a downward and outward, (DO1R) from a central position within said mounting clip, projecting length of construction material, said at least one mounting clip elements beyond said projecting lip serving to facilitate interfacing to the forward upper aspect of a "half-round" gutter system in use. In particularly, the downward and outward projecting length of construction material ((DO1R) serves to assure that the open arcuate shaped section (AS1R) will spread open when said mounting clip (MCR) is placed onto a "Half-Round" gutter system.
Turning now to FIG. 6, in the case where a vinyl gutter system is present said mounting clip (MCV) is shown as secured thereto by causing a projecting lip (PLV) thereof to be present between the downward and to the left (A) and the upward and to the right (C) lengths of construction material which form said hemmed section. Said projecting lip (PLV) being projected upward and to the right, as viewed in right side elevation, and being merged into a common point (CP), by a downward and typically to the left projecting length of construction material (DL1V). From said common point (CP) there are projected a right (RL) and a left leg (LL). Said right leg (RL) comprises a downward and to the right length of construction material (DR1V), said downward and to the right length of construction material (DR1V) being merged into an arcuate shaped section of construction material (ASLV) which opens generally to the left, said arcuate shaped section of construction material (ASLV) which opens to the left being merged into an arcuate shaped section of construction material (ASRV) which opens generally to the right. Said left leg (LL) comprises a downward and to the left projecting length of construction material (DL1V'). At the end of at least said left leg there is present a length of construction material which projects generally downward and outward from said common point (DO1V). Said mounting clip (MCV) elements beyond said projecting lip (PLV) serve to facilitate interfacing to the forward upper aspect of a "Vinyl" gutter system in use. In particular, the shown generally downward and outward to the left length of construction material from said common point (DO1V), and the lower portion of arcuate shaped length of construction material (ASRV) which projects to the right, provide a shape which assures that said elements will spread apart when said mounting clip (MCR) is placed onto a "Vinyl" gutter system. (It is noted that the arcuate shaped section of construction material (ASLV) which opens generally to the left, and said arcuate shaped section of construction material (ASRV) which opens generally to the right, as shown, can involve very tight bends rather than gradual arcuate shapes).
It is to be understood that a mounting clip is secured to said hemmed section comprised of a first downward and to the left (A) projecting length of construction material which is merged into a first upward and to the right projecting length of construction material (C) by way of an essentially one-hundred-eighty degree bend (B), by causing an upward and to the right projecting lip (PL) thereof to be present between the downward and to the left (A) and the upward and to the right (C) lengths of construction material which form said hemmed section (HS).
Turning now to FIGS. 7a and 7b, it will be appreciated that, as viewed from above, a mounting clip projecting lip (PL) can be rotated through some angle, (in the plane of the paper as shown), without being removed from said hemmed section (HS), said rotation serving to facilitate installation of said gutter protection system to gutter systems which present with non-uniform shaped forward upper aspects. In conjunction with the available third-dimensional rotation motion described with respect to FIG. 2b, (see infra herein), it should be appreciate that said projecting lip (PLK) can rotate in said hemmed section (HS) to limited degrees in three-dimensions. This provides a user great mounting facilitating capability and is considered a very important aspect of the present invention.
It is noted that while drawings do not specifically show half-round and vinyl gutter systems, the shape of present invention mounting clip mating forward upper aspects of such gutter systems can be appreciated by understanding that the shape of the mounting clips are such so as to "snap" thereover and thereonto in use.
It is generally noted that relatively tight bends can be approximated by gradual arcuate shapes, (and vice versa), which perform the same function, in all the structure described infra herein, particularly as regards the shape of the various mounting clips. The Claims should be read as sufficiently broad to include such functionally equivalent interpretations.
Having hereby disclosed the subject matter of the present invention, it should be obvious that many modifications, substitutions, and variations thereof are possible in light thereof. It is therefore to be understood that the present invention can be practiced other than as specifically described, and should be limited in breadth and scope only by the Claims. | Disclosed is a gutter protection system which serves to protect gutter systems that collect rain water at the lower edges of sloping building roofs in use, while preventing the accumulation of debris therein. In particular, mounting clips in combination with hemmed gutter protection system design, which facilitate installation of gutter protection systems, are described. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Patent Application No. PCT/CN2011/072943, filed Apr. 18, 2011, which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention relate to communications technologies, and in particular, to a method and device for determining power consumption of a communication site.
BACKGROUND OF THE INVENTION
[0003] In a mobile communication network, accompanying with an increase of subscribers and a fast increase of data services, traffic volume of communication grows quickly and mobile network power consumption is in a growing tendency. In order to realize network energy saving and emission reduction, it is necessary to monitor power consumption of a communication site, so as to find a power consumption state of the base station and make an energy saving policy.
[0004] A configuration situation of a typical communication site is as follows: A base station in a communication site includes a baseband unit module and a base station carrier module, and further includes a fan, a transmission device, and so on. The communication site is further configured with auxiliary devices such as a communication power supply, a solar energy power supply, a wind energy power supply, an equipment room power supply, and an equipment room air-conditioner. The auxiliary devices are connected to an auxiliary monitoring interface module, where the auxiliary monitoring interface module is configured to report power consumption of the auxiliary devices. The auxiliary monitoring interface module reports the power consumption of the auxiliary device to a power consumption reporting module of the base station. The power consumption reporting module of the base station sends power consumption of the base station and the power consumption of the auxiliary device to an Operating and supporting system (OSS).
[0005] However, part of the auxiliary devices of the communication site have a power consumption monitoring capability and part of the auxiliary devices do not have a power consumption reporting capability, therefore, part of the auxiliary devices cannot realize power consumption reporting through the power consumption reporting module. In the same way, the baseband unit module and the base station carrier module in the base station may realize power consumption reporting through the power consumption reporting module, but the transmission device and the fan cannot report power consumption. Therefore, power consumption reported to the OSS by the base station cannot completely reflect power consumption of the communication site.
SUMMARY OF THE INVENTION
[0006] Embodiments of the present invention provide a method and device for determining power consumption of a communication site, so as to solve a defect that in the prior art, power consumption of a communication site, which is obtained by an OSS, is not complete.
[0007] An embodiment of the present invention provides a method for determining power consumption of a communication site, where the method includes:
[0008] receiving power consumption reported by the communication site;
[0009] determining power consumption of virtual devices in the communication site according to power of the virtual devices in the communication site and/or traffic volume of the communication site, where the virtual devices include one or more devices which are not capable of monitoring power consumption monitoring and one or more devices which are not capable of reporting power consumption in the communication site; and the traffic volume of the communication site is traffic volume of the communication site at a time point when the power consumption is reported; and
[0010] determining power consumption of the communication site according to the power consumption reported by the communication site and the power consumption of the virtual devices in the communication site.
[0011] An embodiment of the present invention provides a device for determining power consumption of a communication site, where the method includes:
[0012] a power consumption receiving module, configured to receive power consumption reported by the communication site;
[0013] a virtual device power consumption calculation module, configured to determine power consumption of virtual devices in the communication site according to power of the virtual devices in the communication site and/or traffic volume of the communication site, where the virtual devices include a device without a power consumption monitoring capability and a device without a power consumption reporting capability in the communication site, and the traffic volume of the communication site is traffic volume of the communication site at a time point when the power consumption is reported; and
[0014] a power consumption calculation module, configured to determine power consumption of the communication site according to the power consumption reported by the communication site and the power consumption of the virtual devices in the communication site.
[0015] In the embodiments of the present invention, the device without a power consumption monitoring capability and the device without a power consumption reporting capability in the communication site are defined as virtual devices. After receiving the power consumption reported by the communication site, an OSS power consumption platform obtains the traffic volume of the communication site at the time point when the power consumption is reported and determines power consumption of each virtual device respectively according to the traffic volume of the communication site and power of each virtual device. After aggregating the reported power consumption with power consumption of all virtual devices, the OSS power consumption platform obtains total power consumption of the communication site. Therefore, in the embodiments of the present invention, the OSS power consumption platform implements statistics of the total power consumption of the communication site, so that an appropriate energy saving policy may be made for the communication site.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the accompanying drawings required for describing the embodiments or the prior art are introduced briefly in the following. Apparently, the accompanying drawings in the following description are only some embodiments of the present invention, and persons of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.
[0017] FIG. 1 is a flow chart of a method for determining power consumption of a communication site according to an embodiment of the present invention;
[0018] FIG. 2 is a flow chart of another method for determining power consumption of a communication site according to an embodiment of the present invention;
[0019] FIG. 3 is an application scenario diagram of another method for determining power consumption of a communication site according to an embodiment of the present invention;
[0020] FIG. 4 is a schematic structural diagram of a device for determining power consumption of a communication site according to an embodiment of the present invention; and
[0021] FIG. 5 is a schematic structural diagram of a virtual device power consumption calculation module in FIG. 4 .
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the embodiments in the following description are merely a part rather than all of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0023] FIG. 1 is a flow chart of a method for determining power consumption of a communication site according to an embodiment of the present invention. As shown in FIG. 1 , this embodiment includes:
[0024] Step 11 : An OSS power consumption platform receives power consumption reported by a communication site.
[0025] The communication site reports power consumption of the communication site to the OSS power consumption platform, and the power consumption reported by the communication site includes power consumption of one or more devices which are capable of monitoring and reporting their power consumption in the communication site.
[0026] Step 12 : The OSS power consumption platform determines power consumption of one or more virtual devices in the communication site according to power of the virtual devices and/or traffic volume of the communication site.
[0027] In the communication site, some devices is capable of reporting their power consumption, but not capable of monitoring their power consumption. For example, a transmission device and a power amplification device that may report information to a base station in the communication site, they are capable of reporting power consumption but they are not capable of monitoring power consumption. Therefore, power consumption reported to the OSS by the base station does not include power consumption of these devices. Some devices are capable of monitoring power consumption but they are not capable of reporting power consumption. For example, an equipment room power supply in the communication site is capable of displaying its power consumption on a local monitor screen but is not capable of reporting its power consumption to the OSS. In the communication site, some devices are not capable of monitoring power consumption and reporting power consumption, such as a fan and an equipment room air-conditioner. In this embodiment of the present invention, the one or more virtual devices include: one or more devices which are not capable of monitoring power consumption and one or more devices which are not capable of reporting power consumption reporting in the communication site, such as a transmission device, a power amplification device, a fan, an equipment room power supply, and an equipment room air-conditioner, etc.
[0028] The traffic volume of the communication site is traffic volume of the communication site at a time point when the power consumption is reported. The traffic volume of the communication site may include at least one of the following: a circuit service volume, temperature, and radio output power of the communication site.
[0029] Power consumption of each virtual device may be related to power of the virtual device and the traffic volume of the communication site. The power of a virtual device is power after the virtual device is powered on and before service processing is performed, and is related to configuration and type of the virtual device. For example, a first virtual device is a device with fixed power consumption, such as a transmission device, etc.; and the first virtual device's power consumption is fixed and unchangeable given the same configuration and type. The power consumption of the first virtual device is related to the configuration and type rather than the traffic volume of the communication site. After being configured, no matter whether data being received or sent, the transmission device is in a working state and its power consumption is power consumption in the case of current configuration. If the virtual device is a device with fixed power consumption, the OSS power consumption platform determines power consumption of the virtual device in the communication site according to power of the virtual device in the communication site.
[0030] Some virtual devices are devices with changeable power consumption. These virtual devices' power consumption is not just related to the configuration and type, but also related to the traffic volume of the communication site. A second virtual device is a device with a first order linear relationship between its power consumption and the traffic volume of the communication site, such as a power amplification device. The second virtual device's power consumption is related to the traffic volume of the communication site in a first order linear relationship given the same configuration and type. A third virtual device is a device with a second order linear relationship between its power consumption and the traffic volume of the communication site, such as a fan. The third virtual device's power consumption is related to the traffic volume of the communication site in a second order linear relationship given the same configuration and type. Some other devices are fourth virtual devices such as an equipment room power supply. For the fourth virtual devices, in the case that configuration and types are the same, power consumption needs to be obtained by searching a traffic volume and power consumption mapping table. In the communication site, for persons skilled in the art, a device with another relationship between power consumption and the traffic volume of the communication site may also exist, which is not repeated herein.
[0031] If the virtual device is a device with changeable power consumption, the OSS power consumption platform determines power consumption of the virtual device in the communication site according to power of the virtual device in the communication site and the traffic volume of the communication site.
[0032] After the OSS power consumption platform determines power consumption of each virtual device in the communication site according to the power of the virtual device and the traffic volume of the communication site, total power consumption of all virtual devices may also be calculated. In this embodiment, according to the power consumption of the first virtual devices, the power consumption of the second virtual devices, the power consumption of the third virtual devices, and the power consumption of the fourth virtual devices in the communication site, the OSS power consumption platform obtains power consumption of all virtual devices in the communication site.
[0033] Step 13 : The OSS power consumption platform determines power consumption of the communication site according to the reported power consumption and the power consumption of the virtual devices.
[0034] In this embodiment of the present invention, the devices without power consumption monitoring capability and the devices without power consumption reporting capability in the communication site are defined as virtual devices. After receiving the power consumption reported by the communication site, the OSS power consumption platform obtains the traffic volume of the communication site at the time point when the power consumption is reported, determines the power consumption of the virtual devices according to the traffic volume of the communication site and the power of the virtual devices, and obtains the power consumption of the communication site according to the reported power consumption and the power consumption of the virtual devices. Therefore, in this embodiment of the present invention, the OSS power consumption platform implements statistics of the power consumption of the communication site, so that an appropriate energy saving policy may be made for the communication site.
[0035] FIG. 2 is a flow chart of another method for determining power consumption of a communication site according to an embodiment of the present invention; and FIG. 3 is an application scenario diagram of another method for determining power consumption of a communication site according to an embodiment of the present invention.
[0036] As shown in FIG. 2 , this embodiment includes:
[0037] Step 21 : An OSS power consumption platform receives power consumption reported by a communication site.
[0038] A base station in the communication site reports power consumption of the communication site and traffic volume of the communication site to the OSS power consumption platform through a management channel of a base station controller. The power consumption reported by the communication site includes: power consumption of devices which are capable of monitoring power consumption and reporting power consumption in the communication site. In addition, the base station may also periodically report the traffic volume of the communication site together with the power consumption of the communication site to the OSS. After receiving the traffic volume reported by the communication site, the OSS platform stores the traffic volume for query and analysis.
[0039] In the communication site, some devices are not capable of monitoring power consumption, some devices are capable of monitoring power consumption but not capable of reporting power consumption, or some devices are not capable of reporting power consumption and monitoring power consumption. In FIG. 3 , virtual devices include: a transmission device, a power amplification device, a fan, an equipment room power supply, an equipment room air-conditioner, and so on. In FIG. 3 , devices which are capable of reporting power consumption and monitoring power consumption include: a baseband unit module (BBU), a base station carrier module (TRU), a communication power supply, a solar energy power supply, a wind energy power supply, and so on. The communication power supply, the solar energy power supply, and the wind energy power supply may report monitored power consumption to the base station, and the base station reports the monitored power consumption to the OSS power consumption platform.
[0040] In this embodiment, power consumption of the virtual devices in the communication site is determined through the following steps.
[0041] Step 22 : The OSS power consumption platform determines power consumption of the virtual devices in the communication site according to power of the virtual devices and/or traffic volume of the communication site.
[0042] The traffic volume of the communication site is traffic volume of the communication site at a time point when the power consumption is reported.
[0043] In this embodiment, the OSS power consumption platform includes a device list of the communication site. In order to make statistics on power consumption of each virtual device, the OSS power consumption platform, according to a feature of each device, defines devices which are not capable of reporting power consumption and devices which are not capable of monitoring power consumption in the device list as virtual devices. By analyzing power consumption of the virtual devices and the traffic volume of the communication site, in this embodiment, the virtual devices are classified into four main categories and a corresponding relationship between power consumption of a virtual device and the traffic volume is established for each virtual device.
[0044] Specifically, a virtual device power consumption function table, as shown in Table 1, may be established, where P0 is power of a virtual device in the case of certain configuration and a certain type. In Table 1, a virtual device category may correspond to multiple virtual devices; and virtual devices belonging to the same category have the same corresponding relationship between their power consumption and the traffic volume. In this embodiment, one or more first virtual devices are devices with fixed power consumption. The power consumption of the one or more first virtual devices is fixed and unchangeable given the same configuration and type. A second virtual device, a third virtual device, and a fourth virtual device are devices with changeable power consumption. Their power consumption is not just related to their configurations and types, but also related to traffic volume of a communication site given the same configurations and types. Specifically, a first order linear relationship P=P0+k1*ta is set between power consumption of the second virtual device, such as a power amplification device, and the traffic volume of the communication site. A second order linear relationship P=P0+k1×ta+k2×ta 2 is set between power consumption of the third virtual device, such as a fan, and the traffic volume of the communication site. Some other devices are set as fourth virtual devices, such as an equipment room power supply. For the fourth virtual devices, in the case that configuration and types are the same, power consumption needs to be obtained by searching a traffic volume and power consumption mapping table. In the communication site, for persons skilled in the art, a device with another relationship between power consumption and the traffic volume of the communication site may also exist, which is not repeated herein.
[0000]
TABLE 1
Virtual device power consumption function table
Virtual Device
Category
Virtual Device
Power Consumption Function
First virtual device
Transmission
P = P0
device, . . .
Second virtual device
Power
P = P0 + k1 × ta
amplification
device, . . .
Third virtual device
Fan, . . .
P = P0 + k1 × ta + k2 × ta 2
Fourth virtual device
Equipment room
Search the traffic volume
power supply . . .
and power consumption
mapping table
[0045] In this embodiment, a relationship between the traffic volume and the power consumption of the fourth virtual device (such as an equipment room power supply or an equipment room air-conditioner) may be obtained through practical measurement and analysis, as shown in Table 2.
[0000]
TABLE 2
Traffic volume and power consumption mapping table
Traffic volume
Power Consumption
ta 1
p1
ta 2
p2
ta 3
P3
. . .
. . .
ta n
Pn
[0046] For each virtual device in the device list of the communication site, the OSS power consumption platform determines power consumption of a virtual device according to power of the virtual device and/or the traffic volume of the communication site and with reference to a virtual device category to which each virtual device belongs. In this embodiment, if the virtual device is a first virtual device with fixed power consumption, the OSS power consumption platform determines power consumption of the virtual device in the communication site according to power of the virtual device in the communication site. If the virtual device is a device with changeable power consumption, the OSS power consumption platform determines power consumption of the virtual device in the communication site according to power of the virtual device in the communication site and the traffic volume of the communication site. Specifically, the OSS power consumption platform determines power consumption of the second virtual device in the communication site according to a first order linear relationship between power consumption of the second virtual device and the traffic volume of the communication site. The OSS power consumption platform determines the power consumption of the third virtual device in the communication site according to a second order linear relationship between power consumption of the third virtual device and the traffic volume of the communication site. The OSS power consumption platform determines power consumption of the fourth virtual device in the communication site according to the traffic volume and power consumption mapping table.
[0047] Step 23 : The OSS power consumption platform obtains total power consumption of all virtual devices according to power consumption of each virtual device.
[0048] In this embodiment, the OSS power consumption platform may obtain power consumption of all virtual devices in the communication site after aggregating the power consumption of the first virtual devices, the power consumption of the second virtual devices, the power consumption of the third virtual devices, and the power consumption of the fourth virtual devices in the communication site.
[0049] Step 24 : The OSS power consumption platform calculates power consumption of the communication site according to the power consumption reported by the communication site and the total power consumption of all virtual devices.
[0050] After receiving the power consumption reported by the communication site, the OSS power consumption platform obtains the traffic volume of the communication site at the time point when the power consumption is reported, and determines power consumption of each virtual device in the device list of the communication site according to the power of the virtual device and/or the traffic volume of the communication site and with reference to the virtual device category to which each virtual device belongs. The OSS power consumption platform obtains the power consumption of the communication site according to the reported power consumption and the power consumption of all virtual devices. Therefore, in this embodiment of the present invention, the OSS power consumption platform implements statistics of the power consumption of the communication site, so that an appropriate energy saving policy may be made for the communication site.
[0051] FIG. 4 is a schematic structural diagram of a device for determining power consumption of a communication site according to an embodiment of the present invention. As shown in FIG. 4 , this embodiment includes: a power consumption receiving module 41 , a virtual device power consumption calculation module 42 , and a power consumption calculation module 43 .
[0052] The power consumption receiving module 41 is configured to receive power consumption reported by a communication site.
[0053] The power consumption reported by the communication site is power consumption of a device with both a power consumption monitoring capability and a power consumption reporting capability.
[0054] The virtual device power consumption calculation module 42 is configured to determine power consumption of virtual devices in the communication site according to power of the virtual devices and/or traffic volume of the communication site.
[0055] The virtual devices include: a device without a power consumption monitoring capability and a device without a power consumption reporting capability in the communication site, such as a transmission device, a power amplification device, a fan, an equipment room power supply, and an equipment room power supply.
[0056] The traffic volume of the communication site is traffic volume of the communication site at a time point when the power consumption is reported. Power consumption of each virtual device may be related to power of the virtual device and/or the traffic volume of the communication site. In this embodiment, it is set that a first virtual device is a device with fixed power consumption, and a second virtual device, a third virtual device, and a fourth virtual device are devices with changeable power consumption. In the case that configuration and types are the same, a first order linear relationship P=P0+k1*ta is set between power consumption of the second virtual device and the traffic volume of the communication site, such as a power amplification device. A second order linear relationship P=P0+k1×ta+k2×ta 2 is set between power consumption of the third virtual device and the traffic volume of the communication site, such as a fan. Some other devices are set as fourth virtual devices such as an equipment room power supply. For the fourth virtual devices, in the case that configuration and types are the same, power consumption needs to be obtained by searching a traffic volume and power consumption mapping table. In the communication site, for persons skilled in the art, a device with another relationship between power consumption and the traffic volume of the communication site may also exist, which is not repeated herein.
[0057] The power consumption calculation module 43 is configured to determine power consumption of the communication site according to the power consumption received by the power consumption receiving module 41 and the power consumption of the virtual devices in the communication site, where the power consumption of the virtual devices in the communication site is determined by the virtual device power consumption calculation module 42 .
[0058] In this embodiment of the present invention, the device without a power consumption monitoring capability and the device without a power consumption reporting capability in the communication site are defined as virtual devices. After the power consumption receiving module 41 receives the power consumption reported by the communication site, the virtual device power consumption calculation module 42 obtains the traffic volume of the communication site at the time point when the power consumption is reported, and determines power consumption of each virtual device according to the traffic volume of the communication site and power of each virtual device. The power consumption calculation module 43 obtains the power consumption of the communication site according to the reported power consumption and the power consumption of the virtual devices. Therefore, in this embodiment of the present invention, the OSS power consumption platform implements statistics of the power consumption of the communication site, so that an appropriate energy saving policy may be made for the communication site.
[0059] FIG. 5 is a schematic structural diagram of a virtual device power consumption calculation module in FIG. 4 . As shown in FIG. 5 , a virtual device power consumption calculation module 42 includes: a first calculation unit 421 , a second calculation unit 422 , a third calculation unit 423 , a fourth calculation unit 424 , and a fifth calculation unit 425 .
[0060] The first calculation unit 421 is configured to determine power consumption of a first virtual device according to power of the first virtual device, where the first virtual device is a device with fixed power consumption in a communication site.
[0061] The second calculation unit 422 is configured to determine power consumption of a second virtual device according to power of the second virtual device and traffic volume of the communication site, where there is a first order linear relationship between the power consumption of the second virtual device and the traffic volume of the communication site.
[0062] The third calculation unit 423 is configured to determine power consumption of a third virtual device according to power of the third virtual device and the traffic volume of the communication site, where there is a second order linear relationship between the power consumption of the third virtual device and the traffic volume of the communication site.
[0063] The fourth calculation unit 424 is configured to determine, according to the traffic volume of the communication site, power consumption of a fourth virtual device by searching a traffic volume and power consumption mapping table.
[0064] The fifth calculation unit 425 is configured to obtain power consumption of all virtual devices in the communication site according to the power consumption of the first virtual device, the power consumption of the second virtual device, the power consumption of the third virtual device, and the power consumption of the fourth virtual device.
[0065] In this embodiment of the present invention, each unit determines power consumption of each virtual device in a device list of the communication site according to the power of the virtual device and the traffic volume of the communication site. According to the reported power consumption and the power consumption of all virtual devices, power consumption of the communication site is obtained. Therefore, in this embodiment of the present invention, statistics of the power consumption of the communication site is implemented, so that an appropriate energy saving policy may be made for the communication site.
[0066] Those of ordinary skill in the art may understand that all or a part of the steps of the foregoing method embodiments may be implemented by a program instructing relevant hardware. The program may be stored in a computer readable storage medium. When the program runs, the steps of the foregoing method embodiments are performed. The storage medium may include any medium that is capable of storing program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.
[0067] Finally, it should be noted that the foregoing embodiments are merely used for describing the technical solutions of the present invention, but are not intended to limit the present invention. It should be understood by persons of ordinary skill in the art that although the present invention has been described in detail with reference to the foregoing embodiments, modifications may still be made to the technical solutions described in the foregoing embodiments, or equivalent replacements may be made to some technical features in the technical solutions; however, these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions in the embodiments of the present invention. | In a mobile communication network, technologies are provided for determining power consumption of a communication site. An OSS system receives power consumption information of one or more devices and traffic volume information from a communication site. Then, the OSS determines power consumption of one or more virtue devices of the communication site, which are listed on a pre-configured device list according to power of the virtue devices, traffic volume information of the communication site, or both, wherein the a virtue device is not capable of monitoring power consumption, reporting power consumption, or both. Then the OSS determines power consumption of the communication site according to the power consumption information of the one or more devices received from the communication site and the power consumption of the virtual device in the communication site. | 8 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to opening means in a pillow package bag provided with easy unsealing means.
[0003] 2. Description of the Related Art
[0004] In a pillow package bag, both sides of one film are brought toward the center and back fin sealing is performed on the both sides to form a cylindrical shape, and a bottom and mouth are sealed so as to cross this heat-sealed portion after the formation into the cylindrical shape.
[0005] When such a pillow package bag is unsealed by tearing the bag from a side of the bag, the tearing stops at the back-sealing sealed portion, as a result of which the bag cannot be further torn. Therefore, it is necessary to use a pair of scissors to unseal the bag.
[0006] In order to make it possible to unseal a bag without using scissors, the applicant for the invention proposed a pillow package bag provided with easy unsealing means discussed in Japanese Patent No. 4199024 (Patent Document 1).
[0007] The aforementioned publicly known bag is currently widely used and popular, but has one problem.
[0008] The aforementioned publicly known bag has made unsealing of a bag easy, but when opening a torn mouth of the unsealed bag, edges 5 a and 6 a of torn front and back films 5 and 6 of a bag 1 become aligned, as shown in FIG. 7 . Therefore, even if a person tries to open the mouth of the bag by pinching the edges 5 a and 6 a with his/her finger tips, he/she cannot pinch the edges 5 a and 6 a open.
[0009] In particular, when the films are highly rigid or a zipper 11 is inserted in the unsealing mouth, the edges 5 a and 6 a essentially contact each other.
[0010] Therefore, there are many cases in which people having disabled finger tips, elderly people and children have difficulties opening a bag, and hence, there is a demand for a proposal that solves this problem. In FIG. 7 , reference numeral 3 denotes a back sealing seal.
SUMMARY OF THE INVENTION
[0011] The present invention is made in view of the above described problem, and its object is to provide opening means that allows a bag to be easily opened after tearing an unsealing mouth even by people having disabled finger tips, elderly people and children, in a pillow package bag according to the Patent Document 1.
[0012] According to the present invention, when a bag is torn and unsealed, pinching tabs are automatically formed at a back sealing portion of the torn edges of the bag, which makes it possible to easily open the bag by pinching the tabs.
[0013] To this end, according to a first form of the present invention, there is provided opening means in a pillow package bag provided with easy unsealing means, in which a fin sealing seal is positioned at a center of a back surface of the bag, the easy unsealing means is provided along an end of the fin sealing seal, the fin sealing seal is folded down to one side and is heat-sealed to an outer-side film of the bag, a heat-seal portion is formed at a side end of the bag in a direction in which the fin sealing seal is folded down, and a V-shaped or an I-shaped notch extending in a direction of the fin sealing seal is formed in the heat-seal portion. Here, the easy unsealing means includes a slit having a rising gradient extending toward an unsealing mouth from the end of the fin sealing seal to a portion situated partway into the fin sealing seal, and when tearing of the bag is started horizontally in a straight line from the V-shaped or I-shaped notch toward the fin sealing seal, the tear enters the slit from the end of the fin sealing seal, extends obliquely in a rising direction by the slit, reaches a base of the fin sealing seal, then, extends horizontally in a straight line again, and reaches another side end of the bag, to thereby unseal the bag entirely, as a result of which an opening tab is formed at the fin sealing seal at the torn mouth of the fin sealing seal.
[0014] According to a second form of the present invention, in the opening means in the first form, a plurality of the slits are formed.
[0015] According to a third form of the present invention, in the opening means in the first form, an angle of the gradient of the slit is set arbitrarily in a range of from 12 degrees to 45 degrees.
[0016] According to a fourth form of the present invention, in the opening means in the first form, the slit is formed to bend horizontally from an apex of the gradient.
[0017] According to a fifth form of the present invention, in the opening means in the first form, an entrance of the slit is provided with a V-shaped inlet.
[0018] According to the present invention, as mentioned above, tabs are formed at the torn edges at the unsealed mouth, and hence the bag can be easily opened by pinching the tabs.
[0019] Therefore, the present invention is effective for, in particular, people having disabled finger tips, elderly people and children.
[0020] 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 objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In the drawings:
[0022] FIG. 1 is a perspective view illustrating a pillow package bag to which the present invention is applied;
[0023] FIG. 2 is a perspective view illustrating a fin sealing portion provided with the easy unsealing means;
[0024] FIG. 3 is a perspective view illustrating a state in which the bag is being unsealed;
[0025] FIG. 4 is a perspective view illustrating a state in which the bag is being opened by pinching tabs;
[0026] FIG. 5 is a view illustrating a first embodiment in which auxiliary slits are formed at upper ends of slits;
[0027] FIG. 6 illustrates another embodiment in which an inlet is formed at an entrance of the slit; and
[0028] FIG. 7 illustrates a related pillow package bag provided with easy unsealing means.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Referring to the drawings in particular, the present invention is effective, in particular, when a zipper is inserted in an unsealing mouth. However, it is also applicable to bags in which this zipper is not inserted.
[0030] The present invention is also applicable to both gusset bags and non-gusset bags.
[0031] The materials of the bag include plastic film composites or plastic films that are composite with aluminum foil films.
[0032] Embodiments of inventions of respective first to fifth forms will be described below in detail with reference to FIGS. 1 to 6 .
[0033] In each figure, reference numeral 1 denotes a pillow package bag, reference numeral 2 denotes a mouth seal of the pillow package bag 1 , and reference numeral 3 denotes a fin sealing seal that is positioned at the center of a back surface 6 . The fin sealing seal 3 is folded down at the back surface 6 of the bag 1 , and is heat-sealed to the front surface of the back film 6 .
[0034] Reference numerals 4 denote slits that are formed by forming cuts in the fin sealing seal 3 with rising gradients from its end 3 a . Ends 4 b of the slits 4 stop before reaching a base 3 b of the fin sealing seal 3 .
[0035] Reference numeral 8 denotes a seal portion formed by partly heat-sealing a front film 5 and a back film 6 at the position opposing the slits 4 in a side end 1 a of the bag 1 provided in the direction in which the fin sealing seal 3 is folded down. A V-shaped or an I-shaped notch 9 extending toward the slits 4 is formed in the seal portion 8 .
[0036] As long as an area including the slits 4 or areas above and below the slits 4 are heat-sealed to the back film 6 of the bag 1 , there is no problem in unsealing (tearing) the fin sealing seal 3 . However, the entire fin sealing seal 3 may be heat-sealed to the back film 6 .
[0037] Reference numeral 11 denotes a zipper inserted in an unsealing mouth 7 .
[0038] Unsealing of the bag 1 having the above-described structure will now be explained. As shown in FIG. 3 , when the bag 1 is torn from the V-shaped or I-shaped notch 9 , the front film 5 and the back film 6 are torn horizontally along a direction a indicated by a dotted line. Eventually, the tear reaches the end 3 a of the fin sealing seal 3 . Then, the tear enters an entrance 4 a of one of the slits 4 from the end 3 a , and extends in a rising direction along the inclination of the slit 4 . Then, when the slit 4 is torn at an upper end 4 b of the slit 4 , the tear extends horizontally again at the fin sealing seal 3 . Then, the tear extends into the front film 5 and the back film 6 of the bag 1 from the base 3 b , and extends horizontally up to a side end 1 b of the bag 1 . As a result, the bag 1 is fully unsealed.
[0039] FIG. 4 is an enlarged view of the torn mouth 7 when the bag 1 is fully unsealed in this way. Triangular tabs 10 are formed between the inclined portion of the slit 4 and the portion where the bag 1 is torn horizontally from the upper end 4 b of the slit 4 .
[0040] Thus, edges 5 a and 6 a at the torn mouth become easier to pinch at the tabs 10 . Consequently, as shown in FIG. 4 , the bag 1 can be easily opened by pinching the tabs 10 with the finger tips.
[0041] Since the tabs 10 become small when a slit- 4 angle is small, the slit- 4 angle is at least equal to or greater than 12 degrees. Tearing strength becomes high when the slit- 4 angle exceeds 45 degrees, and hence it is practically desirable that the slit- 4 angle be approximately 35 degrees. This feature of a preferred angle corresponds to the aforementioned third form.
[0042] When auxiliary slits 4 c are formed by horizontally bending the upper ends 4 b of the slits 4 , the front film 5 and the back film 6 that are torn along the slits 4 become easier to tear because a tearing direction is changed to the horizontal direction (transverse direction) by the auxiliary slits 4 c . This corresponds to the aforementioned fourth form.
[0043] In the above-described structure and operation, the number of slits 4 is not limited, but three to four slits 4 are enough.
[0044] If, as shown in FIG. 6 , a V-shaped inlet 4 d is formed at the entrance 4 a of the slit 4 , the tear easily enters the slit 4 , and the number of the slits 4 may be reduced.
[0045] The tabs 10 are certainly convenient, if their existence is indicated by words, such as “pinch here to open”, or by coloring them.
[0046] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. | In a pillow package bag provided with an easy unsealing device, a slit having a rising gradient is provided as the easy unsealing device formed at a back sealing seal. Triangular tabs are formed at the back sealing seal of edges of a torn bag. As a result, it is easy for people having disabled finger tips, elderly people and children to open the unsealed bag by pinching the tabs. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. patent application Ser. No. 13/752,003, filed Jan. 28, 2013, now U.S. Pat. No. 9,133,525, issued Sep. 15, 2015, which claims benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Application 61/716,123, filed Oct. 19, 2012 and to U.S. Provisional Application 61/591,111, filed Jan. 26, 2012, which are each expressly incorporated herein by reference.
[0002] The subject matter disclosed in U.S. application Ser. Nos. 61/186,610; 61/358,282; 61/476,110; 61/476,545; 12/797,286; 13/168,367; 61/591,111; and PCT/US2010/038160 is hereby expressly incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] DNA can be amplified from human red blood cell samples by primers designed from DNA sequences encoding a bacterial major surface protein and 16 s ribosomal RNA (16s rRNA). Primer pairs based on DNA sequences for the major surface protein 2 (MSP2) of Erhlichia/Anaplasma can amplify DNA homologous to DNA from human chromosomes 1 and 7 from red blood cell samples. Primers based on DNA sequences encoding 16s rRNA from Anaplasma species can amplify DNA from human red blood cells, but not from nucleated white blood cells. The amplified DNA is contained in samples of red blood cells from HIV infected individuals as well as from some healthy individuals of Caucasian or African origin and represents a risk factor for HIV infection. These primers can be employed in methods for assessing risk of HIV infection by amplifying DNA from red blood cell samples.
[0005] 2. Description of the Related Art
[0006] Chronic HIV infection causes strong immune depression (AIDS) in most patients leading to lethal opportunistic infections or cancers. Specific inhibitors of HIV multiplication are currently used for treating HIV infected patients before they reach the full-blown stage of AIDS. Such inhibitors act mostly on the reverse transcriptase and protease of HIV to efficiently suppress virus multiplication and reduce virus load to a low level of less than 40 viral RNA copies per ml of blood. Treatment results in a partial recovery of the patient's immune system as evidenced by an increase of CD4 lymphocytes and reduction of or lessened severity of opportunistic infections. However, this treatment has to be given without interruption in order to prevent rebound of virus multiplication and a subsequent reduction in the numbers of CD4 lymphocytes. Rebound of viral infection is evidence of a reservoir of HIV in infected patients that is not accessible to antiviral treatment and the existence of this reservoir is generally acknowledged. In addition to a reservoir of HIV in infected patients, such patients often carry other microorganisms that are associated with HIV infection or that cause opportunistic infections.
[0007] Microorganisms associated with HIV infection that are detectable in human red blood cells, but not in human leukocytes or other kinds of nucleated human cells have not been previously characterized. The identification and characterization of microorganisms associated with HIV infection is of interest for purposes of assessing risk of HIV infection or determining the status of an HIV infected patient, for assessing risk or status of opportunistic infections, and to evaluate modes of treatment for HIV infected subjects.
SUMMARY OF THE INVENTION
[0008] The primers designed and discovered by the inventor provide ways to pursue these objectives. Three kinds of primers have been developed and studied by the inventor.
[0009] The first kind of primer was designed based on the gene encoding the outer surface protein 2 of Ehrlichia/Anaplasma a genus of rickettsiales, which are known endosymbionts of other cells. These primers amplified DNA homologous to segments of DNA from human chromosomes 1 and 7. These primers are described in Appendix 2.
[0010] This first kind of primers were initially designed to detect DNA encoding the major surface protein 2 (MSP2) of Erhlichia/Anaplasma species. However, neither of the two pairs of primers described by Appendix 2 (Primer Pairs 1 and 2) detected at various annealing temperatures any related microorganism in the biological samples investigated.
[0011] Surprisingly, it was discovered that this first kind of primer amplified DNA from human red blood cell samples that was highly homologous to DNA sequences on segments of human chromosomes 1 and 7. Primer Pairs 1 and 2 amplified DNA by the polymerase chain reaction (“PCR”) that was 100% homologous with human sequences when the primer sequences themselves were excluded. The amplified DNA was sequenced and the sequences aligned to sequences described for human chromosome 1 (clone RP11-332J14 GI:22024579, clone RP11-410C4 GI:17985906, and Build GRCh37.p5 Primary Assembly-) and in human chromosome 7 (PAC clone RP4-728H9 GI:3980548; human Build GRCh37.p5, and alternate assembly HuRef SCAF — 1103279188381:28934993-35424761). This was not expected since the primer pairs had been designed to detect genes encoding a bacterial MSP2 gene, not human chromosomal sequences. Furthermore, the amplification of such sequences from samples of red blood cells was in itself surprising since red blood cells lack a nucleus containing chromosomes. The ability to amplify DNA homologous to human DNA from red blood cells is evidence that the target DNA amplified by these primers is present as an extranuclear or cytoplasmic element, such as a plasmid, or is contained in or bound by a microorganism that invades or is otherwise associated with red blood cells. This DNA component may be present on a plasmid or otherwise contained in or bound to a microbe associated with red blood cells. Its presence represents a risk factor for HIV infection or progression and/or opportunistic infections.
[0012] A second kind of primer was designed based on the sequences homologous to human chromosomes 1 and 7 that were amplified by the first kind of primers (MSP2 primers). This kind of primer is useful for identifying the target DNA homologous to human chromosomes 1 and 7 in a sample, such as a red blood cell sample. Such primers, including the first type of MSP2 primers, are used to detect risks of HIV infection, HIV progression, risks of opportunistic infections, disease prognosis and response to drug treatment in subjects where the presence of DNA homologous to segments human chromosomes 1 and 7 is a risk factor. This kind of primer is exemplified in Appendix 3.
[0013] A third type of primer was developed based on the genes from Anaplasma species encoding 16s rRNA. Anaplasma is a genus of rickettsiales. This type of primer was found to amplify a sequence of 700 bp of ribosomal DNA that was about 85% identical to the corresponding genetic regions of Rickettsia and about 99% identical to the corresponding genetic regions of Acinetobacter genus. Acinetobacter is a genus of gram negative bacteria within the class of gammaproteobacteria. The homology of amplified 16s rDNA with Acinetobacter DNA may be coincidental because DNA can be amplified from biological samples that pass through a 450 nM filter unlike classical Acinetobacter.
[0014] These primers identify a bacterial agent associated with red blood cells that is related to but not identical to known Rickettsia species. This bacterial agent has been identified in red blood cells of not only HIV infected patients but also in some healthy individuals of Caucasian or African origin. This third type of primer is used to detect risks of HIV infection, HIV progression, risks of opportunistic infections, disease prognosis and response to drug treatment in subjects where the presence of a target containing the amplifiable 16s rRNA or 16s rDNA is a risk factor. These primers are described in Appendix 4.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIGS. 1 and 2 show scans of gel electrophoresis lanes of different PCR amplicons.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Amplification of DNA from biological samples, including blood, plasma, and serum samples or samples obtained from cell culture can be performed using PCR or other nucleic amplification methods known in the art. These methods can be used to amplify or detect target DNA qualitatively or quantitatively to provide a “yes or no” determination of the presence of the target sequence or to quantitatively detect an amount of DNA amplified under controlled conditions.
[0017] The DNA amplified by the first and second kinds of primers is higher frequency in red blood cells obtained from patients infected with human immunodeficiency virus compared to healthy individuals. This is especially the case for patients who have undergone or are undergoing antiretroviral therapy. The quantity of DNA amplified by these primers is reduced after long-term treatment of a patient with antibiotics and the primers were found not to amplify DNA from white blood cells or from other human cell lines. DNA has also been amplified from the red blood cells of healthy African subjects not infected with HIV using these primers. These results suggest the amplified DNA is derived from an antibiotic sensitive microorganism associated with red blood cells.
[0018] Despite the apparent human origin of this DNA, the data herein show that the amplified sequences are associated with a transmissible agent and that the transmissible agent is closely associated with human immunodeficiency virus as explained below.
[0019] These sequences were easily detected in the DNA of anucleated red blood cells (RBCs) in 100% (35 out of 35 subjects) HIV-infected African and Caucasian patients and they could not be detected in the DNA of nucleated cells including in the white blood cell fraction of the same patients, nor in human DNA from cultured human cells.
[0020] These sequences were rarely detected in the red blood cell fraction of healthy African subjects and none were detected in the red blood cells of the healthy Caucasians tested.
[0021] Long term antibiotic treatment (e.g., with doxycycline or azithromycin) of HIV-positive patients for more than three months was found to decrease the intensity of the bands amplified using these primers suggesting that these bands are induced, generated or otherwise originate from an antibiotic sensitive microorganism.
[0022] Amplification of DNA from a supernatant of a short term culture of human cell line HL60 with an extract of RBC from an HIV-positive patient prepared by freeze-thawing RBC and then by removing heavy components by a low speed (10 min. at 1,500 g) centrifugation produced strong DNA bands. The intensity of these bands suggests growth and multiplication of a microorganism that contains DNA amplified by Primer Pairs 1 and 2.
[0023] To further explore this effect, new primers were designed that allow amplification of regions of human genomic DNA adjacent to or including those amplified by Primer Pairs 1 and 2. These new primers include:
[0024] primers “hChr1114179308 S” upstream of, and “hChr1114179853 AS” encompassing one end of the 237 bp amplicon related to chromosome 1 (546-bp long amplicon);
[0025] primers “hChr7/4292976 S” upstream of, and “hChr7/4294619 AS” downstream of the 213 bp amplicon related to chromosome 7 (1,643-bp long amplicon); and the primers described by Appendix 3.
[0026] These primers amplify DNA not only from the components of RBCs of HIV infected Caucasian or African patients, but also from the components of RBCs of healthy African subjects. However, these DNAs are lacking in all or most of HIV-negative Caucasian subjects. These sequences are amplified after antibiotic treatment of their carrier subjects indicating that the agent generating them is insensitive to antibiotic treatment. As in the case of the MSP2 primers-amplified sequences, these kinds of primer pairs amplify DNA present in or associated with anucleated RBC and not in white blood cells or human cell lines. It is possible that such a microorganism identified with these primers differs from the carrier of the initial short DNA sequences and will amplify or cause amplification of human genomic DNA sequences in an integrated or unintegrated manner. The primers disclosed herein permit the design of diagnostic tests and treatments aimed at reducing the risk of HIV infection in important segments of the human population in which this agent appears and can be detected by amplification of these DNA sequences.
[0027] The third kind of primers that identify a previously unknown bacterial agent that is associated with human red blood cells and related to, but not identical to, known Rickettsia species are provided. These primers are derived from the 16S ribosomal DNA sequences of an Anaplasma species and amplify a sequence of 700 bp of ribosomal DNA that is about 89% identical to the corresponding regions of the genome of Rickettsia . This sequence is about 99% identical to the corresponding regions of Acinetobacter genus DNA. Besides the primers exemplified herein, other primers that amplify the same 700 bp of ribosomal DNA or detectable fragments of this sequences may be designed based on this nucleotide sequence. These primers may amplify 20, 30, 50, 100, 200, 300, 400, 500, 600 or 700 nucleotides of this sequence. They may comprise short portions (e.g., 18-30 bp) of the 700 bp sequence and can be designed based on methods well known in the molecular biological arts. The table below depicts the various kinds of primers.
[0028] Specific embodiments of the invention include, but are not limited to those described below.
[0029] An agent that is associated with red blood cells, especially mature anucleated red blood cells, that passes through a 0.45 micron filter. This agent may be sensitive or insensitive to a particular antibiotic. Agents sensitive to azithromycin or to a cyclin antibiotic have been identified. This agent contains, induces, excises, or otherwise provides DNA that is amplified by (i) primer pairs 1 (SEQ ID NOS: 3 and 4) or 2 (SEQ ID NOS: 5 and 6), (ii) a pair of primers described by Appendix 3 (SEQ ID NOS: 7-14 or SEQ ID NOS: 15-23), (iii), the pair of primers described in Appendix 4 (SEQ ID NOS: 24 and 25); or a pair primers that amplify at least fifteen, twenty, twenty five, thirty, forty, fifty or more consecutive nucleotides of the same DNA as is amplified by the specific primers described herein.
[0030] The amplified DNA may be 80%, 85%, 90%, 95%, 99%, up to and including 100% identical or similar to human DNA, wherein sequence identity is determined by BLASTn using the default setting. Preferred parameters for determining the “nucleotide identity” when using the BLASTN program (Altschul, S. et al., Journal of Molecular Biology 215 (1990), pages 403-410) are: Expect Threshold: 10; Word size: 28; Match Score: 1; Mismatch Score: −2; Gap costs: Linear.
[0031] An agent that is associated with red blood cells, passes through a 0.45 micron filter, may be sensitive or insensitive to a particular antibiotic, can be detectable in red blood cells of an HIV patient, but not detectable in the white blood cells of said patient. Such an agent may become detectable in the red blood cells of an HIV-infected patient within the first year after HIV infection or after initiation of anti-retroviral treatment. Such an agent may appear or be associated with the red blood cells of an African subject or European subject who is HIV-negative.
[0032] The agent may be a microorganism, such as a bacterium, or a specific kind of bacterium such as Rickettsia or Rickettsia -like bacteria, Ehrlichia or Anaplasma or a component thereof. Such an agent may contain a plasmid, episome, or extra chromosomal element comprising human chromosomal DNA that is amplified by MPS2 gene primers; or that is contained in or associated with a red blood cell that contains a plasmid or extra chromosomal element comprising human chromosomal DNA that is amplified by MPS2 gene primers.
[0033] Isolated red blood cells may contain the agent as described herein as well as disrupted or lysed red blood cells, such as a supernatant produced by freezing and thawing red blood cells after removing white blood cells and then removing material that pellets by a low speed centrifugation, e.g., for 10 min. at 1,500 g. The red blood cells associated with the agent are detected by amplifying DNA from them using (i) primer pairs 1 (SEQ ID NOS: 3 and 4) or 2 (SEQ ID NOS: 5 and 6), (ii) a pair of primers described by Appendix 3 (SEQ ID NOS: 7-14 or SEQ ID NOS: 15-23), (iii), the pair of primers described in Appendix 4 (SEQ ID NOS: 24 and 25); or a pair primers that amplify at least fifteen, twenty, twenty five, thirty, forty, fifty or more consecutive nucleotides of the same DNA as is amplified by the specific primers described herein.
[0034] Another aspect of the invention is the DNA amplified from the agent or from red blood cells associated with the agent. This DNA is can be produced using the primer pairs described herein. The DNA that is present in a red blood cell may be from an infectious or replicating agent per se, from a component of an infectious organism present in the anucleated red blood cell, or from DNA that results from exposure of the red blood cell or its precursor cells to an infectious or replicating agent.
[0035] The amplified DNA from a red blood cell may comprise portions of human chromosome 1 or 7 including the sequences described in Appendix 5 or Appendix 6 or fragments of these sequences comprising 10, 20, 30, 40, 50, 100, 200 or more consecutive nucleotides of these sequences.
[0036] The DNA according to the invention may be contained or inserted into a vector, such as a plasmid or phage vector containing the isolated or purified amplified DNA. A host cell can be transformed with the isolated or purified amplified DNA from the agent or from red blood cells associated with the agent.
[0037] The invention is also directed to a method for detecting an agent as described herein comprising contacting material from anucleated red blood cells of a subject with primer Pair 1, primer Pair 2, or a pair of primers selected from the group consisting of those described in Appendix 3 under conditions suitable for amplification of DNA by said primers, and detecting said agent when amplified DNA is detected.
[0038] The primers used in this method may be selected from the group consisting of (i) primer pairs 1 (SEQ ID NOS: 3 and 4) or 2 (SEQ ID NOS: 5 and 6), or (ii) a pair of primers described by Appendix 3 (SEQ ID NOS: 7-14 or SEQ ID NOS: 15-23) or a pair primers that amplify at least fifteen, twenty, twenty five, thirty, forty, fifty or more consecutive nucleotides of the same DNA as is amplified by the specific primers described herein. Alternatively, a set of primers that amplify the same DNA fragment amplified by the two primers described above may be employed. These primers may be designed by methods known in the art and each may comprise 18-30 or more base pairs of the sequence amplified by the primers above.
[0039] A method for detecting an agent as described herein comprising: contacting under conditions suitable for amplification of target DNA material from red blood cells of a subject with a primer and detecting or recovering the amplified DNA, where the primers are described by Appendix 4:
[0000]
Primer (sense)
(SEQ ID NO: 24)
5′-CTG ACG ACA GCC ATG CA
Primer (antisense)
(SEQ ID NO: 25)
5′-GCA GTG GGG AAT ATT GGA CA.
[0040] Alternatively, a set of primers that amplify the same DNA fragment amplified by the two primers described above may be employed. These primers may be designed by methods known in the art and each may comprise 18-30 or more base pairs of the sequence amplified by the two primers above.
[0041] The biological sample used in the method described above or other methods described herein may be whole blood or a cellular component of whole blood, isolated anucleated red blood cells, isolated red blood cell precursors, such as erythroblasts, bone marrow or spleen cells, or subcellular fractions thereof, such as cellular lysates, supernatants or solid materials. Blood plasma or serum or other bodily fluids or tissues may also be used as a biological sample for the methods described herein. Those of skill in the art can select an appropriate biological sample for performance of PCR or select the appropriate conditions for producing an EMS signalized sample based on the disclosures of the patent applications incorporated by reference above. Representative biological samples include whole blood, isolated RBCs, subcellular components, extracts, or lysates of RBCs or their precursor cells, blood plasma or blood serum, spinal fluid, mucosal secretions, urine, saliva, bone marrow, or tissues.
[0042] A method for treating or for reducing the severity of a disease, disorder, or condition associated with the agent comprising treating a patient with an agent that reduces the titer of said agent or that reduces the amount of DNA amplified from a cell associated with it. This method may also comprise treating the patient with one or more antibiotics, such as azithromycin or a cyclin antibiotic; with one or more synthetic or natural immunostimulants, active vaccines, passive vaccines, antioxidants or antibiotics. A patient may also undergo treatment sequentially or simultaneously for viruses or other microorganisms or agents capable of causing an immunodeficient disease, disorder or condition. Treatment may be therapeutic or prophylactic and can include the administration of one or more anti-retroviral drugs or other antiretroviral treatments. The patient may be currently undergoing antiretroviral therapy or therapy to eradicate human immunodeficiency virus infection and treatment for the coinfecting bacterium initiated. Other modes of or supplemental treatments include treating the patient with one or more natural immunostimulants, antioxidants or antibiotics.
[0043] The methods described herein may employ samples from subjects or patients of different geographic origins or racial or genetic backgrounds. A subject or patient may be HIV-negative, recently (e.g., less than one year) HIV-positive, a patient who has been HIV-position for more than one or two years, an HIV-positive patient who has undergone or is undergoing anti-retroviral treatments or other kinds of patients who are HIV-positive such as those with AIDS or subjects at risk of becoming HIV-positive, developing AIDS or opportunistic infections. Patients may be of African origin or may have lived in Africa and exposed to biological and environmental agents there. Similarly, a patient may be of European or Caucasian origin or may have lived in Europe or America and exposed to biological and environmental agents there.
[0044] The invention is also directed to a method for treating a disease, disorder or condition associated with an agent described herein comprising contacting red blood cells with a substance that reduces the amount of DNA amplified from a red blood cell using (i) Primer Pairs 1 or 2, (ii) primers described by Appendix 3, (iii) or the primers described in Appendix 4 or primer pairs that amplify at least 20 consecutive nucleotides of the amplicons amplified by the primer pairs described above. Such a method for treating a disease, disorder or condition associated with an agent described herein may comprise contacting red blood cells of a subject with a substance that reduces the transmission of said agent to the red blood cell; may comprise replacing the red blood cells in a subject with red blood cells that are not associated with said agent or by stimulating the development of new red blood cells in said subject; or may comprise treating blood or red blood cells with an agent that that degrades, crosslinks or otherwise interferes or inactivates nucleic acids inside of or associated with a red blood cell.
[0045] Another aspect of the invention is a method for screening blood for red blood cells from which DNA can be amplified using (i) primer pairs 1 (SEQ ID NOS: 3 and 4) or 2 (SEQ ID NOS: 5 and 6), (ii) a pair of primers described by Appendix 3 (SEQ ID NOS: 7-14 or SEQ ID NOS: 15-23), (iii), the pair of primers described in Appendix 4 (SEQ ID NOS: 24 and 25); or a pair primers that amplify at least fifteen, twenty, twenty five, thirty, forty, fifty or more consecutive nucleotides of the same DNA as is amplified by the specific primers described herein. This method comprises contacting a sample of blood or red blood cells with these pairs of primers and detecting amplified DNA and selecting a blood sample from which DNA was amplified or alternatively selecting a blood sample from which no DNA was amplified. For example, a blood sample from which amplified DNA is detected may be further evaluated or cultured to determine the sensitivity of the red blood cells or the agent associated with them to antibiotic or other therapeutic treatments. Alternatively, a blood sample in from which no DNA is amplified may be assessed as being free of the agent associated with the DNA amplified by these primers.
Example 1
Detection of Amplified DNA in Red Blood Cells
[0046] Separation of Red Blood Cells
[0047] Standard procedures for separating RBCs from buffy coat and other peripheral blood components are known. Peripheral blood was processed on a Ficoll gradient to separate the buffy coat from red blood cells. After such separation it was found that DNA extracted from buffy coat cells was completely negative as determined by PCR using the primers described above while the same primers amplified DNA in the fraction containing the separated red blood cells. While it cannot ruled out that the agent detected is externally associated with the red blood cell membranes, it was found that amplified DNA was only detected in a supernatant prepared by a low speed (1,500 g×10 min.) centrifugation to remove the heavy components of a red blood cell lysate. This lysate was prepared by repeated freeze-thawing of red blood cells isolated from the buffy coat, strong shaking by vortex, and a low speed centrifugation (1,500 g×10 min.). A pellet and supernatant fraction were obtained and tested. The primers described above only amplified DNA in the supernatant fraction, but not in the pellet.
[0048] Growth on HL-60 Cells
[0049] HL-60 cells are an ATCC cell line of promyelocytic origin. Samples of HL-60 cells at a density of 5×105 cells per ml in RPMI medium supplemented with 10% fetal calf serum were inoculated with the supernatant of the red blood cell lysate described above. This lysate was obtained from the red blood cells of HIV-positive patients after freezing, thawing and vortexing as previously described. After culturing for 3 days at 37° C. the low speed (1,500 g×10 mins) supernatants of the cultures were tested by PCR for DNA amplified using Primer Pairs 1 and 2. DNA was amplified from all of these cultures up to a dilution of 10-8• The same results were obtained from culture supernatant that was passaged through a 0.45 micron filter.
[0050] Effects of Long-Term Antibiotic Treatment
[0051] Five HIV-positive patients were maintained on their antiretroviral therapy, but received for at least three months a daily antibiotic treatment (azithromycin 250 mg/day or doxycycline 100 mg/day). Blood samples were fractionated to recover a red blood cell fraction on day 0 and after 3 months of antibiotic. Results indicated that the amount of DNA amplified after 3 months of antibiotic treatment was significantly less than that amplified under the same conditions from the samples obtained on day 0.
[0052] Detection of Amplified DNA in Red Blood Cells of African and Caucasian Patients
[0053] Blood samples were obtained from African and European Patients who were HIV-negative or HIV-positive. Red blood cells were isolated from buffy coat and other blood components by separation on a Ficoll gradient as described above. Table 1 shows the results of amplification of red blood cell samples from these patients using Primer Pairs 1 and 2. Similar results were obtained using the primers described in Appendix 3. No DNA was amplified using Primer Pairs 3 and 4 for Chromosome 1 and 7 from the red blood cells of one European patient who was HIV-positive for a year or less. This suggests that in some Caucasians that the accumulation of this human DNA in the red blood cell fraction occurs late after infection and possibly under the selective pressure of antiretroviral treatment. However, amplified DNA was detected in this patient using the Primer Pairs 1 and 2 shown in Appendix 2, but the amplified DNA bands were weaker than those for chronically-infected HIV-positive patients.
[0000]
TABLE 1
Cultured cells
Caucasian
(HL60)
African
RBC:
HL60 +
RBC:
HIV+
RBC
HIV+
treated
extract
treated
with
from
with
antibiotics
HIV+
antibiotics
for 3
subject
RBC:
RBC:
WBC:
for 3
RBC:
RBC:
WBC:
months (0
No
(0 vs 3
HIV−
HIV+
HIV+
months
HIV−
HIV+
HIV+
vs 3 mos)
extract
days)
App. 2
Pair 1
rare
100%
0%
↓
0%
100%
0%
↓
—
↑
Pair 2
rare
100%
0%
↓
0%
100%
0%
↓
—
↑
Chr 1
Pair 1
+
+
−
+
−
+ or −*
+
−
Chr 7
Pair 1
+
+
−
+
−
+ or −*
+
−
+ in chronically infected and treated patients
− in recently infected patients
[0054] DNA Amplified Using Primer Pairs 1 and 2
[0055] MSP2 Primer Pairs 1 and 2 were used to perform PCR on red blood cells of HIV-positive subjects are removal of white blood cells and other blood components by Ficoll gradient separation. Primer Pairs 1 and 2 are shown below.
[0000]
Primer Pair 1
(SEQ ID NO. 3)
5′GCCTA CAGAT TAAAG GCT
18 mer
(SEQ ID NO. 4)
5′ATCAT ARTCA CCATC ACCTA
20 mer
Primer Pair 2:
(SEQ ID NO. 5)
5′CYTAC AGAGT GAAGG CT
17 mer
(SEQ ID NO. 6)
5′ATCAT ARTCA CCATC ACCTA
20 mer
[0056] The DNA bands amplified by PCR using Primer Pairs 1 and 2 were 100% homologous with human sequences (primer sequences excluded) present in data-banks for human genomic sequences, respectively in human chromosome 1 (clone RPII-332J14 GI:22024579, clone RP11-410C4 GI:17985906, and Build GRCh37.p5 Primary Assembly-) and in human chromosome 7 (PAC clone RP4-728H9 GI:3980548; human Build GRCh37.p5, and alternate assembly HuRefSCAF — 1103279188381:28934993-35424761).
[0057] Human Chromosome 1 and 7 DNA Sequences Described in Appendix 5
[0058] Appendix 5 shows the identities of human chromosome 1 and Chromosome 7 sequences that are amplified by primers described in Appendix 3. Primer sequences are underlined.
[0059] Primer Pair 3: Primer “hChr1114179308 S” upstream of, and “hChr1/14179853 AS” encompassing one end of the 237 bp amplicon related to chromosome 1 (546-bp long amplicon) were used to perform PCR on material from red blood cells isolated from other blood components by Ficoll gradient.
[0060] Primer Pair 4: Primers “hChr7/4292976 S” upstream of, and “hChr7/4294619 AS” downstream of the 213 bp amplicon related to chromosome 7 (1,643-bp long amplicon); and the primers described by Appendix 3.
Example 2
Method for Detecting Risk of Acquiring HIV Infection or Opportunistic Infection Associated with HIV Infection or Risk of the Progression of an HIV Infection or Opportunistic Infection
[0061] Blood is collected from a subject in the presence of EDTA as an anticoagulant. The red blood cells in the sample are separated from buffy coat and plasma components of blood using a Ficoll-Hypaque gradient according to the manufacturer's current protocol. DNA in the red blood cell sample is prepared and amplified using a QIAGEN® Fast Cycling PCR Kit or Taq PCR Core Kit (as described in the current QIAGEN® product catalog) using MSP2 primer pair 1:
[0000]
(SEQ ID NO: 3)
5′GCCTA CAGAT TAAAG GCT
and
(SEQ ID NO: 4)
5′ATCAT ARTCA CCATC ACCTA
or
MSP2 primer pair 2:
(SEQ ID NO: 5)
5′CYTAC AGAGT GAAGGCT
and
(SEQ ID NO: 6)
5′ATCAT ARTCA CCATCACCTA.
[0062] Amplified DNA is resolved by gel electrophoresis and detected by staining with ethidium bromide. A subject is classified as being at a higher risk for acquiring HIV or HIV-associated opportunistic infection or for when amplified DNA is detected.
[0063] FIGS. 1 and 2 were produced on different dates. Lane numbers 1 and 2 are duplicates (from HIV-negative source) and lanes 3 and 4 are duplicates (from HIV-positive source). All DNA samples were extracted from a third passage HL60 cells exposed to an agent originating from red blood cells of HIV-negative or HIV-positive patients. These panels represent gel electrophoresis pictures of amplicons obtained by 70 cycles of PCR using primers derived from the Ehrlichia MSP2 gene (213 bp) and primers derived from the 16s ribosomal gene of Anaplasma (690 bp). The bands on the left sides of FIGS. 1(A) and 1(B) show the 213 bp fragment mapped to human chromosome 7 amplified by the Ehrlichia MSP2 primers. The bands on the right sides of FIGS. 1 and 2 show the 690 bp fragment amplified by the Anaplasma primers (SEQ ID NOS: 24 and 25).
Example 3
Method for Detecting Microorganism Associated with Risk or Progression of HIV Infection or Opportunistic Infection Associated with Infection with HIV
[0064] Blood is collected from a subject in the presence of EDTA as an anticoagulant. The red blood cells in the sample are separated from buffy coat and plasma components of blood using a Ficoll-Hypaque gradient according to the manufacturer's current protocol. DNA in the red blood cell sample is prepared and amplified using a QIAGEN® Fast Cycling PCR Kit or Taq PCR Core Kit (as described in the current QIAGEN® product catalog) using the primer pair
[0000]
(SEQ ID NO: 24)
5′-CTG ACG ACA GCC ATG CA
and
(SEQ ID NO: 25)
5′-GCA GTG GGG AAT ATT GGA CA.
[0065] Amplified DNA is resolved by gel electrophoresis and detected by staining with ethidium bromide. A subject is identified as being infected with a microorganism when amplified DNA is detected.
[0000]
APPENDIX 1
Primers were designed
to based on include a
conserved 16S
rickettsiales 16S
region of DNA which
ribosomal DNA
Primers designed based
recognizes
on Rickettsiales 16s
Rickettsiales and
ribosomal DNA gene
SEQ ID NO:
also Propionobacter
5′-GCAACGCGAAAAACCTTACC
SEQ ID NO: 1
Rick l6S 929S
(20 mer) Tm = 45.0° C.
5′-GACGGGCAGTGTGTACAA
SEQ ID NO: 2
Rick 16S 1373AS
(18 mer) Tm = 45.0° C.
[0000]
APPENDIX 2
MSP2 Primers
SEQ ID NO:
MSP primer pair 1
5′-GCCTACAGATTAAAGGCT
SEQ ID NO: 3
18-mer
5′-ATCATARTCACCATCACCTA
SEQ ID NO: 4
20-mer
MSP primer pair 2
5′-CYTACAGAGTGAAGGCT
SEQ ID NO: 5
17-mer
5′-ATCATARTCACCATCACCTA
SEQ ID NO: 6
20-mer
[0000]
APPENDIX 3
Human chromosome 1 and 7 primers
Chromosome 1 primers
SEQ ID NO:
Primer #1
5′-CCTTACACTCAGCCAGACAT
SEQ ID NO: 7
hChr1/14179308 S
Primer #2
5′-CCAGGTGTGTGGCTTATACA
SEQ ID NO: 8
hChr1/14179853 AS
Primer #3
5′-CATAGCTTCCTAGTAAGTAGACCAG
SEQ ID NO: 9
hChr1/14180006 S
Primer #4
5′-AGGGGAGTCTGAGATGGT
SEQ ID NO: 10
hChr1/14180401 AS
Primer #5
5′-ACTGGAGAGGTGGAGGTT
SEQ ID NO: 11
hChr1/14181093 AS
Primer #6
5′-GGTAATTCCTATGTGCGAGGT
SEQ ID NO: 12
hChr1/14181390 AS
Primer #7
5′-TCAAAAGACAGTGGTGACTCT
SEQ ID NO: 13
hChr1/14177990 S
Primer #8
5′-ATGTCTGGCTGAGTGTAAGG
SEQ ID NO: 14
hChr1/14179327 AS
Chromosome 7 primers
SEQ ID NO:
Primer #1
5′-ATGTAGTTGAGCAGTTTTGAATGA
SEQ ID NO: 15
hChr7/4292976 S
Primer #2
5′-TCCTGCCTTAGTGAGGATCT
SEQ ID NO: 16
hChr7/4293490 S
Primer #3
5′-ATGAATAGGTGATGGTGATGACT
SEQ ID NO: 17
hChr7/4293941 AS
Primer #4
5′-CCGTCATTTAAGCCTTTAATCTCA
SEQ ID NO: 18
hChr7/4294102 S
Primer #5
5′-GTAGTCTTTTGGCATCTCTTTGTA
SEQ ID NO: 19
hChr7/4294619 AS
Primer #6
5′-CAGCCTGGAGAACAGAGTG
SEQ ID NO: 20
hChr7/4294983 AS
Primer #7
5′-GATCTAGCAGTTCATAGGAAGGAA
SEQ ID NO: 21
hChr7/4295251 AS
Primer #8
5′-GGCTGAAACAATGGGGTTTT
SEQ ID NO: 22
hChr7/4291579 S
Primer #9
5′-TTTAGTAGACCCCTCGACCA
SEQ ID NO: 23
hChr7/4293175 AS
[0000]
APPENDIX 4
Anaplasma 16s rDNA based primers
SEQ ID NO:
Primer
5′-CTGACGACAGCCATGCA
SEQ ID NO: 24
Sense
Primer
5′-GCAGTGGGGAATATTGGACA
SEQ ID NO: 25
anti-
sense
[0000] APPENDIX 5 The human chromosome 1 sequence amplified by the MSP2 primers shown below: primer identifiers Sequence MSP2 primer #3) Ac/mMSP2-1019S 5′-CYTACAGAGTGAAG GCT (SEQ ID NO: 5) MSP2 primer #5) Ac/mMSP2-1128AS 5-ATCATARTCACCATC ACCTA (SEQ ID NO: 6) Y = T or C; R = G or A
Sequence of the 237 bp amplicon (SEQ ID NO: 26) generated with these two primers by PCR:
[0000]
5′- ATCATAGTCA CCATCACCTA CCAGCTGTATAAGCCACACA
CCTGGGAGTC CTCCTAGCCT TTTTCCTCCT CCTCTCATCC
TCCATATCCC ATTGACCGTC AGGGCCTACT GAGTCTACAC
TCCAATTTTC TTTTAAATCT ATCCCCACTG CCACTGTCCT
AGTCTAAGGC AATACCATCT GGTCACCCAG ATCATTCCAT
AGCTTCCTAG TAAGTAGACC AGCCTTCACT CTGTAAG -3′
[0066] underlined nucleotides: primer sequence.
[0067] bold nucleotides: divergent nucleotides between MSP2 primers and the corresponding homologous human Chr 1 sequence.
[0068] The human chromosome 7 sequence amplified by the MSP2 primers shown below:
[0000] Primer identifiers Sequence MSP2 primer #2) AphMSP2- 5′-GCCTACAGATTAA 1019S AGGCT(SEQ ID NO: 3) MSP2 primer #5) Ac/mMSP2- 5′-ATCATARTCACCA 1128AS TCACCTA(SEQ ID NO: 6) Y = T or C; R = G or A
Sequence of the 213 bp amplicon (SEQ ID NO: 27) generated with these two primers by PCR:
[0000]
5′- GCCTACAGAT TAAAGGCT TA AATGACGGTG
AAAACTTAGT ATTCTTTGGG TGGACAATAG TGAAATTTGC
ACTTTGGACA GAATGACATG TACAAAAAGA GTCAAGAAAC
TTTTTAATCT ATTTAAAGGA CTCAAAGTAA TTTGTGAAGG
CCATAGCGTA AAATAACTTC AGTGGATGGA ATGGGATGAT
GAA TAGGTGA TGGTGACTAT GAT -3′
[0069] underlined nucleotides: primer sequence.
[0070] bold nucleotides: divergent nucleotides between MSP2 primers and the corresponding homologous human Chr 7 sequence.
[0071] Identities of the human sequences amplified by the human chromosome 1 primers or human chromosome 7 primers described in sections A) and B) respectively below.
[0072] The sequences described below, except for the primers MSP2-derived amplicons, are corresponding to human genetic sequences available in NCBI genome databanks (www.ncbi.nlm.nih.gov/projects/genome).
[0073] A) Genomic Human Chromosome 1 Primers #1 (hChr1/14179308 S) and #2 (hChr1/14179853 AS) PCR-Amplified 546 bp Amplicon (SEQ ID NO: 28):
[0074] identifier: Amplicon hChr1/14179308-14179853
[0000]
5′- CCTTACACTC AGCCAGACAT ATATTTGT GT TTTGTTATCC
ATGTGCACAG AGACTTTGGC ATTCTGGGTG AAGGAAGAAA
GAAGAGAATA TACATGGAAA CCCAGGGGTA AGAGAAAAGG
ACAACAGAGA ATGTGGCATG GGGAATGCTC TGCTGGGTCA
CATTGAATGG TTCTGAACCA CTGTGGAAAA AAAGGAGTTA
GAAAGAATCA GATGCCGAAG GAGCCAATTT TCACAATACT
CCGAGACTCA GGGCAAAAGC AGCCTTGTTC TAGTAGCCTA
TGGGTAAAAG AAGACACAGA ACTGAGGGGA GGACTTTTCC
CCTGAGTCCA CCACAAACCG CCATGGAGCT GAGGCAGCCT
GAAGTCTCAG GGGCATGGGA GGGATTTGCC TTTTGGATTT
CTCCAATGGG ATGTCTTACA GGCACTTCAT ATTTAGCAGA
TCCAAAACTT AACTCAGATA CTCCTCTTGC CATATCTGTT
CCTCTTGCTG TGTTCCTGAC CATGATTATC ACCATCACCT
ACCAGC TGTA TAAGCCACAC ACCTGG -3′
[0075] underlined nucleotides: hChr1 genomic primer sequence.
[0076] bold nucleotides: homologous extremity of the 237 bp amplicon obtained with the primers MSP2#3-5.
[0077] B) Genomic Human Chromosome 7 Primers #1 (hChr7/4292976 S) and #5 (hChr7/4294619 AS) PCR-Amplified 1,644 bp Amplicon* (SEQ ID NO: 29):
[0078] Identifier: Amplicon hChr7/4292976-4294619
[0000]
5′- ATGTAGTTGA GCAGTTTTGA ATGA GTTTCT TAATCCTGAG
TTCTAGTTTA AGAAAATATT AAAAATAAAA AATTATGTCA
CCAACTAAAT TTTTACTGCA GATAATCATA AGTTGGTTAG
ATTGGACCTT CATTGTGAAA TGCAGTAACT TTGGTTTAAG
CAATATCCAA AACCAGAAAT TGGTCGAGGG GTCTACTAAA
TTCCGTTTTC TTTTGTTCTA AACAATTAAA CATTCTAAAA
TTTAGGGAAA AGGACCAATG GTGCAAACAT TTTAGAGCTG
ACAGTTGTGT GCCATATGCC ATGATTCTGT TACAAATGAA
CAGTATTCAG ATTCAAAATC AGTGTAAACA CTGTGTGTGT
GTGTGTGTGT GTGTGTGTGT GTGTGTGTGT GTATTTTACA
CAGCCATTTA AATATTAACC GCCTTTGAGT ATTAGGGGAA
AAAACAGAAA CTAAAAGCGA ATATATTTGT TCCTGAATCC
TCCCACCAAA CCACTTTTTA AATTAATTAT ATT TCCTGCC
TTAGTGAGGA TCT TCCTATT CATCAAAGAT AAAATACCAA
ATATAATTTA CTCTCCTTCT CTACCTCACC CCCAATATTC
AACAATTCCC TATTTTATTT TGATTTTACT TCCTATTGTC
TCTCAGTGCA TCCTTACTAC TGGTTTCTGG CCTCAATGTC
TCTTTCCATA AATACTTCCT CCAGGGCTTC AGCAGTGTAT
ATTGCAATCC ATGAGTGTGA TGCCCTTATA AGCTGTACAG
GCACAACCCA GGCAAACATA CACAATGACC ATAATCATAA
CAGTCATTAC TGGTGCCTTT ACTCTGGTTT TATCCATCCC
CCAACAATCC TTTAATCCTC CACTAGAGTT TATTCTTTTA
AGTGAAAATC TGGATTCTTA TCTCCCCTAG TATGTATCTC
TTAGTGAATT TTTATATGAG ATAGTCATCA CCATCACCTA
TTCATCATCC CATTCCATCC ACTGAAGTTA TTTTACGCTA
TGGCCTTCAC AAATTTACTT TGAGTCCTTT AAATAGATTA
AAAAGTTTCT TGACTCTTTT TGTACATGTC ATTCTGTCCA
AAGTGCAAAT TTCACTATTG TCCACCCAAA GAATACTAAG
TTTTCACCGT CATTTAAGCC TTTAATCTCA GGATCTCACA
ATAAATACAA TCACTCTTTC CTATATGCCT AATCTTCTGC
TTGAGCATAA TTTTAATGTG CTAACTATTC TGTAATTATA
TATATATTTT TAATTCAGCC ACTTCTCTCA CTAGAAAGTG
AGTTTGTTGA AATCAGGGTA AGTATATTTT ATGTTTGGAT
GAATTCCCCA TCACAATACT TCACATGTAG TTATCTAGTC
ACCAATTTTT ATTGAAATTA ATTGTACATA TAATAAAACT
TTAATATAAA ATGTTTCTCT TGAGGGGAGA TTTTCTTTGT
AAAACTATCC TTCTGAGCTT TGTGATGTGA TGATTGTCTA
ATGTCTGTTG CAAGATTAAG GAAAATGTAT TTGAATGCAA
ATGAACTTAC ACTGTCATAC CAAAAGTGTG ATAATTTCTT
GCTCCTGAAC TCACTCTCCC TACCTGCCTA TTAAAATCAG
AATACACAGA TCTGTATCTG TACAAAGAGA TGCCAAAAGA
CTAC -3′
[0079] underlined nucleotides: hChr7 genomic primer sequence.
[0080] bold nucleotides: homologous extremity of the 213 bp amplicon obtained with the primers MSP2#3-5.
[0081] The internal underlined nucleotides correspond to the sequence of primer hChr7/4293490 S (hChr7#2).
Please note that this amplicon length has been reported as 1,643 bp long in previous documents. The correct length is 1,644 bp.
[0083] Other amplicons obtained from HIV positive or HIV-negative patients or from both using the human chromosome 1 or human chromosome 7 primers described in sections C) and D) below.
[0084] C) Genomic Human Chromosome 1 Primers #3 (hChr1/14180006 S) and #4 (hChr1/14180401 AS) PCR-Amplified 396 bp Amplicon (SEQ ID NO: 30):
[0085] Identifier: Amplicon hChr1/14180006-141a0401
[0000]
5′- CATAGCTTCC TAGTAAGTAG ACCAG CCTTC AGTCTGAGCC
CTCCTCGGTC CTTCCTCCCC AGTGCTGCTG GAGTAATCCT
TCTAACACAA CAATGAAAGC AGGTCACTGC GGCTCAAATG
ATGTCAGCGG CTTTATCATC CATGTTGCCT GGCTTTTCAC
AGGCATGTCT TGCAGTGCAG CCTTATAACT CTCTCAACAC
AACTCTGTAT CCTCCTCATT CTTCATGCTT TTATAATGTC
AAGCCATGTG ACACTCCCTA AATATACCAT GTTTTCTCTT
TTTCCTCCTC CCCCTCTCTC ATTTGCAGCT TCCCATACTT
ATCTTCCTAA ACACTACTCT TTTTGAAATG TTTATTTCAA
GGGTTTCTTA TCTTTTAA AC CATCTCAGAC TCCCCT -3′
[0086] underlined nucleotide: primer sequences.
[0087] bold nucleotide: homologous extremity of the 237 bp amplicon obtained with primers MSP2#3-5.
[0088] D) Genomic Human Chromosome 1 Primers #3 (hChr1/14180006 S) and #5 (hChr1/14181093 AS) PCR-Amplified 1,088 bp Amplicon (SEQ ID NO: 31):
[0089] Identifier: Amplicon hChr1/14180006-14181093
[0000]
5′- CATAGCTTCC TAGTAAGTAG ACCAG CCTTC AGTCTGAGCC
CTCCTCGGTC CTTCCTCCCC AGTGCTGCTG GAGTAATCCT
TCTAACACAA CAATGAAAGC AGGTCACTGC GGCTCAAATG
ATGTCAGCGG CTTTATCATC CATGTTGCCT GGCTTTTCAC
AGGCATGTCT TGCAGTGCAG CCTTATAACT CTCTCAACAC
AACTCTGTAT CCTCCTCATT CTTCATGCTT TTATAATGTC
AAGCCATGTG ACACTCCCTA AATATACCAT GTTTTCTCTT
TTTCCTCCTC CCCCTCTCTC ATTTGCAGCT TCCCATACTT
ATCTTCCTAA ACACTACTCT TTTTGAAATG TTTATTTCAA
GGGTTTCTTA TCTTTTAA AC CATCTCAGAC TCCCCT GGGG
ATTACCCCTT TTCCTATGTT TTTATTGTAG CATCCTCACA
AATTCACTTT AGTTCCTTCG CATTCTGGTG TCGCTATATA
TTAGTGGGAC TATGTCCCCA TTAACCTGTT AGATCTCTTG
AGAAAAGGGA CATGTCTTTT CATCTTGAGT TCCCCAATAC
TTAGTATTGT GCTTAGCATA TGCTAGGTGC TCAGTAAATA
TTTGATATGT GTGTGAACGA ATGAATCAAT CAATCAATAA
CAAATGACAG ACAAACTCCA ACCCCCAAAC CTAAAAAAAA
AAAATCCAAA CTTTCCCCTT GCTCTTAGTG TAGATACTGC
TCATCAACAT AAGGCAAATT CTTCCTGCGC GTCTCAATAC
AGAGGAGGCG AGAACTCACA GAATCACAGA ATTAGAGCAC
TGGCTTTGGC ATGAGAACAC CCTGAGTTAA AATCTGGCTT
CTGCTATTTA TTAGCCACAT GACAGTGAAT CTCCTTGAGC
TTCTGTTTTG TACAAACTTA AGTTTGGCTT TGTGATCTTA
TTCCTCTTTG GTGCATCTGT ACAACCCAAC TGCTTATTCA
TATGACACTG CTAAAACATG CCTTGCCTTC TCCCCCACTT
TTTTTTTTGG AGACAGAATC TCCCTTTGTC ACCCAGGCTG
GAATTCAGTG GCGTGATCTC GGCTCACTGC AACCTCCACC
TCTCCAGT
[0090] -3′
[0091] underlined nucleotides: primer sequences.
[0092] Bold nucleotides: homologousd extremity of the 237 bp amplicon obtained with the primers MSP2#3-5.
[0093] The sequence of the 396 bp amplicon hChr1/14180006-14180401 (C) is included in the larger size amplicon 1,088 Amplicon hChr1/14180006-14181093.
[0094] The internal underlined nucleotides correspond to the reverse-complement sequence of primer hChr1/14180401 AS (hChr1#4).
[0095] E) Genomic Human Chromosome 7 Primers #2 (hChr7/4293490 S) and #6 (hChr7/4294983 AS) PCR-Amplified 1,494 bp Amplicon (SEQ ID NO: 32):
[0096] Identifier: Amplicon hChr7/4293490-4294983
[0000]
5′- TCCTGCCTTA GTGAGGATCT TCCTATTCAT CAAAGATAAA
ATACCAAATA TAATTTACTC TCCTTCTCTA CCTCACCCCC
AATATTCAAC AATTCCCTAT TTTATTTTGA TTTTACTTCC
TATTGTCTCT CAGTGCATCC TTACTACTGG TTTCTGGCCT
CAATGTCTCT TTCCATAAAT ACTTCCTCCA GGGCTTCAGC
AGTGTATATT GCAATCCATG AGTGTGATGC CCTTATAAGC
TGTACAGGCA CAACCCAGGC AAACATACAC AATGACCATA
ATCATAACAG TCATTACTGG TGCCTTTACT CTGGTTTTAT
CCATCCCCCA ACAATCCTTT AATCCTCCAC TAGAGTTTAT
TCTTTTAAGT GAAAATCTGG ATTCTTATCT CCCCTAGTAT
GTATCTCTTA GTGAATTTTT ATATGAGATA GTCATCACCA
TCACCTATTC ATCATCCCAT TCCATCCACT GAAGTTATTT
TACGCTATGG CCTTCACAAA TTACTTTGAG TCCTTTAAAT
AGATTAAAAA GTTTCTTGAC TCTTTTTGTA CATGTCATTC
TGTCCAAAGT GCAAATTTCA CTATTGTCCA CCCAAAGAAT
ACTAAGTTTT CACCGTCATT TAAGCCTTTA ATCTCAGGAT
CTCACAATAA ATACAATCAC TCTTTCCTAT ATGCCTAATC
TTCTGCTTGA GCATAATTTT AATGTGCTAA CTATTCTGTA
ATTATATATA TATTTTTAAT TCAGCCACTT CTCTCACTAG
AAAGTGAGTT TGTTGAAATC AGGGTAAGTA TATTTTATGT
TTGGATGAAT TCCCCATCAC AATACTTCAC ATGTAGTTAT
CTAGTCACCA ATTTTTATTG AAATTAATTG TACATATAAT
AAAACTTTAA TATAAAATGT TTCTCTTGAG GGGAGATTTT
CTTTGTAAAA CTATCCTTCT GAGCTTTGTG ATGTGATGAT
TGTCTAATGT CTGTTGCAAG ATTAAGGAAA ATGTATTTGA
ATGCAAATGA ACTTACACTG TCATACCAAA AGTGTGATAA
TTTCTTGCTC CTGAACTCAC TCTCCCTACC TGCCTATTAA
AATCAGAATA CACAGATCTG TATCTG TACA AAGAGATGCC
AAAAGACTAC TTTCATGCTG CAACATGATT ATGTGCCCCC
AAAACCTGGA TATTTATAGT ATAGTATCCA GTATTTTCAA
TCTAAGCTGT ACTGGAGCCC GAAGCTAAAG GAAAATTAGT
AATACTGATG CTCCCTTTAT TTAAACTTTT AAGACTTTAT
CATGGCATTA ATTTTGACTT TTAAAAATAT TATCATTTTT
TTTGGACCCC CTTAAATTTT GTTCCCGAGT TGAATGCCTC
ACTGGGACTT GGGTGAATGA ATGCTCACCC TAGTCCTAGA
TTAGGTACTC ATCTTAAATA CTGTTAGTTT GGGGTGGTTT
TTTTTTTTTT TTTTTTTTTT TTTTTGACAG AGCCT CACTC
TGTTCTCCAG GCTG -3′
[0097] underlined nucleotides: hChr7 genomic primer sequence.
[0098] bold nucleotides: homologous sequence of the 213 bp amplicon obtained with the primers MSP2#2-5.
[0099] A part of the sequence 1,644 bp amplicon hChr7/4292976-4294619 (B) is included in the amplicon 1,494 bp Amplicon hChr7/4293490-4294983 (E). The internal underlined nucleotides correspond to the reverse-complement sequence of primer hChr7/4294619 AS (hChr7#5).
APPENDIX 6
[0100] An amplicon of the 16s rDNA primers (SEQ ID NOS: 24 and 25) is shown below. The amplified DNA originated from the red blood cells of an HIV-negative subject passaged in HL60 cells. Similar DNA is amplified from samples originating from red 5 blood cells of HIV-positive subjects.
[0101] Amplicon (SEQ ID NO: 33) from HIV-negative subject obtained using primers (SEQ ID NOS: 24 and 25):
[0102] >TS6-EMK-4-HIV-_Anae#2-5 wo/primers seq.=681 bp
[0000]
5′-GCACCTGTATGT GAATTC CCGAAGGCACTCCCGCATCTCTGCAGG
ATTCTCACTATGTCAAGACCAGGTAAGGTTCTTCGCGTTGCATCGAAT
TAAACCACATGCTCCACCGCTTGTGCGGGCCCCCGTCAATTCATTTGA
GTTTTAACCTTGCGGCCGTACTCCCCAGGCGGTCTACTTATCGCGTTA
ACTGCGCCACTAAAGTCTCAAGGACCCCAACGGCTAGTAGACATCGTT
TACGGCGTGGACTACCAGGGTATCTAATCCTGTTTGCTACCCACGCTT
TCGAATCTCAGTGTCAATATTATGCCAGGAAGCTGCCTTCGCCATCGG
CATTCCTCCAGATCTCTACGCATTTCACCGCTACACCTG GAATTC TAC
TTCCCTCTCACATATTCTAGCACCACCAGTATCACATGCAGTTCCCAG
GTTAAGCCCGGGGATTTCACATGTGACTTAATGAGCCACCTACACTCG
CTTTACGCCCAGTAATTCCGATTAACGCTCGCACCCTCTGTATTACCG
CGGCTGCTGGCACAGAGTTAGCCGGTGCTTATTCTGCAGGTAACGTCT
AATCTAATGGGTATTAACCATTAGCCTCTCCTCCCTGCTTAAAGTGCT
TTACAACCAAAAGGCCTTCTTCACACACGCGGCATGGCTGGAT CAGG
GTTGCCCCCCATT-3′ | A method for identifying a risk factor for diseases, disorders or conditions, such as those caused by human immunodeficiency virus, using the polymerase chain reaction and specific primers. Methods for treating patients having these diseases, disorders or conditions by antimicrobial treatment of the risk factor by combined antiviral and antibacterial treatment or by sustaining or stimulating the subject's immune system. Methods for screening biological products including red blood cell preparations. Primers and methods for detecting nucleic acids or microbial agents associated with red blood cells, such as those associated with red blood cells in subjects infected with HIV and undergoing antiretroviral therapy. | 2 |
BACKGROUND OF THE INVENTION
The present invention relates to switching devices for controlling vehicle headlamps and fog lamps. Heretofore, switches employed for controlling high and low beam headlamps and providing a flash-to-pass function and also incorporating the switching function for the fog lamps have been actuated by a stalk or lever mounted on the steering column. Typically, movement of the stalk or lever in the direction coinciding with the axis of the steering column has been employed for changing the headlamp from the low beam to the high beam mode and simultaneously switching off the fog lamps in the event same were on at the time of the user actuating the stalk. Heretofore, the switching contacts employed for effecting the switching functions were of relatively low current carrying capacity in order to render the switch compact and inexpensive; and, consequently, the switching contacts were only used to energize relays for switching the current for the headlamps and fog lamps.
Referring to FIG. 11, a schematic for a prior art flash-to-pass headlamp switching system is illustrated in which a stalk operated switch assembly 1 is connected to the vehicle power supply at terminal 2 which is connected through junction 3 to the common terminal 4 of a single pole double throw (SPDT) switch having a side contact 5 which is connected through connector terminal 6 to a low beam headlamp. The opposite side contact 7 of the SPDT switch is connected through connector terminal 8 to an input terminal 9 of a relay 10. Side contact 7 is also connected to a side contact 11 of a single pole single throw switch having user moveable actuator 12 for, upon closing of the switch, connecting side terminal 11 to an opposite side terminal 13 which is connected to the power junction 3.
The input terminal 9 of relay 10 is connected to one lead of a relay coil 14 which has the opposite lead connected through terminal 15 to ground. A resistor R is provided in parallel with the coil. A power input terminal 16 is connected to the vehicle power supply and to the common terminal 17 of a second single pole double throw switch having one side contact 18 thereof connected through an output terminal 19 to a vehicle fog lamp. A second side contact 20 is disposed opposite the switch contact 18 and is connected through connector terminal 21 the vehicle high beam lamp. Thus, user movement of switch actuator 12, which may be effected by a steering column mounted stalk lever, also causes switch member 4 to break the power to the low beam headlamp and apply power to the high beam input of the relay 10; and, simultaneously the switch actuator 4 is latched to secure power to the high beam input to the relay. Energization of relay coil 14 causes switch member 17 to break the current to the fog lamps and switch power to the high beam headlamp.
It has been desired to maintain the simple single stroke lever actuation of the steering column mounted stalk lever for performing the high beam switching and flash-to-pass function; and, thus limited switching motion is available to perform the various switching functions required for flash-to-pass operation.
In the high-volume, mass-production of motor vehicles, it has been desired to minimize the cost of electrical switching functions and thus it has been desired to find a way or means of eliminating the relays required for the high beam and flash-to-pass switching functions of the headlamps and fog lamps and direct switching of the head lamp current yet retain the use of the steering column mounted stalk lever for user actuation of the flash-to-pass function.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a reliable and robust switching assembly for switching on and off the high beam headlamps and switching off the fog lamps, if on, prior to energizing the high beam headlamps in order to minimize the current flow in the switch members and contacts.
The present invention performs the aforesaid switching operations, including flash-to-pass mode switching with a bi-stable rotary switch responsive to successive movement of a sliding shorting bar switch which is actuated in a push-push mode typically by the user movement of a steering column mounted stalk lever.
A user pull on the stalk lever effects push movement of the shorting bar which initially breaks contact with a power bus strip and a terminal strip connected to the fog lamps; and, subsequently as the stroke of the sliding bar continues, a powered bus strip is connected to a terminal strip wired to the high beam headlamps.
As the stalk lever push actuator stroke continues the bi-stable switch is rotated to connect the powered bus strip to the high beam contact strip by a different path thereby shunting the sliding actuator contact. The bi-stable rotary switch also breaks a separate connection in the current path between the powered terminal bus strip and the fog lamps to prevent re-energization of the fog lamps and similarly breaks a connection in the low beam circuit. The bi-stable rotary switch is latched in the actuated position; and, upon release of the sliding actuator to return to the neutral position, the high beam headlamps are maintained energized by the rotary switch and the fog lamp and low beams are maintained as de-energized. A second or subsequent actuation of the stalk lever by the user effects movement again of sliding contact in the push mode and reverses the movement of the bi-stable rotary switch and de-energizes the low beam headlamps, fog lamps and de-energizes the high beam in reverse sequence. The rotary switch is latched in the second position until the subsequent push movement of the sliding actuator.
The present invention thus provides a unique stalk lever operated push--push actuated switch assembly which provides a sequential deactivation of fog lamps, actuation of high beams and deactuation of low beams by direct action of sliding contacts on a planar array of terminal strips capable of handling the various headlamp currents directly and thus eliminates the need for relays and results in a lower cost yet robust and reliable switching arrangement.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the switch assembly of the present invention with the terminal strip cover removed showing the internal components;
FIG. 2 is a section view taken along section indicating lines 2--2 of FIG. 1;
FIG. 3 is an axonometric view of the assembly of FIG. 1;
FIG. 4 is an exploded view of the assembly of FIG. 3;
FIG. 5 is a schematic of the switching arrangement of the terminal strips showing the push actuator in the neutral position with the low beam headlamps and fog lamps energized;
FIG. 6 is a view similar to FIG. 5 showing the sliding actuator of FIG. 5 partially actuated prior to actuation of the bi-stable rotary switch with the high beam headlamps energized and the fog lamps de-energized;
FIG. 7 is a view similar to FIG. 6 with the sliding actuator moved to its fully actuated position and the rotary switch actuated to provide a second break in the fog lamp circuit and a shunt path for energization of the high beam headlamps;
FIG. 8 is a view similar to FIG. 7 with the sliding actuator returned to the neutral position and the rotary switch latched in the position of FIG. 7;
FIG. 9 is a sequence diagram of the actuation of the contacts by the sliding actuator;
FIG. 10 is a sequence diagram of the contact actuation of the bi-stable rotary switch;
FIG. 11 is a circuit schematic of a prior art relay energized headlamp switching system;
FIG. 12 is a circuit schematic of the switching arrangement of the present invention;
FIG. 13 is a plan view of the switch assembly of the present invention with the actuating stalk lever in the zero or neutral position;
FIG. 14 is a view similar to FIG. 13 with the actuating stalk lever pulled for 2° notation about the pivot;
FIG. 15 is a view similar to FIG. 13 with the actuating stalk lever pulled for 4° rotation about the pivot;
FIG. 16 is a view similar to FIG. 13 with the actuating stalk lever pulled for 6° rotation about the pivot; and,
FIG. 17 is a view similar to FIG. 13 with the actuating stalk lever pulled for about 7.3° rotation about the pivot.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 through 4, the switch assembly of the present invention is indicated generally at 30 and includes a base or housing 32 having a push-type actuator 34 or Beam Select plunger slidably received therein and retained by snap tabs 36, 38. The sliding actuator 34 has a generally U-shaped configuration in plan view and has the oppositely disposed parallel legs 40, 42 thereof slidably guided by ribs or ways 44, 46 formed in the housing 32 which respectively engage grooves 48, 50 formed in the legs 40, 42 of the actuator 34 for guiding the sliding movement thereof A pair of stops 35 formed on the sides of housing 32 serve to limit the stroke of actuator 34.
The sliding actuator 34 has an electrically conductive contact member 52 mounted on the upper surface thereof by flanges 54, 56 provided on the ends thereof and which flanges are received in grooves 58, 60 respectively formed in the upper surface of the leg 40. A second contact member 62 similarly has a pair of downwardly extending end flanges 64, 66 which are received respectively in grooves 68, 70 formed in the upper surface of leg 42 of actuator 34. Contact 52 has a pair of spaced, raised, preferably cylindrical, contact surfaces 53, 55 provided thereon; and, contact 62 also has a pair of spaced, raised, preferably cylindrical contact surfaces 63, 65 provided thereon.
Actuator 34 has a centrally disposed upstanding post or projection 72 provided thereon which is rotatably received in a bore 74 provided in a flipper 76 which is rotatably mounted on the post 72. Flipper 76 has a wedge or chiseled contact surface 78 formed on the end thereof which is intended for contacting an associated member as will hereinafter be described.
Flipper 76 is biased to the center by a spring finger member 77 formed integrally with actuator 34. Clockwise and counterclockwise rotation of flipper 76 about post 72 is limited by a curved track 79 formed in the base of housing 32 which track is engaged by a downwardly extending pin 75 formed on the undesirable of flipper 76.
Housing 32 also has an upstanding post or projection 80 formed thereon which is received in a bore 82 provided in a rotary switch member 84 which is thus rotatably received over the post 80.
Switch member 84 has disposed, in diametrally oppositely spaced arrangement, a third contact member 86 having a pair of downwardly extending end flanges 88, 90 formed thereon which are respectively received in grooves 92, 94 formed in the upper surface of switch member 84. A fourth contact member 96 is disposed on the opposite side of bore 82 from contact 86 in generally spaced parallel arrangement therewith, the contact 96 having also a downwardly extending pair of end flanges 98, 100 which are respectively received in grooves 102, 104 formed in the upper surface of switch member 84.
The rotary switch member 84 has a bi-stable camming surface formed in the periphery thereof which comprises a pair of V-shaped notches 106, 108 formed on opposite sides of an apex 110 which is disposed equidistant from grooves 92, 104.
The rotary switch member 84 also has a pair of recesses 112, 114 formed on the periphery thereof and angularly displaced circumferentially from the notches 106, 108 with the recesses forming a common apex 116 therebetween to thus form a pair of detent surfaces.
A plunger 118 is slidably received in an aperture 120 formed in a recess 122 provided in the housing; and, the plunger 118 is biased outwardly of the recess by a spring 124. The plunger 118 has a generally spherical end 126 which is in contact with the detent surfaces 112, 114. It will be understood that the arrangement of the plunger and detent surfaces is such that the rotary switch member 84 is latched into either a position where the plunger end 126 engages recess 114, in which position the rotary switching member 84 will be rotated slightly clockwise from the position shown in FIGS. 1, 3 and 4, or to a position where the member 84 is rotated counterclockwise slightly from the position shown in FIGS. 1, 3 and 4. It will be apparent from the drawings that the orientation of the apex 78 and the apex 116 coincide respectively with the center position of the flipper 76 and the plunger end 126.
Referring to FIGS. 5 through 10, 12 through 17 and Table I, the switching operation of the actuator 34 and the rotary switching member 84 are shown in dashed outline in FIGS. 5 through 8 and in solid outline in FIGS. 13 through 17 in their various operating positions as will be further described in detail.
Referring to FIGS. 5 through 8, the pattern for the switching terminal strips which are provided on the undersurface of an unshown cover for housing 32 is illustrated schematically. A plurality of terminal strips, each disposed for wiping contact with one of the contacts 52, 62, 86, 96 respectively in a planar array and preferably on a common circuit board or part of a cover (not shown). A first strip 128 is disposed to have an upper portion 130 thereof arranged to be contacted by the wiper surfaces 55, 53 of the first contact member 52. Strip 128 has a lower distal portion 132 adapted for connection to a high beam headlamp; and, strip 128 has an intermediate switching portion 134 disposed for being switched by third switching contact 86. A second contact strip 136 is disposed in generally spaced parallel relationship with strip 128 and has an upper portion 137 disposed for being switched by contact member 52 which in association with upper portion 130 of the first strip forms a first switch indicated generally at 138 which is of single pole single throw (SPST) type. Strip 136 has the lower distal end thereof adapted for connection to an on-board source of power as indicated by the B+character in FIGS. 5 through 8 and 12.
A third terminal strip 140 is disposed in spaced parallel relationship with strip 136 and has the upper portion thereof disposed for switching contact with third contact member 86, which in cooperation with strips 136 and 134 comprises a single pole double throw (SPDT) switch indicated generally with reference numeral 141. The lower distal end 142 of strip 140 is adapted for connection to the low beam headlamps.
A fourth terminal strip 144 is disposed in spaced parallel relationship with the distal end 142 of strip 140 and is adapted for connection to the vehicle fog lamps. Strip 144 has the upper end 146 thereof disposed adjacent a fifth terminal strip 148 which in association with fourth contact member 96, comprises a third switch indicated generally at 150 which is of the SPST type. The fifth terminal strip 148 has an upper end portion 152 disposed for being contacted by second contact member 62; and, strip 148 is also disposed adjacent a sixth terminal strip 154 disposed in spaced parallel relationship from the strip 148, with the lower or distal end of strip 154 adapted for connection to a vehicle power supply denoted by reference character B+. The second contact member 62, in association with the strip portion 152 and the upper end 156 of strip 154, functions as a fourth switch of the single pole single throw (SPST) type indicated generally at 158.
Referring to FIG. 12, the relationship of the switch contact members and contact strips described with respect to FIG. 5 is indicated in FIG. 12 wherein the B+power inputs are indicated at the input terminals as connected to strip 136 for the high beam headlamps and contact strip 154 for the fog lamps. The single pole double throw (SPDT) switch 141 is indicated schematically as having side contacts connected respectively to strips 132 for the high beam and 142 for the low beam.
The single pole single throw switch 150 is indicated electrically in series with switch 158 and as having one side thereof connected through strip 144 to the fog lamps with the opposite side connected through the upper portion 152 of strip 148 to one side of switch 158. The opposite side of switch 158 is connected, through strip 154 by movement of second contact 62, to the vehicle power supply. Switch 138 has one side thereof connected through strip 137 to the vehicle power supply; and, the opposite side of switch 138 is connected through contact strip 128 to the high beam lamps by the movement of first contact member 52.
Referring to FIGS. 5 through 10, 12 through 18, the operation of the switch assembly of the present invention will be described wherein the sliding actuator member 34 is moved by a cam 160 rotatable about trunnions 162, 164 which are suitably journalled on the vehicle steering column (not shown); and, the cam is rotated by a block 166 which has attached thereto a stalk lever 168 adapted for user movement thereof to cause rotation of the lever about an axis passing through trunnions 162, 164. Cam 160 is operative to rotate against the outside edge of sliding actuator 34 to effect movement thereof. In the present practice of the invention the cam is profiled to give a sliding stroke to actuator 34 as set forth in Table I below with actuator 34 having a full stroke of about 6.0 millimeters.
TABLE I______________________________________ Percent (%) Stroke ofStalk Lever Rotation Actuator 34______________________________________0° 02° 274° 54.76° 82.2 7.3° 100______________________________________
However, it will be understood that other cam profiles may be employed; and, the amount of stroke of actuator 34 may vary in accordance with the desired sequence of switching. It will also be understood that the configuration and arrangement of the first through sixth terminal strips may be varied to provide a different sequence of switching from that described in FIGS. 9 and 10 within the purview of the invention.
Referring to FIG. 5 and Table I, the sliding actuator 34 is shown in the neutral or at-rest upward position to which it is biased by a suitable spring mechanism (not shown) which may be by any convenient manner well known in the art and which has been omitted from the drawings for simplicity of illustration. The position of the actuator 34 shown in FIG. 5 corresponds to the arrangement of FIG. 13 in which the rotor 84 is latched in its clockwise position by engagement of the end 126 of plunger 118 in detent recess 114. It will be seen from FIGS. 5 and 13 that in the neutral or upward position of actuator 34, the flipper 76 does not engage the cam surface of the rotary switching member 84. It will be understood that the stalk lever 168 is in the 0° lever pull position as defined in the table of Table I.
With the actuator 34 in the upward or neutral position shown in FIG. 5, 9, 10 and 13, the switch 158 is closed and switch 150 is closed by the rotary switching member 84 thereby energizing the fog lamps. The low beam headlamps are energized through switch 141 with switch 138 being open.
Referring to FIGS. 6, 9, 10, 14 and Table I, the user has moved the actuator lever 168 by an amount to cause rotation of 2° about the axis of trunnions 162, 164 and the profile of cam 160 has caused the actuator 34 to move to the position shown in FIGS. 6 and 14, wherein flipper 76 has engaged the side of slot 106 to move partially therealong. The actuator 34 has caused second contact 62 to open switch 158 and has caused first contact 52 to close switch 138. The sequence of events is illustrated with reference to FIG. 9 and Table I wherein at 2° of stalk lever rotation the actuator 34 has moved an amount corresponding to 27% of its full stroke. However, as the actuator passed through approximately 16% of its stroke, switch 158 opened and at approximately 19% of its stroke switch 138 closed to energize the high beam lamps.
Referring to FIGS. 7, 9, 10, 15 and Table I, the stalk lever 168 has been moved by the user to a position corresponding to 4° of rotation whereby the profile of cam 160 has caused actuator 34 to move about 54.7% of its full stroke. In this latter position of the actuator 34, the flipper 76 has engaged the bottom of notch 106 on rotor 84 and has caused the rotor to rotate slightly in a counter-clockwise direction to cause the end 126 of plunger 118 to ramp up the side of recess 114 to the apex 116 of the detent as shown in FIG. 15. In this latter position of the actuator 34, the rotor 84 is at the point of incipient instability; and, switch 141 has closed the connection between contact strips 134 and contact strip 137 and has opened the connection between contact strip 142 and contact strip 137 thereby de-energizing the low beam headlamps. Switch 150 has opened to break a second connection in the circuit for the fog lamps.
Referring to FIGS. 7, 9, 10, 16 and Table I, the stalk lever 168 has been moved by the user an amount of 6° rotation about the trunnions; and, it will be seen from Table I this has caused cam profile 160 to effect movement which corresponds to about 82.2% of the full stroke of actuator 34. As shown in FIG. 16, this results in the flipper 76 engaging the bottom of cam notch 106 and move rotary switching member 84 in a counterclockwise direction to cause the detent apex 116 to move over the center of the end 126 of plunger 118 and ramp down the side of detent 112. With reference to FIGS. 9 and 10 it will be seen that this movement of apex 116 past the end 126 of plunger 118 causes no further switching of the electrical switches 138, 158, 141, 150, but results in latched rotational movement of rotary switching member 84.
Referring to FIGS. 7, 9, 10, 17 and Table I, the stalk lever 168 is shown in the position in which the user has caused full rotation of about 7.3° of stalk lever 168 about the axis of the trunnions. In this position, as shown in FIG. 17, rotary switching member 84 has been moved by flipper 76 engaging the bottom of notch 106 to a position wherein the end 126 of plunger 118 engages the bottom of detent recess 112 and latches the rotor in the fully counterclockwise position.
Referring to FIGS. 7, 9 and 10, rotary switching member 84 is shown with switch 141 having moved to a position causing the contact member 86 to provide connection between B+power strip 136 and strip 134 to provide a dual path or shunt of the power to the strip portion 130 connected to the high beam headlamps. In this position of the rotary switching member 84, switch 150 has opened to provide a second break in the fog lamp circuit. Thus, the high beam headlamps are latched on by rotary switching member 84 being detented by the end 126 of plunger 118.
Referring to FIGS. 8 through 10, the user has released the stalk lever to return the lever to the zero position whereby cam profile 160 has allowed the sliding actuator 34 to return to the neutral position as shown in FIG. 8. In the neutral position of the sliding actuator 34 as shown in FIG. 8, switch 138 is open and switch 158 has re-closed. However, rotary switching member 84 remains in the fully counterclockwise position as shown in FIG. 8, with switch 150 remaining open to prevent switch 158 from energizing the fog lamps; and, switch 141 remains in the position energizing the high beam headlamps. Thus the high beam headlamps are latched on. With reference to FIG. 8 it will be seen that flipper 76 has returned to the neutral position and remains in this position until a subsequent actuation of the lever 168 is effected by the user.
The present invention thus provides a unique, low cost, yet robust and simple to manufacture switching assembly for directly handling headlamp current to provide user control of the low beam and high beam headlamps and fog lamps and includes a flash-to-pass mode of function. The present invention thus permits such a switch to be employed for headlamp and fog lamp control without the necessity of relays.
Upon a subsequent user pull of lever 168, cam profile 160 causes actuator 34 to move downwardly from the position shown in FIG. 8, and flipper 76 engages the side of V-notch 108 causing sufficient movement of actuator 34, according to Table I, to cause rotary switching member 84 to move clockwise and return to the position shown in FIG. 5. Return of the rotor from the FIG. 8 to the FIG. 5 position de-energizes the high beam headlamps and re-energizes the low beam headlamp and fog lamps in reverse sequence.
Although the invention has hereinabove been described with respect to the illustrated embodiments, it will be understood that the invention is capable of modification and variation and is limited only by the following claims. | A switch assembly having a sliding actuator adapted to be moved by a cam on a stalk lever. Initial movement of the actuator from a neutral position by user movement of the lever moves a first contact carried by the actuator to break a connection between a power bus and a fog lamp terminal strip in a planar array of strips. Further movement causes a second contact carried by the actuator to make a connection between another power bus strip and a high beam terminal strip. Continued movement of the sliding actuator causes rotational movement of a bi-stable rotor latched in one of its two bi-stable positions. Movement of the rotor causes a third contact on the rotor to shunt the second contact to make a second connection on another high beam strip and a fourth contact on the rotor breaks a second connection on the strip for the fog lamp electrically in series with the first connection. Subsequent return of the sliding actuator to its beginning or neutral position by user release of the lever does not effect the position of the third and fourth contacts, as the rotor is latched. A subsequent actuation of the stalk lever by the user again moves the sliding actuator to effect movement of the bi-stable member in the opposite direction to disconnect the high beam headlamps and reconnect the low beam and fog lamps, and the bi-stable member is again latched in the position with the low beams headlamps on. | 7 |
TECHNICAL FIELD
[0001] The disclosure relates to a device for protecting a surface from damage caused by wheels or tracks of motor vehicles and a method of manufacturing thereof. More particularly, the device includes a cushion that can be configured to protect a curb from damage.
BACKGROUND OF THE INVENTION
[0002] It is routinely necessary for heavy vehicles such as dozers, excavators, and dump trucks to traverse raised cement edges along roads commonly referred to as curbs. Curbs often crack or crumble due to the load applied to them via the wheels or tracks of the vehicles.
[0003] To protect the curbs, people sometimes cover the curb or fill the transition area between the streets and curb with wood, dirt, or other readily available materials such as tires. In other instances rigid ramps are used to transition between the road surface and the top surface of the curb. Covering the curb and filling in the transition area with available pieces of wood and other random materials yield inconsistent and unreliable results. Often the force from the tires and tracks of the vehicles is transmitted through such protective materials and the curb is nonetheless damaged. It is also common that the protective materials slide away from the curb area as the vehicles traverse the curb, thereby leaving the curb exposed and susceptible to damage.
[0004] Protecting the curb by placing dirt over the curb and in the transition area can be effective. However, using dirt to protect the curb can be overly time-consuming, cumbersome, and messy. Protecting the curb with dirt requires that the operators excavate dirt, place it over the curb area, and remove the dirt after the vehicle has traversed over the curb.
[0005] Ramps have also been used to protect curbs. An exemplary ramp is disclosed in U.S. Pat. No. 5,836,028 (Petersen). The disclosed ramp comprises a rigid construction, which is typical with ramps. Because curb shapes and sizes vary, it is unlikely that any particular rigid ramp can be effectively used to protect different curbs. In addition, since ramps are typically rigid, the forces ramps apply to the road surfaces can be concentrated rather than distributed, thereby causing them to perform poorly. Furthermore, since ramps are designed to support the weight of a heavy vehicle, they are typically very heavy and difficult to transport and manipulate.
[0006] There is a need in the art for a method and device for protecting curbs from damage that is more streamline, efficient, and clean.
SUMMARY OF THE INVENTION
[0007] The disclosure is directed to a device and method for transporting heavy construction equipment over two surfaces separated by an obstacle, such as a curb or a gutter. The device is a cushion that according to some embodiments is constructed of a deformable and resilient material. According to one embodiment, the cushion is positioned at least partially in the transition area between the road surface and the raised curb and over a portion of the upper surface of the curb. The curb cushion protects the curb and also functions as a ramp for facilitating the passing of vehicles over a curb. Given the functionality of the curb cushion it is particularly advantageous for use with heavy vehicles; however, it can be advantageously used with light vehicles such as passenger vehicles and light trucks.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of a curb cushion according to an embodiment of the invention;
[0009] FIG. 2 is a perspective view of a pair of curb cushions of FIG. 1 positioned for use to traverse a first obstacle;
[0010] FIG. 3 is a perspective view of a pair of curb cushions of FIG. 1 positioned for use to traverse a second obstacle;
[0011] FIG. 4 is a side elevation view of the curb cushion of FIG. 1 over a third obstacle;
[0012] FIG. 5 is a side elevation view of the curb cushion of FIG. 4 under a wheeled vehicle;
[0013] FIG. 6 is a side elevation view of the curb cushion of FIG. 4 under a tracked vehicle; and
[0014] FIG. 7 is a side elevation view of a curb cushion of FIG. 1 over a fourth obstacle and under a tracked vehicle.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] The cushion according to the invention is constructed to protect various structures from surface damage while heavy construction vehicles are traveling over them. Referring to FIG. 1 , the cushion is shown as curb cushion 10 that can be used to protect concrete curb and gutter structures located on most streets and parking lots. The curb cushion includes a top 11 , a bottom 13 , a first end portion 15 , and a second end portion 17 . Referring to FIGS. 2 and 3 , the curb cushion 10 of FIG. 1 is shown used with other like curb cushions to protect a first obstacle 12 in FIG. 2 and a second obstacle 14 in FIG. 3 .
[0016] Referring to FIG. 2 , the first obstacle 12 is shown as a set-up type curb 16 that is commonly found along residential streets. The curb includes a lower surface 18 that abuts the road surface (not shown), an upper surface 20 that abuts the lawn or sidewalk 22 , and a transition surface 24 that connects the upper surface 20 and lower surface 18 . Variations of such curb profiles are numerous including, for example, “B 6 ” Style curb (B 612 or B 618 ), “D” Style curbs (D 412 , D 418 , D 612 , D 618 ), or any surmountable curb styles. The word curb used herein is not intended to include or exclude any style of curb. It is used only to refer to the structure typically found adjacent the edges of a road surface. Still referring to FIG. 2 , the curb cushions 10 are shown parallel and spaced apart to align with the wheels or tracks of a vehicle (not shown).
[0017] Referring to FIG. 3 , four curb cushions 10 are used to protect the second obstacle 14 . The curb cushions are position such that they protect the front corner 26 and rear corner 28 of the obstacle 14 . Like in FIG. 2 , the curb cushions 10 are spaced apart and aligned to engage the tires or tracks of a vehicle (not shown). It should be appreciated that the curb cushion 10 may also be used in other applications, such as to provide a ramp and protection over footings and foundations of structures, or a ramp and protection over rigid pipes and sidewalks. The term curb cushion is used instead of simply cushion because protecting curbs is a common application of the cushion according to the present disclosure.
[0018] Referring to FIG. 4 , the curb cushion 10 is shown over a third obstacle 30 . The third obstacle is a curb that includes a lower surface 32 , an upper surface 34 , and a transition surface 36 . The curb shown includes two major stress points 38 and 40 . The major stress points 38 and 40 of the depicted curb are located at an extreme edge of the back of the curb and the extreme edge of the front or face of the curb, respectfully. Due to the particular geometric configuration of the curb, it has a tendency to fail (e.g., chip, crack, and/or crumble) at the major stress points 38 and 40 when heavy vehicles (being wheeled or tracked) travel over the curb.
[0019] Still referring to FIG. 4 , the curb cushion 10 is shown in a static state (i.e., in a normal unloaded state). The first end portion 15 extends over the lower surface 32 of the curb and the second end portion 17 extends over the upper surface of the curb. The first and second end portions 15 and 17 include proximal and distal ends. The distal ends 19 and 21 of the first and second end portions 15 and 17 are coincident with the ends of the curb cushion 10 and the proximal ends of the first and second end portions 15 and 17 are where the first and second end portions 15 and 17 join together in the center of the cushion 10 . According to the depicted embodiment, the major stress points 38 and 40 are covered by the curb cushion 10 . The first end portion 15 covers stress point 40 and the second end portion 17 covers stress point 38 .
[0020] In the depicted embodiment the first end portion 15 extends over the road surface by one or more inches. The bottom surfaces of the first and second end portions 15 and 17 are shown offset by between 4 to 10 inches. The top 11 includes a first ramped surface 23 that slopes up from the distal end of the first end portion 15 and a second ramped surface 25 that slopes up from the distal end of the second end portion 17 . A transition surface 27 connects the ramped surface over the proximal ends of the first and second end portions 15 and 17 . In the depicted embodiment the distance D 1 between the bottom 13 and top 11 in the transition area in its normal state is between 2 to 12 inches. It should be appreciated that in alternative embodiments, many geometric constructions and dimensions are possible. For example, the first end portion 15 may not extend over the road surface and the top 11 could, for example, instead include a single curved profile.
[0021] The curb cushion 10 includes a plurality of cutouts 42 on its underside 13 . The cutouts 42 define a stability core 44 that is positioned between the first end 15 and second end 17 of the curb cushion 10 . The stability core 44 provides structural stability for the vehicle even when the curb cushion 10 is at its most deformed state, thereby keeping the vehicle elevated above the surface of the curb 30 at all times, minimizing any force concentration between the wheels or tracks of the vehicle and the surfaces of the curb 30 . In the depicted embodiment, the curb cutouts 42 are parallel to each other and run across the width of the curb cushion 10 . In addition, in the depicted embodiment the cutouts 42 are angled in a direction away from the bottom surface of the first end portion 15 towards the top 11 and second end portion 17 of the curb cushion 10 . It should be appreciated that many other alternative cutout arrangements are also possible.
[0022] Still referring to FIG. 4 , a relief contour 46 is shown on the underside of the second end of the curb cushion. The relief contour 46 provides a locking feature that keeps the curb cushion 10 in position as the vehicle maneuvers over the curb 30 . In addition, the curb cutouts 42 also lessen weight, enable water to flow under the curb cushion 10 , and serve as handles for easy lifting and manually transporting the curb cushion. The cutouts 42 and relief contour 46 add flexibility to the curb cushion 10 and enable the curb cushion to predictably deform when loaded.
[0023] Referring to FIG. 5 , the curb cushion 10 of FIG. 4 is shown in a dynamic state where a load is applied to the top 11 of the curb cushion 10 via a wheel 50 of a vehicle (not shown). The wheel applies a relatively concentrated force 51 downward into the curb cushion 10 towards the curb 30 . The curb cushion 10 deforms to fit the surface profile of the curb 30 and transmits the force 51 from the wheel 50 more evenly along the surface 36 of the curb 30 as shown by arrows 53 . By distributing the force 51 across the surface of the curb 30 more evenly, the curb is less likely to be damaged by the wheel 50 of the vehicle. In addition to preventing failure of the curb 30 , the curb cushion 10 acts as a ramp to facilitate the passing of the vehicle over the curb 30 .
[0024] Referring to FIG. 6 , the curb cushion of FIG. 4 is shown in a dynamic state where a load is applied to the top of the curb cushion 10 via the track 60 of a tracked vehicle such as a dozer (not shown). In the depicted embodiment the downward force 61 applied from the track 60 is distributed across the top surface 11 of the curb cushion. The curb cushion deforms to the space between the track and the curb 30 and distributes the force 61 of the track 60 across the surface profile of the curb 30 shown by arrows 63 . If the curb cushion 10 was not positioned between the track 60 and the curb 30 , the track would apply a concentrated force at localized areas of the surface of the curb 30 , which would likely lead to failure of the curb surfaces 32 , 34 , 36 . Like in FIG. 5 , the curb cushion 10 redistributes and evens out the force applied from the vehicle onto the curb 30 to help prevent curb 30 from failure.
[0025] Referring to FIG. 7 , the curb cushion 10 of FIG. 1 is shown over a curb 70 that has a different surface profile as compared to curb 30 . However, like curb 30 curb 70 includes major stress points 71 and 72 that are defined as locations on the curb that are most susceptible to failing. The curb cushion 10 extends over the major stress points 71 and 72 . The curb cushion 10 protects the curb by deforming and redistributing the force across the surface of the curb 70 . The cutouts 42 and relief contour 46 are constructed to enable the curb cushion to predictably deform and be adaptable for use on a wide range of different curb profiles. The cutouts 42 and relief contour 46 also help keep the curb cushion 10 relatively stationary when the vehicle moves across the top 11 of the curb cushion 10 , as the curb cushion tends to deform when engaged by the track 60 or wheel 50 rather than slide away as would a more rigid object. It should be appreciated that though four cutouts 42 and one relief contour 46 are shown, an alternative embodiment of the curb cushion 10 may include any suitable number of cutouts 42 are relief contours 46 .
[0026] Referring back to FIG. 4 , the depicted embodiment is sized to work well with most curb structures which are between 16 to 32 inches in width C. To work with most curb and gutter structures the overall length L 2 of the curb cushion 10 is preferably between 36 to 48 inches long and most preferably 40 inches long. The width W is preferably between 12 to 24 inches wide and most preferably 18 inches wide (see FIG. 3 ). The height H is between 8 to 12 inches and most preferably 10 inches high. It should be appreciated that the curb cushion can be manufactured in other geometric orientations and sizes as appropriate for its intended application(s).
[0027] In the depicted embodiment the curb cushion 10 is molded out of a flexible material such as dense urethane foam, dense rubber product, or a combination of both. In alternative embodiments the curb cushion 10 can be constructed of other deformable materials or from a combination of materials, some being more deformable than others. For example, in an alternative embodiment the top 11 of the curb cushion 10 could be constructed of a harder plastic material that is adhered to the body portion of the curb cushion to protect the top 11 against abrasion. Preferably, the curb cushion is constructed such that it is heavy enough to maintain position over the curb and gutter, yet light enough to be easily transported by an individual. The preferred design weight is 25 to 50 pounds per cushion.
[0028] The above specification, examples, and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. | The cushion according to one embodiment is a deformable resilient apparatus with a surface for allowing various vehicles to transverse from a first surface to a second surface that are separated by an obstacle without damaging the obstacle. The cushion deforms to fit the space between the vehicle and the obstacle, thereby preventing concentration of stress on the obstacle. The cushion is constructed such that it does not slide out of place when engaged by tracks or wheels of a vehicle. The cushion is constructed to deform and distribute the force applied by the vehicle onto the object more uniformly. | 4 |
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